Views:190 Author:Site Editor Publish Time: 2021-01-19 Origin:Site
The fault indicator is composed of a sensor and a display. The line fault indicator sensor is responsible for detecting the current passing through the cable, and the display is responsible for judging the current information from the sensor and making fault indication actions. After the power line fault indicator is installed on the line, when the system fails to be delivered, the fault current appears on the line from the fault point to the feed point, resulting in all fault indications operating on the line from the fault point to the feed point, the indicator light will flash. Start from the feed point, and keep searching along the line where the fault indicator is shining. The last shining point is the fault point. Popularizing the use of fault indicators helps to find fault points in a shorter time, and is an effective way to improve the operation level of the distribution network and the efficiency of accident handling.
1). Grounding detection principle
Sampling the first half-wave of the capacitor current at the moment of grounding and the first half-wave of the voltage at the moment of grounding, compare their phases, when the capacitor current at the moment of sampling grounding suddenly changes and is greater than a certain value, and is in phase with the first half-wave of the voltage at the moment of grounding, and the wire is a short circuit to earth. If the voltage drops, it is judged that the line is grounded, otherwise, the line is not grounded.
2). Principle of short circuit detection
According to the electrical short circuit phenomenon; at the moment of short-circuit, the positive current mutation and the protection action power outage are used as the action basis.
l). Fault indication: In normal operation, the window is displayed in white; when a power short circuit fault occurs, the window is displayed in red.
2). Automatic reset: After the line is restored to power, the automated cable fault indicator will automatically reset. The reset time can be selected by the customer according to the line environment, line inspection length, department requirements, etc.
3). Live loading and unloading: Live loading and unloading is extremely simple and does not affect line operation.
4). Provides technical means for finding hidden fault points.
5). Quickly indicate fault lines and fault points to shorten troubleshooting time.
6). Accurately indicate instantaneous faults, which is helpful to eliminate power supply hazards.
7). Avoid the influence of traditional multiple times of opening and patrolling the power equipment.
Installed in the middle section of the long line and at the entrance of the branch: it can indicate the faulty section of the line and the faulty branch.
Installed at the exit of the substation: it can be determined that the short circuit and earth fault is inside or outside the station.
Installed at the user's distribution transformer high-voltage incoming line( high voltage fault indicator): it can be determined whether the fault is caused by the user.
Installed at the connection of cable and overhead power lines: It can distinguish whether the fault is in the cable section.