Zero sequence voltage compensation element locking method for double-circuit same-tower line

Abstract

The invention discloses a zero sequence voltage compensation element locking method for a double-circuit same-tower line. The zero sequence voltage compensation element locking method comprises the following steps: firstly, after the protection device of the line is powered on, acquiring the zero sequence current, negative sequence current and zero sequence voltage vector and amplitude of the protected line, judging whether the zero sequence current amplitude meets a threshold value or not, and if so, starting zero sequence direction protection; and secondly, judging whether the zero sequence voltage amplitude meets a threshold value or not, if the zero sequence voltage amplitude is lower than the threshold value, comparing the negative sequence current amplitude with the zero sequence current amplitude, when the ratio of the negative sequence current amplitude to the zero sequence current amplitude is greater than 0.8, starting a zero sequence voltage compensation element, performing zero sequence direction calculation by using a compensated zero sequence voltage vector, or else performing zero sequence direction calculation by using the locked zero sequence voltage compensation element directly. By adopting the zero sequence voltage compensation element locking method, a long-distance double-end co-bus same-tower double-circuit line can be ensured, and in case of an asymmetric longitudinal fault of one circuit line, the zero sequence direction protection of the other circuit line has no mal-operation but can act reliably when a grounding fault happens in an area.

Description

Technical field: [0001] The invention relates to the technical field of longitudinal zero-sequence direction protection of double-circuit lines on the same tower, and in particular to a method for blocking zero-sequence voltage compensation elements of long-distance double-circuit lines on the same tower. Background technique: [0002] In order to solve the problem that the zero-sequence directional element fails due to low zero-sequence voltage when the long-line end fault or high-resistance grounding fault occurs, the method of zero-sequence voltage compensation is often used for the zero-sequence directional element. Zero-sequence voltage compensation is established based on the characteristics of the zero-sequence fault component network when a ground fault occurs. When a forward ground fault occurs, the zero-sequence voltage after compensation increases significantly, and the action of the zero-sequence directional element is more reliable. When a fault occurs, the zero...

AI Technical Summary

Problems solved by technology

[0004] For the problem that the zero-sequence directional element with zero-sequence voltage compensation of the long-distance double-terminal common bus line and the double-circuit line on the same tower may misjudge when an asymmetric longitudinal fault occurs on one circuit line, the present invention provides a method for The zero-sequence voltage compensation element blocking method of the double-circuit line on the same tower can only use the electrical information of the single-circuit line to distinguish between the high-resistance ground fault at the end of the line and the asymmetrical longitudinal fault of the adjacent line, and avoid the zero-sequence voltage compensation element in the phase Misjudgment of zero-sequence directional elements due to false start when asymmetrical longitudinal faults occur on adjacent lines

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