Fundamental Study for Correction Technique in Space Charge Measurements of Cables under Load-cycle Using Pulsed Electro-Acoustic Method

This paper discusses a correction technique for space charge measurements in cables under load cycling using the pulsed electro-acoustic (PEA) method. In general, the functions, such as the system impulse response, required to convert measured waveforms into charge distributions are extracted under the same thermal conditions as the measured waveforms. However, it is not feasible to obtain the system impulse response for all transient temperature conditions under a load cycle temperature condition where the temperature changes from time to time. Therefore, we proposed the method of using the impulse response measured at different temperatures for the conversion. It was found that the root mean square error in the electric field distribution was up to about 3.4% with respect to the average electric field by using our proposed method. This result supports the conclusion that the method proposed in this paper is applicable to the conversion of waveforms into charge distributions under load cycle temperature conditions.