Characteristics of transformerless MMC-based HVDC systems and the principle of decentralized controlled potential definition
Conference: Internationaler ETG-Kongress 2013 – Energieversorgung auf dem Weg nach 2050 - Symposium 1: Security in Critical Infrastructures Today
11/05/2013 - 11/06/2013 at Berlin, Deutschland
Proceedings: Internationaler ETG-Kongress 2013 – Energieversorgung auf dem Weg nach 2050
Pages: 6Language: englishTyp: PDF
Personal VDE Members are entitled to a 10% discount on this title
Authors:
Heising, Carsten; Bartelt, Roman (Avasition, Dortmund, Deutschland)
Staudt, Volker; Steimel, Andreas (Ruhr-Universität Bochum, Bochum, Deutschland)
Menze, Andreas; Rathke, Christian; Lebioda, Thomas Jan (TenneT Offshore, Bayreuth, Deutschland)
Abstract:
Up till now converters of HVDC systems are connected to the electricity grid by transformers. This limit short-circuits currents, mitigates zero-sequence components caused by the switching of the converter valves and offers a potential separation. Especially with view on offshore applications, transformerless concepts were considered early to reduce costs and weight. Modern self-commutated modular multilevel converters allow now the realization of such concepts effectively. This paper analyses the transformerless construction of a HVDC system with special regard to the binding of electric potentials. It demonstrates that under fault conditions effective current limitation and mastering of overvoltages is viable. Compared to transformer-based solutions, many advantages result especially if DC cables have to be protected from overvoltages.