Rittal cabinets – judgment and handling of high-voltage switchgear closing faults

Closing faults can be divided into electrical faults and mechanical faults. There are two types of closing methods: manual and electric. Failure to close manually is generally a mechanical failure. Manual can be closed, electric can not close is an electrical fault.

1. Protection action: The protection action has been analyzed in front to trip the switch. Before the switch is transmitted, the circuit has a fault protection circuit to make the anti-trip relay function. The switch trips immediately after closing. Even if the transfer switch is still in the closing position, the switch does not close again and jump continuously.

2. Protection failure: Now the high-voltage cabinet is set up with five anti-function, which requires the switch not to be in the running position or the test position can not be closed. That is, the position switch is not closed, and the electric cannot be closed. This kind of failure is often encountered during closing. At this time, the running position light or the test position light is not illuminated. Move the switch trolley slightly so that the limit switch can be closed to send power. If the limit switch is offset too far, it should be adjusted.

3. Electrical interlocking faults: In the high-voltage system, some electrical interlocks are set up for the reliable operation of the system. For example, in a single-bus segmentation system with two power supply inlets, it is required that only two switches can be combined between the two-way inlet cabinet and the bus connection cabinet. If all three are closed, there will be a danger of reverse power transmission. And the short-circuit parameters change, and the short-circuit current of parallel operation increases. (The interlocking circuit of the incoming cabinet is connected in series with the normally closed contact of the bus-linked cabinet, and the incoming cabinet can be closed in the open state of the bus-linked cabinet.) The interlocking circuit of the bus unit is connected in series with one normally open and one normally closed of the two incoming cabinets respectively, and then connected in parallel. In this way, it can ensure that the bus cabinet can only be powered when one of the two incoming cabinets is closed and the other is opened. When the high-voltage cabinet cannot be electrically closed, the first thing to consider is whether there is an electrical interlock, and it cannot be blindly closed manually. Electrical chain faults are generally improper operation and cannot meet the closing requirements. For example, although the incoming cabinet is divided and closed, the handcart in the opening cabinet is pulled out and the plug is not plugged in. If the interlocking circuit fails, you can use a multimeter to check the fault location. It is simple and convenient to use red and green lights to determine the fault of the auxiliary switch, but it is not very reliable. It can be determined with a multimeter check. The method of overhauling the auxiliary switch is to adjust the angle of the fixed flange, adjust the length of the connecting rod of the auxiliary switch, etc.

4. Control loop open circuit fault: In the control loop, the control switch is damaged, the line is broken, etc., so that the closing coil can not be powered. At this time, there is no sound of the closing coil moving. There is no voltage at either end of the measuring coil. The inspection method is to check the open path point with a multimeter.

5. Closing coil failure: Closing coil burning is a short circuit fault. At this time, there are peculiar smells, smoke, and shortening of insurance melting. The closing coil is designed for a short working time, and the power-on time should not be too long. After the failure of closing, the cause should be found in time, and the closing should not be repeated many times. In particular, the closing coil of the CD type electromagnetic operating mechanism is easy to burn out due to the large passing current and multiple closing. When repairing the fault that the high-voltage cabinet cannot be closed, the method of trial power transmission is often used. This method can eliminate line faults (except transformer temperature and gas faults), electrical chain faults, and limit switch faults. The fault site can basically be determined inside the handcart. Therefore, in the emergency treatment, it can be used to test the power transmission at the test position and replace the power transmission method of the spare handcart. This results in more with less and reduces the duration of power outages.

Rittal cabinets – judgment and handling of high-voltage switchgear closing faults

Rittal cabinets – judgment and handling of high-voltage switchgear closing faults

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