Advanced transformer control modeling in an optimal power flowusing Newton's method

摘要

This paper reports on advanced transformer modeling facilitiesnsuitable for large-scale optimal power flow studies. The new transformernmodels are developed from first principles and incorporated into annexisting Newton-based optimal power flow computer program for highlynrobust iterative solutions. A three-winding transformer model with tapnratios in all three windings is shown to be a general case for existingntwo-winding transformer models and the classic load tap-changing andnphase-shifting transformer models. The newly developed transformernmodels add a great deal to software flexibility and are amenable to morenrealistic electric energy studies. This is partly due to the transformernmodels being fitted with complex tap changers in each winding and annonlinear representation of the magnetizing branch. The three-windingntransformer model interfaces easily with reactive power plant models,ne.g., static VAr compensators