Sensitivity of a frequency scanning program to variations in system resistances

• Main Author: Butt, Robert Samuel, 1959-
• Other Authors: Schooley, Larry C.
• Language: en_US
• Published: The University of Arizona. 1988
• Subjects: Subsynchronous resonance.; Frequency response (Electrical engineering)
• Online Access: http://hdl.handle.net/10150/276657

Various computer programs are currently used by electric utilities to determine if potential subsynchronous resonance problems exist which can impact turbine-generators. One of the most popular of these is the frequency scanning program. The representative transmission system input data for these programs are generally based on constant temperature and frequency. However, as conductor temperatures and applied frequencies fluctuate, the resistances also change. This thesis investigates the effects that resistance variations, due to temperature and frequency, have on frequency scanning results. The maximum resistance change (increased and decreased) from the standard value is determined and applied to the transmission lines in four study system cases. The frequency scan output for the modified cases is used to determine if torsional interaction has become more severe. It is found that, under extreme conditions, the net system damping can decrease by over one hundred percent.