The partial discharge measurement is a very well known possibility to assess the quality of an insulation system. The aim is the detection of destruction in the electrical insulation as a result of electrical stress. In the working field of technical diagnostics, alternatives to the conventional partial discharge (PD) measuring techniques, with the aim of evaluating the insulation condition of electrical equipment are looked for. In a research project, a contribution in the area of optical partial discharge measurement technique and analysis was compiled. An optical partial discharge measuring system was developed, which gives the basis for investigations inside electrical equipment.