For delta-wye 161-13 kV transformer, I'm not seeing a 30 degree shift between primary and secondary currents. In fact the secondary currents are LEADING the primary by 120 degrees. This is being seen on a SEL 787 relay. At this point the transformer is lightly loaded. Is this correct?
Should I use the single line to ground or double line to ground fault value in substation ground grid design? The DLG fault is somewhat higher but IEEE 80 is confusing to me.
I'm working on the specification for a 161/69/13.2 kV, 36/48/60 MVA, autotransformer with a loaded delta tertiary and a zig-zag grounding transformer downstream of the tertiary. The HV and LV windings are wye connected and solidly grounded. I'm specifying the tertiary winding with a 110 kV BIL...
I have a question about metering PT's at an industrial substation, 115-13 KV, with two 12 MVA, delta-wye transformers that are grounded through 35 ohm resistors.
The power supplier says their normal practice grounding the metering PT's through the grounding resistor.
These makes me very...
