| Summary: | The uncertainties faced by distribution network designers in meeting future load growth of an installation is briefly discussed. The study has looked into the effect of electrical design on the operational cost of a 22 kV university distribution network. Optimal networak configurations were determined for various phases of the campus project using a Loss-Minimising Algorithm (LMA). The technique uses the results of steady-state load flow simulation using SINPOW1, one of the power system packages available today. Secutiry analysis was also carried out using the same package to assess the capability of the feeder cables in the network during emergency. The effect of charging crurrent to the substations' voltages during the night due to the capacitive charging inherent in the underground cable was also investigated. Comparison of cable was lossed was carried out using the Present-worth Method between the planned and athe optimal networks. A similar method was used to evaluate the cost of transformer lossed in the proposed campus distribution network. As a result of this study, three alternatives were proposed to reduce the cost of transformer losses, one of which could possibly reduce the cost of losseds by as much as 40% in twenty years, the assumed life span of the trsnsformer. To the further reduce the operational cost of the campus, various alternatives for Demand-side Management (DSM) were also studied. An investment on the load-shifting of the air-conditioning load of the campus was found to be feasible. Various other to reduce the peak load MD were also briefly discussed. As new transformers are still being added to the network and the preference to the use of circuit breakers (MCCBs dn MCBs) over fuses in the LV circuits protection, the various levels of potential short circuit current in the network were determined. Fault simulations on the 22 kV portion of the network were carried out using fault calculation facility available in the SIMPOW package. Based on the fault levels obtained from the 22 kV simulations, the porspective fault currents on the LV section were calculated using Lotus 1-2-3 spreadsheet. The effect of changing the normal open (NOP) on the network to the fault level was also investigated.
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