In part Ⅰ, we explain how to coordinate transformer primary-side fuses with a secondary-side automatic circuit recloser, such as in a utility substation. We'll use the "conservative" coordination method, which ignores the effects of fuse cooling during the reclosing time intervals (contacts open...
1. Note that one set of three-phase CTs and associated relays constitutes a single CT secondary circuit. Fig. 1. CT secondary circuits for radial feeder scheme. Regardless of the number of secondary windings in a circuit, the secondary circuit should be solidly grounded to the grounding grid ...
One solution is to use, instead of a spider box, a 240V-to-120V step-down Transformer/Distro, like the ones we sell for the Honda portable generators that have variable taps that allow you to boost the voltage on the secondary side. Our standard Transformer/Distro is designed to boost the...
whichever is less (IEEE P1610/D03, 2002). This trip thresh-old should be at least two to three times the load on the circuit to minimize false indications. These two conditions will almost never conflict, only at the end of a very long feeder (low fault currents) on ...