DESIGN CONSIDERATION AND OPERATIONAL EXPERIENCE OF DC BATTERY/CHARGER SYSTEM WITH AUTOMATIC BATTERY TEST IN DISTRIBUTION SUBSTATIONS

摘要

The reliability of power system protection and control depend on the reliability of DC supply system. Traditionally, reliability of DC supply for power system protection is ensured by duplicate battery/charger systems with extensive maintenance efforts such as regular shallow/deep discharge tests. However, the resources necessary to implement such arrangement in distribution network will be tremendous. After careful consideration of the technical advantages and cost impact of alternative battery/charger arrangements, single 'maintenance free' battery bank and charger system was chosen for the new 22kV distribution network introduced in Hongkong Electric. To reduce maintenance effort while maintaining high availability of the DC system, a battery/charger system equipped with sealed lead acid battery and automatic battery test function was chosen. After one year of service experience and evaluation, modular switching mode charger was chosen for full-scale installation.