Views:191 Author:Site Editor Publish Time: 2020-09-24 Origin:Site
General line faults mainly include single-phase grounding, phase to phase short circuit, and grounding phase to phase short circuit.
The causes of high resistance fault can be divided into two types: one is that the distribution line breaks during operation, so it contacts with high impedance; the second case is that the normal distribution line breaks and touches the objects around the line. When the high resistance fault occurs, the current level is obviously lower than that caused by a short circuit, which has a certain impact on the normal operation of the accurate cable fault indicator. Due to the low detection rate of automated cable fault indicators for the problem, this kind of fault cannot be adjusted in time, which leads to a more serious fault in the distribution system.
The single-phase to ground fault is the most frequent and difficult power fault in distribution lines. Because it is not enough to cause tripping, it has no obvious identification mark. The inspection of this fault mainly analyzes the transient signal in the circuit system through the reliable cable fault indicator or digital fault current indicator, because of the transient signal of the circuit system stores a lot of information about the line fault. Another characteristic of the transient process is that it can avoid the influence of grounding mode, so strengthening the analysis of the transient process is helpful to judge the fault.
Intermittent fault mainly refers to the phenomenon of intermittent discharge in the operation process of the distribution line, which will produce arc light when discharging. When the intermittent fault of the distribution line occurs, the line maintenance personnel should timely use the advanced cable fault indicator to check the cause. If the fault cannot be found in time, the maintenance personnel of the power enterprise cannot do the maintenance work of the line for the first time, which will lead to a chain reaction of the line.
The passive location method mainly uses section search and impedance method to find the fault of the distribution line in a power system. Through the automated fault current indicator in the distribution network, the passive location of each section of the distribution line can clearly find out the section where the distribution fault occurs. The advanced cable fault indicator monitoring system of the distribution network can analyze and study the section where the line fault occurs through the operation data, so as to reduce the scope of the fault point, which can greatly shorten the time needed to find the fault.
The neutral point pulse width injection method has no obvious shortcomings. Due to the limiting factors such as environment, it has high safety and accuracy, which can improve the efficiency of fault detection.
The detection and location method is mainly to install accurate cable fault passage indicators in each branch point to strengthen the detection of operation status of each section, which can effectively monitor and record various parameters in the operation of the distribution line. When the monitoring data displayed in the reliable cable fault indicator monitoring system is abnormal, professionals can calculate the specific location of the fault according to the data. Although this detection method is more efficient, it costs more to install reliable fault current indicators for all distribution lines in the area.