Optimal balancing of large unbalanced loads using shunt compensators

Shunt compensators (SCs) with variable susceptances are commonly used for balancing of large unbalanced loads. The control of a balancing SC utilises Steinmetz's method based on correction of the unbalanced load (UL) to a fully balanced one with unity power factor. This paper presents a model for a balancing SC which extends the SC's capability to providing any desirable levels of the system balancing and reactive power compensation. The model includes system constraints and provides a full range of possible solutions. Based on this model, the analysis of the SC's parameters is performed for full and partial balancing with a focus on reducing power ratings of the SC's primary plant. The calculation technique for optimal parameters of a balancing SC is proposed and illustrated by example.