I-V Lissajous Pattern: a Promising Condition Monitoring Technique for High Voltage Assets

The current-voltage (I-V) characteristics of critical high voltage assets such as power transformers, overhead transmission lines and underground cables are affected by various factors including the asset’s health state along with other operating and environmental conditions. Understanding the current-voltage characteristics of such assets is essential for reliable and efficient operation of power transmission and distribution networks. The measurement of such parameters does not call for additional hardware as it utilises easily accessible voltage and current data at both terminals of the asset. The I-V characteristic can be considered as a unique fingerprint for the asset during its normal operation. variations in the fingerprint can be easily detected using a proper software code. The variation can be observed in real time and analysed using digital image processing and artificial intelligence-based techniques to identify and quantify any abnormal event or a fault at early stage. This paper discusses the potential of using the I-V Lissajous pattern to detect incipient faults and abnormal events of high voltage assets. Some case studies on power transformer and overhead transmission line are presented. Results show that I-V Lissajous pattern is a promising technique for real time asset management of high voltage critical equipment.