Abstract
Infrastructure reinforcement using high-voltage direct-current (HVDC) links and series compensation has been proposed to boost the power transmission capacity of existing ac grids. However, deployment of series capacitors may lead to subsynchronous resonance (SSR). Besides providing bulk power transfer, voltage source converter (VSC)-based HVDC links can be effectively used to damp SSR. To this end, this paper presents a method for the real-time estimation of the subsynchronous frequency component present in series-compensated transmission lines—key information required for the optimal design of damping controllers. A state-space representation has been formulated and an eigenvalue analysis has been performed to evaluate the impact of a VSC-HVDC link on the torsional modes of nearby connected thermal generation plants. Furthermore, the series-compensated system has been implemented in a real-time digital simulator and connected to a VSC-HVDC scaled-down test-rig to perform hardware-in-the-loop tests. The efficacy and operational performance of the ac/dc network while providing SSR damping is tested through a series of experiments. The proposed estimation and damping method shows a good performance both in time-domain simulations and laboratory experiments.
Highlights
S ERIES compensation is a well-known method to enhance thermal and stability limits of long transmission lines
Its use brings the potential risk of subsynchronous resonance (SSR), where the electrical modes of compensated lines interact with the mechanical modes of nearby thermal generation plants [1]
subsynchronous mode (SUB) remains unaffected for set Kmin, it can be noticed that TM4 is no longer in the neighborhood of SUB and, as a result, the system is no longer unstable for 40% series compensation
Summary
S ERIES compensation is a well-known method to enhance thermal and stability limits of long transmission lines. Its use brings the potential risk of subsynchronous resonance (SSR), where the electrical modes of compensated lines interact with the mechanical modes of nearby thermal generation plants [1]. This interaction may result in torsional oscillations on the shafts of generators which, if left unattended, may lead to fatigue and failure [1]–[3]. Transmission network reinforcement using HVDC links is a well-established alternative to series compensation This technology has proven to be reliable, providing advanced functionality to network operators [4], [5]. VSC-HVDC links are being connected in parallel with existing LCC links to further enhance the power transfer capability of already compensated ac
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
