The use of simulation in commissioning a hydropower generator

Transcription

1 BHA Summer Forum 2013 UWE Bristol The use of simulation in commissioning a hydropower generator Toni Jones Dewi Jones Sa ad Mansoor

2 The Dinorwig pumped storage hydroelectric scheme Located in north west Wales Commissioned in 1983, it remains one of the largest pumped storage hydro stations in Europe Total power output 1728MW and reservoir capacity of about 10GWh Working head of about 550m Six reversible Francis pump/turbines Six vertical axis 330MVA motor/generators Standstill to full power ( fast start ) < 90s Spin-in-air to full power <12s About 40,000 mode changes per year Grid balancing services Primary response: change in power output to help contain any frequency deviation that happens if there is a loss of load or generation on the Grid. Fast start reserve: machine is at standstill but can be brought on-line very quickly; Spinning reserve: machine is rotating synchronously but not producing active power; Regulating reserve: closed loop frequency control. What needs to be simulated? Run-up from standstill to generation or pumping Transition from spinning in air to generating or pumping Response to Grid frequency deviation

3 Role of the Governor Plant Water inflow Guide vanes Controlled water flow Turbine runner Mechanical power Generator Electrical power Control signal Governor Measured power Controller Industrial computer (PLC) Hardware + software Demanded power Automatic control or operator intervention Grid frequency error

4 Motivation Governor upgrade: Replace obsolescent technology; Install better communications and computing capability; Perform a complete revision and re-write of the software. Benefits of simulation Minimise the financial impact of Unit down-time during commissioning Differential wholesale price of electricity /MWh = 50 (day) - 30 (night) = 20. One Unit generating at 300MW for 8 hours -> 300 x 8 x 20 x ,000. This represents the potential daily saving of doing most of the commissioning on a Simulator while the Unit itself remains operational. Reduce the risk of defective implementation For high-value plant the overriding priority is to minimise any risk of damage during commissioning: Financial loss Physical damage Injury to personnel Solution: Dry-commissioning on a Simulator before Wet-commissioning on the Plant.

5 Real-time hardware-in-the-loop simulation Hardware-in-the-loop (HIL): Plant model in software Production software on target processor (such as a PLC) Electronic interface for I/O: analog, digital logic and frequency signals Real-time : Action of the software is synchronised to external events The software has to be temporally correct as well as logically correct A hardware-in-the-loop simulator replaces the Plant with a computer model which, to the Controller, is (ideally) indistinguishable from the Plant itself. Strategy: Connect the current Governor PLC to the Simulator Record reference responses for all modes of operation Replace the current Governor with new PLC hardware and software Perform dry commissioning : Test the new Governor on the Simulator and verify its responses against the reference records; correct as necessary until agreement is complete Proceed to wet commissioning of the new Governor

6 Simulator architecture Windows PC IDE Matlab/Simulink modelling Modeller GUI Data logging and post-processing dspace PX10 Simulator Real-time model execution Electronic interfaces Governor PLC Simulator GUI Governor PLC Execution of control functions Interface to Operator touch panel Operator touch panel Operator touch panel Monitoring Operator input

7 Grid: Model based on Grid dynamics obtained by system identification An overview of the computer model On-Plant Instrumentation: Sensors Condition detection and event generation Auto-synchronisation Plant: Hydraulics Guide vanes servo Turbine Motor/generator Blowdown VFSE Main Inlet Valve Sequencer: Extended state transition table for event handling Sequence control during mode changes

8 Modelling the hydraulics The hydrodynamics are represented by a distributed parameter model: the water hammer equations V 1 p dz f g V V 0 t x dx 2D a 2 V x p 0 t These are solved in real-time by the Method of Characteristics, for a very simple version of the hydraulic system. Modelling the pump/turbine Nonlinear 4-quadrant static characteristics derived from a turbine scale model during original development (late 60s and early 70s): o Unit flow v Unit speed o Unit torque v Unit speed Similitude relationships used for scaling effects of head and size of machine Real-time simulation model validated against an independent reference model

9 Modelling mode changes Generate Shutdown event: Operator mode select [~SD] /Start aux plant Spin/Gen Shutdown Wait for auxiliary plant to start event: Auxiliary plant running Spin/Pump Pump [P SP] /pulse spin relay on /pulse pump relay off [G SG] /pulse spin relay off /pulse pump relay off It was necessary to model part of the Plant sequence control in order to simulate mode changes. This was done using a state transition table. Wait for indicator relay etc

10 Graphical User Interface Real-time parameter editor Head, Frequency, Power, Guide Vane Opening Numeric display Load angle MIV opening Dewatering indicator Mode selection Simulation start/stop Simulation state Low frequency threshold Logic variables

11 Other potential uses for the Simulator Operator training Link to trading simulations to help tactical decision making Advanced methods for fault diagnosis Assessing advanced control techniques Exploring the benefits and drawbacks of: o modifying system parameters o introducing new equipment o changes in working practices. Conclusions A hardware-in-the-loop Simulator has been developed for the Dinorwig pumped storage hydroelectric station. It has proved highly effective as an aid to safe and rapid commissioning of a new Governor. For more, see: Improved governor response at the Dinorwig power plant Greg Yohe & Toni Jones Hydrovision International Denver, Colorado, July 2013.