POWER HOUSE

DESIGN OF POWER HOUSE Important considerations in design:- safety of personal equipment. reliability and security. possibility to expand. ease in maintenance.

COMPONETS OF POWER HOUSE: SURGE ARRESTORS OR LIGHTARRESTER CURRENT TRANSFORMER (C T ) CIRCUIT BREAKER POTENTIAL TRANSFORMER (P T ) POWER TRANSFORMER RELAY WAVE TRAP BUS BAR ISOLATER

SURGE ARRESTORS OR LIGHTARRESTER:NING Surge Arresters or Lightning Arresters discharge the over voltage surges to earth and protect the equipment insulation from switching surges and lightning surges. Surge arresters are generally connected between phase conductor and ground. In a Substation surge arrester is located at the starting of the substation as seen from incoming transmission lines and is the first equipment of the substation. Surge arresters are also provided near the transformer terminals phase to ground.

CURRENT TRANSFORMER (C T ) Current transformers (CT): The lines in substations carry currents in the order of thousands of amperes. The measuring instruments are designed for low value of currents Current transformers are connected in lines to supply measuring instruments and protective relays. For example a 100/1A CT is connected in a line carrying 100A, and then the secondary current of CT is 1A. Current transformers are used for Stepping down current for measurement, protection and control.

POTENTIAL TRANSFORMER (P T ) Potential transformers (PT): The lines insubstations operate at high voltages. The measuring instruments are designed for low value of voltages. Potential transformers are connected in lines to supply measuring instruments and protective relays. These transformers make the low voltage instruments suitable for measurement of high voltages. For example a 220 kV/110V PT is connected to a power line and the line voltage is 220 kV then the secondary voltage will be 110V. Voltage transformers are used to step down the voltage for measurement, protection and control. Voltage transformers are of two types. 1 Electromagnetic type 2 Capacitive VT located on the feeder side of the Circuit Breaker. Potential transformers

POWER TRANSFORMER Power Transformers are used to step up or step – down a.c. voltages and to transfer electrical power from one voltage level to another. Tap changers are used for voltage control. Transformers range in size from thumbnail-sized units hidden in microphones to units weighing hundreds of tons used in the power grid. A wide range of transformer designs are used in electronic and electric power applications.

TRANSFORMER

PROTECTION OF POWER TRANSFORMER USING BUCHHOLZ RELAY In the field of electric power distribution and transmission, a Buchholz relay is a safety device mounted on some oil-filled power transformers and reactors, equipped with an external overhead oil reservoir called a conservator. The Buchholz Relay is used as a protective device sensitive to the effects of dielectric failure inside the equipment

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