Power module/SST medium voltage input solution

Miniaturization is the key to current prefabricated modular solutions, and the miniaturization of vacuum circuit breakers makes medium voltage power control more flexible. Whether it is SST or source grid load storage, it solves the problems of large air gap requirements and difficult arc extinguishing caused by high voltage.

The integrated distribution module combines high voltage, transformer, and low voltage, among which the low installation density on the high voltage side, large space requirements, and high degree of internal arc fault damage directly limit the high integration and system safety of prefabricated power modules.

Whether it is a voltage input of 13.8kV or 34.5kV, the basic electrical theory requires a large air gap. For example, 13.8kV requires an air electrical gap of not less than 160mm, and 34.5kV requires a gap of not less than 320mm. This means that the size of the switchgear is very large.

The use of load switch fuses as the front-end control and protection switch cabinet for transformers requires a larger size and is not conducive to remote control. The circuit breaker is designed with full solid insulation

The maintenance of power modules requires electrical isolation and protective grounding on the high-voltage incoming line side, and the mechanical isolation fracture is the most important safety guarantee facility. The vacuum fracture cannot be used as an isolation fracture, and must be opened by an isolation switch or pulled out to the test position by a handcart device to form a visible mechanical fracture.

The fixed installation size of the isolation switch and vacuum circuit breaker is small, and the size can be reduced by gas insulation and other methods. The 13.8kV 600A cabinet has a depth of 900mm and a width of 400mm, which is smaller than the low-voltage switchgear. The problem is that the circuit breaker cannot be replaced after failure, and the entire cabinet needs to be replaced, which is time-consuming and costly.

Air insulated withdrawable switchgear effectively solves the above problems, with miniaturized vacuum circuit breakers. The 13.8kV 600A cabinet can reach a width of 500mm and a depth of 1200mm, which is close to or smaller than the size of low-voltage switchgear

Excellent electric field design, full tube busbar, and primary circuit system ensure that the entire switchgear is in a uniform electric field environment. Even if the distance is not large, it can withstand high voltage under a uniform electric field without worrying about discharge and aging risks.

Clear compartment design, all metal partitions, metal valves, and safety locks ensure safe operation

The vacuum fracture withstand voltage of the circuit breaker meets the requirements of isolation fracture withstand voltage, realizing hot standby of the switchgear. Two incoming circuit breakers are used for outdoor backup. After a fault, the withdrawable circuit breaker can be quickly pulled out of the cabinet for replacement, greatly reducing the power outage time. Equipment maintenance, opening the vacuum circuit breaker, shaking it out to the test position, and closing the grounding switch can safely and securely perform maintenance on the transformer and low-voltage equipment behind it.

Lightweight operating mechanism, highly integrated system, circuit breaker with built-in monitoring, protection tripping, remote status monitoring. One circuit breaker can include traditional circuit breakers, current transformers, microcomputer protection devices, etc. for the entire outgoing circuit, making the switchgear simpler, with higher installation density, more flexible layout, and smaller size.

The supporting voltage transformer handcart, power transformer handcart, etc. are all compact designs that achieve the same cabinet size. The modular design can also be combined with circuit breaker compartment modules to form a cabinet, enabling voltage measurement, control of power supply, and flexible one-time solutions.

High voltage arc protection system, ultra fast 5ms arc extinguishing, quick power cut-off, no damage to itself and subordinate equipment, quick restoration of power supply after clearing faults, segmented and partitioned protection can also achieve power continuity.

It is not just about piecing together traditional standard medium voltage switchgear, transformers, and low voltage switchgear to create a new type of power module, or placing standard medium voltage switchgear at the front end of a solid-state transformer to meet SST requirements from high voltage to 800V. It is necessary to customize and design medium voltage solutions based on performance, safety, operation and maintenance, cost, and other aspects, truly achieving a highly integrated system design.