How can we properly model Synchronous condensor in ETAP.
Explanation: I have modelled one line diagram of a power facility, and leave the synchronous condenser in the form of Panel only, and then perform the arc flash.
Now client is asking for modeling of each syncronous generator. We have 4 synchronous generators in the facility. I have to model them in the whole one line diagram and then again perform the arc flash study. Can anyone help me in this regard?
Another thing is can you please tell me, what percentage of short circuit current that synchronous generator feeds into the fault location....or during the short circuit. I have searched a lot and found that it contributes 2% short circuit current in the power system. How much this info is valid??
Regarding the first point, you just need to place each synchrounus machine in the model, then to edit the operation mode of each of them. During this task, you will find a good help written in bottom bar of the ETAP. I suggest you to read the ETAP help, and to watch the online webinars on its website.
Regarding the second point i.e the short circuit current contributions, you need to run the short circuit analysis of system with all components added to the model. The value various according to the generator parameters, operating point, system structure, initial conditions... etc.
Thanks Bandi Mallikarjuna Reddy
for the answer. Actually there is no option availble in Etap to use Generator as a condenser.The only option available in ETAP is to use Motor as a condenser. Can I use Motor as a condenser???
A synchronous condenser is like a synchronous generator, however, they are usually installed to provide bus voltage control / reactive power; they do not provide active power. So, the best way for you to model these condensers is to attribute the bus to which they are connected to as a "slack bus" meaning a bus which either the voltage is set or the reactive power is set.
Your load flow / short-circuit study has to consider each and every synchronous generator/condenser with their proper reactances (X"d, X'd, X'q, Xd, Xq) and time constants (for short-circuit); besides that, all induction motors 45 kW and above have to be considered in the short-circuit as a source whose reactance is its starting reactance. Short-circuit currents are determined considering all these sources and the infinity bus of the system which supply the facility.
Hi,
I guess it's so straight forward. See me in my office at Aug 22, 2018 on 8:30 am. I'll try to make sure to be there to help you out.
cheers
Synchronous motors load the power line with a leading power factor. This is often useful in cancellingout the more commonly encountered lagging power factor caused by induction motors and other inductive loads. Originally, large industrial synchronous motors came into wide use because of this ability to correct the lagging power factor of induction motors.The synchronous condenser may then be filled with hydrogen to aid cooling and reduce windage losses. Since the density of hydrogen is 7% of that of air, the windage loss for a hydrogen filled unit is 7% of that encountered in air. Furthermore, the thermal conductivity of hydrogen is ten times that of air. Thus, heat removal is ten times more efficient.
You can go for synchronous generator/condenser option with proper time constants as well as reactances. But probably you need to set a power limit by keeping in mind the short circuit currents limitations and heat management in the module. Good Luck
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