Overview
When a fault occurs at the T-junction of a 12kV overhead distribution line or at the end user’s premises, the coordination of the operation time of the incoming switch protection and the outgoing switch protection at the substation may not be properly set, resulting in the substation’s outgoing switch tripping. If the nature of the fault is permanent, the reclosure at the substation will fail, leading to a power outage for the entire 12kV distribution line due to a localized incident within a medium-voltage user boundary.
If an outdoor boundary circuit breaker is installed at the T-junction or at the user end (responsibility boundary point), it can automatically isolate the fault (such as overload, short circuit, or single-phase grounding) after confirming that a fault has occurred within the user boundary. This ensures that non-faulty users can continue to receive power normally.
The ZW32-12M outdoor high-voltage permanent magnet vacuum circuit breaker applied to the 12kV feeding overhead line can prevent unnecessary power outages for fault-free lines, reduce the range of fault-related power outages, shorten user outage times, and protect the safe operation of the main grid. It also possesses fault detection, protection control, and communication functions, allowing for automatic elimination of single-phase grounding faults and automatic isolation of phase-to-phase short-circuit faults. The installation point can be at the responsibility boundary of the 12kV distribution line user’s incoming line, and it can also be suitable for branch line connection points that meet the requirements.