A reactive power compensation method, device, equipment and storage medium for a substation

Abstract

The present application provides a reactive power compensation method, device, equipment and storage medium for a substation, which belongs to the field of reactive power compensation for substations. The method includes: obtaining typical daily power grid operation data and the voltage operation curve issued by the dispatcher; comparing the power grid operation data with the voltage operation curve to screen out voltage limit points; determining voltage abnormality partitions according to the voltage limit points, and determining unreasonable sites according to the reactive power flow of the voltage abnormality partitions; determining the reactive power demand of the unreasonable site according to the relationship between the reactive power and the active power of the unreasonable site; and determining the reactive compensation plan according to the reactive power demand. The present application screens unreasonable sites based on typical daily data, and determines the reactive compensation plan by determining the reactive power demand of unreasonable sites, thereby improving the effectiveness and reliability of reactive compensation.

Description

Technical Field

[0001] The present application relates to the field of reactive power compensation for substations, and in particular to a reactive power compensation method, device, equipment and storage medium for substations. Background Art

[0002] With the construction of new power systems and large-scale Shagohuang bases, the installed capacity of new energy in the power grid has increased sharply, and the system's transmission power demand has increased sharply. The reactive compensation devices configured in old substations are mainly conventional fixed capacitors and reactors, and the reactive configuration capacity of some hub sites is insufficient, which makes it difficult to match the power grid structure and the rapid development of new energy.

[0003] In new power systems, especially those with a high proportion of renewable energy generation, the grid's reactive power regulation capacity is insufficient due to the volatility and intermittent nature of renewable energy generation. In addition, the wide geographical distribution of renewable energy generation such as wind power and photovoltaic power generation has led to an increase in power transmission distance, further exacerbating the problem of reactive power imbalance. Summary of the invention

[0004] The purpose of the present application is to overcome the problems existing in the above-mentioned prior art and to provide a reactive power compensation method, device, equipment and storage medium for a substation.

[0005] The present application provides a reactive power compensation method for a substation, comprising:

[0006] Obtain typical daily grid operation data and voltage operation curves issued by dispatch;

[0007] Comparing the power grid operation data with the voltage operation curve to screen out voltage limit points;

[0008] Determine a voltage abnormality zone according to the voltage crossing point, and determine an unreasonable site according to reactive power flow conditions in the voltage abnormality zone;

[0009] Determining the reactive power demand of the unreasonable site according to the relationship between the reactive power and the active power of the unreasonable site;

[0010] A reactive power compensation scheme is determined according to the reactive power demand.

[0011] Optionally, determining the reactive power demand of the unreasonable site according to the relationship between the reactive power and the active power of the unreasonable site includes:

[0012] Calculate the reactive power absorbed externally by the unreasonable site under different active power conditions;

[0013] Calculating the line voltage of the unreasonable site under different active power conditions;

[0014] Calculating a reactive power balance relationship according to the reactive power and the line voltage under different active power conditions;

[0015] The reactive power demand of the unreasonable site is determined according to the power grid operation data and the reactive power balance relationship.

[0016] Optionally, the reactive power balance relationship is calculated, and the expression is as follows:

[0017] Q CH +Q CO +Q LO =Q SYS

[0018] Where: Q CH Charging power for the transmission line, Q CO For reactive power compensation of line high and low reactors, Q LO is the reactive power loss of the line and transformer, Q SYS is the reactive power delivered to the system;

[0019] In the above relationship, the capacitive quantity is positive and the inductive quantity is negative.

[0020] Optionally, a reactive power compensation scheme is determined according to the reactive power demand, and the expression is as follows:

[0021] Q 补偿 =-(Q ch * +Q LLoss * +Q TLoss * +Q 110上送 * +Q K * )×S B

[0022] Among them, Q K * S is the line high impedance B is the base capacity of the main transformer, Q ch * is the capacitive charging power of the line, Q TLoss * is the inductive transformer loss, Q LLoss * is the inductive line loss, Q 110上送 * Send reactive power to the main transformer.

[0023] Optionally, determining a reactive power compensation scheme according to the reactive power demand includes:

[0024] When the reactive power demand is less than or equal to a preset threshold, the reactive power exchange of the system is controlled within a certain range by adjusting the low voltage reactive power compensation capacity;

[0025] When the reactive power demand is greater than a preset threshold, the reactive power exchange of the system is controlled within a certain range by adding capacitive reactive power compensation equipment.

[0026] Optionally, determining a reactive power compensation scheme according to the reactive power demand includes:

[0027] Determine the scale and type of additional reactive power compensation equipment.

[0028] Optionally, determine the scale and type of additional reactive power compensation equipment, including:

[0029] The scale and type of reactive power compensation devices are arranged in the PSASP program data to simulate extreme operation modes and verify the effectiveness of the configuration scheme.

[0030] The present application also provides a reactive power compensation device for a substation, comprising:

[0031] The acquisition module is used to obtain typical daily power grid operation data and the voltage operation curve issued by the dispatcher;

[0032] A screening module, used for comparing the power grid operation data with the voltage operation curve, and screening out voltage limit-crossing points;

[0033] A judgment module, used to determine the voltage abnormality partition according to the voltage limit crossing point, and determine the unreasonable site according to the reactive power flow of the voltage abnormality partition;

[0034] A calculation module, used to determine the reactive power demand of the unreasonable site according to the relationship between the reactive power and the active power of the unreasonable site;

[0035] A scheme module is used to determine a reactive power compensation scheme according to the reactive power demand.

[0036] The present application also provides a reactive power compensation device for a substation, comprising:

[0037] A memory, used for storing a computer executable program of the reactive power compensation method for a substation;

[0038] The processor is used to obtain the computer executable program from the memory and execute, including: obtaining typical daily power grid operation data and the voltage operation curve issued by the dispatcher; comparing the power grid operation data with the voltage operation curve to screen out voltage limit points; determining voltage abnormality partitions according to the voltage limit points, and determining unreasonable sites according to the reactive power flow of the voltage abnormality partitions; determining the reactive power demand of the unreasonable site according to the relationship between the reactive power and the active power of the unreasonable site; and determining a reactive compensation plan according to the reactive power demand.

[0039] The present application also provides a storage medium storing a computer executable program, wherein the computer executable program is used to be called by a processor to execute the steps of the above-mentioned reactive power compensation method for a substation.

[0040] The beneficial effects of this application are:

[0041] The present application provides a reactive power compensation method for a substation, including: obtaining typical daily power grid operation data and a voltage operation curve issued by a dispatcher; comparing the power grid operation data with the voltage operation curve to screen out voltage limit points; determining voltage abnormality partitions according to the voltage limit points, and determining unreasonable sites according to reactive power flow conditions of the voltage abnormality partitions; determining reactive power requirements of the unreasonable sites according to the relationship between reactive power and active power of the unreasonable sites; and determining reactive compensation schemes according to the reactive power requirements. The present application screens unreasonable sites based on typical daily data, and determines reactive compensation schemes based on reactive power requirements of unreasonable sites, thereby improving the effectiveness and reliability of reactive compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic diagram of the reactive power compensation process of the substation in this application;

[0043] Figure 2 It is a schematic diagram of the relationship between reactive output and transmission power in this application;

[0044] Figure 3 It is a schematic diagram of the PV curve in this application;

[0045] Figure 4 It is a schematic diagram of the substation structure in this application. DETAILED DESCRIPTION

[0046] The present application is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present application and implement it.

[0047] The present application provides a reactive power compensation method for a substation, which belongs to the field of reactive power compensation for substations and is used to solve the technical problem that the old reactive power compensation method is not suitable for reactive power compensation in a new energy power grid.

[0048] Please refer to Figure 1 As shown, the present application provides a reactive power compensation method for a substation, the steps comprising:

[0049] S101. Obtain typical daily power grid operation data and voltage operation curve issued by the dispatcher.

[0050] The D5000 platform is an advanced power grid dispatching automation system used to monitor, control and manage the operation of the power grid. The D5000 platform has functions such as data collection, processing, analysis and display, which can help dispatchers understand the operation status of the power grid in real time and discover and handle problems in a timely manner.

[0051] In this application, the D5000 platform is used to collect grid operation data of lines of different voltage levels in a specific grid area or system that needs to be analyzed, including 750 ultra-high voltage lines and 330 high voltage lines.

[0052] The power grid operation data includes: the actual operation active power and reactive power data sent up / down by the main transformer. The main transformer is the main transformer, which is an important device in the power grid.

[0053] In the above content, uplink and downlink refer to the direction of power transmission. Active power and reactive power are two important parameters that describe the characteristics of power transmission. Active power is used to do work, such as driving motors and emitting light, while reactive power is used to establish and maintain the magnetic field in the power grid, which is crucial for the stable operation of the power grid.

[0054] After the power grid operation data is collected, the time series data is decomposed into trend components, seasonal components and random components through seasonal decomposition. In the analysis of power grid operation data, since factors such as weather and load in different seasons will affect the operation of the power grid, seasonal decomposition can better understand and predict the operation law of the power grid.

[0055] After completing the seasonal decomposition, a clustering algorithm is used to divide the data into different groups or categories. In the analysis of power grid operation data, clustering algorithms can be used to identify typical daily data under different operation modes. These typical daily data can represent the operation characteristics of the power grid under different conditions, which is of great significance for formulating dispatch strategies and optimizing resource allocation.

[0056] Finally, based on the results of seasonal decomposition and clustering algorithms, representative typical daily power grid operation data are selected. These data can reflect the operation status of the power grid in different seasons and under different load conditions.

[0057] The voltage operation curve issued by the dispatcher is an important dispatch instruction in the power system. It specifies in detail the operating level that the voltage of each node in the power grid should reach or maintain within a specific time period. This curve is of great significance for ensuring the stable operation of the power system, optimizing resource allocation and improving power supply quality.

[0058] S102: Screen out voltage limit-crossing points by comparing the grid operation data with the voltage operation curve.

[0059] Compare the grid operation data with the voltage operation curve to screen out the voltage limit points.

[0060] When comparing data, the grid operation data is matched with the voltage operation curve in time. Ensure that the corresponding time points of the two are consistent so that an accurate comparison can be made. Then, the voltage values ​​in the grid operation data are compared one by one with the voltage values ​​at the corresponding time points in the voltage operation curve.

[0061] When comparing the grid operation data with the voltage operation curve based on time series data, small deviations in time are processed by dynamic time warping. The dynamic time warping (DTW) algorithm allows nonlinear stretching or compression of the sequence on the time axis to find the best alignment between the two sequences.

[0062] The traditional DTW algorithm uses the Euclidean distance as a measure of the similarity between two sequence points.

[0063] In this application, in the comparison of power grid operation data, the distribution and correlation of new energy grid data are relatively complex. Therefore, Mahalanobis distance is used to replace Euclidean distance. The expression of Mahalanobis distance is as follows:

[0064]

[0065] Among them, i and j are vectors composed of two data points, S is the covariance matrix of the data, the superscript T represents the transpose, S- 1 represents the inverse of the covariance matrix.

[0066] In this application, the phase weight wphas is introduced e To adjust the Mahalanobis distance. The phase weight is dynamically calculated according to the size of the phase difference. The weight calculation formula is as follows:

[0067]

[0068] The adjusted Mahalanobis distance calculation formula is:

[0069] MD'[i][j]=MD[i][j]×wphase(i,j)

[0070] Among them, w phase (i,j) is the phase weight between the i-th point in Q′ and the j-th point in C′.

[0071] In the dynamic time warping algorithm combined with Mahalanobis distance, the cumulative distance matrix is ​​calculated as follows:

[0072] Assume that there are two time series Q and C, with lengths of n and m respectively, and their covariance matrix S has been calculated. Q and S C .

[0073] Create a (n+1)×(m+1) cumulative distance matrix DTW, where all elements are initialized to infinity except DTW[0][0] which is set to 0.

[0074] Before actually calculating the cumulative distance matrix, an n×m Mahalanobis distance matrix MD is calculated first, where MD[i][j] represents the Mahalanobis distance between the i-th point in Q and the j-th point in C. In the subsequent dynamic programming process, the values ​​in this matrix are directly searched without repeatedly calculating the Mahalanobis distance.

[0075] For each position (i, j) in the cumulative distance matrix DTW, update its value according to the following rules:

[0076] If i=0 and j=0, then DTW[i][j]=0 (initialization value).

[0077] If i=0 and j>0, then DTW[i][j]=DTW[i][j-1]+MD[i][j] (only the C sequence advances one step).

[0078] If i>0 and j=0, then DTW[i][j]=DTW[i-1][j]+MD[i][j] (only the Q sequence advances one step).

[0079] If i>0 and j>0, then: DTW[i][j]=MD[i][j]+min(DTW[i-1][j], DTW[i][j-1], DTW[i-1][j-1]) (both C sequence and Q sequence advance one step).

[0080] Finally, select the value with the smallest cumulative distance among the three paths, and then add it to the Mahalanobis distance MD[i][j] of the current point (i, j) to get the value of DTW[i][j]. The mathematical expression is as follows:

[0081] DTW[i][j]=MD[i][j]+min(DTW[i-1][j],DTW[i][j-1],DTW[i-1][j-1])

[0082] The min function is used to find the minimum value among the three cumulative distances. The minimum value represents the cumulative distance on the optimal path to the current point (i, j).

[0083] Furthermore, in order to avoid excessive distortion of the shape of the time series, a time window constraint is introduced. The time window constraint limits the mapping range of the time warping function φ, ensuring that the aligned path does not deviate too far.

[0084] Specifically, a window size w is set so that for any two aligned points Q i and C j , the difference between the two indices |ij| must be less than or equal to w.

[0085] The DTW algorithm with time window constraint can be described as follows:

[0086] Initialize an (n+1)×(m+1) cumulative distance matrix DTW, where all elements are initialized to infinity except DTW[0][0] which is set to 0.

[0087] For each position (i, j) in the matrix, calculate the Mahalanobis distance DM(Q i ,C j ), where Q i and C j are the values ​​of the two time series Q and C at index i and j respectively.

[0088] Use dynamic programming to calculate the cumulative distance matrix. For each (i, j), its previous state (i-1, j), (i, j-1) and (i-1, j-1), select those states that meet the time window constraint. Then, select the path with the smallest cumulative distance as the optimal path for the current state.

[0089] The cumulative distance update formula with time window constraints can be expressed as:

[0090]

[0091] The max(0,jw) and min(i+w,n) operations ensure that the index does not exceed the range of the sequence and satisfies the time window constraint.

[0092] Finally, the obtained DTW[n][m] is the total distance of the optimal matching path between the two time series.

[0093] In the process of comparing the grid operation data with the voltage operation curve, if the voltage value in the grid operation data is found to exceed the range specified by the voltage operation curve, the point is considered to be a voltage over-limit point. Through comparison and analysis, all voltage over-limit points are screened out.

[0094] S103: Determine a voltage abnormality zone according to the voltage crossing point.

[0095] When a voltage crossing point is identified, it is determined whether it is a typical power flow based on the grid operation data. If so, the crossing point is analyzed spatially and temporally to determine the area or partition with abnormal voltage. Specifically, the partition is determined based on the topological structure of the grid. The area with abnormal voltage is accurately located through partitioning.

[0096] S104: Compare the reactive power flow value in the voltage abnormality zone with the reactive power theoretical calculation value to determine the unreasonable site.

[0097] Reactive power plays an important role in maintaining voltage stability in the power system. When voltage anomalies occur in the power grid, the flow of reactive power tends to change. By analyzing the flow of reactive power, we can identify those sites that contribute more to voltage anomalies, i.e., unreasonable sites.

[0098] The reactive power flow data includes the reactive power input, output and flow direction of each node. According to the topological structure, equipment parameters and load conditions of the power grid, the reactive power theoretical calculation value of each node can be obtained by using power system analysis software or manual calculation. The calculation formula of reactive power (Q) is:

[0099] Q=V*I*sin(θ)

[0100] Where: Q is reactive power, V is voltage, I is current, and θ is the phase angle between voltage and current.

[0101] These calculated values ​​reflect the reactive power levels that each node should have under ideal conditions.

[0102] Compare the actual reactive power flow value with the theoretical calculated value point by point, and analyze the difference and change trend between them. If the difference is large or the change trend is abnormal, it means that the reactive power configuration of the node or area is unreasonable.

[0103] By combining the voltage anomaly zoning and reactive power comparison results, nodes with both voltage exceeding the limit and unreasonable reactive power configuration are screened out.

[0104] S105: Determine the reactive power demand of the unreasonable site according to the relationship between the reactive power and the active power of the unreasonable site.

[0105] When the unreasonable site is determined, or it is judged that it is not a typical power flow (judged to be an extreme operation mode) according to the power grid operation data, the calculation steps of the reactive power demand are as follows:

[0106] The first step is to calculate the reactive power absorbed by the unreasonable site (including a single site in extreme operation mode) under different active power conditions:

[0107]

[0108] in, is the transmission line charging power; is the reactive power loss of the line and transformer; Q CO =80%Q CH It is the reactive power compensation of high impedance and low capacitance (resistance) of the line.

[0109] Let Q SYS =0, the line transmission power Pz is obtained, the reactive power loss is equal to the reactive power generated by the line capacitance and the reactive compensation equipment, the reactive exchange between the system and the outside world is zero, and no additional reactive compensation is required.

[0110] When P<P Z When , the unreasonable site sends out reactive power, and the reactive power output is negative;

[0111] When P>P Z When , the reactive power of unreasonable sites is insufficient, and the reactive power output of unreasonable sites is positive.

[0112] Through simulation calculation, the unreasonable site reactive output under different line transmission powers is obtained. Figure 2 The relationship curve between reactive output and transmission power is shown.

[0113] The second step is to calculate the line voltage of the unreasonable site under different active power conditions.

[0114] When the transmission power is small, the change rate of reactive output with the transmission power is relatively small; when the transmission power is large, the change rate of reactive output with the transmission power is relatively large. As the transmission power increases, the reactive loss continues to increase. If there is not enough reactive compensation equipment, the required reactive power can only be absorbed from the system, which will increase the reactive pressure of the system.

[0115] By adjusting the active output of the generator, the line transmission power changes from small to large, and the relationship between line voltage and transmission power is studied. The line voltage under different line transmission powers is obtained through simulation calculation, and the following is obtained: Figure 3 PV curve diagram shown.

[0116] like Figure 3As shown in the figure, as the transmission power increases, the rate of change of the line voltage gradually increases; when the transmission power is small, the rate of change of the line voltage is relatively small; when the transmission power is large, the rate of change of the line voltage is relatively large. In the case of insufficient reactive compensation, the voltage of the high-voltage and high-power transmission line will drop rapidly as the transmission power increases, so it is necessary to take measures to increase reactive compensation to maintain the line voltage.

[0117] The third step is to calculate the reactive power balance relationship according to the reactive power and the line voltage under different active power conditions.

[0118] For sites with unreasonable reactive power flow, the reactive power demand of specific substations is further analyzed through the reactive power balance theoretical calculation method taking into account the high-power flow of new energy.

[0119] Reactive power includes the charging power of the transmission line, reactive compensation of high-capacitor and low-capacitor (resistance) of the line, reactive loss of the line and transformer, and reactive exchange with the system. The regional reactive balance relationship is:

[0120] Q CH +Q CO +Q LO =Q SYS

[0121] Where: Q CH - Transmission line charging power, unit: Mvar; Q CO - Line high-resistance and low-capacitance (resistance) reactive power compensation, unit: Mvar; Q LO - Reactive power loss of lines and transformers, unit: Mvar; Q SYS - Reactive power delivered to the system, unit: Mvar.

[0122] In the above relationship, the capacitive quantity is positive and the inductive quantity is negative.

[0123] Step 4: determining the reactive power demand of the unreasonable site according to the grid operation data and the reactive power balance relationship.

[0124] Generalized natural power is a special form of reactive power balance: the reactive power consumed by the transmission line and transformer is exactly equal to the reactive power generated by the line capacitor and reactive power compensation equipment, and the reactive power exchange between the transmission and transformation system and the outside world is zero, that is:

[0125] Q CH +Q CO +Q LO =0

[0126] Based on the above formula, taking the reactive exchange between the power transmission and transformation system and the outside world as zero boundary, the reactive components of the power transmission and transformation system are calculated for different power levels transmitted by the lines, and regional reactive balance analysis is performed to determine the reactive power demand of the system.

[0127] S106: Determine a reactive power compensation scheme according to the reactive power demand.

[0128] By analyzing the relationship between the active power and reactive power of the actual operating line, the reactive power exchange of the system can be controlled within a certain power range by adjusting the low-voltage reactive compensation capacity.

[0129] However, for some sites, reactive power loss continues to increase with the increase in power. Since there is no more low-capacitance compensation, the required reactive power can only be absorbed from the system. The increase in reactive power demand brings great reactive pressure to the systems on both sides, requiring increased investment in capacitive reactive power compensation equipment.

[0130] Please refer to Figure 4 As shown, substation A is taken as an example to further illustrate the method of adding reactive power compensation devices.

[0131] Station A has two 330 kV outgoing lines. There is a line high-voltage reactor on the outgoing line #1, which provides reactive power of Q K , the active power flowing in the two lines is P1 and P2; the active power sent to the medium voltage side of the transformer at station A is P 110上送 , the reactive power sent up is Q 110上送 .

[0132] Calculate the capacitive charging power Q of the line through the line parameters ch * and inductive line loss Q LLoss * ,Right now

[0133]

[0134] The inductive transformer loss Q is calculated by the main transformer flow power and main transformer parameters. TLOSS * and 110 kV voltage level to send reactive power Q 110输入 * ;

[0135] Q is obtained by line high impedance parameters K * ;

[0136] The reactive power required to be compensated for substation A is obtained as follows:

[0137] Q 补偿 =-(Q ch * +Q LLoss *+Q TLoss * +Q 110上送 * +Q K * )×S B .

[0138] Then, according to the above reactive power demand, determine whether to add reactive power compensation equipment.

[0139] Furthermore, we need to deeply understand and analyze the grid boundary conditions (such as voltage limits, power limits, etc.) and historical operation characteristics (such as load changes, fault records, etc.) of specific areas. Based on the above conditions, through a series of calculations and analyses, we can determine the scale and type of reactive power compensation devices that need to be added, including: capacitive charging power (reflecting the charging needs of capacitors and other equipment), inductive line loss (power loss caused by line inductance), transformer loss (loss generated by transformer during operation), and high-voltage reactor parameters (parameters related to high-voltage equipment).

[0140] Ensure that the added reactive power compensation device can not only meet the reactive power demand of the power grid under normal operation, but also provide necessary reactive power support under AC and DC fault operation. Use PSASP for simulation:

[0141] PSASP is a software tool for power system analysis and simulation. Using this software, combined with the future power grid power flow distribution requirements, the calculated reactive power increase scheme is arranged in the PSASP program data to simulate extreme operation modes. This helps to verify the effect of the configuration scheme in actual operation.

[0142] After simulation, if the configuration scheme is proven to be appropriate, the additional reactive power type and capacity can be applied to the next step of the project. Based on the simulation results, a detailed project implementation plan can be formulated, including equipment procurement, installation and commissioning, operation and maintenance, etc.

[0143] The present application also provides a reactive power compensation device for a substation, comprising:

[0144] The acquisition module is used to obtain typical daily power grid operation data and the voltage operation curve issued by the dispatcher;

[0145] A screening module, used for comparing the power grid operation data with the voltage operation curve, and screening out voltage limit-crossing points;

[0146] A judgment module, used to determine the voltage abnormality partition according to the voltage limit crossing point, and determine the unreasonable site according to the reactive power flow of the voltage abnormality partition;

[0147] A calculation module, used to determine the reactive power demand of the unreasonable site according to the relationship between the reactive power and the active power of the unreasonable site;

[0148] A scheme module is used to determine a reactive power compensation scheme according to the reactive power demand.

[0149] The present application also provides a reactive power compensation device for a substation, comprising:

[0150] A memory, used for storing a computer executable program of the reactive power compensation method for a substation;

[0151] The processor is used to obtain the computer executable program from the memory and execute, including: obtaining typical daily power grid operation data and the voltage operation curve issued by the dispatcher; comparing the power grid operation data with the voltage operation curve to screen out voltage limit points; determining voltage abnormality partitions according to the voltage limit points, and determining unreasonable sites according to the reactive power flow of the voltage abnormality partitions; determining the reactive power demand of the unreasonable site according to the relationship between the reactive power and the active power of the unreasonable site; and determining a reactive compensation plan according to the reactive power demand.

[0152] The present application also provides a storage medium storing a computer executable program, wherein the computer executable program is used to be called by a processor to execute the steps of the above-mentioned reactive power compensation method for a substation.

Claims

1. A reactive power compensation method for a substation, characterized in that: include: Obtain typical daily grid operation data and voltage operation curves issued by dispatch; By comparing the power grid operation data with the voltage operation curve, a voltage exceeding limit point is screened out; Determine the voltage abnormality zone according to the voltage limit crossing point; Compare the reactive power flow value in the voltage abnormality zone with the reactive power theoretical calculation value to determine the unreasonable site; Determining the reactive power demand of the unreasonable site according to the relationship between the reactive power and the active power of the unreasonable site, including: calculating the reactive power and line voltage absorbed externally by the unreasonable site under different active power conditions; calculating the reactive balance relationship according to the reactive power and the line voltage under different active power conditions; determining the reactive power demand of the unreasonable site according to the power grid operation data and the reactive balance relationship; A reactive power compensation scheme is determined according to the reactive power demand.

2. The reactive power compensation method for a substation according to claim 1, characterized in that: Calculate the reactive power balance relationship, the expression is as follows: Q CH +Q CO +Q LO =Q SYS Where: Q CH Charging power for the transmission line, Q CO For reactive power compensation of line high and low reactors, Q LO is the reactive power loss of the line and transformer, Q SYS is the reactive power delivered to the system; In the above relationship, the capacitive quantity is positive and the inductive quantity is negative.

3. The reactive power compensation method for a substation according to claim 1, characterized in that: Determine the reactive power compensation scheme according to the reactive power demand, and the expression is as follows: Q 补偿 =-(Q ch * +Q LLoss * +Q TLoss * +Q 110上送 * +Q K * )×S B Among them, Q K * S is the line high impedance B is the base capacity of the main transformer, Q ch * is the capacitive charging power of the line, Q TLoss * is the inductive transformer loss, Q LLoss * is the inductive line loss, Q 110上送 * Send reactive power to the main transformer.

4. The reactive power compensation method for a substation according to claim 1, characterized in that: Determining a reactive power compensation scheme according to the reactive power demand includes: If the reactive power demand is less than or equal to a preset threshold, the reactive power exchange of the system is controlled within a certain range by adjusting the low voltage reactive power compensation capacity; When the reactive power demand is greater than a preset threshold, capacitive reactive power compensation equipment is added to control the reactive power exchange of the system within a certain range.

5. The reactive power compensation method for a substation according to claim 1, characterized in that: Determining a reactive power compensation scheme according to the reactive power demand includes: Determine the scale and type of additional reactive power compensation equipment.

6. The reactive power compensation method for a substation according to claim 5, characterized in that: Determine the scale and type of additional reactive power compensation equipment, including: The scale and type of reactive power compensation devices are arranged in the PSASP program data to simulate extreme operation modes and verify the effectiveness of the configuration scheme.

7. A reactive power compensation device for a substation, characterized in that: include: The acquisition module is used to obtain typical daily power grid operation data and the voltage operation curve issued by the dispatcher; A screening module, used for comparing the power grid operation data with the voltage operation curve, and screening out voltage limit-crossing points; A judgment module, used to determine the voltage abnormality partition according to the voltage limit crossing point, and determine the unreasonable site according to the reactive power flow of the voltage abnormality partition; A calculation module is used to determine the reactive power demand of the unreasonable site according to the relationship between the reactive power and the active power of the unreasonable site, including: calculating the reactive power and line voltage absorbed externally by the unreasonable site under different active power conditions; calculating the reactive balance relationship according to the reactive power and the line voltage under different active power conditions; determining the reactive power demand of the unreasonable site according to the power grid operation data and the reactive balance relationship; A scheme module is used to determine a reactive power compensation scheme according to the reactive power demand.

8. A reactive power compensation device for a substation, characterized in that: include: A memory for storing a computer executable program of a reactive power compensation method for a substation according to any one of claims 1 to 6; The processor is used to obtain the computer executable program from the memory and execute, including: obtaining typical daily power grid operation data and the voltage operation curve issued by the dispatcher; and screening out voltage limit points by comparing the power grid operation data with the voltage operation curve; Determine the voltage abnormality zone according to the voltage crossing point, and determine the unreasonable site based on the comparison result of the reactive power flow value in the voltage abnormality zone with the reactive power theoretical calculation value; determine the reactive power demand of the unreasonable site according to the relationship between the reactive power and the active power of the unreasonable site; determine the reactive compensation plan according to the reactive power demand.

9. A storage medium, characterized in that: A computer executable program is stored, and the computer executable program is used to be called by a processor to execute the steps of a reactive power compensation method for a substation as described in any one of claims 1 to 6.

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