Switchyard Equipment For Itc Munger.docx

.2.2 ISOLATORS a. All isolators should be provided with padlocking in the fully open and fully close positions. b. Electrical or castle key interlock should be provided between the breaker and its associated isolators so that the isolators can be closed or opened only when the breaker is open. c. Earth blade should be provided on the line side isolator. The isolator and the corresponding earth blade should be so interlocked such that the earth blade cannot be closed unless the isolator is open and vice versa. Earth blades can also be provided on load side based on the system specific design. For further details please refer CBIP Manual on substation layout. d. Earth blade should be provided with pad locking in the open and closed positions. 4.4.2 ISOLATORS a. Annual checks: i. Clean the isolator and check for smooth operation; ii. Clean and grease the operating mechanism; iii. Clean isolator contacts and remove fused material, if any; iv. Check the isolator finger contact compression; v. Tighten isolator arm clamping bolts; vi. Post insulators Clean and check for damage/crack Tighten all bolts and nuts vii. Lubricate the rotating shaft and all pins in the operating mechanism; and viii. Check tightness of terminal connections and earth connections.

4.2.4 LIGHTNING ARRESTERS a. Pressure relief device. b. Discharge counter with leakage current detector and bypass copper shunt.

c. Insulated conductor for connecting the lightning arrester earth terminal to the discharge counter. 4.4.4 LIGHTNING ARRESTERS a. Annual checks i. Clean the porcelain housing; ii. Check for any tracking on the porcelain housing due to flash over; iii. Check the tightness of line terminal and earth connections; and iv. Records the reading of discharge counter and leakage current ammeter.

4.3. COMMISSIONING CHECKLIST FOR OUTDOOR ISOLATORS PHYSICAL CHECKS a. Check name plate details according to specification b. Check for any physical damage c. Check tightness of all bolts, clamps and connecting terminals d. Check cleanliness of insulators e. Check operation and interlocks f. Check earth connection of operating handle and structure g. Check simultaneous closing of all the three poles COMMISSIONING TESTS a. Measure insulation resistance of each pole b. Check contact resistance between male and female contacts

4.6. COMMISSIONING CHECKLIST FOR OIL IMMERSED TRANSFORMER PHYSICAL CHECKS a. Check name plate details with the specification b. Check for any physical damage, in particular of bushing

c. Check tightness of all the bolts, clamps and connecting terminal d. Check cleanliness of bushing e. Check oil leakage and oil level f. Check breathing condition, weather, that breathing line is free, silica gel is reactivated, oil is available at the bottom g. Check for clearance, particularly in case of bus ducts h. Check earthing of transformer tank, neutral bushing, marshalling box, separately mounted radiated bank etc. i. Ensure that all coolers and cooler header valves are opened j. Released air from bushing if applicable (very important) and Buchholz relay k. Check the bushing horn gap, if applicable l. Check that the transformer is correctly installed with reference to its phasing COMMISSIONING TESTS a. Test the transformer oil for dielectric strength, tan-delta, acidity, resistively and dissolved gases b. Test the bushing oil for dielectric strength, if applicable c. Insulation test of windings (including tertiary winding, if applicable) d. Test the transformer for the following e. i. Voltage / turns ratio at all the taps ii. Winding resistance at all the taps iii. Short circuit impedance at full winding iv. Magnetic balance at full winding v. Core loss at service tap at low voltage vi. Capacitance and tan delta vii. Polarisation index (PI) Vector group test Vector group test

Corporate EHS A.4ANNEXURE f. Phase sequence test g. Current transformer, if any i. Continuity test ii. Polarity test iii. Insulation resistance test iv. Ratio test v. Secondary winding resistance h. Line connections as per phasing diagram i. Insulation resistance of control wiring j. Buchholz relay operation (for alarm and trip) k. OLTC control, indicating and alarm circuits, if OLTC is provided l. AVR relay settings to be verified (if OLTC is provided). Check automatic operation of AVR in test mode. m. Operation test of all protective devices and interlocks. n. Cable terminations are carried out as per approved cable interconnection schedules. o. Calibration of temperature indicators (oil and winding) p. Cooling system q. i. Fans and motors rating and fan mounting (whenever applicable) ii. Operation of valves iii. Operational test of cooling equipment iv. Check fan motors for insulation, continuity, vibrations, temperature rises, and direction of rotation Check the lightening arrestor installation