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 series, & SJ600, bus differential, transformer differential etc), Voltage operated (VAGM, VD, 7RW 600), relays requiring voltage & current inputs (CDV, 7SJ531, 7SA etc).
Testing instruction for CDG relays.
- Test to be done in accordance with commissioning instruction for above relays for non-directional & directional inverse time over current and earth fault relay with MRI 220C.
- Reading obtained during testing should be recorded in commissioning test.
- For permissible variations in current please refer of commission manual.
- The above mentioned commissioning instructions & commissioning test report should be referred to by commissioning engineers where these relays are to be tested & commissioned.
- Where necessary depending on customer’s equipment & manual consent on Test/Formats etc. suitable test procedure may be adopted after documenting the consent.
- Manufactures test recommendations shall be final in case of any disagreement / ambiguity.