Different surge arrester configurations are studied for a modular multilevel converter (MMC) in a symmetrical monopole configuration. Each configuration is analyzed under fault conditions including DC side faults and faults inside the converter station. The configurations considered are compared in terms of overvoltages, current levels and energy dissipation.
The Energy Management Control of MMC by SuperGrid Institute was presented in Japan this week at the CIGRE-IEC 2019 Conference on EHV and UHV (AC & DC), generating stimulating discussions about this new technology.
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.
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.
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.
SuperGrid Institute and IMDEA joint forces with the support of REE, and created a consortium. This consortium was selected from more than 80 projects. Through the "Reduced Inertia Transient Stability Enhancement" (RITSE) project, SuperGrid Institute will strive to improve the transient stability of the AC networks by coordinating the use of batteries and HVDC links.
This work proposes a method for the full development, from conception to implementation, of the supervisory control of a multi-terminal HVDC (MT-HVDC) system.
The role of Modular Multilevel Converters (MMCs) in HVDC grid greatly differs depending on whether it is an offshore or an onshore station. From the common point in their control schemes, an unexploited ability of the MMC—the controllability of the internally stored energy—is identified in both offshore and onshore applications. The virtual capacitor control, previously proposed by the authors, makes use of this degree of freedom to provide energy contribution to the DC grid. The impact of this control is demonstrated by time-domain simulations of a five-terminal HVDC grid.
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