GHG Emission Control-A Proactive Electrical Asset Management Through Ultrasound Technology

The distribution utilities are thriving for reliability. So, the need of the hour was to introduce GIS Substation in 11 kV network in the way of Ring main Unit (RMU) to provide N-1 for improving reliability as well as to install substation in congested areas like metropolitan cities where the land cost is very high. As of current scenario GIS technology is very successful in MV and EHV network as the frequency of operation is very low whereas in 11 kV Network it is not so as the frequency of operation is very high. One of the major concerns from environment point of view is SF6 gas emission from the failed switchgears into the environment which is almost overlooked by the utilities as well as OEMs too.

We at TPDDL have around 5000 Nos. of 11 kV RMUs & faced around 250 Nos. of RMU failures in FY13 which resulted in Gas leakages which is equivalent to 0.0179250MMTCDE. Though the distribution utilities are sticking up to best maintenance practices available but the switch gears continue to fail leading to losses in terms of revenue and un-served energy. As the RMU is completely enclosed and maintenance free, identifying the fault at infant stage is very difficult. The focus of this paper centers on identifying criticality in the RMUs by new technology which helps the utility in maintaining the reliability as well as preventing the environment from harmful gas emission.

We use Ultrasound Technology to identify the abnormalities in the equipment by detecting the source of failure at an early stage. Any abnormality occurring in electrical switch gears is dispersed through electrical discharge which is commonly referred as Ionization. These discharges produce high frequency sound which is beyond the human audible range. Usually these high frequencies lie in the ultra sound region. Thus for their detection Ultra sound scanning tool is useful in almost all areas of power system due to its unique feature of detection of abnormality from a distance. Thus by analyzing the sound pattern based on an algorithm we check for the type of abnormality and thus the health of the equipment is detected that whether it is deteriorating or not. In addition, TPDDL has developed an android App to record all the details at site through a smart phone & the same is synchronized with the server so that all data is readily accessible for further planning & needful action. By ultrasound technology we prevented around 435 no's of RMU failure in FY 14 & FY15 which in turn saved the environment from SF6 gas Emission to the tune of 0.0311895 MMTCDE. This paper presents the proactive and predictive maintenance practices adopted by TPDDL so as to prevent untimely failure of switch gears in turn SF6 emission mitigation & also to ensure efficient working of the power delivery asset i.e. switch gears.