Abstract
Introduction of IPP and wheelings gives various influences to electric power systems. Especially, retail wheelings cause influences to reactive power balance and operating reserves and so on. Ancillary services for minimizing these influences to operate power system efficiently and stably are important.
This paper focuses on the ancillary services to estimate the influences by introduction of wheeling to power systems. Further, this paper tries to estimate that how retail wheelings give influences to power system operation, mainly from reactive power control and frequency control points of view. First, from reactive power control viewpoint, the influence on the transmission loss is evaluated by using Optimal Power Flow (OPF) calculation. Also, in case of providing the reactive power from IPPs, this paper proposes an index for evaluating the value of reactive power from the IPPs. Furthermore, from the frequency control viewpoint, this paper evaluates an influence of the wheelings on Load Frequency Control (LFC) capacity [MW] and LFC speed [MW/min] that electric power utilities should maintain a system frequency.
