A Model for Assessment of Power System Outages on Nigerian Transmission Network.

Abstract

------------------------------------------------------------ABSTRACT--------------------------------------------------------A power outage is a short or long-term loss of the electric power to an area such as faults at power stations, damage to electric transmission lines, substation or other parts of the power system.The Nigerian national grid is characterized by frequent outages due to aging of equipment/ lines leading to frequent conductor jumper cuts, frequent earth faults resulting from reduction in overhead clearance and refuse burning and circuit breaker problems. This paper develops a polynomial model for the assessment of power system outages on the Nigerian transmission network using curve fitting tools analysis. Data from the transmission network of the national grid were collected and used as input parameters for the computation of the statistical parameters to develop the power system outage model for the network. The results of the work showed that the statistical mean and median of the total outages were 73.11and 203.50 respectively even though February was the modal month with an outage of 373 due to frequent interruptions experienced by customers during this month. Forced outages on the transmission network recorded the highest value of 44.8% while 32.5% were due to urgent outages and 22.7% were due to planned outages suggesting that the resistance of the network is very low resulting in very low efficiency and disruption in the lives of the citizenry. The result of the work also showed that the polynomial model developed for the assessment of the power system outages is of order 5 whose order increases as more outages are recorded on the transmission network. Ageing of equipment, lightning, vandalization and poor maintenance culture have been identified as some of the causes of power outages on the transmission network. The analysis of the paper can be used to emphasize that in order to ensure safety and security of the transmission network, there is the need for a proper protection of the transmission lines system.