Известия Томского политехнического университета: Инжиниринг георесурсов (Mar 2021)

INFLUENCE OF REACTIVE POWER COMPENSATION ON OVERVOLTAGES VALUE WHEN SWITCHING POWER TRANSFORMERS

  • Roman S. Kuzmin,
  • Artem A. Zavalov,
  • Roman A. Mainagashev,
  • Vitalii A. Menshikov,
  • Ilya S. Kuzmin

DOI
https://doi.org/10.18799/24131830/2021/3/3115
Journal volume & issue
Vol. 332, no. 3
pp. 197 – 209

Abstract

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The relevance of the research arises from the need to develop technical solutions to limit switching overvoltages that occur when switching power transformers and effective compensation of reactive power. The main aim of the research is to study the influence of reactive power compensation on value of switching overvoltages when switching power transformers 6 (10)/0,4 kV and substantiation of the most effective means of protecting power transformers from switching overvoltages. Objects: transformers with a rated power of 250, 400, 630 and 1000 kVA; vacuum circuit-breaker; individual phase compensation devices. Methods. Instrumental-oscillographic, simulation of transient processes of phase voltages was performed in MultiSim. Results. The authors have analyzed the efficiency of existing protection equipment against switching overvoltages arising during switching of power transformers 6 (10)/0,4 kV. Computer simulation of influence of reactive power compensation on switching overvoltage value was performed. To confirm the simulation results, experimental studies were performed. The oscillograms of switching overvoltages that occur when a power transformer with rated power of 250 kVA is disconnected are shown. It was established that devices designed for reactive power compensation can be successfully used to suppress switching overvoltages when switching power transformers, provided that, these devices are connected to the low voltage winding of the transformer. In residential electric networks for effective compensation of reactive power it is proposed to use capacitor units with individual phase compensation and to place them on the input bus of municipal and residential buildings. For suppression of switching overvoltages in residential electric networks, it is necessary to introduce a capacitor unit with symmetrical unregulated compensation at transformer substations.

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