Method and device for power frequency inference source live line measurement for mutual inductance line zero-sequence impedance parameter

Abstract

A method for measuring the zero-sequence impedance parameters of a mutual induction line by using a power frequency interference source live, in which a certain line in the mutual induction line group is powered off in sequence, and one end of the power failure line is short-circuited with three phases to ground, and the other end is short-circuited with three phases before measurement Its induced voltage; measure the zero-sequence voltage drop and zero-sequence current on other operating lines at the same time; use GPS technology to synchronously sample the zero-sequence voltage and zero-sequence current signals on the mutual inductance line to obtain the zero-sequence voltage on the mutual inductance line and zero-sequence current data; the data of each measuring point is summarized to the central computer; then the least squares method is used to solve the algebraic equations, differential equations or integral equations to obtain the zero-sequence impedance parameters of the mutual inductance circuit; the device of the present invention consists of a GPS antenna It is composed of OEM board, signal input terminals, signal transmitter, embedded DSP synchronous data acquisition card, output card, relay group, relay output interface, embedded PC card, power supply card, etc.

Description

technical field [0001] The invention belongs to the technical field of parameter measurement of electric power system transmission lines, in particular to a method and device for measuring the zero-sequence impedance parameters of a mutual inductance line with electricity. Background technique [0002] With the development of the scale of the power system, there are more and more outgoing lines in power plants (substations), and there are more and more mutual inductance lines. [0003] The zero-sequence impedance of the line with mutual inductance will affect the fault state of the line, especially the magnitude of the zero-sequence current, which has a great impact on the zero-sequence current protection; because the zero-sequence impedance of the line with mutual inductance is affected by many factors, the direction of the line, the zero-sequence The grounding resistivity of the sequence current flowing through the area, etc.; the theoretical calculation value cannot meet ...

AI Technical Summary

Problems solved by technology

[0003] The zero-sequence impedance of the line with mutual inductance will affect the fault state of the line, especially the magnitude of the zero-sequence current, which has a great impact on the zero-sequence current protection; because the zero-sequence impedance of the line with mutual inductance is affected by many factors, the direction of the line, the zero-sequence The grounding resistivity of the sequence current flowing through the area, etc.; the theoretical calculation value cannot meet the accuracy requirements for the calculation of the relay protection setting value. If the calculation value is used as the basis for the setting calculation, the protection will refuse to operate or malfunction when the system fails. This directly threatens the safe and stable operation of the system; therefore, in the electric power industry standard of the People's Republic of China, the "220kV-500kV power grid The regulations on electric protection setting point out that: the zero-sequence impedance of overhead lines and cables, and other parameters that have a greater impact on relay protection should use measured values.

[0004] The traditional methods for determining the zero-sequence parameters of transmission lines include formula calculation method and blackout measurement method; because the calculation formula involves inaccurate parameters such as earth resistivity, the calculation result of the formula is inaccurate

[0005] The method of measuring the zero-sequence impedance parameters of the mutual inductance line with the power outage measurement method requires a power outage of the tested line; it is often impossible to measure the complete power outage of the mutual inductance line; The amount of equipment and workload is too large to bear, and the simultaneity of the measurement cannot be guaranteed; therefore, it is urgently needed by the power system operation department to seek a live measurement method for the zero-sequence impedance parameters of the mutual inductance line and to develop a corresponding test system. Has important theoretical value, and has great economic and social benefits

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