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Canal Operations and Automation. Bert Clemmens U.S. Arid-Land Agricultural Research Center UDSA-ARS Maricopa, Arizona, USA. What have we learned so far?. Steady-state backwater curves are useful for understanding how canal systems function. Downstream influences can be transferred upstream. - PowerPoint PPT Presentation
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Canal Operations Canal Operations and Automationand Automation
Bert ClemmensBert ClemmensU.S. Arid-Land Agricultural Research CenterU.S. Arid-Land Agricultural Research Center
UDSA-ARSUDSA-ARSMaricopa, Arizona, USAMaricopa, Arizona, USA
What have we learned so far?What have we learned so far?
Steady-state backwater curves are useful Steady-state backwater curves are useful for understanding how canal systems for understanding how canal systems function. Downstream influences can be function. Downstream influences can be transferred upstream.transferred upstream.
Free-flow structures and sections of Free-flow structures and sections of uniform flow (i.e., at normal depth) isolate uniform flow (i.e., at normal depth) isolate downstream influences from transferring downstream influences from transferring upstream.upstream.
Canal Operations are improved if Canal Operations are improved if operation of structure is simple.operation of structure is simple.
Things that simplify operations:Things that simplify operations: Good flow measurementGood flow measurement Free-flow structuresFree-flow structures long-crested weirslong-crested weirs
Things that complicate operationsThings that complicate operations Lack of flow measurementLack of flow measurement Uncertain structure hydraulics & operationsUncertain structure hydraulics & operations Intermediate, non-regulating structuresIntermediate, non-regulating structures
It is possible to determine wave travel It is possible to determine wave travel times for operations from steady-state times for operations from steady-state backwater curves (volume compensation)backwater curves (volume compensation)
Structure hydraulics have a big influence Structure hydraulics have a big influence on how waves travel through canal pools.on how waves travel through canal pools.
Canals under backwater and weirs provide Canals under backwater and weirs provide faster (and probably more predictable) faster (and probably more predictable) response times.response times.
Some things we didn’t coverSome things we didn’t cover
Typical operations can be considered Typical operations can be considered upstream control, since we want to keep upstream control, since we want to keep the water level on the upstream side of the water level on the upstream side of structures constant.structures constant.
Long-crested weirs are being promoted Long-crested weirs are being promoted because they reducing response times because they reducing response times and keep water levels more constantand keep water levels more constant
Automatic upstream level control is Automatic upstream level control is becoming more common.becoming more common.
Tail-Ender ProblemTail-Ender Problem
These approaches contribute to the tail-These approaches contribute to the tail-ended problem, where all the mismatches ended problem, where all the mismatches end up at the downstream end of the end up at the downstream end of the system.system.
Solving the Tail-Ender ProblemSolving the Tail-Ender Problem
Good measurement and accounting keep Good measurement and accounting keep right amount of water in canals and reduce right amount of water in canals and reduce the chance for serious mismatches.the chance for serious mismatches. This mean operators should keep track of and This mean operators should keep track of and
be accountable for mismatchesbe accountable for mismatches Remote manual operation can identify and Remote manual operation can identify and
correct the problem. (SCADA)correct the problem. (SCADA) New methods for automatic downstream New methods for automatic downstream
level control are being developed.level control are being developed.
Old canal systems were not designed for accurate measurement, control and
accounting Canal control is difficult because:
Upstream changes are delayed downstream Upstream changes arrive gradually Pool volumes change with discharge, roughness, and depth
at structure Canal operators want steady flows and rigid schedules
-- farmers want flexibility and responsiveness Common problems result
Flow rates fluctuate Flow rates may be too high or low Operations are unresponsive to needs Inadequate accounting for water entering and leaving canal
CAIDD SCADA – 109 sites
Manual Supervisory Control
Additional FeaturesAdditional Features Incremental ( Relative ) Gate Flow ChangeIncremental ( Relative ) Gate Flow Change Flow rate control at headgatesFlow rate control at headgates Check-Structure Flow Balance Showing Check-Structure Flow Balance Showing
Accumulated Downstream DemandsAccumulated Downstream Demands Routing of known demand changesRouting of known demand changes Pool-Volume Balance to Help Determine Flow Pool-Volume Balance to Help Determine Flow
MismatchesMismatches High/Low Water Level Limits Can Be Enforced High/Low Water Level Limits Can Be Enforced
Through Automatic Upstream Level ControlThrough Automatic Upstream Level Control
Flow Monitoring Standard Supervisory Control Features using Standard Supervisory Control Features using
iFix Dynamics from Intellution, Inc. (MSIDD)iFix Dynamics from Intellution, Inc. (MSIDD)
Flow Rate Control
Good Flow Measurement does not happen by Good Flow Measurement does not happen by accidentaccident
Check gates are usually not accurate Check gates are usually not accurate measurement gates – but good incremental flow measurement gates – but good incremental flow control is possiblecontrol is possible
Continuous monitoring of flows and/or levels/gate Continuous monitoring of flows and/or levels/gate position is requiredposition is required
Turnout flow monitoring usually is based on Turnout flow monitoring usually is based on assuming constant upstream water levelassuming constant upstream water level
Only applicable for headgates or for check gates Only applicable for headgates or for check gates under centralized controlunder centralized control
Incremental flow-rate control
iFix allows user-defined displays (CAIDD)iFix allows user-defined displays (CAIDD)
Software for Automated Canal Management -- SacMan
Main features include: Routing of known demand changes with
volume compensation (similar to Canal de Provence and CAP).
Automatic control of flow rate at key locations.
Distant downstream water level feedback control to account for
flow measurement errors, demand routing errors, & unknown disturbances.
Canal Automation Scheme
LocalControl
LocalControl
LocalControl
LocalControl
LocalControl
Central Observation and Control Water Demands
Water SupplyConstraints
Water SupplySchedule
Water DeliverySchedule
LocalControl
LocalControl
LocalControl
LocalControl
LocalControl
Central Observation and Control Water Demands
Water SupplyConstraints
Water SupplySchedule
Water DeliverySchedule
RTU
Operator
Personal Computer
iFix SCADASacMan
iFixModbus Driver
iFix SCADAMonitor & Control
SacManDemandDatabase
SacManOrder
SacManControl Program
iFixProcessDatabase-
Software for Automated Canal Software for Automated Canal Management -- SacManManagement -- SacMan
Components of control logicComponents of control logic
Feedforward controller
Setpoint
Flow controller
Feedback controller
Qff
Qfb
y
yy
e
PI Optimization with LQRPI Optimization with LQR
Multi-input multi-output optimizationMulti-input multi-output optimization
Retains PI format for understandabilityRetains PI format for understandability
Based on incremental flow controlBased on incremental flow control
Extensively tested through simulation and considerable real-time Extensively tested through simulation and considerable real-time
testingtesting
MPC optimization MPC optimization
Multi-input multi-output optimizationMulti-input multi-output optimization
Black box formatBlack box format
Based on incremental flow controlBased on incremental flow control
Some testing through simulation and limited real-time testingSome testing through simulation and limited real-time testing
Can handle a wider variety of constraintsCan handle a wider variety of constraints
Feedback control of Downstream Water LevelsFeedback control of Downstream Water Levels
SacMan Orders generates a schedule of flow changes
Flow changes are implemented by SacMan Control Program or printed for manual
operation
Pool Flow Balance
SCADA screen showsSCADA screen shows Actual flow at check structureActual flow at check structure Current downstream demand at check Current downstream demand at check
structurestructure Operator can examine differences Operator can examine differences
between actual and intended flows to between actual and intended flows to identify control (or measurement) issuesidentify control (or measurement) issues
Pool Volume Mismatches With steady inflow and outflow, changes in With steady inflow and outflow, changes in
pool water level indicate mismatches in net pool water level indicate mismatches in net inflow rate (inflow – outflow)inflow rate (inflow – outflow)
SCADA screen shows flow mismatchesSCADA screen shows flow mismatches Operators can use flow mismatches to Operators can use flow mismatches to
change flows between pools and route change flows between pools and route additional flow into the systemadditional flow into the system
If water level is low and declining, operator If water level is low and declining, operator needs to both increase flow and pool volume!needs to both increase flow and pool volume!
Note: these water-level based flow Note: these water-level based flow mismatches are meaningless when flow mismatches are meaningless when flow changes have recently been madechanges have recently been made
Software for Automated Canal Management
SacMan
Manual Local Central
Flow Monitoring
Flow Control
Demand Scheduling
Incremental gate flow changes
Out-of-Bounds control
Pool Volume Mismatches
Pool Flow Balance
Control start-up
Water-Level setpoint changes
Alarms
Overall Control Strategy
Reachable Goal of Current Canal Automation Product
Development Water orders are entered into computerWater orders are entered into computer SacMan routes flow changes through canal SacMan routes flow changes through canal
system based on volume compensationsystem based on volume compensation Canal operator opens turnout gate at prescribed Canal operator opens turnout gate at prescribed
timetime Water level errors are corrected with feedback Water level errors are corrected with feedback
control (new technology works!)control (new technology works!) Headgate and check gate flow controllers Headgate and check gate flow controllers
maintain flow balancesmaintain flow balances If needed, main canal pool volumes are used to If needed, main canal pool volumes are used to
balance secondary canal volume errorsbalance secondary canal volume errors
Maricopa-Stanfield Irrigation Maricopa-Stanfield Irrigation and Drainage District and Drainage District
(MSIDD)(MSIDD) Approximately 87,000 Approximately 87,000
Acres (35,000 Acres (35,000 Hectares )Hectares )
Construction Construction completed in 1987completed in 1987
Designed for Designed for supervisory control supervisory control with optional automatic with optional automatic downstream controldownstream control
WM LateralWM Lateral An excellent test facility for An excellent test facility for canal automation research!canal automation research!
90 cfs ( 2.5 m90 cfs ( 2.5 m33/s) capacity/s) capacity 5.4 miles (9 km) long5.4 miles (9 km) long 8 pools8 pools 10 turnouts (2 pumped)10 turnouts (2 pumped) 2 wells pumping in2 wells pumping in emergency spill in last poolemergency spill in last pool ultrasonic meters on turnoutsultrasonic meters on turnouts canal travel time less than 2 hourscanal travel time less than 2 hours Main canal can tolerate changes in WM inflowMain canal can tolerate changes in WM inflow
Typical Check StructureTypical Check Structure
Testing during 2004 & 2005Testing during 2004 & 2005
1)1) 30 day test period30 day test period2)2) 48 typical water orders48 typical water orders3)3) 2 atypical flow changes (power 2 atypical flow changes (power
outgages)outgages)4)4) Tested different upstream, LQR Tested different upstream, LQR
downstream control strategies and downstream control strategies and combinationscombinations
5)5) In 2005, tested Model Predictive ControlIn 2005, tested Model Predictive Control
Typical test scenarioTypical test scenario
Routine operations (full control)Routine operations (full control) Water orders entered into SacMan OrderWater orders entered into SacMan Order Schedule of gate flow changes madeSchedule of gate flow changes made Schedule posted to SacMan CPSchedule posted to SacMan CP SacMan CP changes flow setpointSacMan CP changes flow setpoint Check gate flow set every 2 minute Check gate flow set every 2 minute Operator delivers water to userOperator delivers water to user Feedback control adjustments every 10 Feedback control adjustments every 10
minutesminutes
Typical results- 2004Typical results- 20043 delivery changes routed automatically3 delivery changes routed automatically
PIPI++-1-1 downstream controller (80% cap), pool 5 under level control downstream controller (80% cap), pool 5 under level control
WM-0 July 17, 2004
0
5
10
15
20
25
30
35
40
6:00 9:00 12:00 15:00 18:00
Flo
w R
ate
(cfs
)
WM-1 July 17, 2004
2
2.5
3
3.5
6:00 9:00 12:00 15:00 18:00
Dep
th (
ft)
WM-2 July 17, 2004
2
2.5
3
3.5
6:00 9:00 12:00 15:00 18:00
Dep
th (
ft)
WM-3 July 17, 2004
2
2.5
3
3.5
6:00 9:00 12:00 15:00 18:00
Dep
th (
ft)
WM-4 July 17, 2004
2
2.5
3
3.5
6:00 9:00 12:00 15:00 18:00
Dep
th (
ft)
WM-5 July 17, 2004
2
2.5
3
3.5
6:00 9:00 12:00 15:00 18:00
Dep
th (
ft)
WM-6 July 17, 2004
2
2.5
3
3.5
6:00 9:00 12:00 15:00 18:00
Dep
th (
ft)
WM-7 July 17, 2004
2
2.5
3
3.5
6:00 9:00 12:00 15:00 18:00
Dep
th (
ft)
Feedback control of Feedback control of Downstream Water LevelsDownstream Water Levels
Multi-input multi-output optimizationMulti-input multi-output optimization
Retains PI format for understandabilityRetains PI format for understandability
Based on incremental flow controlBased on incremental flow control
Extensively tested through simulationExtensively tested through simulation
Research (2002) on WM canal identified capabilities and limitation of various downstream water-level controllers
Series of simple PI Controllers
More CentralizedPI+1
-1 Controller
Pool 2 -- Sept. 25
0.60
0.70
0.80
0.90
1.00
1.10
1.20
1.30
9.50 11.50 13.50 15.50 17.50 19.50
Time
Wat
er D
epth
(m
)
SOBEK Simulation
Field Test
Pool 2 -- Oct. 16
0.70
0.75
0.80
0.85
0.90
0.95
1.00
1.05
1.10
9.00 10.00 11.00 12.00 13.00 14.00
Time
Wat
er D
epth
(m
)SOBEK Simulation
Field Test
Feedback control tests 2004Feedback control tests 2004Simulated groundwater well failure PISimulated groundwater well failure PI++
-1-1 and PIL and PIL++--
More centralized controller spread out the disturbanceMore centralized controller spread out the disturbance
WM-0 July 30 & 31, 2004
0
5
10
15
20
25
30
18:00 21:00 0:00 3:00 6:00
Flo
w R
ate
(cfs
)
WM-1 July 30 & 31, 2004
2
2.5
3
3.5
18:00 21:00 0:00 3:00 6:00
Dep
th (
ft)
WM-2 July 30 & 31, 2004
2
2.5
3
3.5
18:00 21:00 0:00 3:00 6:00
Dep
th (
ft)
WM-3 July 30 & 31, 2004
2
2.5
3
3.5
18:00 21:00 0:00 3:00 6:00
Dep
th (
ft)
WM-4 July 30 & 31, 2004
2
2.5
3
3.5
18:00 21:00 0:00 3:00 6:00
Dep
th (
ft)
WM-5 July 30 & 31, 2004
2
2.5
3
3.5
18:00 21:00 0:00 3:00 6:00
Dep
th (
ft)
WM-6 July 30 & 31, 2004
2
2.5
3
3.5
18:00 21:00 0:00 3:00 6:00
Dep
th (
ft)
SummarySummary
SacMan can control a canal under full SacMan can control a canal under full automatic controlautomatic control
SacMan Order can effectively route SacMan Order can effectively route deliveries under manual or automatic deliveries under manual or automatic controlcontrol
Performance depends on canal Performance depends on canal propertiesproperties
Future PlansFuture Plans
Implementation at CAIDD (120 sites) is Implementation at CAIDD (120 sites) is ongoingongoing
SRP starting to test SacMan OrderSRP starting to test SacMan Order
New training tool for SCADA operators New training tool for SCADA operators and canal automation testing has been and canal automation testing has been developeddeveloped
USWCL Canal Control SystemUSWCL Canal Control System
Modbusover
RS-232 RTU
RTU
RTU
Modbusover
RS-232
Spread SpectrumRadio System
iFixUser Interface
iFixProcess
Database
SACMan
Off-line SCADA Training through SimulationOff-line SCADA Training through Simulation
Radio link sent to another computer that simulates RTU and Canal FlowRadio link sent to another computer that simulates RTU and Canal Flow
Sobek/Matlab
PhysicalSimulator
HardwareSimulator
iFix SCADA
Gate Positions/ChangesWater LevelsBattery VoltageModbus overRS-232
Gate PositionWater LevelsBattery VoltageXML-RPC overTCP/IP
Gate PositionsWaterlevelsTurnout FlowsXML-RPC overTCP/IP
Simulator Software
Sequence of Canal Automation Implementation
Step 1: Remote, manual monitoring and control, using SCADA system
Limitations: Rely on operator judgment. Wait-and-see approach. Hard to control large network. Transient flows are hard to control.
Sequence of Canal Automation Implementation
Step 2: Independent, automated control of individual gates based on local water levels
Central control within SCADA (e.g. SRP) Remote control with PLC (e.g. ITRC) or RTU.
Limitations: No coordination Failures not recorded or observed Tailender problems and spills Wrong level controlled?
Sequence of Canal Automation Implementation
Step 3:Centralized automated control, using SCADA
and computer-driven logic.
Limitations:• Accurate flow measurement or significant in-
canal storage required. • Controls average water level rather than
downstream water level (e.g. CAP).