Harmonic performance analysis of an OPWM-controlled STATCOM in network applications

The method of selective harmonic elimination is often used as an efficient means for obtaining harmonic-reduced waveforms from voltage sourced converters (VSC). However, the switching angles required for its implementation are usually pre-calculated on the basis of a fixed dc bus voltage. In practice, there are harmonies present in the dc source because of the finite dc bus capacitance and other realistic operating conditions, which can potentially introduce additional noncharacteristic harmonics. This paper examines the harmonic performance of a VSC-based static synchronous compensator as a function of design and operating parameters. These include the value of dc capacitor, the strength of the connected ac network and ac system unbalance. The results are generated using theoretical analysis for special cases and numerical simulation using electromagnetic transients simulation for the more general case

Implementation and Performance Evaluation of a Reclosing Method for Shunt Reactor-Compensated Transmission Lines

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)This paper proposes a new control method to reduce overvoltages due to three-phase reclosing for shunt compensated transmission lines (TL). The method detects the first minimum voltage region of the beating across the circuit breakers after protection dead time and works independently of voltage zero crossing, reducing significantly the reclosure time. The controller was tested on a Real Time Digital Simulator (RTDS) and its performance was compared to the traditional preinsertion resistor approach and another existing control method.262954962Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)NSERC, CanadaConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP