T&D World Magazine

Liz Pratico: Looking for a Challenge

Liz Pratico has been searching for challenges all of her life. She enjoyed the challenge of solving technical problems in high school, so that is when she decided to become an engineer.

“I wanted to have a career that actually used all those mathematical concepts that most people groan about,” she said.

As a principal engineer in GE’s Energy Applications and Systems Engineering Group, she is still facing and solving complex problems. If anything is a challenge in the power industry, it is surge analysis. Pratico teaches Surge Analysis and Equipment Application, a Power Systems Education Course at GE Energy. The next class will be Aug. 18-20, in Schenectady, New York.

“Analysis of surges in the system is an important aspect of system planning. Many times, utilities view surge analysis as an afterthought that follows the planning of new projects,” Pratico said. “In addition to power flow, stability, and short circuit analysis that are typically considered during the planning process, the evaluation of electromagnetic transients can also impact the feasibility of certain project design aspects.”

The surge analysis course will cover the nature of switching and lightning surges, methods of overvoltage control and protection, and coordination of overvoltages with equipment insulation, in order to make equipment application decisions to ensure safe and reliable design. Participants will acquire knowledge and skills to quantify transient voltage stresses from the electrical environment.

“It is important to understand how equipment is selected and applied to control overvoltages due to lightning and switching surges--and also to withstand temporary overvoltages,” Pratico said. “Insulation coordination takes many types of system disturbances into account. By analyzing the system stresses and equipment insulation strength, the proper equipment can be applied to operate the system safely and reliably.”

Pratico pulls from extensive, varied experiences to teach her classes. After graduating from Florida Institute of Technology, she started out as an electrical engineer with NASA at the Kennedy Space Center where she tested scientific payload experiments to prepare them for a successful mission on the space shuttle. Her team simulated the orbiter systems to supply interfaces for the payload experiments, and she provided power systems support. She also developed software to process telemetry from the experiments for orbiter integration.

“Although this job in ‘rocket science’ near the beach was really cool, I wanted to return to upstate New York with a job where I could actually apply those differential equations to solve some other challenging problems,” she said. “This brought me to GE, where I began working as a power systems engineer in the Power Systems Engineering Department (now known as Energy Applications and Systems Engineering), which has a long history of noteworthy engineers that have shaped the development of the power industry.”

Pratico joined GE in 1991 and learned to analyze electromagnetic transients hands-on in GE’s Transient Network Analyzer (TNA) facility. She performed studies using miniature analog models to simulate power system switching events and evaluate their effects. GE’s TNA has a history dating back to the 1930s, and it evolved into a state-of-the-art facility of its time to evaluate significant transmission additions as grids developed in the United States and around the world. Gradually, with advances in computers, utilities were becoming more interested in digital programs used for this purpose.

The TNA experience gave her a good basis to begin performing these studies using the ElectroMagnetic Transients Program (EMTP).

“An abundance of study work over the years and the vast expertise of many gurus in the group provided me with a wealth of experience in electromagnetic transients and equipment application, as well as harmonic analysis, filter design, HVDC, and controls,” Pratico said. “When I was working on my Masters at RPI, I also had the good fortune to be a ‘Surge Phenomena’ student of Dr. Allan Greenwood, who literally wrote the book on electrical transients. So it is with this background that I am happy to teach Surge Analysis and Equipment Application to others.”

Pratico has been teaching the surge analysis course for eight years, but has continually been performing studies to help solve a variety of complex power system problems for utilities. Many involved modeling a portion of the power system, simulating pertinent system disturbances, and recommending equipment and operational guidance. In one recent example, she was a key contributor to an extensive set of studies that evaluated electromagnetic transients and dynamic overvoltages for the design of a challenging 345 kV cable project.

She is also currently working on the next installation of GE’s Variable Frequency Transformer (VFT), which is a rotating machine that controls power flow between two asynchronous grids. She recently commissioned several Torsional Stress Relays (TSRs) that are used to protect turbine-generators from shaft damage that can result from sub-synchronous resonance.

She said the best parts of her job are the variety of interesting and challenging projects and the great people she works with. “There is always something new to get involved in, such as renewable energy technologies, and something new to learn from the many experts in the group,” she said.

Pratico enjoys a good challenge in play as well. She spends her spare time in the outdoor with her family: hiking, boating and skiing. She also competes in triathlons. “I use the word ‘competing’ loosely, but running, biking, and swimming have always been favorites, and the test of physical and mental endurance and the collective support of all the participants make it a rewarding experience,” she said.

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