Automatic integrated processing method for single-phase earth fault

Abstract

The invention provides an automatic integrated processing method for a single-phase earth fault, and belongs to the field of emergency protective devices. The automatic integrated processing method for the single-phase earth fault comprises the steps: S1, a controllable electric reactor and a small resistor are arranged on a earth connection return circuit of a converting station, the controllable electric reactor outputs a compensating current when a power distribution network has an earth fault; S2, lasting time of the single-phase earth fault is measured and recorded; S3, the single-phase earth fault is confirmed to be instant grounding when the lasting time of the single-phase earth fault is shorter than preset time; S4, the single-phase earth fault is confirmed to be permanent grounding when the lasting time of the single-phase earth fault is longer than the preset time; and S5, a first treatment measure and a second treatment measure are conducted to the instant grounding and the permanent grounding respectively. Therefore, the permanent earth fault is isolated quickly and accurately, expansion of an accident caused by the fact that overvoltage of power frequency of a system exists for long time is avoided, instant earth fault is compensated accurately and disappears automatically, tripping operation is not needed, and the safety and reliability of the system are improved. Further, the automatic one-in-all processing method for the single-phase earth fault can be widely used in the field of converting station system protection.

Description

technical field [0001] The invention belongs to the field of substation emergency protection devices, and in particular relates to a processing method for single-phase grounding faults. Background technique [0002] The selection of the neutral point grounding method of the distribution network is closely related to the safety, operation reliability and economy of the power system, and it is a problem that must be paid attention to in the construction of urban and rural power grids. [0003] The choice of grounding method should not only consider the structure and equipment of the distribution network at that time, but also be restricted by the technical level of the grounding equipment. [0004] At present, the neutral point grounding mode of the distribution network has two modes: arc suppressing coil grounding and small resistance grounding. Both modes have their own advantages and disadvantages. Among them, the arc suppressing coil grounding mode can reduce the grounding...

AI Technical Summary

Problems solved by technology

[0004] At present, the neutral point grounding mode of the distribution network has two modes: arc suppressing coil grounding and small resistance grounding. Both modes have their own advantages and disadvantages. Among them, the arc suppressing coil grounding mode can reduce the grounding current and reduce the occurrence of arc overvoltage. Probability, but the disadvantage is that the grounding time is too long, the power frequency overvoltage of the system exists for a long time, and it is difficult to isolate the faulty line; the small resistance grounding method can accurately jump the faulty line by generating a large current signal, but it is not suitable for instantaneous grounding faults and permanent faults. Ground faults are always tripped, and the trip rate is high, which reduces the reliability of the system power supply

[0005] The grounding method of the arc suppression coil can automatically eliminate the instantaneous single-phase ground fault, and has the advantages of reducing the number of trips and the ground fault current. However, since the non-transient single-phase ground fault cannot be eliminated, the entire power distribution system must withstand a long time (2 Hours) power frequency overvoltage (line voltage), so the insulation level of the equipment is high, which is unfavorable for power distribution system equipment (especially for some imported equipment, such as cables); at the same time, the long-term single-phase ground fault The presence is also not conducive to equipment and personal safety

Moreover, the fault line selection in the traditional arc suppression coil grounding system has always been a technical problem

Over the years, the accuracy of the actual line selection of the distribution network has been low. It is time-consuming and labor-intensive to find and eliminate grounding faults by using manual routing.

[0006] The small resistance grounding method can avoid the problem of long-term power frequency overvoltage in the power distribution system, and has relatively low requirements for equipment insulation. The disadvantage is that any single-phase ground fault in the system will trip, especially for overhead and cable mixed lines. rate is too high, reducing the reliability of power supply

[0007] Therefore, these two grounding methods have their own advantages and disadvantages, and can only be applied to certain conditions.

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