ABB BUE, Repair Manual

Page 1: ...On load tap changer type UC with motor drive mechanisms type BUE BUL Repair guide 1ZSE 5492 129 en Rev 6 ...

Page 2: ...This document must not be copied without our written permission and the contents thereof must not be imparted to a third party nor be used for any unauthorized purpose Contravention will be prosecuted ...

Page 3: ...TE provides additional information to assist in carrying out the work de scribed Safety precautions WARNING Before any work is carried out on the on load tap changer Make sure that the trans former is disconnected and that earthing is properly carried out Obtain a signed certificate from the engineer in charge The relevant technical documents should be read and understood before any work is starte...

Page 4: ...pressure relay trip follow the instructions in the chapter Pressure relay in this guide During oil handling WARNING Unused transformer oil is slightly harmful Fumes from unused warm oil may irritate the respiratory organs and the eyes After long and repeated contact with transformer oil skin becomes very dry Used on load tap changer oil from diverter switch housings and selector switch housings co...

Page 5: ...h housing Take care to avoid ingestion of moist air when oil is drained If the ambient air is moist let incoming air pass through a dehydrating breather with slow air flow to obtain proper dehy dration NOTE Check the oil level one month after filling It is usual for the oil level of the oil conservator to fall due to gas absorption in the oil from the gas cushion in the diverter switch housing if ...

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Page 7: ... Procedure__________________________________________________23 3 2 Replacement of diverter switch housing cover gasket_ ________________27 3 2 1 General____________________________________________________27 3 2 2 Tools required_______________________________________________27 3 2 3 Material and spare parts required_ ______________________________27 3 2 4 Procedure__________________________________...

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Page 9: ...d tap changers type UC are housed in the transformer tank The motor drive mechanisms types BUE or BUL are attached to the transformer tank and connected to the on load tap changer by means of drive shafts and a bevel gear see Figs 1 and 2 1 2 Repair categories Repairs on the UC range of on load tap changers fall into two categories Repairs Repairs are to replace worn or end of service life parts M...

Page 10: ... contacts Intermediate gear Insulating shaft Bevel gear Position indicator Fig 1 General arrangement of on load tap changer type UC Earthing terminal Serial No Diverter switch housing Serial No Connection flange for gas operated relay Shielding ring 2 Shielding ring 1 1 Only at impulse withstand voltage to earth of 650 kV and 1050 kV 2 Not on UCG of the short type Tap selector Fixed fine selector ...

Page 11: ...if the transformer is manufactured by ABB in Ludvika Sweden NOTE One of these serial numbers must be quoted in all correspondence and telefax messages and during any telephone conversations with ABB Failure to use the serial number may cause delays Serial No BUL FM_00006 FM_00200 BUE 1 4 Spare parts list The Repair guide does not contain information about spare parts and how to order them For info...

Page 12: ...ppropriate Maintenance guide You will need the Maintenance guide since references are made to it 1 6 Tightening torque The following tightening torques are recommended for metallic screw joints M6 10 Nm 10 M8 24 5 Nm 10 M10 49 Nm 10 M12 84 Nm 10 for non metallic screw joints M10 9 Nm 10 M12 13 Nm 10 M16 22 Nm 10 if not otherwise is stated in this guide 1 Introduction ...

Page 13: ...y indicate a leakage between the diverter switch housing and the transformer tank Make sure that the cause for the alarm is not over filling at commissioning or overhaul This can be checked by adjusting the oil level according to the transformer documentation and then rechecking some time later Low oil level in the oil conser vator 1 Check for leakages 2 If no leakages are found the gas cushion is...

Page 14: ...or condition Fault finding procedure The pressure relay has tripped during normal operation 1 Examine the diverter switch according to section 3 5 Examination of the diverter switch after a pres sure relay trip in this guide Continue with steps 2 and 3 if no fault is found 2 Carry out tests on the pressure relay according to section 3 7 Tests of the pressure relay in this guide 3 The on load tap c...

Page 15: ...ective motor switch 6 If the motor drive has been handcranked against the mechanical endstop handcrank back to end position The on load tap changer performs more steps than ordered or operates to wards the end stop 1 Check that the maintaining contact releases after operation WARNING Dangerous voltage 2 Check that the raise and lower contactors function properly see circuit diagram Fig 4 respectiv...

Page 16: ... reaches the position indica tor 2 Measure the resistance on the terminals of the position transmitter in all positions after both raise and lower operations WARNING Before starting any work inside the motor drive mechanism the auxiliary power must be switched off N B The motor contactors and heating element may be energized from separate sources BUE 3 Check that the contact plate and arm on the m...

Page 17: ...e incoming supply WARNING Dangerous voltage 2 3 3 Miscellaneous Error condition Fault finding procedure Corrosion and or condensa tion in the motor drive mecha nism cabinet 1 Check the function of the heater Refer to section Heater in the Maintenance guide 2 Check that the air vents not have been blocked Water in the motor drive mechanism cabinet 1 Adjust the hinges on the cabinet door 2 Replace t...

Page 18: ...ded when the on load tap changer has through positions Closed when the on load tap changer is in through positions fm_00236 Fig 4 Standard circuit diagram BUE For actual information use the circuit diagram delivered with your on load tap changer 2 Trouble shooting ...

Page 19: ...19 1ZSE 5492 129 en Rev 6 fm_00237 Fig 5 Contact timing diagram BUE 2 Trouble shooting ...

Page 20: ...ded when the on load tap changer has through positions Closed when the on load tap changer is in through positions fm_00238 Fig 6 Standard circuit diagram BUL For actual information use the circuit diagram delivered with your on load tap changer 2 Trouble shooting ...

Page 21: ...21 1ZSE 5492 129 en Rev 6 Fig 7 Contact timing diagram BUL fm_00239 2 Trouble shooting ...

Page 22: ...e cautious CAUTION When making this repair it is important that neither the on load tap changer nor the motor drive mechanism is operated with the shafts disconnected 3 1 2 Tools required Normal set of handtools Socket wrench with extension socket for 8 mm Allen screw Sliding caliper Graduated limb 3 1 3 Material and spare parts required Gear box O ring 84 1 x 5 7 for UCL O ring 92 5 x 5 7 for UCG...

Page 23: ... a signed certificate from the engineer in charge The oil in the diverter switch housing may be hot Be cautious Clamps washers and screws TC_00151 Fig 8c Tap changer from above Position indicator Bolts and tightening washers Red point Exact position Tolerances Position indicator Fig 8b Gear box UCG UCC UCD Fig 8a Gear box UCL Position indicator Locking device TC_00257 TC_00156 3 Repairs and adjust...

Page 24: ...s are in the same service position as the motor drive If something is out of range please consult ABB for advisory CAUTION To take an on load tap changer that is not aligned and or out of position into service means a great risk for damaging both the on load tap changer and the transformer It is very important that the following instructions are followed in detail to make sure that the on load tap...

Page 25: ...the fixed brass coupling to the gear box closest to the motor drive Put on the protection tubes and hose clamps 18 Fit the loosened coupling to the replaced gear box Tighten the two screws closest to the gear box first leaving an axial play of 2 mm Tighten the remaining screws Check that the position indicator in the gear box is in its exact position see Fig 8 If not loosen the two screws in the m...

Page 26: ... all gear boxes are lubricated with grease If not apply grease on the gears 24 Make a final check that all gear boxes are in their exact positions within the tolerance given in Fig 8 and that all on load tap changer units are in the same service position as the motor drive 25 Mount the gaskets and covers of the gear boxes On UCL there is a slot in the cover for a gear Make sure the cover is turned...

Page 27: ...erter switch housing No open fire hot surfaces or sparks may be present during opening of the housing or draining from the valve After the cover is removed let the gas vent away approxi mately 15 min before any work is started CAUTION Protect the on load tap changer from water 1 Retighten the nuts that hold the cover If the oil leakage still remains the O ring has to be replaced 2 Shut the valve t...

Page 28: ...n load tap changer for connection dimensions of the oil valve 3 3 3 Procedure WARNING The oil in the diverter switch housing may be hot Be cautious There is always a cushion of explosive gases in the top of the diverter switch housing No open fire hot surfaces or sparks may be present during opening of the housing or draining from the valve After the cover is removed let the gas vent away approxi ...

Page 29: ...t the pump 12 The level in the oil conservator and the gas cushion are now restored CAUTION Avoid to do the restoring in damp weather since moisture will get into the diverter switch housing If the restoring has to be done in such weather the incoming air has to be dehy drated and the drained oil protected from water Open TC_00171 Air release valve 3 Repairs and adjustment Fig 9 ...

Page 30: ...ce screws to new ones length 20 and 10 or 35 mm 3 Turn the contact arm on the new multi position switch to the same position as the exist ing multi position switches Place the transparent cover on the multi position switch and push it all on the shaft The nob in the hub of the multi position switch must enter the groove in the shaft 4 Reassemble washers and distance screws Press up the shaft and m...

Page 31: ...adjustments Distance screw L 20 mm Distance screw L 10 mm or 35 mm Multi position switch Transparent cover Shaft Upper coupling half Bottom place Sliding bearing Torque disc Lower coupling half Contact arm Fig 10 Multi position switch for BUL ...

Page 32: ...re relay trip Follow the procedure in section Lifting and cleaning the diverter switch in the Mainte nance guide when lifting the diverter switch Look for flash marks loose parts etc Measure the transition resistors according to section Checking the transition resistors in the Maintenance guide Finish with an even number of operations of the diverter switch according to section Checking the contac...

Page 33: ...d reconnect the incoming wires If the pressure relay does not withstand the electrical stress the pressure relay should be replaced see section 3 9 Replacement of pressure relay 2 Function test Set the valve handle to the test position as shown on the information plate Connect the air pump and the pressure gauge to the test tap on the pressure relay Thread R 1 8 Raise the pressure until the pressu...

Page 34: ...lacement of pressure relay 1 Set the three way valve handle to the test position see Fig 11 and the information plate on the pressure relay WARNING Disconnect all power sources before any work is carried out Check that the power is disconnected by using a Voltmeter 2 Disconnect the cable 3 Loosen the quick coupling and remove the pressure relay 4 Install a new O ring 17 1x1 6 mm 5 Lubricate the th...

Page 35: ...35 1ZSE 5492 129 en Rev 6 3 Repairs and adjustments Fig 11 Pressure relay Information plate Valve handle Test tap R 1 8 TC_00264 Three way valve handle Quick coupling Pressure relay Connection nut ...

Page 36: ...onents SE 771 80 Ludvika Sweden Phone 46 240 78 20 00 Fax 46 240 121 57 E Mail sales se abb com www abb com electricalcomponents Contact us Copyright 2011 ABB All rights reserved 1ZSE 5492 129 en Rev 6 1999 11 30 ...