Wide Area Synchronization Functionality
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Electric power engineering (MPEPO), MSc
Publicerad
2024
Författare
Mohamed, Abdin
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Abstract
Large interconnected power systems are constantly exposed to unpredictable disturbances that may often lead to system splits. This creates two or more synchronous areas where some end up with generation surplus and the others with generation deficit, and corresponding frequency deviations, which in most cases results in load shedding. Afterwards when the subsystems stabilize, the tricky part comes when its time for resynchronization since the systems are large compared to a small area. This thesis presents a development and testing of a phasor measurement unit (PMU)- based method with the aid of Wide Area Measurement Systems (WAMS) which introduces an immediate solution for the issue of stabilization and synchronization of subsystems. PMU sensors are fast, real time-stamped accurate devices linked to the Global Positioning System (GPS) that measure synchrophasors at various points on the grid, which would help transmission system operators (TSOs) to react and counteract any event or disturbance that might threaten the system. The research employs PSS/E software to perform static and dynamic load flow analysis on the Nordic power system when a disturbance occurred in the system that led into splitting to two synchronous areas. During the resynchronization process, two methods were evaluated: the conventional method (sequential reconnection) characterized by limited data gathering and communication delays between TSOs, and the developed method (simultaneous reconnection) that leverages the use of PMUs for reconnection of the lines, hence the system’s response was observed. Synchronization data that include frequency, voltage and phase angle differences from the subsystems, which were output, analyzed and compared for both methods. The results demonstrate that the simultaneous reconnection utilizing PMU sensors which provided real-time data that enabled TSOs to identify the lines that were tripped due to the disturbance created hence discovering the disturbance location and mitigate around the area of the split, as rapid as possible. In addition, the system downtime and the risk of further instability is reduced. This method added more to the understanding of the sequential reconnection method which is currently used for the resynchronization of subsystems while showcasing the benefits the simultaneous method when it comes to reconnection. Most likely in the near future the simultaneous method will replace the sequential reconnection method when more renewable energy sources are integrated.
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Ämne/nyckelord
Keywords: interconnected power systems, WAMS, PMUs, sequential resynchroinzation, simultaneous resynchronization, communication delays.