Principle and Installation Application of 10kv Fault Indicator

The cable fault indicator is an important equipment and instrument that can intelligently judge, detect and locate grid operation faults according to changes in current and voltage in the grid lines. It is usually installed in the power transmission network and is mainly used to monitor and detect possible short-circuit and single-phase grounding faults in the line. When a short-circuit occurs in the power network, the current value in the line changes suddenly, and the fault current When passing through the indicator, it will trigger the flop or flash action of the indicator, and the non-fault current will not affect its normal display. At the same time, most of the fault indicators are equipped with an automatic delay reset function. When the fault is eliminated and the power transmission is resumed, the fault indicator will automatically reset to prepare for the next detection, which makes the daily detection and maintenance of the power grid more convenient and faster.

Currently, phase-to-phase short-circuit and single-phase-to-ground faults are most likely to occur in power network transmission, so the design of the fault indicator is also set according to these two types of faults. Phase-to-phase short circuit refers to the mutual contact between two or three phases of the transmission line, resulting in the occurrence of line short circuit faults. When a short circuit occurs between phases, the instantaneous current in the line increases suddenly, and a sudden current jump is formed. The current mutation value is set inside the fault indicator. If the current change exceeds the set value, the indicator will display Corresponding fault signal. For the judgment basis and principle of single-phase grounding, the zero-sequence current amplitude method is most used at present, that is, the temporary current, voltage and other data values are collected in the distribution network where the neutral point is not directly grounded, and then the steady-state zero-sequence method is used. The fundamental wave or higher harmonic of current and voltage calculates and analyzes the collected data, so that the current and voltage values in the line are judged. If it is a fault current, the display will turn over or light up, otherwise the indicator will not change.

The active two-in-one fault indicator is widely used in the 10kV high-voltage network. It can not only indicate phase-to-phase short-circuit faults, but also detect single-phase ground faults. Its installation and application are mainly as follows:

1. Host installation. The main unit of the active two-in-one fault indicator is 95*50*85mm in size, and the opening specification of the cabinet storing the main unit is 90(length)*45(width)mm. The installation of the host is relatively simple, you only need to press the four shrapnels on the top of the host and put it into the cabinet to complete the installation of the host.

2. The installation of the grounding sensor. The grounding sensor is designed to sense single-phase grounding short-circuit current, so the device must be installed on each phase-separated three-core cable, so that the sensor can receive and sense the grounding current of each phase. When installing the grounding sensor, first unscrew the screw with a screwdriver, open the metal snap ring, and then put the metal snap ring on
On each three-core cable, tighten and fix it with a screwdriver at last, and at the same time tighten the lock buckle to firmly fix the buckle on the cable, so as to prevent the sensor from falling off.

3. Install the short circuit sensor. The short-circuit sensor is to monitor whether there is a short-circuit current between the phases of the cable. Therefore, the short-circuit sensor is often installed on the branch of the single-phase cable. The installation method and steps are similar to the ground sensor. First, unscrew the screw with a screwdriver to open the metal snap ring. Then put the snap ring on the cable branch and again
Tighten the screws, and if there is still looseness, secure by adjusting the screw on top of the sensor.

4. Connection of fiber optic cables. After the host and sensor of the fault indicator are installed, the installer connects the sensor with the host with an optical fiber cable, so that the current information received by the sensor on the cable can be transmitted to the host through the optical fiber, so that according to the current size, the host judges whether to flop or flash. When installing, insert the fiber optic cable into the fiber end of the host, and then tighten the fiber cap, so that the optical fiber and the host are tightly connected together, thereby preventing signal interruption accidents caused by poor contact.

Four-Faith Smart Power Fault Indicator has the functions of line load monitoring, short-circuit fault, and ground fault indication, which can help line-finding personnel quickly find fault points, shorten power outage time, and improve power supply reliability. How to choose overhead fault indicator, transient recorder type fault indicator and cable fault indicator?

Cable Fault Indicator

● High-precision real-time sampling technology
● Real-time monitoring of line load changes
● Controllable electric power, high current non-saturation, short-circuit current protection
● WDT watchdog design to ensure system stability
● Support remote management, high efficiency
● Intelligent line fault monitoring
● Support multiple reset methods such as timing and power-on, and remote manual remote control reset is also available

Transient Wave Recording Fault Indicator

● High-speed digital sampling technology
● Integrate the advantages of 4G/3G and LoRa comprehensive communication to ensure that the terminal is always online
● The wire can be used for electricity, and the built-in lithium sub-battery can work stably and reliably for more than 10 years
● Automatic reset, timing reset, remote control reset
● Small current (5A) self-powered design, real-time online stable operation
● Intelligent triggering captures instantaneous current of small current grounding fault and transient waveform signal of electric field to ground

Overhead Fault Indicator

● Integrate the advantages of 4G/3G and LoRa comprehensive communication to ensure that the terminal is always online
● Card line to take power, built-in lithium sub-battery, stable and reliable work > 10 years
● High magnetic permeability cable structure + Four-Faith proprietary algorithm to ensure sampling accuracy and improve fault detection accuracy
● Real-time monitoring of line load changes
● Possess self-test and self-recovery function
● Epoxy pouring, fully sealed structure, suitable for harsh environments