June 16, 2002
June 16, 2002
June 19, 2002
7.926.1 - 7.926.7
Power Distribution System Conductor Sizing as Viewed From Thermodynamics Principles
Ilya Grinberg, Petro Gogolyuk, Taras Grechyn
Buffalo State College/ L’viv Polytechnic National University
The task of educating members of an engineering team (engineers, engineering technologists, and engineering technicians) becomes even more challenging as technology evolves towards new horizons. Power electronics, robotics, networks, advances in manufacturing technologies as well as environmental and energy saving concerns call for new pedagogical and curriculum development approaches. Theoretical instructions, laboratory exercises, and projects should include emerging issues and be common to several disciplines across the curriculum. One of the topics of such integration is identifying and linking related issues in electrical engineering/electrical engineering technology and thermodynamics courses. An example of such a topic is sizing conductors based on their current carrying capacity as well as fault current calculations.
Power distribution systems for industrial facilities with voltages less than 1 kV are decisive in terms of systems’ reliability, voltage quality, energy savings, and electromagnetic compatibility among others. In such systems only fuses or automatic (molded case) circuit breakers are used to protect from overcurrents and faults unlike more sophisticated protection techniques in systems rated over 1 kV. Such thermal protection units have varying characteristics and could differ from unit to unit quite significantly. Therefore, conductors at this voltage level should be checked not only for rated continuous current carrying capacity (ampacity) but also for their thermal stability. Thermal stability calculations involve solving for conductors’ temperature at the end of the fault clearing process. Maximum allowable temperatures depend on insulation properties and are defined by the National Electrical Code © (NEC) 1
This paper derives formulas to determine time-current characteristics of conductors to be used in coordination studies related to protective devices. The results are used in corresponding energy courses (electrical and thermodynamics) as well as in student projects.
2. Conductor Selection Based on Short-Circuit Current Temperature Rise
According to the NEC® conductors are selected based on the following conditions:
Proceedings of the 2002 American Society for Engineering Education Annual Conference & Exposition Copyright © 2002, American Society of Engineering Education
Grechyn, T., & Gogolyuk, P., & Grinberg, I. (2002, June), Power Distribution System Conductor Sizing As Viewed From Thermodynamics Principles Paper presented at 2002 Annual Conference, Montreal, Canada. 10.18260/1-2--11345
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