CN-122017668-A - Calculation method and system for short-circuit current of network-structured energy storage access system based on voltage dynamic partition

CN122017668ACN 122017668 ACN122017668 ACN 122017668ACN-122017668-A

Abstract

The invention discloses a method and a system for calculating short-circuit current of a grid-structured energy storage access system based on voltage dynamic partitioning, and belongs to the technical field of power systems. The method comprises setting zero, positive and negative sequence current-cutting voltages and positive and negative sequence output current initial values of dividing nodes for a network-structured energy storage access system, and calculating the dividing nodes Voltage of (2) And (d) Subnet voltage of individual partitions According to the above And The method comprises the steps of updating positive and negative sequence output current components, converting the updated positive and negative sequence output current components in each partition of the voltage dynamic partition into equivalent output currents of the partition sub-network, and determining short-circuit currents transferred to a main power grid by a network-structured energy storage access system. The method can calculate the short-circuit current level of the network-structured energy storage access system efficiently, is beneficial to identifying faults more accurately and triggering protection actions more timely and effectively, and accordingly improves the safety and stability of the network-structured energy storage system under fault working conditions.

Inventors

TANG XIAOJUN
Huo qidi
WANG ZIQI
GAO WENMAN
ZHU SHAOXUAN
XIE YAN
CHEN DEZHI

Assignees

中国电力科学研究院有限公司

Dates

Publication Date: 20260512
Application Date: 20260114

Claims (10)

1. A calculation method of a network-structured energy storage access system short-circuit current based on voltage dynamic partitioning is characterized by comprising the following steps: zero, positive and negative sequence current interruption voltages and positive and negative sequence output current initial values of given dividing nodes of the network-structured energy storage access system; calculating a current matrix of each partition of the voltage dynamic partition based on zero, positive and negative sequence current-cutting voltages and positive and negative sequence output current initial values of the partition nodes, and determining the dynamic partition based on the current matrix and then partitioning the nodes Voltage of (2) And (d) Subnet voltage of individual partitions ; According to the described And Updating positive and negative sequence output current components; Converting the updated positive and negative sequence output current components in each partition of the voltage dynamic partition into equivalent output currents of the partition sub-network; Judging whether the errors of the current positive and negative sequence cutoff voltages and the previous positive and negative sequence cutoff voltages meet the precision requirement, if so, determining positive and negative sequence currents transmitted to a main power grid by a grid-structured energy storage access system based on the equivalent output currents; and the positive and negative sequence current forms a short circuit current of the net type energy storage access system.
2. The method according to claim 1, wherein the calculation formula for calculating the current matrix of each of the voltage dynamic partitions is as follows: Wherein, the And After representing dynamic partitioning, nodes are partitioned Voltage sum of (2) Sub-network voltages of the individual partitions; And Representing partitioning nodes Injecting equivalent current into a power grid; And After the dynamic partition is represented, Node is divided to axle Voltage sum of (2) Admittance matrix of each partition; And After the dynamic partition is represented, Node is divided to axle Voltage sum of (2) The admittance matrix of each partition, Represented as a net-like stored energy internal potential.
3. The computing method of claim 1, wherein after the dynamic partitioning, nodes are partitioned Voltage of (2) And (d) Subnet voltage of individual partitions The calculation formula of (2) is as follows: Wherein, the , , Respectively expressed as m-partition node admittance matrix, current matrix and d-axis lower partition node Admittance matrix of (a).
4. The computing method according to claim 1, wherein the computing formula for determining positive and negative sequence currents transferred to the main grid by the grid-formation energy storage access system is as follows: Wherein, the And Respectively represent positive and negative sequence currents An axis component of the optical fiber, And Representing a functional relationship to respectively describe the voltages of all the subareas after dynamic division Short-circuit current with positive sequence Negative sequence short circuit current The correspondence between them.
5. A voltage dynamic partition-based grid-formation type energy storage access system short-circuit current computing system, which is characterized by comprising: The given unit is used for giving zero, positive and negative sequence current-cutting voltages and positive and negative sequence output current initial values of the dividing nodes for the network-structured energy storage access system; A first calculation unit for calculating current matrixes of each partition of the voltage dynamic partition based on zero, positive and negative sequence current-cutting voltages and positive and negative sequence output current initial values of the partition nodes, and determining the partition nodes after dynamic partition based on the current matrixes Voltage of (2) And (d) Subnet voltage of individual partitions ; A second calculation unit for calculating the following parameters And Updating positive and negative sequence output current components; The third calculation unit is used for converting the updated positive and negative sequence output current components in each partition of the voltage dynamic partition into equivalent output currents of the partition sub-network; The output unit is used for judging whether the errors of the current positive and negative sequence cutoff voltage and the last positive and negative sequence cutoff voltage meet the precision requirement, and if so, determining positive and negative sequence currents transmitted to the main power grid by the grid-structured energy storage access system based on the equivalent output current; and the positive and negative sequence current forms a short circuit current of the net type energy storage access system.
6. The computing system of claim 5, wherein the current matrix for each of the voltage dynamic partitions is calculated as follows: Wherein, the And After representing dynamic partitioning, nodes are partitioned Voltage sum of (2) Sub-network voltages of the individual partitions; And Representing partitioning nodes Injecting equivalent current into a power grid; And After the dynamic partition is represented, Node is divided to axle Voltage sum of (2) Admittance matrix of each partition; And After the dynamic partition is represented, Node is divided to axle Voltage sum of (2) The admittance matrix of each partition, Represented as a net-like stored energy internal potential.
7. The computing system of claim 5, wherein after the dynamic partitioning, nodes are partitioned Voltage of (2) And (d) Subnet voltage of individual partitions The calculation formula of (2) is as follows: Wherein, the , , Respectively expressed as m-partition node admittance matrix, current matrix and d-axis lower partition node Admittance matrix of (a).
8. The computing system of claim 5, wherein the calculation formula for determining positive and negative sequence currents delivered to the main grid by the grid energy storage access system is as follows: Wherein, the And Respectively represent positive and negative sequence currents An axis component of the optical fiber, And Representing a functional relationship to respectively describe the voltages of all the subareas after dynamic division Short-circuit current with positive sequence Negative sequence short circuit current The correspondence between them.
9. A computer device, comprising: one or more processors; a processor for executing one or more programs; The method of any of claims 1-4 is implemented when the one or more programs are executed by the one or more processors.
10. A computer readable storage medium, characterized in that a computer program is stored thereon, which computer program, when executed, implements the method according to any of claims 1-4.

Description

Calculation method and system for short-circuit current of network-structured energy storage access system based on voltage dynamic partition Technical Field The invention relates to the technical field of power systems, in particular to a method and a system for calculating short-circuit current of a grid-structured energy storage access system based on voltage dynamic partitioning. Background In operation of the power system, a short-circuit fault is one of the most common faults, and the short-circuit current generated by the short-circuit fault can have serious influence and consequences on the safe and stable operation of the power system. The network-structured energy storage (GFESS) depends on a Virtual Synchronous Generator (VSG) control strategy, and becomes a key for supporting the stable operation of a novel power system. The dynamic support system can actively simulate the inertia response characteristic of the synchronous generator, not only provides dynamic support for a high-proportion new energy power grid, but also plays a core power supply role in application scenes such as off-grid micro-grid, black start and the like. However, in the existing method for calculating the short-circuit current of the fault point after the new energy/energy storage station is accessed to the system, it is difficult to precisely quantify the influence degree of the change of the control parameters on the short-circuit current. Disclosure of Invention Aiming at the problems, the invention provides a method for calculating the short-circuit current of a network-structured energy storage access system based on voltage dynamic partitioning, which comprises the following steps: zero, positive and negative sequence current interruption voltages and positive and negative sequence output current initial values of given dividing nodes of the network-structured energy storage access system; calculating a current matrix of each partition of the voltage dynamic partition based on zero, positive and negative sequence current-cutting voltages and positive and negative sequence output current initial values of the partition nodes, and determining the dynamic partition based on the current matrix and then partitioning the nodes Voltage of (2)And (d)Subnet voltage of individual partitions; According to the describedAndUpdating positive and negative sequence output current components; Converting the updated positive and negative sequence output current components in each partition of the voltage dynamic partition into equivalent output currents of the partition sub-network; Judging whether the errors of the current positive and negative sequence cutoff voltages and the previous positive and negative sequence cutoff voltages meet the precision requirement, if so, determining positive and negative sequence currents transmitted to a main power grid by a grid-structured energy storage access system based on the equivalent output currents; and the positive and negative sequence current forms a short circuit current of the net type energy storage access system. Optionally, a calculation formula for calculating the current matrix of each partition of the voltage dynamic partition is as follows: Wherein, the AndAfter representing dynamic partitioning, nodes are partitionedVoltage sum of (2)Sub-network voltages of the individual partitions; And Representing partitioning nodesInjecting equivalent current into a power grid; And After the dynamic partition is represented,Node is divided to axleVoltage sum of (2)Admittance matrix of each partition; And After the dynamic partition is represented,Node is divided to axleVoltage sum of (2)The admittance matrix of each partition,Represented as a net-like stored energy internal potential. Optionally, after the dynamic partitioning, the nodes are partitionedVoltage of (2)And (d)Subnet voltage of individual partitionsThe calculation formula of (2) is as follows: Wherein, the ,,Respectively expressed as m-partition node admittance matrix, current matrix and d-axis lower partition nodeAdmittance matrix of (a). Optionally, a calculation formula for determining positive and negative sequence currents transferred to the main power grid by the grid-structured energy storage access system is as follows: Wherein, the AndRespectively represent positive and negative sequence currentsAn axis component of the optical fiber,AndRepresenting a functional relationship to respectively describe the voltages of all the subareas after dynamic divisionShort-circuit current with positive sequenceNegative sequence short circuit currentThe correspondence between them. In still another aspect, the present invention further provides a calculation system for short-circuit current of a network-structured energy storage access system based on voltage dynamic partitioning, including: The given unit is used for giving zero, positive and negative sequence current-cutting voltages and positive and negative sequence output curr