Hello everyone,
In a MV distribution network with local gas engine generators we use directional relays due to the meshed topology of the grid.
Step up 34,5/ 0,48 kV transformers associated to generators are protected by reclosers on the HV side. These reclosers have two groups of settings...
Hello Dear Colleagues,
I have a 4,16 kV industrial switchgear with high impedance grounding through a ZigZag transformer limiting fault current to 50 A.
Unfortunately the MV metalclad switchgear came without zero sequence CTs and some phase CTs have a high ratio 2000/5 limiting both...
Dear Sirs,
Could you please explain the meaning of a feature called "DEF plain and Blocking modes" in distance relays?
Thanks in advance for your help.
Regards,
Charlie
Dear Sirs,
I am dealing with the replacement of a generator protection system which includes an electomechanical relay type CUH90C from Brown Boveri for detecting stator grounds. The fact is that two voltage signals are wired to the relay namely one from the grounding transformer and one from...
Hello everybody,
Where could I find guidelines for protecting wound rotor induction motors?
To the best of my knowledge, protection of this type of equipment is achieved in the same manner as for squirrel cage induction motors. But there are still some concerns regarding rotor winding faults...
I got a comtrade file with two current signals. Is there any way to create a new signal from the difference of these former ones? If so, Could this task be done in excell?
Thanks in advance for your help
Hello everybody, i'm an electrical engineer and actually i'm performing dynamic simulations of wind turbines but i have had some difficulties with data avaliability. Particularly those data related to equivalent wind speed time series and equivalent torque coefficient tables. (equivalent...
I have two questions about the same topic:
Can anyone explain with some detail the phenomenon of end region heating limit in synchronous generators?
How can i obtain the equation for the curve associated with this limit in the synchronous machine capability curve?
Hello everybody.
Current transformers normally are specified for a maximum transformation ratio error under certain conditions.
1. Does this ratio error always tend to give a lower value of secondary current than expected? (due to excitation current)
For example if i have a C800 10P20 6000/5...
Is there something like a standard specifying maximun voltage differences before closing breakers when attempting to interconnect two systems?
As far as i'm concerned this depends on voltage level (230 kV is not the same as 4,16 kV). I would like to know if current operating practices applied...
Hello everybody, i'm trying to estimate voltage at terminals of several motors based on estimations of voltage drop from motor control center. what assumptions can be made about conductor parameters? (e.g. when inductance and capacitance can be neglected) In some instances there are several...
I know nothing about fortran, but i wanna learn this programming language. Could you suggest or recommend the best way to do it?
Thanks for your comments
Does anyone has an idea about where i can find a manual of MG's Sepam 1000?
This relay seems to discontinuated so i have not been able to find information about it.
Thanks for your comments
I'm evaluating motors operating conditions in a factory
Does anyone know a method to calculate motor winding temperature (hot spot) based on motor operating current, voltage and ambient temperature?
If so, which motor parameters do i need? are those parameters easy to obtain from manufacturer...
What's exactly the meaning of a motor service factor?
Should this factor be multiplied to nominal current or power of the motor?
What are the advantages and disadvantages of operating a motor at its service factor rating?
Thanks for your comments
Wolud you mind installing an On Load Tap Changer in an existing 34.5/4/16 kV transformer to deal with voltage regulation problems instead of installing capacitor banks?
Potential problems with capacitors are resonance due to harmonics and switching transients. The only disadvantages with the...
I work for at a production facility for a petroleum company. We have an uninterruptible power supply UPS feeding an offices block (computers, printers, communication systems and so on). The UPS is supplied through a 480/208 D/y transformer (secondary solidly grounded plus neutral conductor). I...
