When designing the overhead transmission or subtransmission lines, how does the Seismic area play a role? Does the NESC indicate this problem? Assuming I'll design to meet the Grade B standards.
Thanks
James001
Have you guys have any experience in burying the 15kV cables under the long lake. Since the lake is too wide, the client decides to cross the lake via underground. I think I can lay the cables on the bottom of the lake or do I need to bury the cables 3-4' deep below. What are the restriction...
I'm working on the 5kV standby generation at the water treatment plant. I spec'd out that each 2000kW gen must have 500MCM cable connected to the 4160V bus. My question is, does the cable needs 1/3 concnetric neutral, if not, how are we going to ground this, or does it need the ground at all...
I have the Beckwith M3425 relay protection on the 72MVA generator. This gen can run as normal (producing power to the system) or it can run without the turbine (produce only VARS to the system for voltage support, synchronous condenser mode). When doing the settings on the relay, I can program...
My way of doing the settings are as follows:
**Set the phase pickup at max load or 110%
**Set the ground pickup at 50% of the phase pickup (make sure the ground pickup is greater than the largest tap fuse)
**Instantaneous setting depends on your application. If you have a downstream fuses, would...
make sure you use the microprocessor relay such as SEL587 because it can accept any CT connections as well as any range of CT ratio. If you're planning to use the old mech relays such as HU type etc.. then you need to connect the CT as Ralph indicated and be sure that the CT ratio mismatch etc...
I have ungrounded system and want to install the 59N relay to detect the ground fault. When I did my calc, I concluded that I need 6.7 Ohm, 6500W resistor and connect it on the secondary side of the open delta PT, 120Vac
Do you know where I can get this type of resistor? I tried Post Glover...
It happened to me on a project in SD. We set the relay and everything seems working fine until the customer increased the load, once they switched their line and increased the load, the 87T operated. We checked and checked and concluded that the phase input into the relay were wrong...
Thanks for the answer.
The reason I ask that is because everything is set and done and there is an ungrounded section (13.8kV switchgear) between the GSU transformer (delta connected) and the generator breaker, which does not have SLG detection. The switchgear also has couple aux transformer...
I have a delta wye transformer with generators connected on the wye side. I'm wondering if there is a single line to ground fault on the delta side (assuming there is no other source on the delta side), how do I calculate the fault contribution from the wye side. I know there is no current...
Does anyone know where I can get info on the T-line impedance. I have 795ACSR line with normal tangent structure and wondering how to obtain/calculate the impedance per mile (ohms/mile)
thanks
james001
Here is how I would calculate the MVA SC. Assume you are given 10000A of short current on the primary side of the 10MVA, 7.5%, delta-wye, 115kv-12.47kV transformer and you would like to calculate the short current (in terms of MVA) on the secondary side of the transformer
You need to convert...
Thank you MikeDB for your input. Also is the rule of thumb when you try to sag the conductors, you want the sag to be about 1%-1.5% of the avg span at 60F with no wind. It means that I can stretch my 795ACSR to 5000# max under NESC heavy load with Grade B construction. When I run my short...
