Power quality improvement in DC electric arc furnace plants utilizing multi-phase transformers

Abstract

SUMMARY Conventional feeding systems for DC electric arc furnace steel making plants usually include a 12‐pulse rectifier that is fed by Δ/Δ and Δ/Y three‐phase transformers. In this paper, with the use of the PSCAD/EMTDC software (Developed by Manitoba HVDC Research Center Inc., Canada), the advantages of applying multi‐phase transformers for supplying such loads are evaluated and compared with the traditional three‐phase power supply systems. A well‐designed secondary winding for multi‐phase transformer is proposed, and then the modeling of such transformers is discussed. With some proper power quality indices applied, it is shown that utilizing multi‐phase transformers can lead to power quality improvement such as current/voltage harmonic reduction and unbalance mitigation. Copyright © 2012 John Wiley & Sons, Ltd.

A new matrix converter‐based feeding system for DC electric arc furnaces and a comprehensive comparison between different types of feeding topologies

“…By comparing the obtained values in Table with the corresponding values related to the other power supplies, it can be seen that after PWM‐AC chopper‐based power supply, the proposed supply system has the lowest voltage harmonic distortion. Furthermore, it has the lowest current harmonic distortion after DC chopper‐based power supply in CCC method, and also has the lowest current harmonic distortion after DC chopper‐based power supply and PWM‐AC chopper‐based power supply in CPC method.…”

“…The recommended supplying topology is simulated in PSCAD/EMTDC software. The significant technical specifications of the steel making plant are described in Appendix A. Additionally, it should be noted that the chaotic model of the DC arc furnace as presented in Kolagar and Shoulaie and Kolagaret al has been employed in this paper. Moreover, the switching frequency of matrix converter has been taken into account equal to 600 Hz, and also the frequency of input and output side of the matrix converter has been selected equal to 50 Hz.…”

“…Table shows the average values of the input power factor in the matrix converter‐based power supply for CCC and CPC methods. From the results, it is found that the proposed feeding power supply leads to the highest power factor in comparison with the conventional ones and also has almost the same value compared with the PWM‐AC chopper‐based power supply …”

“…To evaluate the voltage flicker severity at the point of common coupling in the proposed power supply, the IEC flicker meter, which is briefly presented in Kolagar and Shoulaie, has been utilized in this paper. As it is known, P st represents the short‐term flicker severity index.…”

“…Heretofore, two types of feeding topologies have been applied for DC electric arc furnaces. The former one is established upon multipulse thyristor rectifiers, and the latter one is composed of multipulse diode rectifiers along with DC chopper modules . Although such feeding topologies may be used successfully in industrial plants, there are some noticeable drawbacks due to the nature of these topologies.…”