The FZW28-12 (FFK) type 12KV outdoor high-voltage user boundary load switch is an automatic isolation protection system device with intelligent control, commonly known as the watchdog negative (FZW28-12F), abbreviated as FFK.

FZW28-12 outdoor high-voltage user boundary load switch is suitable for single grounding protection of branch line users of 12KV outdoor AC overhead distribution branch lines. It is suitable for neutral point ungrounded and neutral point grounded through inductance
A 12KV, 50Hz three-phase distribution network with ground and neutral points grounded through a small resistor. The fault definition of the FFK load switch on the incoming and outgoing sides, where the incoming side fault load switch does not trip; The unidirectional grounding fault load switch on the outgoing side tripped before the higher-level equipment; After the overcurrent fault load switch on the output side trips with the higher-level equipment, the fault section is isolated after the higher-level equipment recloses. This not only determines the scope of the fault, but also ensures the normal operation of non faulty lines, which is of great significance for improving power supply reliability.

FZW28-12 Outdoor High Voltage User Boundary Load Switch