Partial discharge detection techniques are provided. In one aspect, a method of detecting partial discharge in an electrical power system having a power electronics converter is provided. A first current signal is captured in response to a first applied voltage. A second current signal is captured in response to a second applied voltage, the second applied voltage being different than the first applied voltage. The first current signal is set as a reference signal. A difference signal is determined based on the second current signal and the reference signal. A determination is made as to whether partial discharge is present based on the difference signal. The method may iterate, and for each iteration, the reference signal is refreshed on a rolling basis as a previously captured current signal measured in response to a previously applied voltage. The applied voltage is also stepped up or down for each iteration.