Power system protection upgrade at anclote plant a case study in florida state

Power system protection coordination is essential for power system reliability and security. This paper focuses on the coordination analysis of the 480VAC system at Anclote plant located in the state of Florida. Due to the obsolete status of the existing trip units associated with the 480VAC power circuit breakers at Anclote plant along with the lack of inventory, in 2016, Duke Energy decided to replace all the varied 480VAC trip units with the Utility Relay Company (URC) AC-PRO® trip units in order to (1) reduce inventory and (2) incorporate a standard trip unit for the 480VAC system. The engineering analysis phase of this project was accomplished by Phasor Engineering and approved by Duke Energy in 2016. Phasor Engineering performed a comprehensive protection coordination study on the 480V trip units of the plant using the following two methods: (1) Sequence of Operation Analysis and (2) Time-Current Curve (TCC) Analysis. The electrical model of the power plant was developed and analyzed using Electrical Transient & Analysis Program (ETAP) software, version 14.1. We plan to present the highlights of this industrial project in two papers. In this paper, a big picture about the problem, case study, different configurations, the characteristics of the employed trip unit, and the adopted strategies to resolve mis-coordination is presented. In the next paper, using the fundamentals given in this paper, we will provide further details about the implementation of this project on all of the 480VAC power circuit breakers at Anclote plant.