High Voltage Disconnect Switch Configuration Selection

Selection of isolating switch
High Voltage Disconnect Switch is configured on the main wiring to ensure that a clear break is formed and the live parts are isolated during the maintenance of the line and equipment. Since the isolating switch has no arc extinguishing device and has low breaking capacity, the switching operation sequence must be followed when operating the isolating switch, that is, when supplying power, first close the isolating switch on the bus side, then close the isolating switch on the line side, and finally close the circuit breaker. The power outage is the opposite of the above.
Configuration of isolating switch
1. Isolating switches should be configured on both sides of the circuit breaker to form a clear break and isolate the power supply during the maintenance of the circuit breaker.
2. Ordinary transformers with direct neutral grounding should be grounded through isolating switches.
3. The lightning arrester and voltage transformer on the bus should share a set of isolating switches to ensure the safety of the maintenance of electrical appliances and busbars. 1-2 sets of grounding switches should be installed on each section of the busbar.
4. The lightning arrester connected to the transformer lead or neutral point does not need to be equipped with an isolating switch.
5. When there is no power supply on the user side of the feeder line, the circuit breaker does not need to be equipped with an isolating switch on the side leading to the user. However, it can be installed to prevent lightning overvoltage.
Isolating switch selection
Rated voltage:
Isolating switch rated voltage (KV) = circuit nominal voltage * 1.2/1.1 times.
Rated current:
The rated current standard value should be greater than 150% of the maximum load current.
Rated thermal stability current:
Select a rated thermal stability current value greater than the system short-circuit current.