Benchmark Systems for Digital Computer Simulation of a Static Transfer Switch

Safe-triggering-region control scheme for suppressing cross current in static transfer switch

“…Therefore, the larger the cross current threshold selected the less time cost. Furthermore, it reveals that the STR time cost estimated by (10) is greater than the simulated results. This is because the tolerance in the estimated cross current threshold by (4) requires additional waiting time.…”

“…(10) shows that the time delay, t de , is inversely proportional to the cross current magnitude threshold I cth . To verify this, comparisons are conducted between the estimated time cost of STR method by (10) and the time cost found by simulation under identical condition. As shown in Fig.…”

“…Operation of a sensitive load can be disturbed by the common voltage sags, swells and interruptions. Recent studies [7][8][9][10][11][12][13][14][15][16][17][18][19] identify solid-state transfer switch (STS) as a possible cost effective solution to power quality problems. STS, see Fig.…”

“…Two common control strategies of STS are the break-before-make (BBM) [9] and the make-before-break (MBB) approaches [10]. The BBM controller transfers the load to the alternative power feeder after the primary feeder current has ceased, whereas the MBB controller initiates the transfer to the alternative line before the current has expired [10].…”

Impact of Difference of Feeder Impedances on the Performance of a Static Transfer Switch

“…This paper investigates performance of an STS system under out-of-phase conditions of the voltages at the STS terminals, due to the difference in the impedances of the utility feeders that supply the STS. The IEEE benchmark system STS-1 [1] is used for the investigation. As in conventional practice, it is assumed that the STS control system is designed based on in-phase STS system voltages, and the impact of the phase difference on the transfer time and the cross current is explored.…”