One-point grounding detection device and detection method for neutral line of secondary coil of voltage transformer

Abstract

The invention discloses a detection device and a detection method for one-point grounding of the neutral line of the secondary coil of a voltage transformer. Between; adjust the resistance value of the sliding wire rheostat to obtain the corresponding current reading in the ammeter; connect the voltmeter between the neutral line of the secondary coil of the voltage transformer and the equipotential ground network; use the voltmeter to detect the sliding wire The variation of the resistance value of the varistor; the discharge gap and the knife switch are respectively connected between the neutral line of the secondary coil of the voltage transformer and the equipotential ground network, the discharge gap is used for overvoltage protection, and the knife switch is used to control the connection in the test On and off of the location. The invention is suitable for detecting the reliability of the grounding of the secondary circuit of the voltage transformer during operation, improves the correct rate of relay protection actions in the substation, and ensures safety.

Description

technical field [0001] The invention relates to a device and a detection method for detecting the reliability of one-point grounding of a neutral line (N600) of a voltage transformer secondary coil during operation. Background technique [0002] At present, the grounding reliability of the neutral line N600 of the secondary coil of the substation voltage transformer in operation cannot be detected, and whether it is grounded or not during normal operation and whether it is multi-point grounded cannot be detected. When a ground fault occurs in the system, the ground grid of the substation will flow zero-sequence current. If there are multiple points grounded, a voltage difference will be generated between the two ground points, resulting in incorrect voltage values ​​measured by the protection device and waveform distortion, resulting in impedance components and incorrect action of the directional element. If the grounding point is lost, the distributed capacitance between t...

AI Technical Summary

Problems solved by technology

[0002] At present, the reliability of the grounding of the neutral line N600 of the secondary coil of the substation voltage transformer in operation cannot be detected, and whether it is grounded or not during normal operation and whether it is multi-point grounded cannot be detected

When a ground fault occurs in the system, zero-sequence current will flow through the substation ground network. If there are multiple ground points, a voltage difference will be generated between the two ground points, resulting in incorrect voltage values ​​measured by the protection device and waveform distortion, resulting in impedance components and incorrect action of the directional element

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