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Hi everyone, we are designing a water treatment plant. There are several pumps and compressors. The client wants to use Siemens simocode Pro V relays, but I don't know the range avaible to set the unbalanced load relay (% of unbalance or delay), niether the setting I should use. I surf all over...

And if the transformer-line-transformer allows a reasonable voltage regulation...

busted! I googled for "Zig-Zag transformers" only :p thanks a lot!

Hi everyone, I'm sorry if this question is already answered, but I didn't find it. I have a 132kV system, a 132/13.8kV YNd transformer and a Znzn transformer to provide neutral on 13.2kV system. I need to calculate LG short circuit current, so I'm using ETAP. I don't know how to simulate the...

Thanks everybody for the advices. This what I did after all: I deactivate the instantaneous protection and set the Long time overcurrent protection 1.15 FLA (IEEE Buff book). Time delay was coordinated to trip the CB with the 51V (voltage restrain)as backup of the feeders protection.

Please educate me: The system is something like this: network---xfmr---bus---generator | other loads If there is a 3ph short circuit in the bus, should I need to cordinate de generator device 50? Isn't the best thing to trip the generator as soon as possible...

It's a 2MW cogeneration system added to an existing plant. I don't have info about the rest of the plant protections yet.I'm trying to save some time starting with the generator protection earlier. I thought I could use the 50 to cut the deliver of current to the bus it's connected in case of a...

Wich is the usual setting in % of FLA of an instantaneous relay (50), protecting a generator against external faults?

Hi, I'm modeling an existent oil refinery electric system in ETAP 6.0.0. I don't have the cables used there in my lybrary, and I can't find the minimum data it requires to create it (zero sequence impedances, in example). Does anybody has it? do you know where can I find theese data? Cables are...

The frame is the max. continous current that the CB can be seted to open (not under fault conditions, but overloading for example) in the long-time characteristic curve. The trip is the actual current that the CB is seted.

You don't calculate it. It must be provided from the manufacturer and It's obteined with the Test described by waross. 5% is a typical value for that transformer.

The first number is the phase conductor size (3 of the 4 cores)and the second one is the neutral conductor size (both in mm^2)

Take a look to this document. It's in spanish, but the figure in the Error#1 it's very clear. It's the recomended array of cables of the same phase running together.http://files.engineering.com/getfile.aspx?folder=f927d4c4-1af0-4e41-a974-e2fc04dbdb38&file=Errores_en_el_trabajo_con_cables.pdf

Tha calcs are Ok, but not the values. 3. Uk(H/X)=12% to 6.8MVA base 4. Uk(H/Y)=5% to 0.8MVA base 5. Uk(X/Y)=7.5% to 0.8MVA base I thought the "to" was the base of the impedance after the pwrtran post. I think that my first post is the right one

let me know if I'm wrong: Z=Zpu1*Zb1=Zpu2*Zb2 Z=U^2/S Zpu2=Zpu1*(Ub1^2/Sb1)/(Ub2^2/Sb2) If the impedance in pu it's higher or lower depends of U^2/S ratio Anyway, I think those values are odd, so maybe the Uk given are not in the base you are saying

Using 7.6MVA as base: z12(7.6) 0.05pu 5% Z13(7.6) 0.0003pu 0.03% z23(7.6) 0.0004pu 0.04%

The rated power is the winding power, so the minor rated power in the power flow is the one you are looking for (0.8MVA). Z12=12% z23=7.5% Z13=5%

Argentinian codes (IRAM) are based on IEC codes, and it's acepted the European 400V standard for equipment nominal voltage.

I just read this: Primary: 6.9/13.8kV Delta Secondary: 600Y/347 sorry

there are 6 conductors per phase