unilhexio Posted October 16, 2012 Share Posted October 16, 2012 Hi!I have detected the following possible bug: when exporting to a file the Energy injected into Grid (hourly data) I obtain these values (for example):30/11/1990 4:00 030/11/1990 5:00 030/11/1990 6:00 030/11/1990 7:00 13796530/11/1990 8:00 44176130/11/1990 9:00 68336130/11/1990 10:00 86694630/11/1990 11:00 113108830/11/1990 12:00 82455430/11/1990 13:00 44496330/11/1990 14:00 36495730/11/1990 15:00 43090130/11/1990 16:00 13510130/11/1990 17:00 -3247.810230/11/1990 18:00 030/11/1990 19:00 030/11/1990 20:00 0namely, there are values below zero although "night disconnect" is marked in external transformer detailed losses (ohmic losses). This occurs randomly and always in the beginning and final hours of a day. I have realized this problem at least from version 5.57.Moreover, the total sum of Energy Injected into Grid including negative values, is employed in order to calculate the performance ratio and the specific production of the PV Plant.Is this a real Bug or am I doing something wrongly?Kind regards. Link to comment Share on other sites More sharing options...
André Mermoud Posted October 16, 2012 Share Posted October 16, 2012 This negative value is rather low (around 0.3% of Pmax)The simulation is performed on a complete hour, and therefore also the "Night disconnect" function. Now in for one hour the PV production doesn't compensate the iron loss of your transformer, you can have a negative balance over the whole hour. Link to comment Share on other sites More sharing options...
unilhexio Posted October 17, 2012 Author Share Posted October 17, 2012 Thanks for you reply, André. Link to comment Share on other sites More sharing options...
Mike_R Posted October 18, 2012 Share Posted October 18, 2012 I have a similar issue (energy injected into the grid) except for every off hour that should be outputting zero, it outputs -1128. The output looks like this:Year Hour Output90 0:00 -1128.173990 1:00 -1128.173990 2:00 -1128.173990 3:00 -1128.173990 4:00 -1128.173990 5:00 -1128.173990 6:00 -1128.173990 7:00 -1128.173990 8:00 7282990 9:00 16509290 10:00 25838590 11:00 33080790 12:00 31193390 13:00 20916790 14:00 13395090 15:00 54034 Link to comment Share on other sites More sharing options...
André Mermoud Posted October 20, 2012 Share Posted October 20, 2012 You have defined Transformer losses. When connected to the grid, the transformer consumes some energy (iron losses), explaining this night negative energy. You have the opportunity of disconnecting the transfo during the periods when the inverter is OFF (in the rreality, this means a HV automatic switch on the grid). Link to comment Share on other sites More sharing options...
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