Method and device for determining additional impedance

Abstract

The embodiments of the invention provide a method and a device for determining additional impedance, which relate to the field of power systems. Through the method and the device, the additional impedance of a crisscross disconnection spanning fault of a double-circuit transmission line can be determined. The method includes the following steps: acquiring a sequence voltage model of a first fault point, a sequence voltage model of a second fault point and a sequence voltage model of a third fault point, wherein the first fault point and the second fault point are generated by disconnection of a first circuit of a transmission line, and the third fault point is generated by spanning connection of at least one disconnected phase of the first circuit of the transmission line to at least one phase of a second circuit; determining a sequence voltage network model according to the sequence voltage model of the first fault point, the sequence voltage model of the second fault point and the sequence voltage model of the third fault point; acquiring a fault topology; determining a fault point admittance matrix according to the fault topology; acquiring a phase fault boundary condition model according to the fault point admittance matrix; and determining the additional impedance according to the sequence voltage network model and the phase fault boundary condition model.

Description

technical field [0001] The present application relates to the field of power systems, in particular to a method and device for determining additional impedance. Background technique [0002] With the development of the economy, the power grid continues to expand, and the distribution of transmission lines is more dense, which makes the possibility of crossing and crossing faults of two transmission lines intensified. For example, if figure 1 As shown, one of the first transmission lines D1D2 is disconnected and then falls to the second transmission line D3D4, causing a short circuit, the B phase and C phase of the first transmission line D1D2 are disconnected, and the disconnection generates fault points K1 and Fault point K2, phase B of K1 and phase C of K2 fall to the same place of the second transmission line D3D4, and a short circuit occurs to generate fault point K3, where phase B of fault point K1 is connected to phase A of fault point K3 and is not grounded , phase ...

AI Technical Summary

Problems solved by technology

However, the fault boundary conditions of the crossover fault of two-circuit transmission lines are complex. For the fault of multi-point crossover at the same crossover position of two-circuit transmission lines, the traditional analysis method is not applicable, and it is impossible to calculate the crossover fault of two-circuit transmission lines. Additional impedance across the fault

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