Protection against electrical hazards, faults and mis-operations in electrical installations

The subject of protection in the industry and electrical installations is vast. It covers many aspects:

• Protection of the persons and animals against electrical shocks
• Protection of the equipment and components against the stresses generated by short-circuits, lightning surges, power-system instability, and other electrical perturbations
• Protection of the property and equipment against damages and destructions
• Protection against the production losses
• Protection of the workers, the surrounding population and the environment against fire, explosions, toxic gases, etc.
• Protection of the operators and of the electrical equipment from the consequences of incorrect operations. This means that the switching devices (Load break switches, disconnectors, earthing switches) must be operated in the right order. Suitable Interlocking ensures strict compliance with the correct operating sequences.

Four aspects of the protection are detailed in the scope of this guide:

• Protection against electrical shocks
• Protection of the transformers against external constraints and internal faults
• Improvement of MV/LV transformer protection with circuit breaker associated to self powered relay
• Protection of the operators against the consequences of incorrect operations by appropriate interlocks.