Date of Award


Degree Name

Doctor of Philosophy


Electrical and Computer Engineering

First Advisor

Dr. Pablo Gomez

Second Advisor

Dr. Ikhlas Abdel-Qader

Third Advisor

Dr. Richard Meyer


transient analysis, frequency domain, kron reduction, network equivalents


Frequency domain (FD) methods for electromagnetic transient analysis of electric power systems offer outstanding simplicity and accuracy when dealing with distributed parameter elements and components that exhibit frequency-dependent behavior. However, the use of FD methods is usually restricted to the simulation of small and simple networks, since it is commonly believed that their application implies a very large computational burden when compared to time domain methods. This study demonstrates that FD methods can accommodate the detailed simulation of large distribution networks within acceptable computer times and in a very straightforward manner, thus offering an attractive complement or alternative to common time domain tools. For this purpose, the basic methodology and guidelines for the frequency domain modeling of the most common components of distribution systems are described in detail, as well as a general approach for network construction, reduction, and solution. The elements considered include overhead lines, underground cables, transformers, circuit breakers and loads. As an added advantage of FD methods, the application of network equivalent techniques for the reduction of large systems is considerably simpler than in time domain, as shown in this study. This is particularly valuable for the simulation of distribution systems given their size and complexity.

Initially, transmission line, underground cable, and transformer models are implemented separately for verification purposes. In addition, a simplified distribution network and a test feeder from IEEE (13-bus) are constructed to demonstrate that the network reduction technique does not imply any loss of accuracy, and it also provides very similar results when compared with the complete network implementation in Electromagnetic Transient Type Program-Alternative Transients Program (EMTP-ATP). Then, 3 test cases corresponding to larger distribution systems are simulated. They correspond to IEEE test feeders with 34 and 123 nodes and a synthetic system with 1188 nodes emulating a densely meshed urban distribution network. These cases demonstrate the generality of the methodology and the ability of the network reduction to simplify the system and efficiently reduce the computational burden in the simulation of large systems.

Access Setting

Dissertation-Open Access