Wide-area early warning systems are dependent on synchrophasor (PMU) data-based applications for providing timely information to operators so that preventive actions can be taken. This talk can be divided into two parts; i) the voltage instability detection and ii) the voltage instability mitigation. For the first part, there are two methods for preprocessing data; i) normal low-pass filtering and ii) linear regression before computing sensitivities for voltage stability monitoring. Some important electrical components such as Over Excitation limiter and On-Load Tap Changer which create discrete changes affecting in voltage instability have been included to assess the methods' performance. Moreover, both process and measurement noises, obtained from real-time hardware-in-the-loop simulation and real PMU measurements from the Norwegian network, respectively, have been applied to validate robustness of the proposed methods. For the second part, the talk describes some examples of how the synchrophasor can be utilized to coordinate with HVDC controls to steer power systems away from voltage instability conditions. The approach is used to ensure that HVDCs will operate securely when their transfer is pushed towards the maximum transferable power level.
Dr. Rujiroj Leelaruji is a Post-doctoral Research Fellow within the Electric Power Systems (EPS) research group at KTH. The main theme of his research is to develop methods for voltage stability assessment using PMUs data, including perform signal processing methods to extract unwanted dynamics and measurement errors from PMU data and improve visualization approach for wide-area voltage stability monitoring to be used in wide-area early warning systems. Rujiroj received the B.Sc. degree in Electrical Engineering from Sirindhorn International Institute of Technology (SIIT), Thailand, in 2004. He received his MS in 2007 and PhD in 2012, both in Electric Power Engineering from Royal Institute of technology (KTH), Stockholm, Sweden. His Ph.D. thesis was related to the implementation of algorithm for coordinating system protection and HVDC/FACTS controllers to determine preventive measures that will mitigate wide-area system collapse.