Application instruction for the maintenance of frequency controlled reserves

Transcription

1 Appendix 2 to the Yearly Agreement and Hourly Market Agreement for Frequency Controlled Normal Operation Reserve and Frequency Controlled Disturbance Reserve Valid as of 1 January 2017 Unofficial translation Application instruction for the maintenance of frequency controlled reserves

2 1 January 2017 Appendix 2 2 (15) Contents 1 GENERAL PROCUREMENT OF RESERVES REQUIREMENTS IMPOSED ON RESERVE CAPACITY Frequency controlled normal operation reserve Relay-connected frequency controlled normal operation reserve Frequency controlled disturbance reserve Relay-connected frequency controlled disturbance reserve REPORTING AND FOLLOW-UP OF RESERVE MAINTENANCE Reserve plans Real-time data History data Invoicing data Other information Fingrid s reporting to Reserve Holder CALCULATION PRINCIPLES OF RESERVE CAPACITY... Virhe. Kirjanmerkkiä ei ole määritetty. 6 CALCULATION PRINCIPLES OF ENERGY FEE VERIFICATION OF TECHNICAL REGULATION FEATURES OF RESERVE CAPACITY Execution of regulation tests Documentation of regulation tests Accuracy requirements concerning measuring and registration equipment Quantities specified on the basis of regulation tests Frequency controlled normal operation reserve Frequency controlled disturbance reserve Dead band in frequency regulation Accuracy of frequency measurement Frequency response Measurement principle of power plant machineries Measurement of frequency controlled normal operation reserve Measurement of frequency controlled disturbance reserve Measurement of dead band and dead time in frequency regulation Other issues to be considered in the measurements Measurement principle of loads... 15

3 1 January 2017 Appendix 2 3 (15) 1 GENERAL This Application Instruction presents the principles and general procedures related to the maintenance and procurement of frequency controlled reserves. This Application Instruction is an appendix to the Yearly Agreement and Hourly Market Agreement for Frequency Controlled Normal Operation Reserve and Frequency Controlled Disturbance Reserve, signed between Fingrid Oyj (Fingrid) and Reserve Holder. The maintenance obligations concerning the frequency controlled reserves have been agreed through an operation agreement signed between the Nordic transmission system operators. The objective in the procurement of frequency controlled reserves is a structure that ensures the sufficiency of the reserves at all times, and at the same time enables efficient competition within procurement conditions which are equal to all. In order to fulfil the reserve obligation, there can also be transactions between countries. Fingrid has a right to sell reserves, which have been sold to Fingrid by reserve holders, further to other transmission system operators. The Nordic transmission system operators divide the obligation concerning the frequency controlled normal operation reserve between the subsystems annually in proportion to the annual energies used by them respectively. The obligation for Finland is approx. 140 MW. The obligation concerning the frequency controlled disturbance reserve is divided between the subsystems weekly in proportion to the dimensioning faults. The obligation for Finland is approx. 260 MW. 2 PROCUREMENT OF RESERVES Fingrid procures some of the relevant obligation from the yearly market from power plants and loads located in Finland, on the basis of competitive bidding. There is a separate market for the frequency controlled normal operation reserve and frequency controlled disturbance reserve. In addition, Fingrid procures reserves from the direct current transmission links from Russia and Estonia as well as through daily purchases from the hourly market in Finland and the other Nordic countries. Participation in the hourly market can also take place in the middle of the calendar year, and it does not require participation in the yearly market. Competitive bidding for the yearly market is arranged in September-October for the next calendar year. It is not possible to start participating in the maintenance of reserves in the yearly market in the middle of the yearly agreement period. In the yearly market and hourly market for the frequency controlled disturbance reserve, Reserve Holder can combine reserves from several different balances and participate in the maintenance of the frequency controlled disturbance reserves also using reserves included in the balances of different balance providers. Reserve Holder does not have to be the owner or balance provider of the reserve. Reserve Holder shall have the consent of the owner of the reserve for the reserve operation conforming to the Yearly Agreement and Hourly Market Agreement for Frequency Controlled Normal Operation Reserve and Frequency Controlled

4 1 January 2017 Appendix 2 4 (15) Disturbance Reserve. At Fingrid s separate request, Reserve Holder shall deliver the consent of the owner of the reserve to Fingrid. An individual reserve can only be offered by one reserve holder to each reserve market. The volume of reserve produced by a single unit for each hour shall not exceed 70 MW. Moreover, Fingrid restricts the total volume of relay-connected load contributing to the maintenance of the frequency controlled disturbance reserve and activating in accordance with Table 1 to a maximum of 100 MW in each hour. In an island situation of the power system, when Finland is disconnected from the rest of the Nordic power system, and in situations where the domestic supply and procurement from other countries together are not sufficient to cover Fingrid s reserve obligations in all hours, Reserve Holder shall, at Fingrid s request, keep the frequency regulation of all reserves, which are running, in operation. For capacity maintained on the basis of such request, Fingrid shall pay Reserve Holder compensation in accordance with item 7 of the Yearly Agreement for Frequency Controlled Normal Operation Reserve and Frequency Controlled Disturbance Reserve. If, in addition to this, Fingrid requests Reserve Holder to maintain more reserves, and, as a result of this, Reserve Holder has to change the target power of the reserves, a transaction corresponding to the change of the target power shall be agreed at the price of regulating power. 3 REQUIREMENTS IMPOSED ON RESERVE CAPACITY 3.1 Frequency controlled normal operation reserve The reserve unit used in the maintenance of the frequency controlled normal operation reserve shall regulate almost linearly within a frequency range of Hz so that the dead band in frequency regulation is at the most 50 ±0.05 Hz. As a result of a frequency change of 0.10 Hz, the regulation shall be activated in full in three minutes Relay-connected frequency controlled normal operation reserve A reserve that consists of relay-connected resources shall regulate in parts linearly within a frequency range of Hz so that activation takes place inside the blue area indicated in Figure 1 (reserve capacity on the y-axis). The maximum dead band in frequency regulation may be 50 ± 0.05 Hz. The red line in the figure represents one possible regulation curve that meets the requirements.

5 1 January 2017 Appendix 2 5 (15) Figure 1. Activation of reserve that contributes to the frequency controlled normal operation reserve and consists of relay-connected resources. 3.2 Frequency controlled disturbance reserve The reserve unit used in the maintenance of the frequency controlled disturbance reserve shall regulate almost linearly so that the activation begins when the frequency decreases below Hz, and the full reserve shall be activated at a frequency of Hz. Half of the frequency controlled disturbance reserve shall be activated in five seconds, and it shall be activated in full in 30 seconds at a stepped frequency change of Hz Relay-connected frequency controlled disturbance reserve A reserve that consists of relay-connected resources shall regulate in parts linearly within a frequency range of Hz so that activation takes place inside the blue area indicated in Figure 2 (reserve capacity on the y-axis). The red line in the figure represents one possible regulation curve that meets the requirements.

6 1 January 2017 Appendix 2 6 (15) Figure 2. Activation of reserve that contributes to the frequency controlled disturbance reserve and consists of relay-connected resources. Alternatively, the entire relay-connected reserve can be disconnected at the same time. In this case, the relay-connected load used in the maintenance of the frequency controlled disturbance reserve shall disconnect in accordance with one or more disconnection steps shown in Table 1. Fingrid restricts the total volume of a relay-connected load that disconnects at the same time and contributes to the maintenance of the frequency controlled disturbance reserve to a maximum of 100 MW in each hour. Table 1. Permitted settings to be followed in the disconnection of relay-connected load. Frequency (Hz) Disconnection time (s) As an example, alternative Hz and 5 s means that the reserve shall be fully activated in a maximum of five seconds if the frequency of the power system is Hz or less. Reserve Holder may connect the load back to the grid when the frequency has been at least Hz for three minutes.

7 0} 1 January 2017 Appendix 2 7 (15) 4 REPORTING AND FOLLOW-UP OF RESERVE MAINTENANCE Reserve Holder and Fingrid shall supply each other with information electronically. Reserve Holder shall provide its own balance provider with information related to the maintenance of the frequency controlled reserves, balance management and balance settlement. Reserve Holder shall agree on this separately with its balance provider. 4.1 Reserve plans Reserve Holder, which has signed a yearly agreement, shall supply Fingrid with the hourly reserve plan concerning the reserve volumes in the hours of the next calendar day in the CET time zone (Elspot day). The reserve plan shall be balance-specific (production or consumption). The volume stated in the reserve plan can be at the most equal to the reserve volume agreed in the yearly agreement. The reserve plan shall be submitted at an accuracy of 0.1 MW. The plans shall be delivered to Fingrid in EDI messaging using the DELFOR message format, by The reserve plan shall reach Fingrid by the deadline. Plans arriving after the deadline are not accepted. No reserve plan is delivered of transactions conducted in the hourly market. 4.2 Real-time data Reserve Holder shall deliver, at its own expense, the following unit-specific data to a point of delivery indicated by Fingrid: volume of the frequency controlled normal operation reserve (MW) to be maintained volume of the frequency controlled disturbance reserve (MW) to be maintained. The above data shall describe the current actual volume of the reserve maintained. When calculating the data, the current actual regulation capability of the reserve shall be taken into account. As an example, the volume of the frequency controlled normal operation reserve maintained in power plant machinery can be calculated from equation 1. CC FCR N = max[min(pp max PP set value, PP set value PP min, CC reserve volume in tests ), 0] (1) PP max is the current maximum power of power plant machinery PP min is the current minimum power of power plant machinery PP set value is the current set value of power of power plant machinery CC reserve volume in tests is the volume of reserves verified by means of regulation tests Correspondingly, the volume of the frequency controlled disturbance reserve maintained can be calculated from equation 2. CC FCR D, = max min PP max PP set value CC FCR N, CC reserve volume in tests, 0 (2) With regard to loads, the equations 1 and 2 shall, if necessary, be modified so that they are suited to the calculation of the volume of reserves in loads.

8 1 January 2017 Appendix 2 8 (15) If the holder of the reserve has a more precise calculation method, it can also be used. The calculation method shall be delivered to Fingrid. Fingrid can accept that the measurement data on small reserves is delivered as sum information. The maximum sending cycle of the data shall be three minutes. The data shall be delivered in accordance with separate guidelines provided by Fingrid. Fingrid monitors the maintenance and activation of the reserves on the basis of the real-time data. 4.3 History data At Fingrid s request, Reserve Holder shall deliver the unit-specific active power data on the reserves contributing to the regulation in a numerical format at an accuracy of one second so that the activation of the reserve capacity in accordance with the Agreement can be verified for example in disturbance situations. The active power data shall either be time-stamped so that the data is synchronised to the Finnish time, or alternatively the history data shall contain frequency measurement data, which is synchronised to the active power measurement data. Reserve Holder shall store the history data for at least four days. 4.4 Invoicing data Reserve Holder shall deliver the following actual data on reserves contributing to the maintenance of the reserves. This data shall be delivered at Reserve Holder s own expense as hourly time series. unit-specific hourly average power unit-specific hourly maximum power volume of frequency controlled normal operation reserve by virtue of the yearly agreement and in the hourly market volume of frequency controlled disturbance reserve by virtue of the yearly agreement and in the hourly market. The data shall be delivered to Fingrid in electronic EDI messages using the MSCONS message format within 10 days from the supply date. 4.5 Other information At Fingrid s request, Reserve Holder shall deliver descriptions of the technical characteristics of the reserves. These descriptions shall cover the general information on the generator and turbine, including the constants of inertia and descriptions of the waterways of the power plants, including the water time constant. Moreover, Reserve Holder shall deliver a description of the functioning of frequency regulation and of the frequency measurement used. This refers to a description of the functioning of the turbine controller and of any other issues that influence the functioning of frequency regulation, such as the application of various filters and dead bands in the frequency measurement. In so far as the delivery of the data would entail excessive costs for Reserve Holder, the parties shall negotiate on what type of data is considered sufficient for delivery.

9 1 January 2017 Appendix 2 9 (15) 4.6 Fingrid s reporting to Reserve Holder Fingrid shall report the following hourly data to Reserve Holder: actual transactions and prices in the hourly market volume and price of reserve electricity. 5 CALCULATION PRINCIPLES OF RESERVE CAPACITY The volume of the frequency controlled normal operation reserve and disturbance reserve to be maintained is calculated in accordance with the following principles: 1. When the average power of the reserve unit is close to the minimum power P min, the volume of the frequency controlled normal operation reserve P FCR-N is calculated in so far as there is regulating reserve power available for the hour in question within the scope of minimum power; however, at the most the volume verified in regulation tests. 2. When the average power of the reserve unit is higher than the frequency controlled normal operation reserve verified in the regulation tests but below the maximum power P max so that the difference between the maximum power and the average power is higher than or equal to the sum of the frequency controlled normal operation reserve and disturbance reserve P FCR-D, the proportion of the above reserves is calculated at the full volume. 3. When the average power of the reserve unit is close to the maximum power, first the volume of the frequency controlled normal operation reserve and after it the volume of the frequency controlled disturbance reserve is calculated in so far as there is regulating reserve power left after the frequency controlled normal operation reserve has been deducted from the maximum power; however, at the most the volume of the frequency controlled disturbance reserve verified in the regulation tests. 4. When the average power of the reserve unit is almost at the maximum power, the volume of the frequency controlled normal operation reserve is calculated in so far as there is regulating reserve power available for the hour in question within the maximum power; however, at the most the volume of the frequency controlled normal operation reserve verified in the regulation tests. Figure 3. Calculation of frequency controlled normal operation reserve and disturbance reserve at different power ranges.

10 1 January 2017 Appendix 2 10 (15) 6 CALCULATION PRINCIPLES OF ENERGY FEE Reserve electricity refers to the balance error caused by the frequency controlled normal operation reserve in the production balance or in the consumption balance, with the reserve electricity calculated in accordance with equation 3. Reserve electricity = ΣR t 50Hz k 3600s (3) R denotes the actual total volume of the frequency controlled normal operation reserve of all parties included in balance provider s balance multiplied by 10 (frequency response). A party s frequency controlled normal operation reserve is verified by means of measurements, and it is at the most equal to the total volume agreed in the yearly agreement and in the hourly market. Δt denotes the change in the time deviation in seconds during the hour in question. The correction coefficient (k=0.7) takes into account the effect of the dead band on the activated energy. The balance error caused by the frequency controlled normal operation reserve is calculated hourly and removed by means of a transaction from the balance of Reserve Holder s balance provider in conjunction with the nation-wide balance settlement. A balance error caused by production is taken into account in the production balance, and, correspondingly, a balance error caused by a load is taken into account in the consumption balance. The basis of compensation is the hourly regulating price as follows: In a situation with a frequency below the normal range, the calculatory energy caused by the frequency controlled normal operation reserve is reimbursed at the up-regulating price. In a situation with a frequency above the normal range, the calculatory energy caused by the frequency controlled normal operation reserve is charged at the down-regulating price. 7 VERIFICATION OF TECHNICAL REGULATION FEATURES OF RESERVE CAPACITY Reserve Holder shall make sure that Reserve Holder s unit participating in the maintenance of the frequency controlled normal operation reserve and disturbance reserve fulfils the requirements imposed on its regulation features within the available capacity. The fulfilment of the requirements shall be verified by means of regulation tests carried out using regulation settings which conform to a normal run in a normal operating situation of the reserve unit. A number of regulation settings (for example at different statics) can be specified for a reserve unit, and the functioning of all of these regulation settings shall be verified by means of regulation tests. The regulation tests shall be conducted before the entry into force of the Agreement. Reserve Holder shall make sure that the regulation tests are performed on the reserve unit whenever the technology relating to the system is modified in a manner which has an impact on its use as reserve. Such modifications include power increases of the power plant machinery or changes influencing its efficiency, renewal of control devices of the reserve unit, and changes to control parameters.

11 1 January 2017 Appendix 2 11 (15) The regulation settings shall be verified by Reserve Holder after service and repairs and, if necessary, regulation tests shall be carried out if there is reason to assume that the regulation capability of the reserve unit has altered. If no modifications influencing regulation capability are performed on the reserve unit, the regulation tests shall be repeated at least every ten years. The parties shall agree jointly on the introduction of new reserve values specified by means of regulation tests. 7.1 Execution of regulation tests Reserve Holder is responsible for carrying out the regulation tests in accordance with this Application Instruction. Fingrid has the right to send its representative to the regulation test. Reserve Holder is responsible for the costs of the tests and Fingrid only for its own personnel costs. Fingrid shall be informed of the regulation tests at least two weeks before the measurement date so that Fingrid can send its own specialist to the test. In this conjunction, Reserve Holder shall inform Fingrid of the measurement date and location and present the measurement programme. If this is not done, Fingrid has the right not to accept the measurement results Documentation of regulation tests Reserve Holder shall be responsible for drawing up the measurement records and for delivering them to Fingrid after the regulation tests. If Reserve Holder does not present reliable test results, Fingrid does not have to accept the unit in question for reserve maintenance. Moreover, Reserve Holder shall describe the operating principle of the regulation system Accuracy requirements concerning measuring and registration equipment Various sources cause inaccuracy in the measurement results. These include the inaccuracy of frequency setting, instrument transformers, power sensor, and A/D card. The total error in the measurement shall be below 10 per cent. The sampling interval of the registration equipment shall be at the most 0.2 seconds so that the frequency controlled normal operation reserve and disturbance reserve as well as other parameters relating to the regulation features can be defined at sufficient accuracy. 7.2 Quantities specified on the basis of regulation tests The regulation tests are used for specifying the maximum volume of the frequency controlled normal operation reserve and frequency controlled disturbance reserve that the reserve unit can provide for the reserve market. The reserve values are determined at an accuracy of 0.1 MW Frequency controlled normal operation reserve The frequency controlled normal operation reserve is that change in active power which is activated automatically within three minutes when there is a stepped frequency change of ±0.10 Hz. The frequency controlled normal operation reserve

12 1 January 2017 Appendix 2 12 (15) must remain activated even after three minutes if the frequency continues to differ from the nominal frequency of 50 Hz Frequency controlled disturbance reserve The frequency controlled disturbance reserve is the smaller of the following active powers: that which is activated at a stepped frequency deviation of Hz in 30 seconds or that which is activated in five seconds multiplied by two. With relay-connected loads that follow the activation method of Table 1, the frequency controlled disturbance reserve is that change in active power which is activated within the required time at the selected disconnection step in accordance with Table Dead band in frequency regulation The dead band of frequency regulation is the smallest frequency change to which the reserve unit responds so that the activated active power can be measured Accuracy of frequency measurement The accuracy of the frequency measurement of the reserve unit shall be at least 10 mhz Frequency response The capability of the reserve unit to participate in automatic frequency regulation is referred to as frequency response R. Its magnitude is determined by the features of the reserve unit and by the settings of the controllers related to it. The frequency response can be calculated by means of the frequency change and the consequently obtained power change using equation 4. ΔP R = (4) Δ f 7.3 Measurement principle of power plant machineries The regulation test measurements shall be carried out by means of step response tests. The step response test shall be carried out by supplying a permanent frequency deviation to the frequency measuring branch of the turbine controller. The measurement of the frequency of the grid shall be interrupted for the duration of the test, and instead of it, a signal corresponding to the step change shall be supplied to the frequency measuring branch. f set f change f cur Turbine controller Turbine Generator Grid Figure 4. Supplying the step change to the frequency measuring branch.

13 1 January 2017 Appendix 2 13 (15) If the test cannot be performed by supplying the frequency deviation to the frequency measuring branch, the step response test can be carried out by simulating the change in the frequency of the grid or by changing the set value of frequency. In a test carried out by changing the set value of frequency, the frequency changes have the opposite effect as compared to frequency changes which are supplied to the frequency measuring branch. In other words, a change of Hz in the set value corresponds to a change of Hz in the frequency of the grid. If the test is carried out by changing the set value, both the set value and the measurement value of the frequency of the grid shall be the same as accurately as possible in the initial situation. The power change achieved as a result of the step change shall be measured and the results shall be registered. Before the beginning of the test, the settings of the turbine controller shall be recorded, and a parameter list concerning the regulation features of the power plant machinery shall be drawn up. Other factors potentially influencing the results of the test, such as falling height of hydropower and external temperature, shall also be recorded. If, due to the features or structure of the power plant machinery or control equipment, the test or a part of it cannot be performed as described above, Fingrid and Reserve Holder can agree on another procedure to verify the regulation capability of the power plant machinery. Reserve Holder shall submit an alternative procedure to Fingrid for evaluation one week before the measurement. Reserve Holder shall be responsible for the potential additional costs required by an alternative measurement procedure Measurement of frequency controlled normal operation reserve The frequency controlled normal operation reserve and frequency response shall be verified by using a step response test on the regulating power plant machineries. In the test, deviations Hz and Hz shall be supplied to the measuring branch for frequency regulation. The power change caused by the frequency change shall be recorded for five minutes. The measurement result shall be recorded at three minutes. If the frequency deviation cannot be supplied to the measuring branch, the step response test shall be carried out by changing the guideline value for frequency with deviations Hz and Hz Measurement of frequency controlled disturbance reserve The frequency controlled disturbance reserve shall be verified by means of a step response test, by supplying, instead of the grid frequency, a signal which corresponds to a frequency deviation of Hz to the turbine controller. The power change caused by the frequency change shall be registered for two minutes. The measurement result shall be recorded at 5 and 30 seconds. The disturbance reserve shall remain activated even after 30 seconds. If the test is carried out by changing the guideline value for frequency, a guideline value deviation of Hz shall be supplied in the measurement of the frequency controlled disturbance reserve.

14 1 January 2017 Appendix 2 14 (15) The power regulation of some power plant machineries shifts over to disturbance operation parameters automatically when the frequency decreases below Hz. In this case, the turbine controller parameters shift automatically from normal operation values to disturbance operation values. For this reason, the measurement of the frequency controlled disturbance reserve at such power plants shall be carried out using the parameters for disturbance operation Measurement of dead band and dead time in frequency regulation The dead band of frequency regulation shall be measured in all power plant machineries participating in reserve maintenance. If the power plant machinery is such that the dead band for its turbine controller can be set as a parameter, the functioning of regulation shall be tested outside the set dead band so that the turbine controller is supplied a step change which is slightly greater than the dead band, and the consequently activated active power shall be measured for three minutes from the step change. If the power plant machinery is such that the dead band for frequency regulation cannot be set, the measurement shall be carried out by supplying a stepped frequency change to the turbine controller, and the consequently activated active power shall be measured. The activated active power shall be measured for three minutes from the step change. The first frequency change to be used is ±10 mhz, after which the measurement shall be carried out, if necessary, at four other points at steps of ±10 mhz up to a frequency deviation of ±50 mhz. The measurement shall be carried out using the same power levels as in the measurements of the frequency controlled normal operation reserve and disturbance reserve in accordance with Figure 4. The dead band of the power plant machinery is the lowest frequency change to which the machinery responds so that the activated active power can be measured. The measurement shall be carried out both with and without clearance. If different values are obtained for the dead band with different power levels, the average of the dead bands measured shall be applied to the Agreement. If the power plant consists of at least two power plant machineries which are similar in terms of their power, structure and the features of the turbine controller, the dead band can be measured in one of these machineries if so agreed upon between Fingrid and Reserve Holder separately, and the result obtained shall be applied to all power plant machineries at the same magnitude Other issues to be considered in the measurements The active power values before and after the frequency change shall be recorded. The tests shall be performed at the following power levels: at the smallest power P min,ajo, at which there is a willingness to be able to offer the reserve at the greatest power P max,ajo, at which there is a willingness to be able to offer the reserve at power PP 50 %,aaaaaa = PP max,ajo PP min,ajo P max,ajo 2 existing between the powers P min,ajo and

15 1 January 2017 Appendix 2 15 (15) The frequency controlled normal operation reserve and disturbance reserve is the smallest of the measurement results obtained at the above-mentioned power levels. It shall be remembered in the measurement of the frequency controlled disturbance reserve that the frequency controlled normal operation reserve shall also be activated within three minutes from the stepped frequency change. The measurement results shall be registered, and curves shall be drawn of each measurement, indicating the power change after the frequency change. Based on the measurement of the frequency controlled normal operation reserve, frequency response shall be calculated at each power level using Equation Measurement principle of loads Regulation test measurements shall be performed on loads by means of step response tests and using principles to be agreed individually in each case. With relay-connected loads serving as frequency controlled disturbance reserves, the functioning of the reconnection of loads shall also be indicated in the regulation tests.