ABSTRACT
This chapter presents some of the techniques and theory involved in the testing of high-voltage equipment either in the laboratory or in the field. The main concern with electric equipment is that its insulation should withstand its operating voltage and the occasional overvoltage transients expected in the system. High-voltage dielectric loss and partial discharge testing can, to some extent, help in the selection and design of insulation for electrical equipment. The conventional forms of test voltages in use can be divided into three main groups: direct voltages, power-frequency alternating voltages, and impulse voltages, which are divided into lightning and switching impulses. Direct voltage is used mainly to test equipment used in high-voltage DC transmission systems. It is additionally used in insulation testing of arrangements with high capacitance, such as capacitors and cables. Testing of circuit breakers requires highly equipped laboratories and sophisticated testing procedures.
