Hello All,

I'm hoping someone may have some insight into a problem I've been wrestling with for a while now. In attempting to calibrate a model, I've run into a rather complex operational control for a group of storage reservoirs that all service a single, large, pressure zone. In essence, the control methodology works like so:
  • At regular intervals, the system calculates the average level of the three storage reservoirs.
  • If a storage reservoir is currently above the average level an altitude valve at the reservoir is automatically adjusted to close slightly (dependent on the % difference), allowing less water to enter the reservoir.
  • If a storage reservoir is currently below the average level, the altitude valve at the reservoir is automatically adjusted to open slightly (again, dependent on the % difference), allowing more water to enter the reservoir.
  • This comparison is conducted every few minutes. If at any time one altitude valve is opening, another should be closing.


Would anyone have any thoughts about representing this system in a model? If it is even possible to be done without introducing dummy reservoirs, I imagine it is through the rule based controls, but the logic for getting the level average is escaping me. Any assistance is greatly appreciated.

Thank you!