MEDOW Researchers Introduce Their Grid-Related Work

In February 2015, three MEDOW researchers presented their work at the 11th IET International Conference on AC and DC Power Transmission (ACDC 2015) in Birmingham, UK.

Robert Renner’s work concentrates on optimal DC reference voltage in HVDC grids. The paper introduces a method to find the optimal DC voltage in a HVDC grid based on power flow and line resistances. The method is implemented in the open-source software MatACDC and the results are verified by dynamic simulations in DIgSILENT, using a one area DC voltage restoration controller.

Alejandro Bayo Salas’s paper is titled “Impedance-based Stability Assessment of Parallel VSC HVDC Grid Connections” and presents the stability analysis of a system with two converters. The impact of converters that may interact with each other through the network is studied in the frequency domain by using an impedance-based approach. This approach shows potential for studying the interactions in larger networks. Simulation results show that the stability is compromised when a parallel converter is connected.

Agustí Egea-Alvarez discussed capability curves of a VSC-HVDC connected to a weak AC grid considering stability and power limits. The paper analyses the limitations on the power flow transfer through a VSC-HVDC system connected to a weak grid. It is shown that an additional Q-support of 0.2 pu can maintain the transfer of full power without the need for oversizing the VSC.

MEDOW is co-ordinated by Cardiff University and has four other university partners, five private sector partners and one associate partner. Collectively, staff from the partners organisations have the wide-ranging experience and expertise to provide the appointed researchers with
broad-ranging training in DC grid technologies.

All partners will host at least one researcher, and associate partner National Grid will provide training
and steering to the consortium.

Image: MEDOW; Feature image: SUSPLAN (Illustration)