- System voltage: System voltage will be known. The recloser must have a voltage rating equal to system voltage.
- Maximum fault current available at the recloser location: Maximum fault current will be known or can be calculated. The recloser interrupting must be equal to (or greater than) the maximum available fault current at the recloser location.
- Maximum load current: The recloser continuous current rating must be equal to(or greater than) anticipated circuit load. For series-coil-type reclosers, the coil size can be selected to match the present load current, the anticipated future load current, or the substation transformer capacity.
Generally, a trip-current value of at least twice the expected load current is used.
- Minimum-fault current within the zone to be protected: Minimum fault current that might occur at the end of the line section must be checked to confirm that the recloser will sense and interrupt this current.
- Coordination with other protective devices on both the source and the load sides of the recloser.
Generally,recloser timing and sequences are selected to coordinate with the source-side devices.
Figure show several options to locate reclosers in a MV system.