Application of condition monitoring techniques in managing the 11kV switchgear in HK electric

For a world class city like Hong Kong, reliable electricity supply is essential to business and to maintain good quality of life. To meet the community´s expectation for high electricity reliability and to ensure the healthiness of the equipment, refurbishment and maintenance regime has been migrating from conventional time based preventive maintenance to reliability centered maintenance aided by various proven condition monitoring techniques. Switchgear fault will lead to supply interruption and affect power quality. It is, therefore, important to detect abnormal activities including partial discharge inside the switchgear in the early stage so that expedient action can be taken to avert discharge defect from developing into fault. This paper presents the condition monitoring techniques which have been applied by HK Electric in managing its 11kV switchgear to help achieve a world class supply reliability rating of more than 99.999%.