of the power systems in network planning is likely to lead This paper discusses the merits of an analytical method for to higher system costs and reduced reliability. This paper determining the location and amount of series addresses transmission capability limits and concerns itself compensation to increase the steady state power transfer primarily with planning decisions. capability in the power system based primarily on cascading line overload considerations. Steady state transmission limits deJne the boundaries of a power system operating point. This paper presents tools to identi3 these boundaries and analytically estimates the change in the boundary limits due to the application of series and shunt compensation. The approach identiJies critical lines that can initiate cascading line outages and identifies the optimal location and amount for series compensation. The methodology can also be used to select sites for devices that can extend the mailability ofpower in $0 wgates.