Analysis Of Five - Guard Interlocks In Power System
The realization of “five prevention” function has become one of the important measures of electric power safety production. With the continuous development of the power grid, the technology is constantly updated, and the error prevention device is constantly improved and perfected. The design principle of error proof device is: any high voltage electrical equipment that may cause error operation should be equipped with error proof device and corresponding error proof electrical locking circuit.
The power system in the five prevention
1. prevent the wrong division, close circuit breaker.
2. prevent load close disconnecting switch.
3. prevent live hanging (close) grounding wire (grounding switch).
4. prevent with grounding wire (grounding switch) close circuit breaker (disconnecting switch).
5. Prevent straying into the charged interval.
“Five defenses” of high voltage switch cabinet
After the vacuum breaker car in the high voltage switchgear closes at the test position, the car breaker cannot enter the working position. (prevent closing with load)
When the grounding cutter in the high voltage switchgear is in position, the car circuit breaker cannot enter the closing. (prevent closing with grounding wire)
When the vacuum circuit breaker in the high voltage switch cabinet is closed, the backdoor of the cabinet shall be locked by the machine on the earth cutter and the cabinet door. (prevent straying into charged interval)
The vacuum circuit breaker in the high voltage switchgear closes when working, and the grounding cutter cannot be put in. (prevent grounding wire from being charged)
The vacuum circuit breaker in the high voltage switch cabinet cannot exit the working position of the trolley circuit breaker when the circuit breaker is closed. (prevent pull brake with load)
1. Prevent straying into the charging interval
2. Prevent the grounding wire from closing
3. Prevent closing with load
4. Prevent live grounding wire
5. Prevent pulling brake with load
High – pressure switch cabinet operation of the five – defense
Five defense, usually refers to the high voltage switch cabinet “five defense” or power distribution room “five defense one pass”.
1. Prevent load and disconnecting switch. (circuit breaker, load switch, contactor close state cannot operate disconnecting switch.)
2. Prevent misclassification and misconnection of circuit breakers, load switches and contactors. (only the operation instruction corresponds to the operating device can operate on the operated device)
3. Prevent the grounding switch from closing the circuit breaker and load switch when it is in the closed position. (only when the earth switch is in the state of disconnecting, can the disconnecting switch or handcart enter the working position, and can the circuit breaker and load switch be closed)
4. Prevent the earth switch from being misconnected when it is charged. (the disconnecting switch or handcart shall be operated only when the breaker is in the tripping state and shall be withdrawn from the working position to the test position and the earth switch shall be closed)
5. Prevent straying into the charging interval.(Only when the compartment is not charged can the door be opened into the compartment)
Substation “five prevention” that is, fire, waterproof, lightning, snow, prevent small animals. “Pass” means keep well ventilated.
The design principle of error proof device is: any high voltage electrical equipment that may cause error operation should be equipped with error proof device and corresponding error proof electrical locking circuit.