Effects of Harmonic Distortions Emanating from Domestic Loads on Low Voltage Installations Low Voltage Switchgears: Case Study

  • C Ndungu Jomo Kenyatta University of Agriculture and Technology, Juja, Kenya
  • J Nderitu Jomo Kenyatta University of Agriculture & Technology, Juja,Kenya
  • L Ngoo Multimedia University of Kenya
  • P Hinga Multimedia University, Kenya
Keywords: Distribution transformer, total harmonic distortions

Abstract

Application of loads such as computing devices, mobile chargers, audio-visual, air conditioner and energy saving bulbs like Compact Fluorescent Lamps (CFLs) at domestic power end users has resulted in the increase of harmonic distortions in low voltage network. The main difference between domestic loads of today and that of few decades ago is penetration of electronic appliances with Switch Mode Power Supply (SMPS). These appliances are rapidly increasing due to technology advancement of semiconductor devices and digital controllers. The presence of harmonic distortions have adverse effects on low voltage network installed switchgears such as premature loss of distribution transformers, over-loading of neutral conductor and heating of reactive compensating feeder capacitors. In recent time, loss of distribution transformers prematurely has contributed to myriad outcry of power users and high cost of operational and maintenance (O&M) costs to power utilities. The business daily of May 2017 showed that the residential loads constitute up-to 75% of the total connected loads in Kenya (4.4 million) power end users are in the category of domestic consumers. In this regards, their effects on power system cannot be ignored/ assumed. This study investigated the level of current harmonic distortions of modern domestic appliances and harmonic levels at distribution transformers and the impact they have on distribution transformers. It was found out that current harmonic distortions were significantly higher than permissible levels at point of common coupling. The third current harmonic was found to be the most dominant harmonic order at secondary side of the distribution transformers. Worth mentioning is that Total Current Harmonic Distortions (THDi) was low when various loads were supplied together due to damping effects vis-à-vis harmonic generated by TV alone- CRO-type. It is recommended that mitigation of current harmonics using active power filter to be done at point of common coupling (PCC) to reduce the negative impact of harmonic distortions on low voltage installed switchgears.

Article Views and Downloands Counter


Download data is not yet available.

References

Jyotirmaya, G., & Chinmay, D. (2014). Failure of transformers due to harmonic loads. International Journal of Electrical, Electronic and Mechanical Controls, 3, 11-16.

Haroon, F., Chengke, Z., & Mohamed, E. F. (2012). Analysing the harmonic distortions in a distribution system caused by the non-linear residential loads. International Journal of Smart Grid and Clean Energy, 3, 16-21.

IEEE C57.125. (2014). A standard guide for investigating failure, deformation and analysis for power transformer and shunt reactors. http://ieeexplore.ieee.org/ document/6905702/

Hussein, A. K (2013). Harmonic mitigation technique applied to power distribution network. Journal Advance in Power Electronics, 2, 17-24.

Mohammed, A. R. U., Mohammed, M., & Khaja, M. S. (2013). Failure analysis of power transformers. International Journal of Emerging Technology and Advanced Engineering, 9, 24-30.

Ndungu, C., Nderu, J., Ngoo, L., & Hinga, P. (2017). A Study of the root causes of high failure rate of distribution transformer - a case study. International Journal Engineering and Science, 2, 14-18.

Patel, M. N. S., Parsh, S., Maulik, D., & Nishish, B. (2015). Case studies of the transformers failure analyses. International Journal of Science & Research, 2, 5-10.

Shayan, T. J., Raheel, A. & Akif, Z. K. (2015). Transformer failures, causes and impact. International Conference Data Mining, Civil & Mechanical Engineering, 3, 51-57.

Singh, R., Zadgaonker, A. S., & Amarjit, S. (2014). Premature failure of distribution transformer - a case study. International Journal of Science & Research, 5, 18-23.

Published
2018-06-19
How to Cite
Ndungu, C., Nderitu, J., Ngoo, L., & Hinga, P. (2018). Effects of Harmonic Distortions Emanating from Domestic Loads on Low Voltage Installations Low Voltage Switchgears: Case Study. Africa Journal of Technical and Vocational Education and Training, 3(1), 214-222. https://doi.org/10.69641/afritvet.2018.3174