Wind farm reactive power coordination method and device and storage medium

Abstract

The application provides a wind farm reactive power coordination method, device and storage medium, relates to the field of power systems and automatic technology, and first monitors the reactive power output and maximum reactive power output capacity of each wind turbine in real time, synchronously obtains the current voltage drop amount and actual reactive power output power of a static var compensator (SVC); then calculates the reactive power margin of each wind turbine, and determines the total reactive power compensation demand of the system according to the voltage drop amount and equivalent reactance of the power grid, so that the SVC undertakes the initial compensation task; subsequently, the remaining compensation amount is distributed to each wind turbine according to the proportion of the wind turbine reactive power margin, the adjustment instruction is generated by limiting the superposition current output to be not more than the maximum capacity; if the certain wind turbine still exceeds the limit after adjustment, the excess part is redistributed to other wind turbines with margin, until all wind turbines operate within the safe range; finally, the SVC output and power grid state change are tracked in real time, the compensation distribution is dynamically optimized, and the balance of the reactive power coordination is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power systems and its automation technology, in particular to a wind farm reactive power coordination method, device and storage medium. BACKGROUND

[0002] The wind power system generally adopts the detection and off-grid strategy for the fault wind turbine, and causes regional voltage collapse. The light fault wind turbine still has partial power generation capacity, and most of the faults are temporary or non-structural faults. When the blade cracks, the generator winding short circuit and other situations occur, the wind turbine will be forced to off-grid. Therefore, the non-serious fault wind turbine of the wind farm needs to adopt the strategy of running with reduced capacity with faults. At this time, when the reactive power supply and demand in the power grid is unbalanced, the voltage will deviate from the rated value, and in severe cases, it may cause voltage collapse or equipment damage. Especially when the power grid fails or the load suddenly changes, the wind farm needs to quickly respond to voltage drop and inject reactive power to maintain voltage stability.

[0003] The traditional reactive power compensation scheme mainly relies on static var compensation device (SVC), which has fast response speed (millisecond level), but has the following limitations. The rated capacity of SVC is fixed, and it may not be able to meet all the reactive power demand in the case of serious voltage drop. Long-term full-load operation will accelerate the wear of the core components such as SVC thyristor, shortening the service life. High-capacity SVC devices, such as high-capacity STATCOM static synchronous compensator, are expensive, and there are still some limitations on short-term high-capacity reactive power support. The potential of wind turbine's own reactive power regulation is not fully utilized. When the power grid demand changes or the SVC (static var compensation device) cannot meet the demand due to capacity limitations, the traditional control strategy cannot adjust the wind turbine compensation task in real time, resulting in delayed voltage recovery or oscillation, affecting the stability of the power grid. Modern double-fed induction wind turbines (DFIG) and full-power converter wind turbines (PMSG) have certain reactive power regulation capabilities and can provide partial reactive power compensation by adjusting the power factor (PF) or reactive power command. However, the reactive power capacity of wind turbines is limited, and they usually prioritize active output. Therefore, in extreme conditions, they cannot fully meet the power grid's reactive power demand. Therefore, there is a need for a method of joint reactive power regulation of SVC and wind turbines to effectively improve the reactive power support capability of wind farms, reduce voltage fluctuations, allow fault wind turbines to continue running with limited reactive power output, avoid complete power outage affecting the stability of the power grid, and improve the reliability and safety of wind power grid connection.

[0004] The above information disclosed in the BACKGROUND section is only used to enhance the understanding of the background of the present disclosure, and therefore it can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0005] The purpose of the present application is to provide a wind farm reactive power coordination method and device to solve the problems raised in the background.

[0006] To achieve the above object, the present application provides the following technical solutions.

[0007] The wind farm reactive power coordination method comprises the following specific steps:

[0008] Step 1: Real-time acquisition of bus voltage and wind farm grid-connected point voltage to calculate voltage drop amount, and limitation of active output of non-fault wind turbine when the voltage drop amount exceeds the set voltage drop amount threshold value;

[0009] Step 2: Calculation of reactive power margin based on the current reactive power output and the maximum reactive power output capacity of each wind turbine, calculation of required reactive power compensation amount based on the voltage drop amount, the equivalent reactance of the grid-connected point and the maximum reactive power output capacity of the SVC, and calculation of reactive power distribution coefficient based on the total number of wind turbines and the reactive power margin of each wind turbine;

[0010] Step 3: Pre-setting of SVC reactive power compensation coefficient, and calculation of initial compensation amount of the SVC based on the SVC reactive power compensation coefficient and the voltage drop amount;

[0011] Step 4: Calculation of wind turbine reactive power compensation amount by using the initial compensation amount of the SVC and the required reactive power compensation amount, calculation of adjusted reactive power output of each wind turbine by using the wind turbine reactive power adjustment amount, the reactive power distribution coefficient and the wind turbine reactive power compensation amount, and iterative optimization of the reactive power distribution

[0012] Further, the method for real-time acquisition of bus voltage and wind farm grid-connected point voltage to calculate voltage drop amount is as follows:

[0013] Real-time acquisition of wind farm bus voltage and wind farm grid-connected point voltage to calculate voltage drop amount:

[0014]

[0015] In the formula, Uref represents the rated voltage of the wind farm, Ubus represents the bus voltage of the wind farm, Ugrid represents the grid-connected end voltage of the wind farm, ΔU represents the voltage drop amount.

[0016] Further, the method for limiting the active output of the non-fault wind turbine when the voltage drop amount exceeds the set voltage drop amount threshold value is as follows:

[0017] First, set the voltage drop threshold value:

[0018]

[0019] In the formula, Kref represents the rated coefficient, ΔUth represents the voltage drop threshold value, wherein, When ΔU > Kref * ΔUth, If the duration exceeds 50ms, a voltage drop fault is determined to have occurred.

[0020] The faulty fan was located using the short-circuit current detection method. The output current of a specific fan was set to... ,in This represents the index of the wind turbines in the wind farm. This indicates the total number of wind turbines, and the short-circuit current threshold is set to... ,when At that time, determine the fan A malfunction occurred;

[0021] Limit the active power output of non-faulty wind turbines and calculate the adjustment factor:

[0022]

[0023] In the formula, Indicates the adjustment factor. This represents the minimum constraint threshold, and ;

[0024] Limit the active power output of non-faulty wind turbines:

[0025]

[0026] In the formula, This represents the active power output of each non-faulty wind turbine. This indicates a limitation on the active power output of non-faulty wind turbines.

[0027] Furthermore, the method for calculating the reactive power margin, the required reactive power compensation, and the reactive power distribution factor is as follows:

[0028] Calculate the reactive power margin using the current reactive power output of each wind turbine and the maximum reactive power output capacity of each wind turbine:

[0029]

[0030] In the formula, Indicates the first The maximum reactive power output capacity of a typhoon turbine. Indicates the first The reactive power output of the typhoon generator Indicates the first The reactive power margin of a typhoon fan is the additional reactive power it can provide. At the same time, the reactive power margin of a faulty fan is set to 0.

[0031] Record the equivalent reactance of the grid connection point, the maximum reactive power compensation capacity of the SVC, and calculate the required reactive power compensation:

[0032]

[0033] In the formula, Represents the equivalent reactance at the grid connection point. This indicates the maximum reactive power compensation capacity of the SVC. Indicates the required reactive power compensation;

[0034] Finally, the reactive power distribution factor is calculated based on the total number of wind turbines and the reactive power margin of each turbine:

[0035]

[0036] In the formula, This represents the sum of the reactive power margins of all wind turbines. Indicates the first The reactive power margin of typhoon turbines Indicates the first The reactive power distribution factor of a typhoon generator.

[0037] Furthermore, the method for calculating the reactive power adjustment of the wind turbines based on the current reactive power output of the SVC, the required reactive power compensation, and the current reactive power output of each wind turbine is as follows:

[0038] Extract the current reactive power output of the SVC, the required reactive power compensation, and calculate the overall reactive power adjustment of the wind turbine:

[0039]

[0040] In the formula, This indicates the required reactive power compensation. This indicates the current reactive power output of the SVC. This indicates the overall reactive power adjustment of the wind turbines, which is the amount of reactive power compensation that the wind turbines in the wind farm need to bear.

[0041] Then, calculate the first... Typhoon generator reactive power adjustment:

[0042]

[0043] In the formula, Indicates the first Typhoon generator reactive power adjustment, i.e., the first The reactive power of the typhoon generator needs to be adjusted.

[0044] Furthermore, the method for calculating the reactive power compensation of the wind turbine using the initial SVC compensation and the required reactive power compensation is as follows:

[0045] Pre-set SVC reactive power compensation coefficient ,and Extract voltage drop Calculate the initial compensation amount for SVC:

[0046]

[0047] wherein, represents the SVC initial compensation amount;

[0048] extracting the SVC initial compensation amount and the required reactive compensation amount , calculating the wind turbine reactive compensation amount:

[0049]

[0050] wherein, represents the required reactive compensation amount, represents the wind turbine reactive compensation amount, i.e. the additional reactive compensation amount required by the wind turbine of the wind farm.

[0051] Further, the method for calculating the adjusted reactive output of each wind turbine using the reactive distribution coefficient and the wind turbine reactive compensation amount is:

[0052] calculating the reactive supplement amount of each wind turbine:

[0053]

[0054] wherein, represents the reactive supplement amount required by the th wind turbine to be adjusted;

[0055] then the adjusted reactive output of the th wind turbine is:

[0056]

[0057] wherein, represents the adjusted reactive output of the th wind turbine, i.e. the adjusted reactive output of the th wind turbine.

[0058] Further, the method for iteratively optimizing the reactive distribution is:

[0059] monitoring the adjusted reactive output of the th wind turbine and the maximum reactive output capacity of the th wind turbine , when , it is determined that the th wind turbine reaches the upper limit of the reactive output, and other wind turbines are determined to be wind turbines with adjustment space, and the reactive output is redistributed:

[0060] First, calculate the reactive amount exceeding the maximum output:

[0061]

[0062] wherein, represents the reactive power of the wind turbine exceeding the maximum output;

[0063] calculate the new total reactive power margin of the wind turbines:

[0064]

[0065] wherein, represents the set of wind turbines still having adjustment space, represents the new total reactive power margin of the wind turbines, represents the reactive power margin of the wind turbine;

[0066] recalculate the reactive power distribution factor:

[0067]

[0068] wherein, represents the new reactive power distribution factor of the wind turbine;

[0069] finally, redistribute the reactive power exceeding the maximum output:

[0070]

[0071] wherein, represents the reactive power of the wind turbine exceeding its maximum reactive power output capability, represents the reactive power of the wind turbine exceeding the upper limit that needs to be adjusted, i.e. the new reactive power supplement that needs to be adjusted, wherein, represents the number of wind turbines exceeding the maximum reactive power output capability, represents the total number of wind turbines exceeding the maximum reactive power output capability;

[0072] finally, calculate the adjusted reactive power output of the wind turbine as:

[0073]

[0074] wherein, represents the adjusted reactive power output of the wind turbine;

[0075] If there are still wind turbines exceeding their maximum reactive power output capability, repeat all the steps from the beginning of the monitoring until the reactive power output of all wind turbines does not exceed their maximum reactive power output capability.

[0076] The application further provides a reactive power coordination device for a wind farm, which is used to perform the above-mentioned reactive power coordination method of the wind farm, comprising:

[0077] a voltage drop monitoring module for collecting bus voltage and wind farm grid-connected point voltage in real time to calculate voltage drop amount, limiting active output of non-fault wind turbine when voltage drop amount exceeds set voltage drop amount threshold;

[0078] a reactive power margin distribution module for calculating reactive power margin based on current reactive output of each wind turbine and maximum reactive output capacity, calculating required reactive compensation amount based on voltage drop amount, grid-connected point equivalent reactance and maximum reactive output capacity of SVC, and calculating reactive distribution coefficient based on total number of wind turbines and reactive power margin of each wind turbine;

[0079] a cooperative compensation calculation module for calculating wind turbine reactive adjustment amount based on current output of SVC, required reactive compensation amount and current reactive output of each wind turbine, pre-setting SVC reactive compensation coefficient, and calculating initial compensation amount of SVC based on SVC reactive compensation coefficient and voltage drop amount;

[0080] a dynamic adjustment iteration module for calculating wind turbine reactive compensation amount through initial compensation amount of SVC and required reactive compensation amount, calculating adjusted reactive output of each wind turbine by using reactive distribution coefficient and wind turbine reactive compensation amount, and iteratively optimizing reactive distribution.

[0081] The application further provides a storage medium having a computer program stored therein, wherein the computer program is executed by a processor to implement the wind farm reactive coordination method.

[0082] Compared with the prior art, the application has the following beneficial effects:

[0083] By monitoring bus and grid-connected point voltage in real time, voltage drop is quickly identified and active limitation is triggered to provide resource guarantee for subsequent reactive output, then reactive distribution coefficient is dynamically calculated based on wind turbine reactive margin, i.e. difference between current output and maximum capacity, to ensure that wind turbines with large reactive margin undertake more tasks, avoid local overload, reduce risk of long-term full-load operation of SVC, and iteratively optimize reactive distribution in real time to further ensure that wind turbine reactive output is always within a safe range. BRIEF DESCRIPTION OF DRAWINGS

[0084] Figure 1 It is a schematic diagram of the overall method of the application;

[0085] Figure 2 It is a wind turbine reactive distribution coefficient diagram of the application;

[0086] Figure 3 It is a wind turbine reactive power adjustment diagram before and after adjustment of the application;

[0087] Figure 4 It is a wind turbine over-limit redistribution change diagram of the application;

[0088] Figure 5 The whole device module schematic diagram of the present application. DETAILED DESCRIPTION

[0089] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with specific examples.

[0090] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the general meaning understood by those skilled in the art to which the present application belongs. The "first", "second" and similar words used in the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Include" or "contain" and similar words mean that the elements or objects before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connected" or "connected" and similar words are not limited to physical or mechanical connection, but can include electrical connection, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to represent relative positional relationship, when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0091] Embodiment:

[0092] Please refer to Figures 1 to 4 The present application provides a technical solution:

[0093] The wind farm reactive power coordination method, the specific steps include:

[0094] Step 1: Real-time acquisition of bus voltage and wind farm grid-connected point voltage to calculate voltage drop amount, when the voltage drop amount exceeds the set voltage drop amount threshold, the active output of non-fault wind turbine is limited;

[0095] High-precision voltage sensors are installed at the wind farm bus and the grid-connected point, i.e. the outlet of the booster station, to real-time collect the wind farm bus voltage and the wind farm grid-connected point voltage, and calculate the voltage drop amount:

[0096]

[0097] In the formula, U represents the rated voltage of the wind farm, U represents the wind farm bus voltage, U represents the wind farm grid-connected point voltage, U represents the voltage drop amount, and the minimum value of the bus and grid-connected point voltage is taken, in order to ensure that the most serious voltage drop situation is captured, since temporary fluctuations or abnormal faults, This item may have outliers, while transient processes of short voltage fluctuations usually decay within 1 to 3 power frequency cycles, according to industry experience, voltage drop of 10% for 50ms can effectively distinguish short voltage fluctuations and persistent fault conditions, therefore, when or the continuous time is less than 50ms, the value is not recorded, excluding accidental fluctuations. Value, excluding accidental fluctuations.

[0098] Set the voltage drop threshold:

[0099]

[0100] In the formula, represents the rated coefficient, i.e. the maximum voltage drop ratio allowed, represents the voltage drop threshold, which is dynamically adjusted according to the grid strength, when the grid strength is stronger, representing the larger short-circuit capacity, the stronger the voltage support ability, the voltage drop threshold allowed can be appropriately relaxed; otherwise, the weak grid needs to set a more stringent threshold to trigger protection action quickly, wherein, , the default setting is , i.e. 10% of the rated voltage drop, which meets the monitoring threshold of power system voltage sag regulation, when the internal power electronic equipment of the wind turbine, such as converter, capacitor, is damaged due to overcurrent or overheating, it will cause voltage drop, therefore, when and the duration exceeds 50ms, it is determined that voltage drop fault occurs;

[0101] To ensure response speed and reliability, short-circuit current detection method is used to locate the fault wind turbine, and the output current of a wind turbine is set as , wherein , represents the index of wind turbine in the wind farm, represents the total number of wind turbines, and the short-circuit current threshold is set as When , it is determined that the wind turbine fails;

[0102] Limiting the active output of non-fault wind turbines, i.e. reducing the active power absorbed by the wind turbine from the grid, can alleviate the power shortage of the grid and reduce the risk of further voltage drop, first calculate the adjustment factor:

[0103]

[0104] In the formula, represents the adjustment factor, represents the minimum constraint threshold, and , The value of the active power output limit of the non-fault wind turbine is set according to the technical parameters provided by the wind turbine manufacturer and the actual operation constraints, such as the minimum active power output ratio specified in the technical manual of the wind turbine manufacturer, which is not less than 70% of the rated value, i.e. , which can ensure that the wind turbine remains in a relatively stable operating state under active power limitation, avoiding damage to the wind turbine equipment due to excessively low active power output. If the voltage drop is small, , the value of the active power output of the non-fault wind turbine after limitation will be close to the current active power output of the non-fault wind turbine, ensuring that the wind farm can still have a high active power output when the fault is light, maintaining a certain power generation efficiency; if the voltage drop is large, , the value of the active power output of the non-fault wind turbine after limitation will be far from 1, and a severe voltage drop will lead to a sharp increase in the reactive power demand of the power grid. By reducing the active power output of the wind turbine, more capacity can be released for reactive power output, helping the power grid recover voltage stability.

[0105] Limiting the active power output of the non-fault wind turbine:

[0106]

[0107] In the formula, , represents the active power output of the current th non-fault wind turbine, , represents the active power output of the non-fault wind turbine, which is limited. This is because if the active power output is limited too low, it may lead to unstable operation of the wind turbine, such as increased vibration of the wind turbine blades, difficulty in controlling the pitch system, and even cause the wind turbine to be disconnected from the grid.

[0108] Step 2: Calculate the reactive power margin based on the current reactive power output of each wind turbine and the maximum reactive power output capacity, calculate the required reactive power compensation based on the voltage drop, the equivalent reactance of the grid connection point, and the maximum reactive power output capacity of the SVC, and calculate the reactive power distribution coefficient based on the total number of wind turbines and the reactive power margin of each wind turbine.

[0109] Through the monitoring system of the wind farm, such as the SCADA system, the reactive power output of each wind turbine is collected in real time. This system continuously monitors the electrical parameters of the wind turbine and records and transmits the reactive power data at a certain sampling frequency, such as once per second. The maximum reactive power output capacity of each wind turbine is usually provided by the wind turbine manufacturer, such as the technical manual or product specification of the equipment.

[0110] The reactive power margin is calculated using the current reactive power output of each wind turbine and the maximum reactive power output capacity of each wind turbine:

[0111]

[0112] In the formula, , represents the reactive power output of the current The maximum reactive power output capability of the typhoon machine, The first The reactive power output of the typhoon machine, The first The reactive power margin of the typhoon machine, that is, the additional reactive power that can be provided, while the reactive power margin of the faulty typhoon machine is set to 0, so that the reactive power output of the faulty typhoon machine does not undergo additional adjustment, and the compensation task is undertaken by the SVC and the non-faulty typhoon machine, and the reactive power output state of different typhoon machines is different under different operating conditions. By calculating the reactive power margin, it can be directly understood how much additional reactive power each typhoon machine can currently provide;

[0113] Record the equivalent reactance of the grid connection point , which can be obtained by grid short-circuit titration:

[0114]

[0115] In the formula, The short-circuit capacity of the grid connection point, and the short-circuit capacity of the grid connection point can be obtained from the design data of the substation, the technical manual of the equipment, the operation manual of the power system and other related technical data. When the voltage drops, the grid needs to inject reactive power to support the voltage, and the required reactive compensation is inversely proportional to the equivalent reactance of the grid connection point ;

[0116] Extract the maximum reactive compensation capacity of the SVC, and calculate the required reactive compensation:

[0117]

[0118] In the formula, The equivalent reactance of the grid connection point, The maximum reactive compensation capacity of the SVC, The required reactive compensation, when the voltage of the power system drops, the reactive power needs to be injected quickly by the reactive power compensation device such as the SVC to support the voltage. According to the relationship between the voltage drop and the equivalent reactance, This item represents the required reactive power for theoretically restoring the voltage, and the maximum reactive compensation capacity of the SVC is the physical limit of the device itself. By taking the minimum value of the theoretical value and the device capacity, it is ensured that the compensation scheme meets the voltage support requirements and does not exceed the safe range of the device.

[0119] Finally, based on the total number of typhoon machines and the reactive power margin of each typhoon machine, the reactive power distribution coefficient is calculated:

[0120]

[0121] In the formula, The sum of the reactive power margins of all typhoon machines, indicates the first The reactive power margin of the typhoon machine, indicates the first The reactive power distribution coefficient of the typhoon machine, so that the proportional distribution can ensure that each typhoon machine undertakes the reactive power compensation task according to its own remaining capacity, avoiding the overload of part of the typhoon machine while other typhoon machines still have excessive reactive power margin. Table 1 shows a data statistical table of the parameters of 40 typhoon machines and the reactive power distribution coefficient, in which there are 3 fault typhoon machines, and the fault typhoon machines do not participate in the distribution because the margin is 0.

[0122]

[0123] Table 1 Reactive power margin statistical table

[0124] As Figure 2 shown, when the typhoon machines numbered 10, 20 and 30 are faulty, the reactive power margin and the reactive power distribution coefficient of each typhoon machine change with the typhoon number. The reactive power margin is represented by black dots, and the reactive power distribution coefficient is represented by red dots. It can be seen that the reactive power margin of most typhoon machines fluctuates between 0.4-0.5 Mvar, showing a relatively regular fluctuation. The faulty typhoon machines do not participate in the logic of reactive power distribution, so the reactive power margin drops to 0, making the reactive power distribution coefficient also 0, which has the significance of reasonably distributing reactive power and improving the stability and power quality of the power system.

[0125] Step 3: Pre-set the SVC reactive power compensation coefficient, calculate the initial compensation amount of SVC based on the SVC reactive power compensation coefficient and the voltage drop amount;

[0126] Pre-set the SVC reactive power compensation coefficient , and In this interval, it can prevent insufficient compensation due to too small coefficient, which cannot effectively support the voltage, and also avoid the phenomenon of SVC output exceeding its rated capacity or causing voltage to rise too fast due to too large coefficient. By adjusting the SVC reactive power compensation coefficient , the compensation demand of different scenarios can be flexibly matched;

[0127] Extract the voltage drop amount , calculate the initial compensation amount of SVC:

[0128]

[0129] In the formula, indicates the initial compensation amount of SVC, which is the fast response value at the initial stage of fault. When the SVC detects voltage drop, it preferentially provides basic reactive power to prevent voltage from further deteriorating;

[0130] Extract the initial compensation amount of SVC and the required reactive power compensation amount , the fan reactive power compensation amount is calculated:

[0131]

[0132] In the formula, represents the required reactive power compensation amount, represents the fan reactive power compensation amount, i.e. the additional reactive power compensation amount required by the wind turbine of the wind farm, represents the remaining reactive power compensation amount that the wind farm needs to supplement through the wind turbine if the initial compensation amount of the SVC is insufficient to meet the required reactive power compensation amount The wind farm needs to supplement the remaining reactive power compensation amount through the wind turbine to achieve the purpose of fast response and accurate adjustment.

[0133] Step 4: Calculate the fan reactive power compensation amount through the initial compensation amount of the SVC and the required reactive power compensation amount, calculate the adjusted reactive power output of each wind turbine using the reactive power distribution coefficient and the fan reactive power compensation amount, and iteratively optimize the reactive power distribution;

[0134] Calculate the reactive power supplement amount of each wind turbine:

[0135]

[0136] In the formula, represents the reactive power supplement amount of the i-th wind turbine, which is proportionally distributed to each wind turbine according to the remaining reactive power margin of the wind turbine itself to avoid overloading of a single wind turbine; The adjusted reactive power output of the i-th wind turbine is:

[0137]

[0138]

[0139] In the formula, represents the adjusted reactive power output of the i-th wind turbine, i.e. the adjusted reactive power output of the i-th wind turbine, and the maximum reactive power output capability of the i-th wind turbine which ensures that the wind turbine can provide reactive power within a safe range and further avoids overloading of the wind turbine.

[0140] Table 2 shows that after calculating the reactive power margin based on the maximum reactive power output capability and the current reactive power, the reactive power distribution coefficient is calculated based on the total number of wind turbines and the reactive power margin of each wind turbine through the above formula, and thus the reactive power adjustment amount and the adjusted reactive power of each wind turbine are obtained.

[0141]

[0142] Table 2 Wind Turbine Reactive Power Adjustment Statistics ​​​​​

[0143] like Figure 3 As shown, the reactive power of each wind turbine before adjustment, the amount of reactive power adjustment, and the reactive power after adjustment are all consistent. Except for the faulty wind turbine, whose reactive power remained constant before and after adjustment, the reactive power of the non-faulty wind turbines increased to varying degrees. This aligns with the concept that a fault may cause system voltage fluctuations, requiring more reactive power to support them. Figure 3 It can be intuitively seen that the reactive power of the non-faulty wind turbines after adjustment does not exceed their maximum reactive power output capacity, leaving a safe reactive power margin. This avoids the situation where a single wind turbine is overloaded and works with the SVC to supplement reactive power, thus making balanced use of the overall reactive power resources.

[0144] At the same time, real-time monitoring of the first The reactive power output after the typhoon was adjusted With the Maximum reactive power output of typhoon turbines The comparison results, when At that time, the judgment of the first The typhoon turbines reached their reactive power output limit because, during the initial reactive power allocation based on the reactive power distribution coefficient, the maximum reactive power output capacity of each turbine was not immediately limited. Therefore, during reactive power compensation, the reactive power output of the turbines must be limited by their maximum reactive power output capacity. If the value exceeds this, it means that further compensation is not possible. At this point, the remaining reactive power demand needs to be reallocated to other wind turbines with reactive power margins to ensure the achievement of the overall compensation target.

[0145] The other wind turbines were identified as turbines with room for adjustment, and the reactive power output was redistributed:

[0146] First, calculate the reactive power exceeding the maximum output:

[0147]

[0148] In the formula, Indicates the first The typhoon generator is exceeding its maximum reactive power output;

[0149] Calculate the total reactive power margin of the new wind turbine:

[0150]

[0151] In the formula, This indicates a collection of wind turbines that still has room for adjustment. This indicates the total reactive power margin of the new wind turbine. Indicates the first The reactive power margin of typhoon turbines means that turbines with adjustment space still have the ability to undertake additional reactive power compensation tasks, while the new total reactive power margin of turbines reflects the remaining available reactive power regulation resources.

[0152] Recalculate the reactive power distribution coefficient:

[0153]

[0154] wherein, indicates the new No. The reactive power distribution coefficient of the wind turbine is the proportion of its own reactive power margin in the total reactive power margin of the new wind turbine, which ensures fair and efficient distribution, so that the wind turbine with more reactive power margin undertakes more tasks and avoids local overload;

[0155] Finally, redistribute the excess reactive power:

[0156]

[0157] wherein, indicates the No. The reactive power of the wind turbine that exceeds its maximum reactive power output capacity, indicates the No. The wind turbine that needs to adjust the reactive power that exceeds the upper limit, i.e. the new reactive power supplement amount that needs to be adjusted, wherein, , indicates the number of wind turbines that exceed the maximum reactive power output capacity, indicates the total number of wind turbines that exceed the maximum reactive power output capacity;

[0158] Finally, calculate the adjusted reactive power output of the new No.

[0159]

[0160] wherein, indicates the adjusted reactive power output of the new No.

[0161] Check the new adjusted reactive power output of all wind turbines When there are still wind turbines greater than their maximum reactive power output capacity, repeat all the steps from the beginning until the reactive power output of all wind turbines does not exceed their maximum reactive power output capacity. Because the total margin is limited, the number of iterations is limited and converges. Table 3 shows that when the reactive power is first distributed based on the reactive power distribution coefficient, the wind turbine reaches the upper limit of the reactive power output and cannot meet the adjusted reactive power output calculated directly. It needs to be finally adjusted to the reactive power amount of its maximum output, and the excess reactive power is redistributed. After summarizing, a data table is generated.

[0162]

[0163] Table 3 Reactive power over-limit redistribution table

[0164] As​​Figure 4 As shown, the number 10, 20, 30 fan fails, the initial adjustment amount is 0, in the non-fault fan, the fan adjustment amount with a margin of 0.5Mvar is 0.502Mvar, the fan adjustment amount with a margin of 0.45Mvar is 0.452Mvar, and 25 fans are adjusted to the upper limit after the reactive power, for example, the number 1 fan initial adjustment reactive power is 0.802Mvar, higher than its maximum reactive power output capacity, the reactive power reaches its maximum reactive power output capacity after re-distribution, and the remaining reactive power demand is re-distributed through multiple iterations, and finally the maximum possible reactive power compensation within the fan safety range is realized, and the fan converter or motor overload caused by reactive power compensation is avoided.

[0165] Please refer to Figure 5 The application further provides a wind farm reactive power coordination method, device and storage medium for executing the above-mentioned wind farm reactive power coordination method, comprising:

[0166] A voltage drop monitoring module is configured to collect bus voltage and wind farm grid-connected point voltage in real time to calculate voltage drop amount, and limit active power output of non-fault fans when the voltage drop amount exceeds a set voltage drop amount threshold.

[0167] A reactive power margin distribution module is configured to calculate reactive power margin based on current reactive power output and maximum reactive power output capacity of each fan, calculate required reactive power compensation amount based on voltage drop amount, grid-connected point equivalent reactance and SVC maximum reactive power output capacity, and calculate reactive power distribution coefficient based on total number of fans and reactive power margin of each fan.

[0168] A coordinated compensation calculation module is configured to calculate fan reactive power adjustment amount based on current output of SVC, required reactive power compensation amount and current reactive power output of each fan, pre-set SVC reactive power compensation coefficient, and calculate SVC initial compensation amount based on SVC reactive power compensation coefficient and voltage drop amount.

[0169] A dynamic adjustment iteration module is configured to calculate fan reactive power compensation amount by using SVC initial compensation amount and required reactive power compensation amount, calculate adjustment reactive power output of each fan by using reactive power distribution coefficient and fan reactive power compensation amount, and iteratively optimize reactive power distribution.

[0170] The application further provides a storage medium having a computer program stored therein, wherein the computer program is executed by a processor to implement the above-mentioned wind farm reactive power coordination method.

[0171] The above-mentioned formulas are dimensionless values, and the formulas are obtained by software simulation of a large amount of data to obtain a formula of the nearest real situation, and the preset parameters in the formula are set by a person skilled in the art according to the actual situation.

[0172] The above-described embodiments can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented by software, the above-described embodiments can be implemented in whole or in part in the form of a computer program product. A person of ordinary skill in the art can be aware that units and algorithm steps of the examples described in connection with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on the specific application and design constraints of the technical solutions.

[0173] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, and can be located in one place or distributed on multiple network units. Part or all of the units can be selected to achieve the purpose of the embodiments according to actual needs.

[0174] The above is merely specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A reactive power coordination method for wind farms, characterized in that, The specific steps include: Step 1: Real-time acquisition of bus voltage and wind farm grid connection point voltage to calculate voltage drop. When the voltage drop exceeds the set voltage drop threshold, the active power output of non-faulty wind turbines is restricted. Step 2: Calculate the reactive power margin based on the current reactive power output and maximum reactive power output capacity of each wind turbine; calculate the required reactive power compensation based on voltage drop, grid connection point equivalent reactance and SVC maximum reactive power output capacity; and calculate the reactive power distribution coefficient based on the total number of wind turbines and the reactive power margin of each wind turbine. Step 3: Pre-set the SVC reactive power compensation coefficient, and calculate the initial SVC compensation amount based on the SVC reactive power compensation coefficient and voltage drop; Step 4: Calculate the reactive power compensation of the wind turbine using the initial SVC compensation amount and the required reactive power compensation amount. Calculate the adjusted reactive power output of each wind turbine using the reactive power distribution coefficient and the reactive power compensation amount of the wind turbine, and iteratively optimize the reactive power distribution. First, set the voltage drop threshold: In the formula, Indicates the rated coefficient. This represents the voltage drop threshold, where, ,when If the duration exceeds 50ms, a voltage drop fault is determined to have occurred. The faulty fan was located using the short-circuit current detection method. The output current of a specific fan was set to... ,in This represents the index of the wind turbines in the wind farm. This indicates the total number of wind turbines, and the short-circuit current threshold is set to... ,when At that time, determine the fan A malfunction occurred; Limit the active power output of non-faulty wind turbines and calculate the adjustment factor: In the formula, Indicates the adjustment factor. This represents the minimum constraint threshold, and ; Limit the active power output of non-faulty wind turbines: In the formula, This represents the active power output of each non-faulty wind turbine. This indicates a limitation on the active power output of non-faulty wind turbines.

2. The wind farm reactive power coordination method according to claim 1, characterized in that: The method for calculating voltage drop by real-time acquisition of bus voltage and wind farm grid connection point voltage is as follows: Real-time acquisition of wind farm bus voltage and wind farm grid connection point voltage, and calculation of voltage drop: In the formula, Indicates the rated voltage of the wind farm. This indicates the bus voltage of the wind farm. This indicates the grid-connected voltage of the wind farm. This indicates the voltage drop.

3. The wind farm reactive power coordination method according to claim 1, characterized in that: The method for calculating reactive power margin, required reactive power compensation, and reactive power distribution factor is as follows: Calculate the reactive power margin using the current reactive power output of each wind turbine and the maximum reactive power output capacity of each wind turbine: In the formula, Indicates the first The maximum reactive power output capacity of a typhoon turbine. Indicates the first The reactive power output of the typhoon generator Indicates the first The reactive power margin of a typhoon fan is the additional reactive power it can provide. At the same time, the reactive power margin of a faulty fan is set to 0. Record the equivalent reactance of the grid connection point, the maximum reactive power compensation capacity of the SVC, and calculate the required reactive power compensation: In the formula, Represents the equivalent reactance at the grid connection point. This indicates the maximum reactive power compensation capacity of the SVC. This indicates the required reactive power compensation. Finally, the reactive power distribution factor is calculated based on the total number of wind turbines and the reactive power margin of each turbine: In the formula, This represents the sum of the reactive power margins of all wind turbines. Indicates the first The reactive power margin of typhoon turbines Indicates the first The reactive power distribution factor of a typhoon generator.

4. The wind farm reactive power coordination method according to claim 3, characterized in that: The method for calculating the reactive power compensation of the wind turbine using the initial SVC compensation and the required reactive power compensation is as follows: Pre-set SVC reactive power compensation coefficient ,and Extract voltage drop Calculate the initial compensation amount for SVC: In the formula, Indicates the initial compensation amount of SVC; Extracting the initial compensation amount of SVC and required reactive power compensation Calculate the reactive power compensation of the wind turbine: In the formula, This indicates the required reactive power compensation. This indicates the amount of reactive power compensation required by the wind turbines, which is the additional amount of reactive power compensation that the wind turbines in the wind farm need to provide.

5. The wind farm reactive power coordination method according to claim 4, characterized in that: The method for calculating the adjusted reactive power output of each wind turbine using the reactive power distribution coefficient and the reactive power compensation of the wind turbine is as follows: Calculate the reactive power compensation for each wind turbine: In the formula, Indicates the first The amount of reactive power compensation that needs to be adjusted for typhoon turbines; Then the first The reactive power output of the typhoon generator after adjustment is: In the formula, Indicates the first Adjusting the reactive power output of the typhoon generator, i.e., the first The reactive power output of the typhoon generator after adjustment.

6. The reactive power coordination method for wind farms according to claim 5, characterized in that: The method for iteratively optimizing reactive power allocation is as follows: Monitoring the first The reactive power output after the typhoon was adjusted With the Maximum reactive power output of typhoon turbines The comparison results, when At that time, the judgment of the first The typhoon turbines have reached their reactive power output limit. The other turbines are categorized as turbines with room for adjustment, and reactive power output is redistributed accordingly. First, calculate the reactive power exceeding the maximum output: In the formula, Indicates the first The typhoon generator is exceeding its maximum reactive power output; Calculate the total reactive power margin of the new wind turbine: In the formula, This indicates a collection of wind turbines that still has room for adjustment. This indicates the total reactive power margin of the new wind turbine. Indicates the first The reactive power margin of typhoon turbines; Recalculate the reactive power distribution factor: In the formula, Indicates the new first The reactive power distribution factor of a typhoon generator; Finally, the excess reactive power is redistributed: In the formula, Indicates the first The reactive power output of the typhoon turbine exceeds its maximum reactive power output capacity. Indicates the first The reactive power that the typhoon generator needs to adjust beyond its upper limit, i.e., the new reactive power compensation that needs to be adjusted, includes... This indicates the number of the wind turbine that exceeds its maximum reactive power output capacity. This indicates the total number of wind turbines exceeding their maximum reactive power output capacity. Finally, calculate the new first... The reactive power output of the typhoon generator after adjustment is: In the formula, Indicates the new first The reactive power output of the typhoon generator after adjustment; If any wind turbine still exceeds its maximum reactive power output capacity, repeat all the initial monitoring steps until the reactive power output of all wind turbines no longer exceeds its maximum reactive power output capacity.

7. A reactive power coordination device for wind farms, characterized in that: The device is used to perform the wind farm reactive power coordination method according to any one of claims 1-6: The voltage drop monitoring module is used to collect the bus voltage and the grid connection point voltage of the wind farm in real time to calculate the voltage drop. When the voltage drop exceeds the set voltage drop threshold, the active power output of non-faulty wind turbines is restricted. The reactive power margin allocation module is used to calculate the reactive power margin based on the current reactive power output and maximum reactive power output capacity of each wind turbine, calculate the required reactive power compensation based on voltage drop, grid connection point equivalent reactance and SVC maximum reactive power output capacity, and calculate the reactive power allocation coefficient based on the total number of wind turbines and the reactive power margin of each wind turbine. The collaborative compensation calculation module is used to calculate the reactive power adjustment of the wind turbine based on the current reactive power output of the SVC, the required reactive power compensation amount, and the current reactive power output of each wind turbine. It also pre-sets the SVC reactive power compensation coefficient and calculates the initial compensation amount of the SVC based on the SVC reactive power compensation coefficient and the voltage drop. The dynamic adjustment iteration module is used to calculate the reactive power compensation of the wind turbine using the initial SVC compensation amount and the required reactive power compensation amount, calculate the adjusted reactive power output of each wind turbine using the reactive power distribution coefficient and the reactive power compensation amount of the wind turbine, and iteratively optimize the reactive power distribution.

8. A storage medium, characterized in that: The storage medium stores a computer program, which, when executed by a processor, implements the wind farm reactive power coordination method as described in any one of claims 1-6.

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