A performance assessment of the distribution subsystem in the deregulated Nigerian power sector

Persistent under-performance of the Nigerian power industry after its deregulation shows that the unbundling of the sector has not taken the industry to the envisaged level. It is claimed that the distribution companies have been operating at the mercy of the upstream operators as the performance efficiencies of the former are limited by some operational constraints inherent in the latter. This paper examines the ill-performance of the industry from the standpoint of whether or not the downstream consequences of some operational deficiencies of the upstream operators, particularly the transmission company, are the major trauma bedeviling the distribution companies. Details of the causes of power outages on a total of 81 injection feeders of a distribution network, over a period spanning through 33 months, are acquired from the monitoring Regional Control Centre. The causative factors of the outages are categorized into two: transmission constraints attributed factors (TCAFs) and distribution constraints attributed factors (DCAFs); and the two compared based on the frequency of occurrence. A total of 32,347 power outages are recorded on the network during the period under study, while the most frequently occurring cause of the outages is found to be earth fault. It is also revealed from the analysis that the power outages are predominantly (99.86%) instigated by inherent deficiencies of the distribution facilities rather than operational constraints on the part of the transmission infrastructures.