ACTUAL LINE AMPACITY RATING USING PMU

Modern technology of synchrophasor measurement allows continuous evaluation of topical line transfer capacity (ampacity) with respect to line load and weather conditions. The following article explains conditions, limitations and principles of methodology and presents results of experimental measurement. The current secure reserve of line transfer capacity can be used to solve critical situations in the network. AMPACITY – LINE TRANSFER CAPACITY The ampacity or line transfer capacity problem started to be topical around the world in connection with power blackouts after 2000 and with the production of large volumes of energy by distant renewable sources (wind and solar power stations). Such power volumes has to be transferred over large distances and local (national) power networks are often used for this task regardless of the fact that the local networks have not been built for such operational conditions. Building and usage of new lines is limited by long building period, unprepared projects and high costs. Enlargement of transfer capacity or utilization of entire transfer capacity is necessary both in normal conditions and in critical conditions of interconnected networks. These problems drew attention of specialists community already before 2002 when international standards CIGRE and IEEE for mathematical models originated [1]. Definition: “The ampacity of a conductor is maximal current which will meet the design, security and safety criteria of a particular line on which the conductor is used”