Hydroelectric generating set debugger primary frequency modulation response control method for simulating additional power of wind power plant in real time

Abstract

The invention belongs to the technical field of cooperative control of a conventional generator set and a new energy unit, and particularly relates to a primary frequency modulation response control method of a hydroelectric generating set speed regulator for simulating additional power of a wind power plant in real time. The method starts with the frequency modulation response mechanism of a hydroelectric generating set and a wind turbine generator, comprehensively considers the action characteristics of a hydroelectric generating set speed regulator and wind power plant additional power control, and can avoid the defect that the hydroelectric generating set and a wind power plant cannot quickly sense the power output mutually in the traditional primary frequency modulation response process. The primary frequency modulation response control of the hydroelectric generating set and the primary frequency modulation response control of the wind power generating set are further coordinated, the performance of providing frequency support by hydroelectric-wind power is improved, and the hydroelectric generating set can sense the additional power of the wind power plant without adding additional communication equipment, so that the coordinated frequency modulation of the hydroelectric generating set and the wind power plant is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of coordinated control of conventional generator sets and new energy generator sets, and specifically relates to a primary frequency modulation response control method for a hydropower generator set speed governor that simulates additional power of a wind farm in real time. Background Art

[0002] In recent years, with the proposal of the "dual carbon goals", my country has begun to plan and build a number of clean energy bases. In the southwest region with sufficient hydropower resources, a pattern of rapid coordinated development of hydropower, wind power and photovoltaic power has been formed. However, the large-scale grid connection of new energy has led to a decline in the frequency stability of the power system, affecting the safe and stable operation of the power system. In order to enhance the stability of the power system, new energy must also be included in the frequency regulation response process. The active power output characteristics of new energy units are relatively flexible, and the spare capacity is large, which can become an important frequency regulation resource for the power system. The primary frequency regulation of the current power system is mainly achieved through the speed regulator of conventional units. After being included in the frequency regulation response process, new energy units are bound to face the problem of coordinating with conventional units to provide frequency support.

[0003] Wind farms and hydropower stations in the clean energy base in southwest my country are geographically close. The active power output of wind power is not limited by the periodicity of solar radiation, and it can generate electricity during the appropriate wind speed period throughout the day. However, wind power is not currently involved in the frequency regulation of the power system. If wind power participates in frequency regulation, its flexible active power output characteristics can be coordinated with the power output characteristics of the speed regulator of the adjacent hydropower station. Therefore, it is necessary to study the coordination of the primary frequency regulation response control process of hydropower-wind power to realize the frequency support technology of hydropower-wind power coordination.

[0004] At present, there have been some studies on the technology of frequency support provided by hydropower and wind power at home and abroad. In terms of frequency support provided by hydropower, existing studies have analyzed and optimized the control process of the speed regulator of the hydropower unit and the suppression process of the water hammer effect when the hydropower unit adjusts the active power. Some scholars have considered the water hammer effect, added the water hammer effect influence link to the speed regulator of the hydropower unit, adjusted the water hammer effect coefficient, and corrected the response function of the speed regulator of the hydropower unit. In terms of frequency support provided by wind power, existing studies have compared and optimized additional power control methods such as droop control, virtual inertia control and virtual synchronous generator control, so that wind turbines can participate in primary frequency regulation. However, the synergistic mechanism of hydropower and wind power in frequency regulation needs further study. Hydropower has good frequency regulation characteristics, and its speed regulator action process is realized by computer control inside the hydropower unit. The output power of wind power is controlled and adjusted by the converter, and the response process is relatively flexible. If we want to achieve coordination between hydropower and wind power in a single frequency modulation process, a key problem is that the frequency modulation time is relatively short. The whole process is only about 15 seconds. In such a short time, it is difficult to issue power instructions to hydropower and wind turbines at the same time and control their coordinated actions. Summary of the invention

[0005] In view of the above problems existing in the prior art, the purpose of the present invention is to provide a method for controlling the primary frequency regulation response of the speed regulator of a hydropower unit that simulates the additional power of a wind farm in real time. The method starts from the frequency regulation response mechanism of the hydropower unit and the wind turbine unit, and comprehensively considers the action characteristics of the hydropower unit speed regulator and the additional power control of the wind farm. It can avoid the disadvantage that the hydropower unit and the wind farm cannot quickly sense each other's power output in the traditional primary frequency regulation response process, and further coordinate the primary frequency regulation response control of the hydropower unit and the wind turbine unit, thereby improving the performance of the frequency support provided by the hydropower-wind power, and can make the hydropower unit sense the additional power of the wind farm without adding additional communication equipment, so as to realize the coordinated frequency regulation of the hydropower unit and the wind farm.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0007] The present invention first considers the following factors comprehensively:

[0008] 1. Various parameters of the speed governor of the hydropower unit;

[0009] 2. Various parameters of wind turbine power control link;

[0010] 3. National standards for hydropower units participating in frequency regulation;

[0011] 4. National standards for wind turbines participating in frequency regulation.

[0012] Based on the above factors, the primary frequency regulation response control method of the hydropower unit speed governor for real-time simulation of the additional power of the wind farm includes the following main steps:

[0013] S1: Analyze the mapping function of wind farm additional power and frequency deviation, and verify the mapping function.

[0014] S2: Add the mapping function of the additional power of the wind farm and the frequency deviation to the control link of the hydropower unit speed governor, so that the turbine can simulate the additional power of the wind farm in real time and adjust its own active power output according to the additional power.

[0015] S3: Regularly synchronize the parameters of the wind farm additional power mapping function with the function parameters of the hydropower unit speed regulator that simulates the wind farm additional power.

[0016] S4: Real-time monitoring of frequency deviation. The hydropower unit calculates the additional power of wind power according to the monitored frequency deviation and the mapping function of step C, and corrects the simulated additional power of wind power according to the difference in frequency deviation between the wind farm and the grid connection point of the hydropower unit.

[0017] S5: According to the calculated additional power of wind power, the active power output controlled by the speed regulator of the hydropower unit changes, so as to realize the coordinated action of the hydropower unit and the wind farm in the primary frequency regulation process.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] This application proposes a primary frequency regulation response control method for a hydropower unit speed governor that simulates the additional power of a wind farm in real time, including parsing the mapping function of the additional power of the wind farm, simulating the additional power of the wind farm; adding the simulated additional power link of the wind farm to the control loop of the hydropower unit, synchronizing the parameters of the power control link of the wind farm, and preliminarily correcting the simulated additional power function of the wind farm; considering the frequency difference of different nodes, re-correcting the simulated additional power of the wind farm, adding a coordinated control strategy to the control loop of the turbine unit, and calculating the power regulation increment of the hydropower unit in the coordinated control strategy, so as to realize the coordinated participation of the hydropower unit and the wind farm in the primary frequency regulation and enhance the frequency stability of the power system. . BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a schematic flow chart of the method steps described in the present invention. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with specific embodiments.

[0022] like Figure 1As shown, the primary frequency modulation response control method of the hydropower unit debugger for real-time simulation of wind farm additional power of the present invention comprises the following steps:

[0023] S1: Analyze the mapping function of wind farm additional power and frequency deviation, and verify the mapping function;

[0024] The additional power mapping function of the wind farm is analyzed, and the additional power formula of the wind farm is expressed as:

[0025]

[0026] In the above formula, ΔP W is the additional power of the wind farm, k d is the differential coefficient, f is the real-time frequency of the wind power grid connection point, k p is the proportional coefficient, f0 is the rated frequency of the power system, f0=50Hz.

[0027] Since the duration of a frequency modulation is 15s, the frequency deviation will reach a steady-state value after the frequency modulation is completed, and the wind power will not return to the initial value immediately after the frequency modulation is completed. Therefore, k can be solved according to the following formula after the frequency modulation of the wind turbine is completed and before the secondary frequency modulation begins. p :

[0028]

[0029] In the above formula, ΔP W.s is the steady-state power of the wind farm after a frequency regulation is completed, f s It is the steady-state frequency of the system after one frequency modulation is completed.

[0030] Since a dead zone is set for wind power to participate in primary frequency regulation, it is only necessary to use the frequency value and sampling interval of the frequency sampling point to obtain k after the frequency crosses the dead zone. d :

[0031]

[0032] In the above formula, ΔP W.d is the additional power of the wind farm corresponding to the second sampling point after the frequency crosses the dead zone, f d is the frequency corresponding to the second sampling point after the frequency crosses the dead zone, t d is the frequency point sampling interval.

[0033] S2: Add the mapping function of the additional power of the wind farm and the frequency deviation to the control link of the hydropower unit speed governor, so that the turbine can simulate the additional power of the wind farm in real time and adjust its own active power output according to the additional power;

[0034] According to the control block diagram of the hydropower unit speed governor, the frequency control function of the hydropower unit can be obtained as follows:

[0035]

[0036] In the above formula, f is the actual frequency of the system, T is the inertia time constant of the hydropower unit, D is the damping coefficient, Δf is the frequency deviation, K D is the differential coefficient, K l is the integration coefficient, K p is the proportionality coefficient, b p is the permanent slip coefficient, T y is the speed regulator time constant, T w is the water flow inertia time constant, ΔP L is the unbalanced power of the system;

[0037] The additional power of the wind farm can be obtained by measuring the frequency, so the control loop of the hydropower unit can also simulate the additional power of the wind farm in real time through the frequency measurement link. In order to simplify the analysis, the above formula is simplified to:

[0038] f=A·[Δf·B-ΔP L ];

[0039] In the above formula, A is the simplified variable coefficient of the hydropower unit speed governor, and B is the variable coefficient of the speed governor frequency control;

[0040] Using the f measured by the frequency measurement link of the hydropower unit in the above formula, the additional power of the wind farm can be simulated in real time. The additional power of the wind farm will directly compensate ΔP L Therefore, the response function of the hydropower unit speed regulator with the wind farm power simulation link added becomes the following form:

[0041] f=A·[Δf·B-ΔP L +ΔP W.s ];

[0042] In the above formula, ΔP W.s The additional power of the wind farm simulated by the control loop of the hydropower unit.

[0043] S3: regularly synchronizing the parameters of the wind farm additional power mapping function with the function parameters of the hydropower unit speed regulator simulating the wind farm additional power;

[0044] The response function of the hydropower unit speed regulator in the wind farm power simulation link in step S2 is transformed into the following form:

[0045]

[0046] In the above formula, k d.s is the differential coefficient of wind farm additional power simulated by hydropower unit, kp.s The additional power proportionality coefficient of the wind farm simulated for the hydropower unit.

[0047] In order to increase the accuracy of simulating the additional power of wind farms, k d.s and k p.s To synchronize, the process is:

[0048] After the additional power strategy of the wind farm is adjusted, it is reported to the dispatch center, and then the dispatch center notifies the hydropower units to adjust the parameter k. d.s and k p.s Update and redetermine k according to the above formula d.s and k p.s The value of

[0049] After initially determining k d.s and k p.s After the value of k is set, the dispatching center sends the additional power curves of the wind farm in the process of frequency modulation two to three times after the parameters are changed to the hydropower station. The hydropower unit uses these sets of curves to adjust k d.s and k p.s After preliminary correction, the corrected k d.s and k p.s Respectively expressed as:

[0050] k d.s =k d +k d.c ;

[0051] k p.s =k p +k p.c ;

[0052] In the above formula, k d.c is the differential coefficient correction value for simulating the additional power of wind farm, k p.c It is the proportional coefficient correction value for simulating the additional power of wind farm.

[0053] In addition to making corrections based on the notification from the dispatch center and the wind power added power curve, the correction k can also be calculated regularly at a specific time (such as zero o'clock) every day. d.c and k p.c , in order to improve the accuracy of simulating the additional power of wind farms.

[0054] S4: Real-time monitoring of frequency deviation, the hydropower unit calculates the additional power of wind power according to the monitored frequency deviation and the mapping function of step S3, and corrects the simulated additional power of wind power according to the difference in frequency deviation between the wind farm and the hydropower unit's respective grid connection points;

[0055] The formula for simulating additional power of wind farm is:

[0056]

[0057] In the above formula, f is the frequency value measured by the hydropower unit at the grid connection point. However, when the power system has frequency deviation, the frequency values ​​of the nodes where the generators are located are different from each other, and there are certain differences in the frequencies of each node. Therefore, there will be errors between the additional power of the wind farm simulated by the hydropower unit and the actual additional power of the wind farm. The frequency difference between the wind farm grid connection point and the hydropower station grid connection point is:

[0058] f d =f W -f H ;

[0059] In the above formula, f d is the frequency difference between the wind power grid connection point and the hydropower grid connection point, f W is the frequency of the wind power grid connection point, f H The frequency of the hydropower grid connection point;

[0060] When the load of the power system does not change suddenly, the frequency is in a steady state. W and f H Equal, f d is 0;

[0061] When the load of the power system changes suddenly, the frequency shifts. d Not 0;

[0062] In the f d When describing, the node frequency difference function is constructed as:

[0063] f d =F1(Z,ΔP L );

[0064] In the above formula, F1(·) is the node frequency difference function, Z is the electrical distance between the wind power grid connection point and the hydropower grid connection point;

[0065] Combining the above equations, the corrected simulated wind farm additional power can be obtained as:

[0066]

[0067] S5: According to the calculated additional power of wind power, the active power output controlled by the speed governor of the hydropower unit changes, so as to realize the synergy between the hydropower unit and the wind farm in the primary frequency regulation process;

[0068] The control strategy for hydropower and wind power to coordinate and participate in primary frequency regulation can be expressed as:

[0069] ΔP H2 =F2(f H ,ΔP W );

[0070] In the above formula, ΔP H2 is the output power adjustment of the prime mover of the hydropower unit in the coordinated control strategy, and F2(·) is the coordinated frequency regulation control strategy function;

[0071] According to the frequency control function of the hydropower unit, the output power regulation function of the prime mover of the hydropower unit can be obtained as follows:

[0072]

[0073] In the above formula, ΔP H It is the output power adjustment value of the prime mover of the hydropower unit under the control of the speed governor;

[0074] In order to enable the hydropower units to implement the coordinated control strategy, it is necessary to H Based on the addition of an increment ΔP H.add , and its calculation formula is:

[0075]

[0076] ΔP H.add By inputting the power command into the power control loop of the hydropower unit, an increment can be added to the guide vane opening of the turbine, so that the turbine unit can meet the power target of the coordinated control.

[0077] The present application proposes a primary frequency regulation response control method for a hydropower unit speed governor that simulates the additional power of a wind farm in real time, including parsing a mapping function of the additional power of the wind farm and simulating the additional power of the wind farm; adding the simulated additional power link of the wind farm to the control loop of the hydropower unit, synchronizing the power control link parameters of the wind farm, and preliminarily correcting the simulated additional power function of the wind farm; considering the frequency difference of different nodes, correcting the simulated additional power of the wind farm again, adding a coordinated control strategy to the control loop of the turbine unit, and calculating the power regulation increment of the hydropower unit in the coordinated control strategy, thereby realizing the coordinated participation of the hydropower unit and the wind farm in the primary frequency regulation and enhancing the frequency stability of the power system.

Claims

1. A method for controlling the primary frequency modulation response of a hydropower unit commissioning device for real-time simulation of wind farm additional power, characterized in that: The method comprises the following steps: S1: Analyze the mapping function of wind farm additional power and frequency deviation, and verify the mapping function; The additional power mapping function of the wind farm is analyzed, and the additional power formula of the wind farm is expressed as: In the above formula, ΔP W is the additional power of the wind farm, k d is the differential coefficient, f is the real-time frequency of the wind power grid connection point, k p is the proportionality coefficient, f0 is the rated frequency of the power system, f0=50Hz; S2: Add the mapping function of the additional power of the wind farm and the frequency deviation to the control link of the hydropower unit speed governor, so that the turbine can simulate the additional power of the wind farm in real time and adjust its own active power output according to the additional power; According to the control block diagram of the hydropower unit speed governor, the frequency control function of the hydropower unit can be obtained as follows: In the above formula, f is the actual frequency of the system, T is the inertia time constant of the hydropower unit, D is the damping coefficient, Δf is the frequency deviation, K D is the differential coefficient, K l is the integration coefficient, K p is the proportionality coefficient, b p is the permanent slip coefficient, T y is the speed regulator time constant, T w is the water flow inertia time constant, ΔP L is the unbalanced power of the system; Simplifying the above formula, we get: f=A·[Δf·B-ΔP L ]; In the above formula, A is the simplified variable coefficient of the hydropower unit speed governor, and B is the variable coefficient of the speed governor frequency control; Using the f measured by the frequency measurement link of the hydropower unit in the above formula, the additional power of the wind farm can be simulated in real time. The additional power of the wind farm will directly compensate ΔP L , the response function of the hydropower unit speed regulator with the wind farm power simulation link added becomes the following form: f=A·[Δf·B-ΔP L +ΔP W.s ]; In the above formula, ΔP W.s The additional power of the wind farm simulated by the control loop of the hydropower unit; S3: regularly synchronizing the parameters of the wind farm additional power mapping function with the function parameters of the hydropower unit speed regulator simulating the wind farm additional power; The response function of the hydropower unit speed regulator in the wind farm power simulation link in step S2 is transformed into the following form: In the above formula, k d.s is the differential coefficient of wind farm additional power simulated by hydropower unit, k p.s The additional power proportionality factor of the wind farm simulated for the hydropower unit; S4: Real-time monitoring of frequency deviation, the hydropower unit calculates the additional power of wind power according to the monitored frequency deviation and the mapping function of step S3, and corrects the simulated additional power of wind power according to the difference in frequency deviation of the wind farm and the hydropower unit's respective grid connection points; The formula for simulating additional power of wind farm is: In the above formula, f is the frequency value measured by the hydropower unit at the grid connection point. The frequency difference between the wind farm grid connection point and the hydropower station grid connection point is: f d =f W -f H ; In the above formula, f d is the frequency difference between the wind power grid connection point and the hydropower grid connection point, f W is the frequency of the wind power grid connection point, f H The frequency of the hydropower grid connection point; When the load of the power system does not change suddenly, the frequency is in a steady state. W and f H Equal, f d is 0; When the load of the power system changes suddenly, the frequency shifts. d Not 0; In the f d When describing, the node frequency difference function is constructed as: f d =F1(Z,ΔP L ); In the above formula, F1(·) is the node frequency difference function, Z is the electrical distance between the wind power grid connection point and the hydropower grid connection point; Combining the above equations, the corrected simulated wind farm additional power can be obtained as: S5: According to the calculated additional power of wind power, the active power output controlled by the speed governor of the hydropower unit changes, so as to realize the synergy between the hydropower unit and the wind farm in the primary frequency regulation process; The control strategy for hydropower and wind power to coordinate and participate in primary frequency regulation can be expressed as: ΔP H2 =F2(f H ,ΔP W ); In the above formula, ΔP H2 is the output power adjustment of the prime mover of the hydropower unit in the coordinated control strategy, and F2(·) is the coordinated frequency regulation control strategy function; According to the frequency control function of the hydropower unit, the output power regulation function of the prime mover of the hydropower unit can be obtained as follows: In the above formula, ΔP H It is the output power adjustment value of the prime mover of the hydropower unit under the control of the speed governor; In ΔP H Based on the addition of an increment ΔP H.add , and its calculation formula is: ΔP H.add The power command is input into the power control loop of the hydropower unit, so that the turbine unit can meet the power target of coordinated control.

2. The primary frequency modulation response control method for a hydropower unit commissioning device for real-time simulation of wind farm additional power according to claim 1 is characterized in that: After the primary frequency regulation of the wind turbine is completed, k can be obtained by solving the following formula before the secondary frequency regulation begins. p : In the above formula, ΔP W.s is the steady-state power of the wind farm after a frequency regulation is completed, f s It is the steady-state frequency of the system after one frequency modulation is completed; After the frequency crosses the dead zone, k is obtained using the frequency value and sampling interval of the frequency sampling point. d : In the above formula, ΔP W.d is the additional power of the wind farm corresponding to the second sampling point after the frequency crosses the dead zone, f d is the frequency corresponding to the second sampling point after the frequency crosses the dead zone, t d is the frequency point sampling interval.

3. The primary frequency modulation response control method for a hydropower unit commissioning device for real-time simulation of wind farm additional power according to claim 1 is characterized in that: In step S3, k d.s and k p.s To synchronize, the process is: After the additional power strategy of the wind farm is adjusted, it is reported to the dispatch center, and then the dispatch center notifies the hydropower units to adjust the parameter k. d.s and k p.s Update and redetermine k according to the above formula d.s and k p.s The value of After initially determining k d.s and k p.s After the value of k is set, the dispatching center sends the additional power curves of the wind farm in the process of frequency modulation two to three times after the parameters are changed to the hydropower station. The hydropower unit uses these sets of curves to adjust k d.s and k p.s After preliminary correction, the corrected k d.s and k p.s Respectively expressed as: k d.s =k d +k d.c ; k p.s =k p +k p.c ; In the above formula, k d.c is the differential coefficient correction value for simulating the additional power of wind farm, k p.c It is the proportional coefficient correction value for simulating the additional power of wind farm.

4. The primary frequency modulation response control method for a hydropower unit commissioning device for real-time simulation of wind farm additional power according to claim 3 is characterized in that: The modified k is calculated regularly at a specific time every day d.c and k p.c .

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