Home    HVTM Division

HV AC Test Transformer

The AC test transformers are especially designed for testing high voltage products and components, such as cables, power transformers, gas-insulated switchgears, bushings and arresters. It is also suitable to test insulation materials. They are used to generate testing high voltage and function as part of the complete system. These systems are particularly suited for tests requiring stable voltage even if the load changes under voltage (corona, wet & pollution tests) or when the load is inductive (inductive voltage transformers).

The AC test transformer can be either in insulation cylinder type with metallic cover and base or metal tank. The insulation cylinder modular test transformers can be stacked to connect in series or parallel to get larger voltage or current to extend its application range.

Insulating sheath transformers is installed in an insulating sheath and is oil-cooled. Individual transformers can be connected in parallel or series to increase the current or the voltage. The possibility of stacking several of these transformer modules allows reaching very high voltage levels by keeping reasonable floor space.

Model No. Structure Max voltage
YDTW Single unit upto 750kV
YDTCW Cascaded upto 2250kV

Metal tank transformers is situated in an enclosed and earthed metal tank. This transformer is oil-cooled and can be optionally equipped with a suitable bushing (oil-to-air or oil-to-SF6). This design is allowing continuous operation and high currents (high power) which qualified for continuous duty, long duration tests.

Type Structure Max voltage
YDW Single unit upto 750kV
YDCW Cascaded upto 2250kV

AC Series Resonant Test System

Testing of certain apparatus requires much high voltage or current that a straight AC test system is not sufficient. Thus resonant test reactor with a variable core is needed. The main advantage of such test systems is lower input power and larger output power. The resonant test system is designed to compensate capacitance in the testing circuit precisely by tuning inductance of the test system. The natural resonance frequency of the test system matches feed-in mains, usually 50/60Hz. When the test system gets in resonance, it generates continuous testing high voltage.

AC resonant test system is used for factory testing of middle, high and ultra-high voltage cables, capacitors, generators, motors, power transformers and gas-insulated switchgears.

The resonant test systems can be either in insulation cylinder type or metal tank. Insulation cylinder reactors are in module and can be stacked to connect in series parallel to get much higher voltage or current. Additional voltage taps are possible for metal tank reactors. The output voltage is fed out through the tap-changers by HV bushings. This kind of reactors extend application range, and satisfy testing for cables of various voltage class.

Metal tank type HV Reactor is oil-cooled which is installed in a tank made of steel. The high voltage is fed outward through the steel tank via a HV bushing. The reactor can be fitted with additional voltage taps (bushings) to achieve largest testable capacitances of test objects at lower test voltages.

Model No. Structure Max voltage Max current
XZL Single unit upto 400kV 35A


Cylinder type HV Reactor is oil-cooled which is installed in a closed container made of steel and insulating cylinders. The module setup enables you to connect the reactors in series or in parallel for extending the range of voltage and/or current. The individual modules can be installed above or next to one another

Model No. Structure Max voltage Max current
XZL Single unit upto 400kV 35A
XZL Cascaded upto 2000kV 35A

Main components:

Additional features and accessories:

Gas-insulated AC Test System

The test system is used to do AC voltage withstand test and PD measurement for high voltage insulation products, combined electrical equipment, instrument transformers, etc.


Model No. YWDQ
Rated high voltage kV 250 300 500 550 600 750 1000
Rated low voltage kV 3/6
Rated capacitykVA 200/250/300/400/500/600
Rated short-time voltage withstand kV 275 330 550 600 660 825 1100
Rated frequency Hz 50
Partial discharge pC ≤3
Annual SF6 leakage ≤0.5%
Running time 15min at rated voltage, continuous running at 70% rated voltage
Weight kg 1800 2000 2500 2800 3000 3150 4500

Variable Frequency Resonant Test System

Variable frequency resonant system for testing of long HV cables and GIL, for testing of short HV cables and GIS/GIL and for testing of long MV cables are designed for the generation of alternating current (AC) high voltage (HV) by resonant circuits with variable frequency, available of outdoor design.





Main components:

HV reactors

Series XZF

insulating-case tank-type
up to 1600 kV up to 250 kV
up to 10 A up to 20 A
frequency 30-300 Hz frequency 30-300 Hz

Additional features and accessories:

Impulse Voltage Test System

CJDY Series Impulse voltage test systems are used for impulse voltage testing of transformers, cables, gas-insulated switchgears (GIS), arresters, and other high-voltage devices. The test systems generate lightning impulse voltage (LI, 1.2/50 µs), chopping lightning impulse voltages (LIC, front time 1.2 µs, front, crest or tail chopped), and switching impulse voltage (SI, 250/2500 µs) in accordance with IEC 60060-1; as well as IEC 60076-3 for transformers, and IEC 62067, 60840 und 60502-1 for cables).

Impulse voltage test systems are available for factory testing in three product lines (E, V, and H).

E type V type H type
up to:1800 kV up to:4800 kV up to:7200 kV
up to:180 kJ up to:600 kJ up to:1620 kJ


To generate impulse voltages for testing:

Main components:

Special components for impulse voltage test systems:

Impulse Current Test System

Impulse Current Test Systems are manufactured for testing equipment applied in medium and high voltage transmission & distribution systems against the effects of lightning strokes (direct or indirect) or against electromagnetic interference effects





Main components:

High Voltage DC Test System

DC test systems are used to test components and complete systems found in electrical power supply systems and operating on DC voltage. POWERHV DC voltage test systems fulfill the requirements of IEC 60060-1.

The DC voltage test systems can be equipped with polarity reversal.





Main components:

Control system (manual operation or computer-aided automatic systems)

Additional features and accessories: