ISSN E 2409-2770
ISSN P 2521-2419

Utilization of Under Frequency Load Shedding (UFLS) and Under Voltage Load Shedding (UVLS) Schemes in Improving Voltage Level at Injection Substations

Vol. 4, Issue 5, PP. 60-66, May 2017


Keywords: Frequency, load shedding, under voltage, power distribution, substation

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Optimizing load shedding (LS) in developing country has become a major control challenge facing the power distribution companies today resulting from poor generation to losses of power via the transmission lines and theft of energy at the distribution levels. This paper deals with LS issue posed on the utility providers, most load shedding scheme proposed so far used either voltage or frequency parameters known as under frequency voltage load shedding (UFLS) by this it means in a situation where frequency is 50 ± 0.25 Hz the utility provider will no longer ahead to the stipulated laws governing the frequency and for the under voltage load shedding (UVLS) scheme the percentage voltage drop which is + or - 6% in line with International Electrotechenical Commission (IEC 60038) will be violated, in this paper both (UFLS) and (UVLS) indices were used in achieving a more comprehensive, effective, and reliable load shedding strategy from the result analysis of the network which comprise of three feeders and sixty-three substation using ETAP 12.6 in running the load flow analysis, it was very clear that all buses in service as at the time of this analysis violated the percentage voltage drop but with the exception of a particular substation which also doubles at point load which was within the percentage voltage drop both at peak period and off peak period of the day with the combination of both method UFLS and UVLS the substation which were outside the acceptable voltage and frequency range were now operate within the stipulated rule also the substations on the distribution network (Feeder) were automated to drop or pick load on its own without any human interference the system.

  1. Emmanuel Ighodalo OKHUELEIGBE,, Department of Electrical /Electronic Engineering, Federal University of Petroleum Resources Effurun, Delta State, Nigeria.
  2. Joseph Ailenokhuoria OGBEKHIULU,, Department of Electrical /Electronic Engineering, Federal University of Petroleum Resources Effurun, Delta State, Nigeria.

Emmanuel Ighodalo OKHUELEIGBE Joseph Ailenokhuoria OGBEKHIULU

  1. [1]     Onohaebi O. Sunday, ”Darknes;/s at Sunrise in Nigeria Illuminating the dark sport Before Sunset” Inaugural Lecture Series 146 University of Benin, 16th  October, 2014.
  2. [2]     NIPP daily broadcast, accessed 5th August, 2014.
  3. [3]     Information on factbook/geos/ni.html
  4. [4]     Information on
  5. [5]     Balogun, A.Z. 2010. “The Impact of Domestic Natural Gas Pricing on Electricity Tariffs in Nigeria” IEEE ICSET 6th-9th December, 2010.
  6. [6]     Presidential Task Force on Power, 2011.
  7. [7]     Information on
  8. [8]     Information on
  9. [9]     Shah N., Abed A., Thomas C., Seabrook J., Pereira L., Kreipe M., Mavis S., and Green T., Final report of UVLS task force: under voltage load shedding guidelines", Western Systems Coordinating Council, 1999.  Sri Lanka.
  10. [10]  Min Y., Hong S.B., Han Y.D., Gao Y.K., Wang   Y., Analysis of power-frequency dynamics and designation of under frequency load shedding scheme in large scale multi-machine power systems", IEE International Conference on Advance Power System Control, Operation and Management, Vol. 2, pp. 871-876, 2013.
  11. [11]  Arulampalam A., Saha T.K., “Fast and adaptive under frequency load shedding and   restoration technique using rate of change of frequency to prevent blackouts", IEEE Power and Energy Society General Meeting, Vol. 1, pp. 1-8, 2010.
  12. [12]  Ding Z., Cartes D., Sirvastava S., “New load shedding scheme for islanded power systems"    IEEE/SMC International Conference of Systems Engineering, Vol. 1, pp. 1-6, 2006. Educational, Scientific and Cultural Organisation -ISESCO 1426 A.H.  2005.
  13. [13]  E.I. Okhueleigbe (2016). Enhancing Power Distribution Network using Distributed Flexible Alternating Current Transmission System (D-FACTS) Devices, P.hD Thesis University of Benin, Benin City, Edo State, Nigeria.
  14. [14]  International Electrotechenical Commission (IEC 60038).