Requirements of a system for the artificial ageing of paper insulated lead covered medium voltage cables

A higher percentage of the electrical distribution grid in Germany is still working with the elderly paper insulated lead covered (PILC) cables. For a cost-efficient asset-management of electrical grids, the status and remaining lifetime of electrical equipment is of highest interest. Diagnostic systems on the market do not deliver a significant and detailed information about the ageing status. Due to this fact, a longer lasting project is set up with the goal to artificially age, analyse and diagnose the ageing behaviour of PILC MV-cables. The general task of the accelerated ageing system is to apply enforced stress conditions to selected test cables out of field operation. In this way, defined artificial and accelerated ageing conditions are generated to provoke faster but realistic ageing processes. The characteristic diagnostic values are regularly acquired by a specific automatized measurement and control system together with necessary additional data, like e.g. temperatures, applied voltages and currents, which are controlled by sensors. In the article the methods, the design and the key values for the projection of the system will be presented. Using this approach, it is possible to simulate the ageing of field equipment during its operation over several decades within an experimental time span of several months.