STATIC AVAILABLE TRANSFER CAPABILITY ENHANCEMENT USING ‘UPFC’ UNDER CONTINGENCIES

Abstract

A combination of lack of investment and environmental issues results in lack of building of new transmission infrastructure. This leads to a requirement for better utilization of existing transmission network. The ATC is defined as a measure of the transfer capability remaining in the physical transmission network for further commercial activity over and above already committed uses" This index is often used as a measure of additional power that can be securely transferred by a transmission network. The Available Transfer Capability (ATC) depends on a number of factors such as system generation dispatch, system load level, load distribution in the network, power transfer between areas and the limit imposed on the transmission network due to thermal, voltage and stability considerations. The computation of ATC is very important to the transmission system security and market forecasting. While the power marketers are focusing on fully utilizing the transmission system, engineers are concern with the transmission system security as any power transfers over the limit might result in system instability With development of power market, bilateral trade increase greatly. The higher and higher challenges to the reliable and economic operation of power grid have been posed. While Flexible AC Transmission System (FACTS) is for a new solving method, it brings an unprecedented turning point in power flow control, stability and transmission capacity and improves power system. Placement of FACTS controller may be quite effective for enhancing The ATC of power system due to their capability to improve line voltage and control power flow through lines. Out of all the FACTS devices, placement of Unified Power Flow Controller (UPFC) seems to the more effective in enhancing available transfer capability of the transmission network due to its ability to control series and shunt parameters simultaneously.