Transient Performance of a Multi-Terminal HVDC Transmission System Feeding Very Weak AC Networks
S. Seenivasan1, S. Singaravelu2

1S. Seenivasan, Department of Electrical Engineering, Annamalai University, Annamalainagar-608002, Tamil Nadu, India.
2S. Singaravelu, Department of Electrical Engineering, Annamalai University, Annamalainagar-608002, Tamil Nadu, India.
Manuscript Received on July 01, 2015. | Revised Manuscript Received on July 08, 2015. | Manuscript published on July 20, 2015. | PP: 12-25 | Volume-3 Issue-8, July 2015. | Retrieval Number: H0647073815/2015©BEIESP
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Abstract: This paper analyses transient performances of a line commutated converter (LCC)-multi-terminal HVDC transmission system (MTDC) feeding very weak AC networks with firefly algorithm based optimal proportional-integral (PI) controller for rectifiers and inverters control and hybrid reactive power compensators (RPC’s) at inverters AC side. The hybrid compensator is attained by equally mixing the fixed capacitor (FC) with any one of the following compensators: synchronous compensator (SC); static var compensator (SVC); static synchronous compensator (STATCOM). The MTDC transmission system model is simulated using Matlab. The transient performances of hybrid RPC’s (FC+SC, FC+SVC and FC+STATCOM) are investigated during various fault conditions and the results are compared with the performance of the SC, SVC and STATCOM to focus the supremacy of the hybrid compensators. The simulation results authorize that the equal combination of FC and STATCOM has a steady and fastest response. The outcomes also demonstrate the superiority of the firefly algorithm based optimal PI controller over the conventional PI controller. The harmonic existing in the inverter AC side is also observed under steady state operation to assure the quality of power supply.
Keywords: Firefly algorithm, Hybrid RPC, MTDC, PI controller, Very weak AC system.