Method, device and equipment for evaluating reactive power reserve of wind power plant in extreme scene

Abstract

The invention provides a reactive power reserve assessment method, device and equipment for a wind power plant in an extreme scene, and relates to the technical field of power systems and automation. The method comprises the following steps: acquiring reactive power reserve basic data of reactive power equipment of a wind power plant, reactive power demand quantity per kilovolt voltage change and maximum voltage change quantity; respectively calculating capacitive reactive power reserve and inductive reactive power reserve according to the reactive power reserve basic data of the reactive power equipment of the wind power plant; respectively calculating capacitive reactive power demand quantity and inductive reactive power demand quantity according to the reactive power demand quantity and the maximum voltage variation quantity of each kilovolt voltage change; wherein the maximum voltage variable quantity comprises a capacitive compensation maximum voltage variable quantity and an inductive compensation maximum voltage variable quantity; and obtaining a reactive power reserve evaluation result of the wind power plant according to the capacitive reactive power reserve, the inductive reactive power reserve, the capacitive reactive power demand and the inductive reactive power demand. The reactive power reserve of the wind power plant can be evaluated.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems and automation, and particularly to a method, device, and equipment for evaluating the reactive power reserve of a wind farm under extreme scenarios. Background Art

[0002] With the rapid development of wind power, the strong volatility and uncertainty of wind power generation have made large-scale wind power integration areas typically characterized by high wind power penetration and weak local power grids. Under the condition of high-penetration wind power access, extreme operating scenarios composed of extreme meteorological conditions such as floods, cold snaps, and multi-day periods of little wind and light accompanied by equipment failures often have a small probability of occurrence but pose great potential hazards. There may be unknown weak points in the power grid security. In particular, the change in wind power under extreme operating scenarios further leads to a sharp increase or decrease in the grid voltage, which will inevitably cause a series of voltage quality problems.

[0003] At present, the reactive power voltage control systems (AVC systems) of most wind farms perform reactive power compensation and voltage regulation by controlling the on-site dynamic reactive power compensation devices and the reactive power output of the turbines themselves. However, wind farms only monitor the reactive power operating state and do not understand the reactive power reserve capacity of the wind farms, making it difficult to achieve reasonable regulation of reactive power voltage under extreme operating scenarios.

[0004] Most of the existing reactive power reserve evaluation technologies start from the overall power system and analyze the reactive power reserve situation of substations, without studying the reactive power reserve at the substation level such as wind farms or photovoltaic power plants. Moreover, there is no clear definition and calculation formula for the dynamic reactive power reserve capacity, resulting in the inability to evaluate the reactive power reserve of wind farms.

[0005] Therefore, there is an urgent need for a method capable of evaluating the reactive power reserve of wind farms. Summary of the Invention

[0006] Embodiments of the present invention provide a method, device, and equipment for evaluating the reactive power reserve of a wind farm under extreme scenarios to solve the problem of inability to evaluate the reactive power reserve of a wind farm.

[0007] In a first aspect, embodiments of the present invention provide a method for evaluating the reactive power reserve of a wind farm under extreme scenarios, including:

[0008] Obtaining the basic data of the reactive power reserve of the reactive power equipment in the wind farm, the reactive power demand per kilovolt voltage change, and the maximum voltage change; wherein, the basic data of the reactive power reserve of the reactive power equipment in the wind farm includes the operating parameters of the reactive power equipment in the wind farm, the maximum reactive power output of the wind turbines, the minimum reactive power output of the wind turbines, the maximum reactive power output of the SVG device, and the minimum reactive power output of the SVG device;

[0009] Calculate the capacitive reactive power reserve and inductive reactive power reserve respectively according to the basic data of the reactive power reserve of the reactive power equipment in the wind farm;

[0010] Calculate the capacitive reactive power demand and inductive reactive power demand respectively according to the reactive power demand per kilovolt voltage change and the maximum voltage change; among them, the maximum voltage change includes the maximum voltage change of capacitive compensation and the maximum voltage change of inductive compensation;

[0011] Obtain the reactive power reserve evaluation result of the wind farm according to the capacitive reactive power reserve, inductive reactive power reserve, capacitive reactive power demand and inductive reactive power demand.

[0012] In a possible implementation manner, the operating parameters of the reactive power equipment in the wind farm include the output power of the SVG device, the output power of the wind turbine generator set, the number of unconnected capacitors, the number of unconnected reactors, the rated reactive power of the capacitor, and the rated reactive power of the reactor;

[0013] Calculate the capacitive reactive power reserve and inductive reactive power reserve respectively according to the basic data of the reactive power reserve of the reactive power equipment in the wind farm, including:

[0014] Calculate the capacitive reactive power reserve according to the rated reactive power of the capacitor, the number of unconnected capacitors, the minimum output reactive power of the fan, the minimum output reactive power of the SVG device, the output power of the wind turbine generator set and the output power of the SVG device;

[0015] Calculate the inductive reactive power reserve according to the rated reactive power of the reactor, the number of unconnected reactors, the maximum output reactive power of the fan, the maximum output reactive power of the SVG device, the output power of the wind turbine generator set and the output power of the SVG device.

[0016] In a possible implementation manner, the process of obtaining the maximum output reactive power of the fan and the minimum output reactive power of the fan includes:

[0017] Apply excitation current to each fan;

[0018] Increase the excitation current of each fan at a preset interval. When the overexcitation limit alarm is issued by the fan, determine the power at this time as the maximum output reactive power of the fan;

[0019] Calculate the maximum output reactive power of the fan according to the maximum output reactive power of each fan;

[0020] Decrease the excitation current of each fan at a preset interval. When the underexcitation limit alarm is issued by the fan, determine the power at this time as the minimum output reactive power of the fan;

[0021] The minimum reactive power output of the fan is calculated based on the minimum value of the reactive power output of each fan.

[0022] In a possible implementation, the process of obtaining the maximum reactive power output of the SVG device and the minimum reactive power output of the SVG device includes:

[0023] Changing the control angle of the SVG device;

[0024] Increasing the control angle of the SVG device at a preset interval. When the SVG device issues a minimum output limit alarm, the power at this time is determined as the minimum reactive power output of the SVG device;

[0025] Decreasing the control angle of the SVG device at a preset interval. When the SVG device issues a maximum output limit alarm, the power at this time is determined as the maximum reactive power output of the SVG device.

[0026] In a possible implementation, the process of obtaining the reactive power demand per kilovolt voltage change includes:

[0027] Obtaining the current voltage value and the current reactive power value at the connection point of the AVC system;

[0028] Performing a step test on the voltage command value at the connection point of the AVC system to obtain the voltage value after the step test and the reactive power value after the step test;

[0029] Calculating the reactive power demand per kilovolt voltage change based on the current voltage value and the current reactive power value, the voltage value after the step test, and the reactive power value after the step test.

[0030] In a possible implementation, the process of obtaining the maximum voltage change amount includes:

[0031] Obtaining the steady-state voltage of the bus before the fault and the minimum value of the bus voltage during the fault;

[0032] Calculating the maximum capacitive compensation voltage change amount based on the steady-state voltage of the bus before the fault and the minimum value of the bus voltage during the fault;

[0033] Obtaining the upper limit of the voltage command interval at the connection point of the AVC system and the corresponding bus voltage value;

[0034] Calculating the maximum inductive compensation voltage change amount based on the upper limit of the voltage command interval at the connection point of the AVC system and the corresponding bus voltage value.

[0035] In a possible implementation, calculating the capacitive reactive power demand and the inductive reactive power demand based on the reactive power demand per kilovolt voltage change and the maximum voltage change amount respectively includes:

[0036] Calculate the capacitive reactive power demand based on the reactive power demand per kilovolt voltage change and the maximum voltage change of capacitive compensation;

[0037] Calculate the inductive reactive power demand based on the reactive power demand per kilovolt voltage change and the maximum voltage change of inductive compensation.

[0038] In a possible implementation, obtain the reactive power reserve evaluation result of the wind farm according to the capacitive reactive power reserve, inductive reactive power reserve, capacitive reactive power demand, and inductive reactive power demand, including:

[0039] When the capacitive reactive power reserve is greater than or equal to the capacitive reactive power demand, the capacitive reactive power reserve during capacitive compensation of the wind farm meets the requirements of grid capacitive reactive voltage regulation;

[0040] When the capacitive reactive power reserve is less than the capacitive reactive power demand, the capacitive reactive power reserve during capacitive compensation of the wind farm does not meet the requirements of grid capacitive reactive voltage regulation, and capacitive reactive compensation equipment needs to be added;

[0041] When the absolute value of the inductive reactive power reserve is greater than or equal to the absolute value of the inductive reactive power demand, the inductive reactive power reserve during inductive compensation of the wind farm meets the requirements of grid inductive reactive voltage regulation;

[0042] When the absolute value of the inductive reactive power reserve is less than the absolute value of the inductive reactive power demand, the inductive reactive power reserve during inductive compensation of the wind farm does not meet the requirements of grid inductive reactive voltage regulation, and inductive reactive compensation equipment needs to be added.

[0043] In a second aspect, an embodiment of the present invention provides a reactive power reserve evaluation device for a wind farm in an extreme scenario, including:

[0044] A data acquisition module for acquiring the basic data of the reactive power reserve of the wind farm's reactive power equipment, the reactive power demand per kilovolt voltage change, and the maximum voltage change; wherein, the basic data of the reactive power reserve of the wind farm's reactive power equipment includes the operating parameters of the wind farm's reactive power equipment, the maximum value of the reactive power output by the fan, the minimum value of the reactive power output by the fan, the maximum value of the reactive power output by the SVG device, and the minimum value of the reactive power output by the SVG device;

[0045] A reactive power reserve calculation module for calculating the capacitive reactive power reserve and the inductive reactive power reserve respectively according to the basic data of the reactive power reserve of the wind farm's reactive power equipment;

[0046] A reactive power demand calculation module is used to calculate the capacitive reactive power demand and the inductive reactive power demand according to the reactive power demand per kilovolt voltage change and the maximum voltage change respectively; wherein, the maximum voltage change includes the maximum voltage change for capacitive compensation and the maximum voltage change for inductive compensation;

[0047] An evaluation module is used to obtain the reactive power reserve evaluation result of the wind farm according to the capacitive reactive power reserve, the inductive reactive power reserve, the capacitive reactive power demand and the inductive reactive power demand.

[0048] In a third aspect, an embodiment of the present invention provides an electronic device, including a memory and a processor, the memory stores a computer program, and when the processor executes the computer program, the method in the first aspect or any possible implementation manner of the first aspect is implemented.

[0049] In the embodiment of the present invention, by analyzing the operating conditions of the reactive power equipment in the wind farm, calculating the capacitive reactive power reserve, the inductive reactive power reserve, the capacitive reactive power demand and the inductive reactive power demand of the wind farm under the extreme operating scenario where all new energy powers such as wind power and photovoltaic power in the local area are cut off, and evaluating the reactive power reserve of the wind farm according to the capacitive reactive power reserve, the inductive reactive power reserve, the capacitive reactive power demand and the inductive reactive power demand, so as to judge whether the reactive power reserve of the wind farm meets the requirements of rapid voltage change in extreme cases. Description of the Drawings

[0050] Figure 1 is the implementation flowchart of the reactive power reserve evaluation method for the wind farm under the extreme scenario provided by the embodiment of the present invention;

[0051] Figure 2 is the logical block diagram of the reactive power reserve evaluation method for the wind farm under the extreme scenario provided by the embodiment of the present invention;

[0052] Figure 3 is the bus voltage curve diagram of the Wanhui Wind Farm under the condition that all other wind farms and photovoltaic power plants in the substation where the Wanhui Wind Farm is located are cut off at the machine terminal provided by the embodiment of the present invention;

[0053] Figure 4 is the structural schematic diagram of the reactive power reserve evaluation device for the wind farm under the extreme scenario provided by the embodiment of the present invention;

[0054] Figure 5 is the schematic diagram of the electronic device provided by the embodiment of the present invention. Detailed Embodiments

[0055] The embodiments of the present invention will be described in detail below with reference to the drawings.

[0056] See Figure 1, which shows the implementation flowchart of the reactive power reserve evaluation method for a wind farm in an extreme scenario provided by an embodiment of the present invention. Figure 2 It is a logic block diagram of the reactive power reserve evaluation method for a wind farm in an extreme scenario provided by an embodiment of the present invention, and is described in detail as follows:

[0057] Step 101: Obtain the basic data of the reactive power reserve of the wind farm's reactive power equipment, the reactive power demand per kilovolt voltage change, and the maximum voltage change; among them, the basic data of the reactive power reserve of the wind farm's reactive power equipment includes the operating parameters of the wind farm's reactive power equipment, the maximum reactive power output of the fan, the minimum reactive power output of the fan, the maximum reactive power output of the SVG device, and the minimum reactive power output of the SVG device.

[0058] In this embodiment, the basic data of the reactive power reserve is used to calculate the reactive power reserve capacity of the wind farm. Among them, the operating parameters of the reactive power equipment can reflect the actual reactive power output of the wind farm's reactive power equipment in the current operating state and the equipment input situation. By obtaining the maximum reactive power output of the fan and the minimum reactive power output of the fan, the reactive power output range of the fan under extreme conditions is obtained, which is used to calculate the maximum reactive power and the minimum reactive power that the wind farm can provide in an extreme operating scenario. By obtaining the maximum reactive power output of the SVG device and the minimum reactive power output of the SVG device, the reactive power output range of the SVG device under extreme conditions is obtained, which is used to calculate the maximum reactive power and the minimum reactive power that the wind farm can provide in an extreme operating scenario. The reactive power demand per kilovolt voltage change is used to evaluate the reactive power required by the wind farm when the voltage changes and is the basis for calculating the reactive power demand. The maximum voltage change is used to evaluate the reactive power required for capacitive compensation and the reactive power required for inductive compensation in an extreme operating scenario.

[0059] In a possible implementation manner, the process of obtaining the maximum reactive power output of the fan and the minimum reactive power output of the fan is specifically processed as follows: Apply excitation current to each fan; increase the excitation current of each fan at a preset interval. When the fan issues an overexcitation limit alarm, the power at this time is determined as the maximum reactive power output of the fan; calculate the maximum reactive power output of the fan according to the maximum reactive power output of each fan; decrease the excitation current of each fan at a preset interval. When the fan issues an underexcitation limit alarm, the power at this time is determined as the minimum reactive power output of the fan; calculate the minimum reactive power output of the fan according to the minimum reactive power output of each fan.

[0060] In this embodiment, by gradually adjusting the excitation current of the fan and monitoring the alarm signal of the fan, the reactive power output range of each fan under extreme conditions is determined.

[0061] Specifically, for example, gradually increase the excitation current of the fan 1 until the fan 1 issues an "over-excitation limit alarm", and read the maximum reactive power Q of the fan wmax1 , and test the maximum reactive power Q of the fan 2, fan 3, …, fan N respectively according to this method wmax2 、Q wmax3 、…、Q wmaxN . Add up the maximum values of the reactive power output by all fans to obtain the maximum value of the reactive power output by the fans. The formula is as follows:

[0062]

[0063] In the formula, Q w max i is the maximum reactive power of the i-th fan

[0064] Gradually decrease the excitation current of the fan 1 until the fan issues an "under-excitation limit alarm", and read the minimum reactive power Q of the fan 1 wmin1 , and test the minimum reactive power Q of the fan 2, fan 3, …, fan N respectively according to this method wmin2 、Q wmin3 、…、Q wminN . Add up the minimum values of the reactive power output by all fans to obtain the minimum value of the reactive power output by the fans. The formula is as follows:

[0065]

[0066] In the formula, Q w min i is the minimum reactive power of the i-th fan

[0067] In a possible implementation, the process of obtaining the maximum value of the reactive power output by the SVG device and the minimum value of the reactive power output by the SVG device is specifically processed as follows: change the control angle of the SVG device; increase the control angle of the SVG device at a preset interval. When the SVG device issues a minimum output limit alarm, determine the power at this time as the minimum value of the reactive power output by the SVG device; decrease the control angle of the SVG device at a preset interval. When the SVG device issues a maximum output limit alarm, determine the power at this time as the maximum value of the reactive power output by the SVG device

[0068] In this embodiment, by adjusting the control angle of the SVG device and monitoring the alarm signal issued by the device, the reactive power output range of the SVG device under extreme conditions is determined

[0069] In a possible implementation, the process of obtaining the reactive power demand per kilovolt voltage change is specifically processed as follows: Obtain the current voltage value and the current reactive power value at the connection point of the AVC system; perform a step test on the voltage command value at the connection point of the AVC system to obtain the voltage value after the step test and the reactive power value after the step test; calculate the reactive power demand per kilovolt voltage change based on the current voltage value and the current reactive power value, the voltage value after the step test, and the reactive power value after the step test.

[0070] In this embodiment, the step amount in the step test is less than 4% of the connection point voltage value, and the calculation formula for the reactive power demand per kilovolt voltage change is as follows:

[0071]

[0072] In the formula, Q1 and Q2 are the current reactive power value and the reactive power value after the step test respectively, and U1 and U2 are the current voltage value and the voltage value after the step test respectively.

[0073] In a possible implementation, the process of obtaining the maximum voltage change amount is specifically processed as follows: Obtain the steady-state voltage of the bus before the fault and the minimum value of the bus voltage during the fault; calculate the maximum capacitive compensation voltage change amount based on the steady-state voltage of the bus before the fault and the minimum value of the bus voltage during the fault; obtain the upper limit of the voltage command interval at the connection point of the AVC system and the corresponding bus voltage value; calculate the maximum inductive compensation voltage change amount based on the upper limit of the voltage command interval at the connection point of the AVC system and the corresponding bus voltage value.

[0074] In this embodiment, the maximum voltage change amount refers to the change range of the bus voltage in an extreme operating scenario (such as when all new energy power such as wind power and photovoltaic power in the region is cut off). Among them, the maximum capacitive compensation voltage change amount is used to evaluate the capacitive reactive power demand, and the maximum inductive compensation voltage change amount is used to evaluate the inductive reactive power demand. The steady-state voltage of the bus before the fault refers to the normal operating value of the bus voltage before the extreme operating scenario occurs, and the voltage value of the bus in the normal operating state is obtained through simulation. The minimum value of the bus voltage during the fault refers to the lowest value to which the bus voltage drops when the extreme operating scenario occurs. The extreme operating scenario (such as when all new energy power such as wind power and photovoltaic power is cut off) is simulated through time-domain simulation, and the minimum value of the bus voltage is recorded. The upper limit of the voltage command interval at the connection point of the AVC system refers to the highest value that the AVC system allows the bus voltage to reach, and the upper limit value of the voltage command at the connection point is obtained from the AVC system. The corresponding bus voltage value refers to the bus voltage value actually measured when the voltage command at the connection point of the AVC system reaches the upper limit, and is obtained through real-time monitoring of the AVC system.

[0075] Specifically, the calculation formula for the maximum capacitive compensation voltage change amount is as follows:

[0076] ΔU = U3 - U4

[0077] Wherein, U3 is the steady-state voltage of the bus before the fault, and U4 is the minimum value of the bus voltage during the fault. The calculation formula for the maximum voltage change of inductive compensation is as follows:

[0078] ΔU' = U5 - U6

[0079] Wherein, U5 is the upper limit of the voltage command range of the AVC system connection point, and U6 is the corresponding bus voltage value.

[0080] Step 102: Calculate the capacitive reactive power reserve and the inductive reactive power reserve respectively according to the basic data of the reactive power reserve of the wind farm reactive power equipment.

[0081] In a possible implementation manner, the operating parameters of the wind farm reactive power equipment include the output power of the SVG device, the output power of the wind turbine generator set, the number of unconnected capacitors, the number of unconnected reactors, the rated reactive power of the capacitor, and the rated reactive power of the reactor;

[0082] Correspondingly, in step 102 of the present invention, the capacitive reactive power reserve and the inductive reactive power reserve are calculated respectively according to the basic data of the reactive power reserve of the wind farm reactive power equipment, and the specific processing is as follows: The capacitive reactive power reserve is calculated according to the rated reactive power of the capacitor, the number of unconnected capacitors, the minimum value of the reactive power output by the fan, the minimum value of the reactive power output by the SVG device, the output power of the wind turbine generator set, and the output power of the SVG device; The inductive reactive power reserve is calculated according to the rated reactive power of the reactor, the number of unconnected reactors, the maximum value of the reactive power output by the fan, the maximum value of the reactive power output by the SVG device, the output power of the wind turbine generator set, and the output power of the SVG device.

[0083] In this embodiment, the operating parameters of the wind farm reactive power equipment are collected, and the output power Q of the SVG device is read by the AVC system of the wind farm s 、the output power Q of the wind turbine generator set w 、the number m of unconnected capacitors, and the number n of unconnected reactors; The rated reactive power Q of the capacitor is read from the capacitor nameplate ce ,and the rated reactive power Q of the reactor is read from the reactor nameplate Le 。The maximum value Q of the reactive power output by the fan is actually measured on site wmax and the minimum value Q of the reactive power output by the fan wmin ,The maximum value Q of the reactive power output by the SVG device is actually measured on site smax and the minimum value Q of the reactive power output by the SVG device smin 。

[0084] Among them, the capacitive reactive power reserve Q c is:

[0085] Q c = Q ce × m + Q wmin + Q smin - Q w - Q s

[0086] Reactive power reserve Q L is:

[0087] Q L = Q Le × n + Q wmax + Q smax - Q w - Q s

[0088] In this embodiment, by calculating the capacitive reactive power reserve and the inductive reactive power reserve, it can be determined whether the wind farm can meet the reactive power demand of the power grid under extreme operating scenarios, thus ensuring the stable operation of the power grid voltage.

[0089] Step 103: Calculate the capacitive reactive power demand and the inductive reactive power demand respectively according to the reactive power demand per kilovolt voltage change and the maximum voltage change; wherein, the maximum voltage change includes the maximum voltage change of capacitive compensation and the maximum voltage change of inductive compensation.

[0090] In a possible implementation manner, calculating the capacitive reactive power demand and the inductive reactive power demand respectively according to the reactive power demand per kilovolt voltage change and the maximum voltage change is specifically processed as follows: calculating the capacitive reactive power demand according to the reactive power demand per kilovolt voltage change and the maximum voltage change of capacitive compensation; calculating the inductive reactive power demand according to the reactive power demand per kilovolt voltage change and the maximum voltage change of inductive compensation.

[0091] Specifically, the calculation formula of the capacitive reactive power demand is as follows:

[0092] Q c ' = ΔU × ΔQ

[0093] In the formula, ΔU is the maximum voltage change of capacitive compensation, and ΔQ is the reactive power demand per kilovolt voltage change.

[0094] The calculation formula of the inductive reactive power demand is as follows:

[0095] Q L ' = ΔU' × ΔQ

[0096] In the formula, ΔU’ is the maximum voltage change of inductive compensation, and ΔQ is the reactive power demand per kilovolt voltage change.

[0097] In this embodiment, the capacitive reactive power demand and the inductive reactive power demand reflect the reactive power required for the wind farm to maintain the stability of the bus voltage under extreme operating scenarios, which is an important basis for evaluating the reactive power reserve capacity of the wind farm.

[0098] Step 104: Obtain the reactive power reserve evaluation result of the wind farm based on the capacitive reactive power reserve, the inductive reactive power reserve, the capacitive reactive power demand, and the inductive reactive power demand.

[0099] In a possible implementation manner, obtaining the reactive power reserve evaluation result of the wind farm based on the capacitive reactive power reserve, the inductive reactive power reserve, the capacitive reactive power demand, and the inductive reactive power demand is specifically processed as follows: When the capacitive reactive power reserve is greater than or equal to the capacitive reactive power demand, the capacitive reactive power reserve during capacitive compensation of the wind farm meets the requirements of the power grid for capacitive reactive power voltage regulation; when the capacitive reactive power reserve is less than the capacitive reactive power demand, the capacitive reactive power reserve during capacitive compensation of the wind farm does not meet the requirements of the power grid for capacitive reactive power voltage regulation, and capacitive reactive compensation equipment needs to be added; when the absolute value of the inductive reactive power reserve is greater than or equal to the absolute value of the inductive reactive power demand, the inductive reactive power reserve during inductive compensation of the wind farm meets the requirements of the power grid for inductive reactive power voltage regulation; when the absolute value of the inductive reactive power reserve is less than the absolute value of the inductive reactive power demand, the inductive reactive power reserve during inductive compensation of the wind farm does not meet the requirements of the power grid for inductive reactive power voltage regulation, and inductive reactive compensation equipment needs to be added.

[0100] In this embodiment, the reactive power reserve capacity of the wind farm is evaluated based on the calculated capacitive reactive power reserve, inductive reactive power reserve, capacitive reactive power demand, and inductive reactive power demand, and it is determined whether reactive compensation equipment needs to be added accordingly.

[0101] In the embodiment of the present invention, by analyzing the operating conditions of reactive power equipment in the wind farm, calculating the capacitive reactive power reserve, inductive reactive power reserve, capacitive reactive power demand, and inductive reactive power demand of the wind farm under the extreme operating scenario where all new energy power such as wind power and photovoltaic power in the local area is cut off, and evaluating the reactive power reserve of the wind farm based on the capacitive reactive power reserve, inductive reactive power reserve, capacitive reactive power demand, and inductive reactive power demand to determine whether the reactive power reserve of the wind farm meets the requirements for rapid voltage change in extreme cases.

[0102] To better understand the present invention, the above process will be described in detail below with specific examples. The numerical values used in this example are only for illustration, and users can make corresponding changes according to actual needs.

[0103] In this embodiment, the "PSD Power System Software Tools (PSD PowerTools)" series of software packages developed by China Electric Power Research Institute are used as the simulation calculation tools for this research, mainly including: PSD-PFNT power flow calculation program, PSD-SWNT transient stability calculation program, and PSD-SSAP small-signal stability calculation program.

[0104] In this embodiment, the data of Wanhui Wind Farm is used, with an installed capacity of 96 MW and 64 1.5 MW wind turbines.

[0105] The first step is for the AVC system of the wind farm to read the output power Q of the SVG device s = 18 MVar, the output power Q of the wind turbine w = 10 MVar, 1 capacitor not put into operation, 1 reactor not put into operation. Read the rated reactive power Q of the capacitor from the capacitor nameplate ce = 6 MVar, and read the rated reactive power Q of the reactor from the reactor nameplate Le = -6 MVar.

[0106] The second step is to actually test the maximum reactive power Q output by the wind turbine on site wmax and the minimum reactive power Q output by the wind turbine wmin . To simplify the test plan, a typical unit is selected for testing, and equivalent calculations are performed on other units. Gradually increase the excitation current of wind turbine 1 until wind turbine 1 issues an "over-excitation limit alarm", and read the maximum reactive power Q of the wind turbine wmax1 = 0.4 MVar, and calculate the maximum reactive power Q output by the wind turbine wmax = 0.4 MVar × 64 units = 25.6 MVar;

[0107] Gradually decrease the excitation current of wind turbine 1 until the wind turbine issues an "under-excitation limit alarm", and read the minimum reactive power Q of wind turbine 1 wmin1 = -0.3 MVar, and calculate the minimum reactive power Q output by the wind turbine wmin = -0.3 MVar × 64 units = -19.2 MVar.

[0108] The third step is the method for actually testing the maximum reactive power Q output by the SVG device on site smax and the minimum reactive power Q output by the SVG device smin is as follows: Gradually increase the control angle of the SVG device until the SVG device issues a "minimum output limit alarm", and read the minimum output reactive power Q of the SVG device smin = -30 MVar; Gradually decrease the control angle of the SVG device until the SVG device issues a "maximum output limit alarm", and read the maximum output reactive power Q of the SVG device smax = 30 MVar.

[0109] Step 4: Calculate the reactive power reserve of the wind farm based on the above data. The capacitive reactive power reserve Q c is:

[0110] Q c = Q ce × m + Q wmin + Q smin - Q w - Q s = 6 * 1 + 30 + 25.6 - 18 - 10 = 33.6 MVar

[0111] The inductive reactive power reserve Q L is:

[0112] Q L = Q Le × n + Q wmax + Q smax - Q w - Q s = -6 * 1 - 19.2 - 30 - 18 - 10 = -83.2 MVar

[0113] Step 5: Use the method of step change of the grid connection point voltage command of the wind farm AVC system to actually test the reactive power demand per kilovolt voltage change. In the AVC system, change the grid connection point voltage command value of the wind farm, conduct a step change test of the voltage command, record the voltage values U1 = 117.07 kV, U2 = 115.92 kV and reactive power values Q1 = 37 MVar, Q2 = 16 MVar before and after the step change test of the voltage command, and calculate the reactive power demand ΔQ per kilovolt voltage change:

[0114]

[0115] Step 6: Use the time-domain simulation method to calculate the change amount of the bus voltage under the extreme operation scenario where all new energy powers such as wind power and photovoltaic power in this area are cut off. The steady-state voltage U3 = 117.17 kV of the bus before the fault and the minimum value U4 = 113.49 kV of the bus voltage during the fault process. From this, calculate the maximum capacitive compensation voltage change amount ΔU:

[0116] ΔU = U3 - U4 = 117.17 - 113.49 = 3.68 kV

[0117] Calculate the capacitive reactive power demand Q c ’ required for capacitive compensation, that is, the maximum capacitive compensation voltage change amount ΔU multiplied by the reactive power demand ΔQ per kilovolt voltage change:

[0118] Q c ' = ΔU × ΔQ = 18.26 * 3.68 = 67.20 MVar

[0119] Step 7, calculation of the maximum reactive power compensation. At a certain moment, the upper limit of the grid connection point voltage command range of the wind farm AVC system is U5 = 118 kV, and the bus voltage value U6 = 117.07 kV is read from the wind farm AVC system at this time. Then, the maximum voltage change ΔU’ for reactive power compensation is calculated as follows:

[0120] ΔU' = U6 - U5 = 117.07 - 118 = -0.93 kV

[0121] Calculate the reactive power demand Q L ’ for inductive compensation, that is, the maximum voltage change ΔU’ for inductive compensation is multiplied by the reactive power demand ΔQ per kV voltage change:

[0122] Q L ' = ΔU' × ΔQ = -0.93 * 18.26 = -16.98 MVar

[0123] Step 8, determine whether the capacitive reactive power reserve of the wind farm meets the requirements of the grid for capacitive reactive power voltage regulation.

[0124] According to the above calculation, since 33.6 > 67.20, that is, Q c < Q c ’ The capacitive reactive power reserve is less than the capacitive reactive power demand, so the capacitive reactive power reserve during capacitive compensation of the wind farm does not meet the requirements of the grid for capacitive reactive power voltage regulation.

[0125] Step 9, determine whether the inductive reactive power reserve of the wind farm meets the requirements of the grid for inductive reactive power voltage regulation.

[0126] Since |-83.2| > |-16.98|, that is, |Q L | > |Q' L | The inductive reactive power reserve is greater than the inductive reactive power demand, so the inductive reactive power reserve during inductive compensation of the wind farm meets the requirements of the grid for inductive reactive power voltage regulation.

[0127] Figure 3 It is the bus voltage curve of the Wanhui Wind Farm when all other wind farms and photovoltaic power plants in the substation where the Wanhui Wind Farm is located are cut off at the generator terminals provided in the embodiment of the present invention.

[0128] The present invention measures reactive power control parameters such as on-site measured reactive voltage proportionality coefficients, and uses software simulation to calculate the reactive power demand under extreme operating scenarios where all new energy power such as wind power and photovoltaic power in the region is cut off. By combining on-site measurements and simulation results, the reactive power demand and reactive power reserve capacity of the wind farm are calculated respectively, and its reactive power reserve capacity is evaluated to determine whether the reactive power reserve of the wind farm meets the requirements of rapid voltage change under extreme operating scenarios. If the reactive power reserve is greater than the reactive power demand under the extreme operating scenario where all new energy power such as wind power and photovoltaic power in the region is cut off, it is considered that the reactive power reserve is greater than the reactive power demand under all operating modes, and the grid voltage can maintain stable operation. This method has a simple structure and is easy to implement in engineering.

[0129] The present invention can quickly evaluate the dynamic reactive power reserve index of a wind farm, discover weak links, and thus adjust the operating state of the power system online. After the reactive power reserve evaluation and taking sufficient measures, a sufficient number of wind farms with reasonable configuration of dynamic reactive power reserve can solve the problem of insufficient voltage support or even complete voltage collapse, ensure a reasonable voltage level of the system after a fault, enable the system to recover from the fault state to the steady state as quickly as possible, ensure the stability of the bus voltage, and improve the transient stability level of the power system.

[0130] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.

[0131] The following is an apparatus embodiment of the present invention. For details not described in detail, reference can be made to the corresponding method embodiments above.

[0132] Figure 4 The structural schematic diagram of the reactive power reserve evaluation device of the wind farm under extreme scenarios provided by the embodiments of the present invention is shown. For the sake of convenience of description, only the parts related to the embodiments of the present invention are shown and are described in detail as follows:

[0133] As Figure 4 shown, the reactive power reserve evaluation device 4 of the wind farm under extreme scenarios includes:

[0134] A data acquisition module 41, configured to acquire the basic data of the reactive power reserve of the reactive power equipment of the wind farm, the reactive power demand per kilovolt voltage change, and the maximum voltage change amount; wherein, the basic data of the reactive power reserve of the reactive power equipment of the wind farm includes the operating parameters of the reactive power equipment of the wind farm, the maximum reactive power output of the fan, the minimum reactive power output of the fan, the maximum reactive power output of the SVG device, and the minimum reactive power output of the SVG device;

[0135] The reactive power reserve calculation module 42 is used to calculate the capacitive reactive power reserve and the inductive reactive power reserve respectively according to the basic data of the reactive power reserve of the reactive power equipment in the wind farm;

[0136] The reactive power demand calculation module 43 is used to calculate the capacitive reactive power demand and the inductive reactive power demand respectively according to the reactive power demand per kilovolt voltage change and the maximum voltage change; wherein, the maximum voltage change includes the maximum voltage change of capacitive compensation and the maximum voltage change of inductive compensation;

[0137] The evaluation module 44 is used to obtain the reactive power reserve evaluation result of the wind farm according to the capacitive reactive power reserve, the inductive reactive power reserve, the capacitive reactive power demand and the inductive reactive power demand.

[0138] In a possible implementation manner, the data acquisition module 41 is further used for:

[0139] Apply excitation current to each fan;

[0140] Increase the excitation current of each fan at a preset interval. When the over-excitation limit alarm is issued by the fan, determine the power at this time as the maximum output reactive power of the fan;

[0141] Calculate the maximum output reactive power of the fan according to the maximum output reactive power of each fan;

[0142] Decrease the excitation current of each fan at a preset interval. When the under-excitation limit alarm is issued by the fan, determine the power at this time as the minimum output reactive power of the fan;

[0143] Calculate the minimum output reactive power of the fan according to the minimum output reactive power of each fan.

[0144] In a possible implementation manner, the data acquisition module 41 is further used for:

[0145] Change the control angle of the SVG device;

[0146] Increase the control angle of the SVG device at a preset interval. When the minimum output limit alarm is issued by the SVG device, determine the power at this time as the minimum output reactive power of the SVG device;

[0147] Decrease the control angle of the SVG device at a preset interval. When the maximum output limit alarm is issued by the SVG device, determine the power at this time as the maximum output reactive power of the SVG device.

[0148] In a possible implementation manner, the data acquisition module 41 is further used for:

[0149] Obtain the current voltage value and the current reactive power value at the connection point of the AVC system.

[0150] Perform a step test on the grid connection point voltage command value of the AVC system to obtain the voltage value after the step test and the reactive power value after the step test;

[0151] Calculate the reactive power demand per kilovolt voltage change based on the current voltage value, the current reactive power value, the voltage value after the step test, and the reactive power value after the step test.

[0152] In a possible implementation, the data acquisition module 41 is further configured to:

[0153] Obtain the steady-state voltage of the bus before the fault and the minimum value of the bus voltage during the fault process;

[0154] Calculate the maximum capacitive compensation voltage change based on the steady-state voltage of the bus before the fault and the minimum value of the bus voltage during the fault process;

[0155] Obtain the upper limit of the grid connection point voltage command range of the AVC system and the corresponding bus voltage value;

[0156] Calculate the maximum inductive compensation voltage change based on the upper limit of the grid connection point voltage command range of the AVC system and the corresponding bus voltage value.

[0157] In a possible implementation, the operating parameters of the wind farm reactive power equipment include the output power of the SVG device, the output power of the wind turbine generator set, the number of unconnected capacitors, the number of unconnected reactors, the rated reactive power of the capacitor, and the rated reactive power of the reactor;

[0158] The reactive power reserve calculation module 42 is further configured to:

[0159] Calculate the capacitive reactive power reserve based on the rated reactive power of the capacitor, the number of unconnected capacitors, the minimum output reactive power of the fan, the minimum output reactive power of the SVG device, the output power of the wind turbine generator set, and the output power of the SVG device;

[0160] Calculate the inductive reactive power reserve based on the rated reactive power of the reactor, the number of unconnected reactors, the maximum output reactive power of the fan, the maximum output reactive power of the SVG device, the output power of the wind turbine generator set, and the output power of the SVG device.

[0161] In a possible implementation, the reactive power demand calculation module 43 is further configured to:

[0162] Calculate the capacitive reactive power demand based on the reactive power demand per kilovolt voltage change and the maximum capacitive compensation voltage change;

[0163] Calculate the inductive reactive power demand based on the reactive power demand per kilovolt voltage change and the maximum inductive compensation voltage change.

[0164] In a possible implementation, the evaluation module 44 is further configured to:

[0165] When the capacitive reactive power reserve is greater than or equal to the capacitive reactive power demand, the capacitive reactive power reserve during capacitive compensation of the wind farm meets the requirements of the grid's capacitive reactive power voltage regulation;

[0166] When the capacitive reactive power reserve is less than the capacitive reactive power demand, the capacitive reactive power reserve during capacitive compensation of the wind farm does not meet the requirements of the grid's capacitive reactive power voltage regulation, and capacitive reactive power compensation equipment needs to be added;

[0167] When the absolute value of the inductive reactive power reserve is greater than or equal to the absolute value of the inductive reactive power demand, the inductive reactive power reserve during inductive compensation of the wind farm meets the requirements of the grid's inductive reactive power voltage regulation;

[0168] When the absolute value of the inductive reactive power reserve is less than the absolute value of the inductive reactive power demand, the inductive reactive power reserve during inductive compensation of the wind farm does not meet the requirements of the grid's inductive reactive power voltage regulation, and inductive reactive power compensation equipment needs to be added.

[0169] Figure 5 It is a schematic diagram of the electronic device provided by the embodiment of the present invention. As Figure 5 shown, the electronic device 5 of this embodiment includes: a processor 50 and a memory 51. The memory 51 stores a computer program 52. When the processor 50 executes the computer program 52, the steps in the above-mentioned various method embodiments are implemented. Alternatively, when the processor 50 executes the computer program 52, the functions of each module in the above-mentioned various device embodiments are implemented.

[0170] Exemplarily, the computer program 52 can be divided into one or more modules, and the one or more modules / units are stored in the memory 51 and executed by the processor 50 to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, and the instruction segments are used to describe the execution process of the computer program 52 in the electronic device 5.

[0171] The electronic device 5 may include, but is not limited to, a processor 50 and a memory 51. Those skilled in the art can understand that Figure 5 merely examples of the electronic device 5 do not constitute a limitation to the electronic device 5, and it may include more or fewer components than shown in the figure, or combine some components, or different components. For example, the electronic device 5 may further include input / output devices, network access devices, buses, etc.

[0172] For the convenience and brevity of description, only the above division of each functional module / unit is used as an example. In actual applications, the above functions can be allocated to different functional modules / units according to needs. The above modules / units can be implemented in the form of hardware, software, or a combination of hardware and software.

[0173] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments. Without special instructions and logical conflicts, the terms and / or descriptions between different embodiments are consistent and can be mutually referred to. The technical features in different embodiments can be combined to form new embodiments according to their internal logical relationships.

[0174] The above-described embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included in the protection scope of the present invention.

Claims

1. A method for evaluating reactive power reserve of a wind farm under extreme scenarios, characterized in that: include: Obtain the basic data of reactive power reserve of wind farm reactive equipment, reactive power demand per kilovolt voltage change and maximum voltage change; wherein, the basic data of reactive power reserve of wind farm reactive equipment includes operating parameters of wind farm reactive equipment, maximum reactive power output of wind turbine, minimum reactive power output of wind turbine, maximum reactive power output of SVG device and minimum reactive power output of SVG device; calculate capacitive reactive power reserve and inductive reactive power reserve respectively according to the basic data of reactive power reserve of wind farm reactive equipment; calculate capacitive reactive power demand and inductive reactive power demand respectively according to reactive power demand per kilovolt voltage change and maximum voltage change; maximum voltage change includes maximum voltage change of capacitive compensation and maximum voltage change of inductive compensation; obtain reactive power reserve assessment result of wind farm according to capacitive reactive power reserve, inductive reactive power reserve, capacitive reactive power demand and inductive reactive power demand.

2. The method for evaluating reactive power reserve of a wind farm under extreme scenarios according to claim 1 is characterized in that: The operating parameters of the wind farm reactive equipment include the output power of the SVG device, the output power of the wind turbine set, the number of capacitors not put into use, the number of reactors not put into use, the rated reactive power of the capacitors, and the rated reactive power of the reactors; The method of calculating the capacitive reactive power reserve and the inductive reactive power reserve respectively according to the reactive power reserve basic data of the wind farm reactive equipment includes: The capacitive reactive power reserve is calculated according to the rated reactive power of the capacitor, the number of the unused capacitors, the minimum reactive power output of the wind turbine, the minimum reactive power output of the SVG device, the output power of the wind turbine set and the output power of the SVG device; The inductive reactive power reserve is calculated according to the rated reactive power of the reactor, the number of the unused reactors, the maximum reactive power output of the wind turbine, the maximum reactive power output of the SVG device, the output power of the wind turbine set and the output power of the SVG device.

3. The method for evaluating reactive power reserve of a wind farm under extreme scenarios according to claim 1 is characterized in that: The process of obtaining the maximum value of the wind turbine output reactive power and the minimum value of the wind turbine output reactive power includes: Applying excitation current to each fan; The excitation current of each fan is increased at a preset interval. When the fan issues an overexcitation limit alarm, the power at this time is determined as the maximum output reactive power of the fan. The maximum value of the wind turbine output reactive power is calculated according to the maximum value of the output reactive power of each wind turbine; The excitation current of each fan is reduced at a preset interval. When the fan issues an under-excitation limit alarm, the power at this time is determined as the minimum output reactive power of the fan; The minimum value of the wind turbine output reactive power is calculated based on the minimum value of the output reactive power of each wind turbine.

4. The method for evaluating reactive power reserve of a wind farm under extreme scenarios according to claim 1 is characterized in that: The process of obtaining the maximum value of the reactive power output by the SVG device and the minimum value of the reactive power output by the SVG device includes: Change the control angle for SVG devices; increasing the control angle of the SVG device at a preset interval, and when the SVG device issues a minimum output limit alarm, determining the power at this time as the minimum value of reactive power output by the SVG device; The control angle of the SVG device is reduced according to a preset interval, and when the SVG device issues a maximum output limit alarm, the power at this time is determined as the maximum reactive power output by the SVG device.

5. The method for evaluating reactive power reserve of a wind farm under extreme scenarios according to claim 1 is characterized in that: The process of obtaining the reactive power demand per kilovolt voltage change includes: Get the current voltage value and current reactive power value of the AVC system grid connection point; Perform a step test on the voltage command value of the AVC system grid connection point to obtain a voltage value after the step test and a reactive power value after the step test; The reactive power demand per kilovolt voltage change is calculated based on the current voltage value and the current reactive power value, the voltage value after the step test, and the reactive power value after the step test.

6. The method for evaluating reactive power reserve of a wind farm under extreme scenarios according to claim 5 is characterized in that: The process of obtaining the maximum voltage variation includes: Obtain the steady-state voltage of the bus before the fault and the minimum value of the bus voltage during the fault process; The maximum voltage variation of the capacitive compensation is calculated according to the steady-state voltage of the bus before the fault and the minimum value of the bus voltage during the fault process; Obtain the upper limit of the voltage command range of the AVC system grid connection point and the corresponding bus voltage value; The maximum voltage variation of the inductive compensation is calculated according to the upper limit of the voltage command interval of the AVC system grid connection point and the corresponding bus voltage value.

7. The method for evaluating reactive power reserve of a wind farm under extreme scenarios according to claim 6 is characterized in that: The method of calculating the capacitive reactive power demand and the inductive reactive power demand respectively according to the reactive power demand per kilovolt voltage change and the maximum voltage change includes: Calculating the capacitive reactive power demand according to the reactive power demand per kilovolt voltage change and the capacitive compensation maximum voltage change; The inductive reactive power demand is calculated according to the reactive power demand per kilovolt voltage change and the maximum voltage change of inductive compensation.

8. The method for evaluating reactive power reserve of a wind farm under extreme scenarios according to claim 7 is characterized in that: The reactive power reserve evaluation result of the wind farm is obtained according to the capacitive reactive power reserve, the inductive reactive power reserve, the capacitive reactive power demand and the inductive reactive power demand, including: When the capacitive reactive power reserve is greater than or equal to the capacitive reactive power demand, the capacitive reactive power reserve during capacitive compensation of the wind farm meets the requirements of capacitive reactive voltage regulation of the power grid; When the capacitive reactive power reserve is less than the capacitive reactive power demand, the capacitive reactive power reserve during capacitive compensation of the wind farm does not meet the requirements of capacitive reactive voltage regulation of the power grid, and capacitive reactive compensation equipment needs to be added; When the absolute value of the inductive reactive power reserve is greater than or equal to the absolute value of the inductive reactive power demand, the inductive reactive power reserve during inductive compensation of the wind farm meets the requirements of inductive reactive voltage regulation of the power grid; When the absolute value of the inductive reactive power reserve is smaller than the absolute value of the inductive reactive power demand, the inductive reactive power reserve during inductive compensation of the wind farm does not meet the requirements of inductive reactive voltage regulation of the power grid, and inductive reactive compensation equipment needs to be added.

9. A wind farm reactive power reserve assessment device under extreme scenarios, characterized in that: include: A data acquisition module is used to obtain basic reactive power reserve data of reactive equipment in a wind farm, reactive power demand per kilovolt voltage change, and maximum voltage change; wherein the basic reactive power reserve data of reactive equipment in a wind farm includes operating parameters of reactive equipment in the wind farm, maximum reactive power output of wind turbines, minimum reactive power output of wind turbines, maximum reactive power output of SVG devices, and minimum reactive power output of SVG devices; A reactive power reserve calculation module, used to calculate the capacitive reactive power reserve and the inductive reactive power reserve respectively according to the reactive power reserve basic data of the wind farm reactive equipment; A reactive power demand calculation module, used to calculate the capacitive reactive power demand and the inductive reactive power demand according to the reactive power demand per kilovolt voltage change and the maximum voltage change; wherein the maximum voltage change includes the capacitive compensation maximum voltage change and the inductive compensation maximum voltage change; An evaluation module is used to obtain a reactive power reserve evaluation result of a wind farm according to the capacitive reactive power reserve, the inductive reactive power reserve, the capacitive reactive power demand and the inductive reactive power demand.

10. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the method according to any one of claims 1 to 8 when executing the computer program.

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