An Efficient Algorithm for Dispatch of Modular FACTS devices in Transmission Planning

With growing uncertainty in the underlying assumptions that are used to plan for a secure operation of the electric power grid, planning engineers are looking for more flexible transmission upgrade in which to invest. One such technology is modular flexible AC transmission systems (M-FACTS), notably variable impedance power flow control devices (VI-PFC). VI-PFC technology can be used to route power through parallel paths in the transmission system, thereby eliminating congestion. This technology can also be used in the reliability context of resolving intact and post-contingency overloading. The true value of VI-PFC technology is its ability dynamically increase or decrease reactance of a line, making it more flexible than fixed series reactors or series capacitors. The first step in unlocking this value is to enable transmission planners to incorporate these optimal dispatches in their planning studies. This paper develops an efficient method to optimally dispatch multiple VI-PFC deployments to resolve post-contingency overloads from a planning perspective. The dispatch method is based on a PTDF DC power flow formulation. However, the method is illustrated on the IEEE 39-bus test system solving with full AC power flow assumptions.