Sizing & Allocation of PV Units in Distribution Systems

Abstract

The thesis focuses on allocation and sizing of PV units targeting the minimization of total cost of electricity purchase from the grid taking in consideration the capital cost of the units. The PV sizing and allocation problem is formulated as a mixed integer non linear programming (MINLP) problem where the objective is to supply local loads and if excess generation is available, the PV system would sell electricity back to the grid. The study is performed on the 13 bus radial feeder. The allocation and sizing problem of PV units is performed following two approaches. In the first approach, the problem is studied under demand-supply balance; while in the second approach, the problem is investigated under AC power balance. Since claims about PV units’ payback time exist in practice, this thesis considers a different strategy based on which it would calculate the PV units payback time. It considers the capacity factor of PV units that represents a percentage of PV output power depending on the availability of solar radiation. The proposed problem formulation in this work can become a good tool for both utility and customers. For utilities, the model proposed can provide an insight on the price of electricity that should be paid for green PV energy. From a customer’s perspective, the proposed model can provide the customer with a more accurate estimate of the PV payback time since the model takes into account the variability in PV as well as the fact that not all PV generation will be exported to the grid at a given moment. It would set the prices at which the customer would sell electricity to the grid at certain age of PV units and would investigate the PV operation period at which the system would consider their availability to be an advantage at the current PV electricity selling price as available in the market. Finally, the model presented in the study can be adapted to fit any region in the world taking into account two major factors, the electricity market price in the area and the capacity factor of PV units.