Evaluation of Thermally Aged Nuclear Power Plant Power Cables Based on Electrical Condition Monitoring and Regression Analysis

Abstract

The safe operation of nuclear power plants relies on many components such as nuclear reactors, heat exchangers, concrete structure and thousands of kilometers of instrumentation, control and low voltage power cables. The severe operating conditions in the nuclear power plants which characterized by high radiation levels and elevated temperature affect the insulation integrity of these cables, therefore, the condition monitoring of these cables has a particular concern. In this research, low voltage nuclear power plant power cables were thermally accelerated aged for different aging periods to simulate different service periods. The effect of the thermal aging on these cables was investigated using the extended voltage response method where two parameters were measured, the slope of decay and return voltages. The results showed that the voltage decay slope increased with increasing the aging period while the return voltage slope decreased. The estimated values of the return voltage slope were calculated using the parameters obtained from the regression analysis and this showed a strong correlation with the aging and polarization processes.