Views:196 Author:Site Editor Publish Time: 2021-05-13 Origin:Site
Due to long lines, low load, weak fault current and unstable fault characteristics in rural remote areas, it is difficult to locate the line fault point. The traditional fault location methods such as traveling wave ranging method, impedance method and signal injection method have not been widely used due to their limitations. In recent years, due to the rapid development of electronics and communication technology, some new types of fault indicators have been widely used. Aiming at the characteristics of long distribution network lines and low load in remote areas of rural power grids, this article will put forward the problems and suggestions that should be paid attention to when selecting overhead fault indicators in terms of fault detection principle, communication mode selection, working environment requirements and so on.
Distribution networks in remote rural areas are generally distributed in rural areas and mountainous areas, with long lines and easy damage by external forces. To accurately find out and locate the fault type when a line fails, it is necessary to consider the grounding method of the neutral point of the line, because the grounding method of the neutral point affects the characteristic appearance after the fault occurs. Most of the medium and high voltage power transmission and distribution networks below 35 kV in China adopt the grounding method of neutral point ungrounded or arc suppression coil, that is, low current grounding method. When a single-phase grounding fault occurs, it is difficult to locate the fault point in remote rural areas due to long lines, low load, weak fault current, and unstable fault characteristics. Traditional fault location methods such as traveling wave ranging method, impedance method and signal injection method have not been popularized and applied due to high cost, large amount of calculation and complex application.
The power fault indicator is an intelligent device installed on the power line to indicate the fault current path. It can intelligently judge, warn, display the fault in real time and automatically reset. The setting mode of the early line fault indicator is fixed. There is only one specific current value for selection. Due to the influence of current fluctuations, magnetizing inrush current, higher harmonics, distributed capacitance and electromagnetic interference, the general action accuracy is not high. In recent years, due to the rapid development of electronics, sensing and communication technologies, some new power line fault indicators have been widely used. The new type of cable fault indicators is generally based on digital electronic components, and its action logic and setting value can be set and adjusted according to factors such as line length, load level, protection mode, etc., which further enhances the practicality of the fault indicator.
In the face of numerous product providers, fault current indicators suitable for the actual situation in the region should be selected. Here we will discuss the factors that need to be considered when selecting fault path indicators from the practical perspective of rural power grids in remote areas.
1) Principles and methods of fault detection.
2) Communication method.
3) Working environment temperature.
4) Product life.
5) Communication interface.
At present, the short circuit fault indicators of different manufacturers have their own technical advantages and limitations. Combining the actual situation of the rural distribution network, we can better choose the products suitable for the region. At the same time, it is also recommended that manufacturers apply new technologies such as artificial intelligence, increase research and development efforts, and develop accurate cable fault indicators with simple applications and high accuracy to better serve power production.