Hydroelectric generating set primary frequency modulation performance online evaluation method

Abstract

A hydroelectric generating set primary frequency modulation performance online evaluation method establishes a plurality of primary frequency modulation performance evaluation indexes, introduces an entropy weight method and an empowerment method, constructs a primary frequency modulation performance comprehensive evaluation system, and acquires and analyzes historical data and real-time data of a hydroelectric generating set. Real-time supervision and comprehensive evaluation of the primary frequency modulation performance of the hydroelectric generating set are realized, the problems of few evaluation angles, strong subjectivity, single data source and the like are effectively solved, weak links of the primary frequency modulation of the hydroelectric generating set can be found in time, the primary frequency modulation performance of the set is adjusted and optimized, the primary frequency modulation capability of the set is improved from management, and the efficiency is improved. A primary frequency modulation control system and system of a hydroelectric generating set are guided and helped to be perfected, so that random fluctuation of a power grid is quickly eliminated, the electric energy quality is improved, and safe, stable and economical operation of the set is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic machine mechanical testing and relates to an online evaluation method for primary frequency regulation performance of a hydroelectric unit. Background Art

[0002] Primary frequency regulation refers to the automatic response of the generator set to adjust the active output through the speed regulation system to maintain the stability of the power system frequency when the power system frequency deviates from the target frequency. The primary frequency regulation function is an important means to maintain the stability of the power grid.

[0003] The proportion of new energy sources continues to increase, and the rapid consumption of power systems requires flexible adjustment of resources. Its intermittent, random, and volatile characteristics make system adjustment more difficult, increase the difficulty of controlling system operation, and make system balance and safety issues more prominent. With the construction of new power systems, more power electronic equipment will be connected to the power grid, and the form of the power grid will undergo profound changes. The evolution of the power system will gradually break through the existing theoretical and operational control framework, and the risk of safe and stable operation of the power grid will gradually increase. On the one hand, the impact of abnormal operation of large-capacity units on the safe and stable operation of the power grid is more significant; on the other hand, the mutual influence and interaction between regional power grids are further enhanced, and the large-scale application of new technologies and new equipment makes the operation characteristics of the power grid more complex. Hydropower stations play an important role in the power system. The primary frequency regulation of hydropower units can quickly provide power support when the power grid suddenly changes in large loads, thereby improving the reliability and stability of the power system; the regulation of short-term load fluctuations can reduce the action of secondary frequency regulation, optimize system dispatching, and stabilize the frequency of the power grid. The primary frequency regulation performance of hydropower units directly affects the operational stability, safety, and economy of the power system. Therefore, it is crucial to carry out the evaluation of the primary frequency regulation control performance of hydropower units. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an online evaluation method for the primary frequency regulation performance of a hydropower unit, which evaluates the response speed index, adjustment amplitude index, adjustment deviation index and response index index of the primary frequency regulation effect, and the comprehensive evaluation is more systematic and accurate.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: an online evaluation method for primary frequency regulation performance of a hydropower unit, comprising the following steps: S1, establish evaluation indicators, including primary frequency modulation response speed indicator, primary frequency modulation adjustment amplitude indicator, primary frequency modulation adjustment deviation indicator and primary frequency modulation response index indicator; S2, determine the indicator weights, combine the entropy weight method with the empowerment method, reflect objective data information, and respect subjective initiative; S3, collects operation data, and collects data required for online evaluation of the primary frequency regulation performance of the unit; S4, define effective disturbance, define effective disturbance of primary frequency modulation, determine a method for selecting a frequency band, and use this frequency band to examine whether the primary frequency modulation response characteristics of the unit are qualified; S5, structural evaluation, the response speed index is used to examine the rapidity of the primary frequency regulation; the adjustment amplitude index is used to examine the effectiveness of the unit's primary frequency regulation at the initial stage; the adjustment deviation index is used to examine the unbiasedness of the unit's primary frequency regulation throughout the entire process; the response index index is used to examine the overall effect of the unit's primary frequency regulation process, which is an important supplement to the response speed index, adjustment amplitude index, and adjustment deviation index; S6, publish the evaluation results, judge whether the four performance indicators of primary frequency modulation are qualified according to the calculation results, and give an evaluation.

[0006] In S1, it is stipulated that the unit primary frequency regulation load response lag time T0 should be less than T1. The T1 value is determined according to the grid demand and the unit is s. The primary frequency modulation response speed index α1 is: ; (1) If α1>1, the primary frequency modulation response speed index is qualified; otherwise, the primary frequency modulation response speed index is unqualified.

[0007] In S1, under ideal conditions, when the grid frequency crosses the dead zone, it is necessary to make precise adjustments according to the change of the unit active output with the frequency, so that the theoretical adjustment amount ΔP(t) is consistent with the actual adjustment amount, that is, (2) Where: σ is the unit adjustment coefficient; is the deviation of frequency relative to the dead zone; P N is the rated capacity of the unit; P (t) is the actual output of the unit at time t; P 0 is the actual output of the unit when the frequency crosses the dead zone. To prevent measurement errors, the average value of the k moments before the frequency crosses the dead zone can be used instead, k∈R, in seconds; The primary frequency regulation adjustment range index is used to measure the unit output adjustment range at the initial stage of primary frequency regulation; it stipulates that the load adjustment range of the unit within T2 should reach the theoretical adjustment load y1 corresponding to the frequency extreme point within this period, and the unit of T2 is s. The values ​​of T2 and y1 can be set according to the specific conditions of the power grid; The primary frequency modulation adjustment amplitude index α2 is: ; (3) Where: P max and ΔP maxThey are respectively the maximum actual output of the units in T2 and the maximum theoretical adjustment amount; if α2≥1, the primary frequency regulation adjustment amplitude index is qualified.

[0008] In S1, the primary frequency regulation deviation index is used to measure the unbiasedness of the primary frequency regulation of the unit; it is stipulated that from the time when the grid frequency changes beyond the primary frequency regulation dead zone of the unit to 60s or until the frequency changes back to the primary frequency regulation dead zone, the average value of the deviation between the actual output of the unit and the theoretical target should be within y2 of the maximum value of the theoretical adjustment load, and the y2 value is set according to the specific situation of the grid; The primary frequency modulation adjustment deviation index α3 is: (4) Where: P(t i ), ΔP(t i ), ΔPt i max are the time periods from when the frequency crosses the frequency modulation dead zone to 60s or when the frequency returns to the dead zone. i The actual output of the unit at the moment, the theoretical adjustment amount and the maximum value of the theoretical adjustment amount; n is the number of sampling points; if α3>1, the primary frequency adjustment deviation index is qualified.

[0009] In S1, the primary frequency regulation response index measures the overall effect of the unit's primary frequency regulation by the size of the integrated power. It is stipulated that when the grid frequency changes beyond the primary frequency regulation dead zone of the unit for 3 to 60 seconds or when the frequency changes back to the primary frequency regulation dead zone, the actual weighted integrated power of the unit's primary frequency regulation must reach y3 or more of the expected integrated power, and the y3 value is set according to the specific situation of the grid. Primary frequency modulation response index A u for: ; (5) If A u >1, the primary frequency regulation response index is qualified; where: Ψ(t) is a weighting function, which weights the time period of concern in the primary frequency regulation process to highlight the primary frequency regulation effect of the unit in this period; W(t) is an adjustment function, which is used to fit the deviation between the actual output change of the unit and the theoretical adjustment amount in the initial stage, and the first-order inertia link is used for fitting; Weighting function Ψ (t) and the adjustment function W (t) are: ; (6) ;(7).

[0010] In S2, determine the weight of each evaluation index: For the jth indicator, its entropy value is e j for: (8) Where k = 1 / ln(m), ; Calculate the entropy weight coefficient p of the jth indicator j for: ; (9) In the formula, β j =1-e j , is the coefficient of difference of index j; Calculate the comprehensive weight ω of the jth indicator j for: (10) Where 0≤λ j ≤1, subjective and objective compromise coefficient; q j is the jth evaluation determined subjectively by the expert The importance of the indicator; For n evaluation indicators, the weight coefficients determined by experts are ranked from small to large in order of importance. The following formula is used to determine: ; (11) In the formula, q k (k=1,2,…n) satisfies .

[0011] In S3, the data required for online evaluation of the primary frequency regulation performance of the unit are collected, including the unit's primary frequency regulation load response lag time T0, the unit's actual output P(t) at time t, and the unit's actual output P0 when the frequency crosses the dead zone; a database is built to save the unit's historical data, and the historical data can be called to evaluate the unit's primary frequency regulation performance.

[0012] In S4, the definition of effective disturbance includes: the time when the frequency crosses the dead zone: the frequency is required to be outside the dead zone value of the first frequency modulation for at least τ1, where τ1 is in seconds; the amplitude reached by the frequency in the initial stage: the frequency is required to be within τ2 from the beginning of exceeding the dead zone of the first frequency modulation, the maximum value should be greater than (50.0+x) Hz, or the minimum value should be less than (50.0-x) Hz, and it should last for more than c, where c is in seconds, and τ2, x, and c are given according to the actual situation of the system.

[0013] In S6, if all four performance indicators of primary frequency modulation are qualified, the comprehensive evaluation result R i Determined by the following formula: (12) Among them, i=1,2,…,m,j=1,2,…n are the number of evaluation objects and evaluation indicators respectively; The evaluation results of various evaluation indicators of primary frequency regulation of hydropower units and the comprehensive evaluation results are published, and the evaluation results are saved in the database for comparative analysis with historical evaluation results.

[0014] The main beneficial effects of the present invention are: From the perspective of stable operation of the power grid and rapid frequency regulation, the initial period of a frequency regulation process should pursue rapidity and effectiveness, and quickly adjust the frequency to a limited range; in the later period, it should pursue unbiasedness to ensure smooth frequency changes.

[0015] In order to evaluate the primary frequency regulation performance of the hydropower unit as comprehensively and accurately as possible, the feasibility of monitoring and implementing various indicators of the hydropower unit is also taken into consideration.

[0016] Taking into account the needs of primary frequency regulation in different time periods, response speed index, adjustment amplitude index, adjustment deviation index and response index index are proposed to evaluate the effect of primary frequency regulation, and a hierarchical primary frequency regulation performance evaluation index system for hydropower units is established.

[0017] The entropy weight method is combined with the weighting method to determine the weight of each evaluation index and obtain the weight coefficient of each evaluation index. Finally, the weighted sum of each evaluation index is performed to obtain the comprehensive evaluation result of the primary frequency regulation performance of the hydropower unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0019] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0020] like Figure 1 In the present invention, a method for online evaluation of primary frequency regulation performance of a hydropower unit comprises the following steps: S1, establish evaluation indicators, including primary frequency modulation response speed indicator, primary frequency modulation adjustment amplitude indicator, primary frequency modulation adjustment deviation indicator and primary frequency modulation response index indicator; S2, determine the indicator weights, combine the entropy weight method with the empowerment method, reflect objective data information, and respect subjective initiative; S3, collects operation data, and collects data required for online evaluation of the primary frequency regulation performance of the unit; S4, define effective disturbance, define effective disturbance of primary frequency modulation, determine a method for selecting a frequency band, and use this frequency band to examine whether the primary frequency modulation response characteristics of the unit are qualified; S5, structural evaluation, the response speed index is used to examine the rapidity of the primary frequency regulation; the adjustment amplitude index is used to examine the effectiveness of the unit's primary frequency regulation at the initial stage; the adjustment deviation index is used to examine the unbiasedness of the unit's primary frequency regulation throughout the entire process; the response index index is used to examine the overall effect of the unit's primary frequency regulation process, which is an important supplement to the response speed index, adjustment amplitude index, and adjustment deviation index; S6, publish the evaluation results, judge whether the four performance indicators of primary frequency modulation are qualified according to the calculation results, and give an evaluation.

[0021] Embodiment 1, Establish evaluation indicators; As an important means of frequency adjustment, primary frequency regulation should be rapid, effective and unbiased. Rapidity means that the unit output is adjusted quickly with the change of frequency to ensure that the grid frequency is adjusted in time. Effectiveness means that after the grid frequency crosses the set dead zone, the unit output changes quickly to a certain amplitude to ensure that the frequency can be significantly adjusted in the direction of the dead zone. Unbiasedness means that the unit output can stably follow the change of frequency within a certain period of time and make corresponding adjustments without over-regulation or under-regulation that will cause a second disturbance to the grid frequency. In the event of a serious frequency accident, the trend of frequency deterioration is slowed down, leaving reaction time for other frequency regulation means such as secondary frequency regulation.

[0022] From the perspective of stable operation of the power grid and rapid frequency adjustment, the initial period of the primary frequency regulation process should pursue rapidity and effectiveness, and quickly adjust the frequency to a limited range; in the later period, it should pursue unbiasedness to ensure stable frequency changes. Based on the needs of primary frequency regulation in different periods, this method proposes response speed indicators, adjustment amplitude indicators, adjustment deviation indicators, and response index indicators to evaluate the effect of primary frequency regulation.

[0023] 1) Primary frequency modulation response speed index (α1) After the grid frequency exceeds the primary frequency regulation dead zone set by the unit, ideally, the unit output should change immediately without delay. However, due to factors such as signal transmission and mechanical dead zone, the unit output change will lag for a certain period of time. This lag time is called the primary frequency regulation load response lag time, and this time is used to measure the response speed of the unit's primary frequency regulation to the change of grid frequency. The smaller the load response lag time of the primary frequency regulation, the faster the response speed.

[0024] It is stipulated that the unit's primary frequency regulation load response lag time T0 should be less than T1 (T1 value is determined according to grid demand, unit is s).

[0025] α1 is: ; (1) If α1>1, the primary frequency modulation response speed index is qualified; otherwise, the primary frequency modulation response speed index is unqualified.

[0026] 2) Primary frequency modulation adjustment range index (α2) Ideally, when the grid frequency exceeds the dead zone, it is necessary to make precise adjustments according to the change of the unit's active output with the frequency, so that the theoretical adjustment ΔP(t) is consistent with the actual adjustment, that is, ; (2) Where: σ is the unit adjustment coefficient; is the deviation of frequency relative to the dead zone; P N is the rated capacity of the unit; P (t) is the actual output of the unit at time t; P 0 is the actual output of the unit when the frequency crosses the dead zone. To prevent measurement errors, the average value of k (k∈R, unit is s) moments before the frequency crosses the dead zone can be taken instead.

[0027] The primary frequency regulation adjustment range index is used to measure the unit output adjustment range at the initial stage of primary frequency regulation. It is stipulated that the load adjustment range of the unit within T2 (in seconds) should reach the theoretical adjustment load y1 corresponding to the frequency extreme point within this period (T2, y1 values ​​can be set according to the specific conditions of the power grid).

[0028] α2 is: ; (3) Where: P max and ΔP max They are respectively the maximum actual output of the units in T2 and the maximum theoretical adjustment amount. If α2≥1, the primary frequency regulation adjustment amplitude index is qualified.

[0029] 3) Primary frequency modulation adjustment deviation index (α3) The primary frequency regulation deviation index is used to measure the unbiasedness of the primary frequency regulation of the unit. It is stipulated that from the time when the grid frequency changes beyond the primary frequency regulation dead zone of the unit to 60s or until the frequency changes back to the primary frequency regulation dead zone, the average value of the deviation between the actual output of the unit and the theoretical target should be within y2 of the maximum value of the theoretical adjustment load (the y2 value can be set according to the specific situation of the grid).

[0030] α3 is: ; (4) Where: P(t i ), ΔP(t i ), ΔPt i max are the time periods from when the frequency crosses the frequency modulation dead zone to 60s or when the frequency returns to the dead zone. iThe actual output of the unit at the moment, the theoretical adjustment amount and the maximum value of the theoretical adjustment amount; n is the number of sampling points. If α3>1, the primary frequency regulation deviation index is qualified.

[0031] 4) Primary frequency modulation response index (A u ) The primary frequency regulation response index measures the overall effect of the unit's primary frequency regulation by the size of the integrated power. It is stipulated that when the grid frequency changes more than 3 to 60 seconds from the start of the unit's primary frequency regulation dead zone or when the frequency changes back to the primary frequency regulation dead zone, the actual weighted integrated power of the unit's primary frequency regulation must reach more than y3 of the expected integrated power (y3 value can be set according to the specific situation of the grid).

[0032] A u for: ; (5) If A u >1, the primary frequency regulation response index is qualified. Where: Ψ(t) is a weighting function, which weights the time period of concern in the primary frequency regulation process to highlight the primary frequency regulation effect of the unit in this period; W(t) is an adjustment function, which is used to fit the deviation between the actual output change of the unit and the theoretical adjustment amount in the initial stage, and generally uses the first-order inertia link for fitting.

[0033] Weighting function Ψ (t) and the adjustment function W (t) are: ; (6) ; (7) Embodiment 2, Determine indicator weights; The entropy weight method can only reflect the amount of information provided by each evaluation indicator, but cannot reflect the importance of each evaluation indicator. Combining the entropy weight method with the weighting method can reflect objective data information and respect subjective initiative, taking into account the advantages of both. The present invention uses the following method to determine the weight of each evaluation indicator: 1) For the jth indicator, its entropy value e j for: ; (8) Where k = 1 / ln(m), .

[0034] 2) Calculate the entropy weight coefficient p of the jth indicator j for: ; (9) In the formula, β j =1-e j, is the coefficient of difference of index j.

[0035] 3) Calculate the comprehensive weight ω of the jth indicator j for: ; (10) Where 0≤λ j ≤1, subjective and objective compromise coefficient; q j is the jth evaluation determined subjectively by the expert The importance of the indicator.

[0036] For n evaluation indicators, the weight coefficients determined by experts are ranked from small to large in order of importance. The following formula is used to determine: ; (11) In the formula, q k (k=1,2,…n) satisfies .

[0037] Embodiment 3, Collect operational data; Collect the data required for online evaluation of the unit's primary frequency regulation performance, including the unit's primary frequency regulation load response lag time T0, the unit's actual output P(t) at time t, the unit's actual output P0 when the frequency crosses the dead zone, etc. Build a database to save the unit's historical data, and call the historical data to evaluate the unit's primary frequency regulation performance.

[0038] Embodiment 4, Define effective perturbations; The purpose of defining effective disturbance of primary frequency regulation is to determine a method for selecting a frequency band, and use this frequency band to examine whether the primary frequency regulation response characteristics of the unit are qualified. A reasonable definition of effective disturbance is the basis for objectively evaluating the primary frequency regulation capability of the unit. Effective disturbance should fully consider the impact of unit response speed, mechanical dead zone and frequency disturbance on the primary frequency regulation capability of the unit, and combine the possible situations that may occur during the grid-connected operation of the unit to ensure the credibility of the unit assessment indicators.

[0039] The effective perturbation is defined as follows: 1) The time when the frequency crosses the dead zone: The frequency is required to be outside the dead zone value of the primary frequency modulation for at least τ1 (should not be too small). This requirement is set to prevent the calculation result of the assessment index from being subjective because the frequency crosses the dead zone in a short period of time and the unit has not had time to respond.

[0040] 2) The amplitude of the frequency at the initial stage: The maximum value of the frequency within τ2 from the time when the frequency exceeds the primary frequency modulation dead zone should be greater than (50.0+x) Hz (or the minimum value should be less than (50.0-x) Hz), and it should last for more than c (in seconds) (τ2, x, c are given according to the actual situation of the system). This requirement ensures that the primary frequency modulation function of the unit has a sufficiently large excitation to instantly overcome the mechanical dead zone of related devices, and prevents the situation where the index calculation results are greatly affected by the mechanical dead zone when the frequency slightly exceeds the frequency dead zone. At the same time, it also conforms to the nature of the step characteristic of the output change during the primary frequency modulation of the unit.

[0041] Embodiment 5, construct evaluation methods; The response speed index is used to examine the rapidity of the primary frequency regulation; the adjustment amplitude index is used to examine the effectiveness of the unit's primary frequency regulation at the initial stage; the adjustment deviation index is used to examine the unbiasedness of the unit's primary frequency regulation throughout the entire process; the response index index is used to examine the overall effect of the unit's primary frequency regulation process, and is an important supplement to the response speed index, adjustment amplitude index, and adjustment deviation index. Through the coordination of these four indicators, the unit's primary frequency regulation characteristics can be fully examined.

[0042] The primary frequency regulation dead zone of the hydropower unit is set to no more than ±0.05Hz, the speed variation rate is no more than 4%, and the maximum load adjustment limit is ±10% of the rated load.

[0043] 1) Primary frequency regulation response speed index α1: After the grid frequency changes beyond the primary frequency regulation dead zone set by the unit, the load response lag time of the primary frequency regulation of the hydropower unit should be less than 3s, T1=3s. If α1>1, the primary frequency regulation response speed index is qualified; otherwise, it is unqualified.

[0044] 2) Primary frequency regulation adjustment amplitude index α2: The load adjustment amplitude of the unit within 15s should reach 90% of the primary frequency regulation theoretical adjustment load corresponding to the frequency extreme point within 15s, y1=90%, that is, if α2>1, the primary frequency regulation adjustment amplitude index is qualified.

[0045] 3) Primary frequency regulation adjustment deviation index α3: From the time when the grid frequency changes beyond the primary frequency regulation dead zone of the unit to 60s or until the frequency changes back to the primary frequency regulation dead zone, the average value of the deviation between the actual output of the unit and the response target should be within ±8% of the theoretical maximum value of the adjusted load, y2=8%, that is, if α3>1, the primary frequency regulation adjustment deviation index is qualified.

[0046] 4) Primary frequency modulation response index A u : From the time the grid frequency changes beyond the primary frequency regulation dead zone of the unit for 3 to 60 seconds or until the frequency changes back to the primary frequency regulation dead zone, the actual weighted integral power of the primary frequency regulation of the unit must reach more than 90% of the expected integral power, y3=90%, that is, if Au >1, the primary frequency modulation response index is qualified.

[0047] 5) Calculate the weight of each evaluation index, obtain the weight coefficient of each evaluation index, and finally perform weighted summation on each evaluation index to obtain its comprehensive evaluation result.

[0048] Embodiment 6, Publish evaluation results; Based on the calculation results, determine whether the four performance indicators of primary frequency modulation are qualified and give an evaluation.

[0049] If all four performance indicators of primary frequency modulation are qualified, the comprehensive evaluation result R i Determined by the following formula: ; (12) Among them, i=1,2,…,m,j=1,2,…n are the number of evaluation objects and evaluation indicators respectively.

[0050] The evaluation results of various evaluation indicators of primary frequency regulation of hydropower units and comprehensive evaluation results are published, and the evaluation results are saved in the database, which can be compared and analyzed with historical evaluation results.

[0051] In the above method, the evaluation index of the primary frequency regulation performance of the unit is established: from the perspective of stable operation of the power grid and rapid frequency adjustment, the initial period of the primary frequency regulation process should pursue rapidity and effectiveness, and quickly adjust the frequency to a limited range; in the later period, it should pursue unbiasedness to ensure smooth frequency changes.

[0052] In order to evaluate the primary frequency regulation performance of the hydropower unit as comprehensively and accurately as possible, taking into account the operability of the monitoring and implementation of various indicators of the hydropower unit, and comprehensively considering the needs of primary frequency regulation in different time periods, the present invention proposes a response speed index, an adjustment amplitude index, an adjustment deviation index and a response index index for evaluating the primary frequency regulation effect, and establishes a hierarchical primary frequency regulation performance evaluation index system for hydropower units.

[0053] Calculate the weight of each evaluation index and conduct a comprehensive evaluation: combine the entropy weight method with the weighting method to determine the weight of each evaluation index, obtain the weight coefficient of each evaluation index, and finally perform weighted summation on each evaluation index to obtain the comprehensive evaluation result of the primary frequency regulation performance of the hydropower unit.

[0054] The above-mentioned embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The embodiments and features in the embodiments of the present application can be arbitrarily combined with each other without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. An online evaluation method for primary frequency regulation performance of a hydropower unit, characterized in that: The steps include: S1, establish evaluation indicators, including primary frequency modulation response speed indicator, primary frequency modulation adjustment amplitude indicator, primary frequency modulation adjustment deviation indicator and primary frequency modulation response index indicator; S2, determine the indicator weights, combine the entropy weight method with the empowerment method, reflect objective data information, and respect subjective initiative; S3, collects operation data, and collects data required for online evaluation of the primary frequency regulation performance of the unit; S4, define effective disturbance, define effective disturbance of primary frequency modulation, determine a method for selecting a frequency band, and use this frequency band to examine whether the primary frequency modulation response characteristics of the unit are qualified; S5, structural evaluation, the response speed index is used to examine the rapidity of the primary frequency regulation; the adjustment amplitude index is used to examine the effectiveness of the unit's primary frequency regulation at the initial stage; the adjustment deviation index is used to examine the unbiasedness of the unit's primary frequency regulation throughout the entire process; the response index index is used to examine the overall effect of the unit's primary frequency regulation process, which is an important supplement to the response speed index, adjustment amplitude index, and adjustment deviation index; S6, publish the evaluation results, judge whether the four performance indicators of primary frequency modulation are qualified according to the calculation results, and give an evaluation.

2. The method for online evaluation of primary frequency regulation performance of a hydropower unit according to claim 1 is characterized in that: In S1, it is stipulated that the unit primary frequency regulation load response lag time T0 should be less than T1. The T1 value is determined according to the grid demand and the unit is s. The primary frequency modulation response speed index α1 is: ； (1) If α1>1, the primary frequency modulation response speed index is qualified; otherwise, the primary frequency modulation response speed index is unqualified.

3. The method for online evaluation of primary frequency regulation performance of a hydropower unit according to claim 1 is characterized in that: In S1, under ideal conditions, when the grid frequency crosses the dead zone, it is necessary to make precise adjustments according to the change of the unit active output with the frequency, so that the theoretical adjustment amount ΔP(t) is consistent with the actual adjustment amount, that is, (2) Where: σ is the unit adjustment coefficient; is the deviation of frequency relative to the dead zone; P N is the rated capacity of the unit; P (t) is the actual output of the unit at time t; P 0 is the actual output of the unit when the frequency crosses the dead zone. To prevent measurement errors, the average value of the k moments before the frequency crosses the dead zone can be used instead, k∈R, in seconds; The primary frequency regulation adjustment amplitude index is used to measure the unit output adjustment amplitude at the initial stage of primary frequency regulation; it stipulates that the load adjustment amplitude of the unit within T2 should reach y1, the theoretical adjustment load corresponding to the frequency extreme point within this period, and the unit of T2 is s. The values ​​of T2 and y1 can be set according to the specific conditions of the power grid; The primary frequency modulation adjustment amplitude index α2 is: ； (3) Where: P max and ΔP max They are respectively the maximum actual output of the units in T2 and the maximum theoretical adjustment amount; if α2≥1, the primary frequency regulation adjustment amplitude index is qualified.

4. The method for online evaluation of primary frequency regulation performance of a hydropower unit according to claim 1 is characterized in that: In S1, the primary frequency regulation deviation index is used to measure the unbiasedness of the primary frequency regulation of the unit; it is stipulated that from the time when the grid frequency changes beyond the primary frequency regulation dead zone of the unit to 60s or until the frequency changes back to the primary frequency regulation dead zone, the average value of the deviation between the actual output of the unit and the theoretical target should be within y2 of the maximum value of the theoretical adjustment load, and the y2 value is set according to the specific situation of the grid; The primary frequency modulation adjustment deviation index α3 is: (4) Where: P(t i ), ΔP(t i ), ΔPt i max are the time periods from when the frequency crosses the frequency modulation dead zone to 60s or when the frequency returns to the dead zone. i The actual output of the unit at the moment, the theoretical adjustment amount and the maximum value of the theoretical adjustment amount; n is the number of sampling points; if α3>1, the primary frequency adjustment deviation index is qualified.

5. The method for online evaluation of primary frequency regulation performance of a hydropower unit according to claim 1 is characterized in that: In S1, the primary frequency regulation response index index measures the overall effect of the unit's primary frequency regulation by the size of the integrated power. It is stipulated that when the grid frequency changes beyond the primary frequency regulation dead zone of the unit for 3 to 60 seconds or until the frequency changes back to the primary frequency regulation dead zone, the actual weighted integrated power of the unit's primary frequency regulation must reach y3 or more of the expected integrated power, and the y3 value is set according to the specific situation of the grid. Primary frequency modulation response index A u for: ；(5) If A u >1, the primary frequency regulation response index is qualified; where: Ψ(t) is a weighting function, which weights the time period of concern in the primary frequency regulation process to highlight the primary frequency regulation effect of the unit in this period; W(t) is an adjustment function, which is used to fit the deviation between the actual output change of the unit and the theoretical adjustment amount in the initial stage, and the first-order inertia link is used for fitting; Weighting function Ψ (t) and the adjustment function W (t) are: ；(6) ；(7)。 6. The method for online evaluation of primary frequency regulation performance of a hydropower unit according to claim 1 is characterized by: In S2, determine the weight of each evaluation index: For the jth indicator, its entropy value is e j for: (8) Where k = 1 / ln(m), ; Calculate the entropy weight coefficient p of the jth indicator j for: ； (9) In the formula, β j =1-e j , is the coefficient of difference of index j; Calculate the comprehensive weight ω of the jth indicator j for: (10) Where 0≤λ j ≤1, subjective and objective compromise coefficient; q j is the jth evaluation determined subjectively by the expert The importance of the indicator; For n evaluation indicators, the weight coefficients determined by experts are ranked from small to large in order of importance. The following formula is used to determine: ； (11) In the formula, q k (k=1,2,…n) satisfies .

7. The method for online evaluation of primary frequency regulation performance of a hydropower unit according to claim 1 is characterized by: In S3, the data required for online evaluation of the primary frequency regulation performance of the unit are collected, including the unit's primary frequency regulation load response lag time T0, the unit's actual output P(t) at time t, and the unit's actual output P0 when the frequency crosses the dead zone; a database is built to save the unit's historical data, and the historical data can be called to evaluate the unit's primary frequency regulation performance.

8. The method for online evaluation of primary frequency regulation performance of a hydropower unit according to claim 1 is characterized by: In S4, the definition of effective disturbance includes: the time when the frequency crosses the dead zone: the frequency is required to be outside the dead zone value of the first frequency modulation for at least τ1, where τ1 is in seconds; the amplitude reached by the frequency in the initial stage: the frequency is required to be within τ2 from the beginning of exceeding the dead zone of the first frequency modulation, the maximum value should be greater than (50.0+x) Hz, or the minimum value should be less than (50.0-x) Hz, and it should last for more than c, where c is in seconds, and τ2, x, and c are given according to the actual situation of the system.

9. The method for online evaluation of primary frequency regulation performance of a hydropower unit according to claim 1 is characterized in that: In S6, if all four performance indicators of primary frequency modulation are qualified, the comprehensive evaluation result R i Determined by the following formula: (12) Among them, i=1,2,…,m,j=1,2,…n are the number of evaluation objects and evaluation indicators respectively; The evaluation results of various evaluation indicators of primary frequency regulation of hydropower units and the comprehensive evaluation results are published, and the evaluation results are saved in the database for comparative analysis with historical evaluation results.

Images