A method and device for grid-based regional collaborative comprehensive management of power quality in low-voltage distribution station areas

Abstract

The present invention discloses a method and device for grid-based regional coordinated comprehensive management of power quality in a low-voltage distribution station area, and specifically relates to the technical field of power quality management, including implementing a three-phase balancing strategy based on power consumption status information of all nodes in the low-voltage distribution station area, obtaining an optimal scheduling instruction sequence, performing phase switching operations on each node in the station area according to the optimal scheduling instruction sequence, obtaining operation information and power quality information during the implementation of the three-phase balancing strategy, and evaluating the performance of power quality in the station area after the station area uses the three-phase balancing strategy. If the implementation of the optimal scheduling instruction sequence still cannot solve the three-phase imbalance problem, a voltage-reactive comprehensive control method is implemented. After the voltage-reactive comprehensive control method is executed for regulation, the performance of the station area after regulation by the voltage-reactive comprehensive control method is quantified. The present invention helps to improve the power quality of three-phase imbalance and improve the overall stability and power quality of the power grid.

Description

Technical Field

[0001] The present invention relates to the technical field of power quality management, and more specifically, to a method and device for coordinated comprehensive management of power quality in a grid-based area in a low-voltage distribution station area. Background Art

[0002] With the rapid growth of electricity demand and the widespread application of modern power equipment, power quality issues have become an important challenge in power supply area management. The quality of power directly affects the operation of power users' equipment and the overall stability of the power system. It not only causes damage or malfunction of power users' equipment, but also affects the operating efficiency and safety of the power system.

[0003] The power supply substation is the end of the power system and directly provides electricity to users. The power quality is crucial to the normal operation of user equipment. With the access of distributed power sources, renewable energy (such as photovoltaic and wind power) and electric vehicle charging facilities, the power quality of the power supply substation faces greater challenges:

[0004] These include three-phase imbalance, insufficient reactive power compensation, reactive voltage problems caused by line loss, etc. Power quality problems can be solved by dynamic reactive power compensation devices, three-phase imbalance adjustment devices and voltage regulators, but their scope of action is relatively narrow, and there is a lack of a comprehensive and effective global control strategy to control the overall power supply quality from the level of the entire substation.

[0005] In order to solve the above defects, a technical solution is now provided. Summary of the invention

[0006] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a method and device for grid-based regional collaborative comprehensive management of power quality in a low-voltage distribution station area to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A method for grid-based regional coordinated comprehensive management of power quality in a low-voltage distribution station area comprises the following steps:

[0009] S1: The LoRa wireless module cyclically collects the power consumption status information of each node, and determines the power consumption status information of all nodes in the low-voltage distribution station area to implement a three-phase balance strategy;

[0010] S2: The optimal dispatching instruction sequence is obtained through the differential evolution algorithm in the three-phase balancing strategy. According to the optimal dispatching instruction sequence, the phase switching operation is performed on each node in the substation area, and the operation information and power quality information in the process of implementing the three-phase balancing strategy are obtained;

[0011] S3: Evaluate the performance of power quality in the substation after using the three-phase balance strategy. If the implementation of the optimal dispatch instruction sequence still cannot solve the three-phase imbalance problem, priority will be given to performing reactive power compensation or adjusting the voltage of each node, and generating an abnormal communication signal;

[0012] S4: According to the time when the abnormal communication signal appears, the voltage and reactive power integrated control method is implemented, and the status of each node in the control background area is collected to obtain the power risk information;

[0013] S5: Based on the power risk information, a control risk assessment model is constructed to generate a control risk assessment coefficient, and the performance of the control background area after being controlled by the voltage and reactive power integrated control method is quantified;

[0014] Among them, by analyzing the operation information and power quality information, a differential deviation coefficient and a node balance abnormality coefficient are generated, and the logic for obtaining the differential deviation coefficient is: by using the differential evolution algorithm on the low-voltage distribution station area, the dispatching instruction of the final low-voltage distribution station area is obtained, the number of phase changes performed in the low-voltage distribution station area and the final three-phase imbalance are determined, and the number of phase changes performed in the low-voltage distribution station area and the final three-phase imbalance are marked as: HX and PH respectively;

[0015] Set the commutation number threshold and the three-phase imbalance threshold, take the ratio of the commutation number threshold to the commutation number in the low-voltage distribution station area as the commutation number deviation, and take the ratio of the three-phase imbalance threshold to the final three-phase imbalance in the low-voltage distribution station area as the three-phase imbalance deviation;

[0016] Calculate the differential deviation coefficient using the formula: Among them, CF pc is the differential deviation coefficient, HX pc is the commutation frequency deviation, SX pc is the three-phase unbalance deviation;

[0017] The logic for obtaining the node balance abnormality coefficient is: obtaining the three-phase imbalance of each node in the low-voltage distribution substation after the differential evolution algorithm is used, and marking the three-phase imbalance of each node in the low-voltage distribution substation after the differential evolution algorithm is used as: PH n , where n = 1, 2, 3, ..., N, N is a positive integer, and n is the number of each node in the low-voltage distribution station area;

[0018] The average value and standard deviation of the three-phase imbalance of each node are obtained, and the average value and standard deviation of the three-phase imbalance of each node are marked as: PH avg and PH std ,in,

[0019] Calculate the coefficient of variation of the three-phase unbalance degree of each node, and mark the coefficient of variation of the three-phase unbalance degree of each node as:

[0020] Calculate the node balance abnormality coefficient, the calculation formula is: Among them, YC ph is the node balance abnormality coefficient.

[0021] In a preferred embodiment, a three-phase balancing strategy is implemented, including:

[0022] According to the three-phase load data of the substation transformer collected at the current headend, the moment when the three-phase load imbalance exceeds the limit is determined, and a scheduling instruction sequence is generated through the differential evolution algorithm. It is then sent to each node through LoRa, and the node executes the load scheduling instruction. The scheduling instruction sequence includes the number of phase changes, the phase change load of the node, and the final three-phase imbalance of the substation.

[0023] In a preferred embodiment, evaluating the performance of power quality in the back-end area after the back-end area uses the three-phase balancing strategy includes:

[0024] The differential deviation coefficient and the node balance abnormality coefficient are comprehensively analyzed to establish a balance strategy evaluation model and generate a balance strategy evaluation coefficient. The expression of the balance strategy evaluation coefficient is: pg cl =β 1 CF pc +β 2 BY ph , where pg cl is the balance strategy evaluation coefficient, β 1 , β 2 are the proportional coefficients of the differential deviation coefficient and the node balance abnormality coefficient, β 1 , β 2 They are both greater than 0;

[0025] Set a balance strategy evaluation coefficient threshold, and compare the balance strategy evaluation coefficient threshold with the balance strategy evaluation coefficient;

[0026] If the balance strategy evaluation coefficient threshold is greater than the balance strategy evaluation coefficient, the three-phase balance strategy is executed according to the scheduling instruction sequence generated by the differential evolution algorithm;

[0027] If the balancing strategy evaluation coefficient threshold is less than the balancing strategy evaluation coefficient, an abnormal communication signal is generated, and the three-phase balancing strategy cannot be executed according to the scheduling instruction sequence generated by the differential evolution algorithm. Priority is given to executing reactive power compensation or adjusting the voltage of each node.

[0028] In a preferred embodiment, according to the time when the abnormal communication signal appears, a voltage and reactive power integrated control method is implemented, including:

[0029] When the communication with all other nodes is abnormal, the host will regulate the on-load voltage regulation and distribution transformer and reactive power compensation device at the head end in an orderly manner according to the head end voltage and reactive power status data collected by itself and the new nine-domain diagram, thus realizing the comprehensive control of voltage and reactive power based on the new nine-domain strategy.

[0030] When at least one child node is communicating normally, the real-time status data of all nodes communicating normally are comprehensively considered, and a reactive power and voltage management strategy is adopted. First, the reactive power of the current head end is compensated to the maximum extent, and the control target is to minimize the reactive power of the head end and avoid over-compensation.

[0031] Secondly, for the regulation of the on-load voltage regulation and distribution transformer gear position, the host will traverse all possible gear position changes ΔL of the current transformer, and estimate the voltage value of each node after the gear adjustment, and then count the number of qualified nodes C among all nodes and cache them;

[0032] After the traversal is completed, the ΔL that makes C reach the maximum value is extracted as the adjustment target. Therefore, the basis for adjustment is the voltage data of all current nodes, and the control target is to maximize the number of qualified nodes.

[0033] In a preferred embodiment, the electric energy risk information includes:

[0034] The power quality of the low-voltage distribution station area is regulated, the status of the head-end voltage and reactive power after regulation is collected, and the status of each node in the back-end area after regulation is collected to obtain power risk information, which is represented by the head-end power safety concealment coefficient and the node impact risk assessment coefficient.

[0035] In a preferred embodiment, the logic for obtaining the electric energy safety concealment coefficient is:

[0036] Obtain the performance of the head-end voltage and reactive power in the monitoring interval after regulation, collect the head-end voltage in the monitoring interval, and mark the head-end voltage in the monitoring interval as: V i , where i = 1, 2, 3, ..., I, I is a positive integer, i is the number of each head-end power source collected during the monitoring period, the reactive power in the monitoring interval is collected, and the head-end reactive power in the monitoring interval is marked as: Q i ;

[0037] Set the operating range of the first-end voltage and mark the operating range of the first-end voltage as: V min ~V max , set the reactive power threshold at the first end, and mark the reactive power threshold at the first end as: Q YZ ;

[0038] The collected head-end voltage within the monitoring interval is compared with the operating range of the head-end voltage to obtain the head-end power supply that is not within the operating range of the head-end voltage within the monitoring interval, and the head-end power supply that is not within the operating range of the head-end voltage is re-marked as: V k , where k=1, 2, 3, ..., K, K is a positive integer, and k is the number of the head-end power supply that is not within the operating range of the head-end voltage;

[0039] Calculate the voltage safety concealment coefficient, the calculation formula is: Among them, DY aq is the voltage safety concealment factor;

[0040] The collected head-end reactive power in the monitoring interval is compared with the head-end reactive power threshold, and the head-end reactive power greater than the head-end reactive power threshold in the monitoring interval is obtained, and the head-end reactive power greater than the head-end reactive power threshold is re-marked as: Q p , where p=1, 2, 3, ..., P, P is a positive integer, and p is the serial number of the head-end reactive power that is greater than the head-end reactive power threshold;

[0041] Calculate the reactive power safety concealment coefficient, the calculation formula is: Among them, GL aq is the reactive power safety concealment factor;

[0042] Calculate the power safety concealment coefficient, the calculation formula is: DN aq =(DY aq ×GL aq ) P+K ; Among them, the power safety concealment factor is DN aq .

[0043] The logic for obtaining the node impact risk assessment coefficient is as follows: obtaining nodes of various types in the low-voltage distribution substation area, based on the current power quality data of nodes of various types in the low-voltage distribution substation area, combining the power quality problems and the impact of power quality that appear in the current power quality data of nodes of various types in the historical data, scoring nodes of different types by the expert equal weight principle, and determining the impact score values ​​of nodes of different types;

[0044] A regression model is constructed based on the proportion of each type of node in the low-voltage distribution substation area and the impact score of different types of nodes to obtain the node impact risk assessment coefficient. The expression of the node impact risk assessment coefficient is: Among them, JD yx is the node impact risk assessment coefficient, YX 1 , YX 2 , YX 3 ,……,YX jis the impact score of different types of nodes, SL 1 , SL 2 , SL 3 ,……,SL j is the proportion of the number of nodes of each type, j = 1, 2, 3, ..., J, J is a positive integer, and j is the number of nodes of each type in the current low-voltage distribution station area;

[0045] The logic for obtaining the proportion of each type of node is as follows: obtain the number of nodes in the current low-voltage distribution substation, obtain the node type in the current low-voltage distribution substation, and the calculation formula for the proportion of each type of node is as follows: Among them, LX j is the number of node types in the current low-voltage distribution station area, and e is a natural number.

[0046] In a preferred embodiment, the performance of the background area after being regulated by the voltage and reactive power integrated control method after being quantified and regulated includes:

[0047] The head-end power safety concealment coefficient and the node impact risk assessment coefficient are weighted and calculated to construct a control risk assessment model to generate a control risk assessment coefficient. The calculation formula of the control risk assessment coefficient is: Among them, PG tk is the control risk assessment coefficient, ε 1 , ε 2 is the proportional coefficient of the head-end power safety concealment coefficient and the node impact risk assessment coefficient, ε 1 , ε 2 They are both greater than 0;

[0048] Set a control risk assessment coefficient threshold, and compare the control risk assessment coefficient with the control risk assessment coefficient threshold;

[0049] If the control risk assessment coefficient is greater than the control risk assessment coefficient threshold, a warning signal is generated;

[0050] If the regulation risk assessment coefficient is less than the regulation risk assessment coefficient threshold, no warning signal is generated. By monitoring the moment when the three-phase load imbalance in the substation exceeds the limit, the above steps are repeated to achieve comprehensive voltage and reactive power control.

[0051] In a preferred embodiment, a low-voltage distribution station area power quality grid-based regional collaborative comprehensive management device is used to implement a low-voltage distribution station area power quality grid-based regional collaborative comprehensive management method.

[0052] Technical effects and advantages of the present invention:

[0053] 1. The present invention innovatively introduces a differential evolution algorithm to obtain the optimal phase-changing combination in the treatment of three-phase load imbalance, and at the same time takes the final imbalance and the number of phase changes into consideration, striving to obtain a relatively better phase-changing combination with fewer phase changes, which helps to improve the power quality of three-phase imbalance and improve the overall stability and power quality of the power grid;

[0054] 2. The present invention provides two methods for comprehensive control of voltage and reactive power in the substation when communication between substation nodes is abnormal. The system also quantifies the performance of the substation after being regulated by the voltage and reactive power comprehensive control method by monitoring the power quality data of the head end and other nodes in the substation. That is, when the power quality after regulation still does not meet the standard, the system will issue an early warning in time to remind the operation and maintenance personnel to take further measures to avoid power grid failure or equipment damage, which helps to maintain stable operation of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to facilitate understanding by those skilled in the art, the present invention is further described below in conjunction with the accompanying drawings;

[0056] Figure 1 It is a flow chart of a method for grid-based regional collaborative comprehensive management of power quality in a low-voltage distribution station area according to the present invention;

[0057] Figure 2 The present invention provides the details of the reactive voltage control strategy at the head end of the substation based on the new nine-domain strategy. DETAILED DESCRIPTION

[0058] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0059] Example 1

[0060] Figure 1 A schematic flow chart of a method for grid-based regional coordinated comprehensive management of power quality in a low-voltage distribution station area is provided in the present invention, which specifically includes the following steps:

[0061] S1: The LoRa wireless module cyclically collects the power consumption status information of each node, and determines the power consumption status information of all nodes in the low-voltage distribution station area to implement a three-phase balance strategy;

[0062] S2: The optimal dispatching instruction sequence is obtained through the differential evolution algorithm in the three-phase balancing strategy. According to the optimal dispatching instruction sequence, the phase switching operation is performed on each node in the substation area, and the operation information and power quality information in the process of implementing the three-phase balancing strategy are obtained;

[0063] S3: Evaluate the performance of power quality in the substation after using the three-phase balance strategy. If the implementation of the optimal dispatch instruction sequence still cannot solve the three-phase imbalance problem, priority will be given to performing reactive power compensation or adjusting the voltage of each node, and generating an abnormal communication signal;

[0064] S4: According to the time when the abnormal communication signal appears, the voltage and reactive power integrated control method is implemented, and the status of each node in the control background area is collected to obtain the power risk information;

[0065] S5: Based on the power risk information, a control risk assessment model is constructed to generate a control risk assessment coefficient to quantify the performance of the background area after being controlled by the voltage and reactive power integrated control method.

[0066] Identify and record all key equipment and power consumption points related to power distribution in the low-voltage distribution station area, and treat all key equipment and power consumption points as nodes in the low-voltage distribution station area. Nodes that are only dispatched by the station area are divided into the same grid, and nodes that are dispatched by multiple stations are regarded as edges or vertices of the grid.

[0067] It should be noted that nodes that are uniquely scheduled by a substation are completely under the scheduling control of one substation. They can be divided into specific grids for centralized management and optimization. Nodes that are scheduled by multiple substations are affected by multiple substations. They usually serve as the boundaries or vertices of the grid and play a key role in cross-grid scheduling and optimization.

[0068] The LoRa wireless module cyclically collects the power consumption status information of each node and integrates the power consumption information of each node into the central computer. The central computer is a computer or server responsible for running control algorithms, optimization strategies and data analysis, and is responsible for comprehensive management and control of the equipment or system of the distribution network.

[0069] Among them, the LoRa wireless module is a technology for long-distance, low-power wireless communication, mainly used in Internet of Things (IoT) applications. The LoRa module can transmit data over a wide range of distances and is suitable for applications that require long-distance communication;

[0070] The host is connected to the on-load voltage-changing distribution transformer controller and intelligent compensation capacitor through the RS485 bus, interacts with the devices deployed at other nodes in the substation through the Lora wireless module, and implements control strategies based on the operating status of the above nodes to achieve comprehensive management of the power quality of the power supply substation.

[0071] The power consumption status information is collected through the intelligent load dispatching circuit breaker, the integrated reactive power compensation device and the wall-mounted single-phase voltage regulator. The intelligent load dispatching circuit breaker is used to collect the node voltage, load current, load working phase, terminal temperature and phase switching times;

[0072] The integrated reactive power compensation device is used to collect node voltage, active power, reactive power and apparent power;

[0073] The wall-mounted single-phase voltage regulator is used to collect node voltage and load current.

[0074] According to the three-phase load data of the substation transformer collected at the current headend, the moment when the three-phase load imbalance exceeds the limit is determined, and a scheduling instruction sequence is generated through the differential evolution algorithm. It is then sent to each node through LoRa, and the node executes the load scheduling instruction. The scheduling instruction sequence includes the number of phase changes, the phase change load of the node, and the final three-phase imbalance of the substation.

[0075] The number of phase changes refers to the number of inter-phase load transfer operations performed in the entire scheduling process to reduce the three-phase imbalance. Each phase change means transferring the load of a node from one phase to another. More phase changes can usually optimize the three-phase load balance more finely, but too many phase changes will increase scheduling complexity and system overhead. Therefore, the relationship between the number of phase changes and the load balance should be balanced during optimization.

[0076] The commutation load of a node refers to the load that needs to be adjusted during the commutation process of each node. The commutation load determines how the node load is distributed between different phases to reduce the imbalance.

[0077] The final three-phase imbalance of the substation refers to the final three-phase load imbalance of the entire substation after executing the dispatch instruction. This is a key indicator for evaluating the dispatch effect and indicates the degree of balance of the three-phase load after adjustment.

[0078] During the implementation of the differential evolution algorithm, the population size is set to 500, the number of individuals is 1, the scaling factor is 0.5, the crossover probability is 0.8, the number of iterations is 500, and the objective function is defined. The formula of the objective function is: f(C, ubr) = α 1 C+α 2 ubr, where f(C, ubr) is the objective function of the differential evolution algorithm, C is the number of commutation times, ubr is the final three-phase imbalance, and α 1 , α 2 are the proportional coefficients of the number of commutation and the final three-phase imbalance, α 1 , α 2 are greater than 0, α 1 +α 2 =1, the proportional coefficient between the number of commutation times and the final three-phase imbalance is set by professionals, usually α 1 is 0.7, α 2 is 0.3. Through the mutation, crossover and selection of the differential evolution algorithm, the optimal scheduling instruction sequence is obtained based on minimizing the objective function.

[0079] It should be noted that the differential evolution algorithm can optimize multiple objectives at the same time. For power load scheduling, it may be necessary to consider multiple objectives at the same time, such as minimizing load imbalance and reducing the number of phase changes. The DE algorithm can find a balance between these objectives and generate a comprehensive optimization solution.

[0080] By performing phase switching operations within the substation, the load distribution between nodes is adjusted, thereby affecting the power balance of each node and reducing the three-phase imbalance.

[0081] According to the optimal scheduling instruction sequence of the differential evolution algorithm, the operation information and power quality information performed in the low-voltage distribution station area are obtained, wherein the operation information includes the number of phase changes of each node, and the power quality information includes the three-phase imbalance of each node. By analyzing the operation information and power quality information, the differential deviation coefficient and the node balance abnormality coefficient are generated.

[0082] The acquisition logic of the differential deviation coefficient is: by using the differential evolution algorithm on the low-voltage distribution substation, the dispatch instruction of the final low-voltage distribution substation is obtained, the number of phase changes performed in the low-voltage distribution substation and the final three-phase imbalance are determined, and the number of phase changes performed in the low-voltage distribution substation and the final three-phase imbalance are marked as: HX and PH respectively;

[0083] Set the commutation number threshold and the three-phase imbalance threshold, take the ratio of the commutation number threshold to the commutation number in the low-voltage distribution station area as the commutation number deviation, and take the ratio of the three-phase imbalance threshold to the final three-phase imbalance in the low-voltage distribution station area as the three-phase imbalance deviation;

[0084] It should be noted that the commutation number threshold and the three-phase imbalance threshold are set by professional staff. The differential evolution algorithm can be used to obtain the commutation number and the final three-phase imbalance of the low-voltage distribution station. If the commutation number and the final three-phase imbalance of the low-voltage distribution station are much smaller than the commutation number threshold and the three-phase imbalance threshold, it means that the station can use the differential evolution algorithm to execute the three-phase balance strategy to avoid excessive three-phase load imbalance.

[0085] Calculate the differential deviation coefficient using the formula: Among them, CF pc is the differential deviation coefficient, HX pc is the commutation frequency deviation, SX pc It is the three-phase unbalance deviation.

[0086] It can be seen from the formula that the larger the differential deviation coefficient is, the higher the number of phase changes and the final three-phase imbalance obtained by the differential evolution algorithm may be, which is not conducive to the implementation of the three-phase balance strategy. It means that insufficient compensation of reactive power in the system may cause the load imbalance to be unable to be effectively improved by phase change, or some nodes have long-term low voltage problems, which may lead to load imbalance and phase change operation may not be able to effectively improve voltage distribution.

[0087] The logic for obtaining the node balance abnormality coefficient is: obtaining the three-phase imbalance of each node in the low-voltage distribution substation after the differential evolution algorithm is used, and marking the three-phase imbalance of each node in the low-voltage distribution substation after the differential evolution algorithm is used as: PH n , where n = 1, 2, 3, ..., N, N is a positive integer, and n is the number of each node in the low-voltage distribution station area;

[0088] The average value and standard deviation of the three-phase imbalance of each node are obtained, and the average value and standard deviation of the three-phase imbalance of each node are marked as: PH avg and PH std ,in,

[0089] Calculate the coefficient of variation of the three-phase unbalance degree of each node, and mark the coefficient of variation of the three-phase unbalance degree of each node as:

[0090] Calculate the node balance abnormality coefficient, the calculation formula is: Among them, YC ph is the node balance abnormality coefficient.

[0091] It can be seen from the formula that the larger the node balance abnormality coefficient is, the greater the difference in node load imbalance within the substation area is, which may have a negative impact on the operation and stability of the power system. The following are the specific impacts:

[0092] Voltage fluctuations: Load imbalance with large standard deviation may lead to increased voltage fluctuations, especially when the load changes drastically. Such fluctuations may affect the normal operation of electrical equipment and may cause equipment damage;

[0093] Increased line losses: Unbalanced loads will lead to uneven current distribution on the line, which will increase line losses. This will lead to lower power transmission efficiency, increased energy waste and operating costs;

[0094] Reduced system stability: Large load imbalances can affect the overall stability of the power system and increase the risk of system failures, especially during high load and demand situations.

[0095] The differential deviation coefficient and the node balance abnormality coefficient are comprehensively analyzed to establish a balance strategy evaluation model and generate a balance strategy evaluation coefficient. The expression of the balance strategy evaluation coefficient is: pg cl =β 1 CF pc +β 2 BY ph , where pg cl is the balance strategy evaluation coefficient, β 1 , β 2 are the proportional coefficients of the differential deviation coefficient and the node balance abnormality coefficient, β 1 , β 2 Both are greater than 0.

[0096] Set the balancing strategy evaluation coefficient threshold. The balancing strategy evaluation coefficient threshold is used to measure whether the substation can use the scheduling instruction sequence generated by the differential evolution algorithm to schedule each node in the substation. Compare the balancing strategy evaluation coefficient threshold with the balancing strategy evaluation coefficient. If the balancing strategy evaluation coefficient threshold is greater than the balancing strategy evaluation coefficient, the three-phase balancing strategy is executed according to the scheduling instruction sequence generated by the differential evolution algorithm. If the balancing strategy evaluation coefficient threshold is less than the balancing strategy evaluation coefficient, an abnormal communication signal is generated, and the three-phase balancing strategy cannot be executed according to the scheduling instruction sequence generated by the differential evolution algorithm. Priority is given to executing reactive power compensation or adjusting the voltage of each node.

[0097] This embodiment innovatively introduces a differential evolution algorithm to obtain the optimal phase-changing combination in the management of three-phase load imbalance, and at the same time takes the final imbalance degree and the number of phase changes into consideration, striving to obtain a relatively better phase-changing combination with fewer phase changes, which helps to improve the power quality of three-phase imbalance and improve the overall stability and power quality of the power grid.

[0098] Example 2

[0099] The above embodiment introduces a differential evolution algorithm to obtain the optimal commutation combination. However, when the scheduling instruction sequence generated by the differential evolution algorithm is impractical or cannot meet the power quality requirements, the power quality of the low-voltage distribution station area is controlled by considering reactive power compensation and adjusting the output voltage.

[0100] According to the moment when the abnormal communication signal appears, the voltage and reactive power comprehensive control method is implemented, including scanning the communication status of all nodes, and the next step of regulation is carried out according to the communication status of all nodes into two situations, specifically:

[0101] When the communication with all other nodes is abnormal (communication timeout), the host will regulate the on-load voltage regulation and distribution transformer and reactive power compensation device at the head end in an orderly manner according to the head end voltage and reactive power status data collected by itself and the new nine-domain diagram, thereby realizing comprehensive control of voltage and reactive power based on the new nine-domain strategy.

[0102] Among them, Figure 2 The following are the details of the reactive voltage control strategy for the head end of the substation area based on the new nine-domain strategy of the present invention, which specifically include:

[0103] Zone 6: The current zone is operating normally and no adjustments are made;

[0104] Zone 1: Reactive power exceeds the lower limit and voltage exceeds the upper limit, capacitors are cut off and taps are lowered;

[0105] Zone 2: The voltage exceeds the upper limit, cut off the capacitor and lower the tap;

[0106] Zone 3: Reactive power approaches the upper limit and voltage exceeds the upper limit, and the tap is lowered;

[0107] Zone 4: Reactive power exceeds the upper limit and voltage exceeds the upper limit, lower the tap and add capacitors;

[0108] Zone 5: Reactive power exceeds the lower limit, capacitors are cut off and taps are lowered;

[0109] Zone 7: Reactive power exceeds the upper limit and voltage approaches the upper limit, lower the tap and put capacitors into operation;

[0110] Zone 8: Reactive power exceeds the lower limit and voltage approaches the lower limit, capacitors are cut off and taps are raised;

[0111] Zone 9: Reactive power exceeds the upper limit, capacitors are put into operation and taps are raised;

[0112] Zone 10: Reactive power exceeds the lower limit and voltage exceeds the lower limit, capacitors are cut off and taps are raised;

[0113] Zone 11: Reactive power approaches the lower limit and voltage exceeds the lower limit, increase the tap;

[0114] Zone 12: The voltage exceeds the lower limit, and the capacitor is put in and the tap is raised;

[0115] Zone 13: Reactive power exceeds the upper limit and voltage exceeds the lower limit, capacitors are added and taps are raised;

[0116] It should be noted that reactive power compensation is performed locally and on-site through reactive power compensation devices. Reactive power compensation locally refers to controlling the compensation devices of neighboring nodes to inject reactive power into the power grid and compensate for the reactive power demand of the current node based on the local balance characteristics of reactive power, so that reactive power flows in a smaller range and reduces the line loss in the substation area caused by reactive power.

[0117] By scanning the operating status data of each reactive compensation device, if it is found that the reactive power exceeds the limit in the same compensation combination, the host will issue a control instruction to the neighboring node of the exceeded node and make it enter the controlled state (no longer performing autonomous reactive power compensation) and perform nearby compensation for the exceeded node.

[0118] When at least one child node is communicating normally, the real-time status data of all nodes communicating normally are comprehensively considered, and a reactive power and voltage management strategy is adopted. First, the reactive power of the current head end is compensated to the maximum extent, and the control target is to minimize the reactive power of the head end and avoid over-compensation.

[0119] Secondly, for the regulation of the gear position of the on-load voltage regulation distribution transformer, the host will traverse all possible gear changes ΔL of the current transformer (assuming that the transformer has 9 gears and the current gear is 5, then ΔL can take any value in the interval [-4, 4]. When ΔL is positive, it represents an upshift operation, such as +2 represents an upshift of 2 gears. When ΔL is negative, it represents a downshift operation, such as -4 represents a downshift of 4 gears. When ΔL is 0, it means that the current gear remains unchanged.), and estimate the voltage value of each node after the gear adjustment, and then count the number of qualified nodes C among all nodes and cache them;

[0120] After the traversal is completed, the ΔL that makes C reach the maximum value is extracted as the adjustment target. Therefore, the basis for adjustment is the voltage data of all current nodes, and the control target is to maximize the number of qualified nodes.

[0121] According to the two situations, the power quality of the low-voltage distribution station area is regulated, the status of the head-end voltage and reactive power after regulation is collected, and the status of each node in the back-end area after regulation is collected to obtain the power risk information. The power risk information is represented by the head-end power safety concealment coefficient and the node impact risk assessment coefficient. The risk of power quality in the low-voltage distribution station area is quantified through a comprehensive analysis of the head-end power safety concealment coefficient and the node impact risk assessment coefficient.

[0122] The logic for obtaining the power safety concealment coefficient is: obtaining the performance of the head-end voltage and reactive power in the monitoring interval after regulation, collecting the head-end voltage in the monitoring interval, and marking the head-end voltage in the monitoring interval as: V i , where i = 1, 2, 3, ..., I, I is a positive integer, i is the number of each head-end power source collected during the monitoring period, the reactive power in the monitoring interval is collected, and the head-end reactive power in the monitoring interval is marked as: Q i ;

[0123] Set the operating range of the first-end voltage and mark the operating range of the first-end voltage as: V min ~V max, set the reactive power threshold at the first end, and mark the reactive power threshold at the first end as: Q YZ ;

[0124] It should be noted that the monitoring interval, the operating range of the head-end voltage and the head-end reactive power threshold are set by professional staff. The monitoring interval is a specific time period used to reflect the performance of the power quality in the background area after regulation. The operating range of the head-end voltage and the head-end reactive power threshold are usually determined according to the actual voltage and reactive power conditions in the area, which will not be elaborated here.

[0125] The collected head-end voltage within the monitoring interval is compared with the operating range of the head-end voltage to obtain the head-end power supply that is not within the operating range of the head-end voltage within the monitoring interval, and the head-end power supply that is not within the operating range of the head-end voltage is re-marked as: V k , where k=1, 2, 3, ..., K, K is a positive integer, and k is the number of the head-end power supply that is not within the operating range of the head-end voltage;

[0126] Calculate the voltage safety concealment coefficient, the calculation formula is: Among them, DY aq is the voltage safety concealment factor;

[0127] The collected head-end reactive power in the monitoring interval is compared with the head-end reactive power threshold, and the head-end reactive power greater than the head-end reactive power threshold in the monitoring interval is obtained, and the head-end reactive power greater than the head-end reactive power threshold is re-marked as: Q p , where p=1, 2, 3, ..., P, P is a positive integer, and p is the serial number of the head-end reactive power that is greater than the head-end reactive power threshold;

[0128] Calculate the reactive power safety concealment coefficient, the calculation formula is: Among them, GL aq is the reactive power safety concealment factor;

[0129] Calculate the power safety concealment coefficient, the calculation formula is: DN aq =(DY aq ×GL aq ) P+K ; Among them, the power safety concealment factor is DN aq .

[0130] It can be seen from the formula that the larger the power safety concealment coefficient is, the more it means that the head-end voltage and reactive power still change significantly after regulation, exceeding the normal power quality standards of the substation.

[0131] The logic for obtaining the node impact risk assessment coefficient is as follows: obtaining nodes of various types in the low-voltage distribution substation area, based on the current power quality data of nodes of various types in the low-voltage distribution substation area, combining the power quality problems and the impact of power quality that appear in the current power quality data of nodes of various types in the historical data, scoring nodes of different types by the expert equal weight principle, and determining the impact score values ​​of nodes of different types;

[0132] It should be noted that the division of node types is determined by constructing a topological structure diagram of the low-voltage distribution station area, clarifying the connection relationship between the trunk lines and branch nodes in the station area, and dividing the nodes based on the current node power quality data.

[0133] A regression model is constructed based on the proportion of each type of node in the low-voltage distribution substation area and the impact score of different types of nodes to obtain the node impact risk assessment coefficient. The expression of the node impact risk assessment coefficient is: Among them, JD yx is the node impact risk assessment coefficient, YX 1 , YX 2 , YX 3 ,……,YX j is the impact score of different types of nodes, SL 1 , SL 2 , SL 3 ,……,SL j is the proportion of the number of nodes of each type, j = 1, 2, 3, ..., J, J is a positive integer, and j is the number of nodes of each type in the current low-voltage distribution station area;

[0134] The logic for obtaining the proportion of each type of node is as follows: obtain the number of nodes in the current low-voltage distribution substation, obtain the node type in the current low-voltage distribution substation, and the calculation formula for the proportion of each type of node is as follows: Among them, LX j is the number of node types in the current low-voltage distribution station area, and e is a natural number.

[0135] It can be seen from the formula that the larger the node impact risk assessment coefficient is, the more different types of nodes there are in the current low-voltage distribution station area, and the possible risks may be higher.

[0136] The head-end power safety concealment coefficient and the node impact risk assessment coefficient are weighted and calculated to construct a control risk assessment model to generate a control risk assessment coefficient. The calculation formula of the control risk assessment coefficient is: Among them, PG tk is the control risk assessment coefficient, ε 1 , ε 2is the proportional coefficient of the head-end power safety concealment coefficient and the node impact risk assessment coefficient, ε 1 , ε 2 Both are greater than 0.

[0137] A control risk assessment coefficient threshold is set, and the control risk assessment coefficient is compared with the control risk assessment coefficient threshold. If the control risk assessment coefficient is greater than the control risk assessment coefficient threshold, a warning signal is generated to promptly notify professional staff to check the power quality problems in the substation. If the control risk assessment coefficient is less than the control risk assessment coefficient threshold, no warning signal is generated. By monitoring the moment when the three-phase load imbalance in the substation exceeds the limit, the above steps are repeated to achieve comprehensive voltage and reactive power control.

[0138] This embodiment provides two methods for comprehensive voltage and reactive power control in the substation when communication between substation nodes is abnormal, and quantifies the performance of the substation after being regulated by the voltage and reactive power comprehensive control method by monitoring the power quality data of the head end and other nodes in the substation. That is, when the power quality after regulation still does not meet the standard, the system will issue an early warning in time to remind the operation and maintenance personnel to take further measures to avoid power grid failure or equipment damage, which helps to maintain stable operation of the power grid.

[0139] Example 3

[0140] The device used to meet a grid-based regional collaborative comprehensive management method for power quality in a low-voltage distribution station area includes: a control host installed at the head end of the station area and an intelligent load dispatching circuit breaker deployed at each node in the station area, an integrated reactive power compensation device, and a wall-mounted single-phase voltage regulator;

[0141] The intelligent load dispatching circuit breaker is suitable for distribution networks with AC 50Hz, rated voltage 400V, and rated current below 250A. It integrates residual current protection circuit breaker, electronic molded case circuit breaker, and phase-changing switch, and is mainly used for distribution line protection and load dispatching.

[0142] The wall-mounted single-phase voltage regulator is a device that tracks the voltage changes of the terminal line and automatically controls the step-up and step-down units, so that the terminal voltage meets the national standards. The device is suitable for distribution lines with large user voltage fluctuations; the device is connected in series in a single-phase (three-phase) line and can automatically adjust the line voltage within a certain range to meet the national power supply voltage standard of +7% to -10%.

[0143] The integrated reactive power compensation device is a new generation reactive power compensation device, which is composed of a measurement and control unit, an instantaneous zero-crossing switching switch, a human-machine interaction unit, a protection unit, a self-healing low-voltage capacitor and a series reactor (or a low-voltage filter capacitor and a filter reactor);

[0144] The integrated reactive power compensation device and the wall-mounted single-phase voltage regulator have two operating states: autonomous regulation and controlled regulation. Autonomous regulation means that the integrated reactive power compensation device can autonomously collect and analyze the reactive power demand of the current node and automatically compensate. The wall-mounted single-phase voltage regulator can autonomously collect the voltage data of the current node and regulate the voltage of the current node according to its own preset adjustment logic, so that it can be kept within the preset qualified range as much as possible. The controlled regulation means that the integrated reactive power compensation device and the wall-mounted single-phase voltage regulator can receive the control instructions of the host through the lo ora module, and switch the state and implement the instructions according to the instructions. When entering the controlled regulation state, the two only receive the control instructions issued by the host and no longer perform autonomous regulation until the host actively switches its operating state back to the autonomous regulation state.

[0145] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0146] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented by software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website site, computer, server or data center to another website site, computer, server or data center by wired or wireless (e.g., infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that contains one or more available media sets. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state hard disk.

[0147] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0148] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example 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 performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0149] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0150] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0151] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage media include: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM), random access memories (RAM), magnetic disks or optical disks.

[0152] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for coordinated comprehensive management of power quality in a grid-based area in a low-voltage distribution station area, characterized in that: The following steps are involved: S1: The LoRa wireless module cyclically collects the power consumption status information of each node, and determines the power consumption status information of all nodes in the low-voltage distribution station area to implement a three-phase balance strategy; S2: Obtain the optimal dispatching instruction sequence through the differential evolution algorithm in the three-phase balancing strategy, perform phase switching operation on each node in the substation according to the optimal dispatching instruction sequence, and obtain the operation information and power quality information in the process of implementing the three-phase balancing strategy, wherein the differential deviation coefficient and the node balance abnormality coefficient are generated by analyzing the operation information and the power quality information. The logic for obtaining the differential deviation coefficient is: obtain the dispatching instruction of the final low-voltage distribution substation by using the differential evolution algorithm on the low-voltage distribution substation, determine the number of phase switchings and the final three-phase imbalance in the low-voltage distribution substation, and mark the number of phase switchings and the final three-phase imbalance in the low-voltage distribution substation as HX and PH respectively; Set the commutation number threshold and the three-phase imbalance threshold, take the ratio of the commutation number threshold to the commutation number in the low-voltage distribution station area as the commutation number deviation, and take the ratio of the three-phase imbalance threshold to the final three-phase imbalance in the low-voltage distribution station area as the three-phase imbalance deviation; Calculate the differential deviation coefficient using the formula: Among them, CF pc is the differential deviation coefficient, HX pc is the commutation frequency deviation, SX pc is the three-phase unbalance deviation; The logic for obtaining the node balance abnormality coefficient is: obtaining the three-phase imbalance of each node in the low-voltage distribution substation after the differential evolution algorithm is used, and marking the three-phase imbalance of each node in the low-voltage distribution substation after the differential evolution algorithm is used as: PH n , where n = 1, 2, 3, ..., N, N is a positive integer, and n is the number of each node in the low-voltage distribution station area; The average value and standard deviation of the three-phase imbalance of each node are obtained, and the average value and standard deviation of the three-phase imbalance of each node are marked as: PH avg and PH std ,in, Calculate the coefficient of variation of the three-phase unbalance degree of each node, and mark the coefficient of variation of the three-phase unbalance degree of each node as: Calculate the node balance abnormality coefficient, the calculation formula is: Among them, YC ph is the node balance abnormality coefficient; S3: Evaluate the performance of power quality in the substation after using the three-phase balance strategy. If the implementation of the optimal dispatch instruction sequence still cannot solve the three-phase imbalance problem, priority will be given to performing reactive power compensation or adjusting the voltage of each node, and generating an abnormal communication signal; S4: According to the time when the abnormal communication signal appears, the voltage and reactive power integrated control method is implemented, and the status of each node in the control background area is collected to obtain the power risk information; S5: Based on the power risk information, a control risk assessment model is constructed to generate a control risk assessment coefficient to quantify the performance of the background area after being controlled by the voltage and reactive power integrated control method.

2. According to claim 1, a method for coordinated comprehensive management of power quality in a grid-based low-voltage distribution station area is characterized in that: Implement a three-phase balancing strategy, including: According to the three-phase load data of the substation transformer collected at the current headend, the moment when the three-phase load imbalance exceeds the limit is determined, and a scheduling instruction sequence is generated through the differential evolution algorithm. It is then sent to each node through LoRa, and the node executes the load scheduling instruction. The scheduling instruction sequence includes the number of phase changes, the phase change load of the node, and the final three-phase imbalance of the substation.

3. A method for coordinated comprehensive management of power quality in a grid-based low-voltage distribution station area according to claim 2, characterized in that: Evaluate the performance of power quality in the substation after using the three-phase balancing strategy, including: The differential deviation coefficient and the node balance abnormality coefficient are comprehensively analyzed to establish a balance strategy evaluation model and generate a balance strategy evaluation coefficient. The expression of the balance strategy evaluation coefficient is: pg cl =β1CF pc +β2BY ph , where pg cl is the balance strategy evaluation coefficient, β1 and β2 are the proportional coefficients of the differential deviation coefficient and the node balance abnormality coefficient, respectively, and β1 and β2 are both greater than 0; Set a balance strategy evaluation coefficient threshold, and compare the balance strategy evaluation coefficient threshold with the balance strategy evaluation coefficient; If the balance strategy evaluation coefficient threshold is greater than the balance strategy evaluation coefficient, the three-phase balance strategy is executed according to the scheduling instruction sequence generated by the differential evolution algorithm; If the balancing strategy evaluation coefficient threshold is less than the balancing strategy evaluation coefficient, an abnormal communication signal is generated, and the three-phase balancing strategy cannot be executed according to the scheduling instruction sequence generated by the differential evolution algorithm. Priority is given to executing reactive power compensation or adjusting the voltage of each node.

4. A method for grid-based regional coordinated comprehensive management of power quality in low-voltage distribution station areas according to claim 3, characterized in that: According to the time when the abnormal communication signal appears, the voltage and reactive power comprehensive control method is implemented, including: When the communication with all other nodes is abnormal, the host will regulate the on-load voltage regulation and distribution transformer and reactive power compensation device at the head end in an orderly manner according to the head end voltage and reactive power status data collected by itself and the new nine-domain diagram, so as to realize the comprehensive control of voltage and reactive power based on the new nine-domain strategy. The abnormal state is communication timeout. When at least one child node is communicating normally, the real-time status data of all nodes communicating normally are comprehensively considered, and a reactive power and voltage management strategy is adopted. First, the reactive power of the current head end is compensated to the maximum extent, and the control target is to minimize the reactive power of the head end and avoid over-compensation. Secondly, for the regulation of the on-load voltage regulation and distribution transformer gear position, the host will traverse all possible gear position changes ΔL of the current transformer, and estimate the voltage value of each node after the gear adjustment, and then count the number of qualified nodes C among all nodes and cache them; After the traversal is completed, the ΔL that makes C reach the maximum value is extracted as the adjustment target. The basis for adjustment is the voltage data of all current nodes, and the control target is to maximize the number of qualified nodes.

5. A method for grid-based regional coordinated comprehensive management of power quality in low-voltage distribution station areas according to claim 4, characterized in that: The power quality of the low-voltage distribution station area is regulated, the status of the head-end voltage and reactive power after regulation is collected, and the status of each node in the back-end area after regulation is collected to obtain power risk information, which is represented by the head-end power safety concealment coefficient and the node impact risk assessment coefficient.

6. A method for grid-based regional coordinated comprehensive management of power quality in low-voltage distribution station areas according to claim 5, characterized in that: The logic for obtaining the electric energy safety concealment coefficient is: Obtain the performance of the head-end voltage and reactive power in the monitoring interval after regulation, collect the head-end voltage in the monitoring interval, and mark the head-end voltage in the monitoring interval as: V i , where i = 1, 2, 3, ..., I, I is a positive integer, i is the number of each head-end power source collected during the monitoring period, the reactive power in the monitoring interval is collected, and the head-end reactive power in the monitoring interval is marked as: Q i ; Set the operating range of the first-end voltage and mark the operating range of the first-end voltage as: V min ~V max , set the reactive power threshold at the first end, and mark the reactive power threshold at the first end as: Q YZ ; The collected head-end voltage within the monitoring interval is compared with the operating range of the head-end voltage to obtain the head-end power supply that is not within the operating range of the head-end voltage within the monitoring interval, and the head-end power supply that is not within the operating range of the head-end voltage is re-marked as: V k , where k=1, 2, 3, ..., K, K is a positive integer, and k is the number of the head-end power supply that is not within the operating range of the head-end voltage; Calculate the voltage safety concealment coefficient, the calculation formula is: Among them, DY aq is the voltage safety concealment factor; The collected head-end reactive power in the monitoring interval is compared with the head-end reactive power threshold, and the head-end reactive power greater than the head-end reactive power threshold in the monitoring interval is obtained, and the head-end reactive power greater than the head-end reactive power threshold is re-marked as: Q p , where p=1, 2, 3, ..., P, P is a positive integer, and p is the serial number of the head-end reactive power that is greater than the head-end reactive power threshold; Calculate the reactive power safety concealment coefficient, the calculation formula is: Among them, GL aq is the reactive power safety concealment factor; Calculate the power safety concealment coefficient, the calculation formula is: DN aq =(DY aq ×G Laq ) P+K ; Among them, the power safety concealment factor is DN aq .

7. A method for grid-based regional coordinated comprehensive management of power quality in low-voltage distribution station areas according to claim 6, characterized in that: The logic for obtaining the node impact risk assessment coefficient is: Obtain various types of nodes in the low-voltage distribution substation area, and based on the current power quality data of various types of nodes in the low-voltage distribution substation area, combine the power quality problems and the impact of power quality that appear in the current power quality data of various types of nodes in the historical data, score different types of nodes through the expert equal weight principle, and determine the impact score values ​​of different types of nodes; A regression model is constructed based on the proportion of each type of node in the low-voltage distribution substation area and the impact score of different types of nodes to obtain the node impact risk assessment coefficient. The expression of the node impact risk assessment coefficient is: Among them, JD yx is the node impact risk assessment coefficient, YX1, YX2, YX3, ..., YX j are the impact scores of different types of nodes, SL1, SL2, SL3, ..., SL j is the proportion of the number of nodes of each type, j = 1, 2, 3, ..., J, J is a positive integer, and j is the number of nodes of each type in the current low-voltage distribution station area; The logic for obtaining the proportion of each type of node is as follows: obtain the number of nodes in the current low-voltage distribution substation, obtain the node type in the current low-voltage distribution substation, and the calculation formula for the proportion of each type of node is as follows: Among them, LX j is the number of node types in the current low-voltage distribution station area, and e is a natural number.

8. A method for grid-based regional coordinated comprehensive management of power quality in low-voltage distribution station areas according to claim 7, characterized in that: The performance of the background area after quantitative control by voltage and reactive power comprehensive control method includes: The head-end power safety concealment coefficient and the node impact risk assessment coefficient are weighted and calculated to construct a control risk assessment model to generate a control risk assessment coefficient. The calculation formula of the control risk assessment coefficient is: Among them, PG tk To regulate the risk assessment coefficient, ε1 and ε2 are the proportional coefficients of the head-end power safety concealment coefficient and the node impact risk assessment coefficient, and ε1 and ε2 are both greater than 0; Set a control risk assessment coefficient threshold, and compare the control risk assessment coefficient with the control risk assessment coefficient threshold; If the control risk assessment coefficient is greater than the control risk assessment coefficient threshold, a warning signal is generated; If the control risk assessment coefficient is less than the control risk assessment coefficient threshold, no warning signal is generated. By monitoring the moment when the three-phase load imbalance in the substation exceeds the limit, steps S1 to S5 are repeated to achieve comprehensive voltage and reactive power control.

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