Massachusetts Electric Company Nantucket Electric Company Each d/b/a National Grid D.P.U. 18-150 Attachment AG-13-37-3 Page 1 of 20 SUBSTATION MAINTENENCE Doc. # SMP 402.02.2 Procedure Page 1 of 20 2.5 to 14.9MVA (Base Rating) Version 3.0 – 05/28/13

INTRODUCTION This procedure describes the methods used to perform Visual and Operational, DGA and TCG, In Service, Diagnostic, Acceptance, and other inspections on small, power used in electrical substations. PURPOSE Scheduled equipment inspections are necessary to protect both the public and electric utility workers, prevent unnecessary customer outages, and maximize equipment operating life. This procedure lists special tools and equipment required, unusual hazards, and methods used, to inspect small power transformers. ACCOUNTABILITY Substation or other Supervisors supervising inspection and maintenance activities. Substation or other Workers performing inspection and maintenance activities. COORDINATION Acceptance Inspection - Relay Department needed to check current transformers, fault pressure relay and low oil tripping. Diagnostic Inspection New England - Laboratory needed to perform Frequency Response Analysis (FRA) test, 115 kV and above. REFERENCES National Grid Safety Handbook Manufacturer’s Installation, Operating, and Maintenance manuals for the specific equipment to be inspected. Manufacturer’s operating manuals for the specific test equipment to be used. SMP407.05.2 - Potential Devices (Inspected at the same time as power transformers) SMP 412.01.3 - Load Tap Changers (LTC) (Inspected at the same time as power transformers) SMP 419.01.2 - Surge Arresters (Inspected at the same time as power transformers) DEFINITIONS DGA - – Analysis of the gases in insulating oil. Used for early detection of transformer problems and after suspected internal faults. DGA tests can detect overheating, corona and arcing, seal failure and water. FRA - Frequency Response Analysis – Electrical test to determine mechanical movement or damage in transformers. Leakage Reactance - Electrical test to determine winding distortion in transformers.

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LTC - Load Tap Changer – Tap changer capable of operation while the transformer is energized and under load. Operates automatically to compensate for changes in source voltage and load current to maintain constant voltage to customers DETC - De-energized (No Load) Tap Changer – Tap changer that is only operated while the transformer is de-energized. Set at installation and rarely changed. Oil Screen test - Laboratory test of , usually a quart sample, for low dielectric, particles, contaminants, inhibiter, degradation, acids, PCB’s and water. Silica Gel - Crystalline material capable of absorbing moisture. Used in free breathing transformers and tap changers to remove moisture from the air entering the oil space. Surge Arrester - Lightning arrester. Used to protect transformers and other equipment from high voltage transients caused by lightning and system disturbances. TRAINING Not Applicable.

DOCUMENT CONTENTS Table of Contents

1.0 TEST EQUIPMENT REQUIRED ...... 3

2.0 MATERIALS REQUIRED ...... 3

3.0 SPECIAL SAFETY EQUIPMENT REQUIRED...... 4

4.0 VISUAL AND OPERATIONAL INSPECTION ...... 4

5.0 DIAGNOSTIC INPSECTION ...... 7

6.0 INTERNAL INSPECTION...... 12

7.0 ACCEPTANCE TEST...... 13

8.0 DGA SAMPLE...... 13

9.0 OTHER TESTS AND INSPECTIONS...... 14

10.0 APPENDIX A - VACUUM/PRESSURE BLEEDER TEST SETUP...... 15

11.0 REVISION HISTORY ...... 17

PRINTED COPIES ARE NOT DOCUMENT CONTROLLED. FOR THE LATEST AUTHORIZED VERSION PLEASE REFER TO THE APPROPRIATE DEPARTMENT WEBSITE OR DOCUMENTUM. File: SMP 402.02.2 TRANSFORMER 2.5 TO 14.9MVA Originating Department: Sponsor: Substation Work Methods Susan Fleck Massachusetts Electric Company Nantucket Electric Company Each d/b/a National Grid D.P.U. 18-150 Attachment AG-13-37-3 Page 3 of 20 SUBSTATION MAINTENENCE Doc. # SMP 402.02.2 Procedure Page 3 of 20 Transformer 2.5 to 14.9MVA (Base Rating) Version 3.0 – 05/28/13

1.0 TEST EQUIPMENT REQUIRED

1.1 V&O Inspection 1.1.1 Digital Multi-meter, ANS/ISA Class IV 1.1.2 Spare batteries for multi-meter 1.2 Diagnostic Inspection 1.2.1 All in V&O and In Service Inspections above plus: 1.2.2 Vacuum/Pressure Bleeder test setup. See Appendix A 1.2.3 Power factor test set such as the Doble M4000. Check for AC power cable, ground and test leads. 1.2.4 Leakage reactance test set. Doble M4110 Leakage Reactance Interface for M4000 1.2.5 Frequency Response Analysis test set. 1.2.6 Temperature gauge test set - Check for correct temperature well insert. 1.3 Acceptance Inspection 1.3.1 All Above Plus. 1.3.2 Turns Ratio test set - Check test leads. 1.3.3 Dew point test set. 1.3.4 Meg-ohm meter – 5000V. Check battery charged AC power cable and test leads. 1.3.5 test equipment. Brought by relay department. 1.3.6 Fault pressure relay test equipment. Brought by relay department. 1.3.7 Special Tools Required. a. None

2.0 MATERIALS REQUIRED

2.1 V&O Inspection 2.1.1 Mobile Device with National Grid V&O software installed. 2.1.2 Inspection data from last V&O inspection. 2.1.3 Binoculars 2.1.4 Spare nitrogen tank, regulator and gauges, and tank dolly. 2.1.5 Spare dry (blue) silica gel. 2.1.6 Spare filters for LTC oil processing systems.

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2.2 DGA Sample 2.2.1 Oil sampling syringe, box, and transmittal sheet. 2.2.2 Spare brass drain valve plugs 3/4”, 1”, 1 1/2”, and 2” 2.2.3 Barb hose adapter with 3/4”, 1”, 1 1/2”, and 2” brass reducing fittings. 2.2.4 Oil absorbent pads. 2.2.5 Waste oil container and automotive type oil drain pan with funnel. Automotive type drain pans are low enough to fit under most oil drain valves without tipping. 2.2.6 Vacuum/pressure relief device test setup. See Appendix A 2.3 Diagnostic Inspection 2.3.1 All in V&O and In Service Inspections above plus: 2.3.2 Inspection card/record from last diagnostic inspection. 2.3.3 Doble Power Factor Test Setups booklet. 2.4 Acceptance Inspection. 2.4.1 All of the above. 2.5 Other Tests 2.5.1 Oil Quality a. All required for DGA sample except syringe. b. At least two new, clean quart oil sample bottles.

3.0 SPECIAL SAFETY EQUIPMENT REQUIRED

3.1 Uni-Hoist Fall arrest system. 3.1.1 Adapter plates transformer to Uni-Hoist 3.1.2 Handhold to Uni-Hoist mounting kit. Arms, nuts, bolts, spacers. 3.1.3 Winch assembly. 3.1.4 Post assembly 2 pieces. 3.2 Fall arrest harness. 3.3 Retractable fall arrest lanyard.

4.0 VISUAL AND OPERATIONAL INSPECTION

4.1 Follow-up work orders shall be generated for any problems found that were not corrected during the V&O Inspection. 4.1.1 The Supervisor reviewing the V&O Inspection results is responsible for generating the follow-up work orders.

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4.2 Check for abnormal noise. 4.2.1 Pinging, gurgling, and other unusual noises. Abnormally loud humming. If power transformers are making unusual noise leave the area immediately and contact the dispatch center and your supervisor. 4.3 Check bushings for: 4.3.1 Surface contamination, dirt, rust, salt, etc. 4.3.2 Evidence of tracking. 4.3.3 Chipped or cracked porcelain. 4.3.4 Discoloration of, or heat rising from, bushing connections (overheating). 4.3.5 Leaking oil or compound. 4.3.6 Oil level in oil filled bushings. Lack of visible oil requires immediate attention. 4.3.7 Squirrel guards (bushings smaller than 23kV) 4.4 Check transformer tank. 4.4.1 Mechanical relief device - indicator button popped up or semaphore up indicates an operation. 4.4.2 Pressure relief rupture disk intact. Sometimes found on very old transformers. Located the end of a large pipe on top of the main tank. 4.4.3 Ground connections. 4.4.4 Leaks. Dripping or flowing oil requires immediate attention. 4.4.5 Blistering paint or other signs of overheating. 4.4.6 Deteriorating paint and/or rusting. 4.5 Check radiators. 4.5.1 Leaks. Dripping or flowing oil requires immediate attention. 4.5.2 Deteriorating paint and/or rusting. 4.5.3 Debris blocking air flow. 4.5.4 Make fans on all banks on. a. Check for all fans operating. b. Check for missing/damaged fan guards. c. Check for noisy (bearings, misaligned blades) fans. 4.5.5 Switch primary fans group. 4.5.6 Make fans auto. 4.6 Check gauges 4.6.1 Record LTC counter, indicating and drag hands. Reset drag hands.

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4.6.2 Check transformer oil level. Level should be above the 25°C mark unless the transformer oil temperature is below 25°C. Level at or below the LO mark requires immediate attention. 4.6.3 Check transformer oil temperature. 4.6.4 Check all winding temperatures. 4.6.5 Check combustible gas gauge, if equipped. 4.6.6 Check strike counters, if equipped. 4.7 Check control cabinet for: 4.7.1 Moisture and water. 4.7.2 Door gasket deterioration. 4.7.3 Deteriorating paint and/or rusting. 4.7.4 Missing insect screens 4.7.5 Unsealed conduits. 4.7.6 Cabinet light working. 4.7.7 Heaters on below 40°F. a. Apparatus may have a combination of thermostatically controlled heaters and heaters that are on continuously. Check the wiring diagram. 4.8 Check and Test Alarms 4.8.1 Record any alarm indications. a. Reset alarm indications. 4.8.2 Put the annunciator’s Low Oil level switch in the test position. a. Verify the dispatcher received the alarm. b. Put the switch back in the in service position (ON). 4.8.3 Verify all alarms in service (ON), Check with your supervisor before restoring alarms that are off. 4.9 Check oil preservation systems, if equipped. 4.9.1 Nitrogen blanketed systems. a. Nitrogen tank (high pressure gauge) above 200 psi Change cylinder if below 200 psi. Record pressure. b. Transformer tank (nitrogen tank low pressure gauge) approximately 2 1/2 to 3 psi Pressures below 0.2 psi or above 5.5 psi, require immediate attention. Record reading. 4.9.2 Free breathing systems. a. Breather openings clear and screened.

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b. Silica gel indicator. Should be blue, changes to pink as it absorbs moisture. 4.9.3 Sealed systems. a. Positive tank pressure, 1.5 to 3 psi in Gas/Oil Sealed (two tank systems). b. Tank pressure, +5 to -5 psi in sealed (vacuum/pressure gauge) systems. 4.10 Perform Associated Equipment V&0 Inspections. 4.10.1 See SMP 407.01.2 - Bushing potential devices, if equipped. 4.10.2 See SMP 412.01.2 - Load Tap Changers (LTC), if equipped. 4.10.3 See SMP 419.01.2 - Surge Arresters.

5.0 DIAGNOSTIC INPSECTION

5.1 Complete all outstanding work orders. 5.2 Test vacuum/pressure bleeder and gauge. 5.2.1 See Appendix A at the end of this document for test setup details. 5.2.2 Save and replace the plastic pipe caps when done. This will prevent bits of foam etc. from contaminating the test set. 5.2.3 If pressure is less the 2 psi positive add nitrogen to bring up to 2 psi. 5.2.4 Test the vacuum-pressure gauge. a. If the following are done reasonably quickly the nitrogen lost will not be significant. b. Open the test kit ball valve. c. Unscrew the vacuum-pressure bleeder. d. Clean any old Teflon tape or pipe dope out of the fitting. e. Screw in the test kit ball valve. Do not use Teflon tape. f. Close the test kit ball valve. g. Screw the pipe plug into the test kit tee fitting on gauge assembly. Do not use Teflon tape. h. Connect the test kit barb adapter on the gauge assembly to the test kit ball valve with tubing and open the test kit ball valve. i. Compare the test kit vacuum-pressure gauge with the transformer tank gauge. j. They should agree within 1/2 psi 5.2.5 Close the test kit ball valve. 5.2.6 Remove the vinyl tubing from the ball valve, leave on gauge assembly. 5.2.7 Test the vacuum-pressure bleeder.

PRINTED COPIES ARE NOT DOCUMENT CONTROLLED. FOR THE LATEST AUTHORIZED VERSION PLEASE REFER TO THE APPROPRIATE DEPARTMENT WEBSITE OR DOCUMENTUM. File: SMP 402.02.2 TRANSFORMER 2.5 TO 14.9MVA Originating Department: Sponsor: Substation Work Methods Susan Fleck Massachusetts Electric Company Nantucket Electric Company Each d/b/a National Grid D.P.U. 18-150 Attachment AG-13-37-3 Page 8 of 20 SUBSTATION MAINTENENCE Doc. # SMP 402.02.2 Procedure Page 8 of 20 Transformer 2.5 to 14.9MVA (Base Rating) Version 3.0 – 05/28/13

a. Clean any old Teflon tape or pipe dope off of the vacuum/pressure bleeder. b. Screw the vacuum-pressure bleeder into the test kit tee fitting on gauge assembly. Do not use Teflon tape. c. Connect the vacuum port of the vacuum-pressure pump to the gauge assembly with the vinyl tubing. d. Pump the vacuum-pressure tester while watching the test kit gauge. When the vacuum stops increasing the vacuum bleeder has opened. e. Vacuum should be 5 psig plus or minus 1/2 psig. f. Move the vinyl tubing from the vacuum port of the vacuum-pressure pump to the pressure port. g. Pump and release the vacuum-pressure tester while watching the test kit gauge. When the pressure stops increasing the pressure bleeder has opened. The pressure can be increased by pressing on the pump plunger on the back of the tester. h. Pressure should be 5 psig plus or minus 1/2 psig. i. Adjust the vacuum-pressure bleeder if necessary, with the 5/64” Allen wrench. j. The pressure adjustment is located on one side of the vacuum/pressure bleeder; the vacuum adjustment is on the other. k. Reinstall the bleeder on the transformer l. If Teflon tape is used make sure last thread is showing and there are no hanging Teflon threads. 5.3 Perform Associated Equipment V&0 Inspections. 5.3.1 See SMP 407.01.2 - Bushing potential devices, if equipped. 5.3.2 See SMP 412.01.2 - LTC, if equipped. 5.3.3 See SMP 419.01.2 - Surge arresters. 5.4 Perform all of the items listed in Visual and Operational, and In Service Inspections above. 5.5 Perform winding power factor tests. 5.5.1 Refer to the Doble M4000, instruction books and the Doble Test Setups booklet. 5.6 Perform excitation test. 5.6.1 Refer to the Doble M4000, instruction books and the Doble Test Setups booklet. 5.6.2 On LTC equipped transformers test tap 16 lower and all taps from 1 lower to 16 raise. 5.7 Perform Bushing Power Factor Tests. 5.7.1 Do C1 and C2 tests on all bushings with capacitance or power factor taps. If transformer is equipped with bushing pot devices, the C2 cord shall be removed

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from the bushing voltage tap prior to power factor testing. Do not test thru the C2 cord. The C2 voltage tap shall be cleaned, dried and inspected. 5.8 Perform the following if requested by Substation Work Methods. These tests may be requested after fault operations or other unusual events. 5.8.1 Perform FRA test. a. Refer to the instruction book for the FRA test set being used. 5.8.2 Perform Leakage Reactance test. 5.8.3 Refer to the instruction book for the FRA test set being used. 5.9 Verify operation of temperature gauges and contacts. 5.9.1 Use the Jofra temperature gauge test set to test the oil temperature gauge and all winding temperature gauges. 5.9.2 Find the lowest micro switch setting on each gauge. Usually small silver pointers, with small clamp screws, on gauge face. Note: some of the micro switches in the gauge may not be used. Refer to the transformer prints for the switches used and their function. 5.9.3 Set the Jofra 10° below this temperature. 5.9.4 Allow the gauge’s sensing bulb to cool below this temperature. 5.9.5 Insert the sensing bulb into the Jofra temperature well. Use the correct well insert. If the insert is the wrong size readings won’t be accurate. 5.9.6 Slowly increase the Jofra temperature allowing the temperature gauge to stabilize. 5.9.7 Verify that fan and pump banks turn on at the correct temperature. 5.9.8 Verify high oil temperature and high winding temperature alarms. High Oil alarm should be 100°C; High winding temperature alarm should be 120°C. 5.9.9 When stabilized the gauge should agree with the temperatures set in the Jofra within ± 7°C. 5.10 Test all alarms. 5.10.1 Warning – Shutting off fans and pumps may trip some transformers and mobiles 5.10.2 Notify the dispatch center that you will be sending alarms. 5.10.3 Test Low Oil Level Alarm. a. Put the annunciator’s Low Oil level switch in the test position. b. Verify the dispatcher received the alarm. c. Put the switch back in the in service position (ON). 5.10.4 Test loss of flow alarm, if equipped. a. Put the annunciator’s Loss of Flow switch in the test position.

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b. Verify the dispatcher received the alarm. c. Put the switch back in the in service position (ON). 5.10.5 Test fans, loss of AC, alarm. a. Put the annunciator’s Loss of AC switch in the test position. b. Verify the dispatcher received the alarm. c. Put the switch back in the in service position (ON). 5.10.6 Test the high oil temperature alarm, if equipped. a. Put the annunciator’s High Oil Temperature switch in the test position. b. Verify the dispatcher received the alarm. c. Put the switch back in the in service position (ON). 5.10.7 Test high winding temperature alarm, if equipped. a. Put the annunciator’s High Winding Temperature switch in the test position. b. Verify the dispatcher received the alarm. c. Put the switch back in the in service position (ON). 5.10.8 Test nitrogen alarm bottle pressure alarm. a. Shut off nitrogen bottle valve. b. Shut off nitrogen valve closest to tank. c. Crack fitting on nitrogen system side of valve. d. Allow pressure on high pressure nitrogen gauge to bleed down to 180 psi. Then tighten fitting. e. Verify the dispatcher received the alarm. 5.10.9 Test nitrogen low pressure alarm, if equipped. a. Crack fitting on nitrogen system side of valve again. b. Allow pressure on low pressure nitrogen gauge to bleed down to 1 psi. Then tighten fitting. c. Verify the dispatcher received the alarm. 5.10.10 Test nitrogen high pressure alarm, if equipped. a. Open nitrogen bottle valve fully. b. Adjust regulator until low pressure nitrogen gauge reads 6 psi. The nitrogen pressure relief valve may open. If it lifts before 4 ½ psi or above 5 ½ psi it should be adjusted to lift at 5 psi c. Verify alarm on annunciator, or with dispatch center. d. Crack fitting on nitrogen system side of valve again.

PRINTED COPIES ARE NOT DOCUMENT CONTROLLED. FOR THE LATEST AUTHORIZED VERSION PLEASE REFER TO THE APPROPRIATE DEPARTMENT WEBSITE OR DOCUMENTUM. File: SMP 402.02.2 TRANSFORMER 2.5 TO 14.9MVA Originating Department: Sponsor: Substation Work Methods Susan Fleck Massachusetts Electric Company Nantucket Electric Company Each d/b/a National Grid D.P.U. 18-150 Attachment AG-13-37-3 Page 11 of 20 SUBSTATION MAINTENENCE Doc. # SMP 402.02.2 Procedure Page 11 of 20 Transformer 2.5 to 14.9MVA (Base Rating) Version 3.0 – 05/28/13

e. Adjust regulator until low pressure nitrogen gauge reads 3 psi. f. Tighten fitting. Check for leaks with Leak Check. g. Open valve to transformer tank fully. h. Verify the dispatcher received the alarm. 5.11 Visually inspect the equipment for rust, corrosion, and excessive fading. 5.11.1 Excessive fading is defined as fading to the point underlying primer is visible 5.11.2 Touch up corrosion by performing light sanding or brushing followed by paint if temperature is above 45°F. a. Company policy allows the preparation of surfaces for painting when previously painted with lead based paint. b. Refer to the National Grid Lead Compliance Plan for details when working with surfaces that may contain lead. 5.11.3 Utilize Strathmore Paint W80-0225 Base White (Dove Gray Color) or equivalent for transformer light grey applications and SAP # 9309442 paint for dark grey applications. 5.12 Verify primary, secondary and ground connections physically when work is completed. 5.12.1 All primary connections connected and tight. 5.12.2 All secondary connections connected and tight. 5.12.3 All system ground connections connected and tight. 5.12.4 External core ground, if equipped, connected and tight. 5.13 Perform LTC internal inspection, if equipped. See SMP 412.01.2 5.14 Perform surge arrester diagnostic inspection see SMP 419.01.2 5.15 Perform bushing potential device diagnostic inspection, if equipped. See SMP 407.01.2 5.16 Low Side Circuit Breaker, if equipped. 5.16.1 Perform Apparatus or Diagnostic inspection if mobile substation required. 5.16.2 Use applicable Circuit breaker SMP and CMMS Procedures. a. The following drawings do not require review. b. Once again seller shall supply Dept. Name data. 5.17 GE Butyl Power Transformer (PT’s) and Circuit Transformers (CT’s) 5.17.1 If GE Type Butyl PT’s or CT’s are installed within the zone of protection assess condition and determine age. a. If either condition (cracks, etc.) or age (greater than 30 years old) are determined, replace the PT’s and CT’s.

PRINTED COPIES ARE NOT DOCUMENT CONTROLLED. FOR THE LATEST AUTHORIZED VERSION PLEASE REFER TO THE APPROPRIATE DEPARTMENT WEBSITE OR DOCUMENTUM. File: SMP 402.02.2 TRANSFORMER 2.5 TO 14.9MVA Originating Department: Sponsor: Substation Work Methods Susan Fleck Massachusetts Electric Company Nantucket Electric Company Each d/b/a National Grid D.P.U. 18-150 Attachment AG-13-37-3 Page 12 of 20 SUBSTATION MAINTENENCE Doc. # SMP 402.02.2 Procedure Page 12 of 20 Transformer 2.5 to 14.9MVA (Base Rating) Version 3.0 – 05/28/13

6.0 INTERNAL INSPECTION

6.1 Internal inspection tests are only done if problems are found during Diagnostic Testing. Specific tests required will depend on the problems found. All tests are done if an Acceptance Test is being performed. 6.2 Remove low oil tripping 6.3 Perform turns ratio test before moving de-energized tap changer. 6.3.1 Test and record all three phases primary to secondary windings. 6.3.2 Test and record all three phases primary to tertiary windings, if equipped. 6.3.3 Compare to nameplate for selected tap position. 6.3.4 Retest TTR on the “As Left” tap if the de-energized tap changer is disturbed. 6.4 Perform winding resistance test. 6.4.1 Test only on normal, in-service tap. 6.5 Check de-energized tap changer. 6.5.1 Valtec Boroscope may be needed. 6.5.2 Contact pressure and condition. 6.5.3 Operate and check alignment. 6.6 Check operation of oil level gauge alarm and trip contacts. 6.6.1 This test is to be done by the relay department. 6.7 Perform core ground insulation test. 6.7.1 The core ground connection is a small (1’’ to 3”) bushing usually located on the side of the transformer tank in newer transformers. In older transformers it is located under one of the handhold covers on top of the transformer. 6.7.2 Disconnect the core ground from the transformer tank. 6.7.3 Test the insulation resistance (megger) from the core ground to the transformer tank or system ground at 1000 volts. 6.7.4 Reading should be at least 100 megohms. 6.8 Inspect mechanical relief device alarm contact, if equipped. 6.8.1 The alarm micro switch is located under the top dome and can be reached without disassembling the device. 6.8.2 Manually trip the mechanical relief alarm micro switch. 6.8.3 Verify that the dispatcher received the alarm. 6.8.4 Reset the micro switch. 6.9 Inspect Windings, Leads, Blocking, Core. 6.9.1 Windings

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a. Evidence of corona or arcing. b. Distortion or other damage. c. Loose, displaced, or damaged blocking d. Clamping pressure. 6.9.2 Leads a. Evidence of corona or arcing. b. Damaged or missing insulation. c. Lead dressing from ground and other conductors. d. Evidence of overheated connections. 6.9.3 Core a. Evidence of overheating, corona or arcing. b. Distorted or damaged laminations. c. Loose core bolts 6.10 Perform LTC Internal Inspection, if equipped. See SMP 412.01.2. 6.11 Take baseline DGA sample (transformer tank)

7.0 ACCEPTANCE TEST

7.1 See SMP 402.11.2 - Power Transformer Installation and Acceptance Procedure.

8.0 DGA SAMPLE

8.1 Draw a DGA oil sample from main tank and LTC, if equipped, compartments. 8.1.1 Refer to the Transformer Oil Sampling training manual for detailed procedures. 8.1.2 Check for positive pressure in sealed systems. If pressure is less than 2 psi positive add nitrogen to bring up to 2 psi positive pressure. 8.1.3 Remove pipe plug and flush valve. Improper flushing of drain valves will result in bad samples. 8.1.4 Install barb hose adapter and reducer. 8.1.5 Take DGA sample and fill out transmittal paper work. 8.1.6 Put syringe in box after sample is taken. Heat and sunlight can affect DGA samples. 8.1.7 Do not mix-up the load tap changer and transformer tank samples. The load tap changer compartment generally has the load tap changer position indicator mounted on it and generally has a small (3/4” or 1”) drain valve.

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8.2 Schedule three, successive, monthly DGA samples on new installations to check for oil and gas stability. 8.2.1 Replace any iron or galvanized drain valve plugs with brass plugs.

9.0 OTHER TESTS AND INSPECTIONS

9.1 DETC Operation 9.1.1 Perform TTR test before and after changing tap position. 9.2 Oil Quality Test 9.2.1 Refer to the Transformer Oil Sampling training manual for detailed procedures. 9.2.2 Check for positive pressure in sealed systems. If pressure is less than 2 psi positive add nitrogen to bring up to 2 psi positive pressure. 9.2.3 Remove pipe plug and flush valve. Improper flushing of drain valves will result in bad samples. 9.2.4 Install barb hose adapter and reducer. 9.2.5 Take quart oil sample. 9.2.6 Fill out transmittal paper work. 9.2.7 Do not mix-up the load tap changer and transformer tank samples. The load tap changer compartment generally has the load tap changer position indicator mounted on it and generally has a small (3/4” or 1”) drain valve. 9.2.8 Replace any iron or galvanized drain valve plugs with brass plugs. 9.3 Thermographic Inspection. 9.3.1 Check primary and neutral connections. 9.3.2 Check tank for hot spots. 9.3.3 Check fans. 9.3.4 Verify normal operating temperature. 9.3.5 Verify Oil temperature gauge agrees with tank skin temperature within 10 degrees C. 9.3.6 Verify oil flow in radiator fins.

PRINTED COPIES ARE NOT DOCUMENT CONTROLLED. FOR THE LATEST AUTHORIZED VERSION PLEASE REFER TO THE APPROPRIATE DEPARTMENT WEBSITE OR DOCUMENTUM. File: SMP 402.02.2 TRANSFORMER 2.5 TO 14.9MVA Originating Department: Sponsor: Substation Work Methods Susan Fleck Massachusetts Electric Company Nantucket Electric Company Each d/b/a National Grid D.P.U. 18-150 Attachment AG-13-37-3 Page 15 of 20 SUBSTATION MAINTENENCE Doc. # SMP 402.02.2 Procedure Page 15 of 20 Transformer 2.5 to 14.9MVA (Base Rating) Version 3.0 – 05/28/13

10.0 APPENDIX A - VACUUM/PRESSURE BLEEDER TEST SETUP

10.1 Parts Bag 10.1.1 1 ea. - 3/8 brass pipe plug 10.1.2 1 ea. -1/4 brass pipe plug 10.1.3 1 ea. – brass reducer 3/8 female to 1/4 male 10.1.4 1 ea. - brass reducer 3/8 male to 1/4 female 10.1.5 1 ea. - Roll Teflon tape 10.1.6 1 ea. - 5/64” Allen wrench 10.1.7 1 ea. – 1/4 internal plastic pipe cap 10.1.8 1 ea. – 1/4 external plastic pipe cap 10.2 Bleeder Adapter 10.2.1 Qualitrol Vacuum/Pressure gauge S/C 9302812 10.2.2 1 ea. - 1/4” X 1/4” brass, female pipe tee 10.2.3 1 ea. - 1/4” pipe to 1/4” brass hose barb adapter, male pipe end 10.2.4 10 in. - 1/4” ID vinyl tubing 10.2.5 1 ea. – 1/4 internal plastic pipe cap 10.3 Transformer Adapter 10.3.1 1 ea. - 1/4” pipe to 1/4” brass hose barb adapter, male pipe end 10.3.2 8 1/2 in. - 1/4” ID vinyl tubing 10.3.3 1 ea. - 1/4” brass, pipe nipple 2” long 10.3.4 1 ea. - 1/4” pipe X 1/4” brass, pipe ball valve, female ends 10.3.5 1 ea. – 1/4 external plastic pipe cap 10.4 Other 10.4.1 1 ea. – Instruction Card 10.4.2 1 ea. - Automotive vacuum tester, such as a MityVac product (www.mityvac.com) 10.4.3 1 ea. – Spare Vacuum/Pressure Bleeder S/C 9302741

PRINTED COPIES ARE NOT DOCUMENT CONTROLLED. FOR THE LATEST AUTHORIZED VERSION PLEASE REFER TO THE APPROPRIATE DEPARTMENT WEBSITE OR DOCUMENTUM. File: SMP 402.02.2 TRANSFORMER 2.5 TO 14.9MVA Originating Department: Sponsor: Substation Work Methods Susan Fleck Massachusetts Electric Company Nantucket Electric Company Each d/b/a National Grid D.P.U. 18-150 Attachment AG-13-37-3 Page 16 of 20 SUBSTATION MAINTENENCE Doc. # SMP 402.02.2 Procedure Page 16 of 20 Transformer 2.5 to 14.9MVA (Base Rating) Version 3.0 – 05/28/13

Transformer Adapter Bleeder Adapter

Vacuum/Pressure Bleeder Automotive Vacuum/Pressure Pump Bleeder on Adapter

PRINTED COPIES ARE NOT DOCUMENT CONTROLLED. FOR THE LATEST AUTHORIZED VERSION PLEASE REFER TO THE APPROPRIATE DEPARTMENT WEBSITE OR DOCUMENTUM. File: SMP 402.02.2 TRANSFORMER 2.5 TO 14.9MVA Originating Department: Sponsor: Substation Work Methods Susan Fleck Massachusetts Electric Company Nantucket Electric Company Each d/b/a National Grid D.P.U. 18-150 Attachment AG-13-37-3 Page 17 of 20 SUBSTATION MAINTENENCE Doc. # SMP 402.02.2 Procedure Page 17 of 20 Transformer 2.5 to 14.9MVA (Base Rating) Version 3.0 – 05/28/13

11.0 REVISION HISTORY

Version Date Description of Revision 1.0 xx/xx/xx Initial version of document

1.0 12/26/06 Corrected - Formatting Changed - Header title, Document number prefix Removed - Subtitle Changed - First page footer to reference Documentum Changed – References to EOP to SMP Diagnostic Inspection Removed – Leakage reactance test

1.1 02/10/07 Diagnostic Inspection Added – Requirement to Inspect low side circuit breaker

1.2 02/12/07 Diagnostic Inspection Changed – Requirements for FRA and Leakage Reactance testing

1.3 05/23/07 Document Added - Documentum Version # to headers Added - File name to footer

1.4 08/28/07 Visual and Operational Inspection Added – Requirement to generate follow-up work orders Diagnostic Inspection Added – Requirement to complete outstanding work orders Added Requirement to Inspect/correct paint problems

1.5 02/25/08 Diagnostic Inspection Added – Requirement to test excitation on tap 16 lower on LTC transformers

1.6 03/27/08 Other Tests and Inspections Added – DETC Operation Perform TTR test before and after changing tap position.

2.0 06/30/09 Converted document to new EDO format - contents unchanged

3.0 05/28/13 Originating Department - Changed “Substation O&M Services” to “Substation Work Methods” Sponsor - Changed “Donald T. Angell” to “Susan Fleck” References - Changed “National Grid USA Safety Handbook” to “National Grid Safety Handbook” Definitions - Deleted “PDA Training - Changed “N/A” to “Not Applicable” Section 1.2.3 - Changed “Power factor test set Doble M4000 (preferred) or Doble M2H. Check for AC power cable, ground and test leads.” to “Power factor test set such as the Doble M4000. Check for AC power cable, ground and test leads.” Section 2.1.1 - Changed “PDA with National Grid …” to “Mobile Device with National Grid …” Section 4.6 - Replaced Section 4.7.7 - Changed “Heaters on below 40 degrees F” to “Heaters on below 40°F” Section 4.9.1.b - Changed “… Pressures below 0.5 psi or above 5 psi require immediate attention. Record reading.” to “… Pressures below 0.2 psi or above 5.5 psi require immediate attention. Record reading.”

PRINTED COPIES ARE NOT DOCUMENT CONTROLLED. FOR THE LATEST AUTHORIZED VERSION PLEASE REFER TO THE APPROPRIATE DEPARTMENT WEBSITE OR DOCUMENTUM. File: SMP 402.02.2 TRANSFORMER 2.5 TO 14.9MVA Originating Department: Sponsor: Substation Work Methods Susan Fleck Massachusetts Electric Company Nantucket Electric Company Each d/b/a National Grid D.P.U. 18-150 Attachment AG-13-37-3 Page 18 of 20 SUBSTATION MAINTENENCE Doc. # SMP 402.02.2 Procedure Page 18 of 20 Transformer 2.5 to 14.9MVA (Base Rating) Version 3.0 – 05/28/13

Section 4.10.1 - Changed “See SMP 407.05.2 - Bushing potential devices, if equipped.” to “See SMP 407.01.2 - Bushing potential devices, if equipped.” Section 4.10.3 - Changed “See SMP 419.01.3 - Surge Arresters.” to “See SMP 419.01.2 - Surge Arresters.” Section 5.3.1 - Changed “See SMP 407.05.2 - Bushing potential devices, if equipped.” to “See SMP 407.01.2 - Bushing potential devices, if equipped.” Section 5.3.3 - Changed “See SMP 419.01.3 - Surge Arresters.” to “See SMP 419.01.2 - Surge Arresters.” Section 5.5.1 - Changed “Refer to the Doble M4000, M2H instruction books and the Doble Test Setups booklet.” to “Refer to the Doble M4000, instruction books and the Doble Test Setups booklet.” Section 5.6.1 - Changed “Refer to the Doble M4000, M2H instruction books and the Doble Test Setups booklet.” to “Refer to the Doble M4000, instruction books and the Doble Test Setups booklet.” Section 5.7.1 - Changed “Do C1 and C2 tests on all bushings with capacitance or power factor taps.” to “Do C1 and C2 tests on all bushings with capacitance or power factor taps. If transformer is equipped with bushing pot devices, the C2 cord shall be removed from the bushing voltage tap prior to power factor testing. Do not test thru the C2 cord. The C2 voltage tap shall be cleaned, dried and inspected.” Section 5.8 - Changed “Perform the following if requested by Substation O&M Services. These tests …” to “Perform the following if requested by Substation Work Methods. These tests…” Section 5.9.2 - Changed “Note” to start on a new line. Section 5.9.3 - Changed “Set the Jofra 10 degrees below this temperature.” to “Set the Jofra 10° below this temperature.” Section 5.9.8 - Changed “Verify high oil temperature and high winding temperature alarms. High Oil alarm should be 100 degrees C; High winding temperature alarm should be 120 degrees C.” to “Verify high oil temperature and high winding temperature alarms. High Oil alarm should be 100°C; High winding temperature alarm should be 120°C.” Section 5.9.9 - Changed “When stabilized the gauge should agree with the temperatures set in the Jofra within plus or minus 7 degrees C.” to “When stabilized the gauge should agree with the temperatures set in the Jofra within ± 7°C.” Section 5.10.10 - Changed “… valve may open. If it lifts before4 1/25 psi or above …” to “… valve may open. If it lifts before 4 ½ psi or above …” Section 5.11.2.b - Changed “Refer to the National Grid Lead Compliance Plan for details when working with surfaces that may contain lead. (infonetus-Site Index-Safety and Occupational Health- Procedures_Policies)” to “Refer to the National Grid Lead Compliance Plan for details when working with surfaces that may contain lead. “ Section 5.11.3 - Changed “Utilize PeopleSoft ID# 5596056 paint for light grey applications and PeopleSoft ID# 5595920 paint for dark grey applications.” to “Utilize Strathmore Paint W80-0225 Base White (Dove Gray Color) or equivalent for transformer light grey applications and SAP # 9309442 paint for dark grey applications.” Section 5.14 - Changed “Perform surge arrester diagnostic inspection see SMP 419.01.3” to “Perform surge arrester diagnostic inspection see SMP 419.01.2” Section 5.15 - Changed “… diagnostic inspection, if equipped. See SMP 407.05.2” to “… diagnostic inspection, if equipped. See SMP 407.01.2” Section 5.16.2 - Changed “Use applicable Circuit breaker SMP and AIMMS PM.” to “Use applicable Circuit breaker SMP and CMMS Procedures.” Section 5.16.2.1 - Corrected format to make it 5.16.2.a Section 5.17 - Added Section 6.0 - Added and re-numbered accordingly Appendix A - Changed to “10.0 Appendix A …” Section 10.2.1 - Changed “… gauge S/C 5662850” to “… gauge S/C 9302812” Section 10.4.2 - Changed “… tester, MityVac P/N MV6212” to “… tester, such as a MityVac product (www.mityvac.com)” Section 10.4.3 - Changed “… Bleeder S/C 5660812.” to “… Bleeder S/C 9302741.” Note: SMP 402.02.3 Version 3.0 - Visual & Operational Inspection Section - Changed “(SMP 407.05.2)” to “(SMP 407.01.2)”; Diagnostic Inspection Section - Changed “Substation O&M

PRINTED COPIES ARE NOT DOCUMENT CONTROLLED. FOR THE LATEST AUTHORIZED VERSION PLEASE REFER TO THE APPROPRIATE DEPARTMENT WEBSITE OR DOCUMENTUM. File: SMP 402.02.2 TRANSFORMER 2.5 TO 14.9MVA Originating Department: Sponsor: Substation Work Methods Susan Fleck Massachusetts Electric Company Nantucket Electric Company Each d/b/a National Grid D.P.U. 18-150 Attachment AG-13-37-3 Page 19 of 20 SUBSTATION MAINTENENCE Doc. # SMP 402.02.2 Procedure Page 19 of 20 Transformer 2.5 to 14.9MVA (Base Rating) Version 3.0 – 05/28/13

Services” to “Substation Work Methods”, Changed “(SMP 407.05.2)” to “(SMP 407.01.2)”; Changed “Dew Point and % Oxygen” Table to “Additional Readings” Table and added a line

PRINTED COPIES ARE NOT DOCUMENT CONTROLLED. FOR THE LATEST AUTHORIZED VERSION PLEASE REFER TO THE APPROPRIATE DEPARTMENT WEBSITE OR DOCUMENTUM. File: SMP 402.02.2 TRANSFORMER 2.5 TO 14.9MVA Originating Department: Sponsor: Substation Work Methods Susan Fleck Massachusetts Electric Company Nantucket Electric Company Each d/b/a National Grid D.P.U. 18-150 Attachment AG-13-37-3 Page 20 of 20 SUBSTATION MAINTENENCE Doc. # SMP 402.02.2 Procedure Page 20 of 20 Transformer 2.5 to 14.9MVA (Base Rating) Version 3.0 – 05/28/13

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PRINTED COPIES ARE NOT DOCUMENT CONTROLLED. FOR THE LATEST AUTHORIZED VERSION PLEASE REFER TO THE APPROPRIATE DEPARTMENT WEBSITE OR DOCUMENTUM. File: SMP 402.02.2 TRANSFORMER 2.5 TO 14.9MVA Originating Department: Sponsor: Substation Work Methods Susan Fleck