Power system safety control system and method based on main and distribution cooperation

Abstract

The invention discloses an electric power system safety control system and method based on main and distribution cooperation, particularly relates to the technical field of electric power control, and is used for solving the problem of poor electric power safety response. According to the method, power gathering is carried out on the boundary bus of the power distribution network through physical nodes and information nodes in the power distribution network, the minimum active power demand at the boundary bus of the power distribution network is solved according to the alternating current optimal power flow, the power controllable area of the power distribution network is determined, and therefore the controllable active power and reactive power range in the power distribution network is determined; performing electric power safety real-time monitoring on the power distribution network power controllable area, obtaining electric power configuration change information generated in the electric power safety real-time monitoring process of the power distribution network power controllable area, and determining the safe operation and control conditions of the power distribution network power controllable area; and corresponding electric power control measures are rapidly taken for maintenance according to different safety conditions, so that the accuracy of electric power safety analysis and the response timeliness of electric power control are improved.

Description

Technical Field

[0001] The present invention relates to the field of power control technology, and more specifically, to a power system safety control system and method based on main and distribution coordination. Background Art

[0002] The power system is one of the indispensable infrastructures in modern society. The power system supports various aspects such as industrial production, commercial activities, and social life. Any failure or accident in the power system may cause serious economic losses.

[0003] Deficiencies of existing technologies:

[0004] The power system consists of power plants, transmission networks, distribution systems, etc., involving a large number of equipment and complex control and regulation processes. With the growth of electricity demand and the addition of renewable energy, the operation of the power system has become more complex and changeable, and it faces a variety of safety hazards and challenges, such as overload, short circuit, frequency fluctuation, voltage instability, etc. These problems may be caused by various factors such as weather changes, equipment failures, and human operational errors, thus posing a threat to the safety and stability of the power system. The lack of overall consideration of the power system in terms of coordinated safety control of the main and distribution systems can easily lead to inaccurate power control processes, which in turn leads to greater power control risks. Summary of the invention

[0005] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a power system safety control system and method based on main-distribution coordination, which aggregates the power of the distribution network boundary bus through physical nodes and information nodes in the distribution network, and determines the power controllable area of ​​the distribution network according to the minimum active power demand at the distribution network boundary bus based on the AC optimal power flow, thereby determining the active power and reactive power range that can be controlled in the distribution network, and then, performs real-time power safety monitoring on the power controllable area of ​​the distribution network, obtains power configuration change information generated during the real-time power safety monitoring of the power controllable area of ​​the distribution network, determines the safe operation and control status of the power controllable area of ​​the distribution network, and quickly takes corresponding power control measures for maintenance according to different safety conditions, so as to solve the problems raised in the above-mentioned background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The power system safety control method based on main and distribution coordination includes the following steps:

[0008] Obtain the physical nodes and information nodes existing in the power system, and summarize the power of the distribution network boundary bus according to the physical nodes and information nodes in the distribution network;

[0009] The minimum active power demand at the boundary bus of the distribution network is solved by the AC optimal power flow to determine the controllable power area of ​​the distribution network, and the controllable active power and reactive power range in the distribution network is determined according to the controllable power area of ​​the distribution network;

[0010] Conduct real-time power safety monitoring of the power controllable area of ​​the distribution network, obtain information on power configuration changes generated during the real-time power safety monitoring of the power controllable area of ​​the distribution network, and determine the safe operation and control status of the power controllable area of ​​the distribution network;

[0011] If the safe operation and control status of the power controllable area of ​​the distribution network is normal, additional control measures will be taken. If the safe operation and control of the power controllable area of ​​the distribution network is abnormal, an unstable power transmission signal will be generated for early warning, and power control measures will be taken for maintenance.

[0012] In a preferred embodiment, the power controllable area of ​​the distribution network is determined by solving the minimum active power demand at the boundary bus of the distribution network through the AC optimal power flow. The specific process is as follows:

[0013] According to the topological structure and conductor parameters of the distribution network, the admittance matrix of the distribution network is established, the load model of the node is established according to the load characteristics of each node in the distribution network, and the power flow equation is established according to the admittance matrix and load model of the distribution network;

[0014] Determine the optimization target according to the power flow equation, and solve the optimal active demand variable based on the gradient method and interior point method;

[0015] The minimum active power demand value and the corresponding reactive power value at the boundary bus are determined according to the optimal active power demand variable, and are used to determine the boundary of the controllable area.

[0016] In a preferred embodiment, the power controllable area of ​​the distribution network is monitored for power safety in real time, and the power configuration change information generated during the power controllable area of ​​the distribution network is obtained. The specific process is as follows:

[0017] Power configuration change information includes fault impact risk information and regional node demand information;

[0018] The fault impact risk information includes the power loss load characterization index, and the regional node demand information includes the distribution node load drift index;

[0019] The power loss load characterization index and the distribution node load drift index are jointly calculated to obtain the safety control coefficient, and the generated safety control coefficient is compared with the safety control threshold to generate different signals.

[0020] In a preferred embodiment, the power loss load characterization index is obtained as follows:

[0021] Obtain the number of components n and the number of states s in the power controllable area of ​​the distribution network, obtain the probability of each component failing within a unit time t and use it as the failure rate, and establish the failure rate set SX i = {SX1,SX2,…,SX n}, calculate the controllable area failure rate, the calculation expression is: Calculate the load failure probability based on the controllable area failure rate: SF = 1-e -KQ*t , obtain the state z of the power controllable area of ​​the distribution network per unit time and the number of components m that have failed in the corresponding state, and calculate the failure rate and loss power G under state z z , the calculation expression is: Calculate the power loss load characterization index, the calculation expression is:

[0022] In a preferred embodiment, the load drift index of the distribution node is obtained as follows:

[0023] In the power controllable area of ​​the distribution network, obtain the number of power transmission lines NUM that can transmit power between nodes, as well as the power of distributed devices in the nodes, including active power P DG and reactive power Q DG , obtain the difference between the node voltage upper limit and the node lower limit ΔV, as well as the active power P of the node load FH and reactive power Q FH , obtain the conductance DG between the nodes of the power transmission line c Hediansu BG c And the voltage phase angle difference θ c , calculate the admittance value, the calculation expression is: DN xc =DG c *θ c *BG c *θ c , obtain the admittance value set of each node in the power controllable area of ​​the distribution network, and calculate the mean of the admittance value set to obtain the mean admittance value Calculate the load drift index of the distribution node, the calculation expression is:

[0024] In a preferred embodiment, if the safe operation and control status of the power controllable area of ​​the distribution network is normal, additional control measures are taken. If the safe operation and control of the power controllable area of ​​the distribution network are abnormal, a power transmission instability signal is generated for early warning, and power control measures are taken for maintenance. The specific process is as follows:

[0025] Compare the safety control factor with the safety control threshold;

[0026] If the safety control factor is greater than or equal to the safety control threshold, a power transmission stability signal is generated, indicating that the operation state of the distribution network is stable and no further control measures are required;

[0027] If the safety control coefficient is less than the safety control threshold, a power transmission risk fluctuation signal is generated, a power transmission status warning is issued, and corresponding power control measures are taken for maintenance.

[0028] The power system safety control system based on main power distribution coordination is used for the above-mentioned power system safety control method based on main power distribution coordination, including:

[0029] The power node information acquisition module obtains the physical nodes and information nodes in the power system, and summarizes the power of the distribution network boundary bus according to the physical nodes and information nodes in the distribution network;

[0030] The controllable area analysis module is used to determine the power controllable area of ​​the distribution network by solving the minimum active power demand at the boundary bus of the distribution network through the AC optimal power flow, and determine the controllable active power and reactive power range in the distribution network according to the power controllable area of ​​the distribution network;

[0031] The power safety confirmation module analyzes the power operation information obtained through monitoring, obtains the power configuration change information generated during the real-time power safety monitoring of the power controllable area of ​​the distribution network, and determines the safe operation and control status of the power controllable area of ​​the distribution network;

[0032] The control module takes additional control measures if the safe operation and control status of the power controllable area of ​​the distribution network is normal. If the safe operation and control of the power controllable area of ​​the distribution network is abnormal, an unstable power transmission signal is generated for early warning, and power control measures are taken for maintenance.

[0033] Technical effects and advantages of the present invention:

[0034] The present invention aggregates the power of the distribution network boundary bus through the physical nodes and information nodes in the distribution network, and determines the power controllable area of ​​the distribution network according to the minimum active power demand at the distribution network boundary bus according to the AC optimal power flow, thereby determining the active power and reactive power range that can be controlled in the distribution network, and then, performs real-time power safety monitoring on the power controllable area of ​​the distribution network, obtains the power configuration change information generated during the real-time power safety monitoring of the power controllable area of ​​the distribution network, determines the safe operation and control status of the power controllable area of ​​the distribution network, and quickly takes corresponding power control measures for maintenance according to different safety situations, thereby improving the accuracy of power safety analysis and the timeliness of power control response, and reducing the losses caused by power system failures. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1The present invention is a flow chart of a method for safe control of a power system based on coordination between the main power system and the distribution system.

[0036] Figure 2 It is a structural schematic diagram of the power system safety control system based on main and distribution coordination of the present invention. DETAILED DESCRIPTION

[0037] 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.

[0038] Example 1

[0039] like Figure 1 As shown, a power system safety control method based on main and distribution coordination includes:

[0040] Obtain the physical nodes and information nodes existing in the power system, and summarize the power of the distribution network boundary bus according to the physical nodes and information nodes in the distribution network;

[0041] The minimum active power demand at the boundary bus of the distribution network is solved by the AC optimal power flow to determine the controllable power area of ​​the distribution network, and the controllable active power and reactive power range in the distribution network is determined according to the controllable power area of ​​the distribution network;

[0042] Conduct real-time power safety monitoring of the power controllable area of ​​the distribution network, obtain information on power configuration changes generated during the real-time power safety monitoring of the power controllable area of ​​the distribution network, and determine the safe operation and control status of the power controllable area of ​​the distribution network;

[0043] If the safe operation and control status of the power controllable area of ​​the distribution network is normal, additional control measures will be taken. If the safe operation and control of the power controllable area of ​​the distribution network is abnormal, an unstable power transmission signal will be generated for early warning, and power control measures will be taken for maintenance.

[0044] The coordinated power system safety control is a method to ensure the stable operation of the power system by coordinating the main power control and the distribution network control. This method usually involves the following control processes:

[0045] Active power control: Active power control is usually implemented by the control center of the power plant or transmission system. It involves adjusting the power generation of the power plant, the transmission capacity of the transmission line, etc. to maintain the frequency and voltage stability of the power system. This control is usually adjusted based on the real-time status of the power system and load demand;

[0046] Distribution network control: Distribution network control involves monitoring and controlling each node in the distribution network to ensure that the power supply can be quickly switched when a fault or abnormal situation occurs in the system to reduce the impact on the system. This includes the control and adjustment of distribution switches, protection devices, etc.

[0047] Collaborative control: Collaboration is required between active power control and distribution network control to ensure that the system remains stable under various working conditions. This involves communication and coordination across different levels and regions to ensure that information can be transmitted and responded to in a timely manner.

[0048] The active power and reactive power of the transmission and distribution network interaction refer to the regulation capability of active power and reactive power involved in the energy exchange between the transmission network and the distribution network in the power system. This interaction generally occurs when the distribution network provides power to the transmission network, or when the transmission network provides power to the distribution network. Active power refers to the actual power transfer in the transmission of electric energy. Active power determines the load supply capacity in the power system. In the interaction of the transmission and distribution network, the regulation capability of active power means that the distribution network can provide or accept different amounts of active power to the transmission network as needed to meet different load requirements or system operating conditions. Reactive power is an important indicator for maintaining voltage stability in the power system. It is related to the capacitor and inductor components in the power system. The regulation capability of reactive power can be achieved by controlling capacitors, reactive compensation devices and other equipment to keep the voltage of the power system within a safe range. In the interaction of the transmission and distribution network, the distribution network can provide or absorb a certain amount of reactive power to help maintain the voltage stability of the entire system.

[0049] The distribution network to which distributed power sources are connected can provide reactive power reserves and improve the voltage of the transmission network by adjusting reactive power consumption. This method of adjusting reactive power consumption is usually achieved through distributed reactive power compensation devices. Distributed reactive power compensation devices can actively provide or absorb reactive power according to system needs to balance the reactive power demand in the power grid.

[0050] When there are a large number of distributed power sources in the distribution network, the distributed power sources can flexibly adjust their reactive power output to respond to the reactive power demand of the system. When voltage drops or voltage fluctuations occur in the distribution network, the distributed power sources can increase the voltage level of the power grid by providing additional reactive power. The injection of reactive power can increase the reactive reserve of the system and improve the stability and voltage quality of the power grid. When the voltage in the distribution network exceeds the rated level, the distributed power sources can adjust the voltage level of the power grid by absorbing excess reactive power. This absorption of reactive power can reduce the voltage of the power grid and prevent damage to system equipment caused by excessive voltage. At the same time, it helps balance the reactive power flow of the system. Through the flexible adjustment of reactive power consumption by distributed power sources, the distribution network can provide reactive reserves and improve the voltage level of the transmission network, thereby improving the stability and reliability of the entire power system.

[0051] There are multiple physical nodes and information nodes in the power system. Physical nodes refer to nodes or devices that actually exist in the power system, such as generators, substations, transmission lines, distribution lines, loads, etc. In the modeling and analysis of power systems, physical nodes are usually used to describe the topological structure, electrical parameters and actual operating status of the system. Physical nodes are interconnected through electrical connections to form the topological structure of the power system, which determines the path of energy transmission and system operation.

[0052] An information node refers to a node in a power system used for data collection, monitoring, control and communication, usually including sensors, measuring devices, communication equipment, etc. An information node monitors, regulates and manages the power system by transmitting real-time data, status information and control commands, and supports real-time monitoring, remote control, fault diagnosis, etc.

[0053] The physical nodes and information nodes of the distribution network are used together. The loads and distributed power sources in the distribution network can actively participate in the operation and management of the power grid by adjusting their active power and reactive power. The power of the boundary bus of the distribution network is aggregated. Assuming that the load of the i-th node is The power of distributed power generation is Where p represents active power, q represents reactive power, f represents load identifier, and d represents distributed power identifier;

[0054] The total net power demand in the distribution network can be expressed as the net power demand on the boundary bus, including the analysis of load, distributed generation power and loss related data. The expression of the net power demand value is: xq = ∑(p f +q f )+∑(p d +q d )+∑(p s +q s), where s is the loss identifier, including load, distributed generation power and loss related data.

[0055] Determine the controllable area of ​​the distribution network power and analyze the controllable area of ​​the distribution network power. The main and distribution coordinated control realizes the coordinated operation and optimized control of the power system by actively adjusting the operating parameters and control strategies of the main and distribution networks. The purpose of analyzing the controllable area of ​​the distribution network power is to determine the range of active power and reactive power that can be controlled in the distribution network. Analyzing the controllable area of ​​the distribution network power can provide basic data and constraints for the main and distribution coordinated control, help determine the power interaction range and control strategy between the main and distribution networks, and determine the power dispatch range and control strategy when distributed energy is connected, so as to cope with unforeseen situations such as sudden load changes and equipment failures, and improve the response capability of the power grid.

[0056] Solving the minimum active power demand at the boundary bus of the distribution network is the basis for solving the controllable area. It is solved through AC optimal power flow. The specific steps are as follows:

[0057] Establish an AC optimal power flow model, establish an AC optimal power flow model for the distribution network, including variables such as voltage, active power and reactive power of each node, and incorporate information such as the network topology, admittance matrix, and load model of the distribution network into the model;

[0058] Formulate an optimization problem, formalize the determined optimization objective function and constraints into an AC optimal power flow problem, usually a nonlinear programming (NLP) problem, in which the active power demand at the boundary bus is taken as an optimization variable and the reactive power is taken as a known quantity;

[0059] Specifically, the topological structure of the distribution network includes the connection relationship between each node, the conductor parameters of the branch, etc. The topological analysis is to determine the adjacent relationship of the nodes and establish the connection relationship matrix or connection relationship list between the nodes; according to the topological structure and conductor parameters of the distribution network, the admittance matrix of the distribution network is established. The admittance matrix describes the admittance relationship between each node in the distribution network and is the basis for power flow calculation; according to the load conditions of each node in the distribution network, including the size and nature of the load power (constant load, adjustable load, etc.), the load model of the node is established according to the load characteristics, including the model of active power and reactive power;

[0060] According to the admittance matrix and load model of the distribution network, the power flow equation is established. The power flow equation describes the relationship between the voltage, active power and reactive power of each node. The balance equation of the node voltage is: The branch flow equation is: Among them, V i represents the complex voltage at node i, P i and Q iRepresent the active power and reactive power of node i respectively, Y ij represents the admittance between node i and node j.

[0061] Determine the optimization goal of AC optimal power flow according to actual problems, such as minimizing total system loss, minimizing node voltage deviation, etc.; convert the objective function and constraints into mathematical expressions, and consider the safety constraints of the system, such as voltage limit, line capacity limit, etc.;

[0062] Use optimization algorithms, such as gradient-based methods and interior point methods, to solve for the optimal active power demand variable. In the solution process, consider the system's safety constraints, such as voltage limits and line capacity limits, to ensure that the solution meets system requirements.

[0063] According to the solution results, the minimum active power demand value at the boundary bus and the corresponding reactive power value are obtained. These results are used to determine the boundary of the controllable area and perform subsequent piecewise linearization processing.

[0064] The minimum active power demand is taken as the starting point of the controllable area, and an analysis is performed on the active power demand and reactive power plane to determine an acceptable active power demand range. Then, the corresponding reactive power range is determined according to the system's safety constraints and control strategies, and other constraints are determined, such as voltage limits, line capacity limits, etc., to ensure that the controllable area meets the safe operation requirements of the power grid.

[0065] For example, the minimum active power demand P at the boundary bus of the distribution network is obtained by solving the AC optimal power flow method: min , and the corresponding reactive power Q min ,Next, the range of the controllable area is determined according to the ,security constraints and control strategies of the system, and other ,constraints are determined to ensure that the controllable area meets the ,safe operation requirements of the power grid;

[0066] Set the acceptable active power range to [P min , P max ], i.e., the range from the minimum active power demand to the maximum active power demand, which is determined according to factors such as the load demand of electricity and the capacity of equipment;

[0067] According to the existing safety constraints and control strategies of the power system, the reactive power range corresponding to the active power range is determined. Generally, there is a certain relationship between reactive power and active power, and the range of reactive power can be determined by the power factor. For example, if the power factor of the system is required to be kept within a specific range, the range of reactive power can be determined based on the relationship between active power and power factor; for voltage restrictions, the minimum and maximum allowable voltage ranges can be determined to ensure the voltage stability of the system, and for line capacity restrictions, the maximum load capacity of each line can be determined to avoid equipment damage and grid failure caused by line overload. The above constraints are comprehensively considered to determine the specific range of the controllable area, that is, the active power range and the corresponding reactive power range, and the boundaries of the controllable area are drawn on the active power and reactive power planes for subsequent control and optimization.

[0068] The controllable region can also be subdivided into multiple sub-regions according to a specific piecewise linearization method. Each sub-region can have different linear characteristics and can be adjusted according to actual needs and control strategies;

[0069] Determine the boundary points of each sub-area. The boundary points are usually key nodes on the boundary of the controllable area, such as boundary bus, distributed power supply nodes, etc. Verify the controllable sub-area to determine whether it meets the safe operation and control requirements of the power system. When problems arise, timely adjust the control and redefine the controllable sub-area of ​​the distribution network power.

[0070] The determination of the power controllable area of ​​the distribution network can help achieve more effective coordinated control between the main grid and the distribution network and optimize the operating status of the power grid. The main grid and the distribution network can exchange and adjust power according to the range of the controllable area to maximize the energy utilization efficiency of the system, improve the adaptability and robustness of the power grid, and jointly formulate and implement control strategies to ensure that the operating status of each part of the system meets safety requirements and prevent instability or even accidents in the power grid.

[0071] Real-time verification of the power controllable area of ​​the distribution network is the key to ensuring the safe operation and control requirements of the power system. If it is found after verification that the power controllable area of ​​the distribution network does not meet the safe operation and control requirements of the power system, it is necessary to identify the problem and adjust the control strategy in a timely manner, and re-verify the safe operation of the power system under the new control strategy.

[0072] Conduct real-time power safety monitoring of the power controllable area of ​​the distribution network, analyze the power operation information obtained from the monitoring, and determine whether the power controllable area of ​​the distribution network meets the safe operation and control requirements of the power system. The specific steps are as follows:

[0073] Obtain the power configuration change information generated during the real-time power safety monitoring of the power controllable area of ​​the distribution network, and determine the safe operation and control status of the power controllable area of ​​the distribution network. The power configuration change information includes fault impact risk information and regional node demand information;

[0074] The fault impact risk information includes the power loss load characterization index and is calibrated as DLS, and the regional node demand information includes the distribution node load drift index and is calibrated as PDJ;

[0075] The power load loss characterization index in the fault impact risk information is used to indicate the risk level of the power system when the load cannot be met after a fault occurs. It is an indicator information determined based on the probability of the fault and the amount of load loss that may be caused after the fault. The power load loss characterization index is used to evaluate the impact of the power system on the load after the fault occurs, and to help power grid operators and decision makers better understand the reliability and stability of the system, so as to take corresponding measures to ensure the safe operation of the power system:

[0076] The power loss load characterization index provides key information for evaluating the impact of a power system failure on the load. By analyzing this index, the reliability and stability of the system can be evaluated, helping grid operators understand the operational safety of the system and take appropriate measures to ensure the safe operation of the power system. According to the evaluation results of the power loss load characterization index, corresponding emergency plans and response measures can be formulated. If the power loss load characterization index is high, it indicates that there is a risk that a large load in the system cannot be met, and emergency response and preventive measures need to be strengthened to ensure that a rapid response and handling can be made when a failure occurs.

[0077] According to the evaluation results of the power loss load characterization index, the equipment operation management in the system can be adjusted and optimized. By analyzing the amount of load loss that may be caused by system failure, the equipment operation strategy can be optimized, the system's emergency response capability can be improved, and the risk of load failure can be reduced.

[0078] The power loss load characterization index is obtained as follows:

[0079] Obtain the number of components n and the number of states s in the power controllable area of ​​the distribution network, obtain the probability of each component failing within a unit time t and use it as the failure rate, and establish the failure rate set SX i = {SX1,SX2,…,SX n}, calculate the controllable area failure rate, the calculation expression is: Calculate the load failure probability based on the controllable area failure rate: SF = 1-e -KQ*t, obtain the state z of the power controllable area of ​​the distribution network per unit time and the number of components m that have failed in the corresponding state, and calculate the failure rate and loss power G under state z z , the calculation expression is: Calculate the power loss load characterization index, the calculation expression is:

[0080] It should be noted that the power controllable area of ​​the distribution network includes multiple components, such as generators, transmission lines, transformers, etc. These components have a certain probability of failure; the number of operating states is the number of possible combinations under different operating states. In the distribution network, each component may be in different states, for example, a switch can be turned on or off, and a transformer can adjust different output voltages. Therefore, the number of operating states of the system is the number of possible combinations of all component states.

[0081] The larger the power loss load characterization index is, the higher the risk that the power controllable area of ​​the distribution network will not be able to meet the load demand after a fault occurs. The greater the risk to the power system as a whole, the larger the load loss characterization index is, the higher the probability that the power system will not be able to meet the load demand, and the corresponding decrease in power supply reliability, which is more likely to cause power outages or power quality problems for users, affecting the production and life of users. When the power system cannot meet the load demand, it may cause voltage fluctuations, frequency deviations and other problems, thus affecting the stable operation of the system. Especially in the case of large-scale load imbalance, it will cause the instability or even collapse of the power system.

[0082] The distribution node load drift index in the regional node demand information is used to evaluate the load stability of each node in the distribution network. The distribution node load drift index comprehensively considers the distributed equipment power, load power, voltage stability and electrical parameters between nodes at the node, aiming to evaluate the node's load supply capacity, voltage stability and power transmission between nodes, thereby revealing the importance of the node in the distribution network and the load stability;

[0083] The load drift index of the distribution node reflects the following aspects:

[0084] Load supply capacity: The active power and reactive power of the distributed equipment at the node, as well as the load power of the node, reflect the power supply capacity of the node in the distribution network;

[0085] Power transmission stability: The voltage of the node and the difference between the upper and lower limits of the voltage, the conductance, susceptance and voltage phase angle difference between the nodes describe the power transmission situation between the nodes and the electrical characteristics of the system, and reflect the stability and safety of the node voltage.

[0086] The load drift index of the distribution node is obtained as follows:

[0087] In the power controllable area of ​​the distribution network, obtain the number of power transmission lines NUM that can transmit power between nodes, as well as the power of distributed devices in the nodes, including active power P DG and reactive power Q DG , obtain the difference between the node voltage upper limit and the node lower limit ΔV, as well as the active power P of the node load FH and reactive power Q FH , obtain the conductance DG between the nodes of the power transmission line c Hediansu BG c And the voltage phase angle difference θ c , calculate the admittance value, the calculation expression is: DN xc =DG c *θ c *BG c *θ c , obtain the admittance value set of each node in the power controllable area of ​​the distribution network, and calculate the mean of the admittance value set to obtain the mean admittance value Calculate the load drift index of the distribution node, the calculation expression is:

[0088] It should be noted that the number of power transmission lines indicates the number of nodes that can transmit power to each other. For example, there are three nodes A, B, and C, and the power transmission direction is: A->B->C, then AB and BC are two power transmission lines, and AC cannot be used as a power transmission line; the power of distributed equipment can be obtained by monitoring or simulating the actual operating status of distributed equipment; the difference between the upper and lower limits of voltage indicates the stability of node voltage, which is calculated by the difference between the rated voltage and the actual measured value of the equipment at the node; in the power system, when the lines between different nodes in the power controllable area of ​​the same distribution network transmit power, parameters such as conductance, susceptance, and voltage phase angle difference are generated. For example, the conductance DG ij Hediansu BG ij It represents the admittance characteristics of the line between node i and node j, that is, the conductance and susceptance values ​​during power transmission. It is calculated through the physical parameters (such as resistance, inductance, capacitance) and length of the distribution network line, and is calculated through power system simulation software or an algorithm based on topology analysis. The voltage phase angle difference can be measured by a real-time monitoring system or calculated by simulation software.

[0089] The larger the load drift index of the distribution node, the greater the load fluctuation of the node, and the worse the load stability of the node, which may lead to problems such as voltage instability and line overload at the node, thus affecting the operation safety and stability of the entire distribution network. Therefore, the larger the load drift index of the distribution node, the worse it is, and corresponding measures need to be taken to improve the load stability of the node and ensure the normal operation of the distribution network.

[0090] The safety control coefficient is obtained by comprehensively calculating the power loss load characterization index and the distribution node load drift index. The expression is: In the formula, K x is the safety control coefficient, α and β are the preset proportional coefficients of the power loss load characterization index DLS and the distribution node load drift index PDJ, and α and β are both greater than 0.

[0091] It should be noted that the size of the preset proportional coefficient is to quantify each parameter to obtain a specific value. In order to facilitate subsequent comparison, the size of the coefficient depends on the amount of sample data and the preliminary setting of the corresponding preset proportional coefficient for each set of sample data by technical personnel in this field. It is not unique, as long as it does not affect the proportional relationship between the parameter and the quantized value, just like the inverse relationship between the load drift index of the distribution node and the safety control coefficient.

[0092] The smaller the power loss load characterization index and the smaller the distribution node load drift index, that is, the larger the performance value of the safety control coefficient, the more stable and safer the overall operation of the power controllable area of ​​the distribution network is. This means that the load of the power system in the power controllable area of ​​the distribution network can be met, and the load fluctuation of each node is small, which is conducive to ensuring the normal operation of the power grid, reducing the possibility of faults, and improving power supply reliability.

[0093] By comprehensively considering the power loss load characterization index and the distribution node load drift index, the safety control factor can more comprehensively evaluate the operating status of the distribution network. When the safety control factor is large, the operating risk of the system is relatively low, and operators can perform operation management with more confidence.

[0094] The larger the power loss load characterization index and the larger the load drift index of the distribution node, that is, the smaller the performance value of the safety control coefficient, the more unstable and unsafe the overall operation of the power controllable area of ​​the distribution network is. This means that when the distribution network faces a fault or load fluctuation, there is a risk that the load cannot be met. At the same time, the load fluctuation of the node is large, which may lead to unstable operation of the power grid, increase the possibility of faults, and reduce power supply reliability. Therefore, when the performance value of the safety control coefficient is small, corresponding measures need to be taken to improve the operating status of the distribution network, improve the power supply capacity and stability of the load, so as to ensure the normal operation and safety of the power grid.

[0095] Compare the generated safety control coefficient with the safety control threshold, generate different control signals, and adjust the corresponding control strategy according to the generated control signals;

[0096] After obtaining the safety control factor, compare the safety control factor with the safety control threshold;

[0097] If the safety control coefficient is greater than or equal to the safety control threshold, a power transmission stability signal is generated, indicating that the operation status of the distribution network is stable, all indicators are within the safety range, no further control measures are needed, the power system operates well, can meet the load demand, and ensure power supply reliability;

[0098] If the safety control coefficient is less than the safety control threshold, a power transmission risk fluctuation signal is generated, which means that there are unstable factors in the operation of the distribution network, and problems such as load imbalance, voltage instability, and power flow overload may occur. At this time, it is necessary to generate a power transmission instability signal and conduct a power transmission status warning to alert operation and maintenance personnel and decision makers of the abnormal operation of the distribution network. According to the generation of the power transmission instability signal, the operation and maintenance personnel can take corresponding power control measures in time, such as adjusting the generator output, adjusting the load distribution, switching the backup power supply, etc., to restore the stability of the distribution network and avoid further deterioration or failure of the system.

[0099] By comparing the safety control coefficient and the safety control threshold, the operating status of the distribution network can be monitored and evaluated in a timely manner, which helps to promptly identify potential problems and take effective measures to ensure the safe operation of the power system.

[0100] Upon receiving a power transmission risk fluctuation signal, appropriate measures should be taken in a timely manner to correct the abnormal situation;

[0101] For example, in a distribution network, the node load in a certain area suddenly fluctuates unstably, resulting in an increased risk of power transmission in that area. After receiving the risk fluctuation signal, the operation and maintenance personnel can take the following specific measures to restore the stability of the distribution network.

[0102] Increase the output power of some generators to compensate for unstable load fluctuations. For example, increase the output of adjustable generators to cope with sudden load increases;

[0103] Through the load dispatch system, part of the load is transferred from the affected area to other areas to balance the load distribution and reduce load fluctuations. For example, the operating time of some large industrial equipment is adjusted to smooth the load curve;

[0104] If there is a backup generator or battery system, it can be switched to the affected area to provide a stable backup power supply to cope with the fluctuation of the main power supply. For example, start the backup generator or use the battery system to stabilize the power supply, limit the power transmission amount to the affected area, and avoid overloading the power flow or line. For example, adjust the power supply range of the area and reduce the power transmission to other areas to reduce the line load;

[0105] Diagnose and handle possible faults that cause load fluctuations. For example, check the equipment and lines in the affected area, eliminate possible causes of the fault, and repair or replace the faulty equipment.

[0106] By taking the above measures in a timely manner, we can effectively respond to the problems exposed by the power transmission risk fluctuation signals, quickly restore the stability of the distribution network, reduce the impact of load fluctuations on the system, and ensure the normal operation of the power grid and power supply reliability.

[0107] It should be noted that the setting of security control thresholds can be determined according to specific scenarios and needs, and is usually adjusted and optimized based on historical data, performance indicators and other factors.

[0108] The present invention aggregates the power of the distribution network boundary bus through the physical nodes and information nodes in the distribution network, and determines the power controllable area of ​​the distribution network according to the minimum active power demand at the distribution network boundary bus according to the AC optimal power flow, thereby determining the active power and reactive power range that can be controlled in the distribution network, and then, performs real-time power safety monitoring on the power controllable area of ​​the distribution network, obtains the power configuration change information generated during the real-time power safety monitoring of the power controllable area of ​​the distribution network, determines the safe operation and control status of the power controllable area of ​​the distribution network, and quickly takes corresponding power control measures for maintenance according to different safety situations, thereby improving the accuracy of power safety analysis and the timeliness of power control response, and reducing the losses caused by power system failures.

[0109] Embodiment 2, this embodiment is a system embodiment of embodiment 1, which is used to implement the power system safety control method based on main and distribution coordination introduced in embodiment 1, such as Figure 2 As shown, specifically including:

[0110] The power node information acquisition module obtains the physical nodes and information nodes in the power system, and summarizes the power of the distribution network boundary bus according to the physical nodes and information nodes in the distribution network;

[0111] The controllable area analysis module is used to determine the power controllable area of ​​the distribution network by solving the minimum active power demand at the boundary bus of the distribution network through the AC optimal power flow, and determine the controllable active power and reactive power range in the distribution network according to the power controllable area of ​​the distribution network;

[0112] The power safety confirmation module analyzes the power operation information obtained through monitoring, obtains the power configuration change information generated during the real-time power safety monitoring of the power controllable area of ​​the distribution network, and determines the safe operation and control status of the power controllable area of ​​the distribution network;

[0113] The control module takes additional control measures if the safe operation and control status of the power controllable area of ​​the distribution network is normal. If the safe operation and control of the power controllable area of ​​the distribution network is abnormal, an unstable power transmission signal is generated for early warning, and power control measures are taken for maintenance.

[0114] The above formulas are all dimensionless and calculated numerically. Specific dimension removal can be achieved by various means such as standardization, which will not be elaborated here. 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.

[0115] The above embodiments can be implemented in whole or in part by software, hardware, firmware or any other combination. When implemented using 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, an ATA hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state ATA hard disk.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0120] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0121] 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 power system safety control method based on main and distribution coordination, characterized in that: The steps include: Obtain the physical nodes and information nodes existing in the power system, and summarize the power of the distribution network boundary bus according to the physical nodes and information nodes in the distribution network; The minimum active power demand at the boundary bus of the distribution network is solved by the AC optimal power flow to determine the controllable power area of ​​the distribution network, and the controllable active power and reactive power range in the distribution network is determined according to the controllable power area of ​​the distribution network; Conduct real-time power safety monitoring of the power controllable area of ​​the distribution network, obtain information on power configuration changes generated during the real-time power safety monitoring of the power controllable area of ​​the distribution network, and determine the safe operation and control status of the power controllable area of ​​the distribution network; If the safe operation and control status of the power controllable area of ​​the distribution network is normal, additional control measures will be taken. If the safe operation and control of the power controllable area of ​​the distribution network is abnormal, an unstable power transmission signal will be generated for early warning, and power control measures will be taken for maintenance.

2. The power system safety control method based on main and distribution coordination according to claim 1 is characterized in that: The power controllable area of ​​the distribution network is determined by solving the minimum active demand at the boundary bus of the distribution network through the AC optimal power flow. The specific process is as follows: According to the topological structure and conductor parameters of the distribution network, the admittance matrix of the distribution network is established, the load model of the node is established according to the load characteristics of each node in the distribution network, and the power flow equation is established according to the admittance matrix and load model of the distribution network; Determine the optimization target according to the power flow equation, and solve the optimal active demand variable based on the gradient method and interior point method; The minimum active power demand value and the corresponding reactive power value at the boundary bus are determined according to the optimal active power demand variable, and are used to determine the boundary of the controllable area.

3. The power system safety control method based on main and distribution coordination according to claim 2 is characterized in that: The power controllable area of ​​the distribution network is monitored in real time for power safety, and the power configuration change information generated during the real-time monitoring of power safety in the power controllable area of ​​the distribution network is obtained. The specific process is as follows: Power configuration change information includes fault impact risk information and regional node demand information; The fault impact risk information includes the power loss load characterization index, and the regional node demand information includes the distribution node load drift index; The power loss load characterization index and the distribution node load drift index are jointly calculated to obtain the safety control coefficient, and the generated safety control coefficient is compared with the safety control threshold to generate different signals.

4. The power system safety control method based on main and distribution coordination according to claim 3 is characterized in that: The power loss load characterization index is obtained as follows: Obtain the number of components n and the number of states s in the power controllable area of ​​the distribution network, obtain the probability of each component failing within a unit time t and use it as the failure rate, and establish the failure rate set SX i = {SX1,SX2,...,SX n }, calculate the controllable area failure rate, the calculation expression is: Calculate the load failure probability based on the controllable area failure rate: SF = 1-e -KQ*t , obtain the state z of the power controllable area of ​​the distribution network per unit time and the number of components m that have failed in the corresponding state, and calculate the failure rate and loss power G under state z z , the calculation expression is: Calculate the power loss load characterization index, the calculation expression is:

5. The power system safety control method based on main and distribution coordination according to claim 4 is characterized in that: The load drift index of the distribution node is obtained as follows: In the power controllable area of ​​the distribution network, obtain the number of power transmission lines NUM that can transmit power between nodes, as well as the power of distributed devices in the nodes, including active power P DG and reactive power Q DG , obtain the difference between the node voltage upper limit and the node lower limit ΔV, as well as the active power P of the node load FH and reactive power Q FH , obtain the conductance DG between the nodes of the power transmission line c Hediansu BG c And the voltage phase angle difference θ c , calculate the admittance value, the calculation expression is: DN xc =DG c *θ c *BG c *θ c , obtain the admittance value set of each node in the power controllable area of ​​the distribution network, and calculate the mean of the admittance value set to obtain the mean admittance value Calculate the load drift index of the distribution node, the calculation expression is:

6. The power system safety control method based on main and distribution coordination according to claim 5 is characterized in that: If the safe operation and control status of the power controllable area of ​​the distribution network is normal, additional control measures are taken. If the safe operation and control of the power controllable area of ​​the distribution network is abnormal, a power transmission instability signal is generated for early warning, and power control measures are taken for maintenance. The specific process is as follows: Compare the safety control factor with the safety control threshold; If the safety control factor is greater than or equal to the safety control threshold, a power transmission stability signal is generated, indicating that the operation state of the distribution network is stable and no further control measures are required; If the safety control coefficient is less than the safety control threshold, a power transmission risk fluctuation signal is generated, a power transmission status warning is issued, and corresponding power control measures are taken for maintenance.

7. A power system safety control system based on main and distribution coordination, used to implement a power system safety control method based on main and distribution coordination as claimed in any one of claims 1 to 6, characterized in that: include: The power node information acquisition module obtains the physical nodes and information nodes in the power system, and summarizes the power of the distribution network boundary bus according to the physical nodes and information nodes in the distribution network; The controllable area analysis module is used to determine the power controllable area of ​​the distribution network by solving the minimum active power demand at the boundary bus of the distribution network through the AC optimal power flow, and determine the controllable active power and reactive power range in the distribution network according to the power controllable area of ​​the distribution network; The power safety confirmation module analyzes the power operation information obtained through monitoring, obtains the power configuration change information generated during the real-time power safety monitoring of the power controllable area of ​​the distribution network, and determines the safe operation and control status of the power controllable area of ​​the distribution network; The control module takes additional control measures if the safe operation and control status of the power controllable area of ​​the distribution network is normal. If the safe operation and control of the power controllable area of ​​the distribution network is abnormal, an unstable power transmission signal is generated for early warning, and power control measures are taken for maintenance.

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