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

Overview & Synopsis

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.