Determination of the maximum number of ASVT sub-stations that can be terminated on 132Kv line without voltage profile violation

Abstract

In developing countries, there are many high voltage transmission lines which transverse villages not supplied with electricity to supply main towns and industrial areas. The conventional substations are too expensive and the power distributor can only set them up if return on investment is assured. Non-conventional (ASVT) sub-stations have been tried and found to be technically successful in stepping down 132kv to low voltages like 240volts in one step to supply single phase loads. Though this technology is cheap and technically fit to be applied in areas of low demand were setting up conventional sub-station will be uneconomical, the technology is not fast spreading in SubSahara Africa (SSA) where there are well established transmission line but poor distribution network. More so the technology remains as a pilot project in countries like Congo were they were first tried. This research aimed at investigating whether violation of voltage profile of the transmission line could have led to low spread of ASVT sub-station technology in Sub-Sahara Africa. The investigation of the maximum number of ASVT substations which could be terminated on 132kv line to supply these villages with electricity without voltage profile violation was carried out. In this research, transmission line and ASVT substation models were implemented using SIMULINK software in MATLAB environment. Surge impedance curves were also used to identify the point of voltage instability or voltage collapse in the system.