DETERMINING MAXIMUM REGULATING CAPABILITY OF UPFC BASED ON PREDICTINGFEASIBILITY LIMIT OF POWER-SYSTEMS

This paper presents a novel procedure to determine the maximum regulat ing capability of a unified power flow controller (UPFC) by using opti mal multiplier power flow. The capabilities of flexible ac transmissio n systems (FACTS) equipment are not only constrained by their thermal limits and the steady-state security limits, but also limited by their feasibility limits. After the detailed analyses have been made on the use of optimal multiplier mu as a new predictor to estimate the bound ary point of the feasibility region, an algorithm for determining the UPFC regulating capability is proposed. The approach is then compared with minimum singular value decomposition on the IEEE 30 bus system. T he results clearly demonstrate the effectiveness of the proposed appro ach.