Holistic approach for asset management of medium voltage switchgear in HK electric

HK Electric is responsible for providing reliable electricity supply to Hong Kong Island where the power density is among the highest in the world. Dual distribution voltages, 22 kV and 11 kV, have been adopted by the Company. The 11-kV network was first introduced in 1970s with open-ring network configuration. For improving network resilience and reducing cable mutual heating, 22-kV network using closed-ring configuration was introduced in 2000s. Currently, our customers continue to enjoy a world-class supply reliability of over 99.999%, a record we have maintained since 1997. In recent years, the supply reliability even surpasses 99.9999% and the customer minutes lost was reduced to below 0.5 minute. One of the contributing factors in achieving such high reliability is the good performance of Medium Voltage (MV) switchgear in our distribution network. With the ever-increasing expectation of high supply reliability and power quality, a holistic approach in managing our MV switchgear assets is essential. This holistic approach not only increases the reliability of the aged assets and reduces maintenance costs, but also addresses the risks associated with operational health and safety. The management of the entire MV switchgear asset life-cycle can be achieved by incorporating hazard identification and mitigation measures right from the design stage, followed by regular and ad-hoc operational reviews, making use of latest technological advancement and management skills, upgrading of asset, formulating and conducting condition monitoring and refurbishment throughout their useful service life. This paper presents the holistic approach adopted by HK Electric for managing MV switchgear asset and the enhancements implemented.