Views:154 Author:Site Editor Publish Time: 2021-04-20 Origin:Site
The working principle of the cable fault indicator is that when the line has a short-circuit fault, the short circuit fault indicator gets a fault current, and the display screen of the fault indicator will change from white to red. The cable fault indicator used to test the location of the cable fault is composed of the core processor and some necessary auxiliary components, which improves the accuracy and fluency of the instrument.
The line fault indicator is an important equipment that can intelligently judge, detect and locate power grid operation faults according to the changes in current and voltage in the power grid. It is usually installed in the transmission network and is mainly used to monitor and detect possible short circuits and single-phase grounding faults in the line. When a short circuit occurs in the power network, the current value in the line suddenly changes, and the fault current passing the indicator will trigger the indicator's flop, and the non-fault current will not affect its normal display. Most of the power fault indicators are equipped with an automatic delay reset function. When the fault is eliminated, the power transmission will be restored, and the fault indicator will automatically reset to prepare for the next inspection, which makes the daily inspection and maintenance of the power grid more convenient and faster.
At present, the two types of faults that are most likely to occur in power network transmission are inter-phase short circuit and single phase grounding. Therefore, the ground fault indicator is also designed according to these two types of faults. Phase-to-phase short circuit refers to the contact between two or three phases of the transmission line, which causes the occurrence of line short circuit fault. When a short circuit occurs between phases, the instantaneous current in the line suddenly increases and a current jump is formed. The earth fault indicator sets the current mutation value inside. If the current change exceeds the set value, the fault current indicator will display corresponding fault signal. For the judgment basis and principle of single-phase grounding, the zero-sequence current amplitude method is the most commonly used, that is, collecting temporary current, voltage and other data values in the distribution network where the neutral point is not directly grounded, and then adopting the steady-state zero sequence fundamental waves or higher harmonics of current and voltage to calculate and analyze the collected data to determine the current and voltage values in the line. If it is a fault current, it will light up, otherwise the fault path indicator will not change.
The power line fault indicator is an instrument that transmits, receives and digitizes signals with a microprocessor as the core.
The cable fault indicator and the microprocessor complete the signal digitization process. It can also have a communication port and PC communication for work feedback of signal processing results.
In the cable fault indicator, the pulse generator is an auxiliary instrument that automatically converts the encoded signal transmitted by the microprocessor into a logic pulse of a certain width. The pulse generator converts the transmitter circuit into a high radiation emission pulse and transmits it to the tested cable
The high-speed A/D generator of the cable fault indicator is transmitted to the microprocessor for analysis and processing.
The keyboard is a window for human-computer interaction. The operator can input the commands required for testing through the keyboard and transfer them to the computer. Finally, the cable fault indicator is controlled by the computer.