Causes and solutions for sudden tripping of high-voltage switchgear
Nov 25, 2020
High-voltage switchgear is a common equipment in power stations, and its role is very important. So what if it trips?
The significance of high-voltage switchgear maintenance
1. High-voltage switchgear is widely used in power distribution systems to control and protect circuits.
2. Once the high-voltage switchgear fails, it will cause a large-scale blackout.
3. Due to the complex structure of the high-voltage switchgear and the various failure modes, it is more difficult to judge where it fails.
4. Only by accurately determining the type of failure, the cause of the failure, and performing maintenance in a timely manner, the maintenance personnel can shorten the outage time and restore normal power supply.
Causes and performance of sudden tripping of high voltage switchgear
1. The high-voltage cabinet is equipped with over-current, quick-break, gas and temperature protection devices. When the line or transformer fails, the protective relay will trip the switch. This fault is mainly caused by electrical protection.
2. After the trip, the green light of the switch cabinet will start to flash. If there are audible and visual alarm signals in the high-voltage switchgear or central signal system, the relay indicator will give a prompt; if the computer monitoring system has a "protective effect", then it is a tripping situation caused by the switch displacement caused by the combination change.
Fault Judgment of Sudden Trip of High Voltage Switchgear
1. This fault can be judged based on the loss of the relay card and remote signaling information.
2. In the high-voltage switchgear, after activating the gas and temperature protection, there will be a corresponding signal relay indicating that the card has been closed.
3. When the overcurrent relay is working, it is impossible to distinguish between overcurrent and quick-break. But in the definite time protection circuit, overcurrent and quick-break are respectively protected by two current relays. When the relay is working, the red LED lights up, which can clearly determine the cause of the failure.
Treatment of Sudden Tripping Failure of High Voltage Switchgear
1. Due to line overload, the action of the overcurrent relay causes the switch to trip. Before powering on, you should consider reducing or balancing the load to prevent tripping again after power on.
2. When the fast circuit breaker trips, check the bus, transformer and related lines, find the short-circuit fault point, and eliminate the fault before sending power.
3. The relay can be reset after the overcurrent and quick-break protection trips the high-voltage switchgear. Using this method, it can be distinguished from temperature and gas protection.
4. When the transformer has an internal fault or overload, the gas and temperature protection will play a protective role. If the internal failure of the high-voltage switchgear causes heavy gas to run, then a relatively large maintenance should be performed on it. If the new transformer has a slight gas effect, it can release the internal gas and continue operation.
