Disconnection distinguishing method and system of protection mutual inductor suitable for 3/2 wiring

A technology of external connection and transformer, which is applied in the direction of instruments, electrical connection tests, measuring devices, etc.

Active Publication Date: 2020-08-21
CHINA ELECTRIC POWER RES INST +2
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The present invention proposes a disconnection identification method and system suitable for 3 / 2 connection protection transformers to solve how to correct the disconnection of the transformer movement problem

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  • Disconnection distinguishing method and system of protection mutual inductor suitable for 3/2 wiring
  • Disconnection distinguishing method and system of protection mutual inductor suitable for 3/2 wiring
  • Disconnection distinguishing method and system of protection mutual inductor suitable for 3/2 wiring

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Embodiment approach

[0129] The substation system structure and protection configuration of the embodiment of the present invention are as figure 2 Shown. Among them, during normal operation, because the power system is a three-phase symmetrical system, the sum of the three-phase current and the zero-sequence current are zero, and the sum of the three-phase voltage is also zero; the input impedance of the port is the leakage reactance of the transformer. In the event of an external fault, the impedance of the protected object remains unchanged. In the area of ​​faults, the measured impedance of the protected object changes significantly, the measured impedance is inductive impedance, and the impedance angle is small. TA (current transformer) is disconnected, the voltage does not change but the current tends to zero, and the measured impedance tends to infinity. The TV (voltage transformer) is disconnected, the current does not change but the voltage tends to zero, and the measured impedance tends...

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Abstract

The invention discloses a disconnection distinguishing method and system of a protection mutual inductor suitable for 3 / 2 wiring, which aims to solve the problems that the abnormal alarm logic of a mutual inductor of a protection device cannot meet the field operation requirement, and a false alarm is given when both a primary system and a secondary system operate normally. However, the existing mutual inductor disconnection method has similar defects. The condition of unbalanced three-phase current distribution of each branch caused by impedance difference of each phase of two branches of theprimary system cannot be avoided. According to the scheme, the field operation requirement can be met, a false alarm is not given when the primary system and the secondary system operate normally, when an individual mutual inductors is disconnected, the protection device can correctly identify the disconnection condition and correctly act under the fault condition, the judgment capability of theprotection device for the abnormity of the mutual inductor is improved, the similar defect that the disconnection of the mutual inductor cannot be correctly judged in a current mutual inductor disconnection judgment method is avoided, and the serious consequence of protection maloperation or operation refusal caused by locking protection is avoided.

Description

Technical field [0001] The present invention relates to the technical field of power system relay protection, and more specifically, to a disconnection identification method and system suitable for 3 / 2 wiring protection transformers. Background technique [0002] With the accelerating pace of power grid construction, the grid structure is becoming more and more complex, and accidents such as alarms and misoperations of power lines and transformers' mutual inductors occur from time to time, which puts huge pressure on the safe and stable operation of power lines and transformers. Therefore, when a transformer abnormal alarm signal appears in the substation, the operation and maintenance personnel of the substation will attach great importance to the event and need to be dealt with in time. When the primary system of a substation in Fujian was operating normally, the main transformer protection device frequently issued TA (current transformer) abnormal alarms. The abnormal alarm i...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R31/66G01R35/02
CPCG01R31/66G01R35/02
Inventor 李伟艾淑云周泽昕张逸帆张晓莉杨国生刘宇刘丹王惠平夏烨施文
Owner CHINA ELECTRIC POWER RES INST
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