Reliability Modeling of AC Filter in UHVDC Link Based on Reactive Power Compensation and Harmonic Performance Evaluation

Considering reactive power compensation and harmonic performance evaluation, the reliability model of the AC filter (ACF) in ultra high-voltage direct-current link is newly proposed. The state-space models of the filters are combined by matrix description to obtain transfer rates among the states that represent the configuration schemes, i.e., the type and number of the available filters. The sensitivity model of the combined ACF subsystem is proposed to find out the weakest filter. Due to failure of the filters, both lack of reactive power compensation and harmonic current, which exceed the limit, cause loss of the transmission capacity. The fundamental and harmonic power flow models are proposed to quantify the compensated reactive power and evaluate the harmonic indices, by which the configuration schemes are grouped with the capacity levels (CLs) of the transmitted power and regrouped to satisfy the harmonic standards. The numerical results demonstrate that the transitions among 100% CL, 75% CL, and 50% CL to 0% CL appear, due to which, the configuration schemes, which are grouped by the reactive power compensation but do not satisfy the harmonic standards, are removed to the group of 0% CL.