Redispatch with power flow decomposition and power transfer distribution factors methods

Abstract

Electric power grids are slowly reaching their transmission limits which is mainly due to the growing use of renewable and distributed energy sources and the phase-out of conventional power plants. This increases power system operation complexity and transmission distances. Consequently, the risk of network congestions has permanently grown especially in central Europe. Nevertheless, line congestions in the power grid must be remedied as soon as possible. Therefore, the control room staff has to apply a suitable remedial action to overcome such critical situations. Redispatching is a very often-used remedial action to avoid line congestions. This paper introduces two different methods of power grid sensitivity calculation for redispatch planning. The first method, so-called Power Flow Decomposition (PFD), uses a specific way to linearize the nonlinear power flow equations in the operation point without virtually leaving it for linearization purposes. The second one, AC Power Transfer Distribution Factors (AC-PTDF) method, provides an accurate prediction of network currents and mathematical approximation of the quadratic power flow equations.