Power Hardware In-the-Loop validation of DC-DC power converter for offshore wind energy

September 2nd, 2019|

he paper describes the development of a power converter small scale mock-up and a real time model of an off-shore wind farm. A Power Hardware In-the-Loop validation is proposed for a demonstration of grid architecture and control principles. The paper presents the design methodology of the PHIL test bench and underlines the contribution of PHIL in the design flow of power converter development for DC grid application. Experimental results of preliminary PHIL tests are presented.

Comparaison and assessment of implementation techniques for dynamics MMC type models

September 2nd, 2019|

Modeling Modular Multilevel Converters requires a special attention due to the strong associations between the accuracy and the complexity of models on one hand and the accuracy and simulation speed on the other hand. This paper investigates different implementation techniques for MMC models and gives an overview about their development and rapidity.

Numerical modelling and influence of defects on space charges in epoxy resin under HVDC stresses

August 29th, 2019|

Space charge accumulation on High Voltage Direct Current Gas Insulated Substations can produce electrical field reinforcements in the insulation that need to be taken into account in the equipment design. The TSM (Thermal Step Method) is one of the experimental techniques allowing to determine space charge distributions in insulating materials. However localized defects (i.e. microvoids, delaminations etc) cannot usually be detected by this technique. A new numerical approach to study the influence of structural defects on Thermal Step Method currents is proposed. The method is based on a Finite Element numerical simulation allowing to simultaneously solve electrical and thermal equations. The effect of three different defects were studied. It results that ring defects, with diameters smaller than 0.4 mm, produce less than 10% of change on TSM current signals. This confirms the difficulty to detect small defects by this method. It was also observed that delaminations can produce variations in signal as high as 70%, and even generate signals of opposing sign from the case without defect.