CN110687389A

CN110687389A - Method for measuring key parameters of transfer grounding device and judging arc extinction of fault point

Info

Publication number: CN110687389A
Application number: CN201810728338.7A
Authority: CN
Inventors: 李政洋; 李景禄
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-07-05
Filing date: 2018-07-05
Publication date: 2020-01-14
Anticipated expiration: 2038-07-05
Also published as: CN110687389B

Abstract

The invention relates to a method for measuring key parameters of a transfer grounding device and judging arc extinction of a fault point, which measures key parameters of a power grid, a feeder line capacitance current and the like, timely knows the state of the fault point by tracking the parameter change of a fault line in the process of processing the grounding fault by the device, judges whether the fault is recovered or not, and restores the device to reduce the probability of occurrence of a short circuit of a different-name phase.

Description

Method for measuring key parameters of transfer grounding device and judging arc extinction of fault point

Technical Field

The invention relates to the field of one-ground fault processing, which is mainly used for measuring key parameters of a transfer grounding device and judging a fault point arc extinction method.

Background

The single-phase earth fault processing by the fault phase transfer earthing device is to switch on a fault phase earth switch after a fault phase is selected, transfer fault current, clamp fault potential and process the single-phase earth fault of the power distribution network. The single-phase earth fault of the power grid has a permanent earth fault and a transient fault caused by insulator discharge. The transition resistance from the fault point to the ground is classified, namely, a low-resistance fault and a high-resistance fault exist. When the single-phase earth fault is processed by the fault phase-transfer earthing device, no matter whether the fault is a low-resistance earth fault or a high-resistance earth fault, all the fault phase transfer switches of the fault phase transfer grounding device are converted into metallic grounding after being switched on to the ground, if a low-impedance grounding fault of a different-name phase occurs in the process, the single-phase grounding is converted into an inter-phase short circuit, particularly, when dealing with high-resistance earth fault, because the time for escaping from the power supply of the electrocuted person is considered, the time of the earth switch is required to be switched on to earth, the probability of the occurrence of the different-name phase earth is higher for the overhead line, and because the high-resistance grounding is changed into metallic grounding after the grounding transfer switch is switched on to the ground, the short-circuit current is large after the unlike phase grounding fault occurs, the impact on the power grid is large, and the transformer can be seriously impacted by short circuit because the short circuit point is at the transformer substation. Not only the power supply reliability of the power grid is reduced, but also the safety of the power grid is influenced, so that whether the arc of a fault point is extinguished and whether the fault is recovered or not must be judged in time in the period, and if the fault is recovered, the device should be restored in time to reduce the probability of occurrence of the short circuit of different-name phase-to-phase ground.

Disclosure of Invention

According to the invention, by measuring key parameters such as power grid and feeder line capacitance current, the state of a fault point is known in time by tracking the parameter change of a fault line in the process of processing the ground fault by the device, whether the fault is recovered or not is judged, and the probability of occurrence of a short circuit of a different-name phase ground is reduced.

After the grounding device is put into operation or the operation mode of the power grid is changed, any one of the relative ground switches of the device is switched on, the grounding current at the position of the measurement transfer grounding switch is the system capacitance current, the zero sequence current of each feedback line is the capacitance current of the feedback line, I_c10、I_c20、…I_cj0…I_cn0(ii) a After the single-phase grounding fault occurs and before the grounding transfer switch is switched to the ground, selecting a fault line with the single-phase grounding through a certain grounding line selection method; after a transfer switch of a transfer grounding device is switched on to the ground, once the zero sequence current value of a fault feeder line is detected to be equal to the self capacitance current value of the feeder line, I_j0=I_cj0And if the fault point is a discharge fault, the single-phase grounding switch of the fault phase transfer grounding device can be disconnected, and whether the fault is recovered or not is judged according to fault state parameters such as neutral point displacement voltage, fault feeder line current and the like.

The system capacitance current measured by the method is the capacitance current which is arranged on the same bus system with the transfer grounding device; the measured capacitance current of each feeder line is the capacitance current of the feeder line in the operation mode, I_c10、I_c20、…I_cj0…I_cn0。

Zero sequence electricity of fault feeder lineThe current value is equal to the self capacitance current value of the feeder line, I_j0=I_cj0The fault point arc quenching judgment method indicates that the grounding current of the fault point is completely transferred by the grounding transfer switch of the fault transfer grounding device, the grounding current of the fault point is zero, but the insulation of the fault point is not shown to be recovered normally at the moment, so that after the fault phase transfer grounding switch is disconnected to judge whether the fault is recovered, final judgment is carried out according to fault state parameters such as neutral point displacement voltage, fault feeder line current and the like.

The invention has the following advantages:

1. the method measures key parameters such as system capacitance current, each feeder line capacitance current and the like, and timely knows the state of a fault point by tracking the parameter change of a fault line in the process of processing the grounding fault by the device to judge whether the fault is recovered to reset the device, thereby reducing the probability of occurrence of the short circuit of the different-name phase grounding. .

2. The method is simple and accurate for measuring the capacitance current of each feeder line of the capacitance current of the power grid.

3. The method is verified by a large number of tests, and is simple and easy to implement.

Detailed Description

And switching on any one of the relative ground switches of the fault transfer grounding device after the fault transfer grounding device is put into operation or the operation mode of the power grid is changed, and measuring the grounding current at the position of the transfer grounding switch to obtain the system capacitance current. Measuring and storing the zero sequence current of each feeder line through the zero sequence current transformer of each feeder line, namely the capacitance current, I, of the feeder line_c10、I_c20、…I_cj0…I_cn0(ii) a After the single-phase grounding fault occurs and before the grounding transfer switch is switched on to the ground, selecting a fault line with the single-phase grounding through a certain grounding line selection method; after a transfer switch of a transfer grounding device is switched on to the ground, once the zero sequence current value of a fault feeder line is detected to be equal to the self capacitance current value of the feeder line, I_j0=I_cj0The fault point grounding arc is extinguished, the fault is a discharge fault, and the single-phase grounding switch of the fault phase transfer grounding device can be disconnected at the moment, so that the fault point grounding arc is extinguished according to the neutral point displacement voltage, the fault feeder line current and the likeAnd judging whether the fault is recovered or not by using the fault state parameter.

Zero sequence current value of fault feeder line is equal to self capacitance current value of the feeder line, I_j0=I_cj0The fault point arc quenching judgment method indicates that the grounding current of the fault point is completely transferred by the grounding transfer switch of the fault transfer grounding device, the grounding current of the fault point is zero, but the insulation of the fault point is not shown to be recovered normally at the moment, so that after the fault phase transfer grounding switch is disconnected to judge whether the fault is recovered, final judgment is carried out according to fault state parameters such as neutral point displacement voltage, fault feeder line current and the like.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that several modifications and adaptations to those skilled in the art without departing from the principles of the present invention should also be considered within the scope of the present invention.

Claims

1. The utility model provides a be used for shifting earthing device key parameter measurement and fault point arc-quenching judgement method which characterized in that: after the fault transfer grounding device is put into operation or the operation mode of a power grid is changed, any one of the relative ground switches of the device is switched on, the grounding current measured at the position of the transfer grounding switch is the system capacitance current, the zero sequence current of each feeder line is the capacitance current of the feeder line, Ic₁₀、Ic₂₀、…Ic_j0…Ic_n0(ii) a After the single-phase grounding fault occurs and before the grounding transfer switch is switched on to the ground, selecting a fault line with the single-phase grounding through a certain grounding line selection method; after a transfer switch of a transfer grounding device is switched on to the ground, once the zero sequence current value of a fault feeder line is detected to be equal to the self capacitance current value of the feeder line, I_j0=Ic_j0And if the fault point is a discharge fault, the single-phase grounding switch of the fault phase transfer grounding device can be disconnected, and whether the fault is recovered or not is judged according to fault state parameters such as neutral point displacement voltage, fault feeder line current and the like.

2. The method for measuring key parameters of a transferred grounding device and judging arc quenching of a fault point according to claim 1, wherein: the system capacitance current measured by the method is the capacitance current which is arranged on the same bus system with the transfer grounding device; the measured capacitance current of each feeder line is the capacitance current, Ic, of the feeder line in the operating mode₁₀、Ic₂₀、…Ic_j0…Ic_n0。

3. The method for measuring key parameters of a transferred grounding device and judging arc quenching of a fault point according to claim 1, wherein: zero sequence current value of fault feeder line is equal to self capacitance current value of the feeder line, I_j0=Ic_j0The fault point arc quenching judgment method indicates that the grounding current of the fault point is completely transferred by the grounding transfer switch of the fault transfer grounding device, the grounding current of the fault point is zero, but the insulation of the fault point is not shown to be recovered normally at the moment, so that after the fault phase transfer grounding switch is disconnected to judge whether the fault is recovered, final judgment is carried out according to fault state parameters such as neutral point displacement voltage, fault feeder line current and the like.