Distribution network fault line selection method based on zero-mode current multi-order difference transformation

A zero-mode current, fault line selection technology, applied in the fault location and other directions, can solve the problems of damaged circuit breakers, line power outages, and extended power outage time, and achieve the effect of accurate line selection results, high reliability, and small effectiveness.

CN104133158AInactive Publication Date: 2014-11-05KUNMING UNIV OF SCI & TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2014-11-05
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to a distribution network fault line selection method based on zero-mode current multi-order difference transformation and belongs to the technical field of power system relay protection. When feeder lines in a distribution network are in a single-phase earth fault, zero-mode current traveling wave data, recorded into a short time window, of the feeder lines are extracted for multi-order difference transformation; if a first nonzero value achieved after transformation is carried out is greater than zero, it is judged that the feeder lines are in the single-phase earth fault; if the first nonzero value is smaller than zero, it is judged that the feeder lines are not in the single-phase earth fault. By the utilization of the zero-mode current data, in the short time window, of the feeder lines after the fault occurs, at the moment, an arc suppression coil does not compensate for a system, so that the method avoids influence on the compensation effect of the arc suppression coil, and fault feeder lines can be judged out accurately and reliably.
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Description

Technical field

[0001] The invention relates to a distribution network fault line selection method based on zero-mode current multi-order differential transformation, and belongs to the technical field of power system relay protection. Background technique

[0002] The distribution network directly faces users and provides electricity services for them, so it has the widest coverage. There are various types of faults in the distribution network, but according to statistics, single-phase ground faults account for about 80% of the distribution network faults. The resonant grounding system of the distribution network is the neutral point grounded system through the arc suppression coil, which is a low-current grounding system. Most of the distribution networks in my country adopt this operation mode. A single-phase grounding fault in a small current grounding system will affect the non-faulty phase-to-ground voltage and cause it to increase, which will damage the insulation of powe...

Examples

Embodiment 1

[0024] Example 1: Such as figure 1 Shown is a distribution network with a 35kV neutral point grounded by an arc suppression coil composed of 6 feeder lines. The G in the grid is an infinite power supply; T is the main transformer with a transformation ratio of 110kV / 35kV and the connection group is YN / d11;

[0025] T Z It is a special Z-shaped transformer for grounding of the compensation grid; L is the arc suppression coil, and R is the damping resistance of the arc suppression coil. The line uses overhead lines, overhead lines-cable hybrid lines and cable lines. The number of the six feeders is L 1 ,L 2 ,L 3 …L 6 , Where L 1 It is an overhead line with a length of 15km; L 2 It is a cable with a length of 6km; L 3 It is an overhead line with a length of 18km; L 4 It is a cable mixed line, the cable length is 5km, and the overhead line length is 12km; L 5 It is an overhead line with a length of 30km; L 6 It is a cable with a length of 8km. Set feeder L 1 The AG metallic fault oc...