Partial discharge monitoring system for CLP power strategic 400 kV GIS extension at black point power station

Abstract

CLP Power Hong Kong Limited (CLP Power) has reinforced its 400kV power grid by introducing new extension switchgear to the Black Point Power Station (BKP). Since the circuits are of strategic importance to provide more generation infeed capacity and any fault must be avoided by all means, if possible, to ensure high supply reliability, CLP Power has created a cooperative arrangement with Mitsubishi Electric, the original equipment manufacturer of the 400kV gas insulated switchgear (GIS) for BKP to establish an effective solution using the condition-based maintenance (CBM) approach. So an On-line partial discharge (PD) monitoring system has been installed with operation and maintenance support from the manufacturer. The design of the PD coupler has been integrated with the GIS design, with high sensitivity and reliability, while meeting recognized standards. The system can also cope with future expansion. Establishing a methodology on how to diagnose the insulation healthiness of GIS using the PD monitoring system is of high importance to the CBM practice. The PD monitoring system has been working satisfactorily since its full commissioning in June 2008. There is also a good collaboration between the teams in building up the future CBM requirements through the analysis of PD monitoring data and providing expertise support.The paper is intended to share (a) the information on key technical requirements, system design, architecture, layout arrangement and provisions on the GIS of the PD monitoring and, (b) the experience in factory acceptance test, site acceptance test and subsequent operation of the system.