| Popis: |
The HVDC transmission is typically utilized for connecting long distance or asynchronous AC networks. The two most common HVDC technologies are voltage source converter HVDC (VSC-HVDC) and line commutated converter HVDC (LCC-HVDC). Although VSC-HVDC has enhanced control features along with non-dependence upon synchronous machines for commutation, it suffers from higher cost and higher losses due to the involvement of high-speed switching, requires sophisticated gate driver circuitry, has a weak overload capability and suffers from lower reliability due to higher component count. This paper focuses on the highly mature LCC-HVDC technology and aims at enhancing its reliability along with reduced control complexity by proposing a novel transformerless power electronics-based module integrated between the neutral and ground of HVDC inverter-side transformer. The module introduces a variety of smart features in conventional converter transformer, such as, harmonics isolation, voltage regulation, voltage and impedance balancing. This enhances LCC-HVDC robustness against commutation failure, reduces DC power recovery time and control complexity while protects it against certain natural and man-made disturbances, such as, solar storms and high-altitude nuclear detonations. The proposed approach is evaluated in PSCAD/EMTDC for the CIGRE HVDC benchmark model that highlights its promising performance. |
