1.07 Overcoming Hydraulic Issues Using a Hydro Power ...
Transcript of 1.07 Overcoming Hydraulic Issues Using a Hydro Power ...
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
Jean-Louis DROMMIElectricite de France
Paper Number 1.07
Session 1
15 November 2017
Overcoming Hydraulic Issues Using
Variable Speed Drive
in a Hydro Power Scheme
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
Overlook
• SUMMARY
– EDF overseas
– Hydraulic waterway issues
– Overcoming the hydraulic timelag
– Example of simulated case
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
EDF world wide
• Electricité de France
– Major player in France and in Europe
– Also abroad (Renewable USA, Laos, …)
– And French overseas regions
• Reunion island in Indian Ocean with a large share of hydro
generation that
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
Hydro a century old renewable
• Hydraulic waterway issue
– Hydro usually seen as flexible and quick
• In comparison to thermal
– But managing water energy must consider hydrodynamicphenomena
• Water inertia T = L Q / A g H
• Cavitation
– The case study key numbers :
• Waterway length : 4800m pennstock
• Water head : 440m
• Power : 2 units 28MW each
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
Reunion Island Hydro electric project
• The Reunion Island Hydro Scheme– Long penstock
– No surge tank
• Very challenging hydraulic condition– Tw = 5,1s
• Water hammer mitigation– Slow niddle speed
• Avoid penstock material fatigue– Water head
oscillation must be limited below +/-15%
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
Island grid code requirement
• Specific dynamic requirement for primary reserve
• Twice faster than continental Europe
• Can’t be achieved naturally
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
Hydraulic issues
• Overcoming hydraulic time lag and head
oscillation
– Usual practice is to install a surge tank
– Or very seldom, to install pressure tanks
– Or to innovate… with power inverter interfacing
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
Fully fed variable speed
• Full inverter interface, voltage source type
• And its model : pseudo continuous type
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
SIMULATION TOOL
• SIMSEN– On the shelf tool
• Developped by– EPFL
– Since early 1990s
• Used by severalmanufacturers
• Can perform hydro electric transientsimulation– Interaction can be
detected
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
Inverter control
• In house control strategy : generator side
– Active load adjusts the torque
– Reactive load can be set to zero
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
Inverter control
• In house inverter control : grid side
• Follow up strategy for active load
• Reactive load supplied to grid
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
100% load ramp up
• Some results: unit loading 100%
Release of kinetic energy
Very fast electric response; power delivered to grid
Follows the set point ramp
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
Load Ramp down 20% 15 sec
• Load ramp down 20%
Release of kinetic energy
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
Load Ramp up 20% 15 sec
Release of kinetic energy
Release of kinetic energy
Waterway lag time
Storage of kinetic energy
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
Influence of rotor inertia : 1, 2 or 3 times
Speed deep reduction with higher inertia
But longer stabilization time
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
To conclude momentarily and probe further
• Implementing power converters allows
to increase unit dynamic behavour
– May be of interest to reduce hydro scheme
cost
– Or to develop hydro sites not suitable with
standard technology
• Making use of rotating kinetic energy
– Acts as a temporary energy storage
– Using batteries would probably offer similar
service
– The higher the inertia, not the better
Electricity Supply to Africa and Developing Economies: Challenges and Opportunities
To probe further
• Simulation must be undertakenwith other types of turbine
– Francis
– Pump Turbine
• Using power converter introducesfurther opportunities
– Permanent voltage support withSTATCOM function
– Fast speed ramp up using converter as booster
– And many others yet to come …