Variable order and variable step-size integration method for transient analysis programs

A variable-order and variable-step-size integration method using the backward differentiation formulas (VOVS-BDF) is introduced to optimize numerical integration orders and step sizes for power transient analysis. The basic concept and the numerical stability of the VOVS-BDF are discussed and shown for efficient computer-aided power transient analysis. A new searching method for break points is proposed to adjust the step-sizes. The VOVS-BDF is validated through analysis examples of an instantaneously controlled inverter circuit and a single-conductor line system. The procedures for the necessary program changes are also described.<
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