Power Distribution in Lagos Metropolis: Assessment of 132kv Network Capacity

Abstract

In this study, Lagos power distribution network at sub-transmission voltage (132 kV) was modeled and assessed. This is very relevant for the planning of effective electricity supply to the economic capital. The expected power demand of the metropolis was determined and the normal mode parameters computed for numerical analysis. The study was done for two scenarios: unilateral and multilateral injection of power into the network, using matrix algebra of mode linear equations by current balance. Analyses of results show that the total capacity of existing 330 kV/132 kV injection sub-stations is 1.71 GVA. The apparent power required to feed Lagos metropolitan 132 kV network is about 2.5 GVA (at 0.89 power factor), when power is injected through all the 330kV/132 kV injection substations. However, power transferred in the network lines is only 0.93 GVA at 0.9 power factor and at 97.4% efficiency. The power transfer capacity of the132 kV network lines alone is adequate when all injection stations simultaneously supply electricity. Any condition (emergency or otherwise) allowing only unilateral in-feed option at 132 kV, will lead to inadmissible voltage drops and overload conditions of lines unless drastic load shedding measure is applied. The total capacity of 330 kV/132 kV injection substations is inadequate by about 0.74 GVA (29 %). The total power required cannot be met by existing local thermal station of about 1.32 GVA maximum; the generating capacity development of Lagos should be looked into critically.