A method, system, device and medium for evaluating the transfer capability of a flexible ring closure device

Abstract

The present application belongs to the technical field of power systems, and particularly relates to a flexible loop closing device transfer capacity evaluation method, system, device and medium. First, a typical operation scenario set of a distribution network is formed, the distribution network operation scenario simulation and random fault simulation are performed, the number of times that each flexible loop closing device can complete loop closing operation and the number of times that the flexible loop closing device in the distribution network can complete loop closing operation are recorded, and the deviation of the transfer capacity of each flexible loop closing device and the transfer capacity of the flexible loop closing device in the distribution network is calculated, so as to evaluate the transfer capacity of each flexible loop closing device according to the deviation. The present application quantifies whether the flexible loop closing device can meet the demand of the distribution network by calculating the deviation of the transfer capacity of each flexible loop closing device and the transfer capacity of the flexible loop closing device in the distribution network, and reasonably and effectively judges the transfer capacity of the existing flexible loop closing device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power systems, and particularly relates to a flexible loop closing device transfer capacity evaluation method, system, device and medium. BACKGROUND

[0002] The flexible loop closing device is a key device for ensuring power transfer when the power grid fails, and is used to compensate for the voltage difference between two nodes of the power system to prevent excessive loop current caused by the voltage difference between the nodes during loop closing. The flexible loop closing device has become a key equipment in the distribution network. However, with the increase of distributed power sources, new energy systems and energy storage systems in the distribution network, the power supply diversity and uncertainty of the power grid have increased, and at the same time, with the increase of power load and demand changes, the power supply relationship of the distribution network changes from time to time. This means that when the power grid fails, the demand for voltage deviation between nodes solved by the flexible loop closing device will change, which deviates from the loop closing capacity planned in the early stage of the distribution network. Therefore, it is necessary to analyze the voltage compensation capacity or transfer level of the flexible loop closing device in the distribution network, evaluate whether it can meet the current development status of high proportion of new energy, distributed voltage and energy storage system, and estimate the probability that it can meet the current power transfer of the distribution network.

[0003] At present, the research on the flexible loop closing device is mostly limited to the structure design of the flexible loop closing device itself, the operation control strategy research of the loop closing, and the optimization analysis of the capacity and access position of the flexible loop closing device. There is insufficient research on whether the transfer capacity of the existing flexible loop closing device of the current distribution network can meet the demand of the distribution network. SUMMARY

[0004] The purpose of the present application is to provide a flexible loop closing device transfer capacity evaluation method, system, device and medium to solve the technical problem that the existing technology cannot evaluate whether the transfer capacity of the existing flexible loop closing device of the current distribution network can meet the demand of the distribution network.

[0005] In order to solve the above technical problems, the present application adopts the following technical solutions:

[0006] In a first aspect, the present application provides a flexible loop closing device transfer capacity evaluation method, comprising the following steps:

[0007] S1. Obtain a set of typical operation scenarios of the distribution network;

[0008] S2. Simulate the operation scenarios of the distribution network according to the set of typical operation scenarios of the distribution network, and obtain the output power of the distributed power source, new energy power station and energy storage system on each power grid node of the distribution network within a typical day;

[0009] S3. Perform power distribution network fault simulation, and obtain the voltage vector of each power grid node in the power distribution network according to the output power of the distributed power supply, new energy power station and energy storage system at each power grid node in the power distribution network within a typical day;

[0010] S4. Obtain the voltage vector of the two power grid nodes connected by the flexible loop closing device, determine whether the flexible loop closing device can complete the loop closing operation, and record the number of times that each flexible loop closing device can complete the loop closing operation and the number of times that the flexible loop closing device in the power distribution network can complete the loop closing operation;

[0011] S5. Calculate the total number of power distribution network operation simulation analysis, and calculate the transfer capacity of each flexible loop closing device and the deviation of the transfer capacity of the flexible loop closing device in the power distribution network according to the number of times that each flexible loop closing device can complete the loop closing operation and the number of times that the flexible loop closing device in the power distribution network can complete the loop closing operation;

[0012] S6. According to the deviation of the transfer capacity of each flexible loop closing device and the transfer capacity of the flexible loop closing device in the power distribution network, the transfer capacity of each flexible loop closing device is evaluated.

[0013] Further, the step of obtaining the typical operation scenario set of the power distribution network specifically comprises:

[0014] Obtain the historical operation data of the new energy power station and the user load at each power grid node of the power distribution network;

[0015] According to the historical operation data of the new energy power station and the user load at each power grid node of the power distribution network, a typical daily operation scenario of the new energy power station and the user load is established by using a scene generation and reduction method, and a typical operation scenario set of the power distribution network is formed

[0016]

[0017] Wherein: is a typical daily operation scenario, m is the serial number of the typical daily operation scenario, the initial value of m is 1, and M represents the maximum simulation number of the operation scenario of the power distribution network.

[0018] Further, the step of simulating the operation scenario of the power distribution network according to the typical operation scenario set of the power distribution network and obtaining the output power of the distributed power supply, new energy power station and energy storage system at each power grid node of the power distribution network within a typical day specifically comprises:

[0019] Obtain the number of power grid nodes, the output active power, the output reactive power, the output current, the resistance, the reactance between the power grid nodes, the daily forecast output active power of the new energy power station, the installed capacity of the new energy power station, the capacity state of the energy storage system, the charging efficiency of the energy storage system, and the discharging efficiency of the energy storage system;

[0020] The optimization variables of the optimal power flow calculation method of the power distribution network are selected, including: actual active power and reactive power variables of a new energy power station, actual active power and reactive power variables of a storage system, voltages of each power network node on the power network, currents on each power network branch, and actual active power and reactive power variables obtained by a power load;

[0021] An optimization objective function for guaranteeing power supply for loads to the maximum extent is defined, and the formula is as follows:

[0022]

[0023] Wherein, J is the objective function; Node represents the number of power network nodes; X load,i (t) represents actual active power obtained by a power load on the i th power network node at t moment; P load,i (t) represents active power of the load on the i th power network node at t moment; Y load,i (t) represents actual reactive power obtained by a power load on the i th power network node at t moment; Q load,i (t) represents reactive power of the load on the i th power network node at t moment;

[0024] The operation constraints of the regional power distribution network are set;

[0025] According to each typical daily operation scenario in the typical operation scenario set of the power distribution network, the active power, the reactive power output of the distributed power source, the new energy power station and the storage system, and the voltage and branch current information of each power network node in the power distribution network are calculated by using the optimal power flow calculation method when all the flexible loop devices and tie switches in the power distribution network are disconnected, so as to obtain the output power of the distributed power source, the new energy power station and the storage system on each power network node in the power distribution network in a typical day;

[0026] The operation constraints of the regional power distribution network include:

[0027] The active power and reactive power balance constraints of the power system are as follows:

[0028]

[0029] Wherein, X E,i (t) represents actual output active power of the storage system of the i th power network node at t moment; X new,i (t) represents actual output active power of the new energy power station of the i th power network node at t moment; P i,j (t) represents active power output from the i th power network node to the j th power network node; I i,j (t) represents current square output from the i th power network node to the j th power network node; R i,jrepresents the resistance between the power grid node j and the power grid node i; Y E,i (t) represents the actual output reactive power of the energy storage system of the i-th power grid node at time t; Y new,i (t) represents the actual output reactive power of the new energy power plant of the i-th power grid node at time t; Q i,j (t) represents the reactive power output from the i-th power grid node to the j-th power grid node; X i,j represents the reactance between the power grid node j and the power grid node i;

[0030] Node voltage and line current constraints, the formula is as follows:

[0031]

[0032] wherein: U i (t) represents the square of the voltage of the i-th power grid node at time t; U j (t) represents the square of the voltage of the j-th power grid node at time t; represents the square of the lower limit value of the voltage of the power grid node; represents the square of the upper limit value of the voltage of the power grid node; I max represents the maximum passing current of the branch;

[0033] New energy power output constraints, the formula is as follows:

[0034]

[0035] wherein: P new,i (t) represents the maximum output active power of the new energy power plant of the i-th power grid node at time t; S new,i represents the installed capacity of the new energy power plant of the i-th power grid node;

[0036] Energy storage system energy balance constraints, the formula is as follows:

[0037]

[0038] wherein: C E,i (t+Δt) represents the capacity state of the energy storage system at time t+Δt on the i-th power grid node; Δt represents the time interval; C E,i (t) represents the capacity state of the energy storage system at time t on the i-th power grid node; represents the charging efficiency of the energy storage system on the i-th power grid node; represents the discharging efficiency of the energy storage system on the i-th power grid node; represents the lower limit value of the capacity state of the energy storage system on the i-th power grid node; represents the upper limit value of the capacity state of the energy storage system on the i th power grid framework node; C E,i (1) represents the initial capacity of the energy storage system on the i th power grid framework node in a typical day; C E,i t ) represents the final capacity of the energy storage system on the i th power grid framework node in a typical day; N t represents the total number of time points N t in a typical day.

[0039] Further, the step of performing power distribution network fault simulation and obtaining the voltage vector of each power grid framework node in the power distribution network according to the output power of the distributed power supply, new energy power station and energy storage system on each power grid framework node in the power distribution network in a typical day, specifically comprises:

[0040] Randomly simulate the fault conditions of the power distribution network at different times and different locations, and obtain the structure parameters of the power distribution network after the fault occurs;

[0041] According to the structure parameters of the power distribution network after the fault occurs, and the output power of the distributed power supply, new energy power station and energy storage system on each power grid framework node in the power distribution network in a typical day, calculate the power flow of the power distribution network after the fault occurs, and obtain the voltage amplitude and phase of each power grid framework node in the power distribution network;

[0042] According to the voltage amplitude and phase of each power grid framework node in the power distribution network, form the voltage vector of each power grid framework node in the power distribution network.

[0043] Further, the step of obtaining the voltage vector of the two power grid framework nodes connected by the flexible loop device, judging whether the flexible loop device can complete the loop operation, and recording the number of times that each flexible loop device can complete the loop operation and the number of times that the flexible loop device in the power distribution network can complete the loop operation, specifically comprises:

[0044] Obtain the transfer capacity, resistance, reactance of the flexible loop device and the voltage vector of the two power grid framework nodes connected by the flexible loop device;

[0045] S4.1. Let the flexible loop device sequence number r=1, and define the loop success flag Flag=1;

[0046] S4.2. Calculate the maximum transfer current of the r th flexible loop device The formula is as follows:

[0047]

[0048] Wherein: is the conjugate vector of , R H (r) is the resistance of the flexible loop device, and j is the imaginary unit.​H (r) is the transfer capacity of the flexible loop device, r e 1, 2,..., R, R is the number of flexible loop devices in the distribution network; H (r) is the transfer capacity of the flexible loop device, r e 1, 2,..., R, R is the number of flexible loop devices in the distribution network;

[0049] Calculate the required transfer current of the rth flexible loop device The formula is as follows:

[0050]

[0051] Wherein: And are the voltage vectors of the two power grid frame nodes connected by the rth flexible loop device;

[0052] Determine the maximum transfer current of the rth flexible loop device Whether the required transfer current of the rth flexible loop device Satisfies the following inequality:

[0053]

[0054] If yes, the number of times N that the rth flexible loop device can complete loop operation when the distribution network fails s (r) is added by 1, and the loop success flag Flag is set to 0; if no, go to step S4.3;

[0055] Wherein, N s (r) is initially 0;

[0056] S4.3. Determine whether the loop success flag Flag is equal to 1;

[0057] If yes, the number of times N that the flexible loop device in the distribution network can complete loop operation when the distribution network fails s Is added by 1; if no, go to step S4.4;

[0058] Wherein, N s Is initially 0;

[0059] S4.4. Determine whether the flexible loop device serial number r is less than the number R of flexible loop devices in the distribution network;

[0060] If yes, the flexible loop device serial number r is added by 1 and returns to step S4.2; if no, go to step S4.5;

[0061] S4.5. Determine whether the distribution network failure simulation number n is less than the preset maximum number N of distribution network failure simulations;

[0062] If yes, the distribution network failure simulation number n is added by 1 and returns to step S3; if no, go to step S4.6;

[0063] S4.6. Determine whether the typical day operation scenario sequence number m is less than the maximum simulation number M of the distribution network operation scenario;

[0064] If yes, the typical day operation scenario sequence number m is increased by 1, the distribution network fault simulation number n is set to 1, and the process returns to step S2; if no, the N s (r) at this time is recorded, and the process proceeds to step S5. s

[0065] Further, the step of calculating the total number of distribution network operation simulation analysis and calculating the deviation of the transfer capacity of each flexible loop device from the transfer capacity of the flexible loop devices in the distribution network based on the number of times each flexible loop device can complete loop operation and the number of times the flexible loop devices in the distribution network can complete loop operation, specifically includes:

[0066] The total number of distribution network operation simulation analysis S is calculated, and the formula is as follows:

[0067] S = M x N

[0068] The transfer capacity C s of the flexible loop devices in the distribution network is calculated, and the formula is as follows:

[0069] C s = N s / S

[0070] The transfer capacity C s (r) of the rth flexible loop device is calculated, and the formula is as follows:

[0071] C s (r) = N s (r) / S

[0072] The deviation of the transfer capacity of the rth flexible loop device from the transfer capacity of the flexible loop devices in the distribution network is C s (r) - C s |.

[0073] Further, the step of evaluating the transfer capacity of each flexible loop device based on the deviation of the transfer capacity of each flexible loop device from the transfer capacity of the flexible loop devices in the distribution network, specifically includes:

[0074] The deviation C s (r) - C s | of the transfer capacity of the rth flexible loop device from the transfer capacity of the flexible loop devices in the distribution network is compared with a set threshold value;

[0075] C s (r) - C s ​| Greater than the set threshold, the transfer capacity evaluation result of the rth flexible loop device is: insufficient capacity, and the rth flexible loop device needs to be capacity expanded and reconstructed;

[0076] |C s (r)-C s | Less than or equal to the set threshold, the transfer capacity evaluation result of the rth flexible loop device is: sufficient capacity, and the rth flexible loop device does not need to be capacity expanded and reconstructed.

[0077] In a second aspect, the present application provides a flexible loop device transfer capacity evaluation system, comprising:

[0078] A typical operation scenario acquisition module is configured to acquire a set of typical operation scenarios of a power distribution network;

[0079] An operation scenario simulation module is configured to simulate operation scenarios of the power distribution network according to the set of typical operation scenarios of the power distribution network, and acquire output powers of distributed power sources, new energy power stations and energy storage systems at each power grid node of the power distribution network within a typical day;

[0080] A fault simulation module is configured to simulate faults of the power distribution network, and acquire voltage vectors of each power grid node in the power distribution network according to the output powers of the distributed power sources, the new energy power stations and the energy storage systems at each power grid node of the power distribution network within the typical day;

[0081] A loop operation record module is configured to acquire voltage vectors of two power grid nodes connected by a flexible loop device, determine whether the flexible loop device can complete loop operation, and record the number of times that each flexible loop device can complete loop operation and the number of times that the flexible loop devices in the power distribution network can complete loop operation;

[0082] A deviation calculation module is configured to calculate the total number of times of operation simulation analysis of the power distribution network, and calculate the deviation of the transfer capacity of each flexible loop device from the transfer capacity of the flexible loop devices in the power distribution network according to the number of times that each flexible loop device can complete loop operation and the number of times that the flexible loop devices in the power distribution network can complete loop operation;

[0083] An evaluation module is configured to evaluate the transfer capacity of each flexible loop device according to the deviation of the transfer capacity of each flexible loop device from the transfer capacity of the flexible loop devices in the power distribution network.

[0084] In a third aspect, the present application provides an electronic device comprising a processor and a memory, wherein the processor is configured to execute a computer program stored in the memory to implement the flexible loop device transfer capacity evaluation method.

[0085] In a fourth aspect, the present application provides a computer readable storage medium storing at least one instruction, which, when executed by a processor, implements the flexible looped-in device transfer capacity evaluation method.

[0086] Compared with the prior art, the present application has the following beneficial effects:

[0087] The present application provides a flexible looped-in device transfer capacity evaluation method, system, device and medium, the method comprising:

[0088] S1. Obtain a set of typical operation scenarios of the power distribution network;

[0089] S2. Simulate the operation scenarios of the power distribution network according to the set of typical operation scenarios of the power distribution network, and obtain the output power of the distributed power supply, new energy power station and energy storage system on each power grid node of the power distribution network within a typical day;

[0090] S3. Perform fault simulation of the power distribution network, and obtain the voltage vector of each power grid node in the power distribution network according to the output power of the distributed power supply, new energy power station and energy storage system on each power grid node of the power distribution network within a typical day;

[0091] S4. Obtain the voltage vectors of the two power grid nodes connected by the flexible looped-in device, determine whether the flexible looped-in device can complete the looped-in operation, and record the number of times each flexible looped-in device can complete the looped-in operation and the number of times the flexible looped-in device in the power distribution network can complete the looped-in operation;

[0092] S5. Calculate the total number of times of operation simulation analysis of the power distribution network, and calculate the deviation of the transfer capacity of each flexible looped-in device and the transfer capacity of the flexible looped-in device in the power distribution network according to the number of times each flexible looped-in device can complete the looped-in operation and the number of times the flexible looped-in device in the power distribution network can complete the looped-in operation;

[0093] S6. Evaluate the transfer capacity of each flexible looped-in device according to the deviation of the transfer capacity of each flexible looped-in device and the transfer capacity of the flexible looped-in device in the power distribution network.

[0094] The present application quantifies whether the flexible looped-in device can meet the demand of the power distribution network by calculating the deviation of the transfer capacity of each flexible looped-in device and the transfer capacity of the flexible looped-in device in the power distribution network, thereby providing a basis for evaluating the transfer capacity of the flexible looped-in device. The transfer capacity of the existing flexible looped-in device is reasonably and effectively judged by simulating a large number of and comprehensive operation scenarios and fault conditions of the power distribution network. BRIEF DESCRIPTION OF DRAWINGS

[0095] The drawings constituting a part of this disclosure are used to provide further understanding of the present disclosure, and the illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure, and do not constitute improper limitations on the present disclosure. In the drawings:

[0096] Figure 1 A flow chart of a flexible loop device transfer capacity evaluation method of the present application;

[0097] Figure 2 A structural diagram of a flexible loop device transfer capacity evaluation system of the present application;

[0098] Figure 3 A structural block diagram of an electronic device of the present application;

[0099] Figure 4 A power network structural diagram in an embodiment of the present application. DETAILED DESCRIPTION

[0100] The present application will be described in detail below with reference to the drawings and in conjunction with embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0101] The following detailed description is exemplary description, which is intended to provide further detailed description of the present application. Unless otherwise specified, all technical terms used in the present application have the same meaning as generally understood by those skilled in the art to which the present application belongs. The terms used in the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the exemplary embodiments according to the present application.

[0102] Embodiment 1

[0103] For example, as shown in the power network structure, Figure 4 As shown in the power network structure, Figure 4 The two distributed power sources, new energy power stations including two photovoltaic power stations, two energy storage systems and load user access position conditions have been marked in the figure. The new energy power station can perform output active and reactive power regulation. The flexible loop device has a total of five, which are connected between node 8 and node 21, node 12 and node 22, node 9 and node 15, node 25 and node 29, and node 18 and node 33. The application of the flexible loop device can compensate for the voltage difference between the two power network nodes when the fault occurs. When the voltage difference between the two nodes is zero, the tie switch is connected again. When the fault is restored, the tie switch is disconnected, and the two power network nodes are not connected.

[0104] As shown in the power network structure, Figure 1 The present application provides a flexible loop device transfer capacity evaluation method, which specifically comprises the following steps:

[0105] S1. Obtain a set of typical operation scenarios of the distribution network;

[0106] Obtain the historical operation data of new energy power plants and user loads on each power grid node of the power distribution network, and use a scenario generation and reduction method to establish typical daily operation scenarios of new energy power plants and user loads, thereby forming a typical operation scenario set of the power distribution network

[0107]

[0108] wherein: is a typical daily operation scenario, m is the serial number of the typical daily operation scenario, the initial value of m is 1, and M represents the maximum simulation number of the operation scenarios of the power distribution network.

[0109] S2. Simulate the operation scenarios of the power distribution network according to the typical operation scenario set of the power distribution network, and obtain the output power of distributed power sources, new energy power plants and energy storage systems on each power grid node of the power distribution network within a typical day, which specifically includes the following steps:

[0110] Obtain the number of power grid nodes, the output active power, the output reactive power, the output current, the resistance and the reactance between the power grid nodes, the day-ahead predicted output active power of the new energy power plant, the installed capacity of the new energy power plant, the capacity state of the energy storage system, the charging efficiency of the energy storage system and the discharging efficiency of the energy storage system.

[0111] Select the optimization variables of the optimal power flow calculation method of the power distribution network, including: the actual output active power and reactive power variables of the new energy power plant, the output active power and reactive power variables of the energy storage system, the voltage of each power grid node on the power network and the current on each power network branch, and the actual obtained active power and reactive power variables of the power load;

[0112] Define an optimization objective function for guaranteeing power supply to the load to the greatest extent, and the formula is as follows:

[0113]

[0114] wherein: J is the objective function; Node represents the number of power grid nodes; X load,i (t) represents the actual obtained active power of the power load on the i-th power grid node at t time; P load,i (t) represents the active power of the load on the i-th power grid node at t time; Y load,i (t) represents the actual obtained reactive power of the power load on the i-th power grid node at t time; Q load,i (t) represents the reactive power of the load on the i-th power grid node at t time.

[0115] Set the operation constraints of the regional power distribution network, including:

[0116] The active power and reactive power balance constraints of the power system, and the formula is as follows:

[0117]

[0118] wherein: X E,i (t) represents the actual output active power of the energy storage system of the i-th power grid framework node at time t; X new,i (t) represents the actual output active power of the new energy power station of the i-th power grid framework node at time t; P i,j (t) represents the active power output from the i-th power grid framework node to the j-th power grid framework node; I i,j (t) represents the current square output from the i-th power grid framework node to the j-th power grid framework node; R i,j represents the resistance between the power grid framework node j and the power grid framework node i; Y E,i (t) represents the actual output reactive power of the energy storage system of the i-th power grid framework node at time t; Y new,i (t) represents the actual output reactive power of the new energy power station of the i-th power grid framework node at time t; Q i,j (t) represents the reactive power output from the i-th power grid framework node to the j-th power grid framework node; X i,j represents the reactance between the power grid framework node j and the power grid framework node i;

[0119] Node voltage and line current constraints, the formula is as follows:

[0120]

[0121] wherein: U i (t) represents the square of the voltage of the i-th power grid framework node at time t; U j (t) represents the square of the voltage of the j-th power grid framework node at time t; represents the square of the lower limit value of the power grid framework node voltage; represents the square of the upper limit value of the power grid framework node voltage; I max represents the maximum passing current of the branch;

[0122] New energy power output constraints, the formula is as follows:

[0123]

[0124] wherein: P new,i (t) represents the maximum output active power of the new energy power station of the i-th power grid framework node at time t; S new,i represents the installed capacity of the new energy power station of the i-th power grid framework node;

[0125] Energy storage system energy balance constraints, the formula is as follows:

[0126]

[0127] wherein: C E,i (t+Δt) represents the capacity state of the energy storage system at the i-th power grid framework node at time t+Δt; Δt represents a time interval; C E,i (t) represents the capacity state of the energy storage system at the i-th power grid framework node at time t; represents the charging efficiency of the energy storage system at the i-th power grid framework node; represents the discharging efficiency of the energy storage system at the i-th power grid framework node; represents the lower limit value of the capacity state of the energy storage system at the i-th power grid framework node; represents the upper limit value of the capacity state of the energy storage system at the i-th power grid framework node;C E,i (1) represents the initial capacity of the energy storage system at the i-th power grid framework node in a typical day;C E,i (N t ) represents the final capacity of the energy storage system at the i-th power grid framework node in a typical day;N t represents the total number of time points N t in a typical day;

[0128] According to each typical daily operation scenario in the typical operation scenario set of the distribution network, the optimal power flow calculation method is used to calculate the active power, reactive power output of the distributed power supply, new energy power station and energy storage system, and the voltage and branch current information of each power grid framework node in the distribution network when all the flexible loop devices and tie switches are disconnected, so as to obtain the output power of the distributed power supply, new energy power station and energy storage system at each power grid framework node in the distribution network in a typical day.

[0129] S3. Fault simulation of the distribution network is performed, and the voltage vector of each power grid framework node in the distribution network is obtained according to the output power of the distributed power supply, new energy power station and energy storage system at each power grid framework node in the distribution network in a typical day, specifically including the following steps:

[0130] Randomly simulate the fault occurring at different times and different positions in the distribution network, at this time the flexible loop device does not work, and the tie switch of the distribution network is not closed; therefore, the radial distribution network will become two independent power grids, and the ring distribution network will become a radial distribution network; according to the structure of the distribution network after the fault, define the balance, PQ, PV and other node types, and the basic elements for solving power flow such as power grid connection matrix and admittance matrix, so as to obtain the structure parameters of the distribution network after the fault;

[0131] According to the distribution network structure parameters after the fault occurs, and the output power of the distributed power, new energy power station and energy storage system on each power grid node in the distribution network within a typical day, the Newton-Raphson method is used to calculate the power flow of the distribution network after the fault occurs, to obtain the voltage amplitude and phase of each power grid node in the distribution network, and form the voltage vector of each power grid node in the distribution network.

[0132] S4. Obtain the voltage vector of the two power grid nodes connected by the flexible loop device, judge whether the flexible loop device can complete the loop operation, and record the number of times that each flexible loop device can complete the loop operation and the number of times that the flexible loop device in the distribution network can complete the loop operation, which specifically includes the following steps:

[0133] Obtain the transfer capacity, resistance, reactance of the flexible loop device and the voltage vector of the two power grid nodes connected by the flexible loop device;

[0134] S4.1. Let the flexible loop device sequence number r=1, and define the loop success flag Flag=1.

[0135] S4.2. Calculate the maximum transfer current of the rth flexible loop device The formula is as follows:

[0136]

[0137] Wherein: is the conjugate vector of , R H (r) is the resistance of the flexible loop device, j is the imaginary unit, X H (r) is the reactance of the flexible loop device, S H (r) is the transfer capacity of the flexible loop device, r∈1,2,...,R, and R is the number of flexible loop devices in the distribution network;

[0138] Calculate the required transfer current of the rth flexible loop device The formula is as follows:

[0139]

[0140] Wherein: and are the voltage vectors of the two power grid nodes connected by the rth flexible loop device;

[0141] Judge whether the maximum transfer current of the rth flexible loop device satisfies the following inequality with the required transfer current of the rth flexible loop device

[0142] ​

[0143] If yes, the number of times N that the rth flexible loop device can complete loop operation when the power distribution network fails s (r) add 1 and let loop success flag Flag = 0; if no, go to step S4.3;

[0144] Wherein, N s (r) initial value is 0;

[0145] S4.3. judge whether the loop success flag Flag is equal to 1;

[0146] If yes, the number of times N that the flexible loop device can complete loop operation in the power distribution network when the power distribution network fails s add 1; if no, go to step S4.4;

[0147] Wherein, N s initial value is 0;

[0148] S4.4. judge whether the flexible loop device serial number r is less than the number R of flexible loop devices in the power distribution network;

[0149] If yes, add 1 to the flexible loop device serial number r and return to step S4.2; if no, go to step S4.5;

[0150] S4.5. judge whether the power distribution network failure simulation number n is less than the preset maximum power distribution network failure simulation number N;

[0151] If yes, add 1 to the power distribution network failure simulation number n and return to step S3; if no, go to step S4.6;

[0152] S4.6. judge whether the typical day operation scene serial number m is less than the maximum power distribution network operation scene simulation number M;

[0153] If yes, add 1 to the typical day operation scene serial number m, let the power distribution network failure simulation number n equal to 1 and return to step S2; if no, record the N s (r) and N s at this time and go to step S5.

[0154] S5. calculate the total number of power distribution network operation simulation analysis, and calculate the deviation of the transfer capacity of each flexible loop device and the transfer capacity of the flexible loop device in the power distribution network according to the number of times that each flexible loop device can complete loop operation and the number of times that the flexible loop device in the power distribution network can complete loop operation, specifically including the following steps:

[0155] Calculate the total number of power distribution network operation simulation analysis S, the formula is as follows:

[0156] S = M x N

[0157] Where: M is the maximum number of simulations for the distribution network operation scenario, and N is the maximum number of simulations for the distribution network fault;

[0158] Calculate the power transfer capacity C of the flexible loop-closing device in the distribution network. s The formula is as follows:

[0159] C s =N s / S

[0160] Calculate the transfer capacity C of the r-th flexible loop-closing device. s (r), the formula is as follows:

[0161] C s (r)=N s (r) / S

[0162] The deviation between the transfer capacity of the r-th flexible loop-closing device and the transfer capacity of the flexible loop-closing devices in the distribution network is C. s (r)-C s |

[0163] S6. Evaluate the transfer capacity of each flexible loop-connected device based on the deviation between the transfer capacity of each flexible loop-connected device and the transfer capacity of the flexible loop-connected devices in the distribution network.

[0164] The power transfer capacity C of the flexible loop-closing device in the distribution network s When the value drops to the preset critical point, it means that the current capacity of the flexible loop-closing device in the distribution network is insufficient to meet the power transfer demand, and an overall capacity expansion and renovation is required.

[0165] |C s (r)-C s When the value exceeds the set threshold, it means that the r-th flexible loop closing device has a high probability of failure and needs to be upgraded. The assessment result of the transfer capacity of the r-th flexible loop closing device is: insufficient capacity, and the r-th flexible loop closing device needs to be upgraded.

[0166] |C s (r)-C s When the threshold value is less than or equal to the set threshold, the power transfer capacity assessment result of the r-th flexible loop-closing device is: the capacity is sufficient and no capacity expansion or modification is required for the r-th flexible loop-closing device.

[0167] Example 2

[0168] by Figure 4 Taking the power network structure shown as an example, Figure 4Two distributed power sources have been marked, two photovoltaic power stations are included in the new energy power station, two energy storage systems and the access position of the load user, the new energy power station can carry out output active and reactive regulation, the flexible loop device has five in total, which are connected between node 8 and node 21, node 12 and node 22, node 9 and node 15, node 25 and node 29 and node 18 and node 33, the application of the flexible loop device can compensate the voltage difference between the two power network nodes when the fault occurs, when the voltage difference between the two nodes is zero, the tie switch is connected, and when the fault is restored, the tie switch is disconnected, and the two power network nodes are not connected.

[0169] Referring to Figure 2 As shown in the figure, the present application provides a flexible loop device transfer capacity evaluation system, comprising:

[0170] A typical operation scenario acquisition module is configured to acquire a typical operation scenario set of the power distribution network.

[0171] The historical operation data of the new energy power station and the user load on each power grid node of the power distribution network is acquired, and a typical daily operation scenario of the new energy power station and the user load is established by using a scenario generation and reduction method, thereby forming a typical operation scenario set of the power distribution network.

[0172]

[0173] Wherein: is a typical daily operation scenario, m is the serial number of the typical daily operation scenario, the initial value of m is 1, and M represents the maximum simulation number of the operation scenario of the power distribution network.

[0174] An operation scenario simulation module is configured to simulate the operation scenario of the power distribution network according to the typical operation scenario set of the power distribution network, and acquire the output power of the distributed power source, the new energy power station and the energy storage system on each power grid node of the power distribution network within a typical day, specifically including the following steps:

[0175] The number of power grid nodes, the output active power, the output reactive power, the output current, the resistance, the reactance between the power grid nodes, the day-ahead predicted output active power of the new energy power station, the installed capacity of the new energy power station, the capacity state of the energy storage system, the charging efficiency of the energy storage system and the discharging efficiency of the energy storage system are acquired.

[0176] The optimization variables of the optimal power flow calculation method of the power distribution network are selected, including: the actual output active power and reactive power variables of the new energy power station, the output active power and reactive power variables of the energy storage system, the voltage of each power grid node on the power network and the current on each power network branch, the actual obtained active power and reactive power variables of the power load;

[0177] An optimization objective function for guaranteeing power supply for the load to the maximum extent is defined, and the formula is as follows:

[0178]

[0179] wherein: J is the objective function; Node represents the number of power grid framework nodes; X load,i (t) represents the actual active power obtained by the power load on the i-th power grid framework node at time t; P load,i (t) represents the active power of the load on the i-th power grid framework node at time t; Y load,i (t) represents the actual reactive power obtained by the power load on the i-th power grid framework node at time t; Q load,i (t) represents the reactive power of the load on the i-th power grid framework node at time t;

[0180] The regional power distribution network operation constraints are set, including:

[0181] The active power and reactive power balance constraints of the power system are as follows:

[0182]

[0183] wherein: X E,i (t) represents the actual output active power of the energy storage system of the i-th power grid framework node at time t; X new,i (t) represents the actual output active power of the new energy power station of the i-th power grid framework node at time t; P i,j (t) represents the active power output from the i-th power grid framework node to the j-th power grid framework node; I i,j (t) represents the current square output from the i-th power grid framework node to the j-th power grid framework node; R i,j represents the resistance between the power grid framework node j and the power grid framework node i; Y E,i (t) represents the actual output reactive power of the energy storage system of the i-th power grid framework node at time t; Y new,i (t) represents the actual output reactive power of the new energy power station of the i-th power grid framework node at time t; Q i,j (t) represents the reactive power output from the i-th power grid framework node to the j-th power grid framework node; X i,j represents the reactance between the power grid framework node j and the power grid framework node i;

[0184] The node voltage and line current constraints are as follows:

[0185]

[0186] wherein: U i (t) represents the square of the voltage of the i-th power grid framework node at time t; U j (t) represents the square of the voltage of the j-th power grid framework node at time t; Vmin(i)2 Vmax(i)2 max Ilim(i)

[0187] Pmax(i) = Pmax(i) - Pmax(i) * (1 - ηch(i)) + Pmax(i) * (1 - ηd(i))

[0188]

[0189] Pmax(i) = Pmax(i) - Pmax(i) * (1 - ηch(i)) + Pmax(i) * (1 - ηd(i)) new,i Pmax(i) = Pmax(i) - Pmax(i) * (1 - ηch(i)) + Pmax(i) * (1 - ηd(i)) new,i Pmax(i) = Pmax(i) - Pmax(i) * (1 - ηch(i)) + Pmax(i) * (1 - ηd(i))

[0190] Cmin(i) = Cmin(i) - Cmin(i) * (1 - ηch(i)) + Cmin(i) * (1 - ηd(i))

[0191]

[0192] Cmin(i) = Cmin(i) - Cmin(i) * (1 - ηch(i)) + Cmin(i) * (1 - ηd(i)) E,i Cmin(i) = Cmin(i) - Cmin(i) * (1 - ηch(i)) + Cmin(i) * (1 - ηd(i)) E,i Cmin(i) = Cmin(i) - Cmin(i) * (1 - ηch(i)) + Cmin(i) * (1 - ηd(i)) ηch(i) ηd(i) Cmin(i) = Cmin(i) - Cmin(i) * (1 - ηch(i)) + Cmin(i) * (1 - ηd(i)) Cmax(i) = Cmax(i) - Cmax(i) * (1 - ηch(i)) + Cmax(i) * (1 - ηd(i)) E,i Cmin(i) = Cmin(i) - Cmin(i) * (1 - ηch(i)) + Cmin(i) * (1 - ηd(i)) E,i Cmax(i) = Cmax(i) - Cmax(i) * (1 - ηch(i)) + Cmax(i) * (1 - ηd(i)) t Cmax(i) = Cmax(i) - Cmax(i) * (1 - ηch(i)) + Cmax(i) * (1 - ηd(i)) t N t N

[0193] According to each typical daily operation scenario in the typical operation scenario set of the distribution network, the optimal power flow calculation method is used to calculate the active power, reactive power output of the distributed power supply, new energy power station and energy storage system and the voltage of each power grid node and the branch current information of the distribution network when all the flexible loop devices and tie switches in the distribution network are disconnected, so as to obtain the output power of the distributed power supply, new energy power station and energy storage system in each power grid node of the distribution network in a typical day.

[0194] A fault simulation module is configured to simulate a power distribution network fault and obtain voltage vectors of each power grid node in the power distribution network according to output power of distributed power sources, new energy power stations and energy storage systems at each power grid node in the power distribution network within a typical day, and specifically includes the following steps:

[0195] Randomly simulate a fault occurring at different time and different location in the power distribution network, at this time, the flexible loop device does not work, and the tie switch of the power distribution network is not closed; therefore, the radial power distribution network will become two independent power grids, and the loop power distribution network will become a radial power distribution network; according to the structure of the power distribution network after the fault, define the balance, PQ, PV and other node types, and the basic elements for calculating power flow, such as the grid connection matrix and the admittance matrix, to obtain the structure parameters of the power distribution network after the fault;

[0196] According to the structure parameters of the power distribution network after the fault, and the output power of distributed power sources, new energy power stations and energy storage systems at each power grid node in the power distribution network within a typical day, the Newton-Raphson method is used to calculate the power flow of the power distribution network after the fault, to obtain the voltage amplitude and phase of each power grid node in the power distribution network, and form the voltage vector of each power grid node in the power distribution network.

[0197] A loop operation record module is configured to obtain voltage vectors of two power grid nodes connected by the flexible loop device, determine whether the flexible loop device can complete the loop operation, and record the number of times each flexible loop device can complete the loop operation and the number of times the flexible loop device in the power distribution network can complete the loop operation, and specifically includes the following steps:

[0198] Obtain the transfer capacity, resistance, reactance of the flexible loop device and the voltage vectors of the two power grid nodes connected by the flexible loop device;

[0199] 1) Let the flexible loop device sequence number r = 1, and define the loop success flag Flag = 1;

[0200] 2) Calculate the maximum transfer current of the rth flexible loop device The formula is as follows:

[0201]

[0202] Wherein: is the conjugate vector of , R H (r) is the resistance of the flexible loop device, j is the imaginary unit, X H (r) is the reactance of the flexible loop device, S H (r) is the transfer capacity of the flexible loop device, r ∈ 1, 2,..., R, and R is the number of flexible loop devices in the power distribution network;

[0203] Calculate the required rth flexible loop closing device transfer current The formula is as follows:

[0204]

[0205] Wherein: And The voltage vector of the two power grid frame nodes connected by the rth flexible loop closing device;

[0206] Determine the maximum transfer current of the rth flexible loop closing device And the required rth flexible loop closing device transfer current Whether the following inequality is satisfied:

[0207]

[0208] If satisfied, the number of times N that the rth flexible loop closing device can complete loop closing operation during power distribution network failure s (r) is added by 1, and the loop closing success flag Flag is set to 0; if not satisfied, step 3) is entered;

[0209] Wherein, N s (r) is initially 0;

[0210] 3) Determine whether the loop closing success flag Flag is equal to 1;

[0211] If yes, the number of times N that the flexible loop closing device in the power distribution network can complete loop closing operation during power distribution network failure s is added by 1; if not, step 4) is entered;

[0212] Wherein, N s is initially 0;

[0213] 4) Determine whether the flexible loop closing device serial number r is less than the number R of flexible loop closing devices in the power distribution network;

[0214] If yes, the flexible loop closing device serial number r is added by 1 and returns to step 2); if not, step 5) is entered;

[0215] 5) Determine whether the power distribution network failure simulation number n is less than the preset maximum power distribution network failure simulation number N;

[0216] If yes, the power distribution network failure simulation number n is added by 1 and returns to the failure simulation module; if not, step 6) is entered;

[0217] 6) Determine whether the typical day operation scenario serial number m is less than the maximum power distribution network operation scenario simulation number M;

[0218] If yes, the typical day operation scenario sequence number m is added 1, the power distribution network fault simulation number n is equal to 1 and the operation scenario simulation module is returned; if no, the N at this time is recorded s (r) and N s And enter the deviation calculation module.

[0219] The deviation calculation module is used for calculating the total number of power distribution network operation simulation analysis, and calculating the transfer capacity of each flexible loop device and the deviation of the transfer capacity of the flexible loop device in the power distribution network according to the number of times that each flexible loop device can complete loop operation and the number of times that the flexible loop device in the power distribution network can complete loop operation, and specifically includes the following steps:

[0220] The total number of power distribution network operation simulation analysis S is calculated, and the formula is as follows:

[0221] S = M × N

[0222] Wherein, M is the maximum simulation number of power distribution network operation scenarios, and N is the maximum simulation number of power distribution network faults;

[0223] The transfer capacity C of the flexible loop device in the power distribution network is calculated s , and the formula is as follows:

[0224] C s = N s / S

[0225] The transfer capacity C s (r) of the rth flexible loop device is calculated, and the formula is as follows:

[0226] C s (r) = N s (r) / S

[0227] The deviation of the transfer capacity of the rth flexible loop device and the transfer capacity of the flexible loop device in the power distribution network is C s (r)-C s |.

[0228] The evaluation module is used for evaluating the transfer capacity of each flexible loop device according to the deviation of the transfer capacity of each flexible loop device and the transfer capacity of the flexible loop device in the power distribution network;

[0229] When the transfer capacity C s of the flexible loop device in the power distribution network drops to a preset critical point, it means that the capacity of the current flexible loop device in the power distribution network is difficult to guarantee the demand of power transfer, and overall capacity expansion needs to be carried out;

[0230] |C s (r)-C s| Greater than the set threshold value means that the rth flexible ring device has a higher failure probability, and needs to be capacity-increased and reconstructed, and the transfer capacity evaluation result of the rth flexible ring device is: insufficient capacity, and the rth flexible ring device needs to be capacity-increased and reconstructed;

[0231] |C s (r)-C s | Less than or equal to the set threshold value means that the rth flexible ring device has sufficient capacity, and does not need to be capacity-increased and reconstructed.

[0232] Embodiment 3

[0233] Please refer to Figure 3 The present application also provides an electronic device 100 for implementing the flexible ring device transfer capacity evaluation method. The electronic device 100 comprises a memory 101, at least one processor 102, a computer program 103 stored in the memory 101 and executable on the at least one processor 102, and at least one communication bus 104.

[0234] The memory 101 can be used to store the computer program 103, and the processor 102 can implement the steps of the flexible ring device transfer capacity evaluation method by running or executing the computer program stored in the memory 101 and calling the data stored in the memory 101. The memory 101 can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required by a function (such as a sound playing function, an image playing function, etc.), and the like; and the data storage area can store data (such as audio data) created according to the use of the electronic device 100, etc. In addition, the memory 101 can include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, at least one disk storage device, a flash memory device, or other non-volatile solid-state storage device.

[0235] The at least one processor 102 can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, etc. The processor 102 can be a microprocessor or can also be any conventional processor, etc., which is the control center of the electronic device 100 and connects all parts of the electronic device 100 through various interfaces and lines.

[0236] The memory 101 in the electronic device 100 stores a plurality of instructions to implement a flexible loop device transfer capacity evaluation method, and the processor 102 can execute the plurality of instructions to implement:

[0237] S1. Obtain a set of typical operation scenarios of a power distribution network;

[0238] S2. Perform power distribution network operation scenario simulation according to the set of typical operation scenarios of the power distribution network, and obtain the output power of the distributed power supply, new energy power station and energy storage system on each power grid node of the power distribution network within a typical day;

[0239] S3. Perform power distribution network fault simulation, and obtain the voltage vector of each power grid node in the power distribution network according to the output power of the distributed power supply, new energy power station and energy storage system on each power grid node of the power distribution network within a typical day;

[0240] S4. Obtain the voltage vectors of the two power grid nodes connected by the flexible loop device, determine whether the flexible loop device can complete the loop operation, and record the number of times each flexible loop device can complete the loop operation and the number of times the flexible loop device in the power distribution network can complete the loop operation;

[0241] S5. Calculate the total number of power distribution network operation simulation analysis, and calculate the deviation of the transfer capacity of each flexible loop device and the transfer capacity of the flexible loop device in the power distribution network according to the number of times each flexible loop device can complete the loop operation and the number of times the flexible loop device in the power distribution network can complete the loop operation;

[0242] S6. According to the deviation of the transfer capacity of each flexible loop device and the transfer capacity of the flexible loop device in the power distribution network, evaluate the transfer capacity of each flexible loop device.

[0243] Embodiment 4

[0244] The modules / units integrated in the electronic device 100, if implemented in the form of software functional units and sold or used as independent products, can be stored in a computer-readable storage medium. Based on such understanding, all or part of the processes in the above-mentioned embodiment methods can also be instructed by a computer program to relevant hardware to complete, and the computer program can be stored in a computer-readable storage medium. When the processor executes the computer program, the steps of each method embodiment described above can be implemented. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or some intermediate forms. The computer-readable medium can include any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, and read-only memory (ROM).

[0245] Those skilled in the art will appreciate that embodiments of the application can be supplied as a method, a system, or a computer program product. Therefore, the application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code.

[0246] The application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as the combination of flows and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the computer or other programmable data processing apparatus produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that carries out the functions specified in one or more blocks.

[0247] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including instruction apparatus that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 one or more flows and / or blocks Figure 1 an apparatus that carries out the functions specified in one or more blocks.

[0248] These computer program instructions can also be loaded into computer or other programmable data processing devices, so that a series of operational steps are performed on the computer or other programmable data processing devices to generate computer-implemented processes, thus the instructions executed on the computer or other programmable data processing devices provide the function of implementing the processes specified in the flowcharts Figure 1 one flow or multiple flows and / or the functions specified in the block Figure 1 one flow or multiple flows and / or the functions specified in the block

[0249] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand: the specific embodiments of the present application can still be modified or replaced by the equivalent, without departing from the spirit and scope of the present application, any modification or equivalent replacement, which should be covered within the protection scope of the claims of the present application.

Claims

1. A method for evaluating the transfer capacity of a flexible loop-closing device, characterized in that, Includes the following steps: S1. Obtain a set of typical operating scenarios for the power distribution network; S2. Simulate the operation scenario of the distribution network based on the typical operation scenario set of the distribution network, and obtain the output power of distributed power sources, new energy power stations and energy storage systems on each power grid node of the distribution network during a typical day; S3. Perform distribution network fault simulation, and obtain the voltage vector of each power grid node in the distribution network based on the output power of distributed power sources, new energy power stations and energy storage systems on each power grid node in a typical day; S4. Obtain the voltage vectors of the two power grid nodes connected by the flexible loop closing device, determine whether the flexible loop closing device can complete the loop closing operation, and record the number of times each flexible loop closing device can complete the loop closing operation and the number of times the flexible loop closing device in the distribution network can complete the loop closing operation. S5. Calculate the total number of simulation analyses of the distribution network operation, and calculate the deviation between the transfer capacity of each flexible loop-closing device and the transfer capacity of the flexible loop-closing devices in the distribution network based on the number of times each flexible loop-closing device can complete the loop-closing operation and the number of times the flexible loop-closing devices in the distribution network can complete the loop-closing operation. S6. Evaluate the transfer capacity of each flexible loop-connected device based on the deviation between the transfer capacity of each flexible loop-connected device and the transfer capacity of the flexible loop-connected devices in the distribution network. The steps of calculating the total number of distribution network operation simulation analyses, and calculating the deviation between the transfer capacity of each flexible loop-closing device and the transfer capacity of the flexible loop-closing devices within the distribution network, based on the number of times each flexible loop-closing device can complete a loop-closing operation and the number of times the flexible loop-closing devices within the distribution network can complete a loop-closing operation, specifically include: The total number of simulation analyses, S, for the power distribution network operation is calculated using the following formula: Where N is the preset maximum number of simulations for distribution network faults, and M is the maximum number of simulations for distribution network operation scenarios; Calculate the power transfer capacity of flexible loop-closing devices in the distribution network The formula is as follows: in, The number of times a flexible loop-closing device in a distribution network can complete a loop-closing operation; Calculate the transfer capacity of the r-th flexible loop-closing device. The formula is as follows: in, Let r be the number of times the flexible loop-closing device can complete the loop-closing operation; The deviation between the transfer capacity of the r-th flexible loop-closing device and the transfer capacity of the flexible loop-closing devices in the distribution network is: ; The step of evaluating the power transfer capacity of each flexible loop-connected device based on the deviation between the power transfer capacity of each flexible loop-connected device and the power transfer capacity of flexible loop-connected devices in the distribution network specifically includes: The deviation between the transfer capacity of the r-th flexible loop-closing device and the transfer capacity of the flexible loop-closing devices in the distribution network. Compare with a set threshold; When the threshold is exceeded, the power transfer capacity assessment result of the r-th flexible loop-closing device is: insufficient capacity, and the r-th flexible loop-closing device needs to be upgraded. When the threshold value is less than or equal to the set threshold, the power transfer capacity assessment result of the r-th flexible loop-closing device is: the capacity is sufficient and no capacity expansion or modification is required for the r-th flexible loop-closing device.

2. The method for evaluating the transfer capacity of a flexible loop-closing device according to claim 1, characterized in that, The steps for obtaining a set of typical operating scenarios for a power distribution network specifically include: Acquire historical operating data of new energy power plants and user loads at various power grid nodes in the distribution network; Based on historical operating data of renewable energy power plants and user loads at various power grid nodes in the distribution network, typical daily operating scenarios for renewable energy power plants and user loads are established using scenario generation and reduction methods, forming a set of typical operating scenarios for the distribution network. in: For a typical daily operation scenario, m is the sequence number of the typical daily operation scenario, the initial value of m is 1, and M represents the maximum number of simulations for the distribution network operation scenario.

3. The method for evaluating the transfer capacity of a flexible loop-closing device according to claim 2, characterized in that, The step of simulating distribution network operation scenarios based on a set of typical distribution network operation scenarios to obtain the output power of distributed power sources, new energy power stations, and energy storage systems on each power grid node of the distribution network during a typical day specifically includes: Obtain the number of power grid nodes, the output active power, output reactive power, output current, resistance, and reactance between power grid nodes, the day-ahead predicted output active power of new energy power plants, the installed capacity of new energy power plants, the capacity status of energy storage systems, the charging efficiency of energy storage systems, and the discharging efficiency of energy storage systems. The optimization variables for selecting the optimal power flow calculation method for the distribution network include: the actual output active and reactive power variables of the new energy power plant, the output active and reactive power variables of the energy storage system, the voltage of each power grid node on the power network and the current on each power network branch, and the actual active and reactive power variables obtained by the power load. The objective function for maximizing power supply to the load is defined as follows: Where: J is the objective function; Node represents the number of nodes in the power grid; express t Time of the first i The actual active power obtained by the electrical load at each node of the power grid; This represents the active power of the load at the i-th node of the power grid at time t; express t Time of the first i The actual reactive power obtained by the electrical load at each node of the power grid; This represents the reactive power of the load at the i-th node of the power grid at time t; Set regional power distribution network operation constraints; Based on the typical daily operating scenario of the distribution network, the optimal power flow calculation method is used to calculate the active power and reactive power output of distributed power sources, new energy power plants and energy storage systems when all flexible loop devices and tie switches in the distribution network are disconnected, as well as the voltage and branch current information of each power grid node in the distribution network. In this way, the output power of distributed power sources, new energy power plants and energy storage systems on each power grid node in the distribution network during a typical day is obtained. Specifically, the regional power distribution network operation constraints include: The active and reactive power balance constraints of a power system are given by the following formula: in: Indicates the first i Each power grid node is t The actual output active power of the energy storage system at all times; Indicates the first i Each power grid node is t The actual active power output of the new energy power station at all times; Indicates the first i The power grid node to the first j The active power output of each power grid node; Indicates the first i The power grid node to the first j The square of the current output by each power grid node; Represents power grid nodes j With power grid nodes i The resistance between; Indicates the first i Each power grid node is t The actual reactive power output of the energy storage system at any given time; Indicates the first i Each power grid node is t The actual reactive power output of the new energy power station at any given time; Indicates the first i The power grid node to the first j The reactive power output of each power grid node; Represents power grid nodes j With power grid nodes i The reactance between them; The constraints on node voltage and line current are given by the following formula: in: Indicates in t Power grid nodes at all times i The square of the voltage; Indicates in t Power grid nodes at all times j The square of the voltage; This represents the square of the lower limit of the voltage at a power grid node. This represents the square of the upper limit of the voltage at a power grid node; Indicates the square of the maximum current that can pass through the branch; The power output constraint of new energy sources is given by the following formula: in: Indicates the first i Each power grid node is t The maximum active power output of the Shike New Energy Power Station is currently predicted. Indicates the first i The installed capacity of new energy power plants at each power grid node; The energy balance constraint of an energy storage system is given by the following formula: in: Indicates the first i Energy storage system at each power grid node The capacity status at any given moment; Indicates a time interval; Indicates the first i Energy storage system at each power grid node t The capacity status at any given moment; Indicates the first i Charging efficiency of energy storage systems on individual power grid nodes; Indicates the first i Discharge efficiency of energy storage systems at individual power grid nodes; Indicates the first i The lower limit of the capacity status of energy storage systems on each power grid node; Indicates the first i The upper limit of the capacity status of energy storage systems on each power grid node; Indicates the first i The initial capacity of an energy storage system on a power grid node in a typical day; Indicates the first i The final capacity of an energy storage system on a power grid node in a typical day; This indicates a typical day with a total of Each point in time.

4. The method for evaluating the transfer capacity of a flexible loop-closing device according to claim 1, characterized in that, The steps of simulating distribution network faults and obtaining the voltage vector of each power grid node in the distribution network based on the output power of distributed power sources, new energy power plants, and energy storage systems on each power grid node within a typical day specifically include: Randomly simulate the fault occurrence of the distribution network at different times and locations to obtain the distribution network structure parameters after the fault occurs; Based on the distribution network structure parameters after the fault, and the output power of distributed power sources, new energy power stations and energy storage systems on each power grid node of the distribution network during a typical day, the power flow of the distribution network after the fault is calculated, and the voltage amplitude and phase of each power grid node in the distribution network are obtained. The voltage vector of each power grid node in the distribution network is formed based on the voltage amplitude and phase of each power grid node in the distribution network.

5. The method for evaluating the transfer capacity of a flexible loop-closing device according to claim 2, characterized in that, The steps of obtaining the voltage vectors of the two power grid nodes connected to the flexible loop closing device, determining whether the flexible loop closing device can complete the loop closing operation, and recording the number of times each flexible loop closing device can complete the loop closing operation and the number of times the flexible loop closing device in the distribution network can complete the loop closing operation specifically include: Obtain the transfer capacity, resistance, reactance, and voltage vector of the two connected power grid nodes of the flexible loop-connected device; S4.

1. Let the sequence number r of the flexible loop closing device be 1, and define the loop closing success flag Flag = 1; S4.

2. Calculate the maximum transfer current of the r-th flexible loop closing device. The formula is as follows: in: for The conjugate vector, Let j be the resistance of the flexible loop-closure device, and j be the imaginary part in units. For the reactance of the flexible loop-closing device, For the transfer capacity of the flexible loop-closing device, R represents the number of flexible loop-closing devices in the distribution network; Calculate the required transfer current of the r-th flexible loop-closing device. The formula is as follows: in: and For the first r The voltage vector of two power grid nodes connected by a flexible loop-closing device; Determine the maximum transfer current of the r-th flexible loop closing device. The transfer current of the required r-th flexible loop-closing device Does it satisfy the following inequality: If satisfied, then the number of times the r-th flexible loop-closing device can complete the loop-closing operation during a distribution network fault is [number missing]. Add 1, and set the success flag Flag to 1; if not satisfied, set Flag to 0; proceed to step S4.3; in, The initial value is 0; S4.

3. Determine if the success flag for loop closure is equal to 1; If so, then during a distribution network fault, the number of times the flexible loop-closing device within the distribution network can complete the loop-closing operation is... If not, proceed to step S4.4; in, The initial value is 0; S4.

4. Determine whether the serial number r of the flexible loop closing device is less than the number R of flexible loop closing devices in the distribution network; If yes, increment the flexible loop closing device number r by 1 and return to step S4.2; if no, proceed to step S4.

5. S4.

5. Determine whether the number of times n is simulated for a distribution network fault is less than the preset maximum number of times N is simulated for a distribution network fault; If yes, increment the number of power grid fault simulations n by 1 and return to step S3; otherwise, proceed to step S4.

6. S4.

6. Determine whether the sequence number m of the typical daily operation scenario is less than the maximum number of simulations M of the distribution network operation scenario; If yes, increment the typical daily operation scenario number m by 1, set the number of distribution network fault simulations n to 1, and return to step S2; if no, record the current state. as well as Then proceed to step S5.

6. A flexible loop-closing device transfer capacity assessment system, characterized in that, include: The typical operation scenario acquisition module is used to acquire a set of typical operation scenarios for the power distribution network. The operation scenario simulation module is used to simulate the operation scenario of the distribution network based on the typical operation scenario set of the distribution network, and to obtain the output power of distributed power sources, new energy power stations and energy storage systems on each power grid node of the distribution network during a typical day. The fault simulation module is used to simulate faults in the distribution network and obtain the voltage vector of each power grid node in the distribution network based on the output power of distributed power sources, new energy power plants and energy storage systems on each power grid node in a typical day. The loop closing operation recording module is used to obtain the voltage vectors of the two power grid nodes connected by the flexible loop closing device, determine whether the flexible loop closing device can complete the loop closing operation, and record the number of times each flexible loop closing device can complete the loop closing operation and the number of times the flexible loop closing device in the distribution network can complete the loop closing operation. The deviation calculation module is used to calculate the total number of simulation analyses of the distribution network operation, and to calculate the deviation between the transfer capacity of each flexible loop-closing device and the transfer capacity of the flexible loop-closing devices in the distribution network, based on the number of times each flexible loop-closing device can complete the loop-closing operation and the number of times the flexible loop-closing devices in the distribution network can complete the loop-closing operation. The evaluation module is used to evaluate the power transfer capacity of each flexible loop device based on the deviation between the power transfer capacity of each flexible loop device and the power transfer capacity of flexible loop devices in the distribution network. The steps of calculating the total number of distribution network operation simulation analyses, and calculating the deviation between the transfer capacity of each flexible loop-closing device and the transfer capacity of the flexible loop-closing devices within the distribution network, based on the number of times each flexible loop-closing device can complete a loop-closing operation and the number of times the flexible loop-closing devices within the distribution network can complete a loop-closing operation, specifically include: The total number of simulation analyses, S, for the power distribution network operation is calculated using the following formula: Where N is the preset maximum number of simulations for distribution network faults, and M is the maximum number of simulations for distribution network operation scenarios; Calculate the power transfer capacity of flexible loop-closing devices in the distribution network The formula is as follows: in, The number of times a flexible loop-closing device in a distribution network can complete a loop-closing operation; Calculate the transfer capacity of the r-th flexible loop-closing device. The formula is as follows: in, Let r be the number of times the flexible loop-closing device can complete the loop-closing operation; The deviation between the transfer capacity of the r-th flexible loop-closing device and the transfer capacity of the flexible loop-closing devices in the distribution network is: ; The step of evaluating the power transfer capacity of each flexible loop-connected device based on the deviation between the power transfer capacity of each flexible loop-connected device and the power transfer capacity of flexible loop-connected devices in the distribution network specifically includes: The deviation between the transfer capacity of the r-th flexible loop-closing device and the transfer capacity of the flexible loop-closing devices in the distribution network. Compare with a set threshold; When the threshold is exceeded, the power transfer capacity assessment result of the r-th flexible loop-closing device is: insufficient capacity, and the r-th flexible loop-closing device needs to be upgraded. When the threshold value is less than or equal to the set threshold, the power transfer capacity assessment result of the r-th flexible loop-closing device is: the capacity is sufficient and no capacity expansion or modification is required for the r-th flexible loop-closing device.

7. An electronic device, characterized in that, It includes a processor and a memory, the processor being used to execute a computer program stored in the memory to implement a method for evaluating the transfer capacity of a flexible loop-closing device as described in any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one instruction, which, when executed by a processor, implements a method for evaluating the transfer capability of a flexible loop-closing device as described in any one of claims 1 to 5.

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