Unification of angle and magnitude stability to investigate voltage stability of large-scale power system
Description
The purpose of this investigation is to determine and to detect signs and patterns of power system dynamic behaviors that lead to voltage instability long before approaching the point of system voltage collapse In large scale power systems, voltage instability or voltage collapse is known to be a 'slowly' occurring phenomenon that result when power systems operate very close to their transmission line operating limits, are forced to transmit power over along distance, or the system has insufficient static and dynamic reactive power. Because causes of voltage instability are variations in load demand, P-V or V-Q curves of certain buses or the entire system constitute the basis of voltage instability scenarios. Although voltage collapse is thought of involving dynamic variation of 'voltage magnitudes', to certain degrees, they also include changes in 'voltage angles' from their transient stable equilibrium points. Most voltage collapses in large-scale power systems include a combination of 'voltage Angle' and 'Voltage Magnitude' changes, and under heavy loading of the systems, it is hard to decouple the two system behaviors from each other In this investigation, we use system models that are suitable for real-time simulation and observe dynamic behavior of power systems in response to changes in system loading, application of transmission system contingencies and disturbances, and change in the mixture and availability of static and dynamic reactive power availability in the system. Using the proposed system changes as system stimulus, we observe and record dynamic behavior of the system in both time and frequency domains. Methods of artificial intelligence, pattern recognition, template analysis, frequency spectrum analysis, eigen value analysis, time response, and traditional P-V and V-Q methodologies are used in our modeling, simulation, and analysis of power systems To simulate small and large-scale systems, we use EMTP/SGI real time simulation capabilities. The effort is conducted using complementary real time simulation capabilities of Tulane University and Entergy Services, Inc. In addition to 10-Bus test system, we will simulate a 39-Bus test systems and a real-size transmission system that is created based from Entergy's transmission system