Related Manuals for ABB UC Series
Summary of Contents for ABB UC Series
- Page 1 1ZSE 5492-129 en, Rev. 6 On-load tap-changer, type UC with motor-drive mechanisms, type BUE/BUL Repair guide...
- 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 Recommended practices ABB recommends careful consideration of the following factors for service and repair work on on-load tap-changers. Do not repair an on-load tap-changer or motor-drive mechanism with a serious mechanical or electrical fault without first consulting ABB. Before you start any work, make sure that the personnel doing the job have read and fully understood the Repair documents provided with the unit.
- Page 4 CAUTION ABB recommends that only service engineers with appropriate skills regarding on-load tap- changers carry out the repairs. ABB recommends that only maintenance engineers trained by ABB carry out contact re- placement. During service WARNING Small amounts of explosive gases will always come out from the breathing devices (dehydrating breather or one-way breather).
- Page 5 WARNING When oil that has been used in a diverter switch compartment is pumped out, con- ducting tubes and hoses that are earthed should be used to avoid the risk of explo- sion due to the gases produced by the arcs during service. The oil in the diverter switch compartment may be hot.
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Page 7: Table Of Contents
Contents 1. Introduction _______________________________________________________9 1.1 General _______________________________________________________9 1.2 Repair categories _______________________________________________9 1.3 Serial number __________________________________________________11 1.4 Spare parts list _________________________________________________11 1.5 Maintenance guide ______________________________________________12 1.6 Tightening torque _______________________________________________12 2. Trouble-shooting ___________________________________________________13 2.1 On-load tap-changer ____________________________________________13 2.2 Pressure relay __________________________________________________14 2.3 Motor-drive mechanism __________________________________________15 2.3.1 Control system _____________________________________________15 2.3.2 Power system ______________________________________________17 2.3.3 Miscellaneous ______________________________________________17... -
Page 9: Introduction
1. Introduction 1.1 General The UC range of on-load tap-changers manufactured by ABB has been developed over many years to provide maximum of reliability. The simple and rugged design gives a service life equal to the service life of the transformer. Minimum maintenance is required for trouble- free operation. - Page 10 1. Introduction Diverter switch housing Cover Oil valve Pressure relay Bevel gear Position indicator Top-section Serial No. Shielding-ring Earthing terminal Draining tube Connection flange for gas operated relay Insulating cylinder Insulating shaft Diverter switch Shielding-ring Shielding-ring Plug-in contacts Transition resistors Fixed and moving contacts Bottom section...
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Page 11: Serial Number
1. Introduction 1.3 Serial number Before consulting ABB for technical advice to assist with repairs or to order spare parts to complete the repairs, the on-load tap-changer serial number must be known. The serial number can be found on the following locations: ■... -
Page 12: Maintenance Guide
1. Introduction 1.5 Maintenance guide Inspection and overhaul of the UC range of on-load tap-changers are carried out accord- ing to the instructions in the appropriate 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:... -
Page 13: Trouble-Shooting
2. Trouble-shooting 2. Trouble-shooting This chapter mainly contains information used to locate a fault. Instructions for correcting the fault, replacement of parts etc. are contained in chapter 3 Repairs and Adjustments. 2.1 On-load tap-changer Error condition Fault finding procedure High oil level alarm. A rising oil level in the on-load tap-changer oil con- servator may indicate a leakage between the diverter switch housing and the transformer tank. -
Page 14: Pressure Relay
2. Trouble-shooting 2.2 Pressure relay WARNING To take the transformer into service after a pressure relay trip without carrying out a careful investigation of the diverter switch by lifting it out of the diverter switch hous- ing, and repairing faults, if any, may cause severe damages to the on-load tap-chang- er and the transformer. -
Page 15: Motor-Drive Mechanism
2. Trouble-shooting 2.3 Motor-drive mechanism 2.3.1 Control system Error condition Fault finding procedure LOCAL operation or 1. LOCAL operation is not possible when the control REMOTE operation is not selector switch is in position REMOTE or 0, and possible. REMOTE operation is not possible in position LOCAL or 0. - Page 16 2. Trouble-shooting Error condition Fault finding procedure The remote position indicator 1. If there is a measuring amplifier: shows wrong position or there is no signal Adjust the output signal from the measuring ampli- fier with its two adjustment screws. If the failure does not disappear, proceed as follows: WARNING Dangerous supply voltage!
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Page 17: Power System
2. Trouble-shooting 2.3.2 Power system Error condition Fault finding procedur The three-phase motor runs Reverse two of the phases of the incoming supply. back and forth without the on-load tap-changer changes WARNING position. Dangerous voltage! 2.3.3 Miscellaneous Error condition Fault finding procedure Corrosion and/or condensa- 1. - Page 18 2. Trouble-shooting fm_00236 Fig. 4. Standard circuit diagram BUE. For actual information use the circuit diagram delivered with your on-load tap-changer. 1ZSE 5492-129 en, Rev. 6...
- Page 19 2. Trouble-shooting fm_00237 Fig. 5. Contact timing diagram BUE. 1ZSE 5492-129 en, Rev. 6...
- Page 20 2. Trouble-shooting fm_00238 Fig. 6. Standard circuit diagram BUL. For actual information use the circuit diagram delivered with your on-load tap-changer. 1ZSE 5492-129 en, Rev. 6...
- Page 21 2. Trouble-shooting fm_00239 Fig. 7. Contact timing diagram BUL. 1ZSE 5492-129 en, Rev. 6...
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Page 22: Repairs And Adjustments
3. Repairs and adjustment 3. Repairs and adjustments 3.1 Replacement of gear box on the on-load tap-changer or replacement of o-rings for the gear 3.1.1 General This instruction guides you on how to replace the gear box on the top section of the UCG, UCL and UCC, UCD on-load tap-changers. -
Page 23: Procedure
3. Repairs and adjustment 3.1.4 Procedure WARNING Before any work is carried out on the on-load tap-changer: Make sure that the transformer is disconnected and that earthing is properly carried out. Obtain a signed certificate from the engineer in charge. The oil in the diverter switch housing may be hot. - Page 24 Max permitted deviation is shown in Fig. 8. Also check that all units 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.
- Page 25 3. Repairs and adjustment CAUTION Make sure that no loose parts fall into the transformer through the hole for the gear box. No driving shaft of the on-load tap-changer is allowed to be rotated. 10. Remove the cover of the new gear box. 11.
- Page 26 3. Repairs and adjustment 21. Check that the position indicator in the second gear box is in its exact position, see Fig. 8. If not, loosen the two screws in the multihole coupling on the second gearbox and find the position of the screws that positions the opening in the brass toothed wheel closest to the red point in the gear box housing.
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Page 27: Replacement Of Diverter Switch Housing Cover Gasket
3. Repairs and adjustment 3.2 Replacement of diverter switch housing cover gasket 3.2.1 General This instruction guides you how to attend to an oil leakage. The instruction can be used for all UC-types of on-load tap-changers. 3.2.2 Tools required ■ Box wrench (19 mm) 3.2.3 Material and spare parts required ■... -
Page 28: Restoring The Gas Cushion
The procedure below is used for on-load tap-changers without oil filter unit for continuous oil filtration. In case the on-load tap-changer is equipped with an oil filter unit for continuous oil filtration from ABB, and it is installed according to our recommendations, follow the instruc- tions in the for restoring the gas cushion. - Page 29 3. Repairs and adjustment Open the valve in the tube to the conservator! 10. Pump the earlier drained oil back into the diverter switch housing. 11. Close the oil valve and disconnect 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.
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Page 30: Replacement Or Addition Of A Multi-Position Switch (Bul Only)
3.4.1 General Addition of a multi-position switch as described below is possible when you have 1, 2, or 4 multi-position switches. In other cases the shaft must also be exchanged and ABB should be contacted for further instructions. 3.4.2 Tools Required ■... - Page 31 3. Repairs and adjustments Upper coupling half Torque disc Lower coupling half Shaft Transparent cover Multi-position switch Contact arm Distance screw L = 20 mm Distance screw L = 10 mm or 35 mm Bottom place Sliding bearing Fig. 10. Multi-position switch for BUL. 1ZSE 5492-129 en, Rev.
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Page 32: Examination Of The Diverter Switch After A Pressure Relay Trip
3. Repairs and adjustments 3.5 Examination of the diverter switch after a pressure relay trip The pressure relay has tripped during normal operation. 3.5.1 Tools and material required ■ Maintenance guide for the on-load tap-changer in question ■ Lifting device as proposed in Maintenance guide ■... -
Page 33: Tests Of The Pressure Relay
3. Repairs and adjustments 3.6 Tests of the pressure relay Tools required: ■ Air pump with pressure gauge (0-250 kPa) and connection to R 1/8” male thread. ■ Screwdriver ■ Megger (500-2 000 V) 1. Insulation test Remove the cover of the relay housing. Disconnect all incoming wires from the terminals. Connect terminal NO (identified 61) on the pressure relay block to earth. -
Page 34: Replacement Of Pressure Relay
3. Repairs and adjustment 3.7 Replacement of pressure relay 3.7.1 General If the pressure relay fails to pass the insulation test and/or the function test, the pressure relay has to be replaced. CAUTION It is not permissible to replace only the microswitch inside the pressure relay. 3.7.2 Tools required ■... - Page 35 3. Repairs and adjustments Information plate Pressure relay Valve handle Connection nut Quick coupling Test tap (R 1/8’’) TC_00264 Three way valve handle Fig. 11. Pressure relay. 1ZSE 5492-129 en, Rev. 6...
- Page 36 Contact us ABB AB Components 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...