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Thank you to all who replied. Turns out the reason the vendor was mentioning voltage drop up to half of nominal DC voltage was due to the fact that in Europe for some projects they use a different Trip coil monitor where one relay input is wired as shown in my figure above, and then an...

For Trip Coil monitor and Close coil monitor we use a Protection relay Input (high Impedance) wired in parallel to the Tripping relay output contacts, and in series with the Trip/close coil and the 52a/b status. Has anyone ever had issues where the relay input (125VDC control voltage) would not...

If I can't find the CT Thermal Rating Factor TRF (or Rating Factor RF) on the nameplate, is there a way to find that knowing the CT class? In other words, how can I come up with a TRF if I do have the CT nameplate data and saturation curves. Station that I am doing settings for has this 1960s...

The settings sheet doesn't specify, but let's say it is.

What does 'F' mean. I have a settings sheet for a DPU ABB relay. The 50P setting is shown to be 'F'. Does that mean it's OFF.

@Steven , Now if I do have a delta tertiary on the Auto txfmr, and also on the Yg-Yg txfmr, would I then need the zero seq. filtering? Would I need the filtering on both HS and LS windings? Also does it matter that there is load connected to the Delta tertiary, or if it's there but not being...

The zero sequence network for an Auto TX and for a Yg/Yg transformer both show that there is no connection to the ground bus (No), which means there will be no 0seq current flowing through that circuit (unless there is a Delta tertiary which does connect to the ground bus in the 0seq network)...

My transmission line's Zero seq. impedance angle (89 deg)is higher than its positive seq. impedance angle (79 deg). Is this OK?

Can someone please explain what Breaker column failure is, and how does this protection work.

I am setting a GE D60 relay and trying to get some clarification on what the intent is for this OFFSET setting and how to set it. I usually use SEL relays. The GE manual doesn't go in detail about this setting. I do not have series compensated lines. Any help would be appreciated. Attached below...

Exactly. The only device I can trip is the recloser. So I can only isolate for conditions caused by through faults. But is this reason, that there is nothing on high side to trip, enough to say that I don't need to have 63/71 trips?

I have a customer that has recently installed a 4.75 MVA distribution transformer (23/4.2kV)that comes on a skid that also has a recloser, regulators, and isolation/bypass switches. I have fuses protecting the transformer on the high-side. The only trips on the transformer were for 63FPX (Sudden...

odlanor - there are no CTs on this unit as of yet. If we go with this TCG scheme, then I would have to tell the customer to buy the TCG CT that connects the tank to earth (as rcwilson mentioned). Another thing I didn't mention is that this transformer is on a skid. The skid has this...

I have to implement a Transformer Case Ground protection on a 5MVA Delta (23)/Wye (grounded)(4.2) transformer. The transformer has no high side breaker, only Fuses; Low side has a recloser. I have never used this scheme before.I have included an IEEE excerpt about the TCG protection below. What...

A customer provided me transmission line impedance for a 69KV line in matrix format. He got it from ETAP. I am used to of getting impedances in R1+jX1 and Ro+jXo format which is exactly what I input into ASPEN. Can someone please help me with reading or decyphering these matrices to obtain my...

shams, I haven't started at all so have no idea what I will be using. There is another person taking the test from my office and she has some books but I don't know yet the names. Sorry.

I am planning to take the PE exam this fall in NC, and I was wondering if anyone from NC knows where the PE preparation classes are held. I am in Charlotte, NC. Thanks

Thanks for the input guys. David, I don't think there is any other rating on this Transformer that I know of. Again, this is just the planning phase and we haven't ordered anything yet. Also, this TXfmr is feeding only one feeder which has a recloser on it, so I think overload protection will...

I have no experience with fuses (other than some fuses on radial distribution lines); I need some help coming up with the fuse size to protect a 3.75/4.68 MVA distribution Transformer. The fuses obviously are on high side (Delta 23kV) and the low side is Wye-grounded 4.16kV. I have looked into...

I have an old relay settings file that is referrring to the 'Winter DAL'rating (given as 32MVA) and has the Inverse Time-overcurrent element pickup set above it. Can someone explain this a little bit. I searched online and I saw apost saying that you shouldnt load the line for more than 5 mins...