The understanding of the five defenses of electrical power system
1. Prevent mis-opening and closing of circuit breakers.
2. Prevent the disconnector from being divided and closed with load.
3. Prevent the grounding switch from being closed with load.
4. Prevent grounding from opening and closing the circuit breaker.
5. Prevent mistakenly entering the live interval.
Conventional anti-mistaken locking device.
Mechanical interlocking. When the grounding switch and circuit breaker are in the open position, the handcart can be moved from the test displacement to the working positionWhen the grounding switch is in the closing position, the handcart cannot be moved from the test displacement to the working position;
The grounding switch can only be operated when the trolley is in the test position or in the away position.
The circuit breaker handcart can only be plugged in and released when the test and disconnection position are in place, and the secondary plug can be locked and cannot be lifted due to the mechanical interlocking effect when the circuit breaker handcart is in the working position.
When the grounding switch is equipped with a locking solenoid, the grounding switch can only be operated when the control power supply is put into operation and the high-voltage side is not energized.
After the circuit breaker trolley closes in the test position, the trolley circuit breaker cannot enter the working position (to prevent closing with load).
When the grounding knife is in the closing position, the trolley circuit breaker cannot enter and close (to prevent closing with the grounding wire).
The grounding knife cannot be put into operation when the circuit breaker is closed (to prevent the grounding wire from being hooked up live).
The circuit breaker cannot exit the working position of the trolley circuit breaker when the closing operation is working (to prevent the load broach switch).
The circuit breaker cannot open the cable room door (to prevent inadvertent entry into the live interval) when the circuit breaker is in closed operation
Electrical interlocking. When the circuit breaker is in the broken state, the adjacent cabinet isolation trolley on the circuit can be shaken.
When the isolation trolley is in the "working" position, the circuit breaker can be closed in the adjacent cabinet of the circuit.
When the bus is electrified, the isolation trolley cannot be shaken out and shaken in.
When the bus is live, the grounding switch cannot be operated.
In the same section of the medium voltage cabinet, only one of the circuit breakers of the listed electrical inlet and the inlet circuit breaker of the oil engine can be closed.
Two mains incoming circuit breakers (or diesel engine inlet circuit breakers) and contact switches, 3 circuit breakers can only close 2 at the same time.
When the contact switch is in the open state, the bus tie isolation circuit breaker can be shaken out for operation.
When the bus tie isolation circuit breaker is in the working position, the contact circuit breaker can be closed.
Key interlock. Used to ensure that a particular device or system is operating in the correct order under certain conditions. It restricts the operation of the equipment by using a combination of keys and locks, preventing incorrect operation or the occurrence of dangerous situations. When using a key interlock system, the operator must use the correct key in the prescribed order of operation to ensure the safe operation of the equipment. This avoids potential hazards, damage to equipment, or causing accidents.
Electromagnetic interlocking. Electromagnetic interlocks typically contain the following main components:
Electromagnets: Electromagnets in electromagnetic interlocking systems are critical components. It usually consists of a coil and an iron core, and when energized, a magnetic field is generated, which attracts or releases the corresponding mechanical device to achieve interlocking control of the device.
Mechanism: A mechanism is a part that works with an electromagnet to connect or release a device. Common mechanical devices include push rods, deadbolts, rockers, etc., when the electromagnet is energized, they will be affected by the electromagnetic force and move, realizing the interlocking of the equipment.
Control circuits: Electromagnetic interlocking systems are usually equipped with corresponding control circuits to control the energizing and power-off of the electromagnet. This can be achieved through buttons, switches, sensors, etc., to ensure that the electromagnet has the effect of attracting or releasing at the right time.
Safety detection device: To ensure safety, electromagnetic interlock systems are usually equipped with safety detection devices that are used to detect the status or position of the equipment. For example, proximity sensors or limit switches can be used to monitor whether the device is in the correct position and thus control the action of the solenoid.
Electromagnetic interlocks are commonly used in areas such as machinery and equipment, industrial production lines, and safety doors to ensure the safety and sequence of operation of equipment or areas. Through reasonable design and configuration, it can realize the interlocking of equipment, prevent operators from misoperation in unsafe situations, and reduce the occurrence of accidents.