16-09-2016, 01:56 PM
1454914838-FEEDERPROTECTIONRELAYS.docx (Size: 453.77 KB / Downloads: 4)
Objective
1. Feeder is the line that transfers the power from source end to the distribution end.
2. To have a uninterrupted power supply for consumers, feeders need to be protected from various faults using different schemes.
Introduction
1. The word FEEDER may be referred as the connecting link between the two circuits. The feeder could be in the form of transmission line that is short, medium, or long or this could be a distribution circuit.
2. Feeders form the integral part of power system, as power is transferred through feeders from source to load.
3. Hence it is important to protect feeders from faults for continuous supply of power to consumers.
Need for protection
Following conditions lead to various faults:
Over loading
1. Over voltage
2. Under Frequency
3. Power Swings Transient Faults
4. Permanent Faults
5. Atmospheric Conditions(Temperature, Lightening)
6. Short circuit Faults
Methods of protection of feeder
Non Unit Type Protection:
1. Time-graded over-current protection
2. Current-graded over current protection
3. Distance protection
Unit Type Protection:
1. Differential protection
2. Carrier-current protection