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Thank you for your taking time out of your day to submit a response. I love the exchange of ideas and community on ENG tips. Thanks to all, RProznick

Forgot to include the attachment for my question. RPhttp://files.engineering.com/getfile.aspx?folder=83d40dda-f373-4ee1-b71b-b43b84e6a1a3&file=Wetting_Methods.doc

I have subsation design where three hydro plants are going to tie into the sub of one of hydro plants. Between the generators and the sub, there are a total of 7 breakers and 10 protection relays. I am trying to simplify the wiring requirements from the relay digital inputs and the breaker...

DPC, Point well taken, thanks RP

Following DB's advice, I discussed this with an SEL applications engineer. As long as the homework is done in determining the fault currents and then sizing CT's appropriately to avoid saturation, you can use different core sized CT's in differential protection across the generator as desicribed...

David, Thanks for the reply. Yes, using SEL300G for current differential protection on generator. If CT's are operating in linear region of operation or within the 10% correction limitations for ultimate fault conditions, why is there a need to use the matched cores on the high and low sides...

Hello all, I am involved in design of 12.5MVA high resistance grounded (using NGT)hydro plant. Having a discussion on CT sizing on the stators low side. On the high side, bolted fault current is 8574A, which is mostly supplied by the utillity. CT's on the high side C800 600:5 rating. My...

Hello, I am designing a 10MVA hydro plant. I am using an SEL 387 for current differential. I had designed for shorting test switches between the CT's and the relay but was told that industry standard for the differential relay is not to install shorting test switches but wire the CT through...

I am doing a ground grid study for a small islanded hydro facillity connected to a utillity diesel plant. Using ETAP to model the short circuit ground currents in the hydro plant substation (step and touch potentials). In setting up the model for the utillity diesels, should the sub-transient...

Thanks to all:) RP

I am putting together the DC system for a power plant protection system. For the floating DC system, looking for any pro's or con's for fusing both the DC positive and negative inputs of the protection relays or only needing to fuse one side. Is there any standards with respect to fusing for...

Thanks PRC R.Proznick

Have a 13.8KV line, 8km long, coming from Hi-Z grounded generator and it terminates into the delta side of a 13.8kv/138kv delta-Ygrounded transformer, 138kV feeding utility. Normally 13.8kV line is Hi Z grounded at generator but should the generator trip, the line will will go to an ungrounded...

Slavag, The SL attached as pdf cheers, rp

Thanks for the response David, Not shown on the single line is the resistor on secondary of generator grounding transformers providing high resistance grounding for the generators. Installing extra 13.8kv/13.8kv transformers at G1 and G2 won't fly with clients so will work with two power...

Looking for design philosophy with repect to transmission line grounding. We have two distributed generators feeding 7km and 8km of interconnection transmission line to the substation of a third generator site where they will tied and bumped up to 138kv. The output of this 12MVA 13.8kv/138kv...