Subsynchronous resonance in a series-compensated Great Britain transmission network

In Great Britain (GB), increased levels of wind penetration require substantial reinforcements for transmitting power from Scotland to England. In the National Grid 2020 Vision, offshore and onshore infrastructure reinforcements have been proposed, the inland reinforcement including series compensation (fixed capacitors). A possible detrimental effect of onshore series compensation is the appearance of subsynchronous resonance (SSR). SSR caused by the interaction between turbogenerators and a series-compensated electrical network is studied. A three-machine system representing the onshore-reinforced mainland GB system is examined. The effect of series compensation equipment on SSR is assessed. The effects of quadrature boosters in the network are also investigated. Time-domain simulations are carried out in power systems computed aided design (PSCAD) whereas system modelling and eigenvalue analyses are conducted in MATLAB.