What Is Power System Protection, Why Is It Required and Some Basics?

Power system protection systems are referred to as secondary equipment, as the primary equipment is transformers, lines, generators, capacitors, breakers, disconnectors. In the normal state of a power system, there is a balance of electric energy sufficient to meet the needs of the connected load, and the power system operating quantities such as voltages, currents, and frequency, are all within the design ratings of the primary equipment. Power systems are designed, planned, and constructed to limit failure modes and equipment damage and thereby enhance overall system reliability. In the electrical power industry, protective relays monitor power system quantities such as current, voltage, impedance, and frequency. Power system protection engineering is a specialty within the discipline of electrical engineering. Reliability refers to the ability of the protective system to operate correctly at all times. Protection system dependability is achieved by ensuring that the protective relays and their application within the overall protection system operate when required.