Improved Control Strategy for Subsynchronous Resonance Mitigation with Fractional-order PI Controller

• Published in: International journal of emerging electric power systems Vol. 17; no. 6; pp. 683 - 692
• Main Authors: Raju, D. Koteswara, Umre, Bhimrao S., Junghare, A.S., Chitti Babu, B.
• Format: Journal Article
• Language: English
• Published: De Gruyter 01.12.2016
• Subjects: fractional-order PI controller; SSSC; subsynchronous resonance; voltage source converter
• ISSN: 2194-5756; 1553-779X
• DOI: 10.1515/ijeeps-2016-0037

This paper explores a robust Fractional-order PI (FOPI) controller to diminish Subsynchronous Resonance (SSR) using Static Synchronous series compensator (SSSC). The diminution of SSR is accomplished by increasing the network damping with the injection of voltage of subsynchronous component into the line at those frequencies which are proximate to the torsional mode frequency of the turbine-generator shaft. The voltage of subsynchronous frequency component is extracted from the transmission line and further the similar quantity of series voltage is injected by SSSC into the line to make the current of subsynchronous frequency component to zero which is the major source of oscillations in the turbine-generator shaft. The insertion and fine tuning of Fractional-order PI controller in the control scheme of SSSC the subsynchronous oscillations are reduced to 4 % as compared to conventional PI controller. The studied system is modelled and simulated using MATLAB-Simulink and the results are analysed to show the precision and robustness of the proposed control strategy.