Towards a Practical Partial Core Transformer - Compensation of Reactive Power Requirements with a VSC
Partial core inductors and transformers for high voltage testing of generator insulation have been designed, developed and built by the University of Canterbury since 2002. A partial core transformer is a compromise between a traditional full core and coreless transformer. It consists of a laminated ferromagnetic central core around which the primary and the secondary windings are wound. The outer limbs and the yokes are not present. This makes a partial core transformer superior to its full core counterpart as far as cost, weight and ease of transportation are concerned, while maintaining its functionality. The lack of a closed core reduces the magnetising reactance (Xm) and increases the reactive power requirement of the partial core transformer. This paper deals with the application of a single phase voltage source converter (VSC) based STATCOM to a low voltage partial core transformer, to compensate the inherent higher lagging VArs of the partial core transformer. Hence the transformer, with an added compensator, can be used like a normal full core transformer. The single phase partial core transformer with a STATCOM is modelled using PSCAD/EMTDC software. A simple, yet robust control system is designed. Simulation results reveal the performance of the STATCOM and partial core transformer with inductive, capacitive and resistive loads.