Tutorial IEEE 1427 Standard- Substation Insulation Coordination

Session two of a four part series, helps the audience to better understand the concepts of electrical clearance, the calculation of BIL, BSL, and insulation coordination. Most substations are located in fenced-off areas above ground. In cities substations may be constructed in buildings or underground. Energized conductors and connecting buswork within a substation or switchyard are usually bare (non-insulated) and are installed on insulators that provide insulation from the ground. Insulation from other energized and grounded objects is provided by proper air distances (clearances). Sufficient clearances among ground and various energized air-insulated equipment are required to prevent (minimize the probability of) sparkovers and flashovers which would disrupt the operation and integrity not only of the affected equipment but also of the entire or large parts of the electric power system. IEEE Std 1427-2020 “IEEE Guide for Recommended Electrical Clearances and Insulation Levels in Air Insulated Electrical Power Substations” provides the required information.