Views:205 Author:Site Editor Publish Time: 2021-05-27 Origin:Site
The short circuit and earth fault indicator provides a powerful tool for fault finding of the power system, and is popular with the majority of line maintenance personnel. At present, with the development of technology, the technical content of the short circuit and earth fault indicator is continuously improved, and there are many varieties. According to different points of the transmission and distribution circuit, the short circuit and earth fault indicator is also divided into the following categories.
The short circuit and earth fault indicator is designed to comprehensively consider the characteristics of the transmission line when grounding and short-circuiting. On the one hand, according to the principle of grounding detection, it can detect the instantaneous transient capacitor discharge current, and when the line voltage drop is detected, the line is considered to be grounded , otherwise the line is not grounded. On the other hand, according to the electrical short circuit phenomenon, the positive mutation of the current and the power failure of the protection action at the moment of the power line short circuit are the basis for the action.
The panel type fault indicator is used in high-voltage cables and multiple cable power supply systems. It has the functions of cable short circuit current alarm indication, grounding alarm indication, automatic reset system, manual reset and test.
The high voltage fault indicator is a device used to detect grounding or power short circuit fault points for 110KV and above lines. It is divided into single power supply line and dual power supply network indicator, single power supply line fault indicator, the design principle is to use the positive current mutation and line power failure to detect the fault point when the line fails, and add a fast detection circuit. For dual-power networked power supply lines, the design principle is based on the current mutation and power direction judgment when the line fails. When the short circuit moment, the current mutation is greater than a certain value and the same as the set power direction, and the line will soon be affected by the failure. If there is a power failure, the line is considered to be faulty.
A signal source fault detection system is used to indicate the grounding or short-circuit fault point of the overhead power line. The detection principle is that when a ground fault occurs on the line, the signal source receives the signal from the busbar PT of the substation, and after judgment, it sends an instruction, which is fed back to the fault indicator hung on the phase line through the signal source. All the indicators between the substation and the substation are displayed on the flip card, and the indicators after the ground fault point do not work, so it is easy to judge the ground fault point.
The power line remote monitoring system can monitor the various operating status of the line in real time and quickly confirm the changes and locations of the operating status of the monitored line. When the operating status of the line changes, such as power transmission, power failure, phase loss, grounding, short circuit, overcurrent, etc., the line signal collector detects the changed signal, and the changed signals are transmitted out by wireless devices in a coded manner. As the receiving terminal, after processing by the computer, it informs the staff on duty by means of sound and light alarm, screen display, etc. The operating status of the power line fault indicator changes and confirm the location of the change.