The thesis investigates the optimal expansion planning of substations for the distribution system of Taipei City District of Taiwan Power Company. The small area load forecasting is executed with the support of Outage Management System(OMS) database. The capacity expansion of distribution substations is obtained by considering the annual load growth of each service area to achieve the cost effectiveness of substation investment. The geographic information of each service zone has been retrieved form the OMS data. With the land use planning of Taipei City Government, the load density of each small area for the target year is derived according to the final floor area and development strength of the land base. The load forecasting of each small area is then solved by considering the load growth of each customer class, which is then used for the expansion planning of substations. After determining the small area load forecasting for the final target year, the center of gravity method is applied to find the geographic blocks of all substations and the corresponding service areas at the target year. The power loading of each small area is used to calculate the power loading loss of which service area to solve the optimal location within the block for each substation. Based on the annual load forecasting of all small areas, the expansion planning of distribution substations for Taipei City District is derived by Dynamic Programming(DP) and Immune Algorithm(IA) to achieve minimization of power loading loss with subject to the operation constraint. By the proposed methodology, the unit commitment of distribution substations is determined to meet the load growth of service area and achieve power loading loss minimization of distribution systems.

When a permanent fault occurs in distribution systems, the fault location should be detected, isolated and the un-faulted but out of service areas have to be restored. The outage areas can be minimized by the switching operation based on the system load characteristics. By integrating the Outage Management Information System (OMIS), the connectivity of customers and feeder/transformer, the Customer Information System (CIS), the Automated mapping /Facility Management (AM/FM) with the customer load patterns, the hourly load demand and the service priority index of each distribution feeder and each service zone are calculated. By this way, the service restoration of the most power demand and customers can be obtained for the fault contingency of distribution system. To enhance the effectiveness of switching operation for fault contingency of distribution system, the Expert System with CLIPS has been developed by considering the operation rules in the application software program. A underground distribution system with 26 feeders in Kaohsiung District of Taiwan Power Company has been selected for computer simulation to solve the proper switching operation by taking into account the service priority of customers. It has been verified that the proposed methodology can restore the customer power service effectively by Expert System with distribution operation rules.