Addition of foreign projects

Foreign projects require mechanical key interlocking, and foreign customers have relatively high safety requirements. In addition to the conventional five proof mechanical interlocking required in China, padlocks and industrial safety key locks must also be equipped.

For the central cabinet, for safety reasons, the customer requires that the circuit breaker and grounding switch must be operated by closing the door. Therefore, the mechanical interlock for closing the door must be configured. To avoid manually opening the high-voltage contact valve, there must be mechanical interlocking to ensure that the valve can only be opened by a handcart with functions such as circuit breakers.

The padlock mainly includes the cover plate for the rocking hole of the circuit breaker, the cover plate for the grounding switch operation hole, and the high-voltage chamber door, all of which require the installation of a safety padlock with a locking rod diameter of 8mm to ensure the requirement of additional locking during installation and maintenance.

Safety interlock technology can ensure that personnel can only operate dangerous machinery and equipment under pre-set procedures. The next step of operation can only be carried out under safe conditions to ensure the safety of personnel and machines to the greatest extent possible. A key box will also be used to exchange one or several keys for multiple other keys, ensuring all logic between the switchgear cabinet itself, cabinets, and between the high and low voltage sides of the switchgear and the transformer compartment door. By using mechanical key exchange, the requirements of power plant safety management can be achieved, and electrical equipment can be operated correctly. At the same time, the mechanical logic switch of the mechanical interlocking device should have expandable space, which can realize the interlocking of new electrical equipment and original system electrical equipment, and achieve the "five prevention" of the entire system.

Each section of the busbar is equipped with a grounding switch, and maintenance of the busbar does not require the use of a grounding handcart. The busbar grounding switch enables direct grounding during maintenance and repair of the main busbar, which is simpler and more convenient. The grounding switch is installed on the upper part of the main busbar room, and can be operated in front of the cabinet or electrically. Similarly, grounding switches are also installed for incoming cabinets to achieve grounding of incoming cables and compartments for safety protection.

The IEC market application of busbar side current transformers also requires the installation of current transformers on the busbar side of the busbar circuit breaker cabinet for differential protection;

The top pressure relief switchgear must have an anti internal fault level, generally requiring A FLR, consistent with the product's breaking current, and a time of 1 second.

Foreign customers may also request the provision of ARS. Generally, for 25kA and below, a baffle form, namely SKIRT type ARS, can be used.

For 31.5kA, a buffer type ARS, namely ARC APPROBER, is used.

At the same time, some projects are affected by the height of the switch room, and it is necessary to avoid personnel injury caused by the rebound of flames after reaching the roof. Some customers require no fire or objects with fire to be sprayed out. They need to use dedicated pressure release channels to release the pressure and arc generated by internal faults outdoors, or use arc absorbers made of a large amount of ceramic fillers to filter fire and airflow, minimizing harm to personnel.

Signage and signs are required for switchgear to have clear markings to ensure customer safety and correct operation, generally including danger, warning, caution, instructions, and other markings. The logo must be made according to customer requirements or relevant ISO 3864 standards, such as high voltage hazards.

Excessive operation instruction labels should be reduced, and the content should be concise and to the point, emphasizing special attention that needs to be paid. For example, if the circuit breaker handcart is damaged by excessive operating force during rocking, a label with "operating torque ≤ 25N. m" can be added at the rocking hole.