The Simulation Time dialog box allows you to change the settings related to hydraulic time step at which an Extended Period Simulation is to be analyzed.
An Extended Period Simulation (EPS) is a hydraulic model run that evaluates system hydraulics and other analysis for a duration greater than a single hydraulic time step (i.e., Steady State). Many features of InfoWater Pro including SCADA, Energy Management, Water Quality are dependent upon a hydraulic model analyzed over a series of time steps (i.e., Extended Period Simulation). If you select the Steady State check box, then only a steady state model will be analyzed. A Simulation Time setting can be created for a specific scenario within InfoWater Pro.
To create, modify, or delete a Simulation Time setting, you can open up the Simulation Options dialog box from the Operation tab of the Model Explorer or from the Simulation Time's Browse button in the Run Manager.
Steady State Simulation
A steady state simulation (SS) does not involve time steps. It is a model run that encompasses a single snapshot of the water system as it pertains to demands, pumping data, and tank elevations.
As a result, steady state simulations do not allow you to see the big picture of what may, or may not, be occurring in a distribution system. For example, tanks cycling, water age, energy consumption, etc. While a steady state simulation does not provide this information, for some water systems (particularly closed systems with non-fluctuating demand), a steady state simulation is more than adequate.
Extended Period Simulation
An extended period simulation (EPS) is any modeling run that evaluates system hydraulics for a duration greater than a single hydraulic timestep (steady state). You are provided with many tools in InfoWater Pro that allow customization of an EPS simulation.
Many features of InfoWater Pro including SCADA, Energy Management, Water Quality, and Logic Rules are dependent upon a model being analyzed over a series of timesteps (Extended Period Simulation).
Simulation Time Options
When performing an EPS, many modeling parameters are dependent on analysis timesteps (intervals) and duration. The following durations and time steps may be specified:
- Duration – Total length of a simulation in hours. Use 0 to run a single period (snapshot) hydraulic analysis.
- Hydraulic Timestep – Time interval between re-computation of system hydraulics. Normal default is 1 hour.
- Pattern Timestep - Time interval used with all time patterns. Normal default is 1 hour.
- Quality Timestep – Time interval between routing of water quality/temperature constituent. Normal default is 5 minutes (0:05 hours). It is important for a water quality/temperature analysis that this value be no greater than 1/10 the hydraulic timestep.
- Report Timestep – Time interval between times at which computed results are reported. Normal default is 1 hour.
- Rule Timestep - Time interval for which Rule Based Logic Control rules are evaluated. For greater accuracy, use a rule timestep that is 1/10 the hydraulic timestep.
- Pattern Start - Hours into all time patterns at which the simulation begins (e.g., a value of 2 means that the simulation begins with all time patterns starting at their second hour). Normal default is 0.
- Report Start - Hours into simulation at which computed results begin to be reported. Normal default is 0.
- Start Clocktime - Clock time (e.g., 7:30 am, 10:00 pm) at which simulation begins. Default is 12:00 am (00:00 - midnight).
Once a simulation time is created, it can be associated with any scenario you specified or evaluated at any time via selection from the Run Manager.