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The UC family is a group of diverter switch on-load tap-changers. They come in a wide range of models with a rating suitable for every application. They are mounted inside of the transformer tank, suspended from the transformer cover. The UC types operate with conventional arc quenching in oil diverter switches.

The UCD model is the largest of the UC types and is capable of meeting the most demanding requirements with a BIL rating of 1050 kV and current rating of 1600 A.

Extend your transformer’s lifetime and easily upgrade to on-load tap-changers type UCD with vacuum technology.

Product scope

  • Base technology: Conventional, resistance, in-tank
  • Common applications: Network, special, industrial, HVDC
  Tap-changer placed in the neutral point of the winding Other placements of the tap-changer
Highest voltage for equipment (Um)  300 kV 300 kV
Max lightning impulse (BIL) 1050 kV 1050 kV
Max current
1-phase (one tap-changer/phase)
1000 A
1600 A
1600 A
1600 A
Max step voltage 5000 V 5000 V


Why Hitachi Energy?

  • Unique open design for quick and easy maintenance
  • Maintenance in any tap position and without dismantling the shaft system, thus eliminating the risk for failure from improper assembly or alignment
  • No online oil filter is needed
  • Unsurpassed maintenance intervals
On-load tap-changers type UCD

Get to know more

Document title ID
Technical guide 1ZSC000562-AAW
Declaration of conformity 1ZSC000498-ABN
Ordering data form (.xlsm)
Please note that this is an interactive form, which can be filled in, saved and sent to us by e-mail.
Ordering data form explanations 1ZSC000498-AAP
User's manual 1ZSE 5492-155
Installation and commissioning guide UCC/UCD 1ZSE 5492-117
Maintenance guide UCC/UCD 1ZSE 5492-126
Repair guide 1ZSE 5492-129
Spare parts list 1ZSC000562-ACX
Accessories and protection devices 1ZSC000562-AAD
Oil filter unit, type HPS 27/27, 54 1ZSC000562-AAF
Oil filter unit, type OLU 1ZSC000562-AAR

Insulating level (kV) Switching type Connection Rated current (A) Number of positions Drawing number
L N 1000 5-18 5492 0091-1
E 1000 5492 0091-2
1200 5492 0091-3
R, D N 1000 9, 13 5492 0091-5
11, 15-35 5492 0091-6
E 1000 9, 13 5492 0091-7
11, 15-35 5492 0091-8
1200 9, 13 5492 0091-9
11, 15-5 5492 0091-10

The drawing shows Drawing number
External drive shaft system 5492 0083-4
Mounting on active part 5492 0087-1
Standard top section without oil filter unit 5492 0087-2
Top section for oil filter unit 5492 0087-3
Top section with two valves R1" 5492 0087-4
Drain valve 5492 0083-10
Pressure relief device - flow diameter 130 mm - Qualitrol 5492 0083-15
Pressure relief device - flow diameter 50 mm, standard - Comem 1ZSC003721-AAW
Pressure relief device - flow diameter 50 mm, class C5-M - Comem 1ZSC003721-AAV
Bevel gear (on top section, T-shape) 5492 0083-19
Bevel gear (on top section, L-shape) 1ZSC004021-AAD
Bevel gear (in external drive shaft system) 5492 0083-1
Support for bevel gear (on external drive shaft system) 5492 999-11
Pressure relay 5492 0083-2
Oil flow relay 1ZSC003527-ABB
Temperature relay 1ZSC003716-AAM
Temperature sensor 1ZSC005333-AAF
Temperature sensor and pressure relay 5492 0083-34
Thermo switch housing 5492 0083-22

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