Default Structure List into Pipe Network

[ricardo_moraes_EGC]

How can I change the default value from Null Structure into EGC-PV in the Structure List of a Pipe Network

 

[hippe013]

Can you clarify your question and post a larger version of you screen shot? The image is too small to see. 

[ricardo_moraes_EGC]

I want to default to EGC-PV in the Structure List, rather than Null Structure, so that whenever I create a pipe network I don't have to change from null structure to EGC-PV