New energy station AVC test parameter optimization method, device, equipment and storage medium

Abstract

The present invention discloses a method, device, equipment and storage medium for optimizing the AVC test parameters of a new energy station, obtains the voltage history data of a recent period, finds the characteristic period of a day of the power grid and the characteristic period of the new energy station, obtains the maximum and minimum values ​​of the voltage effective value in the characteristic period, and calculates the difference between the maximum and minimum values; obtains the normal distribution density function according to all the differences, selects the voltage value corresponding to the preset voltage fluctuation amplitude range in the normal distribution density function as the voltage regulation dead zone, and then uses the power grid system characterization impedance to correct the AVC voltage regulation dead zone. The present invention can avoid manual continuous trial of parameters on site, improves the network-related test efficiency of the new energy station, and the results are accurate and reliable.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy grid connection, and in particular relates to a method, device, equipment and storage medium for optimizing AVC test parameters of a new energy station. Background Art

[0002] In the new power system, the voltage control capability and reactive power control capability of wind power, photovoltaic and other new energy stations need to meet certain standard requirements to achieve grid connection. Since the power grid is dynamic, power plants need to balance the active power and reactive power of the power grid load in real time. The external characteristics of new energy stations are significantly different at different electrical locations in the power grid. When the same reactive power is injected into the grid connection point, the characteristics of node voltage change are also different. In addition, the output of new energy stations is closely related to weather conditions. Some drastic weather changes are difficult to predict. These factors have led to an increase in the frequency and amplitude of grid disturbances. In areas with high penetration rates, the disordered and high-frequency fluctuations in the grid voltage make it difficult for new energy stations to meet the station grid-related test standards. In order to improve the efficiency of grid-related tests, especially voltage control, it is necessary to optimize the grid-related test parameters based on the historical data and electrical characteristics of the station.

[0003] In a typical new energy station grid-related test, the automatic power control (AVC) system has the following adjustment process:

[0004] a) AVC obtains voltage command U f , detect the outgoing line voltage of the station. If the outgoing line voltage of the station is below U f ±U d Within (U d Indicates voltage regulation dead zone), the instruction is invalid; otherwise, the voltage adjustment calculation starts;

[0005] b) Calculate the grid characterization impedance Z using previously acquired grid data r , and its calculation formula is as follows:

[0006]

[0007] Among them, U + ,ΣQ + Respectively represent the current outgoing line voltage, reactive power, U _ ,ΣQ _ Respectively represent the previous outgoing line voltage and reactive power;

[0008] c) Estimate the reactive power value Q that needs to be adjusted t :

[0009]

[0010] The parameter U used in the above adjustment process d and Z rOn-site test personnel are required to make continuous corrections through manual trial and error, resulting in low test efficiency. Summary of the invention

[0011] Based on this, it is necessary to provide a method, device, equipment and storage medium for optimizing AVC test parameters of new energy stations to address the problem of low efficiency of network-related tests in new energy stations.

[0012] In a first aspect, a method for optimizing AVC test parameters of a new energy station is provided, the method comprising: obtaining historical voltage data for a recent period of time, finding characteristic time periods of a day for the power grid and characteristic time periods for the new energy station, obtaining the maximum and minimum values ​​of the effective voltage in the characteristic time periods, and calculating the difference between the maximum and minimum values; obtaining a normal distribution density function based on all the differences, and selecting a voltage value corresponding to a voltage fluctuation amplitude range that exceeds a preset range in the normal distribution density function as a voltage regulation dead zone.

[0013] Among them, the normal distribution density function is obtained by fitting, specifically:

[0014]

[0015] Among them, the value used for fitting is F(u)={u 1 ,u 2 ,.......u m , -u 1 , -u 2 ,.......-u m}, is the difference between the maximum and minimum voltages in each characteristic period.

[0016] Among them, the characteristic time periods include: peak power consumption of the power grid, trough power consumption, maximum power of new energy stations, median power of new energy stations, and periods of zero power.

[0017] The preset voltage fluctuation amplitude range is 80%, but this value can be adjusted accordingly according to local actual conditions and needs.

[0018] In one of the embodiments, several time points are selected in a characteristic time period, and the grid characterization impedance value at each time point is calculated; the root mean square of all the above impedance values ​​is taken to obtain the system impedance used to calculate reactive power.

[0019] In one of the embodiments, several time points are selected in a characteristic time period, and the system impedance is used to calculate the given value of reactive power when adjusting the corresponding rated voltage at each time point, the corresponding reactive value of the actual power grid, and the difference between the two, to obtain the difference ratio, which refers to the ratio of the difference to the corresponding reactive value of the actual power grid; the maximum value of the absolute value of the difference ratio is selected; and the voltage regulation dead zone is corrected according to the maximum value.

[0020] In one embodiment, if the voltage adjustment span does not exceed N KV at one time, the voltage regulation dead zone is corrected according to the maximum value by taking the correction value ΔU z =N*η max ; where η max is the maximum absolute value of the difference ratio.

[0021] In one of the embodiments, the voltage regulation dead zone is corrected according to the maximum value, and the corrected voltage regulation dead zone is the sum of the voltage value corresponding to the voltage exceeding the preset voltage fluctuation amplitude range in the normal distribution density function and the correction value.

[0022] In a second aspect, a new energy station AVC test parameter optimization device is provided, the device comprising:

[0023] The data acquisition module is used to obtain the voltage history data of a recent period, find out the characteristic time period of the power grid and the characteristic time period of the new energy station, and obtain the maximum and minimum values ​​of the effective voltage value in the characteristic time period;

[0024] A calculation module is used to calculate the difference between the maximum value and the minimum value, and obtain a normal distribution density function according to all the differences;

[0025] The determination module is used to select a voltage value corresponding to a voltage fluctuation amplitude range exceeding a preset voltage fluctuation amplitude range in a normal distribution density function and use it as a voltage regulation dead zone.

[0026] In one of the embodiments, a correction module is also included, which is used to select several time points in a characteristic time period and calculate the grid characterization impedance value at each time point; take the root mean square of all the above impedance values ​​to obtain the system impedance used to calculate reactive power; use the system impedance to calculate the given value of reactive power when adjusting the corresponding rated voltage at each time point, the corresponding reactive value of the actual grid and the difference between the two, and obtain the difference ratio, which refers to the ratio of the difference to the corresponding reactive value of the actual grid; select the maximum value of the absolute value of the difference ratio; and correct the voltage regulation dead zone according to the maximum value.

[0027] In a third aspect, a computer device includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method steps described in the method for optimizing AVC test parameters of new energy stations described in the first aspect are implemented.

[0028] In a fourth aspect, a computer-readable storage medium stores a computer program thereon, and when the computer program is executed by a processor, the method steps described in the method for optimizing AVC test parameters of new energy stations described in the first aspect are implemented.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] The present invention utilizes the normal distribution law existing in the historical data and obtains the voltage regulation dead zone through the normal distribution density function, thereby avoiding continuous correction by manual attempts and improving the grid-related test efficiency of new energy sites. At the same time, in order to improve the accuracy, it is also proposed to use the grid characterization impedance to correct the voltage regulation dead zone, so that the performance is more optimized and easier to match the local grid characteristics, thereby meeting the requirements of the grid-related performance test of new energy sites. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of a method for optimizing AVC test parameters of a new energy station in one embodiment of the present invention;

[0032] Figure 2 It is a flow chart of a method for optimizing AVC test parameters of a new energy station in one embodiment of the present invention;

[0033] Figure 3 It is a structural schematic diagram of an AVC test parameter optimization device for a new energy station in one embodiment of the present invention;

[0034] Figure 4 It is a structural schematic diagram of an AVC test parameter optimization device for a new energy station in one embodiment of the present invention. DETAILED DESCRIPTION

[0035] The AVC test parameter optimization method, device, equipment and storage medium for new energy stations provided by the present invention are intended to solve the problem of low efficiency of network-related tests in existing new energy stations. The technical scheme of the present invention and how the technical scheme of the present invention solves the above-mentioned technical problems will be described in detail below through embodiments and in combination with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of this application, not all of them. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments.

[0036] In a typical station grid-connected test, when the station outgoing line voltage is U f ±U ir , AVC target regulation voltage is U f hour:

[0037] a) Grid connection point voltage U f ±U ir in U f ±U d Outside the range, that is, U ir >U d , AVC will immediately perform voltage regulation;

[0038] b) Grid connection point voltage U f ±U ir in Uf ±U d Within the range, that is, U ir ≤U d , AVC will not adjust. In this way, the maximum value of the steady-state regulation deviation E bmax It can be expressed as:

[0039]

[0040] From formula (3), we can see that E bmax with U d Proportional to U d The larger the setting, the larger the maximum value of the steady-state regulation deviation. d The smaller it is, the smaller the maximum value of the steady-state regulation deviation is. d →0: E bmax =0, the adjustment accuracy is the highest.

[0041] But the grid voltage is constantly fluctuating, that is, U ir >0,U d →0, U ir >U d ; In this way, AVC will enter a continuous adjustment cycle, AVC will continuously issue voltage adjustment instructions, and the voltage and reactive power will continuously adjust up and down and fluctuate. The voltage is always in dynamic adjustment, and the voltage is unstable. Therefore, the appropriate U d The value can satisfy the smaller E bmax requirements, and can avoid most of the grid disturbances, that is, U ir ≤U d , it is best to keep the voltage relatively stable. Therefore, when the amplitude value U of the grid voltage fluctuation within a certain period of time ir After confirmation, U d The minimum value of U is determined. ir , its range can be determined by statistical laws.

[0042] Figure 1 The flowchart of the AVC test parameter optimization method of a new energy station in one embodiment is as follows:

[0043] S101. Obtain historical voltage data for a recent period of time, find out the characteristic time periods of the power grid and the characteristic time periods of new energy stations in a day, obtain the maximum and minimum values ​​of the effective voltage value in the characteristic time periods, and calculate the difference between the maximum and minimum values.

[0044] Among them, the voltage history data of the past month can be checked through the AVC / AGC background to find out the characteristic time periods of the power grid and the characteristic time periods of new energy stations. The characteristic time periods here can be selected from the peak of power consumption of the power grid, the trough of power consumption, the maximum power of the new energy station, the median power, and the time period of zero power. In the above time period, read the maximum and minimum values ​​of the effective value of the voltage for each 30 minutes, and calculate the difference between the maximum and minimum values ​​of the voltage. For the convenience of sorting, you can fill in the following tables similar to Table 1 and Table 2, where Table 1 represents the voltage difference table of the first day, and Table 2 represents the voltage difference table of the 30th day (the last day for statistics).

[0045] Table 1 Voltage difference table on the first day

[0046]

[0047] Table 2 Voltage difference table on the 30th day

[0048]

[0049]

[0050] S102 , obtaining a normal distribution density function according to all the differences, and selecting a voltage value corresponding to a voltage fluctuation amplitude range exceeding a preset voltage fluctuation amplitude range in the normal distribution density function as a voltage regulation dead zone.

[0051] Let F(u)={u 1 ,u 2 ,.......u 150 , -u 1 , -u 2 ,.......-u 150}, since the voltage disturbance is random, the amplitude is also random, and random events generally obey the normal distribution. Therefore, the present invention uses the normal distribution function to describe the variation law of the voltage fluctuation amplitude. Using MATLAB, with y=0 as the symmetry axis, the normal distribution density function of F(u) is fitted:

[0052]

[0053] According to the local actual situation and demand, f(u) = 0.8, which is 80% of the voltage fluctuation range, and u = u 0 (Take the positive value solution), so we get the voltage dead zone value U d1 =u 0 , theoretically. The initial value of the voltage dead zone is U d1 The stability of voltage fluctuations can be guaranteed for more than 80% of the time period.

[0054] Considering that the power grid is dynamic and its operation mode is changing, the grid characterization impedance Zr will also change, and the reactive power command given by the voltage regulation is obtained through a fixed Z r0 , calculated by formula (2), and the current Z r The reactive power that should be given has a deviation, so the voltage may not reach the given value during regulation, and there is a deviation ΔU z .

[0055]

[0056] This results in the voltage dead zone being set from responding to U d1 The voltage change is reduced to U d1 -ΔU z Therefore, in one embodiment, for Z r The changes proposed to U d Make corrections.

[0057] Figure 2 Schematic diagram of a flow chart of a method for optimizing AVC test parameters of a new energy station in an embodiment, the method further includes the following steps:

[0058] S103, selecting a number of time points in the characteristic period, and calculating the grid characterization impedance value at each time point; taking the root mean square of all the above impedance values ​​to obtain the system impedance used to calculate reactive power.

[0059] Here, referring to step S101, in the 30-minute periods of the peak and valley of power consumption of the power grid, the maximum power of the new energy station, the median power, and the power output 0 of the power grid in a day, find 5 points every 5 minutes, and calculate the Z of each time period. r value:

[0060]

[0061] .............

[0062]

[0063] Take the RMS of the above 25 impedance values Z rr This is the system impedance used to calculate reactive power.

[0064] S104, using the system impedance to calculate the given value of reactive power when adjusting the corresponding rated voltage at each time point, the reactive value corresponding to the actual power grid, and the difference between the two, and obtain the difference ratio, which refers to the ratio of the difference to the reactive value corresponding to the actual power grid.

[0065] In one embodiment, Z rrMake parameters in these different time periods, calculate the given value of adjusting the 1KV voltage reactive power, the corresponding reactive power value of the actual power grid, the reactive power difference and the difference ratio, and fill them in the following Table 3.

[0066] Table 3 Reactive power difference table for power grid characteristic period

[0067]

[0068]

[0069] In the above table, U n+ ,ΣQ n+ They are respectively the voltage value and reactive power value at the instant with identification number n (n=1, 2..., 25).

[0070] S105, select the maximum absolute value of the difference ratio, that is:

[0071]

[0072] According to formula (5), ΔU z with U f -U + In actual network testing, the voltage adjustment span is generally no more than 2KV at a time, that is, |U f -U + |≤2, so take ΔU corresponding to 2KV z =2*η max .

[0073] In this way, the corrected voltage dead zone value is:

[0074] U d =U d1 +ΔU z =u 0 +2*η max .

[0075] Figure 3 FIG. 1 is a schematic diagram of the structure of an AVC test parameter optimization device for a new energy station provided in an embodiment. Figure 3 As shown, the device comprises:

[0076] The data acquisition module is used to obtain the voltage history data of a recent period, find out the characteristic time period of the power grid and the characteristic time period of the new energy station, and obtain the maximum and minimum values ​​of the effective voltage value in the characteristic time period;

[0077] A calculation module is used to calculate the difference between the maximum value and the minimum value, and obtain a normal distribution density function according to all the differences;

[0078] The determination module is used to select a voltage value corresponding to a voltage fluctuation amplitude range exceeding a preset voltage fluctuation amplitude range in a normal distribution density function and use it as a voltage regulation dead zone.

[0079] Figure 4 It is a structural schematic diagram of an AVC test parameter optimization device for a new energy station provided in an embodiment. In this embodiment, the device also includes a correction module, which is used to select several time points in a characteristic time period and calculate the grid characterization impedance value at each time point; take the root mean square of all the above impedance values ​​to obtain the system impedance used to calculate reactive power; use the system impedance to calculate the given value of reactive power when adjusting the corresponding rated voltage at each time point, the corresponding reactive value of the actual grid, and the difference between the two, and obtain the difference ratio, which refers to the ratio of the difference to the corresponding reactive value of the actual grid; select the maximum value of the absolute value of the difference ratio; and correct the voltage regulation dead zone according to the maximum value.

[0080] For the specific definition of a new energy station AVC test parameter optimization device, please refer to the definition of the new energy station AVC test parameter optimization method mentioned above, which will not be repeated here. Each module in the above-mentioned new energy station AVC test parameter optimization device can be implemented in whole or in part by software, hardware and a combination thereof. The above-mentioned modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0081] In one embodiment, a computer device is provided, which includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the method steps described in the above-mentioned new energy station AVC test parameter optimization method are implemented.

[0082] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the method steps described in the above-mentioned new energy station AVC test parameter optimization method are implemented.

[0083] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0084] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A method for optimizing AVC test parameters of a new energy station, characterized in that: The method includes: obtaining voltage history data for the past month, finding out characteristic time periods of the power grid and the characteristic time periods of new energy stations, obtaining the maximum and minimum values ​​of the voltage effective value in the characteristic time periods, and calculating the difference between the maximum and minimum values; obtaining a normal distribution density function based on all the differences, and selecting a voltage value corresponding to a preset voltage fluctuation amplitude range in the normal distribution density function as a voltage regulation dead zone; Select several time points in the characteristic period and calculate the grid characterization impedance value at each time point; take the root mean square of all the above grid characterization impedance values ​​to obtain the system impedance used to calculate reactive power; A number of time points are selected in a characteristic time period, and the system impedance is used to calculate the given value of reactive power when adjusting the corresponding rated voltage at each time point, the corresponding reactive value of the actual power grid, and the difference between the two, to obtain the difference ratio, which refers to the ratio of the difference to the corresponding reactive value of the actual power grid; the maximum value of the absolute value of the difference ratio is selected; and the voltage regulation dead zone is corrected according to the maximum value.

2. The AVC test parameter optimization method for new energy stations according to claim 1 is characterized in that: in, The normal distribution density function is obtained by fitting, specifically: The numerical value F(u) used for fitting is {u1, u2, ..., u m , -u1, -u2, ..., -u m }, is the difference between the maximum and minimum voltages in each characteristic period.

3. The AVC test parameter optimization method for new energy stations according to claim 1 is characterized in that: Characteristic time periods include: peak power consumption of the power grid, trough power consumption, maximum power of new energy stations, median power of new energy stations, and periods of zero power.

4. The method for optimizing AVC test parameters of a new energy station according to claim 1, characterized in that: If the voltage adjustment span does not exceed N KV at one time, the method for correcting the voltage regulation dead zone according to the maximum value is: take the correction value as ΔU z =N*η max ; where η max is the maximum absolute value of the difference ratio.

5. The method for optimizing AVC test parameters of a new energy station according to claim 4 is characterized in that: The voltage regulation dead zone is corrected according to the maximum value, and the corrected voltage regulation dead zone is the sum of the voltage value corresponding to the voltage exceeding the preset voltage fluctuation amplitude range in the normal distribution density function and the correction value.

6. A new energy station AVC test parameter optimization device, characterized in that: The device includes: The data acquisition module is used to obtain the voltage history data of the past month, find out the characteristic time period of the power grid and the characteristic time period of the new energy station, and obtain the maximum and minimum values ​​of the effective voltage value in the characteristic time period; A calculation module is used to calculate the difference between the maximum value and the minimum value, and obtain a normal distribution density function according to all the differences; A determination module is used to select a voltage value corresponding to a voltage fluctuation amplitude range exceeding a preset voltage fluctuation amplitude range in a normal distribution density function and use it as a voltage regulation dead zone; It also includes a correction module, which is used to select several time points in the characteristic time period and calculate the power grid characterization impedance value at each time point; take the root mean square of all the above power grid characterization impedance values ​​to obtain the system impedance used to calculate reactive power; use the system impedance to calculate the given value of reactive power when adjusting the corresponding rated voltage at each time point, the corresponding reactive value of the actual power grid and the difference between the two, and obtain the difference ratio, which refers to the ratio of the difference to the corresponding reactive value of the actual power grid; select the maximum value of the absolute value of the difference ratio; and correct the voltage regulation dead zone according to the maximum value.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the method steps described in the new energy station AVC test parameter optimization method according to any one of claims 1 to 5 are implemented.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method steps described in the method for optimizing AVC test parameters of new energy stations according to any one of claims 1 to 5 are implemented.

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