Drives in Power Generation

Transcription

1 Franz Frank ABB Switzerland Mauricio Rotella ABB Chile Drives in Power Generation September 3, 2010 Slide 1

2 Agenda Power generation hot topics Energy saving with VSDs Power generation segments with VSD applications VSD applications in thermal power plants Pump and fan control with VSDs VSD applications in gas turbine power plants VSD applications in pump storage power plants References Energy savings case example September 3, 2010 Slide 2

3 Energy Value Chain Energy Efficiency: Improvement Targets Useful energy net energy transport 50% conversion efficiency line losses production process motor efficiency Primary energy Electrical energy Transmission & Distibution Industrial Plant Motors & Drives Buildings Energy input September 3, 2010 Slide 3 Energy use

4 Power generation hot topics Global warming and choice of primary energy sources Rising fuel costs CO2 emissions (trading, capturing, storage?) Nuclear power on the rise again Profitability Minimize costs of production, necessity to raise efficiency Growing energy demand Ageing of existing plants ( requirement for overhaul, upgrade, expansion) Requirement for new plants September 3, 2010 Slide 4

5 Three items to focus on 1. Alternative primary energy sources (wind, solar, biofuel etc.) 2. Capture and storage of CO 2 3. Increasing the efficiency of the conversion process for saving energy resources and reducing the CO 2 emissions. September 3, 2010 Slide 5

6 Energy saving through variable speed drives Electrical auxiliary consumption in a coal fired power plant 5-10% of the produced power is dedicated to electrical auxiliary consumption in the power plant (i.e. losses ) Processes driven by electric motors typically consume 80% of this electricity 20% Electric motors 80% Others (heating, lighting etc.) dedicated to processes driven by electric motors By applying electrical variable speed drives (VSDs), total losses can be reduced by ~20% In an 800 MW power plant there exists a reduction potential of >8 MW September 3, 2010 Slide 6

7 Power generation segments with MV VSD applications Applications soft starters for variable speed drives for Segments THERMAL (Solid fuelled) - feedwater pumps, condensate pumps, FD and ID fans, district heating pumps THERMAL GAS Turbine gas turbine (LCI.ST) feedwater pumps HYDRO Pump Storage hydro turbines of pumped storage power plants (LCI.SO) - September 3, 2010 Slide 7

8 Thermal power plant Pump applications Aux. consumption of a thermal PP: 5-10% Boiler recirc. pump kw Cooling water pump kw Boiler feed pump kw Feed water booster pump Condensate pump kw September 3, 2010 Slide 8

9 Power demand Throttling control versus VSD control Throttling H 2 = 1,27 H 1 = 1 VSD Control H 1 = 1 Design Point H 2 = 0,64 Design Point Q 2 = 0,7 Q 1 = 1 Q 2 = 0,7 Q 1 = 1 P 0.7*1.27 = 0.89 P 0.7* 0.64 = 0.45 September 3, 2010 Slide 10

10 Energy Efficiency of Pump Control Methods Pump Control P o w er D em an d Flow Bypass Control Throttling Control Hydro Coupling VSD Control Theoretical Power Demand Energy savings potential of VSD Control versus Throttling Control September 3, 2010 Slide 11

11 Thermal power plant Fan applications Gas recirc. fan kw Coal pulverizer fan kw Induced draft fan (booster) kw See notes for add l info Force draft fan kw September 3, 2010 Slide 12 Primary air fan secondary air fan kw Induced draft fan kw

12 Performance of a fixed speed fan with damper control Fan Characteristic Design Point / TB (Test Block condition) various contingency factors considered Fan Efficiency Levels Pressure 25% Flow Reduction Efficiency drop from 85.3% to 40% 45% losses Operating point / MCR (Maximum Continuous Rating) System Characteristic Damper Positions Flow Rate September 3, 2010 Slide 13 The power demand for the TB rating is significantly larger than for the MCR with the MCR rating being between 60 and 75 percent of the TB rating. [IEEE Std ]

13 Performance of a variable speed controlled fan Fan Efficiency Levels Design Point / TB Pressure 25% Flow Reduction Efficiency drop from 89% to 87% 2% losses Fan Characteristic depending on Motor/Fan Speed System Characteristic Flow Rate September 3, 2010 Slide 14

14 Energy Efficiency of Fan Control Methods Fan Control Po w er R eq u ired Outlet Damper Control Inlet Guide Vane Control Electrical VSD Control Theoretical Power Demand Flow Energy savings potential of VSD Control versus Damper Control September 3, 2010 Slide 15

15 Power generation segments with MV VSD applications Applications soft starters for variable speed drives for Segments THERMAL (Solid fuelled) - feedwater pumps, condensate pumps, FD and ID fans, district heating pumps THERMAL GAS Turbine gas turbine (LCI.ST) feedwater pumps HYDRO Pump Storage hydro turbines of pumped storage power plants (LCI.SO) - September 3, 2010 Slide 16

16 Combined-cycle power plant applications (HRSG) Boiler feed pump kw Aux. consumption of a CCPP: 3-4% Boiler recirc. pump kw Condensate pump kw Cooling water pump kw Fuel-gas booster compressor kw Co-Generation (COGEN) District heating recirc. pump kw September 3, 2010 Slide 17

17 Gas turbine starter Starting Frequency Converter (SFC) Megadrive LCI.ST Load Commutated Inverter topology, using thyristor semiconductors Proven technology > 750 units delivered Air cooled design Sequential starting of several generators possible with one single LCI.ST LCI.ST September 3, 2010 Slide 18

18 How does a Start-up work? Start-up sequence Break away and ramp-up to about 30% speed GT (and HRSG) purging Continue ramping up and GT ignition Continue ramping up in field weakening, GT gradually taking over Turn-off SFC Turn on main excitation Synchronize to grid September 3, 2010 Slide 19

19 Power generation segments with MV VSD applications Applications soft starters for variable speed drives for Segments THERMAL (Solid fuelled) - feedwater pumps, condensate pumps, FD and ID fans, district heating pumps THERMAL GAS Turbine gas turbine (LCI.ST) feedwater pumps HYDRO Pump Storage hydro turbines of pumped storage power plants (LCI.SO) - September 3, 2010 Slide 20

20 Pumped storage power plant In a pumped storage the water is flowing through the turbine and the machine is generating when demand is high. When demand is low and electricity is cheap the generator (running as motor) drives the turbine, pumping water back into the reservoir Starting frequency converter needed to start-up the generator/motor September 3, 2010 Slide 21

21 Application: LCI soft starter for 4 generators/motors September 3, 2010 Slide 22

22 Agenda Power generation hot topics Energy saving with VSDs Power generation segments with VSD applications VSD applications in thermal power plants Pump and fan control with VSDs VSD applications in gas turbine power plants VSD applications in pump storage power plants References Energy savings case example September 3, 2010 Slide 23

23 Case example Helsinki Energy, Finland Retrofit of fixed-speed motors with ACS 1000 VSDs, operating four boiler feedwater pumps (FWPs), each 4500 kw Benefits: Improved power plant efficiency (as FWPs are one of the biggest energy consumers in a power plant) Reduced maintenance costs September 3, 2010 Slide 24

24 Case example University of Illinois power plant, USA An US university power plant installed a 1,000 hp ACS 1000 MV drive for its scrubber booster fan Energy efficiency improved by 25% against that of inlet vanes Energy saving: about kwh/year Reduction of CO 2 emissions: kg/year Other benefits Better process controllability Less maintenance by soft starting No more start-up problems September 3, 2010 Slide 25

25 Case example Grosskraftwerke Mannheim, Germany Refurbishment of the 280 MW boiler at block 6 of the GKM power plant Retrofitting 2 of 3 boiler feedwater pumps with ACS 1000 VSDs, by replacing the old hydraulic couplings (with poor efficiency) ABB scope of supply: 2 x water cooled ACS 1000 VSD incl. dry type transformers, 4000 kw General overhaul and star-delta reconnection of the 6kV motors Benefits: percent energy savings: around MWh/year Fully containerized solution Reduction of CO2 emissions: t/year September 3, 2010 Slide 26

26 New reference Grosskraftwerke Mannheim, Germany New 900 MW coal fired power station (Block 9) in the city of Mannheim Customer s goal: all major motors to be VSD controlled in order to optimize plant efficiency ABB scope of supply: 2 x 70% feedwater pumps ACS 5000W, rated for 21.5MW induction machines 12 x ACS 1000 in the power range of 800kW to 3000kW for - condensate pumps - cooling water pumps - district heating pumps - coal pulverizer fans September 3, 2010 Slide 27

27 New reference ESKOM Medupi Power Plant New 4800 MW coal fired power plant, consisting of 6 blocks Variable speed driven condensate extraction pumps (each consiting of 6 blocks) 6 x air cooled ACS 5000 with integrated transformer, each 1800 kw Medupi construction progress April 2009 (source: Medupi construction progress Dec (source: September 3, 2010 Slide 28

28 New reference ESKOM Majuba, Kendal, Matimba Power Plant LCI refurbishment project for 3 coal fired 4000 MW power plants, each consiting of 6 blocks 6 x 3 feedwater pumps 6000rpm) per power plant 22 x LCI drives order ABB high speed machines, WMT 630 September 3, 2010 Slide 29

29 New reference Mühleberg Switzerland / Nuclear Power Plant Refurbishment project, replacing two LCI feed water pump drives, 3.4 MW / 3000 rpm, delivered in 1987/88 2 x LCI feedwater pump drives, 3.4 MW 1 x ACS 5000 additional pump drive, 3.4 MW 2 x ACS 1000 reactor circulation pump drives, 1.1 MW September 3, 2010 Slide 30

30 Agenda Power generation hot topics Energy saving with VSDs Power generation segments with VSD applications VSD applications in thermal power plants Pump and fan control with VSDs VSD applications in gas turbine power plants VSD applications in pump storage power plants References Energy savings case example September 3, 2010 Slide 31

31 Payback of applying electrical variable speed drives Case example Feedwater pump, average operating time / year = h Average electrical power consumption = 4 000kW Resulting electrical energy demand = MWh Energy savings due to applying VSD = 20% Resulting energy savings per year = MWh Energy cost savings = EUR based on el. energy costs of 5 ct/kwh resulting in a payback time of only two years total savings over 20 years lifetime = EUR Additionally! Reduction of CO2 emissions of ~5 000 t/year September 3, 2010 Slide 32

32 Lifetime costs of a VSD system 20 years total lifetime costs 92% Total investment costs < 6 % of the total lifetime costs Customer benefit: Big savings on energy consumption, not on investment costs 2% 6% Energy costs Investment costs Maintenance and overhaul costs September 3, 2010 Slide 33

33 Power Generation Energy Efficient Design of Auxiliary Systems in Fossil Fuel Power Plants September 3, 2010 Slide 34

34 September 3, 2010 Slide 35