An exemplary test arrangement for in-situ partial discharge measurements in distribution transformers has at least one test system with a plurality of test components including: an AC voltage source for producing a variable test voltage with a measuring apparatus for recording current pulses caused by partial discharge and with an evaluation apparatus for the recorded current pulses, a grounded test container in which at least some of the test components are arranged, and a distribution transformer connected to the AC voltage source as a test object. The test object is arranged on insulation means for electrically insulating the test object. Those parts of the test object which are grounded during normal operation being connected at least to the potential of the grounded test container.