Optimal PQ Monitor Allocation for Voltage Sags Indices Calculation

This article presents a methodology for optimal PQ-monitor allocation and voltage sag estimation in distribution systems. The location of the PQ-monitors is carried out so that all the occurrences of voltage sags due to faults are observed by at least one of the monitors. The methodology is based on faults simulations considering the case of less severe short-circuit to allow recording of voltage sags generated by faults with equal or more severe short-circuit conditions. To estimate the sags in the non-monitored nodes, a database of voltage sags is used, where the scenario that best approximates the states of the monitored nodes is found in order to assign state values to the non-monitored buses. The proposed methodology was applied to the IEEE 34 node test feeder. The results show that the monitor location method is able to satisfactorily record and estimate all voltage sag events.