Commissioning Procedures for Protection Relays On Site

Commissioning Procedures for Protection Relays

Pre commissioning check/Instruction of Protection Relays Refer to Siemens protection relays:- Check the relay model number (type number) is as per specifications. Note the serial no of the relay of the relay. Inspect the relay for signs of physical damage. Check that any series resistors, where applicable, have been installed e.g. for CTMM relays a series resistor is required in the power circuit, depending on the supply voltage. Test the relay as per the procedure for the given relay. Protection relays can be divided in to current operated ( eg- CDG…

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Testing of Stability of Transformer Differential Scheme

Testing of stability of transformer differential Scheme

Guidelines of transformer differential stability check Transformer above 2 MVA are normally provided with differential protection scheme. The relay can be of static type(DTH31- Alsthom) or numerical type( 7 UT- Sag ) The relays have to be tested as per the procedure mentioned in manuals.The procedure mention below enables the testing engineer to confirm the correctness wiring. Expected short circuit current can be calculated from the % impedance of the transformer. e.g. Consider a transformer of 10 MVA, 132 KV /11 KV, % impedance – 13 % Calculated primary full load current…

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Commissioning of isolators and earthing switches

Commissioning of isolators and earthing switches

Guidelines of Commissioning of isolators Some of the important guidelines to be followed before energizing the isolators and earthing switches. For your reference, please find below the step by step process of commissioning of isolators: Isolators can be of the following types Centre break Double break Pantograph Operation of isolators can be motorized or manually operated. The nameplate details of an isolator consists of rated current, rated voltage, short circuit current rating, the auxiliary voltage required for operation etc. For a motorized isolator closing & opening is normally controlled by ‘close’,…

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Commissioning Procedure for Electric HT Motor

Commissioning Procedure for Electric HT Motor

Quick Guidelines of Industrial Electric HT Motor Pre-Commissioning checks:- Check for the proper fixing motor on the foundation. Check that the motor can be easily turned over by hand. Check motor winding resistance on each phase; verify that they are equal. IR value and PI value of the motor to be checked. IR values and HV test on the cable to be performed. Check all the tripping and alarm signals from winding and bearing TRDs (through scanner if provided) Testing of ht motor protection relay and tripping of the circuit breaker…

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Commissioning Procedure for HV / HT Cable

HT-CABLE

Step by step Commissioning guidelines of HV/ HT Cable Check continuity of the HT cable to confirm R, Y  and B phase at both ends as per marking. This is especially important when there is more than one run of cable phase; any cross-over will result in a dead  short circuit. The Cable screen is to be earthed at one end only. Cable gland plate should be of non- magnetic type e.g. aluminum. Perform HV / HT test on the cable.Apply only Dc voltage, as cables have relatively higher capacitance. Check…

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