21-09-2008, 09:48 AM
Based on closed form expressions for the power frequency voltages and currents in a typical distribution network, the voltage regulation VR at any time point during the day could be evaluated. It will depend primarily on the network configuration, the daily load curve, the load density and its power factor as well as level of the reactive power compensation.
The computed at a certain time?t? can give a useful indicator for the voltage constancy over the network at that time point. The concept of ?Global Voltage Regulation? is introduced. The GVR is defined as the root mean square value of the voltage regulation over the daytime as ?t? varies from 0 to 24 h. Accordingly , it takes into account the effect of both the geometrical dimensions of the distribution network and the daily temporal variation of the voltage regulation .The theoretical value GVR =0 corresponds to the ideal case in which the voltage is constant at all nodes ,all the time. Hence GVR can be considered as a representative figure of merit describing the supply quality regarding the voltage values prevailing at the different network nodes, allover the day. The paper also addresses the identification of the optimal level of reactive power compensation (K) that will lead to the least possible GVR. Moreover the impact of both the network and load parameters on the optimal value of ?K? is investigated..
