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A novel method of overvoltage suppression due to de-energization of shunt reactor in high voltage system Al-Tak, Mazyed A.; Ain, Mohd Fadzil Bin; Al-Yozbaky, Omar Sh.; Jamil, Mohamad Kamarol Mohd
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 14, No 4: December 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v14.i4.pp2134-2147

Abstract

Substations usually employ shunt reactors to reduce the reactive power of systems. Due to current chopping when the shunt reactor is shut off, a high frequency and amplitude overvoltage is generated. This study was aimed at eliminating switching-related overvoltages in shunt reactors so as to maintain the equipment, prevent insulation failure, and avoid reignition. Therefore, the circuit was modified according to the suggested mitigation strategy to verify that transient overvoltages are suppressed by the circuit breaker and shunt reactor. With a view to evaluate the existing chopping caused by the switching of reactor bank, the alternative transients program (ATP-Draw) model was used to simulate the transients resulting from switching a shunt reactor. This work has been put into practice for various current chopping values. The collected results of the simulation showed that the proposed model was significantly highlighted for the suppression of overvoltages, with the voltage across the circuit breaker being reduced from 679 KV to 478 KV at a current chopping value of 5 A and from 351 KV to 152 KV across the shunt reactor.
Impact of grading capacitor on transient recovery voltage due to shunt reactor de-energization for different values of current chopping Al-Tak, Mazyed A.; Ain, Mohd Fadzil; Al-Yozbaky, Omar Sh.; Jamil, Mohamad Kamarol Mohd
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 15, No 2: June 2024
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v15.i2.pp1300-1307

Abstract

This paper investigates the impact of grading capacitors on transient recovery voltage (TRV) during shunt reactor switching in high voltage systems, considering different levels of current chopping. Shunt reactor de-energization can result in voltage surges and instability due to current chopping effects. The study utilizes simulation models using ATP-Draw software to assess the effectiveness of grading capacitors in mitigating TRV under various operating conditions as well as of using a proposed method to mitigate the excessive TRV across the circuit breaker. The findings provide valuable insights into managing TRV during shunt reactor switching, enhancing power system stability and reliability. The results obtained showed that the TRV across the circuit breaker decreased by 61.5% by using circuit modification as well as adding a grading capacitor.
Effect of shunt reactor rating on the switching transients overvoltage in high voltage system Al-Tak, Mazyed A.; Ain, Mohd Fadzil; Al-Yozbaky, Omar Sh.; Mohd Jamil, Mohamad Kamarol
Bulletin of Electrical Engineering and Informatics Vol 13, No 1: February 2024
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v13i1.6100

Abstract

This paper includes a computer simulation of switching transient overvoltages during the disconnecting of shunt reactors (SR). Based on the results of the transient simulations, two reactors (150 MVAr and 50 MVAr) were examined. Reactor current interruption causes significant overvoltages, especially across the reactor and the circuit breaker (CB). The severity of these overvoltages may surpass the voltage level, which might endanger the reactor’s insulation and accelerate the CBs ageing process. For this reason, a significantly modified circuit model is proposed. The results of the field testing showed that the proposed modified circuit technique was successful. The transient overvoltages were computed using ATP-draw simulations of the equivalent circuit during switching. Successful synchronous switching could decrease the electromagnetic and mechanical stress generated during frequent switching operations. The model was examined the switching transient overvoltage for different values of current chopping (0-20) A. The proposed model proved that the reduction of the overvoltage was 86% in case of (50 MVAr) shunt reactor rating and 87% in case of (150 MVAr) shunt reactor rating.