A STUDY ON IMPROVING POWER SUPPLY CAPABILITY FOR 500/220KV POWER SYSTEM IN JIANGSU PROVINCE
This paper reviews the development courses of 500kV bulk transmission system in Jiangsu Province, China, and their corresponding 220kV interconnected sub-transmission systems. Each development course which has its unique and specific characters is focused and studied. With the development of 500kV transmission system into mature, a number of 220kV sub-transmission systems, among which are directly and electrically disconnected via 220kV lines or circuit breakers in operation but are electrically interconnected via 500kV system, are formed mainly due to the reason of decreasing system fault level below the limits of circuit breaker. Such isolated 220kV sub-transmission system is defined as the Island Grid (IG) in this paper. The purpose of this paper is to study the capability of power supply of IG system as well as the key factors, such as transformer impedance, influencing the capability based upon three typical models of 500kV/220kV IG system structure. Further more, the conclusions of study will be used to help us significantly increase economic system scale and efficient with the accepted security and/or reliability standard set by Regulator, especially in the case of the severe constraints of land resources and corridors to construct new transmission lines and substations. The IG system generally comprises of the power sources, such as 500kV main transformers and the generators connected to 220kV IG, the connected distribution systems which are regarded as the loads in the study, and the tie-lines to the neighbor IGs which are disconnected during the normal conditions and can be interconnected if the said IG is in contingency due to the outages of 500kV main transformer or large generator in order to maintain again the power supply capability and the security and/or reliability standard. The conclusions of this study are successfully and practically applied in Jiangsu power system planning and the transmission system expansion project development. A project commissioned in Nanjing, capital of Jiangsu Province, is that two 500kV substations were expanded and renovated with high impedance transformers, and the interconnected 220kV IG system was maintained without the grid structure modification.
500/220kV high impedance transformer 220kV island grid (IG) fault level power supply capability,
WANCHUN QI JUNHUI HUANG ZHIWEI WANG HAIQIAN WANG
POWER SYSTEM PLANNING RESEARCH CENTER, JIANGSU PROVINCIAL ELECTRIC POWER COMPANY (CHINA)
国际会议
桂林
英文
1-8
2009-10-28（万方平台首次上网日期，不代表论文的发表时间）