@article{mobarrez_kashani_bhattacharya_2016, title={A Novel Control Approach for Protection of Multiterminal VSC-Based HVDC Transmission System Against DC Faults}, volume={52}, ISSN={["1939-9367"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84988908478&partnerID=MN8TOARS}, DOI={10.1109/tia.2016.2565458}, abstractNote={Overall performance of the voltage source converters (VSCs) has improved during the recent years. Improvement of the VSCs along with the attractive features of the VSC-based high-voltage direct current (HVdc) transmission systems over the thyristor-based HVdc transmission systems make it possible to build multiterminal VSC HVdc transmission systems. However, the VSCs are vulnerable against dc-side faults and a method needs to be employed to interrupt the dc fault current. In this paper, three different configurations of solid-state dc circuit breakers (CB) for protection purposes are studied. Moreover, a new control method to protect the VSCs against the dc-side fault is proposed. The new method makes it possible to interrupt the dc fault current with the existing ac breakers on the ac-side or with the lower rating solid-state (SS) direct current circuit breakers (DCCBs). The performance of the SS DCCBs and the proposed method are studied using real-time digital simulator.}, number={5}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Mobarrez, Maziar and Kashani, Mahsa Ghapandar and Bhattacharya, Subhashish}, year={2016}, pages={4108–4116} }
 @inproceedings{babaei_kashani_bhattacharya_2014, title={Instantaneous fault current limiter for PWM-controlled Voltage Source Converters}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84900430903&partnerID=MN8TOARS}, DOI={10.1109/apec.2014.6803622}, abstractNote={The PWM-controlled Voltage Source Converters (VSCs) are commonly used in industrial and utility applications. In spite of superior features of fast voltage regulation and stable DC-link voltage, PWM-controlled VSCs have the major drawback of being sensitive to the grid disturbances especially the unbalanced conditions and system faults. Unbalanced input voltage generates large negative sequence current flow into the converter which results in oscillations with twice the line frequency on the DC-link voltage. This negative sequence current flow might damage the semiconductor switches. Beside the negative sequence voltage, the input voltage distorted with other harmonics also causes converter performance deterioration by producing harmonics on the DC-link voltage. This paper presents an alternative solution to improve the PWM-controlled VSC performance under unbalanced conditions and system faults and also under distorted input voltage condition caused by other harmonics rather than the negative sequence voltage. This solution is based on direct calculation of the negative sequence (or other harmonics) reference voltage without using any current regulator. This elimination of the current regulator makes the proposed controller very fast and robust. The effectiveness of this solution has been validated by simulation and Hardware-In-the-Loop test.}, booktitle={Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC}, author={Babaei, S. and Kashani, M.G. and Bhattacharya, Subhashish}, year={2014}, pages={2286–2292} }
 @inproceedings{kashani_babaei_bhattacharya_2013, title={SVC and STATCOM application in Electric Arc Furnace efficiency improvement}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84899437744&partnerID=MN8TOARS}, DOI={10.1109/pedg.2013.6785641}, abstractNote={Electric Arc Furnaces (EAF) are high power industrial loads which cause power quality problems at all voltage levels due to their unbalanced and nonlinear characteristics. The rapid, stochastic large swings in real and reactive power required by the arc furnace causes voltage drops, rapid voltage variation and distortion across the ac supply network. These voltage drops and fluctuations not only have negative impact on the power system quality and other loads, but also have an effect on the arc furnace operation, power output and efficiency. Hence, some sort of reactive compensation is required to limit the voltage disturbances injected by arc furnace into the electric power system. In this paper, an accurate electric arc furnace model, whose parameters have been set according to a 80 MVA actual arc furnace, is studied. A Static VAR Compensator (SVC) is simulated in PSCad and Real Time Digital Simulation (RTDS)/RSCAD platform for the purpose of comparison of voltage regulation at EAF bus. It is shown that the SVC mitigates the reactive power fluctuations in addition to providing the fundamental reactive power, and regulates the Point of Common Coupling (PCC) bus voltage precisely during the arc furnace operation. To verify the PSCad simulation results and make a comparison, a real time simulation study based on Real Time Digital Simulation (RTDS)/RSCAD platform has been performed in this case. On the other hand, a 80 MVA static synchronous compensator (STATCOM) is simulated in PSCad. It is illustrated that the SVC is inherently limited in its ability to respond rapidly to the fluctuating arc furnace load. It is found that the transient performance of the EAF voltage in case which equipped with the STATCOM is better than the case equipped with SVC. It is also demonstrated that although the voltage regulation by the SVC compensates a portion of the reactive power fluctuation, it is completely unable to supply any portion of the fluctuating real power drawn by the arc furnace, while the STATCOM can supply those components of active and reactive power fluctuation. The STATCOM will not normally have a source of real power connected to its DC terminals. It is therefore unable to supply sustained real power or real power fluctuations. With suitable choice of DC capacitor, however, it is capable of supplying in large part the fluctuating real power requirement of the furnace.}, booktitle={2013 4th IEEE International Symposium on Power Electronics for Distributed Generation Systems, PEDG 2013 - Conference Proceedings}, author={Kashani, M.G. and Babaei, S. and Bhattacharya, Subhashish}, year={2013} }