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Hi! I have one question. We have ungrounded 10 kV network. Transfromer 10/0.4 kV YYn0 connected to this network. 0.4 kV side of TR is solid grounded. Question: If I perform loop test at 0.4 kV side, I will see real earth fault current? For example I check it by Megger LTW425.

Hi! When we perform SC calculation, should taking into account motor contribution current from LV motors (0.4 kV or less) or only from MV motors? In which standard I can find information about this? Thanks in advance.

Hi! In your opinion, which software is better ETAP or DIgSILENT PowerFactory?

Gents, I have some problems with understanding information from datasheet of induction motor. I hope you will help me. I have induction motor 10MW. I found followed information in datasheet: Safe stall time: a) @ 100% V 9 sec (hot), 14 sec (cold) b) @ 77 V 15.2 sec (hot), 23.6 sec (cold) c)...

Hi! Please, give me titles of "must-read" books about power electronics. Especially, I'm interested to find books about VSD like LCI or VSI. Thanks in advance!

Hello! I need your help to clarify some aspects of VSD working. I made the model of VSD which fed a motor (model.png in attachments). The VSD connects to the grid via transformer 35/5 kV Yg/D. I can't understand, why phase voltages change on the motor side when the earth fault occurs on the...

Hello, I would like to discuss carrier pilot protection. Do you apply this type of protection for high voltage lines in your country? For which voltage level? Which is the principle of operation using? How is pilot channels organized? And the last question. Do you think, this protection is...

Hi gents! We have islanded power station with some GTG 10.5 kV, each GTG works with step-up transformer 10\110 kV. There is a resistor installed in neutral each GTG, which limits earth fault current to 10A. My question is for which purpose need this resistor? Why we can't work with an...

Hi everyone! I'm starting to study wind generation and relay protection at wind farms, so I want to ask you to help me with books about this topic. Which must-have books about wind farms exist now? Can you share some of them? Thanks!

Hi! Need yours help with ETAP and check synchronization. I'm trying to make condition when two independent systems unite by closing intertie CB. So I need to set some angel between two systems and then check synchronization with some parameters. How I can to setup angle between voltage in ETAP...

Hi gents! I have some problems with IED GE F650. Can you explain how to get logic equation (PLC) from relay? When I open to PCL editior, I see that button "Get project from relay" doesn't active.

Gents, I have some problems with choose of time delay for 50N sensitive (core balance CT). I have 10 kV network, where neutral grounded through resistor (150A). Which minimal time delay 50Ns recommended for this type of network? I chose time delay 0.05 sec for feeder which supply transformer...

Hi. Are there existing free tutorials for ETAP on the internet? Can you share links please?

Hi! I'm trying to study transient stability our islanded power plant and I came across at some problems. Firstly, I couldn't find any technical papers about transient stability of islanded microgrids. Can you recommend me something? Secondly, I have islanded power station, which consists from 8...

Hi. I hope you can help me to understand this situation. We have SLD double sectined busbar 110 kV. There is simple SLD below. There is island station 110 kV. When our object was in project stage, project engineers decided to leave one of Bus Couplers at open position and wrote this information...

Hello! Can you help me please, I'm trying to find information about inertia constant for turbine Siemens SGT-800, but can't. Maybe someone knows this value or WR^2. Thanks!

Hi! I have a basic circuit diagram of a 3 phase synchronous generator and I can't find descriptions to these parametrs. Can you give me books where this will be dicribe or explane what are mean these parametrs? Thanks!

Hello. I'm trying to use the transient stability test by ETAP and I have the problem. When I tryed to run transient stability test, I got error '10-04-2019@08:41:03 TS calculation aborted due to negative syn. machine saturation factor(s) at t = 0.000 sec.' Can you help me please, why is it happen?

Hello! I'm looking for RS232 to RJ45 cable pinout diagram for IED GE MM300. Where can I find it? Thanks!

Hi. I need help with GE C60. There is a power line 500 kV which proteted by GE. This power line connect two independant electrical systems. How can I do a function of close breaker with catching of synchronism when this line, for example, open by protection? As I understand C60 has only control...