Single-Phase Automatic Circuit Reclosers
Isolates a faulted lateral without dropping the whole feeder
A single-phase fault on a lateral should cost you one phase of one branch, not three phases of the feeder. A single-phase automatic circuit recloser sits on the tap line and clears the transient by itself, which keeps the customers on the healthy phases in service and keeps the substation breaker out of the event entirely.
Maximum voltage options are 8.6, 15, 15.6 and 21.9 kV, with rated current of 400, 630, 800 or 1,250 A and symmetrical breaking from 12.5 kA to 25 kA. The solenoid magnetic actuator has load-break capability, opens in 20 ms or less, closes in 30 ms or less, and is rated for 30,000 mechanical operations on an O-0.5s-CO-2s-CO-5s-CO sequence. Standard frequency is 60 Hz, with 50 Hz available. Three units can be supplied as a ganged three-phase set where the scheme calls for independent single-pole tripping.
Why it matters
Clearing a lateral fault locally means the substation breaker never sees it, so momentary interruption counts on the main feeder stop absorbing branch faults.
Opening in 20 ms or less and closing in 30 ms or less gives fast transient clearing on tap lines where damage accumulates quickly.
30,000 mechanical operations covers the high-cycle duty a rural lateral generates over a 20-year service life.
Three units ganged as a three-phase set deliver independent single-pole tripping without moving to a three-phase device.
The 8.6 to 21.9 kV range covers the common lateral voltages without forcing a custom pole design.
Ratings
Maximum voltage: 8.6 kV · 15 kV · 15.6 kV · 21.9 kV
Rated current: 400 · 630 · 800 · 1,250 A
Short-circuit breaking: 12.5 · 16 · 20 · 25 kA; 12.5 kA short-time withstand on the 15 kV base model
Peak withstand: 31.5 · 40 · 50 · 63 kA
Power-frequency withstand (1 min): 28/36 kV to 45/55 kV depending on pole type; 50 kV on the 15 kV base model
BIL: 95 kV to 195 kV depending on pole type
Operating sequence: O-0.5s-CO-2s-CO-5s-CO
Mechanical life: 30,000 operations
Opening / closing time: ≤20 ms / ≤30 ms
Mechanism: Solenoid / magnetic actuator with load-break capability
Frequency: 60 Hz (50 Hz available)
Combination: Three units can be supplied as a ganged three-phase set for independent single-pole tripping
Standards
IEEE C37.60
IEC 62271-111
Applications
Single-phase laterals and spurs
Rural feeders
Single-pole trip and reclose schemes
Transient fault clearing on tap lines
Questions engineers ask
Can single-phase reclosers be used for a three-phase circuit? Yes. Three units can be supplied as a ganged three-phase set, which gives independent single-pole tripping on each phase. That keeps two healthy phases in service during a single-phase-to-ground fault, something a gang-operated three-phase device cannot do. Ratings, sequence and mechanical life stay the same as the individual unit.
What short-circuit rating is available at 15 kV? Symmetrical breaking options across the range are 12.5, 16, 20 and 25 kA, with peak withstand of 31.5, 40, 50 and 63 kA. The 15 kV base model is specified with 12.5 kA short-time withstand and 50 kV power-frequency withstand for one minute. Basic impulse level runs from 95 kV to 195 kV depending on the pole type selected.
