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

Abstract

A method use line-frequency disturb the zero-sequence impedance parameter of resource charge measure mutual inductance circuit, cuts the power of a certain circuit in the mutual inductance circuit in order, puts one three-phase of the power cut circuit to earth, measures the induction voltage of the other one after it is in short-circuit; at the same time measures the zero-sequence voltage pressure loss and zero-sequence current in the other run circuit; uses the GPS technology sample the zero-sequence voltage, zero-sequence current in the mutual inductance circuit in-phase, gets the zero-sequence voltage, zero-sequence current data in the mutual inductance circuit; collects the data of each measurement point to the center computer; gets the zero-sequence impedance parameter of the mutual inductance circuit by using the least square law solute the algebraic equations, differential equations or integral equations; this equipment is composed of GPS antenna, signal input connection interface, signal transducer, embedded DPS synchromesh data collection card, launch amount card, relay group, embed PC card, the electrical source card.

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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