MV/LV Switchboards in general
Depending on the size of the building or factory site and whether the supply is high voltage or low voltage, there may be requirements for both a main high voltage switchboard and one or more low voltage switchboards or just a single low voltage switchboard. The preferred name for the switchboard unit is a “Switchgear and Controlgear Assembly” (SCA).
The basic aim of the switchboard is to take the electrical power from the main supply source and then to feed or distribute power to the appropriate circuits within the building. The switchboard has to perform this function in such a way that there is proper control of power flow and proper electrical protection against the damaging effects of faults.
This protection is necessary to prevent personnel hazards and also equipment hazards and possible fires. It should be able to operate to isolate a faulty section in the minimum possible time consistent with the fault severity.
Components of MV and LV Switchboards
LV and MV are different despite they may look very similar. One thing they do the same is that they distribute electrical energy, but using different voltage levels. MV will always supply LV switchbord, never vice versa.
1. The major components of a MV switchboard:
- The incoming cables
- Outgoing circuit conductors
- Knife switch
- Load-break switch
- Earthing switch
- Circuit breaker
- Protection relays
2. The major components of a LV switchboard: