Active Control of Power Flow in Distribution Network Using Flexible Tie Switches

To accommodate high penetration of distributed generation (DG), the distribution network is moving towards the direction of active control and active management. This paper presents a new type of flexible tie switch (FTS), installed in place of traditional sectionalizers or tie switches, which can be applied for active power flow control in a distribution network. FTS can potentially optimize the existing network capacity so as to accommodate more DGs. In order to analyze its effectiveness, the simplified mathematical model of FTS in dq coordinates was first derived. The dynamic power control performance of FTS was studied in PSCAD with typical dual closed-loops control algorithm adopted. Minimum network losses and voltage profile optimization were set as the goal of power flow control. Multi-objective optimization function which takes FTS as control variable was built, considering voltage deviation constraint, capacity limitation of FTS and its power losses. Hybrid particle swarm algorithm was used to search for optimal solution under different load level conditions. Results show that the network losses are reduced significantly and the voltage profile is also optimized, when FTSs are used for power flow control in a distribution network.