Current transformer CT secondary open circuit solution
Current transformer CT secondary overvoltage protector prevents the principle of secondary open circuit of current transformer CT
The 1 loop meter indicates an abnormality, which is generally reduced or zero. The open circuit of the current loop used for the meter will make the three-phase ammeter indication inconsistent, the power meter indication decrease, and the meter speed slow or not. If there is no such indication when the meter is indicated, it may be in a semi-open state (poor contact).
2 Current transformer CT body has no noise, uneven vibration, severe heat, smoke, etc. Of course, these phenomena are not obvious when the load is small.
3 Current transformer CT secondary circuit terminal, component wire head has discharge and sparking phenomenon.
4 If the relay fails or is rejected, this situation can be detected and handled during a false trip or a step-by-step trip.
5 electricity meters, relays, etc. smoked. The burnout of the relay with the power meter and the meter, the transmitter of the remote device, and the protection device not only makes the CT open twice, but also causes the PT to be short-circuited twice.
Conclusion and troubleshooting:
The above is some basic clues to check the CT secondary open circuit. In normal operation, the primary load is not large, the second time is no work, and when the current loop is not measured, the secondary open circuit fault of the current transformer model CT is not Easy to find. Check the processing of the current transformer CT secondary open circuit fault, to minimize the primary load current to reduce the voltage of the secondary circuit. Pay attention to safety during operation. Stand on the insulation mat, wear insulated gloves, and use well-insulated tools.
(1) When the CT secondary open circuit is found, it is necessary to distinguish between which group of current loop faults, open phase differences, and whether there is any influence on the protection, report scheduling, and release the protection that may be misplaced.
(2) Minimize the primary load current. If the CT is seriously damaged, the load should be transferred and the power should be cut off. Current transformer CT secondary overvoltage protector to prevent the current transformer CT secondary open circuit principle
(3) Try to short-circuit the CT twice with a good short wiring on the nearest test terminal as soon as possible, and then check the open circuit point.
(4) If a spark is found during the short circuit, the short circuit should be valid. The fault point should be in the loop below the short contact point and can be further searched. If there is no spark when shorted, the short circuit may be invalid. The fault point may be in the loop before the short contact point. The short contact point can be changed forward point by point, and the range check can be narrowed.
(5) Within the scope of the fault, the terminals and components that are prone to failure should be inspected. For the faults that are detected, they can be handled by themselves, such as loose external parts such as terminal blocks, poor contact, etc. If the open circuit point is on the terminal block of the current transformer model body, it should be powered off. If it is not possible to handle it by itself (such as inside the relay) or if it is unable to identify the fault by itself, the CT should be short-circuited and reported to the superior.