A power system substation reactive power compensation method

Abstract

This invention relates to the field of dynamic reactive power compensation technology, specifically a reactive power compensation method for power system substations. Based on the voltage fluctuation characteristic index of each bus section of the power system substation within a set historical time period, and considering the type of reactive power compensation device, corresponding reactive power compensation devices are connected to each bus section. The measured voltage of each bus section is collected. If reactive power compensation is required, a first reactive power compensation amount is calculated and output based on the voltage-reactive power sensitivity coefficient of each reactive power compensation device. When the power factor is unqualified, the active power at the grid connection point is obtained and combined with the current power factor at the grid connection point on the high-voltage side of the main transformer to calculate the total reactive power compensation required for the substation. The total reactive power compensation deficit is analyzed based on the first reactive power compensation amount. A corresponding second reactive power compensation amount is allocated based on the remaining reactive power capacity of the reactive power compensation devices on each bus section, and the corresponding second reactive power compensation amount is output, thereby improving the overall reactive power compensation effect.

Description

Technical Field

[0001] This invention relates to the field of dynamic reactive power compensation technology, and specifically to a reactive power compensation method for power system substations. Background Technology

[0002] In the operation of a power system, the operational stability and power quality of substations determine the reliability of the entire power network. Reactive power balance and regulation are crucial for ensuring the efficient operation of substations and the entire power system. Reactive power imbalance can lead to a series of problems, such as bus voltage fluctuations, low power factor, and increased line losses. This not only reduces the operating efficiency of power equipment but can also cause voltage collapse, equipment overload failures, and disrupt normal electricity use for industrial and commercial production and residential life. Therefore, reactive power compensation technology in substations has become a core research and application direction in the field of power system control.

[0003] Existing technologies, such as Chinese Patent Publication No. CN121055364A, disclose a reactive power compensation method based on fluctuating renewable distributed power sources connected to a distribution network. This method determines the power factor calculation point and power adjustment standard; then obtains the total active and reactive power of the load, distributed power sources, and transformer calculation points to calculate the total reactive power demand and compensation amount; finally, it uses a multiple-loop exhaustive search method to traverse variable combinations and selects the compensation capacity with the largest absolute value as the optimal configuration. This method considers the real-time changes in load and distributed power sources and accurately calculates the optimal compensation capacity.

[0004] However, the existing technology has the following problems: 1. The existing technology calculates the reactive power compensation requirement based on the power factor, without taking into account the characteristics of voltage fluctuations when performing reactive power compensation. As a result, in the process of pursuing the power factor target, the stability of the bus voltage is ignored, resulting in problems such as low utilization of compensation resources and aggravated voltage fluctuations.

[0005] 2. Existing technologies mostly only consider the remaining capacity when allocating reactive power compensation, without taking into account the impact of bus fluctuation characteristics. This can easily lead to unreasonable utilization of the remaining capacity of the device, making it unable to cope with subsequent voltage fluctuations. This not only reduces the accuracy and effectiveness of compensation, but also shortens the service life of the reactive power compensation device and increases equipment operation and maintenance costs. Summary of the Invention

[0006] This invention aims to address the shortcomings of existing technologies by providing a reactive power compensation method for power system substations. It achieves the dual objectives of stabilizing bus voltage across all sections of the substation and ensuring the power factor at the high-voltage side of the main transformer meets standards, thereby improving the accuracy and systematic nature of reactive power compensation and guaranteeing the safe and efficient operation of the power system.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a reactive power compensation method for power system substations, comprising: analyzing the voltage fluctuation characteristic index of each bus section of the substation within a set historical time period, and connecting the corresponding reactive power compensation device to each bus section in combination with the type of reactive power compensation device.

[0008] Collect the measured voltage of each bus section to determine whether reactive power compensation is required. If reactive power compensation is required, calculate and output the corresponding first reactive power compensation amount based on the voltage-reactive power sensitivity coefficient of each reactive power compensation device.

[0009] Obtain the current grid connection point power factor and reactive power on the high-voltage side of the main transformer. Combine the target power factor to determine whether the grid connection point power factor is qualified. If the power factor is not qualified, obtain the active power at the grid connection point and calculate the total reactive power that the substation should compensate.

[0010] The total reactive power compensation deficit is analyzed based on the total reactive power compensation amount of the substation and the first reactive power compensation amount of the reactive power compensation device of each bus section.

[0011] Based on the total reactive power compensation deficit and the remaining reactive power capacity of the reactive power compensation devices of each bus section, the second reactive power compensation amount of the corresponding reactive power compensation device is allocated in combination with the fluctuation characteristic index of each bus section, and the corresponding second reactive power compensation amount is output.

[0012] Furthermore, the analysis method for the fluctuation characteristic index is as follows: obtain the voltage of each bus section with the same voltage level in the power system substation within a set historical time period from the power system background database.

[0013] The voltage difference at each time point is calculated by comparing the voltage of each bus section with the rated bus voltage within a set historical time period, forming a voltage difference sequence.

[0014] The ratio of the maximum absolute value of the voltage difference sequence of each bus segment to the rated bus voltage is denoted as the fluctuation amplitude factor.

[0015] Based on the rated bus voltage, the allowable voltage fluctuation range is set, and the number of times the voltage difference sequence of each bus segment exceeds the allowable fluctuation range is counted. The fluctuation frequency factor of each bus segment is calculated by comparing the number of times the fluctuation exceeds the allowable fluctuation range with the total time points of the set historical time period.

[0016] The volatility characteristic index is obtained by weighting and summing the volatility amplitude factor and volatility frequency factor of each bus line segment.

[0017] Furthermore, the connection method of the reactive power compensation device is as follows: sort each bus segment in descending order according to the fluctuation characteristic index, and group the sorted bus segments based on the preset type and number of reactive power compensation devices to obtain each bus segment group.

[0018] The reactive power compensation devices are assigned to each bus group in descending order of rated capacity, and all buses in each bus group are connected to the reactive power compensation device of the corresponding assigned type.

[0019] Furthermore, the analysis method for the first reactive power compensation is as follows: the current voltage difference is obtained by calculating the difference between the measured voltage of each bus section and the rated bus voltage.

[0020] If the current voltage difference of a certain bus section is within the allowable voltage fluctuation range, then it is determined that the bus section does not need reactive power compensation; otherwise, it is determined that reactive power compensation is required.

[0021] When a busbar section needs reactive power compensation, the ratio of the current voltage difference of the busbar section to the corresponding voltage-reactive power sensitivity coefficient is analyzed to obtain the first reactive power compensation amount of the reactive power compensation device corresponding to the busbar section.

[0022] Furthermore, the method for obtaining the voltage-reactive power sensitivity coefficient includes: extracting historical reactive power compensation records of each busbar's reactive power compensation device within a set historical time period from the power system's backend database.

[0023] The inductive reactive power absorbed during each reactive power compensation process and the bus voltage change during each reactive power compensation were screened from the historical reactive power compensation records of each reactive power compensation device.

[0024] The ratio of the bus voltage change to the absorbed inductive reactive power of each reactive power compensation device during each reactive power compensation process is statistically analyzed. After removing outliers, the average of the remaining ratios is recorded as the voltage-reactive power sensitivity coefficient of each reactive power compensation device.

[0025] Furthermore, the method for obtaining the total reactive power to be compensated includes: extracting the target power factor and current reactive power of the grid connection point on the high-voltage side of the main transformer from the power system background database.

[0026] If the current power factor at the grid connection point on the high-voltage side of the main transformer is greater than the target power factor and the current reactive power is greater than or equal to zero, then the current power factor is deemed qualified; otherwise, the current power factor is deemed unqualified.

[0027] When the current power factor is not up to standard, the target reactive power is calculated based on the target power factor and the active power at the grid connection point, and the difference between the target reactive power and the current reactive power is recorded as the total reactive power to be compensated.

[0028] Furthermore, the method for obtaining the total reactive power compensation deficit is as follows: the first reactive power compensation amounts of the reactive power compensation devices of each bus section are vector-summed and recorded as the total actual compensation amount.

[0029] If the total actual compensation amount and the total reactive power compensation amount have the same sign, and the absolute value of the total actual compensation amount is greater than or equal to the absolute value of the total reactive power compensation amount, then the total reactive power compensation deficit is recorded as zero.

[0030] Conversely, the difference between the total reactive power compensation amount and the total actual compensation amount is recorded as the total reactive power compensation deficit.

[0031] Furthermore, the method for obtaining the remaining reactive power capacity includes: when the first reactive power compensation amount of a certain reactive power compensation device has the opposite sign to the total reactive power compensation deficit, the rated capacity of the device is taken as the remaining reactive power capacity.

[0032] When the first reactive power compensation amount of a certain reactive power compensation device has the same sign as the total reactive power compensation deficit, the difference between the rated capacity of the device and the absolute value of the first reactive power compensation amount is recorded as the remaining reactive power capacity.

[0033] Furthermore, the method for obtaining the second reactive power compensation amount includes: comprehensively analyzing the fluctuation-weighted remaining capacity based on the remaining reactive power capacity of the reactive power compensation device of each bus section combined with the fluctuation characteristic index.

[0034] The sum of the fluctuation-weighted residual capacity of the reactive power compensation devices of all buses is recorded as the total residual reactive power capacity.

[0035] The ratio of the fluctuation-weighted residual capacity of the reactive power compensation device of each bus section to the total residual reactive power capacity is recorded as the allocation ratio.

[0036] The corresponding second reactive power compensation amount is obtained by multiplying the distribution ratio of the reactive power compensation device of each bus section with the total reactive power compensation deficit.

[0037] Furthermore, the analysis method for the volatility-weighted remaining capacity is as follows: calculate the sum of the volatility characteristic indices of each segment of the bus line as the total volatility characteristic index, obtain the difference between the total volatility characteristic index and the volatility characteristic index of each segment of the bus line, and record the ratio of the difference to the total volatility characteristic index as the volatility weight.

[0038] Based on the fluctuation weight of each bus section, the remaining reactive power capacity of the reactive power compensation device of each bus section is weighted and summed to obtain the fluctuation-weighted remaining capacity.

[0039] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention is based on the voltage fluctuation characteristic index of each section of the substation bus in a set historical time period, and connects the corresponding reactive power compensation device to each section of the bus in combination with the type of reactive power compensation device, thereby reducing the waste of resources caused by connecting all bus sections with small fluctuation characteristic indices to large-capacity reactive power compensation devices, realizing the rational configuration of reactive power compensation devices, improving equipment utilization efficiency, and reducing costs.

[0040] (2) The present invention collects the measured voltage of each bus section to determine whether reactive power compensation is required. If reactive power compensation is required, the corresponding first reactive power compensation amount is calculated and output based on the voltage-reactive power sensitivity coefficient of each reactive power compensation device, so as to realize accurate initial compensation at the bus level, quickly suppress abnormal fluctuations in bus voltage, and ensure the voltage stability of a single bus section.

[0041] (3) This invention obtains the grid connection point power factor and reactive power of the current main transformer high voltage side, and judges whether the grid connection point power factor is qualified by combining the target power factor. When the power factor is not qualified, the active power of the grid connection point is obtained to calculate the total reactive power that the substation should compensate, so as to avoid problems such as low grid operation efficiency and power loss caused by the overall power factor not being qualified, and to ensure the coordinated operation of the substation and the upper-level grid.

[0042] (4) Based on the total reactive power compensation deficit and the remaining reactive power capacity of the reactive power compensation device of each bus section, this invention combines the fluctuation characteristic index of each bus section to calculate the fluctuation weight and the fluctuation weighted remaining capacity, and differentiates the second reactive power compensation amount of the corresponding reactive power compensation device, so that the compensation amount allocation is more reasonable, adapts to the overall compensation needs of the substation, and improves the overall reactive power compensation effect of the substation. Attached Figure Description

[0043] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the method steps of the present invention;

[0045] Figure 2 This is a schematic diagram illustrating the specific steps of the fluctuation characteristic index analysis method in this invention;

[0046] Figure 3 This is a schematic diagram of the steps in the analysis method for the second reactive power compensation quantity in this invention. Detailed Implementation

[0047] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. Furthermore, it should be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale.

[0048] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification.

[0049] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0050] Please see Figure 1 As shown, the present invention provides a reactive power compensation method for a power system substation, including: S1, distributing reactive power compensation devices to each section of the busbar.

[0051] Considering the differences in voltage fluctuation characteristics among different busbar sections, uniformly configuring reactive power compensation devices with the same rated capacity could lead to resource waste due to excessive compensation capacity for buses with low fluctuation characteristics. This would prevent precise matching between the reactive power compensation device and the busbar operating conditions, reducing equipment utilization efficiency and affecting the overall reactive power compensation effect. Therefore, quantitative analysis of the fluctuation characteristic index of each busbar section is used to reduce overall cost while meeting compensation requirements, aligning with the economic design principles of power engineering.

[0052] Furthermore, considering that the greater the voltage fluctuation amplitude and the higher the fluctuation frequency, the greater the demand for reactive power compensation, the weighted sum of the two can comprehensively reflect the overall fluctuation degree of the bus. The higher the index, the greater the comprehensive compensation demand of the bus. The bus is matched with the corresponding reactive power compensation device in descending order of the fluctuation characteristic index, so that the rated capacity of the reactive power compensation device is highly consistent with the actual reactive power compensation demand of the bus, and a reasonable allocation is achieved.

[0053] Based on this, in a specific embodiment of the present invention, the specific implementation steps of S1 are as follows: S11, Analyze the voltage fluctuation characteristic index of each section of the substation bus within a set historical time period. For example... Figure 2 As shown, the specific implementation steps are as follows: S111. Obtain the voltage of each section of busbar with the same voltage level in the power system substation within a set historical time period from the power system background database.

[0054] In this embodiment, a 10kV eight-segment busbar is used as an example, where the historical time period is set to the past month, but the implementer can also set other specific values.

[0055] S112. Calculate the voltage difference between each bus section and the rated bus voltage within a set historical time period to obtain the voltage difference at each time point, and form a voltage difference sequence.

[0056] S113. The ratio of the maximum absolute value of the voltage difference sequence of each bus segment to the rated bus voltage is denoted as the fluctuation amplitude factor. By calculating the ratio with the rated bus voltage, the normalized fluctuation amplitude factor is obtained.

[0057] S114. Based on the rated bus voltage, set the allowable voltage fluctuation range, count the number of times the voltage difference sequence of each bus segment exceeds the allowable fluctuation range, and calculate the fluctuation frequency factor of each bus segment by comparing it with the total time points of the set historical time period. Similarly, by comparing it with the total time points of the set historical time period, the fluctuation frequency factor is made to be within the range of [0, 1].

[0058] Furthermore, it should be noted that, in this field, the permissible voltage fluctuation range is typically set at 5% of the rated bus voltage. That is, when the voltage difference falls within this range, it is considered a normal fluctuation and no reactive power compensation is required. Implementers may set other specific percentages, but they should not exceed 5%.

[0059] S115. The volatility characteristic index is obtained by weighted summation of the volatility amplitude factor and volatility frequency factor of each bus line segment.

[0060] In this embodiment, considering that the larger the fluctuation amplitude, the higher the demand for compensation capacity, and that the fluctuation amplitude is the most important factor determining the reactive power compensation capacity demand of the bus, its impact on the compensation effect is more direct and significant than that of the fluctuation frequency, the weight of the fluctuation amplitude factor should be set higher than that of the fluctuation frequency factor. In this invention, the weight of the fluctuation amplitude factor is set to 70%, and the fluctuation frequency factor is set to 30%. Implementers can also set other weight allocations, but the sum of the two must be 1.

[0061] S12. Connect the corresponding reactive power compensation device to each bus section according to the type of reactive power compensation device. The specific steps are as follows: S121. Sort each bus section in descending order according to the fluctuation characteristic index. Based on the preset number of types of reactive power compensation devices, group the sorted buses to obtain each bus group.

[0062] In a preferred embodiment of the invention, two types of reactive power compensation devices with rated capacities of 10 Mvar and 15 Mvar are provided. Therefore, the sorted busbars are divided into two groups on average.

[0063] S122. Assign the reactive power compensation devices to each of the sorted bus groups in descending order of rated capacity, and connect all the busbars in each bus group to the reactive power compensation device of the corresponding assigned type. Specifically, connect all four busbar segments in the first group to a reactive power compensation device with a rated capacity of 15Mvar, and connect all four busbar segments in the second group to a reactive power compensation device with a rated capacity of 10Mvar.

[0064] This invention is based on the voltage fluctuation characteristic index of each bus section of a substation within a set historical time period. It combines the type of reactive power compensation device to connect the corresponding reactive power compensation device to each bus section, thereby reducing the resource waste caused by uniformly connecting large-capacity reactive power compensation devices to all bus sections with smaller fluctuation characteristic indices. This achieves the rational configuration of reactive power compensation devices, improves equipment utilization efficiency, and reduces costs.

[0065] S2. Calculate and output the first reactive power compensation amount of each reactive power compensation device based on the measured voltage of each bus section.

[0066] Considering that the real-time changes in bus voltage are a direct indicator of reactive power imbalance, and that different buses have different loads and operating conditions, resulting in different timing and degree of voltage anomalies, blindly compensating all buses in a uniform manner would cause the reactive power compensation device to operate ineffectively and create new voltage anomaly problems. Therefore, it is necessary to collect the measured voltage of each bus section in real time and determine the compensation requirement based on the voltage deviation.

[0067] Furthermore, considering the specific correlation between reactive power compensation and bus voltage changes, setting a fixed compensation amount outside this correlation would reduce the accuracy of compensation and fail to effectively suppress abnormal fluctuations in bus voltage. Therefore, it is necessary to analyze the voltage-reactive power sensitivity coefficients matched to each device to calculate an accurate initial reactive power compensation amount, thereby achieving targeted initial compensation at the bus level.

[0068] Based on this, the specific implementation steps of S2 are as follows: S21, collect the measured voltage of each bus section.

[0069] S22. Determine whether reactive power compensation is required. If reactive power compensation is required, calculate and output the corresponding first reactive power compensation amount based on the voltage-reactive power sensitivity coefficient of each reactive power compensation device. The specific implementation steps are as follows: S221. Calculate the current voltage difference by comparing the measured voltage of each bus section with the rated bus voltage.

[0070] S222. If the current voltage difference of a certain bus section is within the allowable voltage fluctuation range, it is determined that the bus section does not need reactive power compensation; otherwise, it is determined that reactive power compensation is required.

[0071] S223. When a busbar segment requires reactive power compensation, the current voltage difference of that busbar segment is compared with the corresponding voltage-reactive power sensitivity coefficient to obtain the first reactive power compensation amount of the reactive power compensation device corresponding to that busbar segment. In this embodiment, a negative reactive power compensation amount indicates that the reactive power compensation device needs to absorb inductive reactive power, and a positive reactive power compensation amount indicates that the reactive power compensation device needs to generate capacitive reactive power.

[0072] It should be noted that the method for obtaining the voltage-reactive power sensitivity coefficient includes: first, extracting the historical reactive power compensation records of each busbar's reactive power compensation device within a set historical time period from the power system's backend database.

[0073] Then, the inductive reactive power absorbed during each reactive power compensation process and the bus voltage change during each reactive power compensation are screened from the historical reactive power compensation records of each reactive power compensation device.

[0074] Next, the ratio of the bus voltage change to the absorbed inductive reactive power of each reactive power compensation device during each reactive power compensation process is calculated. After removing outliers, the average of the remaining ratios is recorded as the voltage-reactive power sensitivity coefficient of each reactive power compensation device.

[0075] For example, if the compensation amount in a certain compensation record is -10 Mvar, and the voltage drops by 1 kV, meaning it absorbed 10 Mvar of inductive reactive power, the voltage change is -1 kV, so the ratio is -0.1 kV / Mvar. The ratios for each reactive power compensation process are statistically analyzed, and the average and standard deviation are calculated. The sum of the average and three times the standard deviation is taken as the maximum value within the normal range, and the difference between the average and three times the standard deviation is taken as the minimum value within the normal range. These minimum and maximum values ​​form the normal range. All ratios outside the normal range are recorded as outliers and removed. The average of the remaining ratios after removing outliers is taken as the voltage-reactive power sensitivity coefficient for each reactive power compensation device.

[0076] This invention collects the measured voltage of each bus section to determine whether reactive power compensation is required. If reactive power compensation is required, it calculates and outputs the corresponding first reactive power compensation amount based on the voltage-reactive power sensitivity coefficient of each reactive power compensation device, thereby achieving accurate initial compensation at the bus level, quickly suppressing abnormal fluctuations in bus voltage, and ensuring voltage stability of a single bus section.

[0077] S3. Based on the current grid connection point power factor and target power factor of the main transformer high voltage side, calculate the total reactive power compensation required for the substation in combination with the active power at the grid connection point.

[0078] Considering that the reactive power compensation control of the substation not only needs to ensure the voltage stability of each bus section, but also needs to meet the global power factor control requirements of the main transformer high-voltage side grid connection point, ignoring the power factor of the main transformer high-voltage side grid connection point will reduce the overall operating efficiency of the power grid, increase line losses, and even cause economic losses related to power supply quality.

[0079] Furthermore, considering that determining the power factor requires considering the positional relationship between the current phase and the voltage phase, relying solely on the numerical value can easily lead to misjudgment, and the sign of reactive power directly reflects the positional relationship between the current phase and the voltage phase, it is necessary to combine the magnitude of the power factor and the sign of the current reactive power to determine whether it is qualified. If it is unqualified, the total reactive power compensation required by the substation should be calculated based on the active power at the grid connection point.

[0080] Based on this, the specific implementation steps of S3 are as follows: S31, obtain the grid connection point power factor and reactive power of the current main transformer high-voltage side, and determine whether the grid connection point power factor is qualified in combination with the target power factor. The grid connection point on the high-voltage side of the main transformer refers to the connection point between the high-voltage side of the main transformer and the upstream power grid. The power factor and reactive power at this point reflect the impact of the overall reactive power balance of the substation on the power grid.

[0081] Specifically, firstly, the target power factor and current reactive power of the grid connection point on the high-voltage side of the main transformer are extracted from the power system's backend database.

[0082] Next, if the current power factor at the grid connection point on the high-voltage side of the main transformer is greater than the target power factor and the current reactive power is greater than or equal to zero, then the current power factor is deemed to be qualified; otherwise, the current power factor is deemed to be unqualified.

[0083] When the current reactive power is greater than zero, it indicates that the system is under inductive load, and the current phase lags behind the voltage. When the current reactive power is less than zero, it indicates that the system is under capacitive load, and the current phase leads the voltage. When the current reactive power is equal to zero, the power factor is 1, which is the most ideal state.

[0084] Considering that if the current reactive power is less than zero, the current phase leads the voltage. In this case, the substation will send reactive power back to the grid, which will lead to voltage rise and line loss increase, violating the grid operation regulations. Therefore, when the current phase leads the voltage, even if the power factor at the grid connection point is greater than the target power factor, it is still judged as unqualified.

[0085] S32. When the power factor is unqualified, obtain the active power at the grid connection point to calculate the total reactive power to be compensated by the substation. The specific implementation steps are as follows: When the current power factor is unqualified, calculate the target reactive power based on the target power factor and the active power at the grid connection point, and record the difference between the target reactive power and the current reactive power as the total reactive power to be compensated.

[0086] The specific formula for calculating the target reactive power is as follows: .

[0087] in, Represents the target reactive power. Represents the active power at the grid connection point. This represents the power factor, and the formula is an existing formula for calculating reactive power, which will not be elaborated upon in this invention. If the current reactive power is less than zero, i.e., the current phase leads the voltage, then the calculated current reactive power will be... A negative value indicates that the system needs to absorb inductive reactive power for compensation; if the current reactive power is greater than zero, meaning the current phase lags behind the voltage, then... A positive number indicates that the system needs to issue capacitive reactive power for compensation.

[0088] For example, assuming the current power factor is 0.93, the current reactive power is -30Mvar, the current phase leads the voltage, the target power factor is 0.95, and the active power at the grid connection point is 50MW, then arccos(0.93) = 21.57°, the target reactive power is -19.75Mvar, that is, 19.75Mvar of inductive reactive power needs to be absorbed.

[0089] The power factor is the ratio of active power to apparent power, and the closer it is to 1, the better. In this embodiment, the target power factor at the grid connection point is 0.95 to improve energy efficiency and reduce losses, while retaining a buffer to prevent overcompensation.

[0090] This invention obtains the grid connection point power factor and reactive power of the current main transformer high-voltage side, and determines whether the grid connection point power factor is qualified by combining it with the target power factor. When the power factor is not qualified, the active power of the grid connection point is obtained to calculate the total reactive power that the substation should compensate, so as to avoid problems such as low grid operating efficiency and power loss caused by the overall unqualified power factor, and ensure the coordinated operation of the substation and the upper-level grid.

[0091] S4. Analyze the total reactive power compensation deficit based on the total reactive power compensation amount to be compensated in the substation and the first reactive power compensation amount of the reactive power compensation devices of each bus section. The method for obtaining the total reactive power compensation deficit is as follows: S41. Vector sum the first reactive power compensation amounts of the reactive power compensation devices of each bus section to record the total actual compensation amount. Considering the inductive and capacitive directional characteristics of reactive power, the vector sum refers to a signed algebraic sum.

[0092] S42. If the total actual compensation amount and the total reactive power compensation amount have the same sign, and the absolute value of the total actual compensation amount is greater than or equal to the absolute value of the total reactive power compensation amount, then the total reactive power compensation deficit is recorded as zero.

[0093] S43. Conversely, the difference between the total reactive power compensation amount and the total actual compensation amount is recorded as the total reactive power compensation deficit.

[0094] S5, the second reactive power compensation amount of the reactive power compensation device for each bus section.

[0095] Considering that the total reactive power compensation deficit is a comprehensive compensation requirement at the substation level, it needs to be supplemented by the remaining reactive power capacity of each bus reactive power compensation device. However, the remaining compensation capacity of different reactive power compensation devices varies due to the different first reactive power compensation amounts. If the deficit is simply divided equally according to the remaining reactive power capacity without taking into account the fluctuation characteristics of the bus itself, the remaining reactive power capacity of the reactive power compensation device of the bus with a high fluctuation characteristic index will be consumed too quickly, thereby weakening its ability to cope with subsequent voltage fluctuations.

[0096] Therefore, it is necessary to first accurately calculate the remaining reactive power capacity of each reactive power compensation device based on the positive and negative status of the total reactive power compensation deficit and the first reactive power compensation amount, and then perform weighted allocation in combination with the fluctuation characteristic index of each bus section, so that the second reactive power compensation amount can match the carrying capacity of the reactive power compensation device and conform to the working conditions of the bus, so as to achieve the accurate implementation of the overall compensation needs of the substation.

[0097] Based on this, the specific implementation steps of S5 in this embodiment are as follows: S51, based on the total reactive power compensation deficit and the remaining reactive power capacity of the reactive power compensation devices of each bus section. The specific steps are as follows: S511, when the first reactive power compensation amount of a certain reactive power compensation device is opposite in sign to the total reactive power compensation deficit, the rated capacity of the device is taken as the remaining reactive power capacity.

[0098] S512. When the first reactive power compensation amount of a certain reactive power compensation device has the same sign as the total reactive power compensation deficit, the difference between the rated capacity of the device and the absolute value of the first reactive power compensation amount is recorded as the remaining reactive power capacity. For example, if the current total reactive power compensation deficit is -10Mvar, the first reactive power compensation amount of a certain bus section is -3Mvar, and the rated capacity of that bus section is 10Mvar, then the remaining reactive power capacity is 7Mvar.

[0099] S52. Based on the fluctuation characteristic index of each bus section, allocate the second reactive power compensation amount of the corresponding reactive power compensation device. For example... Figure 3 As shown, in a specific embodiment of the present invention, the method for obtaining the second reactive power compensation amount includes: S521, comprehensively analyzing the fluctuation-weighted remaining capacity based on the remaining reactive power capacity of the reactive power compensation device of each bus segment combined with the fluctuation characteristic index. The specific analysis steps are as follows: S5211, calculating the sum of the fluctuation characteristic indices of each bus segment as the total fluctuation characteristic index, obtaining the difference between the total fluctuation characteristic index and the fluctuation characteristic index of each bus segment, and recording the ratio of this difference to the total fluctuation characteristic index as the fluctuation weight.

[0100] The fluctuation weight is calculated in the above way so that the calculated fluctuation weight is inversely proportional to the fluctuation characteristic index of each bus segment. That is, the bus segment with a larger fluctuation characteristic index receives a smaller fluctuation weight, and thus undertakes less compensation task in the subsequent second reactive power compensation allocation. This allows for more surplus reactive power capacity to cope with possible voltage fluctuations, extend equipment life, and improve the stability and reliability of system operation.

[0101] S5212. Based on the fluctuation weight of each bus section, the remaining reactive power capacity of the reactive power compensation device of each bus section is weighted and summed to obtain the fluctuation-weighted remaining capacity.

[0102] S522. The sum of the fluctuation-weighted residual capacity of the reactive power compensation devices of all buses is recorded as the total residual reactive power capacity.

[0103] S523. The ratio of the fluctuation-weighted residual capacity of the reactive power compensation device of each bus section to the total residual reactive power capacity is recorded as the allocation ratio.

[0104] S524. Calculate the corresponding second reactive power compensation amount by multiplying the distribution ratio of the reactive power compensation device of each bus section with the total reactive power compensation deficit.

[0105] S53. Control the reactive power compensation device of each bus section to output the corresponding second reactive power compensation amount.

[0106] This invention is based on the total reactive power compensation deficit and the remaining reactive power capacity of the reactive power compensation devices of each bus section. By combining the fluctuation characteristic index of each bus section and calculating the fluctuation weight and fluctuation-weighted remaining capacity, the second reactive power compensation amount of the corresponding reactive power compensation device is allocated in a differentiated manner, making the compensation amount allocation more reasonable, adapting to the overall compensation needs of the substation, and improving the overall reactive power compensation effect of the substation.

[0107] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0108] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0109] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0110] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0111] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A reactive power compensation method for a power system substation, characterized in that, include: Based on the voltage fluctuation characteristic index of each bus section of the substation within a set historical time period, and combined with the type of reactive power compensation device, the corresponding reactive power compensation device is connected to each bus section. Collect the measured voltage of each bus section to determine whether reactive power compensation is required. If reactive power compensation is required, calculate and output the corresponding first reactive power compensation amount based on the voltage-reactive power sensitivity coefficient of each reactive power compensation device. Obtain the current grid connection point power factor and reactive power on the high voltage side of the main transformer. Combine the target power factor to determine whether the grid connection point power factor is qualified. When the power factor is not qualified, obtain the grid connection point active power and calculate the total reactive power that the substation should compensate. The total reactive power compensation deficit is analyzed based on the total reactive power compensation amount of the substation and the first reactive power compensation amount of the reactive power compensation device of each bus section. Based on the total reactive power compensation deficit and the remaining reactive power capacity of the reactive power compensation devices of each bus section, the second reactive power compensation amount of the corresponding reactive power compensation device is allocated in combination with the fluctuation characteristic index of each bus section, and the corresponding second reactive power compensation amount is output.

2. The reactive power compensation method for a power system substation according to claim 1, characterized in that, The analysis method for the volatility characteristic index is as follows: Obtain the voltage of each bus section with the same voltage level within a substation of the power system from the power system's backend database within a set historical time period; The voltage difference at each time point is calculated by comparing the voltage of each bus section with the rated bus voltage within a set historical time period, and a voltage difference sequence is formed. The ratio of the maximum absolute value of the voltage difference sequence of each bus segment to the rated bus voltage is denoted as the fluctuation amplitude factor. Based on the rated bus voltage, the allowable voltage fluctuation range is set, and the number of times the voltage difference sequence of each bus section exceeds the allowable fluctuation range is counted. The fluctuation frequency factor of each bus section is calculated by comparing the number of times the voltage difference sequence exceeds the allowable fluctuation range with the total time points of the set historical time period. The volatility characteristic index is obtained by weighting and summing the volatility amplitude factor and volatility frequency factor of each bus line segment.

3. The reactive power compensation method for a power system substation according to claim 1, characterized in that, The connection method of the reactive power compensation device is as follows: The busbars are sorted in descending order according to the fluctuation characteristic index. Based on the preset type and number of reactive power compensation devices, the sorted busbars are grouped to obtain each busbar group. The reactive power compensation devices are assigned to each bus group in descending order of rated capacity, and all buses in each bus group are connected to the reactive power compensation device of the corresponding assigned type.

4. The reactive power compensation method for a power system substation according to claim 2, characterized in that, The analysis method for the first reactive power compensation is as follows: The current voltage difference is calculated by comparing the measured voltage of each busbar segment with the rated busbar voltage. If the current voltage difference of a certain bus section is within the allowable voltage fluctuation range, it is determined that the bus section does not need reactive power compensation; otherwise, it is determined that reactive power compensation is required. When a busbar section needs reactive power compensation, the ratio of the current voltage difference of the busbar section to the corresponding voltage-reactive power sensitivity coefficient is analyzed to obtain the first reactive power compensation amount of the reactive power compensation device corresponding to the busbar section.

5. A reactive power compensation method for a power system substation according to claim 4, characterized in that, The method for obtaining the voltage-reactive power sensitivity coefficient includes: Extract historical reactive power compensation records of each busbar section's reactive power compensation device within a set historical time period from the power system's backend database. The inductive reactive power absorbed during each reactive power compensation process and the bus voltage change during each reactive power compensation were screened from the historical reactive power compensation records of each reactive power compensation device. The ratio of the bus voltage change to the absorbed inductive reactive power of each reactive power compensation device during each reactive power compensation process is statistically analyzed. After removing outliers, the average of the remaining ratios is recorded as the voltage-reactive power sensitivity coefficient of each reactive power compensation device.

6. The reactive power compensation method for a power system substation according to claim 1, characterized in that, The method for obtaining the total reactive power to be compensated includes: Extract the target power factor and current reactive power of the grid connection point on the high-voltage side of the main transformer from the power system's back-end database; If the current power factor at the grid connection point on the high-voltage side of the main transformer is greater than the target power factor and the current reactive power is greater than or equal to zero, then the current power factor is deemed to be qualified; otherwise, the current power factor is deemed to be unqualified. When the current power factor is not up to standard, the target reactive power is calculated based on the target power factor and the active power at the grid connection point, and the difference between the target reactive power and the current reactive power is recorded as the total reactive power to be compensated.

7. A reactive power compensation method for a power system substation according to claim 6, characterized in that, The method for obtaining the total reactive power compensation deficit is as follows: The first reactive power compensation amount of the reactive power compensation device of each bus section is vector-summed and recorded as the total actual compensation amount. If the total actual compensation amount and the total reactive power compensation amount have the same sign, and the absolute value of the total actual compensation amount is greater than or equal to the absolute value of the total reactive power compensation amount, then the total reactive power compensation deficit is recorded as zero. Conversely, the difference between the total reactive power compensation amount and the total actual compensation amount is recorded as the total reactive power compensation deficit.

8. A reactive power compensation method for a power system substation according to claim 7, characterized in that, The method for obtaining the remaining reactive power capacity includes: When the first reactive power compensation amount of a certain reactive power compensation device is opposite in sign to the total reactive power compensation deficit, the rated capacity of the device shall be taken as the remaining reactive power capacity. When the first reactive power compensation amount of a certain reactive power compensation device has the same sign as the total reactive power compensation deficit, the difference between the rated capacity of the device and the absolute value of the first reactive power compensation amount is recorded as the remaining reactive power capacity.

9. A reactive power compensation method for a power system substation according to claim 1, characterized in that, The method for obtaining the second reactive power compensation amount includes: The remaining reactive capacity of the reactive power compensation device for each bus section is combined with the fluctuation characteristic index to comprehensively analyze the fluctuation-weighted remaining capacity. The sum of the fluctuation-weighted residual capacity of the reactive power compensation devices of all buses is recorded as the total residual reactive power capacity; The ratio of the fluctuation-weighted residual capacity of the reactive power compensation device of each bus section to the total residual reactive power capacity is recorded as the allocation ratio. The corresponding second reactive power compensation amount is obtained by multiplying the distribution ratio of the reactive power compensation device of each bus section with the total reactive power compensation deficit.

10. A reactive power compensation method for a power system substation according to claim 9, characterized in that, The analysis method for the fluctuation-weighted residual capacity is as follows: The sum of the volatility characteristic indices of each segment of the bus line is calculated and denoted as the total volatility characteristic index. The difference between the total volatility characteristic index and the volatility characteristic index of each segment of the bus line is obtained, and the ratio of the difference to the total volatility characteristic index is denoted as the volatility weight. Based on the fluctuation weight of each bus section, the remaining reactive power capacity of the reactive power compensation device of each bus section is weighted and summed to obtain the fluctuation-weighted remaining capacity.

Images