typically in a delta y configuration. The per unit seen by the primary protection. Others, if we have face protection, face current protection on the primary, it doesn't see something necessarily proportional to the secondary side. So, if I have fault current on the secondary side and I'm expecting the primary protection deal with it, I have to be aware of this non conventional consideration. And again, winding damage on through false is a function of through current on any one winding. So, we must adjust the damage curve to take into account that's difference in per unit current seeing between the primary and the secondary. If you look at the way delta system is connected. There's no ground connection on the primary side. And on the y side, very often, the neutral connection can be consider or is grounded. The point that I'm trying to make is if we measure the current through the transformer on the phase downstream on the secondary, we can measure one per unit current, but it corresponds to the phase on the upstream. But in the case of a primary, I mean, a secondary fault on the secondary side, that one per unit current is shared by two phases on the primary. So, again, Currents for single line to ground faults on the y side, where we have our protection on the primary side. So, no, it's not nonlinear characteristics of the iron. This is strictly phase, winding shift. So, there's a thirty degree shift just automatically in current versus voltage realm, but in the magnitude of the current For a line to ground fault downstream, we need to adjust the fact that on the primary side, we're only looking at fifty eight percent of what that current is. So the point is we need to have a more sensitive protective device if we're using primary protection. And that's taken into account by offsetting that damage curve when seen by a primary device, or primary protection. Now, again, this applies only for ground faults on the secondary and it applies only for primary protection. And again, EC Power does this automatically and that's why I'm kind of hammering on this.