I have an installation where CTs and PTs are installed, but will not be used (not wired for metering nor protection). We will be connecting all phase CT terminals to ground to avoid an open CT situation, but the field contractor wants to also ground phase PT terminals. Is that typical? Those...
I'm installing 18KV underground cable from a new tap-box, to an existing one (see oneline attached). The iso-phases and tap-boxes are isolated (frames are not bonded) in all locations. Each Tap-box has a Power Transformer for metering. Through this set-up, both GSUs will be feeding separate AUX...
I'm feeding a 480v MCC system by (2) MV 4.16KV feeds, through (2) 500KVA Transformers. We're adding a 550KW emergency generator to one of the MCCs. The question came up, whether we should add low impedance resistors to EGEN and XFMRs to limit grounding current. I've seen multiple applications...
I was told by VFD vendors that we need to double the size of generator supplied VFD loads. I also read many articles online saying the same thing, like the one at ABB site: https://library.e.abb.com/public/0007878791e17d0985257cca005bb048/LVD-EOTN64U-EN_REVA.pdf
On the other hand, my generator...
Our specification indicates motors 20HP and above should be equipped with a space heater. I believe this has to do with a balance between price Vs condensation issues. My question is, how to determine when a motor space heater is required? I know we're trying to keep non-running motor...
I have a 350A neutral resistor for a 2MW generator, and I'm trying to determine size of neutral resistor cable. I used equation: (1/A)^2 *t = 0.0297*log[(T2-234)/(T1-234)], and came up with A=23,643 (t=10s, T2=150, T1=90). This means I can use #2 AWG cable. The phase conducts are 6-1/C #250 (2...
I have a situation where a client has a 480v, GE WPH Tie circuit breaker that needs to be manually closed. I didn't see sync checking in it's closing circuit, so I know there is no automatic voltage and Phase angle check, but the 500KV feeding network should be the same, and both units should...
Hi there. Does anyone has a typical standby generator Schematics showing interlocks, triping contacts, and indications? This is for a MV standby generator feeding a switchgear line-up through a feeder breaker. The switchgear has a main breaker, and is connected to another lineup through a tie...
We are planning to install a 2MW, 4.16KV stand-by generator to feed existing MV switchgear. Are there any special requirements for the Generator Breaker? IEEE C37.013 talks about DC components of fault current up to 75% (due to high X/R ratio), but the standard indicates it applies to "all ac...
Client had asked if we could add a temporary 4160v generator to feed their 4160v lineup. This would be connected directly to the MV bus (there is no available CB for this connection). I have the following questions:
• What would be an advantage of using 480v generator Vs 4160v?
• What generator...
I used ETAP software to design 44KV substation ground grid. For the shape of my particular substation, I had to use Finite Element Method, and not the IEEE 80. My question is regarding Meth sizes, and conductor spacing. The IEEE 80 design requires that minimum spacing between conductors is 2.5m...
