Analysis of the electrical frequency in Caracas during four major events of the year 2008

This article presents an analysis of the behavior of the electrical frequency in Caracas during four major events of the year 2008. The frequency was computed from the voltage signals of the fault recorders. The events of April 29 and September 01 were faults in transmission lines of the National Grid, and the event of October 19 was the erratic trip of two main lines at 765kV (Guri-Malena). In these events, the frequency evolution caused the trip of the islanding scheme of the Caracas´ electric utility (EDC), but later EDC collapsed. The event of December 11 was the erratic operation of the islanding scheme of EDC, and the underfrequency load shedding avoided a total collapse of EDC. The analysis of these events has been useful to do the corresponding recommendations.