Optimal coordination of voltage controllable devices in distribution systems using power-based models and quadratic programming

The incorporation of photovoltaic (PV) inverters makes the management of voltage difficult for power system operators. One solution is to consider these inverter-based devices as controllable reactive power (VAr) sources and to coordinate them with other voltage regulating devices in the distribution system. This paper proposes some acceptable approximations to quickly formulate and solve a mixed-integer quadratic programming problem to periodically determine the optimal voltage coordination of a load tap changer, voltage regulators, capacitor banks, and PVs on a smart grid platform. The solution to the optimization problem is aided by an iteration-based algorithm. By using the MATLAB software to carry out the simulation and computation, the method is well verified by comparing its generated result with a trustworthy solution obtained from examining all possible coordinating combinations of voltage regulating devices and PVs in a modified IEEE 34-bus system. The effectiveness and features of the method are clearly illustrated on that test system by considering a time-varying load and PV generation. The obtained results demonstrate the practical application of this work to medium-voltage systems.