PVsyst's forum

Welcome on PVsyst's forum.
It is currently Wed Sep 23, 2020 2:12 pm

All times are UTC+02:00




Post new topic  Reply to topic  [ 3 posts ] 
Author Message
PostPosted: Thu Jan 18, 2018 5:54 pm 

Joined: Wed Jun 07, 2017 4:48 pm
Posts: 14
Hello Fellow PVSyst Modelers!

I have a (hopefully) quick question regarding using the default values for multiple transformers in a system.

For example, I have the following system:
Module Strings > DC Combiner > Inverter > Unit Transformer > GSU Transformer (at substation) > (Meter) > Transmission grid tie-in.

My colleagues and I have determined how to use the Ohmic losses Detailed Computation to obtain loss fractions at STC for each of those stages separately, which we then add together outside of PVSyst and put the sum of the losses in the DC or in AC as applicable.

On the external transformer, there are two in the system: the Unit transformer, and the GSU transformer.

Assuming that we have the constant loss and inductive losses at STC for both, can we enter the sum of these losses for both the unit transformer and the GSU in the corresponding fields in the "External Transformer" section?

Extending that, in case we do not have such detailed information, can we use double the default values?

Is this approach accurate?

Thank you,
Link


Top
   
PostPosted: Fri Jan 26, 2018 11:16 pm 
User avatar

Joined: Mon Apr 16, 2012 7:29 pm
Posts: 1680
In the present time, PVsyst only allows to define a simple output circuit, with one transformer.
The loss is expressed in terms of percentage of the Peff (corresponding to STC) value.
Now if you have several transformers, the easiest way id to simply add the ohmic loss (in terms of percentage) of the first and the second transformer.

Working explicitly on the resistance of the transmission lines is also possible, but more complex. You should define an "equivalent" resistance (as "seen" from the output of the inverters) of the circuits before the first transformet, between both transformers and up to the injection point, taking the voltage ratios into account.


Top
   
PostPosted: Fri Aug 24, 2018 6:27 pm 

Joined: Wed Jun 07, 2017 4:48 pm
Posts: 14
Thanks for that reply. I've tried to implement it in a worksheet that I use parallel to PVSyst.


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 3 posts ] 

All times are UTC+02:00


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Limited