Threshold-based monitoring of cascading outages with PMUs

Date: 11:00am, October 20, 2017
Location: CEPSR 414
Speaker: Dr. Atena Darvishi, New York Power Authority  

Abstract: When power grids are heavily stressed with a bulk power transfer, it is useful to have a fast indication of the increased stress when multiple line outages occur. Reducing the bulk power transfer when the outages are severe could forestall further cascading of the outages. Phasor measurement units (PMUs) are vital elements for monitoring and control of these heavily stressed power systems. This presentation demonstrates a new approach to implement and utilize PMU information to monitor operational transfer capability and limits based on voltage phasor angles with respect to thermal limits of transmission lines. The algorithm used for this new approach obtains thresholds based on the angle and then quickly deploys PMU data to monitor stress changes due to single and multiple outages in real time to send fast notification of emergency situations. The algorithm then calculates the area angle thresholds and later in real time, monitoring of the area angle and comparing it to the thresholds after multiple outages determines the urgency (or not) of actions to reduce the bulk transfer of power through the area. Area angle uses the topology and the synchronized measurements of angles across an area of power system to measure stress caused by outages within the area. The proposed algorithm is easy, quick and computationally suitable for real systems to capture bulk stress caused by outages and also to identify local stress. This presentation explores the idea of area angle in a Japanese test system and then it further investigates the relation between area angle to area susceptance and supports the findings in two areas of the Western North American power system. Finally, procedures will be developed to determine thresholds for the area angle that relate to the maximum power that can be transferred through the area until a line limit is reached. The procedure also identifies exceptional cases in which separate actions to resolve local power distribution problems are needed. The findings are supported by testing on a 1553 bus reduced model of the Western interconnection power system. 

Biography: Atena Darvishi is a power system engineering professional with more than 5 years of research work experience. Atena is currently working in research and technology development department at New York Power Authority (NYPA) where she has been involved in developing innovative techniques to enhance NYPA/ New York State power systems. Research and technology development group at NYPA is collaborating with external research and development organizations, academia, vendors and consultants to develop, implement, test and evaluate new tools and techniques for NYPA/ New York State. Atena has been working on several interesting projects including wide area monitoring and control using Phasor Measurement Units (PMUs), state estimator for operational use of synchrophasor management systems, cloud data sharing platform, evaluation and demonstration of dynamic line rating technology, pattern recognition techniques for monitoring using online infrared camera, hurricane resilience enhancement of transmission line system using multi-dimensional fragility model and so on.

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