Current voltage transformer secondary neutral grounding current acquisition device

Abstract

A current voltage transformer secondary neutral grounding current acquisition device provided by the present invention comprises a first branch, a second branch and a voltage source, and the first branch comprises a current inductor, a first relay and a second relay. The current inductor is used to sense a grounding line current and generate a current signal, the first relay is used to close a first normally open contact when the sensed current is greater than a preset threshold value, and the first branch is conducted with the voltage source. The second relay is used to close a second normally open contact when the first relay is closed, and the second branch comprises a third relay and an alarm part. The third relay is used to close a third normally open contact when the second relay is closed, the second branch is conducted with the voltage source, and the alarm part is used to output an alarm signal when the second branch is conducted with the voltage source. By implementing the current voltage transformer secondary neutral grounding current acquisition device of the present invention, the current of a switch place can be acquired timely, a current voltage transformer secondary grounding fault can be determined effectively, the potential safety hazards can be noticed and eliminated timely, and the safe and stable operation of a power grid is guaranteed.

Description

technical field [0001] The invention relates to the technical field of secondary neutral grounding of current and voltage transformers, in particular to a current acquisition device for secondary neutral grounding of current and voltage transformers. Background technique [0002] At present, there are often more or less problems in the secondary neutral line of current and voltage transformers, such as multi-point grounding, poor contact, wrong wiring, etc., which will lead to abnormal voltage of the secondary branch circuit, cause incorrect action of protection, and cause serious damage. harm. [0003] Such as figure 1 As shown, when the current and voltage transformers are grounded at the switch site (such as point N) and the control room (such as the grounded neutral line N600) respectively, if a ground fault occurs in the system, the ground grid of the substation will flow a large fault current. A potential difference ΔU is generated between the N point and the O point...

AI Technical Summary

Problems solved by technology

[0002] At present, there are often more or less problems in the secondary neutral line of current and voltage transformers, such as multi-point grounding, poor contact, wrong wiring, etc., which will lead to abnormal voltage of the secondary branch circuit, cause incorrect action of protection, and cause serious damage. harm

[0003] like figure 1 As shown, when the current and voltage transformers are grounded at the switch site (such as point N) and the control room (such as the grounded neutral line N600) respectively, if a ground fault occurs in the system, the ground grid of the substation will flow a large fault current. A potential difference ΔU is generated between the N point and the O point, so that the N point, the O point and the grounded neutral line N600 form a branch circuit, thereby causing a shift in the phase of the neutral point voltage, affecting the amplitude and phase of the phase voltage and the zero-sequence voltage , and may even lead to serious consequences such as distance protection, zero-sequence direction protection refusal or misoperation

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