T-shaped transmission line zero-sequence resistance parameter live line measurement method and device

Abstract

The zero-sequence impedance parameter measure method of the T type electric transmission line, the method lets the load current provide the zero-sequence current for measurement by cutting the single-phase switch in a certain branch of T type electric transmission line to make run without phase, then resumes the normal run in 0.5 second to 1 second. Uses the GPS technology realize the multi-terminal zero-sequence voltage, zero-sequence current synchromesh collection of T type electric transmission line; collects the data of each measurement point to the center computer by using the modem or Ethernet network; 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 and OEM board, signal input connection interface, signal transducer, embedded DPS synchromesh data collection card, launch amount card, relay group, relay group input interface, embed PC card, the electrical source card, electrical source signal bus motherboard.

Description

technical field [0001] The invention belongs to the technical field of parameter measurement of power system transmission lines, in particular to a method and a measurement device for live-measuring the zero-sequence parameters of a T-type transmission line. Background technique [0002] With the development of the scale of the power system, there are more and more outgoing lines of power plants (substations), and more and more T-connection transmission lines; [0003] The zero-sequence impedance of the T-type transmission line 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 T-type transmission line is affected by many factors, the direction of the line , the grounding resistivity of the zero-sequence current flow area, etc.; the theoretical calculation value cannot meet the accuracy requirements for the calculation of t...

AI Technical Summary

Problems solved by technology

[0003] The zero-sequence impedance of the T-type transmission line 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 T-type transmission line is affected by many factors, the direction of the line , the grounding resistivity of the zero-sequence current flow area, etc.; the theoretical calculation value cannot meet the accuracy requirements for the calculation of the relay protection setting value. If the calculated 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, "220kV-500kV Power Grid Relay Protection Operation Regulations (DL / T559-94, implemented in 1995-05-01)" The regulations on relay 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 T-type line parameters by blackout measurement method requires power failure of the tested line; it is often impossible to measure the power failure of the T-type line; in addition, according to the traditional blackout method, in a wider area, the amount of equipment, work The amount is too large to bear, and the simultaneity of measurement cannot be guaranteed; therefore, it is urgently needed by the power system operation department to seek a new live measurement method for T-shaped line parameters and to develop a corresponding test system, which not only has important theoretical value, and has great economic and social benefits

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