REVIEW PAPER Mitigation of Harmonics Present in Three-Phase Auxiliary Converter Used in the Locomotives Saurabh Kamble 1 • Chandrakant Rathore 1 • Pankaj B. Thote 1 • Anirudha Marothiya 1 Received: 11 June 2019 / Accepted: 24 July 2020 Ó The Institution of Engineers (India) 2020 Abstract In the new era where use of nonlinear loads has increased drastically in commercial, residential and industrial sector. The quality of power has degraded where the voltage and current signals are being injected with unwanted frequency components called distortions. These distortions are mainly harmonic distortions whose presence causes severe damage to the equipments connected to distorted source. Similarly, auxiliary system used to supply blowers system is facing problems of harmonics which is a major problem investigated during recent years. This paper investigates and mitigates the two major harmonic com- ponents of currents present in auxiliary converters used in locomotives. The statistical data acquired viz. total har- monic distortions (THD) and solution to reduce THD in current at different BUR’s (converters) of traction substa- tion is presented in this paper. The main focus of the paper is to mitigate two major harmonics present in blowers system used in locomotives by means of double-tuned passive filter. The proposed mitigation technique has been implemented on hardware prototype model. Keywords Harmonics mitigation Á Traction blower Á Converters Á Passive filter Introduction Locomotives are usually fed from 25 kV over head equipment (OHE) which is passed through various con- verter systems to obtain 415 V, 50 Hz, 3/ AC supply. This supply is provided to different motor systems used in locomotives for different purposes. Half controlled rectifier is the first step of converter in which two switches are controlled using pulse width modulation (PWM) technique. This half controlled rectifier is connected to IGBT-based inverter which is being controlled by PWM-based method [1]. Since all the converters consist of power electronic switches harmonics are introduced in the supply system and the presence of harmonics can lead to various losses in the system. Various factors like line conditions, harmonics impedances during installation, etc. influences the har- monic current generation in locomotive [2]. The harmonic contents in locomotives can damage various devices connected into polluted source network, like: • Losses of various equipments connected in system increases due to harmonic effects. • Torques produced in rotating equipments minimizes and becomes pulsating in nature. • Stress on insulation of equipments increases which in turn increases the aging prematurely. • Audible noise increases of rotating and static equipments. • Magnitude of current and voltages amplifies due to resonance effect. • Communication interference due to inductive coupling between power and communication circuits [3]. Railways are transforming their supply system used in traction motor system to IGBT or GTO-based drives & Saurabh Kamble saurabh2612k@yahoo.com 1 Electrical Engineering Department, SBJITMR, SBJITMR Campus, Katol Road, Nagpur, India 123 J. Inst. Eng. India Ser. B https://doi.org/10.1007/s40031-020-00474-5