Methods for partial discharge testing of aerospace cables

The aerospace industry has moved towards more advanced electrical systems in order to replace heavier mechanical and pneumatic systems to reduce the aircraft weight. The resulting increase in electrical power demand could have been achieved by increasing the current or the voltage. The disadvantage of increasing the current is that heavier conductors are required. Efforts have therefore focused on increasing the supply voltage. The move to higher voltages comes with an increased risk of partial discharges (PD). This risk must be managed in an environment where systems must remain as compact and as light as possible. This paper focuses on experimental testing that has been used to investigate the suitability of a variety of methods for the PD testing of cables, operating under AC high voltage stresses in an aerospace environment. A number of cable samples of the same type have been tested in different configurations in an effort to replicate different aircraft cable harnesses. These configurations were compared with the currently used cable configuration as found in BS EN 3475-307, to check the consistency of PD results and if the discharge mechanisms involved in each configuration differ. Results have shown a variation in the PD mechanisms. In addition the different types of PD and the configuration methods are discussed in relation to the aircraft cable harness.