That equation looks correct for a ph-grnd fault.
As mentioned by others, Z1, Z2 and Z0 are the sequence impedances for the complete conductor group (i.e. phase conductors and any neutral conductor present).
Zn is the impedance of the fault itself (i.e. 0 for a bolted fault). It has nothing to...
Try a Google Image Search for "Transformer Nameplate".
It will bring up dozens of examples of real Nameplates so you can see typical details for yourself.
Also consider Kansas State University. I took a complete Master's degree through them with a full set of power systems courses.
Very happy with the quality. These were live classes.
Regarding the maximum fault infeed of 2x FLA. I do not believe there are any standards that address this. IEEE 1547 doesn't mention anything like this because it covers all DG technologies, not just inverters.
I have seen the maximum short circuit current listed on different manufacturers...
The problem with inverters is that they don't act like a rotational machine. I've also seen numbers of about 1.5 - 2 FLA for maximum fault infeed, but it appears that this is very transitory and only lasts a cycle or so. Like David, I suspect this is due to capacitors in the inverter circuit and...
Solar is pretty safe and quiet. There shouldn't be any problems caused by it due to the solar panels.
Yes, solar is much more expensive than most other forms of generation, but with enough government money, it's often worthwhile for a developer.
The developer is going to have to consider...
Others may be able to provide better info, but I suspect that you will have to use a more complicated model.
If you are interested in solving a harmonic problem, you will need to know the impedances of the loads at each frequency (may not be constant if you have VFDs). A single lumped load...
Is the OP talking about a high-impedance fault or a high-impedance grounded system? cuky has defined a high-impedance grounded system.
A high-impedance fault is just a fault where the fault impedance (as opposed to the system impedance) is high. For example the equation for a ground fault is...
Are you sure you mean 'zero sequence mutual impedance'?
By definition, sequence impedances do not have mutuals (unless you're talking about ugly cases where there are different impedance paths for different phases).
If you are referring to 'phase-ground mutual impedances', then for underground...
Just a thought, but have you calculated what the voltage drop will be through the 100 ohm series resistor due to the 150MVA transformer no-load losses. Might be an issue.
Oops. You're right. Guess I should think before I post. I was thinking about the cost of reduced losses.
The crudely calculated cost benefit of shifting load should be something like A + B where:
A = Reduced generation cost due to reduced need for investment in peaking generation, lower cost...
$685/yr/kw = $0.078 / kwh
That's above wholesale price, but less than retail for residential customers.
Could be reasonable, depending on who's counting.
You can have resonance when the ratio of the capacitance of the bank to the system impedance matches the square of a given harmonic
see: http://ecmweb.com/powerquality/electric_power_factor_correction_3/
This can happen even when there are no major sources of harmonic load on the system.
If...
Most power systems analysis books have a section on Y Matrix solution methods which describe 'node elimination'.
Try a classic like "Elements of Power System Analysis" by W.D. Stevenson for example.
It depends on the type of analysis you are performing.
If you are interested in fault analysis, you can do a lot of simplification of a network simply by combining impedances (just using simple series or parallel reduction).
If you are interested in power flow then network reduction involves...
Oh - and any automatic formatting/capitalizing, etc can be turned off in Word.
When I use Word I generally add my electrical terms to the dictionary whenever I run across them (there are usually < 50 electrical specific terms I use frequently) and often turn off auto-capitals, etc.
danw2 - "automatic index feature, software that recognizes the outline headings and adjusts the page numbers of the index as the document changes"
MS Word already has this functionality and there's a ton of books, training and websites available which will tell you how to use it.
I'm afraid...
If you've already got the data from the collectors/devices into a PC running a SQL server, you would just use regular IT techniques to get it to the control center. No need for specialized protocols.
I.e. you would either replicate the database to a machine in the control centre or you would...
Here's my understanding...
Long term planning includes the following sorts of studies and are normally performed under nominal configurations (either for expected average conditions or peak conditions depending on the study purpose):
- baseline load flow and short circut studies
- optimization...
Ontario utilities regularly supply residential customers from the 27kV system, and I think also occasionally from 44kV. So, I don't think there's any intrinsic problem with the transformer ratio.
Protection shouldn't be a huge problem either. As you mentioned, there is little infeed from the...
