Distributed generation on distribution system voltage regulation: An optimization-based approach

We propose two optimization-based models for computing the allowable penetration level of multiple distributed generators, taking into account voltage regulation constraints. A single level optimization model is developed for computing the maximum penetration level, while a bi-level optimization model is developed to answer the question as to at least how much power a distribution system can accommodate. In the suggested models, on-load tap changing transformer is modeled in detail with a switch function, and the impact of distributed generator outages is included. Questions also answered in this study are how on-load tap changer can oscillate and what roles distributed generators play in this regard. Numerical algorithms are described, together with the simulation results of a 112 bus system.