SZ20 on-load tap-changing transformers, 35 kV class

Oil-immersed transformers with an on-load tap-changer, for 35 kV networks. An 8 000 kVA, 35/10.5 kV unit passed type tests to GB standards in August 2025.

Tap-changer: On-load
Voltage class: 35 kV
Tested unit: 8 000 kVA, 35/10.5 kV

A large oil-immersed transformer seen from the front, with radiator banks, a conservator and an on-load tap-changer compartment — A large oil-immersed transformer with an on-load tap-changer compartment, in the factory.

Tested unit

SZ20, 8 000 kVA

SZ20-8000/35, oil-immersed power transformer with on-load tap-changer, 8 000 kVA, 35/10.5 kV. Tested 13 July to 12 August 2025; issued 12 August 2025.

Rated power: 8 000 kVA
Voltage: 35/10.5 kV
Type: Oil-immersed power transformer with on-load tap-changer

Lab: Anhui Product Quality Supervision & Inspection Research Institute
Standards: GB/T 1094.1, .2, .3, .5 and .10With GB/T 6451-2023, GB/T 7595-2017 and JB/T 501-2021
Result: PassedType test, including measurements before and after the short-circuit withstand test

[TBC: measured losses for the SZ20]

Documents

Report (2025) 皖检JZ字第0594号

Ask for the full report

All tests, standards and filing for SZ20

Unit: SZ20-8000/35, oil-immersed power transformer with on-load tap-changer, 8 000 kVA, 35/10.5 kV
Tests: Type test, including measurements before and after the short-circuit withstand test
Standards: GB/T 1094.1, GB/T 1094.2, GB/T 1094.3, GB/T 1094.5, GB/T 1094.10, GB/T 6451-2023, GB/T 7595-2017, JB/T 501-2021

Other ratings and voltages

Our range goes up to 35 kV and 31 500 kVA. [TBC: kVA ratings and tap ranges offered in the SZ20, measured losses, and whether it is also designed and tested to IEC 60076]

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What to send for a quote

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Rated power (kVA) and quantity
Primary and secondary voltage, and the tapping range
Frequency: 50 or 60 Hz
Vector group, for example Dyn11
Cooling, and indoor or outdoor installation
The standard your project specifies
Destination port or site, and the delivery date you need

SZ20

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