modelThreeStateDynamic
Extends from TransiEnt.Components.Turbogroups.OperatingStates.PartialStateDynamic (State graph model with state-depentend maximum values and gradients).
Information
1. Purpose of model
Three state dynamic turbine model as state transition graph
2. Level of detail, physical effects considered, and physical insight
L1: Models are based on characteristic lines and / or transfer functions
A hysteresis has been added for the state change from halt to startup. Sometimes chattering can occur at this switch which can be avoided using the hysteresis.
Parameter 'MinimumDownTime' defines minimum time that power plant has to be shut down before beeing able to start up again.
3. Limits of validity
(no remarks)
4. Interfaces
P_set_star: input for electric power in W
P_set_star_lim: output for electric power in W
5. Nomenclature
(no remarks)
6. Governing Equations
(no remarks)
7. Remarks for Usage
slewRateLimiter: set P_grad_operating =-1, if slewRateLimiter is not needed.
8. Validation
Tested in check model "TestThreeStateDynamic" and "TestThreeStateDynamic_Initatmin"
9. References
(no remarks)
10. Version History
Model created by Pascal Dubucq (dubucq@tuhh.de) on 01.10.2014
Quality check (Code conventions) by Rebekka Denninger on 01.10.2016
Hysteresis for halt-startup change added by Carsten Bode (c.bode@tuhh.de) in Nov 2018
Model modified by Oliver Schülting (oliver.schuelting@tuhh.de) in Nov 2018: added Minimum Down Time
Model modified by Oliver Schülting (oliver.schuelting@tuhh.de) on April 2019: added option to deactivate slewRateLimiter, added minimum operation time
Model modified by Robert Flesch (flesch@xrg-simulation.de) in Feb 2021: set output to zero if shutdown is active - check if shutdown is complete by using the power input
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.Time | t_eps (from PartialStateDynamic) | 10 | Threshold time for transitions |
| Real | P_star_init (from PartialStateDynamic) | 0 | Power at startup (p.u.) |
| SI.Frequency | P_grad_inf (from PartialStateDynamic) | 1 | Numerical value for unlimited gradients during shutdown |
| SI.Time | T_thresh (from PartialStateDynamic) | simCenter.thres | Time constant of numerical element between saturation and gradient limiter |
| Real | Td (from PartialStateDynamic) | simCenter.Td | Time constant of derivative approximation in slew rate limiter |
| Boolean | useThresh (from PartialStateDynamic) | simCenter.useThresh | Use threshould for suppression of numerical noise |
| Real | thres (from PartialStateDynamic) | simCenter.thres | If abs(u-y)< thres, y becomes a simple pass through of u. Increasing thres can improve simulation speed. However to large values can make the simulation unstable. A good starting point is the choice thres = tolerance/1000. |
| SI.Frequency | P_grad_operating (from PartialStateDynamic) | 0.02/60 | Maximum Gradient during operation |
| Boolean | useSlewRateLimiter (from PartialStateDynamic) | true | choose if slewRateLimiter is activated |
| Boolean | useHomotopyVarSlewRateLim (from PartialStateDynamic) | simCenter.useHomotopy | true if homotopy shall be used in variableSlewRateLimiter |
| SI.Time | t_startup | 3600 | Startup time |
| SI.Time | t_min_operating | 0 | Minimum operation time |
| Real | P_min_operating | 0.3 | Minimum power (p.u.) |
| Real | P_max_operating | 1 | Maximum power (p.u.) |
| Boolean | smoothShutDown | true | shut down process will be smoothed - power gradient will be limit by 'P_grad_operating' |
| SI.Frequency | P_grad_startup | P_grad_inf | Maximum Gradient during startup |
| TransiEnt.Basics.Types.ThermalPlantStatus | init_state | if P_star_init < P_min_operating then 0 else 1 | State of plant at initialization |
| Real | thres_hyst | 1e-10 | Threshold for hysteresis for switch from halt to startup (chattering might occur, hysteresis might help avoiding this) |
| SI.Time | MinimumDownTime | 0 | Minimum time the plant needs to be shut down before starting again |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Blocks.Interfaces.RealOutput | P_grad_star_max_out (from PartialStateDynamic) | Relative maximum gradient in operation | |
| Modelica.Blocks.Interfaces.RealOutput | P_grad_star_min_out (from PartialStateDynamic) | Relative minium gradient in operation | |
| TransiEnt.Basics.Interfaces.Electrical.ElectricPowerIn | P_set_star (from PartialStateDynamic) | Connector of setpoint input signal | |
| TransiEnt.Basics.Interfaces.Electrical.ElectricPowerOut | P_set_star_lim (from PartialStateDynamic) | Limited output signal | |
| Basics.Interfaces.Electrical.ElectricPowerIn | P_actual_star (from PartialStateDynamic) | Connector of actual power |