Impact of customer load characteristics on voltage stability assessment in smart grids using synchrophasor measurements

Abstract

The major cause of some recent blackouts around the world has been attributed to the heavy loading conditions compounded by the lack of real-time measurements and tools required for effectively monitoring these load conditions and their characteristics. The existing Supervisory Control and Data Acquisition (SCADA)/Energy Management System (EMS) platforms are usually based on unsynchronized SCADA measurements with a slow reporting rate of 1 measurement every 2–10 seconds. Synchrophasor measurements from Phasor Measurement Units (PMUs) are increasingly being used to replace SCADA measurements because they are time-synchronized and can have a reporting rate of up to 240 measurements every second. This paper investigates the impact of customer load modelling, load composition, and load characteristics on power system voltage stability using real-time synchrophasor measurements obtained from PMUs. Voltage stability assessment indices are applied in this investigation in order to accurately determine the power system's transfer limits and reduce the system's operational uncertainties. Results for four case studies carried out using the 10-bus multimachine benchmark test system and a ‘proof-of-concept’ testbed are presented. The testbed is implemented using industrial-grade equipment comprising of the Real-Time Digital Simulator (RTDS), PMUs, Phasor Data Concentrators (PDCs), Programmable Logic Controller (PLC), communication network switches, and GPS satellite clock.