A modified linear contribution factor model for improvement of relability indices of electrical distribution systems.

Abstract

In Nigeria, satisfactory degree of reliability has not been attained in our power systems in recent times. The average duration of interruptions that customers experience is quite high and the degree varies from place to place. This is evident all around the nation, most especially in urban commercial cities. Previous researchers have focused on assessment of power system reliability indices using different models. In this work, a computationally efficient 'modified linear contribution factor model (LCFM) is developed. The model can be used for appreciable improvement of all the major system reliability indices of practical distribution systems unlike the conventional LCF model which can only improve some of the system reliability indices of practical distribution systems. Data collection and data analysis were carried out to develop the LCF model used on the three selected distribution systems on the Nigerian National Grid. The results 'of this work indicates that part of the reliability indices computed for the distribution systems SAIFI is more sensitive to the LCF model than SAIDI and CAIDI but that the sensitivity is low for SAIDI index compared to CAIDI. This is due to the quantization of the annual number of customer interruptions caused by the type and placement of protective devices on the distribution systems of the National Grid. With the use of the modified LCF model, the average percentage improvement in the system reliability indices become 97.72%. 98.55% and 98.63% for Ibadan, Ilorin and Ikeja distribution systems respectively as against an average percentage improvement of 36.08%. 11.36% and 24.36% in the system reliability indices for Ibadan, Ilorin and Ikeja distribution systems respectively with the use of conventional LCF model. The result of this research work confirms the efficiency of the modified LCF model.