Testing, Measuring and Diagnosis

Abstract

High-voltage test and measuring techniques and technologies for diagnostics and monitoring of high voltage insulating systems are essential for the proof of operational safety of equipment and systems prior to commissioning and during service operation, because small defects can develop into serious consequences. The starting point of the considerations is the system of quality assurance and insulation coordination, for which the voltage stresses in the net, the protection elements and the dielectric strengths of the insulation or test voltage levels are coordinated. The generation of high test voltages is performed by special equipment for AC, DC and impulse voltages that can often be cascaded. The measurement of high voltages is normally based on special voltage dividers, but alternative systems (measurement spark gaps, field sensors, instrument transformers) are also used. Additionally, the technologies for current measurement and for undisturbed measurements (EMV) must be considered. During a voltage test and during service operation, electrical, dielectric, chemical and physical methods are used for diagnostic purposes, in order to assess the condition of equipment.