ZW20-12F/630A integrated primary and secondary intelligent sectionalizing switch, 10kV pole-mounted intelligent vacuum circuit breaker

The ZW20-12 indoor high-voltage sectionalizing vacuum circuit breaker is a circuit protection device used at the user sectionalizing points of 10kV distribution networks. It consists of a circuit breaker body, a fault detection controller and an external voltage transformer. Common models include ZW20-12F, ZW20A-12, etc., with a rated voltage of 12kV, suitable for power grid systems with ungrounded neutral points or grounded via arc suppression coils.

This circuit breaker adopts vacuum arc extinguishing and SF6 gas insulation technology. The sealed box structure has explosion-proof performance and environmental adaptability, and can operate at -40℃ to +40℃. It integrates intelligent sectionalizing functions, identifies internal and external line faults through milliampere-level zero-sequence current detection technology, and automatically cuts off single-phase grounding and phase-to-phase short circuits. The main circuit adopts a table-type contact structure to reduce resistance and temperature rise. The spring operating mechanism supports electric/manual operation, with a mechanical life of 10,000 times. It has a built-in current transformer for phase-to-phase protection, and can be equipped with an isolating switch to form a disconnection point, suitable for the construction of smart grids and urban and rural distribution networks.

The ZW20-12 indoor high-voltage sectionalizing vacuum circuit breaker (commonly known as "watchdog") is a circuit protection device used at the user sectionalizing points of 10kV distribution networks. It is mainly composed of three parts: the ZW20-12 vacuum circuit breaker body, a fault detection controller and an external voltage transformer. The three parts are electrically connected through aviation sockets and outdoor sealed control cables.

Common models include ZW20-12F/630-20, ZW20A-12/630-20, ZW20B-12/630-20, ZW20AF-12/630-20, etc. Its main rated parameters are rated voltage 12kV, rated frequency 50Hz, rated current usually 630A, 1000A or 1250A, and rated short-circuit breaking current usually 20kA or 25kA.

In the model meaning, ZW represents outdoor vacuum circuit breaker, 20 represents the design serial number, 12 represents the rated voltage of 12kV, and F represents having intelligent sectionalizing function. The numbers after the slash such as 630, 1000, 1250 represent the rated current, in amperes (A); the numbers after the hyphen such as 20, 25 represent the rated short-circuit breaking current, in kiloamperes (kA).

The ZW20-12 indoor high-voltage sectionalizing vacuum circuit breaker is mainly composed of three parts: the ZW20-12 vacuum circuit breaker body, a fault detection controller and an external voltage transformer. The circuit breaker body adopts a three-phase common box structure, and the box is filled with SF6 gas as the insulating medium. The incoming and outgoing line insulating sleeves are integrally cast with epoxy resin and silicone rubber. Phases A and C adopt corner sleeves to reduce the volume.

The structure of the circuit breaker body consists of a conductive loop, an insulation system, seals and a housing. The conductive loop is formed by connecting the incoming and outgoing line conductive rods, conductive clamps, soft connections and the vacuum arc extinguishing chamber. The operating mechanism is electric energy storage, electric opening and closing, and also has manual energy storage, manual opening and closing functions. The entire structure is composed of closing springs, energy storage systems, overcurrent trip coils, opening and closing coils, manual opening and closing systems, auxiliary switches, energy storage indicators and other components.

In the circuit breaker body, one current transformer is configured for each of phases A and C, with transformation ratios such as 400/5 or 600/1, for phase-to-phase protection. One zero-sequence current transformer with a transformation ratio of 20/1 is configured in the circuit breaker body to detect milliampere-level zero-sequence current. The operating power can be an external AC or DC 220V power supply, or obtained from the 10kV line through an external operating power transformer/voltage transformer.

Some products can be equipped with external three-phase linkage isolating switches and lightning arrester post insulators. The product is equipped with an explosion-proof device and a flip-type explosion indicator.