2015 Electric System Reliability Performance Report

Transcription

1 2015 Electric System Reliability Performance Report February 25 th, 2016 Prepared by System Planning & Protection Distribution and Engineering Services Division SNOHOMISH COUNTY PUBLIC UTILITY DISTRICT NO. 1 Everett, Washington

2 Executive Summary This report describes the Snohomish County PUD s (District) electric system reliability performance from January 1, 2015, through December 31, During 2009, the District modified reporting practices for weather events that were not classified as a major storm. In 2013, the District modified the way in which the major storm and major event categories are applied to outages. Now all outages that occur outside of a major event are tracked in the District s Outage Report System (ORS). Outages that occur during major events are not recorded in ORS. These changes were made to increase consistency in data-gathering, analysis, and comparison, and as a viable alternative to the major event day method described in IEEE Guideline 1366 Guide for Electric Power Distribution Reliability Indices. An event is only to be considered a major event when it is declared so by the Incident Commander. District customers lost power for an average of 81.0 minutes (SAIDI) in 2015 during routine operation. This is lower than the five-year average of 86.6 minutes. The District guideline for the maximum amount of time that customers lose electric service on average over a one-year period is 80 minutes. The 2015 average of 81.0 minutes exceeds the guideline limit. Appendix C provides additional data on historical performance. District customers lost power an average of 0.85 times (SAIFI) in 2015 during routine operation. This is lower than the five-year average of 0.90 interruptions. The District guideline for the average number of power outages to each customer is less than one per year, so the average for 2015 meets District guidelines for reliable service. The average length of time required to restore power after an outage was 95.0 minutes (CAIDI) in 2015 during routine operation. This is lower than the five-year average of 96.8 minutes, but both exceed the District guideline limit of power restoration in less than 80 minutes on average. There were 3 declared major event in Outage information for these major events were not recorded. Section 3 of this report details the data described here. ii 2015 Electric System Reliability Report

3 Table of Contents Executive Summary iii 1 Background Introduction Statistical indicators used Outage Data Collection Record-keeping Record-keeping during major events Record-keeping and OMS System Reliability Statistics Data for Historical Perspective Major Events Effect of Major Events on the District Major Events The Transmission System Introduction Outages The Distribution System Introduction System Performance Outage Causes Explanation of Equipment Failure Category The Cause of Outages on the Twenty Circuits with the Greatest Number of Outages Tree-Related Outages Underground Cable-Related Outages Distribution Automation Electric System Reliability Report iii

4 Table of Figures Figure 3-1 SAIDI Figure 3-2 Non-Storm System Reliability Indices Figure Distribution Outages by Cause (% of total number of outages) Figure 6-2 Five-Year Average Distribution Outages by Cause Figure Distribution Outages by Cause (% of total customer minutes) Figure 6-4 Five-Year Average Distribution Outages by Cause Figure 6-5 Equipment Failures Figure 6-6 Equipment Failures Five-Year Average ( ) Figure 6-7 Cause of Outages on the Twenty Circuits with the greatest number of distribution outages Figure 6-8 SAIDI by Outage Cause for the Twenty Circuits with the greatest number of distribution outages Figure 6-9 Tree-related outage count over the past five years Figure 6-10 Tree-related SAIDI over the past five years Figure 6-11 Tree-related CAIDI over the past five years Figure 6-12 Underground primary and secondary cable failure outages iv 2015 Electric System Reliability Report

5 List of Tables Table 3-1 General Descriptive Data... 9 Table 3-2 Outage Data for Table 3-3 Five-Year Average Annual Outage Data for the Period Table 3-4 SAIDI Table 3-5 Non-Storm System Reliability Indices Table Sustained Transmission Outages Table 6-1 The Twenty Circuits that had the greatest number of distribution outages in Table Tree-Related Outages Table 6-3 Distribution Automation Circuits Table 6-4 DA Study area reliability indices versus District s entire system Electric System Reliability Report v

6 1 Background 1.1 Introduction Understanding the causes of outages and developing methods or programs to reduce their rate of occurrence are two of the most important goals in the operation of any electric utility. This report identifies the causes of the outages in 2015 and their impacts on system reliability. The District receives power from the Bonneville Power Administration at three delivery points, the Murray, SnoKing, and Snohomish substations. Transmission lines from those substations deliver power at 115,000 Volts to 88 (including Jackson hydro) distribution substations and switching stations in the District s service area. A typical distribution substation has four 12,500 Volt circuits and serves an average of 4,000 customers. Long circuits characterize the eastern and northern areas of the county, with high tree exposure through rural areas. These circuits experience relatively more outages. The urban and suburban areas in Everett and the south county area typically have shorter circuits and fewer outages. 1.2 Statistical indicators used The District measures electric system reliability using three indicators defined by the Institute of Electrical and Electronics Engineers (IEEE). The definitions come from the current revision of IEEE Standard IEEE Guide for Electric Power Distribution Reliability Indices. The standard defines these indices as sustained interruption indices, meaning a loss of service to one or more customers for more than five minutes. The District has always used one minute to define a sustained outage, rather than five minutes. The District General Planning Guidelines for Electric Facilities include limits for each index to evaluate the electric system for reliable performance. SAIDI (System Average Interruption Duration Index) This index measures the total duration of interruption for the average customer during a predefined period of time. It is commonly measured in customer minutes or customer hours of interruption. Mathematically, this is calculated using the following equation: SAIDI = Customer Interruption Durations Total number of Customers Served SAIDI can be calculated for any defined set of customers, such as all customers served from a specific circuit, all customers served from a specific substation, or for all District customers Electric System Reliability Report

7 CAIDI (Customer Average Interruption Duration Index) This index represents the average time required to restore service to customers after an interruption. Mathematically, this is calculated using the following equation: CAIDI = Customer Interruption Durations Total number of Customers Interrupted CAIDI can also be calculated for any defined set of customers. SAIFI (System Average Interruption Frequency Index) This index indicates how often the average customer experiences a sustained interruption over a predefined period of time. Mathematically, this is calculated using the following equation: SAIFI = Total number of Customers Interrupted Total number of Customers Served Similar to SAIDI and CAIDI, SAIFI can be calculated for any defined set of customers Electric System Reliability Report 7

8 2 Outage Data Collection 2.1 Record-keeping The District uses a computerized record-keeping system called ORS to record information on outages occurring during routine operations. The ORS data is limited to information on outages that did not occur during a major event. As mentioned in the Executive Summary, changes to the recording practices for weather events were made during the second quarter of 2009 and changes to outage categories were made in In past years, the recording and entry of outage information into ORS was suspended during storms and unusual weather events. The District has made a decision to change this practice and to record outage information for storms and/or weather events as long as they are not major events. Since 2009, outages that occur during unusual weather events are included in ORS and reported as normal outage information. The purpose of this change is to be more consistent in outage information recording. 2.2 Record-keeping during major events Events are designated as major events by the Incident Commander. A general guideline for declaring a major event is that at least 10% of the District s customers are affected and restoration times are expected to exceed 24 hours. This prevents transmission or substation outage events which are restored relatively quickly from being classified as major events. The District will continue to estimate the outage statistics for major events using Supervisory Control and Data Acquisition (SCADA) - recorded substation circuit breaker operation information until a more robust outage management system is fully implemented. These estimates do not account for any switching performed to restore electric service, nor do they account for system problems that do not result in a circuit breaker operation. 2.3 Record-keeping and OMS Starting in 2016, the District will implement an Outage Management System (OMS) to track customer outages and abnormal system conditions. With this system, manual entry of outage records will no longer be required as computerized records of switching operations will generate a report of customer outage minutes. The effect of implementing this new system will most likely be that SAIDI and SAIFI will increase, as all customer outages will be accounted for automatically Electric System Reliability Report

9 3 System Reliability Statistics 3.1 Data for 2015 The tables below show the statistical data for outages in 2015, as well as average data for the five previous years. Refer to Section 1 for definitions of the terms SAIDI, CAIDI, and SAIFI. The 2015 non-major event total system SAIDI and SAIFI values were lower than the five-year averages. There were three declared major events in Table 3-1 General Descriptive Data Year 2015 System Customers 359,854 Area Served 2,200 square miles Table 3-2 Outage Data for 2015 (Sustained Outage > 1 Minute) SAIDI CAIDI SAIFI Customers Affected Distribution: ,048 Transmission: ,109 Overall: ,157 Declared Major Events 1, ,321 Total 1, , Electric System Reliability Report 9

10 Table 3-3 Five-Year Average Annual Outage Data for the Period (Sustained Outage > 1 Minute) SAIDI CAIDI SAIFI Customers Affected Distribution: ,235 Transmission: ,674 Overall: ,909 Declared Major Event ,712 Total , Electric System Reliability Report

11 3.2 Historical Perspective Table 3-4 and Figure 3-1 show the outage data in terms of the average number of minutes each customer lost power per year (SAIDI) for the past twenty-five years. Figure 3-1 uses the right axis to display the major event SAIDI values. The left axis displays the routine operation SAIDI values. Note that problems on the distribution system contribute more to SAIDI than do problems on the transmission system. The 1993 SAIDI value includes the Inaugural Day storm. Table 3-4 SAIDI Year Distribution Transmission Overall Weather Major Event Event Not Available Not Available Not Available Not Available Not Available Not Available Not Available Not Available Not Tracked 34.2 Separately Not Tracked 0.0 Separately Not Tracked 44.2 Separately Not Tracked 0.0 Separately Not Tracked Separately Not Tracked Separately 1, Electric System Reliability Report 11

12 Figure 3-1 SAIDI Non storm and weather event (Customer minutes) Distribution Transmission Declared Major Event Declared Major Events (Customer minutes) Electric System Reliability Report

13 Table 3-5 Non-Storm System Reliability Indices Year SAIDI CAIDI SAIFI Electric System Reliability Report 13

14 Figure 3-2 Non-Storm System Reliability Indices SAIDI & CAIDI (Customer Minutes) SAIDI CAIDI SAIDI/CAIDI Goal SAIFI SAIFI Goal SAIFI 4 Major Events 4.1 Effect of Major Events on the District The Assistant General Manager of the Distribution and Engineering Services Division (the Incident Commander) is responsible for declaring a major event. In past years, major events have been declared when the following criteria are met: normal operations of the District are impacted; the service restoration time typically lasts longer then twenty-four hours; thousands of customers are impacted; and all available personnel pertinent to a major event are utilized. When thousands of customers have been out of power and more outages have occurred than could be immediately handled, District Staff has curtailed normal record-keeping efforts in order to concentrate on restoration of service. For that reason, the statistical information provided by ORS does not include major event outage data. Instead, this section comprises major event statistics estimated using data gathered from SCADA records. The definition of a major event has been revised to include the additional criterion that at least ten percent of the customers served by the District are out of service. The District will make the decision whether or not to record outage information during a declared major event on a case-by-case basis Electric System Reliability Report

15 Major Events There were three major event declared in Early in the day on Sunday, January 18 th high winds caused breakers to open at Murphy s Corner, Picnic Point, Park Ridge, Hilton Lake, Five Corners, South Camano and Brier. At one point there were 19 breakers locked open. When limited crews were available to respond, a major event was declared, with three tree crews and four line crews brought in. By Monday afternoon most customers were back in service. The storm was declared over at 6 P.M. on Monday, January 19 th. During the course of the storm, 27 breakers opened, (some multiple times) at 21 substations. A total of 36,500 customers experienced a sustained outage. Warm temperatures, extremely dry conditions, and high winds mixed together to create a storm that caused massive wide-spread damage to the county early in the day on Saturday, August 29 th, with five major transmission lines and 17 substations offline. By the time the storm was declared at 2 P.M., approximately 150 breakers had opened. By the end of the day, a total of 180 breakers had opened, some more than once. To help with restoration, 14 contract line and 16 tree crews were brought in. At the time, this storm caused more damage to the District s system than any event to date. However, all repairs were complete within five days, and the storm was declared over on September 3 rd. In total, 311,525 customers experienced a sustained outage. On Tuesday, November 17 th, high winds caused more than 50 breakers opened in a half hour span, and a major event was declared. During the storm, 142 breakers at 60 substations locked open. The District brought in 39 contract crews to help with restoration. In total, 205,573 customers experienced a sustained outage. Table Declared Major Events Date Peak Wind Speed Customers Affected Transmission Customers Affected Distribution Total Customers Affected SAIDI 1/18/ ,500 36, /28/ , , , /17/ , , , Note: The calculation for the number of customers affected by a sustained outage multiplies each circuit breaker operation by the number of customers fed by each breaker. One customer counts several times if the associated circuit breaker operates several times Electric System Reliability Report 15

16 5 The Transmission System 5.1 Introduction For consideration as a transmission outage, an outage must involve the operation of a 55 kv or 115 kv protective device, such as a circuit switcher or power circuit breaker. Transmission system outages usually have an impact on a significant number of customers. 5.2 Outages Of 42 transmission system operations in 2015, the District experienced twelve non-storm sustained transmission or substation outages and nine momentary (less than one minute duration) outage events, resulting in a total of 6,093,396 customer outage minutes. An additional seventeen sustained outages and four momentary outages occurred during storms. These outages were not included in the reliability statistics for the year. Table 5.1 provides summary information for each transmission or substation operation during Table Sustained Transmission Outages Outage Number Date Line or Device Cause 1 1/18/2015 Halls Lake Ballinger 115 kv line Unknown (Storm) 2 3/16/2015 BPA Snohomish BPA Murray 115 kv line Inadvertent contact 3 4/15/2015 Halls Lake-Paine Field 115 kv line Inadvertent contact 4 4/23/2015 BPA Snohomish-BPA Murray 115 kv line Tree 5 5/11/2015 Beverly Park - Paine Field 115 kv line Unknown 6 5/23/2015 BPA Snohomish - Jackson South Loop 115 kv line Unknown 7 6/8/2015 Delta-Stimson (D-SC) 115 kv line Tree 8 6/25/2015 Paine Field Bank 2 Worker error 9 7/23/2015 Glenwood substation Vandalism 10 8/5/2015 Mukilteo substation Equipment failure 11 8/10/2015 BPA Snohomish - Jackson North Loop 115 kv Line Unknown 12 8/15/2015 BPA Murray-Stimson Crossing 115 kv line Lightning 13 8/29/2015 Halls Lake-Five Corners 115 kv line Downed line (Storm) Electric System Reliability Report

17 Outage Number Date Line or Device Cause 14 8/29/2015 BPA SnoKing Halls Lake #1 115 kv line Tree (Storm) 15 8/29/2015 BPA SnoKing Halls Lake #2 115 kv line Unknown (Storm) 16 8/29/2015 BPA Snohomish - BPA Murray 115 kv line Unknown (Storm) 17 8/29/2015 East Arlington-Stimson Crossing 115 kv Line Unknown (Storm) 18 8/29/2015 Delta-Stimson (D-SC) 115 kv line Unknown (Storm) 19 9/2/2015 East Arlington kv Bank 3 Unknown 20 9/4/2015 East Arlington kv Bank 3 Unknown 21 9/4/2015 Stimson Crossing Camano Island 115 kv line Unknown 22 9/6/2015 East Arlington kv Bank 3 Unknown 23 10/8/2015 Delta Stimson Crossing (D-M) 115 kv line Unknown 24 10/10/2015 BPA SnoKing Beverly Park 115 kv line Equipment failure 25 10/15/2015 Lake Goodwin PCB Unknown 26 10/28/2015 North Marysville substation Arcing 12 kv switch 27 10/30/2015 Lake Goodwin PCB Tree 28 11/17/2015 BPA SnoKing Brightwater 115 kv line Unknown (Storm) 29 11/17/2015 BPA Snohomish - Scott 115 kv line Downed line (Storm) 30 11/17/2015 Halls Lake-Five Corners 115 kv Line Downed line (Storm) 31 11/17/2015 Halls Lake-Paine Field 115 kv Line Tree (Storm) 32 11/17/2015 Beverly Park-Paine Field 115 kv line Unknown (Storm) 33 11/17/2015 BPA Snohomish-Boeing 115 kv line Unknown (Storm) 34 11/17/2015 BPA Snohomish BPA Murray 115 kv line Unknown (Storm) 2015 Electric System Reliability Report 17

18 Outage Number Date Line or Device Cause 35 11/17/2015 Delta-Stimson Crossing (D-SC) 115 kv line Tree (Storm) 36 11/17/2015 BPA Murray-Stimson Crossing 115 kv line Unknown (Storm) 37 11/17/2015 East Arlington-Stimson Crossing 115 kv line Unknown (Storm) 38 11/17/2015 BPA Snohomish - Delta 115 kv line Unknown (Storm) 39 11/17/2015 BPA SnoKing - Beverly Park 115 kv line Tree (Storm) 40 11/18/2015 Beverly Park-Paine Field 115 kv line Unknown (Storm) 41 11/19/2015 Beverly Park-Paine Field 115 kv line Unknown (Storm) 42 12/12/2015 BPA SnoKing Halls Lake #2 115 kv line Tree Transmission outages contributed 16.9 minutes to the yearly non-storm SAIDI, 37% higher than the previous five years average Transmission SAIDI of 12.3 minutes. Following is additional information pertaining to each outage listed in Table Halls Lake Ballinger 115 kv line. This line tripped during a wind storm and reclosed successfully, causing a momentary interruption to customers served by Ballinger, Richmond Park, and Westgate substations. The cause of the fault was not identified. 2. BPA Snohomish BPA Murray 115 kv line. This line tripped due to a contractor s equipment inadvertently contacting the line during work on a cell tower adjacent to the line, then reclosed successfully. This caused a momentary interruption to customers served by Granite Falls, Hartford, East Marysville, Frontier, Lake Stevens, and Bunk Foss substations. 3. Halls Lake Paine Field 115 kv line. This line tripped when a telephone wire hit by a truck made contact with the line, then reclosed successfully. This caused a momentary interruption to customers served by Gibson, Lake Serene, Meadowdale, and Keeler s Corner substations. 4. BPA Snohomish BPA Murray 115 kv line. This line tripped due to a tree in the line between BPA Murray substation and Granite Falls substation. The automatic sectionalizing scheme at East Marysville operated to sectionalize the line and limit the interruption at East Marysville, Frontier, Lake Stevens, and Bunk Foss to a momentary. Customers served by Granite Falls and Hartford substations experienced sustained outages due to this operation. 5. Beverly Park Paine Field 115 kv line. The line tripped and reclosed successfully, causing a momentary interruption to customers served by Casino, Picnic Point, Harbour Pointe, and Mukilteo substations. Cause of the fault was not investigated Electric System Reliability Report

19 6. BPA Snohomish Jackson South Loop 115 kv line. The line tripped and reclosed successfully, causing a momentary interruption to customers served by Snohomish, West Monroe, Woods Creek, Sultan, Wallace River, and Gold Bar substations. Cause of the fault was not investigated. 7. Delta Stimson Crossing (D-SC) 115 kv line. The line tripped due to a fallen limb caused by tree trimming and did not reclose due to incorrect relay programming in the lead station s relay. This caused a sustained outage to customers served by Quil-Ceda and Village substations. Tulalip substation was offloaded at the time, and so was unaffected by this operation. 8. Paine Field Bank 2. The transformer lockout relay operated due to worker error during construction to replace the station 115 kv differential relay scheme. This caused a sustained outage of three minutes to all customers served by this transformer. 9. Glenwood substation. The station was taken off-line due to unsafe conditions created when vandals removed the station transformer ground connection. All customers served by this transformer experienced a sustained outage while switching was performed to pick up the load. 10. Mukilteo substation. The station was taken off-line due to a dead station battery caused by a failed battery charger. All customers served by this transformer experienced a sustained outage while switching was performed to pick up the load. 11. BPA Snohomish Jackson North Loop 115 kv line. The line tripped and reclosed successfully, causing a momentary interruption to customers served by Three Lakes and Lake Chaplain substations. Cause of the fault was not investigated. 12. BPA Murray Stimson Crossing 115 kv line. The line tripped out when lightning damaged an insulator, causing sustained outages to customers served by Edgecomb and Smokey Point substations. 13. Halls Lake Five Corners 115 kv line. The line tripped and locked out during the windstorm due to multiple spans of wire down between the Edmonds tap and Maplewood substation. The autosectionalizing scheme at Lynnwood substation operated to limit the interruption to Lynnwood to momentary. Customers served by Maplewood and Perrinville substations experienced a sustained outage. 14. BPA SnoKing Halls Lake #1 115 kv line. The line tripped and locked out during the windstorm due to a tree in the line. Because the Thrashers Corner auto-sectionalizing scheme was disabled at the time, it did not operate, so customers served by both Thrashers Corner and Brier substations experienced a sustained outage. 15. BPA SnoKing Halls Lake #2 115 kv line. The line tripped and successfully reclosed twice during the windstorm. Cause of the trip was not investigated. The Mountlake Terrace autosectionalizing scheme operated as designed both times. Customers served by both Mountlake Terrace and Canyon Park substations experienced momentary outages. 16. BPA Snohomish BPA Murray 115 kv line. This line tripped multiple times during the windstorm. Causes of the trips were not recorded. The automatic sectionalizing scheme at East Marysville operated correctly when called upon, but all customers served by Granite Falls, Hartford, East Marysville, Frontier, Lake Stevens, and Bunk Foss experienced several lengthy sustained outages due to these operations Electric System Reliability Report 19

20 17. East Arlington Stimson Crossing 115 kv line. This line tripped out multiple times during the windstorm, causing sustained outages to customers served by Portage and Lake Goodwin substations. 18. Delta Stimson Crossing (D-SC) 115 kv line. The line was being fed radially due to relay upgrade work in progress at Delta substation when it tripped during the windstorm. This terminal did not reclose due to the system configuration (this terminal closes only on a hot line). This caused a sustained outage to customers served by Village, Quil-Ceda, and Tulalip substations. Cause of the fault was not recorded. 19. East Arlington kv Bank 3. This bank tripped out with targets on all three phases. Later investigation determined that the most likely cause is a failing phase of the 55 kv grounding transformer. This outage caused a sustained outage to customers fed from Oso substation. 20. East Arlington kv Bank 3. This bank tripped out with targets on all three phases. Later investigation determined that the most likely cause is a failing phase of the 55 kv grounding transformer. This outage caused a sustained outage to customers fed from Oso substation. 21. Stimson Crossing Camano Island 115 kv line. The line tripped and reclosed successfully, causing a momentary outage to customers served by North Stanwood, Camano, Sunset, and South Camano substations. Cause of the trip was not investigated. 22. East Arlington Bank kv Bank 3. This bank tripped out with targets on all three phases. Later investigation determined that the most likely cause is a failing phase of the 55 kv grounding transformer. This outage caused a sustained outage to customers fed from Oso substation. 23. Delta Stimson Crossing (D-M) 115 kv line. The line tripped and reclosed successfully, causing a momentary outage to customers served by North Marysville, Kellogg Marsh, and Central Marysville substations. Cause of the trip was not investigated. 24. BPA SnoKing Beverly Park 115 kv line. The line tripped due to failed insulators at NC 0/8. The auto-sectionalizing scheme at Mariner operated correctly, limiting the interruption to customers served by Mariner and Silver Lake substations to a momentary outage. Customers served by Polaris and Martha Lake experienced a sustained outage. 25. Lake Goodwin PCB The line tripped and reclosed successfully. No customers were affected by this operation. Cause of the trip is as yet unknown. 26. North Marysville substation was taken offline due to arcing on the 12 kv bank main disconnect switch. Customers served by the substation experienced a sustained outage while switching was performed to restore service. 27. Lake Goodwin PCB tripped to lockout due to a tree in the line. The outage also involved Lake Goodwin circuit , which is underbuilt on the 115 kv structures. No customers were affected by the operation of the 115 kv breaker. 28. BPA SnoKing Brightwater 115 kv line. The line tripped during the windstorm and the BPA SnoKing terminal reclosed successfully while the Brightwater terminal relayed to lockout. This caused a momentary outage to customers served by Park Ridge substation. 29. BPA Snohomish Scott 115 kv line. During the windstorm, this line tripped and reclosed successfully three times, with the auto-sectionalizing scheme at Fifty-Second Street operating as designed each time. On the fourth trip, the BPA Snohomish terminal relayed to lockout due to conductor down between BPA Snohomish and Pinehurst substation. Outages in each case were Electric System Reliability Report

21 limited to momentary interruptions to customers served by Waterfront and Fifty-Second street substations, while customers served by Pinehurst also experienced a sustained outage following the fourth line trip. 30. Halls Lake Five Corners 115 kv line. During the windstorm, the line tripped to lockout due to downed conductor between Perrinville and Lynnwood substations. The auto-sectionalizing scheme at Lynnwood operated to limit the interruption to customers served by this substation to a momentary outage, while customers served by Perrinville, Maplewood, and Five Corners substations experienced a sustained outage. 31. Halls Lake Paine Field 115 kv line. During the windstorm, this line tripped due a tree in the line just outside Lake Serene substation. The auto-sectionalizing scheme at Lake Serene operated to sectionalize the line, which limited the interruption to customers served by Meadowdale, Keeler s Corner and Lynnwood substations (which had earlier automatically transferred to this line following a fault on its normal source) to a momentary outage, while customers served by Gibson and Lake Serene experienced a sustained outage. The Lake Serene auto-sectionalizing scheme operated incorrectly during this event, resulting in a sustained outage rather than a momentary outage to customers served by the station. The error has since been identified and corrected. 32. Beverly Park Paine Field 115 kv line. During the windstorm, this line tripped for a fault between Harbour Pointe and Picnic Point. The Beverly Park terminal reclosed after the autosectionalizing scheme at Picnic Point had operated to sectionalize the line, which limited interruptions to customers served by Casino and Picnic Point substations to momentary outages. However, customers served by Harbour Pointe and Mukilteo substations experienced sustained outages due to this fault even though the faulted section was between Harbour Pointe and Picnic Point because each time the auto-sectionalizing scheme had reset before the fault re-initiated. Cause of the trip was not recorded. 33. BPA Snohomish Boeing 115 kv line. During the windstorm, this line tripped to lockout and was out for an extended period. Because no customers are directly served by this line, no customer outages resulted from this operation. Cause of the trip was not recorded. 34. BPA Snohomish BPA Murray 115 kv line. During the windstorm, the line tripped twice, with the East Marysville auto-sectionalizing scheme operating correctly in both instances. The first operation was a temporary fault, causing a momentary interruption to customers served by Granite Falls, Hartford, East Marysville, Frontier, Lake Stevens, and Bunk Foss substations. The second operation was due to a tree in the line between BPA Murray and Granite Falls substations, which resulted in momentary interruptions to customers served by East Marysville, Frontier, Lake Stevens, and Bunk Foss and sustained outages to customers served by Granite Falls and Hartford substations. Cause of the trip was not recorded. 35. Delta Stimson Crossing 115 kv line. The line tripped to lockout during the windstorm due to a tree in the line. This resulted in sustained outages to customers served by Tulalip, Village, and Quil-Ceda substations. 36. BPA Murray-Stimson Crossing 115 kv line. During the windstorm, the line tripped and reclosed successfully, resulting in momentary interruptions to customers served by Smokey Point and Edgecomb substations. Cause of the trip was not recorded Electric System Reliability Report 21

22 37. East Arlington Stimson Crossing 115 kv line. During the windstorm, the line tripped twice, reclosing successfully the first time. During the second trip, both terminals relayed to lockout, resulting in sustained outages to customers served by Lake Goodwin and Portage substations. Cause of the trip was not recorded. 38. BPA Snohomish Delta 115 kv line. During the windstorm, this line relayed and reclosed successfully. The auto-sectionalizing scheme at Fobes did not operate because the station was offline. Customers served by Tenth Street substation experienced a momentary outage due to this operation. Cause of the trip was not recorded. 39. BPA SnoKing Beverly Park 115 kv line. During the windstorm, the line relayed out due to a tree in the line between Beverly Park and the Silver Lake tap. The BPA SnoKing terminal reclosed successfully and the Beverly Park terminal locked out following operation of the autosectionalizing scheme at Mariner. This operation resulted in momentary outages to customers served by Mariner, Martha Lake, and Polaris substations and sustained outages to customers served by Silver Lake substation. 40. Beverly Park Paine Field 115 kv line. The line tripped while switching was in progress to restore the line to normal following repairs to the section between Harbour Pointe and Picnic Point. Customers served by Mukilteo, Harbour Pointe, and Picnic Point experienced another sustained outage of several minutes due to this operation. 41. Beverly Park Paine Field 115 kv line. The line tripped while switching was in progress to restore the line to normal following repairs to the section between Harbour Pointe and Picnic Point. Customers served by Mukilteo, Harbour Pointe, and Picnic Point experienced another sustained outage of several minutes due to this operation. 42. BPA SnoKing Halls Lake #2 115 kv line. The line tripped due to a tree in the at SK-HL#2 7/8, and the auto-sectionalizing scheme at Mountlake Terrace substation operated to sectionalize the line. The BPA terminal relayed to lockout, but Halls Lake reclosed successfully, restoring service to customers served by Mountlake Terrace substation after a momentary interruption. Customers served by Canyon Park and Fitzgerald substations experienced a sustained outage due to this operation Electric System Reliability Report

23 6 The Distribution System 6.1 Introduction This section describes the outages on the District kv distribution system. These outages are more frequent and involve fewer customers per event than most transmission system outages. The ORS Outage Cause Codes were modified in 1993 to provide improved differentiation of tree-related outages, which allows the District to better focus its tree trimming efforts. A tree, any part of which is located within twelve feet of a distribution line, causes a preventable tree-related outage. A tree causes a non-preventable tree-related outage when its trunk or branches are located more than twelve feet from a distribution line. Beginning in 1996, the District began an effort to improve tree-related outage records. Thus, it is possible to make year-to-year comparisons between like types of tree-related outages since 1997, as well as total tree-related outage comparisons from year to year. The ORS Outage Cause Codes were also modified in 1993 to distinguish between fatigued fuses and failed fuses. A fatigued fuse refers to a fuse that opens at a lower current level than designed because previous through-fault currents or excessive load have altered its characteristic time-current response. A fatigued fuse is more likely to occur on feeders where fuse saving or instantaneous overcurrent protection is applied, and may involve significant numbers of customers. A fuse-saving protection scheme is designed to allow the circuit breaker to momentarily (for five or ten seconds) open for faults on the load side of the line fuses. This instantaneous, or non-time-delayed, operation of the breaker is completed before the fuse opens, and results in a momentary interruption of service to all customers served from the circuit. If the fault were temporary, such as a tree branch falling through a line, the breaker would successfully reclose, restoring service to the entire circuit, with the fuse remaining intact. This practice can reduce the number of sustained interruptions to customers and the resulting District field labor expense, but all customers on the circuit experience a momentary outage and the fault current can damage the fuse. This can create a weak link, which can open unpredictably under load at some future time. A failed fuse refers to a mechanical failure such as a broken fuse link. Fatigued fuses have their own category in ORS, but failed fuses are included in the larger category of equipment failure. The distinction between fatigued and failed fuses was made to identify areas experiencing a high number of fatigued-fuse outages, and to guide District outage-reduction efforts in these areas Electric System Reliability Report 23

24 6.2 System Performance Outage Causes Figures 6-1 and 6-2 compare 2015 distribution outages to five-year average outages by cause. The electric system experienced 1,152 distribution outages in 2015 during routine operation, compared to the five-year average of 1,469 outages. The percentages shown in Figures 6-1 and 6-2 are percentages of these total numbers of outages. Figure Distribution Outages by Cause (% of total number of outages) Trees or limbs, man-caused 0% Prearranged / planned 0% Other utility 0% Other 1% Operating error 0% Motor vehicle 5% Lightning 2% Fatigued fuse 7% Trees or limbs, non-preventable 21% Trees or limbs, preventable 8% Equipment failure 18% Unknown 12% Bird or animal 25% Underground dig-in 1% Electric System Reliability Report

25 Figure 6-2 Five-Year Average Distribution Outages by Cause (% of total number of outages, ) Unknown 8% Trees or limbs, preventable 7% Underground dig-in 1% Trees or limbs, man-caused 1% Trees or limbs, non-preventable 27% Bird or animal 17% Other 2% Equipment failure 21% Motor vehicle 4% Lightning 3% Fatigued fuse 12% 2015 Electric System Reliability Report 25

26 Figures 6-3 and 6-4 compare 2015 to five-year average distribution outages by customer outage minutes. District customers lost power for a combined total of 23,065,639 minutes in 2015 due to distribution outages, compared to the five-year average of 24,945,708 minutes. The percentages shown in Figures 6-3 and 6-4 are percentages of these total number of outage minutes. Both the number of outages and the customer minutes of outage are important parameters for planning effective outage-reduction measures. Figure Distribution Outages by Cause (% of total customer minutes) Trees or limbs, preventable 21% Unknown 8% Underground dig-in 1% Bird or animal 6% Trees or limbs, non-preventable 28% Equipment failure 14% Other 1% Motor vehicle 19% Electric System Reliability Report

27 Figure 6-4 Five-Year Average Distribution Outages by Cause (% of total customer minutes, ) Bird or animal 2% Trees or limbs, preventable 16% Unknown 10% Equipment failure 12% Motor vehicle 15% Lightning 2% Trees or limbs, non-preventable 39% Other 6% Trees or limbs, man-caused 1% 2015 Electric System Reliability Report 27

28 6.2.2 Explanation of Equipment Failure Category Equipment failures may include any component of the distribution system, from substation breakers or primary overhead conductor, to fuses, transformers, insulators, and secondary service conductors. Figure 6-5 shows the number of equipment failures by category. In the top ten categories, equipment failed 189 times in For comparison, Figure 6-6 shows the five-year average of the number of equipment failures by category; in the top ten categories, equipment failed 256 times annually, on average. The number of equipment failures in most categories for 2015 was less than the five-year average. Figure 6-5 Equipment Failures Figure 6-6 Equipment Failures Five-Year Average ( ) Electric System Reliability Report

29 6.3 The Cause of Outages on the Twenty Circuits with the Greatest Number of Outages Table 6.1 identifies the twenty circuits that had the greatest number of distribution outages in To determine where to direct efforts to reduce the number of outages, it is necessary to know what caused the outages. Figure 6.7 shows the number of outages that were a result of each type of outage cause. Figure 6.8 shows the customer SAIDI minutes by outage cause for the same outages as in Figure 6.7. A noticeable change is evident in both the number of, and SAIDI for, non-preventable tree-related outages. This may be explained by the change in recording practice: outages that would have been excluded because they occurred during wind events are now recorded and included in the ORS statistics. Table 6-1 The Twenty Circuits that had the greatest number of distribution outages in 2015 Substation Circuit Number Outage Count East Arlington Goldbar North Mountain Clearview Three Lakes Granite Falls Stimson s Crossing Sultan Granite Falls North Stanwood Portage Village East Arlington Lake Chaplain Lake Goodwin Three Lakes Quil-Ceda Woods Creek Clearview East Arlington Three Lakes Turners Corner Woods Creek Electric System Reliability Report 29

30 Figure 6-7 Cause of Outages on the Twenty Circuits with the greatest number of distribution outages Other utility Underground dig-in Other Lightning Motor vehicle Fatigued fuse Unknown Bird or animal Equipment Failure Trees or limbs, preventable Trees non-preventable Number of Outages Electric System Reliability Report

31 Figure 6-8 SAIDI by Outage Cause for the Twenty Circuits with the greatest number of distribution outages Underground dig-in Fatigued fuse Other utility Lightning Other Bird or animal Equipment Failure Unknown Motor vehicle Trees nonpreventable Trees or limbs, preventable SAIDI in Minutes 2015 Electric System Reliability Report 31

32 6.4 Tree-Related Outages Table 6.2 lists all circuits that experienced a tree-caused outage in 2015, sorted by the total number of outages. Tree-caused outages are further classified as preventable, non-preventable, or human-caused. Preventable outage data is used to identify areas that may benefit from increased tree trimming. Table Tree-Related Outages Human Caused Non- Preventable Substation Circuit Total Goldbar Granite Falls North Mountain East Arlington Three Lakes Granite Falls Three Lakes Lake Chaplain Clearview Sultan Sultan West Monroe Woods Creek East Arlington Hartford North Stanwood South Camano Three Lakes East Arlington Granite Falls North Mountain Portage South Camano Stimson's Crossing Granite Falls Granite Falls Lake Goodwin Quil-Ceda Village Wallace River Woods Creek Clearview East Marysville Fifty-Second Street Preventable Electric System Reliability Report

33 Substation Circuit Total Human Caused Non- Preventable Preventable Goldbar Lake Goodwin Lake Stevens Oso Richmond Park South Camano Sunset Turners Corner Ballinger Canyon Park Cascade East Arlington Floral Hills Fobes Frontier Gibson Granite Falls Granite Falls Hartford Hartford Lake Goodwin Meadowdale North Camano North Stanwood Oso Park Ridge Park Ridge Park Ridge Perrinville Picnic Point Pinehurst Snohomish Sultan Tulalip Tulalip Turners Corner Village West Monroe Woods Creek Brier Bunk Foss Bunk Foss Electric System Reliability Report 33

34 Substation Circuit Total Human Caused Non- Preventable Preventable Casino Clearview East Arlington Edgecomb Fifty-Second Street Floral Hills Floral Hills Fobes Fobes Gibson Gibson Granite Falls Hartford Hartford Hilton Lake Lake Chaplain Lake Goodwin Lake Serene Maplewood Maplewood Mariner Martha Lake Martha Lake Meadowdale Mountlake Terrace Murphys Corner North Camano North Mountain North Stanwood Park Ridge Perrinville Picnic Point Polaris Portage Portage Richmond Park Silver Lake Snohomish South Camano Stimson's Crossing Sunset Sunset Electric System Reliability Report

35 Substation Circuit Total Human Caused Non- Preventable Preventable Tulalip Tulalip Turners Corner West Monroe Westgate Woods Creek Figures 6-9, 6-10, and 6-11 show five years tree-related outage count, SAIDI, and CAIDI, respectively, for the distribution system as a whole. Figure 6-9 Tree-related outage count over the past five years 600 Tree-related Outage Count 500 Number of outages non-preventable preventable human-caused 2015 Electric System Reliability Report 35

36 Figure 6-10 Tree-related SAIDI over the past five years Tree-related SAIDI SAIDI (Customer minutes) non-preventable preventable human-caused Figure 6-11 Tree-related CAIDI over the past five years Tree-related CAIDI CAIDI (Customer minutes) non-preventable preventable human-caused Electric System Reliability Report

37 6.5 Underground Cable-Related Outages Figure 6-12 shows the trending of underground primary and secondary cable failure over the past ten years. The District is involved in an ongoing underground cable testing, injection, and replacement program. Started in 1997, the program was expanded in Cable failures are continuing to trend downwards. The 2014 program goal to inject the Hat Island cable was deferred until Contract bid documents were completed and sent out to bid in December with a planned award in Q Approximately 44.6 miles of depreciated-condition cable was replaced in Cable replacement primarily targets bare concentric neutral cable and feeder cable assets installed from 1962 through 1981 that have shown an increased rate of insulation failure and significant neutral corrosion. The remaining feeder class cables installed between 1965 and 1981 were a higher priority in 2015, and will be a higher priority in future program budgets. Neutral testing was completed for 128 miles in Remaining bare concentric neutral cable systems installed from 1982 through 1988 which have not yet shown increased rate of insulation failures will have the neutral tested to identify cables with significant corrosion that should be designed for replacement. The District injected 1.5 miles of direct-buried 1970 feeder cable at Clearview Substation in 2015 to extend their life and defer replacement until the Substation is rebuilt in 15 years. The 2015 program goal to inject the Hat Island cable was delayed by receiving no bids on a Request For Quote for the project, and by difficulty with the injection process on the similar BC Hydro Cortez Island cable. The District is currently considering alternative plans for the cable, with the first step being the low cost alternative of reducing the voltage on the lightly loaded cable to 4 kv. This approach has been proven to extend the life of these types of cable by 15 years or more. Figure 6-12 Underground primary and secondary cable failure outages Cable Failure Outages Number of Outages U/G Primary Cable U/G Secondary (District-Owned) U/G Secondary (Customer-Owned) 2015 Electric System Reliability Report 37

38 6.6 Distribution Automation In 2009, the District was awarded federal funding as part of a Smart Grid Investment Grant (SGIG). The District s SGIG project includes distribution automation (DA), which is intended to perform in concert with other SGIG components, such as a Distribution Management System, installation of fiber optic cable, and substation automation. The District s DA effort includes installation of automated, telemetered line equipment on ten distribution circuits, fed from five substations. The pilot project is ongoing. The circuits for the pilot project were chosen based on several criteria, one of which was reliability performance. Measurement of the reliability indices in the DA implementation area will help to determine the overall effect of DA installations on the distribution system. The ten DA circuits are listed in Table 6-3. Reliability performance comparisons for those ten circuits to the system as a whole are shown in Table 6-4. Comparisons are made between the DA circuits and the entire system for the periods of October through March, and April through September. Table 6-3 Distribution Automation Circuits Substation Feeder Number Lake Goodwin 0379 Lake Goodwin 0380 Lake Goodwin 0381 Lake Goodwin 0382 Tulalip 0507 Tulalip 0508 Stimson Crossing 3091 Stimson Crossing 3093 Quil-Ceda 3178 Village Electric System Reliability Report

39 Table 6-4 DA Study area reliability indices versus District s entire system Reporting period to to to to to to to to to to DA area SAIDI DA area CAIDI DA area SAIFI System SAIDI System CAIDI System SAIFI Electric System Reliability Report 39

40 Appendix A 2015 Substation and Circuit Statistics Table A-1 Table A-2 Table A-3 Table A-4 Table A-5 The twenty (20) circuits with the highest outage count The twenty (20) circuits with the highest SAIDI value The twenty (20) circuits with the highest CAIDI value The twenty (20) circuits with the highest SAIFI value Reliability statistics for all District substations and circuits. Values are provided for both 2015 and the five-year weighted average, covering the period from 2010 through Weighting is based on the number of customers served for each year. Figure A1 Figure A2 Figure A3 Map depicting the 2015 SAIDI circuit values graphically Map depicting the 2015 SAIFI circuit values graphically Map depicting the 2015 CAIDI circuit values graphically These tables and figures include outages that occurred on both the transmission system and on the distribution system. They do not include outages that occurred during declared major events Electric System Reliability Report

41 Table A1. The Twenty Circuits with the Highest Outage Count Substation Annual Year: 2015 Five-Year Average: 2010 to 2014 Transmission and Distribution Outages, Major Event Outages Not Included Circuit Number Number of Customers Number of Outages Customer Outage Minutes Circuit SAIDI Circuit CAIDI East Arlington 2617 Annual 1, , Yr. Avg. 1, , Goldbar 554 Annual 2, ,688, Yr. Avg. 2, , North Mountain 2514 Annual 1, , Yr. Avg. 1, , Clearview 587 Annual 1, , Yr. Avg. 1, , Three Lakes 1820 Annual 1, , Yr. Avg. 1, , Granite Falls 810 Annual 1, ,068, Yr. Avg. 1, , Stimson s Crossing 3091 Annual 1, , Yr. Avg. 1, , Sultan 1595 Annual 2, , Yr. Avg. 2, , Granite Falls 4615 Annual 1, , Yr. Avg. 1, , North Stanwood 999 Annual 2, , Yr. Avg. 2, , Portage 3504 Annual 1, , Yr. Avg. 1, , Village 4305 Annual 1, , Yr. Avg. 1, , East Arlington 988 Annual 1, , Yr. Avg. 1, , Lake Chaplain 2036 Annual , Yr. Avg , Lake Goodwin 379 Annual 1, , Yr. Avg. 1, , Three Lakes 1818 Annual , Yr. Avg , Quil-Ceda 3178 Annual 1, , Yr. Avg. 1, , Woods Creek 1809 Annual 1, , Yr. Avg. 1, , Clearview 586 Annual 1, , Yr. Avg. 1, , East Arlington 2618 Annual 1, , Yr. Avg. 1, , Three Lakes 1819 Annual 1, , Yr. Avg. 1, , Turners Corner 1429 Annual 1, , Yr. Avg. 1, , Woods Creek 1808 Annual 1, , Yr. Avg. 1, , The average values are weighted by the number of customers served in each year. Circuit SAIFI 2015 Electric System Reliability Report 41

42 Table A2. The Twenty Circuits with the Highest SAIDI Value Annual Year: 2015 Five-Year Average: 2010 to 2014 Transmission and Distribution Outages, Major Event Outages Not Included Circuit Number of Number of Customer Outage Circuit Circuit Substation Circuit SAIDI Number Customers Outages Minutes CAIDI SAIFI Goldbar 554 Annual 2, ,688, Year Average 2, , Granite Falls 810 Annual 1, ,068,533 1, Year Average 1, , Lake Chaplain 2036 Annual ,717 1, Year Average , South Camano 1533 Annual 1, , Year Average 1, , North Mountain 2514 Annual 1, , Year Average 1, , North Camano 315 Annual , Year Average , Granite Falls 809 Annual 1, , Year Average 1, , Sultan 1593 Annual , Year Average , Three Lakes 1819 Annual 1, , Year Average 1, , Granite Falls 4615 Annual 1, , Year Average 1, , East Arlington 2617 Annual 1, , Year Average 1, , North Mountain 2515 Annual , Year Average , Oso 1310 Annual , Year Average , Polaris 4502 Annual 1, , Year Average 1, , Three Lakes 1820 Annual 1, , Year Average 1, , Brier 503 Annual 1, , Year Average 1, , North Stanwood 3204 Annual 2, , Year Average 1, , North Mountain 2516 Annual Year Average Hartford 3117 Annual , Year Average , Polaris 4500 Annual , Year Average , Polaris 4500 Annual 8 2 2, Year Average Electric System Reliability Report

43 Table A3. The Twenty Circuits with the Highest CAIDI Value Substation Circuit Number Annual Year: 2015 Five-Year Average: 2010 to 2014 Transmission and Distribution Outages, Major Event Outages Not Included Number of Customers Number of Outages Customer Outage Minutes Circuit SAIDI Circuit CAIDI Sunset 5212 Annual 1, , , Circuit SAIFI 5 Year Average 1, , Mariner 3347 Annual 1, , , Year Average 1, , Stimson's Crossing 3092 Annual , Year Average , Woods Creek 1809 Annual 1, , Year Average 1, , Casino 308 Annual 1, , Year Average 1, , Turners Corner 1431 Annual , Year Average , Woods Creek 1810 Annual , Year Average , Picnic Point 1415 Annual 1, , Year Average 1, , Lynnwood 726 Annual , Year Average , Fifty-Second Street 184 Annual 1, , Year Average 1, , Richmond Park 232 Annual , Year Average , Richmond Park 2048 Annual , Year Average , Stimson's Crossing 3093 Annual , Year Average , Alderwood 117 Annual , Year Average , Westgate 406 Annual 1, Year Average 1, , Turners Corner 1430 Annual , Year Average , Granite Falls 810 Annual 1, ,068, Year Average 1, , Gibson 2899 Annual , Year Average , Tulalip 505 Annual , Year Average , Brier 502 Annual 1, , Year Average , Electric System Reliability Report 43

44 Table A4. The Twenty Circuits with the Highest SAIFI Value Annual Year: 2015 Five-Year Average: 2010 to 2014 Transmission and Distribution Outages, Major Event Outages Not Included Circuit Number of Number of Customer Circuit Circuit Circuit Substation Number Customers Outages Outage Minutes SAIDI CAIDI SAIFI Granite Falls 4615 Annual 1, , Year Average 1, , Lake Chaplain 2036 Annual , Year Average , South Camano 1533 Annual 1, , Year Average 1, , Three Lakes 1819 Annual 1, , Year Average 1, , Polaris 4502 Annual 1, , Year Average 1, , Three Lakes 1821 Annual , Year Average , North Mountain 2514 Annual 1, , Year Average 1, , Goldbar 554 Annual 2, ,688, Year Average 2, , Canyon Park 1096 Annual 1, , Year Average 1, , Gibson 2898 Annual 1, , Year Average 1, , North Camano 315 Annual , Year Average , Granite Falls 809 Annual 1, , Year Average 1, , Oso 1310 Annual , Year Average , Hartford 3117 Annual , Year Average , Sultan 1595 Annual 2, , Year Average 2, , Sultan 1593 Annual , Year Average , Portage 3504 Annual 1, , Year Average 1, , Three Lakes 1820 Annual 1, , Year Average 1, , North Mountain 2515 Annual , Year Average , East Arlington 2618 Annual 1, , Year Average 1, , Electric System Reliability Report

45 Table A5. Substation & Circuit Statistics Annual Year: 2015 Five Year Average 2010 to 2014 Transmission and Distribution Outages, Major Event Outages Not Included Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Alderwood 116 Annual Yr. Avg , Alderwood 117 Annual , Yr. Avg , Alderwood 132 Annual 1, Yr. Avg. 1, , Alderwood 141 Annual Yr. Avg , Alderwood Annual 3, , Substation 5 Yr. Avg. 3, , Ballinger 258 Annual , Yr. Avg , Ballinger 259 Annual Yr. Avg , Ballinger 260 Annual 1, , Yr. Avg. 1, , Ballinger 261 Annual 1, , Yr. Avg. 1, , Ballinger Annual 3, , Substation 5 Yr. Avg. 3, , Brier 501 Annual 1, Yr. Avg. 1, , Brier 502 Annual 1, , Yr. Avg , Brier 503 Annual 1, , Yr. Avg. 1, , Brier 504 Annual 1, , Yr. Avg. 1, , Brier Annual 5, , Substation 5 Yr. Avg. 5, , Electric System Reliability Report 45

46 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Bunk Foss 4111 Annual Yr. Avg , Bunk Foss 4112 Annual Yr. Avg , Bunk Foss 4113 Annual , Yr. Avg , Bunk Foss 4114 Annual , Yr. Avg , Bunk Foss Annual 2, , Substation 5 Yr. Avg. 2, , Canyon Park 1093 Annual 1, , Yr. Avg. 1, , Canyon Park 1094 Annual 1, , Yr. Avg. 1, , Canyon Park 1095 Annual 1, , Yr. Avg. 1, , Canyon Park 1096 Annual 1, , Yr. Avg. 1, , Canyon Park 3488 Annual , Yr. Avg , Canyon Park Annual 5, ,130, Substation 5 Yr. Avg. 4, , Cascade 2087 Annual 1, Yr. Avg. 1, , Cascade 2088 Annual 3, , Yr. Avg. 3, , Cascade 2089 Annual 1, Yr. Avg. 1, , Cascade 2090 Annual 2, , Yr. Avg. 2, , Cascade Annual 10, , Substation 5 Yr. Avg. 9, , Electric System Reliability Report

47 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Casino 308 Annual 1, , Yr. Avg. 1, , Casino 309 Annual , Yr. Avg , Casino 310 Annual 1, , Yr. Avg. 1, , Casino 311 Annual 1, , Yr. Avg. 1, , Casino Annual 3, , Substation 5 Yr. Avg. 3, , Central Marysville 1419 Annual 1, Yr. Avg. 1, , Central Marysville 1420 Annual 1, Yr. Avg. 1, , Central Marysville 1421 Annual 1, , Yr. Avg. 1, , Central Marysville 1422 Annual 1, , Yr. Avg. 1, , Central Marysville Annual 5, , Substation 5 Yr. Avg. 5, , Clearview 584 Annual 2, Yr. Avg. 1, , Clearview 585 Annual 1, , Yr. Avg. 1, , Clearview 586 Annual 1, , Yr. Avg. 1, , Clearview 587 Annual 1, , Yr. Avg. 1, , Clearview Annual 6, , Substation 5 Yr. Avg. 6, ,224, Electric System Reliability Report 47

48 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Delta 3653 Annual Yr. Avg , Delta 3654 Annual Yr. Avg Delta 3655 Annual Yr. Avg , Delta 3656 Annual Yr. Avg , Delta Annual 1, Substation 5 Yr. Avg. 1, , East Arlington 986 Annual 1, Yr. Avg. 1, , East Arlington 987 Annual Yr. Avg , East Arlington 988 Annual 1, , Yr. Avg. 1, , East Arlington 989 Annual Yr. Avg , East Arlington 2617 Annual 1, , Yr. Avg. 1, , East Arlington 2618 Annual 1, , Yr. Avg. 1, , East Arlington 2619 Annual 1, , Yr. Avg. 1, , East Arlington 2620 Annual , Yr. Avg , East Arlington Annual 9, ,367, Substation 5 Yr. Avg. 8, ,285, Electric System Reliability Report

49 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI East Marysville 2 Annual , Yr. Avg. 1, , East Marysville 37 Annual 1, , Yr. Avg. 1, , East Marysville 38 Annual 1, , Yr. Avg. 1, , East Marysville 70 Annual 1, , Yr. Avg. 1, , East Marysville 115 Annual 1, Yr. Avg. 1, , East Marysville 5203 Annual 1, Yr. Avg. 1, East Marysville 5204 Annual 1, , Yr. Avg. 1, , East Marysville Annual 10, , Substation 5 Yr. Avg. 9, , Edgecomb 4831 Annual , Yr. Avg Edgecomb 4832 Annual 1, , Yr. Avg. 1, , Edgecomb 4833 Annual 1, , Yr. Avg. 1, , Edgecomb 4834 Annual , Yr. Avg , Edgecomb Annual 3, , Substation 4 Yr. Avg. 3, , Electric System Reliability Report 49

50 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Esperance 687 Annual 1, , Yr. Avg. 1, , Esperance 688 Annual 1, , Yr. Avg. 1, , Esperance 689 Annual 1, , Yr. Avg. 1, , Esperance 1597 Annual 1, Yr. Avg. 1, , Esperance Annual 5, , Substation 5 Yr. Avg. 5, , Everett 100 Annual Yr. Avg , Everett 101 Annual Yr. Avg , Everett 112 Annual Yr. Avg , Everett 113 Annual , Yr. Avg , Everett 118 Annual 1, Yr. Avg. 1, Everett 119 Annual 1, , Yr. Avg. 1, , Everett 121 Annual Yr. Avg , Everett 122 Annual Yr. Avg , Everett Annual 5, , Substation 5 Yr. Avg. 4, , Electric System Reliability Report

51 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Fifty-Second 183 Annual Street 5 Yr. Avg , Fifty-Second 184 Annual 1, , Street 5 Yr. Avg. 1, , Fifty-Second 185 Annual , Street 5 Yr. Avg , Fifty-Second 186 Annual , Street 5 Yr. Avg , Fifty-Second Street Annual 3, , Substation 5 Yr. Avg. 3, , Fitzgerald 5508 Annual , Yr. Avg Fitzgerald 5509 Annual Yr. Avg Fitzgerald 5510 Annual , Yr. Avg Fitzgerald 5511 Annual Yr. Avg Fitzgerald Annual 3, , Substation 5 Yr. Avg. 3, , Five Corners 1282 Annual 1, , Yr. Avg. 1, , Five Corners 1283 Annual 1, , Yr. Avg. 1, , Five Corners 1284 Annual , Yr. Avg , Five Corners 1285 Annual 1, , Yr. Avg. 1, , Five Corners Annual 5, , Substation 5 Yr. Avg. 5, , Floral Hills 2062 Annual 1, , Yr. Avg. 1, , Floral Hills 2063 Annual 2, , Yr. Avg. 2, , Floral Hills 2064 Annual 1, , Yr. Avg. 1, , Floral Hills 2065 Annual 2, Yr. Avg. 2, , Floral Hills Annual 7, , Substation 5 Yr. Avg. 7, , Electric System Reliability Report 51

52 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Fobes 398 Annual 1, , Yr. Avg. 1, , Fobes 399 Annual 1, Yr. Avg , Fobes 400 Annual 1, , Yr. Avg. 1, , Fobes 401 Annual Yr. Avg , Fobes Annual 4, , Substation 5 Yr. Avg. 4, , Frontier 533 Annual 1, , Yr. Avg. 1, , Frontier 534 Annual 1, Yr. Avg. 2, , Frontier 535 Annual 2, , Yr. Avg. 2, , Frontier 536 Annual 1, , Yr. Avg. 1, , Frontier Annual 6, , Substation 5 Yr. Avg. 7, , Gibson 2897 Annual 2, , Yr. Avg. 2, , Gibson 2898 Annual 1, , Yr. Avg. 1, , Gibson 2899 Annual , Yr. Avg , Gibson 2900 Annual 1, , Yr. Avg. 1, , Gibson Annual 6, , Substation 5 Yr. Avg. 6, , Electric System Reliability Report

53 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Glenwood 592 Annual 1, , Yr. Avg. 1, , Glenwood 593 Annual 1, , Yr. Avg. 1, , Glenwood 594 Annual 2, , Yr. Avg. 2, , Glenwood 595 Annual , Yr. Avg , Glenwood Annual 5, , Substation 5 Yr. Avg. 5, , Goldbar 554 Annual 2, ,688, Yr. Avg. 2, , Goldbar 555 Annual , Yr. Avg , Goldbar Annual 2, ,757, Substation 5 Yr. Avg. 2, ,080, Granite Falls 808 Annual , Yr. Avg , Granite Falls 809 Annual 1, , Yr. Avg. 1, , Granite Falls 810 Annual 1, ,068, Yr. Avg. 1, , Granite Falls 811 Annual , Yr. Avg , Granite Falls 4612 Annual , Yr. Avg , Granite Falls 4613 Annual , Yr. Avg , Granite Falls 4614 Annual ,836 2, Yr. Avg , Granite Falls 4615 Annual 1, , Yr. Avg. 1, , Granite Falls Annual 6, ,316, Substation 5 Yr. Avg. 6, ,722, Electric System Reliability Report 53

54 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Harbour Pointe 2277 Annual 1, Yr. Avg. 1, Harbour Pointe 2278 Annual Yr. Avg , Harbour Pointe 2279 Annual Yr. Avg , Harbour Pointe 2280 Annual Yr. Avg Harbour Pointe 4674 Annual Yr. Avg , Harbour Pointe 4675 Annual Yr. Avg Harbour Pointe 4677 Annual , Yr. Avg , Harbour Pointe Annual 5, , Substation 5 Yr. Avg. 4, , Hardeson 4557 Annual Yr. Avg Hardeson 4558 Annual Yr. Avg Hardeson 4559 Annual Yr. Avg , Hardeson Annual Substation 5 Yr. Avg , Electric System Reliability Report

55 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Hartford 3117 Annual , Yr. Avg , Hartford 3118 Annual , Yr. Avg , Hartford 3119 Annual , Yr. Avg , Hartford 3120 Annual 1, , Yr. Avg. 1, , Hartford 3327 Annual , Yr. Avg , Hartford Annual 4, , Substation 5 Yr. Avg. 5, , Hilton Lake 497 Annual 1, , Yr. Avg. 1, , Hilton Lake 498 Annual Yr. Avg , Hilton Lake 499 Annual 2, , Yr. Avg. 2, , Hilton Lake 500 Annual 2, Yr. Avg. 2, , Hilton Lake Annual 6, , Substation 5 Yr. Avg. 6, , Kellogg Marsh 904 Annual 1, , Yr. Avg. 1, , Kellogg Marsh 905 Annual 2, Yr. Avg. 1, , Kellogg Marsh 906 Annual 1, , Yr. Avg. 1, , Kellogg Marsh 907 Annual Yr. Avg , Kellogg Marsh Annual 5, , Substation 5 Yr. Avg. 5, , Electric System Reliability Report 55

56 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Lake Chaplain 2034 Annual , Yr. Avg , Lake Chaplain 2035 Annual Yr. Avg Lake Chaplain 2036 Annual , Yr. Avg , Lake Chaplain Annual , Substation 5 Yr. Avg , Lake Goodwin 379 Annual 1, , Yr. Avg. 1, , Lake Goodwin 380 Annual 1, , Yr. Avg. 1, , Lake Goodwin 381 Annual 1, , Yr. Avg. 1, , Lake Goodwin 382 Annual 1, Yr. Avg , Lake Goodwin 383 Annual 1, , Yr. Avg. 1, , Lake Goodwin Annual 5, , Substation 5 Yr. Avg. 5, , Lake Serene 337 Annual 1, , Yr. Avg. 1, , Lake Serene 338 Annual 1, , Yr. Avg. 1, , Lake Serene 339 Annual 1, Yr. Avg. 1, , Lake Serene 340 Annual 2, , Yr. Avg. 2, , Lake Serene Annual 6, , Substation 5 Yr. Avg. 6, , Electric System Reliability Report

57 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Lake Stevens 124 Annual 1, , Yr. Avg. 1, , Lake Stevens 125 Annual 2, Yr. Avg. 2, , Lake Stevens 273 Annual Yr. Avg , Lake Stevens 274 Annual 1, , Yr. Avg. 1, , Lake Stevens Annual 6, , Substation 5 Yr. Avg. 5, , Lynnwood 724 Annual 1, , Yr. Avg. 1, , Lynnwood 725 Annual , Yr. Avg , Lynnwood 726 Annual , Yr. Avg , Lynnwood 727 Annual 1, , Yr. Avg. 1, , Lynnwood 4867 Annual Yr. Avg Lynnwood Annual 5, , Substation 5 Yr. Avg. 4, , Maplewood 343 Annual 1, , Yr. Avg. 1, , Maplewood 344 Annual 1, Yr. Avg. 1, , Maplewood 345 Annual , Yr. Avg , Maplewood 346 Annual , Yr. Avg , Maplewood Annual 4, , Substation 5 Yr. Avg. 4, , Electric System Reliability Report 57

58 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Mariner 3346 Annual Yr. Avg , Mariner 3347 Annual 1, , , Yr. Avg. 1, , Mariner 3348 Annual 1, , Yr. Avg. 1, , Mariner 3349 Annual Yr. Avg Mariner 3391 Annual 1, , Yr. Avg. 1, , Mariner Annual 4, , Substation 5 Yr. Avg. 4, , Martha Lake 73 Annual 2, , Yr. Avg. 1, , Martha Lake 74 Annual , Yr. Avg ,719 2, Martha Lake 251 Annual , Yr. Avg , Martha Lake 466 Annual 1, , Yr. Avg. 1, , Martha Lake Annual 5, ,085, Substation 5 Yr. Avg. 4, , Meadowdale 1837 Annual 1, , Yr. Avg. 1, , Meadowdale 1838 Annual 1, , Yr. Avg. 1, , Meadowdale 1839 Annual 1, Yr. Avg. 1, , Meadowdale 1840 Annual , Yr. Avg , Meadowdale Annual 4, , Substation 5 Yr. Avg. 4, , Electric System Reliability Report

59 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Mountlake 133 Annual 1, , Terrace 5 Yr. Avg. 1, , Mountlake 134 Annual 1, , Terrace 5 Yr. Avg. 1, , Mountlake 135 Annual 1, , Terrace 5 Yr. Avg. 1, , Mountlake 136 Annual 2, , Terrace 5 Yr. Avg. 1, , Mountlake Terrace Annual 6, , Substation 5 Yr. Avg. 6, , Mukilteo 128 Annual 1, , Yr. Avg. 1, , Mukilteo 129 Annual , Yr. Avg , Mukilteo 600 Annual 1, , Yr. Avg. 1, , Mukilteo 4523 Annual , Yr. Avg , Mukilteo Annual 4, , Substation 5 Yr. Avg. 4, , Murphys Corner 1748 Annual 1, , Yr. Avg. 1, , Murphys Corner 1749 Annual 1, , Yr. Avg. 1, , Murphys Corner 1750 Annual Yr. Avg , Murphys Corner 1751 Annual , Yr. Avg , Murphys Corner Annual 4, , Substation 5 Yr. Avg. 4, , Electric System Reliability Report 59

60 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI North Alderwood 509 Annual Yr. Avg , North Alderwood 510 Annual Yr. Avg , North Alderwood 511 Annual Yr. Avg North Alderwood 512 Annual , Yr. Avg North Alderwood Annual , Substation 5 Yr. Avg , North Camano 313 Annual , Yr. Avg , North Camano 314 Annual Yr. Avg , North Camano 315 Annual , Yr. Avg , North Camano 316 Annual 1, , Yr. Avg. 1, , North Camano Annual 2, , Substation 5 Yr. Avg. 3, , North Creek 1410 Annual 1, , Yr. Avg. 1, , North Creek 1411 Annual 1, Yr. Avg. 1, , North Creek 1412 Annual 1, Yr. Avg. 1, , North Creek 1413 Annual 1, , Yr. Avg. 1, , North Creek 3733 Annual Yr. Avg North Creek Annual 6, , Substation 5 Yr. Avg. 6, , Electric System Reliability Report

61 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI North Marysville 142 Annual , Yr. Avg , North Marysville 143 Annual , Yr. Avg , North Marysville 144 Annual 1, , Yr. Avg. 1, , North Marysville 254 Annual , Yr. Avg , North Marysville Annual 2, , Substation 5 Yr. Avg. 2, , North Mountain 2514 Annual 1, , Yr. Avg. 1, , North Mountain 2515 Annual , Yr. Avg , North Mountain 2516 Annual Yr. Avg North Mountain Annual 2, ,031, Substation 5 Yr. Avg. 1, , North Stanwood 996 Annual , Yr. Avg , North Stanwood 997 Annual , Yr. Avg , North Stanwood 998 Annual 1, , Yr. Avg. 1, , North Stanwood 999 Annual 2, , Yr. Avg. 2, , North Stanwood 3204 Annual 2, , Yr. Avg. 1, , North Stanwood Annual 6, ,117, Substation 5 Yr. Avg. 6, , Electric System Reliability Report 61

62 Circuit # of Number of Customer Substation Numbers Customers Outages Minutes SAIDI CAIDI SAIFI Norton Avenue 588 Annual , Yr. Avg , Norton Avenue 589 Annual 1, , Yr. Avg. 1, , Norton Avenue 590 Annual 1, Yr. Avg. 1, , Norton Avenue 591 Annual , Yr. Avg , Norton Avenue Annual 3, , Substation 5 Yr. Avg. 3, , Olivia Park 2576 Annual 1, , Yr. Avg. 1, Olivia Park 2577 Annual , Yr. Avg , Olivia Park 2578 Annual 1, , Yr. Avg. 1, , Olivia Park 2579 Annual 1, , Yr. Avg. 1, , Olivia Park Annual 4, , Substation 5 Yr. Avg. 4, , Oso 1309 Annual , Yr. Avg , Oso 1310 Annual , Yr. Avg , Oso Annual , Substation 5 Yr. Avg , Electric System Reliability Report

63 Circuit # of Number of Customer Substation Numbers Customers Outages Minutes SAIDI CAIDI SAIFI Paine Field 385 Annual Yr. Avg , Paine Field 386 Annual Yr. Avg , Paine Field 387 Annual 1, , Yr. Avg. 1, , Paine Field 388 Annual Yr. Avg Paine Field 1729 Annual 1, , Yr. Avg. 1, , Paine Field 1730 Annual 1, , Yr. Avg. 1, , Paine Field 1731 Annual 2, , Yr. Avg. 2, , Paine Field 1732 Annual Yr. Avg , Paine Field Annual 8, , Substation 5 Yr. Avg. 8, , Park Ridge 2319 Annual , Yr. Avg. 1, , Park Ridge 2320 Annual 1, , Yr. Avg , Park Ridge 2321 Annual 1, , Yr. Avg. 1, , Park Ridge 2322 Annual , Yr. Avg , Park Ridge 4183 Annual , Yr. Avg , Park Ridge Annual 5, , Substation 5 Yr. Avg. 5, , Electric System Reliability Report 63

64 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Perrinville 92 Annual , Yr. Avg , Perrinville 93 Annual 1, , Yr. Avg. 1, , Perrinville 126 Annual 1, , Yr. Avg. 1, , Perrinville 221 Annual 1, , Yr. Avg. 1, , Perrinville Annual 4, , Substation 5 Yr. Avg. 4, , Picnic Point 1414 Annual , Yr. Avg , Picnic Point 1415 Annual 1, , Yr. Avg. 1, , Picnic Point 1416 Annual 1, Yr. Avg. 1, , Picnic Point 1417 Annual Yr. Avg , Picnic Point Annual 3, , Substation 5 Yr. Avg. 3, , Pinehurst 147 Annual , Yr. Avg , Pinehurst 148 Annual 1, , Yr. Avg. 1, , Pinehurst 149 Annual 1, , Yr. Avg. 1, , Pinehurst 220 Annual 1, , Yr. Avg , Pinehurst 3350 Annual 1, , Yr. Avg. 1, , Pinehurst Annual 6, , Substation 5 Yr. Avg. 6, , Electric System Reliability Report

65 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Polaris 4500 Annual , Yr. Avg , Polaris 4501 Annual 1, , Yr. Avg. 1, , Polaris 4502 Annual 1, , Yr. Avg. 1, , Polaris 4503 Annual 8 2 2, Yr. Avg Polaris Annual 3, ,197, Substation 5 Yr. Avg. 3, , Portage 3502 Annual Yr. Avg , Portage 3503 Annual , Yr. Avg , Portage 3504 Annual 1, , Yr. Avg. 1, , Portage 3505 Annual 1, , Yr. Avg. 1, , Portage Annual 2, , Substation 5 Yr. Avg. 2, , Quil-Ceda 3177 Annual , Yr. Avg , Quil-Ceda 3178 Annual 1, , Yr. Avg. 1, , Quil-Ceda 3179 Annual Yr. Avg Quil-Ceda 3180 Annual 1, , Yr. Avg. 1, , Quil-Ceda Annual 3, , Substation 5 Yr. Avg. 2, , Electric System Reliability Report 65

66 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Richmond Park 232 Annual , Yr. Avg , Richmond Park 233 Annual , Yr. Avg , Richmond Park 2048 Annual , Yr. Avg , Richmond Park 5217 Annual , Yr. Avg , Richmond Park Annual 2, , Substation 5 Yr. Avg. 2, , Silver Lake 239 Annual 1, Yr. Avg. 1, , Silver Lake 240 Annual 1, , Yr. Avg. 1, , Silver Lake 253 Annual 1, , Yr. Avg. 1, , Silver Lake 267 Annual , Yr. Avg , Silver Lake 290 Annual , Yr. Avg , Silver Lake Annual 6, , Substation 5 Yr. Avg. 5, , Smokey Point 1507 Annual , Yr. Avg , Smokey Point 1508 Annual , Yr. Avg , Smokey Point 1509 Annual 1, , Yr. Avg. 1, , Smokey Point 1510 Annual , Yr. Avg , Smokey Point Annual 3, , Substation 5 Yr. Avg. 3, , Electric System Reliability Report

67 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Snohomish 103 Annual Yr. Avg , Snohomish 104 Annual , Yr. Avg , Snohomish 123 Annual 1, , Yr. Avg. 1, , Snohomish 151 Annual , Yr. Avg , Snohomish Annual 3, , Substation 5 Yr. Avg. 3, , South Camano 1530 Annual , Yr. Avg. 1, , South Camano 1531 Annual , Yr. Avg , South Camano 1532 Annual 1, , Yr. Avg. 1, , South Camano 1533 Annual 1, , Yr. Avg. 1, , South Camano Annual 3, , Substation 5 Yr. Avg. 4, ,472, Stimson's 3090 Annual , Crossing 5 Yr. Avg , Stimson's 3091 Annual 1, , Crossing 5 Yr. Avg. 1, , Stimson's 3092 Annual , Crossing 5 Yr. Avg , Stimson's 3093 Annual , Crossing 5 Yr. Avg , Stimson's Crossing Annual 2, , Substation 5 Yr. Avg. 2, , Electric System Reliability Report 67

68 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Sultan 1593 Annual , Yr. Avg , Sultan 1594 Annual , Yr. Avg , Sultan 1595 Annual 2, , Yr. Avg. 2, , Sultan 1596 Annual , Yr. Avg , Sultan 5004 Annual Yr. Avg Sultan Annual 3, , Substation 5 Yr. Avg. 3, , Sunset 5208 Annual 1, , Yr. Avg. 1, , Sunset 5209 Annual , Yr. Avg , Sunset 5210 Annual , Yr. Avg , Sunset 5211 Annual Yr. Avg , Sunset 5212 Annual 1, , , Yr. Avg. 1, , Sunset Annual 4, , Substation 4 Yr. Avg. 3, , Tenth Street 298 Annual 1, Yr. Avg Tenth Street 299 Annual 1, Yr. Avg. 1, , Tenth Street 300 Annual 1, Yr. Avg. 1, , Tenth Street 301 Annual , Yr. Avg , Tenth Street Annual 4, , Substation 5 Yr. Avg. 4, , Electric System Reliability Report

69 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Thrashers Corner 275 Annual Yr. Avg Thrashers Corner 276 Annual 1, , Yr. Avg. 1, , Thrashers Corner 277 Annual 1, Yr. Avg. 1, Thrashers Corner 278 Annual 2, Yr. Avg. 2, , Thrashers Corner 3304 Annual Yr. Avg Thrashers Corner 3471 Annual Yr. Avg Thrashers Corner 3472 Annual 1, Yr. Avg. 1, , Thrashers Corner 3473 Annual Yr. Avg Thrashers Corner 3474 Annual Yr. Avg Thrashers Corner Annual 7, , Substation 5 Yr. Avg. 6, , Three Lakes 1818 Annual , Yr. Avg , Three Lakes 1819 Annual 1, , Yr. Avg. 1, , Three Lakes 1820 Annual 1, , Yr. Avg. 1, , Three Lakes 1821 Annual , Yr. Avg , Three Lakes Annual 4, ,424, Substation 5 Yr. Avg. 4, ,197, Electric System Reliability Report 69

70 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Tulalip 505 Annual , Yr. Avg , Tulalip 506 Annual Yr. Avg , Tulalip 507 Annual 1, , Yr. Avg. 1, , Tulalip 508 Annual , Yr. Avg , Tulalip Annual 2, , Substation 5 Yr. Avg. 2, , Turners Corner 1428 Annual Yr. Avg , Turners Corner 1429 Annual 1, , Yr. Avg. 1, , Turners Corner 1430 Annual , Yr. Avg , Turners Corner 1431 Annual , Yr. Avg , Turners Corner 4310 Annual Yr. Avg , Turners Corner Annual 3, , Substation 5 Yr. Avg. 2, , Electric System Reliability Report

71 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Twentieth 1493 Annual Avenue 5 Yr. Avg Twentieth 1494 Annual Avenue 5 Yr. Avg Twentieth 1495 Annual , Avenue 5 Yr. Avg Twentieth 1496 Annual Avenue 5 Yr. Avg , Twentieth 2723 Annual , Avenue 5 Yr. Avg , Twentieth 2724 Annual Avenue 5 Yr. Avg Twentieth 2725 Annual Avenue 5 Yr. Avg , Twentieth 2726 Annual , Avenue 5 Yr. Avg , Twentieth Avenue Annual 2, , Substation 5 Yr. Avg. 2, , Village 4304 Annual , Yr. Avg , Village 4305 Annual 1, , Yr. Avg. 1, , Village 4306 Annual Yr. Avg Village 4307 Annual , Yr. Avg Village Annual 2, , Substation 5 Yr. Avg. 1, , Electric System Reliability Report 71

72 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Wallace River 4485 Annual , Yr. Avg , Wallace River 4486 Annual Yr. Avg Wallace River 4487 Annual Yr. Avg , Wallace River Annual , Substation 5 Yr. Avg , Waterfront 1842 Annual 1, Yr. Avg. 1, , Waterfront 1843 Annual Yr. Avg , Waterfront 1846 Annual , Yr. Avg , Waterfront 1847 Annual , Yr. Avg , Waterfront Annual 3, , Substation 5 Yr. Avg. 3, , Electric System Reliability Report

73 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI West Monroe 631 Annual Yr. Avg , West Monroe 632 Annual 1, Yr. Avg. 1, , West Monroe 633 Annual , Yr. Avg , West Monroe 634 Annual , Yr. Avg , West Monroe 3360 Annual , Yr. Avg , West Monroe 3361 Annual 1, Yr. Avg. 1, , West Monroe 3362 Annual 1, Yr. Avg. 1, West Monroe 3363 Annual , Yr. Avg , West Monroe Annual 7, , Substation 5 Yr. Avg. 6, , Westgate 404 Annual Yr. Avg , Westgate 405 Annual 1, , Yr. Avg. 1, , Westgate 406 Annual 1, Yr. Avg. 1, , Westgate 407 Annual , Yr. Avg. 1, , Westgate Annual 4, , Substation 5 Yr. Avg. 4, , Electric System Reliability Report 73

74 Circuit # of Number of Customer Substation Number Customers Outages Minutes SAIDI CAIDI SAIFI Woods Creek 1808 Annual 1, , Yr. Avg. 1, , Woods Creek 1809 Annual 1, , Yr. Avg. 1, , Woods Creek 1810 Annual , Yr. Avg , Woods Creek 1811 Annual 1, , Yr. Avg. 1, , Woods Creek Annual 5, , Substation 5 Yr. Avg. 5, ,574, Electric System Reliability Report

75 Figure A1: Snohomish County Public Utility District System Average Interruption Duration Index (SAIDI) by Circuit Entire Year -- Transmission and Distribution Outages, Storm Outages Not Included 2015 Electric System Reliability Report 75

76 Figure A2: Snohomish County Public Utility District System Average Interruption Frequency Index (SAIFI) by Circuit Entire Year -- Transmission and Distribution Outages, Storm Outages Not Included Electric System Reliability Report