Protection Coordination Study of a 4.16kV International Airport Power Distribution Network Using Genetic Algorithm
Rousseller M. Landicho, Michael C. Pacis · 2023
The science in coordination study is the assurance of selectivity from each Overcurrent Protective Device (OCPD) which is well documented and discussed in many good textbooks and respectable publications, while the art is the implementation of the science which are the specified OCPD settings that vary depending on the engineer's experience. The artistic part is not bad for it promotes creativity and critical thinking; however, in a fast-changing world that necessitates process improvement for efficiency in doing business, a baseline setting is advantageous for engineers to work on and to finalize their recommended OCPD settings in no time. The “personality factor” can now be eliminated which was observed in the review process of 17 studies performed by MSERV in 2019. This improvement can be done by automating the coordination study instead of the manual process. The Genetic Algorithm (GA) is a widely used optimization technique for coordinating OCPD settings. In this research practicum, the GA is proposed to be included in the OCPD coordination study process, specifically the coordination of overcurrent relays (OCR). The airport's 4.16kV distribution system with 50 OCRs is modeled on Electrical Transient Analyzer Program (ETAP) as a test case. A coordination matrix is assembled, and the optimization of the time dial settings is performed on MATLAB using the Genetic Algorithm (GA) function. The resulting Time Dials (TD) yield coordination time intervals (CTI) that are 100% compliant with the operating time constraints of 0.3s and setting range boundaries from 0.01 to 1. The TD results were validated using a T-test with 3.9826 t Statistics versus 2.0017 critical values that suggested significant variation of GA with manual coordination. Further validation is made through the comparison of the ga results with Non-linear Programing (fmincon) and Patten Search (patternsearch) which results in the same TD values up to the hundredth decimal place, the implementable setting range of the OCR, justifying the GA application. The time-current characteristic curves (TCCs) are also inspected to occupy in between the operating and damaged region of electrical equipment to ensure sufficient protection of electrical equipment.