High-Power Testing Laboratory

In the high-power testing laboratory circuit breakers and other medium voltage components will be tested for short-circuit making and breaking capacity, capacitive switching capacity, short-time and peak-withstand current and various other tests. A nominal short-circuit current of up to 40 kA at 19 kV can be generated during tests. The power can be adapted to the respective requirements using power transformers and reactors.

We test for you!

Just contact us.


Testing portfolio

- Short-circuit tests for making and breaking capacity of circuit breakers

- Capacitive switching capacity tests

- Short-time and peak-withstand current tests for determination of dynamic and thermal stress

- Load current switching tests
- Motor current switching tests

- Electrical endurance tests for short-circuit currents

- Making capacity tests for earthing switches

- Breaking capacity for normal currents performed as endurance test

Our testing laboratory at a glance:


Performance data of the high-power testing laboratory


  • Maximum generator output                                                                                1300 MVA
  • Maximum short-circuit current (single and three phase[peak/rms])             105/40 kA
  • Maximum short time withstand current, 3 s (says 4s below)                         72 kA
  • Frequency                                                                                                               50/60 Hz

Overview ov the technical equipment

Short-circuit generator

Technical data of short-circuit generator


  • Nominal voltage (star/delta)                                           19 / 11 kV
  • Maximum operating voltage                                           21 kV
  • Nominal power                                                                  64 MVA
  • Nominal speed                                                                   3000 / 3600 U/min
  • Operating frequency                                                         50 / 60 Hz
  • Maximum short-circuit current                                        40 kA at 19 kV
  • Weight of stator                                                                 160 t
  • Weight of rotor                                                                   38 t
  • Overall weight                                                                    210 t

The heart of the high-power testing laboratory is the formed? by a short circuit generator supplied by Siemens generator plant. The power of 1300 MVA corresponds to a maximum short-circuit current of 40 kA at a source voltage of 19 kV.

A 1.5 MW asynchronous machine fed (controlled?) by a frequency converter operates as the drive engine. The starting time is roughly 10 minutes. Braking to complete stop takes about 40 minutes.

Short-circuit transformer

Electrical characteristics of the transformers


  • Manufacturer                                                                         Siemens
  • No. of single-phase units                                                     3
  • Nominal design rating of one unit                                     120 MVA
  • Nominal voltages                                                                  35/70/140 kV
  • Low voltage                                                                           max. 19 kV
  • High voltage, single-phase                                                  max. 420 kV
  • Nominal frequency                                                               50 Hz
  • Max. permissible primary short-circuit current                40 kA
  • Max. permissible peak short-circuit current                     68 kA
  • Weight per unit (filled with oil)                                          120 t

The transformers are of six-leg type, each of the four central legs being equipped with a 35 kV coil on the high-voltage (HV) side. The two outer legs are unwound and form the return path for the magnetic flux. The four coils can be connected in any combination. Metal-oxide arresters are used to protect the windings against switching over voltages that can appear between phase and ground and phase-to-phase.


We will test your equipment!

Contact us to discuss and arrange your individual tests.

Take advantage of our services

Here you will find important information and documents relating to our testing laboratories at Schaltwerk Berlin.