How can I use a pressure reducing valve in the hydraulic model controlling the pressure at a control node? In water supply systems, we often automate valves to communicate with a critical point, instead of controlling the outlet pressure (pressure to, ppstream). But in WateGEMS only the pumps have this function. How do I keep a pressure fixed on a junction with a PRV? Considering that I have several scenarios with different demands, so using patterns is not a way.
Hi Eduardo,
I found this Wiki article which I believe speaks to the issue you are having - Modeling PRV / PSV controlled by pressure at remote location in the model
Please see if it answers your question but if not, we might need to get a copy of your model for analyis.
Thank-you,Larry Abla
Hi, Larry. Thank you for the reply.This article is exactly what I'm talking about. However, it explains the problem but does not explain a solution.The only part that leads to a solution is this part: "you can develop a relationship between demand in the zone and TCV setting". I understand that there is no solution for what happens on the operation. It talks about a PLC but doesn't show how I represent this in the model.Can I only do this with a "trick" using TCV?In my model I have 72 PRV that operates like this in field. I don't think that send it to you will finds a way. I can built a hypothetical model as a test, when diferents demand in results in the same pressure in a specific node.
Eduardo Fernandes said:This article is exactly what I'm talking about. However, it explains the problem but does not explain a solution.
The article proposes a possible workaround to address this situation and explains why it may not be practical to have this in a real system.
Eduardo Fernandes said:The only part that leads to a solution is this part: "you can develop a relationship between demand in the zone and TCV setting". I understand that there is no solution for what happens on the operation. It talks about a PLC but doesn't show how I represent this in the model.Can I only do this with a "trick" using TCV?
The article is based on advice that our Dr. Tom Walski provided, to help another user a few years ago, here: Modelling active control for PRV
I have updated the article with some more details based on what I believe Dr. Walski was suggesting, plus the other idea I had posted in the above thread. Please also see these papers which Dr. Walski worked on:
The conclusion in these papers is that a conventional PRV is good enough in most cases, while remote control costs more and is subject to instability.
Regards,
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.