The modeling of tap-changing transformers andP-Vbuses using the sensitivity impedance matrix

초록

Rapid deployment of distributed generation resources such as photovoltaic systems, wind farms, and other power electronics-based loads has emphasized the requirement for tap-changing transformers that minimize voltage variations and phase imbalances. Thus, various power-flow algorithms able to model such a tap-changing transformer have been proposed. The algorithms include a method that uses the bus impedance or admittance matrix. However, particularly the previous algorithms that use the impedance matrix did not take tap-changing transformers and P-V buses into account. Thus, this study models tap-changing transformers for a power-flow algorithm using the impedance matrix. For this purpose, it proposes a unified steady-state T shaped transformer model with a tap changer on the primary or secondary side. The proposed power-flow calculation algorithm also models P-V buses by the sensitivity impedance matrix. Since the proposed method reduces the inversion of matrices, it can be faster than the Newton-Raphson and fast decoupled methods (eg, the modified IEEE 30-bus test system added by 3000 or more nodes), not losing the accuracy.

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