Thank you for the valuable feedback.
I think my thought process or goal with the PMP was to get a more formal exposure on project management (outside of the actual hands on experience in my career) in order to be a more effective leader in my current engineering manager role with supporting...
I have recently been kicking around the idea of obtaining a PMP certification.
I am an EE and registered PE with approx. 15 years experience in Power Systems Engineering which has been a good mix of both design/consulting as well as project management for various projects. I have recently...
After I posted this it just so happens that I was looking for a narrow frame MV vacuum breaker to replace and existing air break device and noticed that a particular manufacturer only offered this narrow frame breaker with an MVA (K>1) Total current rating.
Again this leaves me wondering why...
In a follow-up to the last sentence in my previous post I want to compare the fused switch combination rating with that of a fused contactor combination rating. In the above example it seems that the fuse switch tested combination only allows the switch structure to be rated slightly higher...
LionelHutz
That makes sense what you said about using the lower of the two.
I guess for the momentary rating of 64 they took a similar approach using the lower of the two (61kA) but somehow through testing/calculating they are able to use 64kA for the momentary rating.
So when comparing to...
7another 4
Thanks for the response. Looking at what you posted and looking more into this it seems that manufacturer provides a "series rated" or "combination" listing for the entire structure (in this case just the switch and switch structure) based on combination testing with the fuse and...
Does anyone know of any good online college university courses that would be beneficial for gaining a better foundation for synchronous machine theory specifically related to synchronous generators. I've been doing of system protection recently involving generators and would like to gain a...
To me it appears that the DCT's are the CT's providing differential protection with flux summation or core balance CT's. Because the CT is around both the generators neutral and terminal leads that tells me that the actual CT will have a CT on each phase of the stator winding with both the...
I'm having trouble seeing how the generator differential scheme on the attached One-Line will work. It uses flux summation CT's around the generator neutral and terminal leads inside the generator enclosure with the flux summation CT's connected to a relay with another set of CT's on the bus...
Yes re-closer CT's are 1000:1 CT's.
As I complete fault analysis I notice that there are potential issues with re-closer fault ratings and CT saturation due to their close proximity to a generation station. 23MVA generation station at 13.8kV is located approximately 500ft from this existing...
Thanks for the responses.
Zeroseq - Is there rule of thumb for de-rating the motor thermal curve to account for reduced operating speeds? That is a very good point. When you mention coordinating the relays inverse time curve with the fuses do you mean having the relay time curve below the...
Marmite
Thanks. I'm curious in your mind what makes it a "cheap and nasty implementation"? I tend to agree with you but was curious what items jumped out in your mind as leading to that conclusion. Does it have to do with the fact that overhead cable is used instead of bus? Or does it have...
Cranky108
I'd be curious to hear more on situations where "it depends". Would it just be cases where minimum fault current needed to be considered for protection and coordination?
Currently reviewing the protection and control in a new 13.8kV outdoor switchyard and was curious to hear if others would recommended implementing differential protection as part of the switchyard protection scheme.
This new switchyard is fed from an existing Utility substation (12MVA...
I am performing some short-circuit calculations on a 13.8kV distribution substation which has 267kVA Step-Type Voltage regulators on the feeder circuits leaving the substation. I was wondering weather or not the impedance of these regulators needs to be considered for any aspect of the...
I am reviewing an application where a 4.16kV MV VFD is being fed from an upstream MV MCC through a fused contactor. The contactor has a multilin 735 relay on the feeder to the VFD. It also appears that a multilin 469 relay will be located at the VFD enclosure for providing motor protection in...
