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Thank you for all the responses so far. Very helpful. Do you all know which standards apply here? IEEE, ICES, CSA, ANSI, IEC. Sincerely, Zeeshan

Looking for some suggestions on possible causes of radio interference on a 230kV line, which would be in the frequency range of 70 to 250 MHz.

Bill, We don't have spare CT available, nor do we plan on changing any phase to ground connections to phase to phase. Do you know why I am getting A and B phases to be 180 out?

Bill, Here's the connection I was thinking of, but unfortunately during the actual test it appears that A and B phase are 180 out. Can anyone explain with the math why? http://files.engineering.com/getfile.aspx?folder=1a922980-c852-457f-927e-a7af827eebc5&file=CT_connection.jpg

This is a metering Unit. No relay protection is intended. Any modifications would be a temporary fix until the unit is repaired.

Also, just to clarify by combined unit, I mean it's the instrument transformer where both the CT and PT are combined in one housing.

Hello All, One of our high voltage combined instrument transformers has failed and has to be replaced. I am trying to figure out a way where the secondaries of the remaining two CIT's could be used to create voltage and current for the missing unit for a balanced 3 phase power system. Will...

All, I have been asked to look into the probability of Main Power Transformer (230/35kV) failure should one be implemented without high side arresters. The thought process behind this is to figure out the affect of energizing a transformer without an arrester due to lead times of the...

What type of cables does this section applies to? Does it apply to instrumentation cables, which are covered under 727? What's the purpose of this limitation? Any suggestions will be greatly appreciated.

jraef, thanks for your response. My question is in regards to a high voltage air-disconnect, where the quenching medium is air. My concern is that the arc from the blade on the switch jumps over to the conductor (connected to the jaw side of the switch) during closing and stays on until the...

Does anyone know of any chart, code or standard that describes minimum metal to metal spearation for different high voltages during switching to avoid and arc? I have read some references where it talks about accounting for 1 ft per 110kV, but am not sure where that number came from.

This is an interface with a Utility, which only provides KYZ output from their meters. I just need to get a pulse counter that can support serial modbus or DNP to SEL 3530.

I am trying to figure out a way to get KYZ pulses from a revenue meter into a SEL3530. I am therefore looking for a middleman relay that would take KYZ output from the revenue meter and then convert that info. to a serial modbus or DNP communication to take over to a SEL3530. Any suggestions...

ek, please review NEC 310.

Cranky, I understand that a drain coil in series with capacitors functions as a high pass filter for carrier frequencies, but I also understand that it's an optional accessory, which comes only if a CVT is ordered with carrier accessories, thus making it suitable for PLC communications. It's not...

Does anyone know if there's any US standard or code that dictates what the oneline symbol for Capacitive Voltage Transformer (CVT) should be? I have always seen one with a drain coil in it and know that drain coil should be for CCVT and not CVT.

Thanks jghrist for calling out my laziness :) I was just trying to save time by not having to look for it if someone already knew where it was. I was able to get it from IEEE Explore site.

Do any one of you has a copy of Ralph Lee's paper on application of rolling sphere lightning protection method they wouldn't mind to share? Please don't bother with a generic reply such as go find it in IEEE archives etc. unless you know specifically where. Thanks again.

Good morning All, I have an application requiring three of my air conditioner loads to start in step in order to avoid having to buy a bigger size emergency generator. my three airconditioner loads are as follows: -240V 60A single Phase AC -240V 60A single Phase AC -240V 30A single Phase AC...

Bill, That was my understanding that the mid tapped winding will carry 2/3 of the single phase load (2/3*120 =80kVA) and 1/3rd of the three phase (1/3*51 = 17kVA). The other two windinging will take 1/3rd of both single (1/3*120 = 40kVA) and three phase loading (17kVA). However, now I am a...