Thermal stability principle-based intermittent grounding protection method for small-resistance grounding system

A low-resistance grounding and grounding protection technology, applied in emergency protection circuit devices, electrical components, etc., can solve the problems of exceeding the limit of fault times, difficult to fully adapt to complex and changeable, complex fault handling problems, etc., and achieve strong anti-noise interference ability. , The protection threshold value is set objectively, and the effect of improving the reliability of power supply

Pending Publication Date: 2021-09-03
CHINA UNIV OF PETROLEUM (EAST CHINA)
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Problems solved by technology

For intermittent ground faults, since the duration of single arcing, fault arcing-reignition interval and other conditions are unknown, it is difficult to fully adapt to complex and changeable faults by the method of "the number of faults exceeding the limit within a fixed period of time". Happening
Due to the complex environment of the medium-voltage distribution network and the high incidence of

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  • Thermal stability principle-based intermittent grounding protection method for small-resistance grounding system
  • Thermal stability principle-based intermittent grounding protection method for small-resistance grounding system
  • Thermal stability principle-based intermittent grounding protection method for small-resistance grounding system

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Embodiment Construction

[0030] The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

[0031] An intermittent grounding protection method for small resistance grounding systems based on the principle of thermal stability, the processing flow is as follows figure 1 shown, including:

[0032] Step 1: Read the zero-sequence current parameters at the outlets of each line in real time. If the zero-sequence current of a certain line is greater than the protection start threshold, the protection method of the corresponding line is activated. Go to step 2. If the line zero-sequence current is less than or equal to the protection start threshold , the protection method is not started, and the heat dissipation characteristic value of each line is calculated correspondingly based on the remaining heat characteristic value of each line, and subtracted from the heat characteristic value until the heat characteristic value is zero, and then p...

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Abstract

The invention provides a thermal stability principle-based intermittent grounding protection method for a small-resistance grounding system and aims to solve the problem that the single arcing duration of an intermittent grounding fault is often smaller than a protection action time limit, and the problem that traditional grounding fault protection is difficult to process, and other problems,so as to effectively remove intermittent grounding faults. According to the technical schemes, zero-sequence current is used for constructing heating characteristic values of all outgoing lines in a fault arcing period, heat difference is used for constructing heat dissipation characteristic values after arc extinguishing, protection action is conducted after the heating characteristic values exceed the limit, and intermittent grounding faults are removed. The method provided by the invention can be used as backup protection for outgoing line protection of the existing small-resistance grounding system, and improve the operation and power supply reliability of the system.

Description

technical field [0001] The invention relates to the field of grounding fault protection of distribution networks, in particular to an intermittent grounding protection method for a small resistance grounding system. Background technique [0002] The neutral point grounding method through a small resistance has the advantages of quickly removing permanent low-resistance grounding faults, effectively weakening resonance overvoltage, and relatively simple operation and maintenance. It is one of the commonly used neutral point grounding methods for large and medium-sized urban distribution networks. After a single-phase ground fault occurs in a small-resistance grounding system, it may be affected by factors such as arcing and extinguishing characteristics of the arc period, complex external effects such as wind force and air ionization, fault line galloping, and change in dielectric strength recovery performance. Alternate arcing, Intermittent grounding phenomenon of arc exting...

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Application Information

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IPC IPC(8): H02H7/26
CPCH02H7/262H02H7/263
Inventor 薛永端任伟徐丙垠
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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