Power demand and supply allocation using inherent structural theory of network systems and voltage stability index based on multi-bus reactive power loading.

Abstract

Power availability is a crucial factor in determining new load centers. There is a need for adequate power reserve and maximum load capacity allocation to ensure continued power demand and supply electrical systems. In modern interconnected power systems, a high peak load power demand is met by the contribution of the available generator units. There is an urgency to solve the challenges arising from interconnected network configurations such as the loss of generation, inadequate supply capacity to meet load demand during peak time, transmission losses and significant voltage drop at the heavily loaded buses. This dissertation investigates the influence of inter-connected load buses on the system’s voltage profile and the electrical proximity from generation sites to load centers as captured by the Y-admittance matrix. The inherent structural theory of networks was used in determining the required power reserve and load capacity allocation using the ideal generator contribution index. PowerWorld simulator, Dig SILENT Power Factory and MATLAB were used as simulation and presentation tools for the modified IEEE 14 bus system and the Southern Indian 10 bus system. From the analysis of the results, much of the load capacity needed for electrical load growth is feasible for the bus that is most electrically proximal to a high-rated power source. The use of the ideal generator contribution index exploits the structural properties of the network. That being the case, its advantages include minimum expansion of existing structures and minimal transmission active power losses. Also, in this dissertation, a V-Q curve characteristic approach was used to identify the weak load buses in an interconnected power system. This was done by simulating uniformly distributed multi-bus loading conditions and the conventional analysis of the sole bus loading method in a power network system up to the minimum acceptable per unit voltage point. This lead to the formulation of a novel V-Q curve-based index. The voltage critical multi-bus index is a variable state-based index. This index was compared with the self-sensitivity index of the reduced Jacobian matrix and the ‘load structural electrical attraction region’ index of the inherent structural theory of power networks, giving a deeper insight into the system characteristics under light and heavy loading states.