The main objective of this thesis is to develop a methodology to size PETT topologies, in order to compare them.
This paper presents an overview of the dc–dc power converters dedicated to HVdc proposing a classification based on their structure. Two large families are established: those which provide galvanic isolation, and those which do not. Several subfamilies are also proposed. An overview of the main HVdc applications that can be targeted with each family is also presented, highlighting the main converter requirements for each application case.
PhD Amjad MOUHAIDALI « Contribution to the modelling of HVDC cables for electromagnetic transient simulations »
The integration of new technologies in the electric grids made them more and more complex, and most likely future growth of power grids will be based more on underground cables than overhead lines. One problem here, is that the mathematical model for electromagnetic simulation of power cables still has some shortcomings regarding stability, accuracy and passivity. In this thesis, we evaluate the cable parameters using analytical and numerical methods.
PhD Juan-Carlos GONZALEZ « Transient stability of high voltage AC-DC electric transmission systems »
This thesis addresses the transient stability analysis of hybrid AC/DC electric transmission systems. More precisely two questions sought to be investigated: What is the impact of a DC contingency on AC transient stability? How can we take advantage of the DC transmission systems as control inputs in order to enhance AC transient stability?
This paper provides a fault analysis of bipolar overhead line based HVDC grids using HB-MMC converters. The impacts of fault type and fault resistance are shown and the physical behaviour of the transient fault return current is explained.
The Failure Mode Effect Analysis (FMEA) is a technique used to investigate failures in a process or component and to identify the resultant effects of these failures on system operations. In this paper it is explained how the FMEA can be used to define and assess the impact of the failure modes (FM) of a protection strategy for High Voltage Direct Current (HVDC) grids.
This paper studies the role of DC-DC converters in the protection of HVDC grids acting as firewalls to stop the propagation of faults. The effects of blocking the converter or actively controlling its operation during faults are presented.The results demonstrate the capabilities of DC-DC converters beyond DC voltage transformation.
Power system stability enhancement via VSC-HVDC control using remote signals: Application on the Nordic 44-bus test system
In this paper the benefits of embedded VSC-HVDC links with supplementary controls for small-signal stability enhancement purposes using remote signals are studied and applied on the Nordic Grid.