Line-limit-preserving power system equivalents

This dissertation develops methods to create power system equivalents that preserve thermal line limits. Existing equivalent methods do not retain thermal limits of equivalent lines, which may result in the transfer capability of the equivalent case differing significantly from that of the original case. Hence, power system equivalents have not been used for studies regarding line limits such as optimal power flow, security constrained optimal power flow, etc. However, recently there has been a need to create limit-preserving equivalents (LPEs) for studying power markets and environmental issues. Therefore, the goal of this research has been to assign meaningful values to equivalent line limits instead of a zero or infinity, which have been used in the industry. Three methods are presented to develop LPEs based on total transfer capability and available transfer capability. They are able to determine if a single bus or group of buses to be equivalenced has an exact solution. If it has an exact solution, equivalent line limits are assigned with little computation. In case of non-exact solution, three algorithms are capable of providing under-, best, and overestimates of equivalent line limits which can be used for different applications. Each algorithm has distinctive advantages and disadvantages and they are described in detail. All three algorithms are applied to various cases and the results are compared to show the differences. With the development of these methods, the use of equivalents will increase in various studies of power systems.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2017

Author dc:creator

• Jang, Wonhyeok

Contributors dc:contributor

• Zhu, Hao
• Overbye, Thomas J.
• Sauer, Peter W.
• Chen, Deming
• Bose, Subhonmesh

• Power system equivalent
• Ward equivalent
• Line limit
• Transfer capability

Statement dc:rights

• Copyright 2017 Wonhyeok Jang

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/97426

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/97426