Harmonic and balance compensation using instantaneous active and reactive power control on electric railway systems

Abstract

This work presents a general filtering and unbalance compensation scheme for electric traction systems. The proposed method uses an active filter controlled with the instantaneous active and reactive power, to reduce the harmonic current distortion and the negative sequence obtained by the system under unbalanced operation in steady state. The proposed filter is evaluated using open delta (V-V) and Scott transformers in the power substation. The scheme has been simulated and experimentally validated. Experimental and simulation results show the controller advantages and the applicability of the proposed method in railway systems .

Improved grid voltage sensorless control strategy for railway power conditioners

“…To effectively alleviate the impact of electrified railways on the power quality of the utility grid, various techniques have been proposed [7][8][9][10][11][12][13][14]. Although some methods can be helpful to improve the power quality to some extent, they cannot be considered as a comprehensive approach for power quality compensation.…”

“…Although some methods can be helpful to improve the power quality to some extent, they cannot be considered as a comprehensive approach for power quality compensation. Sequence rotation, reasonable locomotive operation modes or using balanced transformers and so on can attenuate the effects of negative‐sequence contents (NSCs) on the grid [7, 8]. Nevertheless, these methods are not flexible and the system cannot maintain its balanced condition under variation of traction loads.…”

Comprehensive study on the power rating of a railway power conditioner using thyristor switched capacitor

“…Electric railways impose several power quality problems to the utility grid [1]. These problems mainly consist of large negative sequence current (NSC), undesirable harmonics and low power factors [2][3][4][5][6][7][8], which may be caused additional system losses, overheat rotating machine, malfunction of protection relays and measuring instruments [9,10].…”