Zero-sequence voltage trip protection method for low-voltage side of transformers

A transformer low-voltage side and transformer protection technology, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problems of increased investment in equipment costs, unsuitable protection devices, increased maintenance costs, etc., to achieve increased investment, high reliability, High safety effect

Active Publication Date: 2013-05-22
LONGTAN HYDROPOWER DEV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although these improved protection devices ensure the safe operation of the transformer to a certain extent, the improvement of equipment will undoubtedly increase the investment in equipment costs, and due to the use of new equipment, maintenance costs will also increase greatly; and most of these protection devices are not Apply to GCB

Method used

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  • Zero-sequence voltage trip protection method for low-voltage side of transformers

Examples

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Embodiment 1

[0040] A zero-sequence voltage tripping protection method adapted to the low-voltage side of the transformer. For the system where the primary neutral point grounding method on the low-voltage side of the transformer is ungrounded, two sets of voltage transformers are arranged on the low-voltage side of the transformer, and zero-sequence overvoltage tripping protection is set. Logic, protection input and protection output are used as a method for grounding protection on the low-voltage side of the transformer; where: when the voltage transformer is configured on the low-voltage side of the transformer as a double set of voltage transformer TV1 and TV2, the transformer protection device is cross-connected to the transformer low-voltage Two sets of voltage transformer star-shaped three-phase secondary windings and open delta secondary winding loops of side voltage transformers, that is, one set of transformer protection devices is connected to voltage transformer TV1 star-shaped t...

Embodiment 2

[0045] A zero-sequence voltage tripping protection method adapted to the low-voltage side of the transformer. For the system where the primary neutral point grounding method on the low-voltage side of the transformer is ungrounded, a single set of voltage transformers is arranged on the low-voltage side of the transformer, and zero-sequence overvoltage tripping protection is set. Logic, protection input and protection output are used as a method for grounding protection on the low-voltage side of the transformer; where: when the voltage transformer on the low-voltage side of the transformer is configured as a single set of voltage transformer TV, the transformer protection device is normally connected to the voltage on the low-voltage side of the transformer Transformer secondary winding and open delta winding circuit; among them, the TV primary disconnection locking discrimination formula is U2 > 0.33*U0zd and 3U0 > U0zd, where U2 is the negative sequence voltage of TV, and 3U0...

Embodiment 3

[0050] A zero-sequence voltage tripping protection method adapted to the low-voltage side of the transformer. For the system where the primary neutral point grounding method on the low-voltage side of the transformer is ungrounded, two sets of voltage transformers are arranged on the low-voltage side of the transformer, and zero-sequence overvoltage tripping protection is set. Logic, protection input and protection output are used as a method for grounding protection on the low-voltage side of the transformer; where: when the voltage transformer is configured on the low-voltage side of the transformer as a double set of voltage transformer TV1 and TV2, the transformer protection device is cross-connected to the transformer low-voltage Two sets of voltage transformer star-shaped three-phase secondary windings and open delta secondary winding loops of side voltage transformers, that is, one set of transformer protection devices is connected to voltage transformer TV1 star-shaped t...

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Abstract

The invention discloses a zero-sequence voltage trip protection method for the low-voltage side of transformers. For the fact that the primary neutral-point earthing of the low-voltage side of a transformer is an unearthed system, the method protects earthing of the low-voltage side of the transformer by configuring one or double voltage transformers on the low-voltage side of the transformer and setting zero-sequence overvoltage trip protection logic, protection input and protection output. Corresponding voltage loop breakage locking logics of the voltage transformers are selected for trip protection by means of changing control words according to configuration and wiring manners of the voltage transformers. The method effectively solves the problem of transformer low-voltage side zero-sequence voltage protection malfunction caused by primary-side and secondary-side voltage loop breakage of the voltage transformers on the low-voltage side of the transformer, and ensures accurate and reliable action of the transformer in case of single-phase earthing fault of the primary loop on the low-voltage side of the transformer.

Description

technical field [0001] The invention belongs to the technical field of power system transformer protection, in particular to a zero-sequence voltage tripping protection method in which the primary grounding mode of the low-voltage side of the transformer is an ungrounded system and has a single or double set of voltage transformers. Background technique [0002] For the case where the primary grounding method of the low-voltage side of the main transformer in a power plant is an ungrounded system and a generator outlet circuit breaker (hereinafter referred to as GCB) is installed, when the GCB is in position, a single-phase grounding fault on the low-voltage side of the main transformer is generally caused by the generator Stator ground protection to cut off isolation faults. However, when the GCB is in the sub-position, when a single-phase ground fault occurs, there will be a protection dead zone from the low-voltage outlet of the main transformer to the GCB; , Single-phas...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/04
Inventor 韦江平周永兵李琦永徐鹏陈俊陈佳胜郭自刚
Owner LONGTAN HYDROPOWER DEV
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