An efficient differential equation load flow method to assess dynamic available transfer capability with wind farms

Abstract

Differential equation load flow (DELF) is an innovative approach to convert a load flow model to a fictitious dynamic system. DELF solves the entire time-domain analysis of a dynamic system trajectory rather than solving load flow equations repeatedly in a set of conditions. The static available transfer capability (ATC) determination algorithm is specified through a method called the approximation of the path of the minimum distance method. In this method, instead of a repeated power flow, only three system operating points are used. An estimation of the potential energy boundary surface was also employed to determine the transient stability in an attempt to correct previous methods. A combination of static method and transient stability led to a combined approach to dynamic ATC computation. This paper proposes a truly effective and precise method to assess Dynamic ATC using the differential equation load flow considering the first contingency (n − 1) situations and the intact system condition. For various multilateral and bilateral transactions, this method was successfully implemented on 39, 118- and 300-bus IEEE, 145-bus Iowa-State, the west of Iran (1153-bus), and Mashhad MV distribution network (4438-buses) systems. The results showed a better suitability, a higher speed and accuracy than other dynamic ATC methods.