As LittleInch pointed out, consider the refueling logistics when determining the appropriate size for the new tank. If your requirement is for 24 hours of actual run time, it may be helpful to size the the tank to allow for at least 6 months of routine testing loads in addition to the fuel to...
The typical inrush curves for transformers assume an infinite bus approximation. For an islanded system with a transformer larger than the generator, that will be a rather poor assumption.
I am rather confused that the links suggest that 0.5% probability means something will never occur. If...
Oil containment rules vary by state. The requirements in my region are that oil cannot escape into the watershed. For temporary installations far from water, the oil spill prevention plan would typically be to remediate any oil spillage by removing all contaminated soil. There is cost analysis...
The 230 kV/66 kV ratio is a bit higher than typical for autotransformers. That being said, it seems weird to have the 66 kV system ungrounded.
Many regions are eliminating tertiary windings on 400/230 kV autotransformers.
The GE publication The-whys-of-wyes provides good info on why to choose each configuration.
Your application also matters. Do you have a load, a generation site, or a mix of load and generation? Increased distributed generation is make wye-delta-wye transformers more attractive.
It would be atypical to have ungrounded wye PTs. It is common to have ungrounded PTs in an open delta configuration.
In certain cases grounded wye PTs are used on capacitively (i.e. ungrounded) systems. In this case the PTs must be rated for full LL voltage even though they are connected LL...
My utility specifies an allowable range for each size of transformer size when buying transformers. This allows us to then publish a table of max kAIC for customers to use in their designs. Here is an example:
When designing an installation, it is import for a customer to design for the worst...
No. The typically tests are done on will the transformer filled with oil. Oil is an integral part of the insulation system you are attempting to test.
The one exception I can think of is a sweep frequency analysis (SFRA) test to detect any damage that may have occurred when shipping the...
Substation yard rock has lots of gaps/texture, so it any measurement from the surface of the substation rock would be limited to no better than 0.5 inches. That is find for generals measurement like a 14' truck plus 4' of additional clearance. However, that would be insufficient for...
Prefault current of 17 amps might be a branch/tree sitting on the line for a short duration before the fault evolves to low impedance.
Can you post the waveform recording? When the fault magnitude varies throughout the fault it is unclear to me which instant the relay uses to calculate the...
I have seen shield wires on incoming lines are intentionally isolated from the substation ground grid with a 15 kV class insulator. I too am curious about all your questions.
As I experimented with various configurations, it seemed like X0 and R0 sometimes go in opposite directions for a change in circuit configuration. I don't recall seeing anything change by a factor of 6.5 though.
Perhaps there could be current flows on the distribution circuit cased by the...
I am not sure what you mean by RYB indicator, but please consider what will happen if there is a short circuit between PT and the RYB indicator or fault inside the RYB indicator. I do not recall ever seeing the secondary of a PT directly connected to an instrument with a fuse or breaker as the...
