Losses of HVDC converter stations need to be accurately measured and/or estimated in order to support the evaluation of bids for such systems and to underpin efforts to reduce greenhouse gas emissions.
The challenge of measurement has risen with modern converters where insulated gate bipolar transistors (IGBT) are used at high switching frequency. The theoretical bases for measurement errors are studied, both for measurement on the IGBT as a component and on complete converter stations.
The study shows that electrical measurements are difficult to augment to an accuracy level sufficient for the needs and that a supplemental method such as calorimetric measurement may be needed. In certain cases, there will be a possibility to make temporary connections to permit two converters to operate in back-to-back mode, permitting a direct measurement of losses.
The achievable accuracy is studied and estimated. The energy losses of an HVDC transmission system have to be generated in power plants supplying the system. The losses therefore represent both a direct cost for the owners of the transmission system and an emission of greenhouse gases into the environment.
Source: IEEE
Author: Anders Bergman