Single-phase high-resistance ground fault identification method for transmission lines

A technology for high-resistance ground faults and transmission lines, applied in the direction of measuring electricity, measuring electrical variables, and measuring devices, can solve problems such as load transfer, impedance distance protection malfunction or refusal, hidden dangers in power grid safety, etc., to achieve correctness and reliability The effect of action

Active Publication Date: 2016-03-30
STATE GRID CORP OF CHINA +3
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] The additional impedance generated by the transition resistance will seriously affect the action performance of the impedance distance protection
If the additional impedance generated by the transition resistance is resistive and inductive, it is easy to cause the impedance distance protection to refuse to operate when there is a fault in the protection zone of the transmission line; go beyond
[0003] High / super / extreme voltage AC transmission lines are often also heavy-duty transmission lines. Heavy-load currents will cause the impedance distance protection to malfunction or refuse to operate. The influence of heavy-load currents on the performance of impedance distance protection cannot be ignored.
Under the condition of overload transmission, the line has no faults. The measured impedance of the traditional distance protection will seriously deviate from the actual measured impedance due to the influence of the overload current, which will easily lead to the misoperation of the traditional distance protection, resulting in the expansion of the power grid blackout range, and even causing a large number of load transfers to threaten the normality of the line. operation, causing a huge security risk to the grid security

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  • Single-phase high-resistance ground fault identification method for transmission lines
  • Single-phase high-resistance ground fault identification method for transmission lines
  • Single-phase high-resistance ground fault identification method for transmission lines

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Embodiment Construction

[0014] The technical solution of the present invention will be further described in detail according to the accompanying drawings.

[0015] figure 1 It is a schematic diagram of the line transmission system applying the present invention. figure 1 The middle CT is a current transformer. The protection device measures the current instantaneous value at each sampling moment where the current transformer of the transmission line is installed.

[0016] The protection device selects the sampled values ​​of one-cycle fault phase current i(t), i(t+Δt),..., i(t+(N-1)Δt), and calculates the sampled values ​​of the first half-cycle fault phase current integral value of , to calculate the integral value of the second half-cycle fault phase current sampling value ; Among them, i(t), i(t+Δt), ..., i(t+(N-1)Δt) are t, t+Δt, ..., t+(N -1) The sampling value of the fault phase current at the sampling time of Δt; i(t+xΔt) is the sampling value of the fault phase current at the sampling ...

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Abstract

The invention discloses a single-phase high-impedance grounding fault recognition method of a power transmission line. The method includes measuring instantaneous values of current of mounting positions of current transformers of the power transmission line at sampling instants, selecting one-cycle wave fault-phase current sampled values, computing an integral value of front half-cycle wave fault-phase current sampled values and an integral value of latter half-cycle wave fault-phase current sampled values, further utilizing the integral value of the front half-cycle wave fault-phase current sampled values and the integral value of the latter half-cycle fault-phase current sampled values to form relay protection criteria, and accurately discriminating single-phase high-impedance grounding faults of the power transmission line. The method has the advantages that single-phase high-impedance grounding fault relay protection of the power transmission line is achieved by the aid of single-terminal current magnitude, action performance is unaffected by transition resistance, fault location and load current, and action can be accurate and reliable during single-phase high-impedance grounding faults of the power transmission line.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a single-phase high-resistance grounding fault identification method of a power transmission line. Background technique [0002] The additional impedance generated by the transition resistance will seriously affect the action performance of the impedance distance protection. If the additional impedance generated by the transition resistance is resistive and inductive, it is easy to cause the impedance distance protection to refuse to operate when there is a fault in the protection zone of the transmission line; beyond. [0003] High / super / extreme voltage AC transmission lines are often also heavy-duty transmission lines. Heavy-load currents will cause impedance distance protection to malfunction or refuse to operate. The impact of heavy-load current on the performance of impedance distance protection cannot be ignored. Under the condition of overl...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R31/02
Inventor 林富洪曾惠敏
Owner STATE GRID CORP OF CHINA
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