General Discussion

Power transformer modeling

Submitted by alain.xemard on Mon, 10/21/2013 - 15:15

The CIGRE working group A2/C4.39 is finalizing an important report on the electromagnetic behaviour of power transformer. This long document (more than 300 pages) is titled : "Electrical transient interaction between transformers and the power system". It includes a lot of information on how transformers can be represented when modeling electromagnetic transients, but you can find also measurements on real transformers.

This document has been distributed for review in the study committee C4.

Script for changing variable with time

Submitted by dij.joshi on Mon, 07/01/2013 - 18:46

Hello everyone,

                      I am doing a load flow study on a feeder. One of the bus in the feeder is PQ control type. Instead of doing load flow once,I need to do it multiple times changing P and Q with time to study loss on the feeder. I am wondering if anybody has an idea how to do that or similar script that can do that ?

Thanks in Advance

Dij

DJoshi

MSEE

Northern Plains Power Technologies

modeling Power Swing

Submitted by idrees.omer-aziz on Thu, 06/27/2013 - 14:50

Hi everyone, 

I'm a fairly new user with very little EMTP usage experience. 

I would like to know if anyone has modeled Power Swing in EMTP for the purpose of testing the Power Swing blocking function in a relay. I am trying to do the following:

-  generate a power swing condition (1st stable and then OOS) and observe relay behavior. 
-  generate a fault during the power swing and observe the relays ability to differentiate between the power swing and trip only after it recognizes the fault.

I hope I have articulated myself apprpriately. 

Shunt reactor modeling with non-linear inductance

Submitted by Andrew.Robertson on Mon, 11/19/2012 - 19:04

I am wanting to model a 50 MVAr 132 kV shunt reactor (1.11 H), which is being supplied as part of a 132 kV cable project.

As I am looking at ferroresonance issues, I'd like to model the reactor as a non-linear reactor.

How do I translate the reactor design parameters to a current versus flux relationship ?

The reactor must be linear to 130% pu of rated voltage (= 171.6 kV ph-ph). Maximum flux density in iron at power frequency, principal tapping and 130% rated voltage is 2.1 T. This is the only information available as it is still under construction.

Negative Voltage MPLOT

Submitted by adam.king on Fri, 11/16/2012 - 00:11

Hi there,

I'm fairly new to the software and have been doing some analysis on EMPT using a frequency dependent model. I was wondering if someone could explain or refer me to a paper/journal/book, as to why I see negative voltage plots using this method and only positive voltages when using a constant parameter model. Does it have to do with the initial conditions on each phase (ie 1.1pu of say 118, -59, -59) and a negative polarity surge (ie connecting -ve end of current source to the system)

Cheers

X