Improving power system stability of South Africa's HVAC network using strategic placement of HVDC links

In this paper an investigation was carried out to determine the effects that HVDC schemes have on the machine rotor angle transient stability. The study was carried out on a detailed model of South Africa's main transmission system (MTS). A focus area consisting of an existing power station, a power station under construction, two planned power stations and existing and planned substations as well as the transmission lines making up the Limpo-West power transmission corridor was used for analysis. The network was modelled in DIgSILENT PowerFactory software. Two scenarios; the network without an HVDC scheme and the network with a HVDC scheme imbedded in it were analysed and the obtained results were compared. The results show that when an HVDC scheme is imbedded into the network in parallel…