Load Model Identification Using Portable PMUS: A Case Study in the Omani Transmission System

This paper presents a measurement-based load modelling approach. The approach uses portable Phasor Measurement Unit (PMU) devices that can be rapidly installed at substations. These PMUs use GPRS communication to send data to a Phasor Data Concentrator (PDC). Two PMUs are installed at each monitored station. One PMU is installed at the low-voltage side of the supply transformer while the other PMU is installed on a selected substation outgoing feeder. Disturbances are continuously monitored by these devices. A measurement-campaign of at least 6 months is typically required to capture enough data to characterize the load dynamics and load behaviour. To this purpose, voltage disturbances are filtered out and extracted from the measurement campaign data. Each relevant voltage disturbance is “replayed” off-line using a simulation software to identify the most likely aggregated load model at the monitored feeder/substation. The load model identification methodology produces representative load models for system planning applications. This method provides added value to transmission operators as a better and more realistic representation of load model will aid planning engineers to adequately assess dynamic voltage stability.