Power Distribution Protection Elements
A typical power distribution network, consist of distribution substations, the primary and secondary feeders, distribution transformers and other secondary networks. There are different modes of operation designed and implemented to allow for redundancy supply in the event of faults or maintenance. Despite the rapid advancements in power systems, the worth of distribution networks is fairly large and there is a need for sophisticated protection schemes which ensure safety against ever present insulation failures. In this regard Engineers have developed various protection zones and complex schemes which involve various configurations of protection elements.
- Surge arrester
- Fuses
- Protection Relays
Surge arrester
A surge/lightning arrester is used to protect the equipment from impulse surges due to switching, faults or lightning events. They are used above 1 kV and are connected in shunt format with various electrical nodes. When an impulse voltage spike occurs, the
arrester is activated and diverts the path of the surge down to the ground.
Fuse
While it comes to the protection devices, the fuse tops the list. Small sized wire and glass fuses are common and are employed in the protection of our laptop chargers. On the other hand, power fuses are large, the HV fuses in distribution systems are known as distribution cutouts. A protection engineer carefully selects the fuses and keeps various factors in mind while selecting a system. Such factors involve voltages, scope, and magnitude of fault current that might occur in any system.
Protection Relay
Relays are discrete protection components which have two states of working, “on” and “off”. The old generation of relays were actuated by an electromagnet coil whereas modern relays are microprocessor based. They are very useful devices since various elements can be combined to achieve various on and off functions.