Hello all,
can anybody tell me what the cutoff frequency of the input low pass filter of a voltage / frequency protection relay, such as e.g. SEG MRN3, would be?
The manual says the relay applies an analog filter to get rid of higher harmonics before it applies digital DFT filtering. I am...
Hi guys,
what current is usually measured by the overcurrent protective relays installed at synchronous generators below 10 MVA?
Do they measure the true rms value (that is, all harmonics) or are some harmonics filtered out?
How about the DC offset during a fault or transformer inrush? Is...
thread238-222884
Hello,
I have read in a certain thesis that the residual flux of a transformer which is de-energized but is left connected to a load will decay to zero. We are talking about immediate decay.
I cannot explain to myself how would a passive load be able to do that.
Does anyone...
Hello,
I am performing some simulations with CAT gas engines (3800 kW).
I wonder if there is any time limitation to the idling mode of a gas engine. So, let's say, the gas engine is running and the generator that it is driving is connected to the grid, but is not injecting any power. I.e. the...
Hello,
I am performing some simulations in PowerFactory where I energize a transformer (13 MVA, 57/10,5 kV, YNd11) on the LV side (delta side) from a 7 MVA synchronous generator (with the star point solidly grounded).
The inrush current causes 2nd and 3rd harmonics to appear in the generator's...
Hello,
this is my first time posting in this great forum and I think I might have an interesting question.
I am performing some EMT simulations in order to study the effects of energizing a transformer. I have several transformers running in an islanded network and I get the sympathetic inrush...
