TROLLEY ASSIST TO OPTIMISE HAULING CYCLES WITH ELECTRIC TRUCKS By Vicente E. Alvarado Planning and Development Engineer Grootegeluk Coal Mine
PURPOSE OF THE PRESENTATION This presentation discuss the basic analytical tools required to evaluate the feasibility of the application of TROLLEY ASSIST to mining hauling cycles. By applying trolley assist, open cast mining activities may save up to 50% in the fuel cost and improve the productivity of the fleet by 10% or more
INTRODUCTION
TROLLEY ASSIST : What is it? An engine drives the alternator to generate power on board of the truck. The power is chenneled to the wheel motors Power is collected from a DC overhead line by means of pantographs. The line propels the truck. The engines just idle along Power Capacity in a 185 Tonne Truck: Engine : 2000 HP Wheels Motors : 3100 HP COMPARATIVE DUTY Accelaration On Flat On ramp Diesel Retarding Trolley ENGINE Heavy Mild Heavy Low Low WHEEL MOTOR Mild Low Mild Heavy Heavy
THE OVERHEAD LINE The overhead line consists of galvanised mast poles positioned at a maximum distance of 50 m apart. The line is strung with grooved contact wire, which may be fixed directly to the poles by means of insulated brackets or may hang from a messenger cable, which is fixed to the poles by means of insulators.
THE TRACTION RECTIFIERS The rectifiers are sized to supply one truck permanently. In this way, the number of trucks to be connected simultaneously to the line determines the number of rectifiers to supply a specific line. This distributed scheme reduces the possibility of overloading the contact wire and reduces the voltage fluctuations experienced by the truck 1500 DC Current [Amps] 6000 5000 4000 3000 2000 1000 0 4 3 2 1 0 0 100 200 300 400 500 Number of Trucks 1250 1000 750 500 j 250 0 1700 1660 Time [s e] 1620 1580 1540 1500
THE PERFORMANCE PARAMETERS OF THE TRUCK Speed Productivity Rate of Fuel Consumption Hauling Cost Energy Utilisation Rate Cost of Use of Electric Energy } They depend on the operational conditions of the truck Trolley Flat Retarding Loaded Flat Loading Flat Diesel Flat Retarding Empty Tipping
TRUCK SPEED Truck : EH4500 Electric Drive : Siemens AC Drive Gross Weight : 960 000 lb Payload : 255.4 Tonne Rolling Radius : 67.2 in Gear Ratio : 35.816 Engine GHP : 2700 Grade : 8% Ramp + 2% RR 960000 lb 10% 67.2 in Motor Torque = = 7505 ft lb 2 12 in/ft 35.816 Motor Torque [ ftlb ] 26000 24000 22000 20000 18000 16000 Motor Torque Curves - EH4500 Euclid-Hitachi/Siemens AC Haul Truck Drive Propel, Diesel Retard, Normal Propel, Trolley 10% Grade DC Link Voltage, (on Trolley): 2200 V @ 1500 A(max) 14000 12000 10000 8000 6000 4000 2000 0 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600 800 rpm 60 min/hr 2 π 67.2 in Truck Speed in Diesel = = 14.1 KPH 35.815 39380 in/km 1450 rpm 60 min/hr 2 π 67.2 in Truck Speed in Trolley = = 26.1 KPH 35.815 39380 in/km Motor Speed [ rpm ]
FUEL CONSUMPTION RATE In trolley mode, the engine normally idles at about 750 rpm. In that condition, the load on the engine is mainly the cooling blower of the electrical system. This load is normally about 10% of the gross capacity of the engine. In diesel propulsion on a 10% effective grade, the engine will develop full power at maximum speed. In the case of the 12V 4000 engine, this is 2025 BHP at 1900 rpm. ENGINE IN TRUCK 730E 0.33 lb/bhp-hr 2025 BHP Fuel Rate in Diesel = = 360 LPH 1.86 lb/l 0.41 lb/bhp-hr 2025 BHP 10% Fuel Rate in Trolley = = 45 LPH 1.86 lb/l
Energy Utilisation in Trolley For the EH4500 truck, the maximum line voltage is limited by the capacity of the system specified by Siemens at 2400 volts maximum at the DC link of the drive. The current is limited at 1500 A. Therefore the estimated energy utilisation of the EH4500 truck in trolley mode is 3600 kw. 730E Truck Motorised Wheel Curves For the 730E Truck: Energy Utilisation = 1600 * 1450 / 1000 = 2320 KW
Truck Performance Measurements Truck 25343 Performance Test Type: Komatsu 730E Capacity: 185 Ton GVW: 324.3 Ton Truck Performance Operation Index Unit Test 1 Test 2 Test 3 Test 4 2000 Performance Test on 730E Truck 48 Complete Test Date 01/08/2002 01/08/2002 01/08/2002 01/08/2002 Start 12:25:28 9:56:04 10:31:16 11:01:46 Finish 12:44:58 10:28:08 10:57:45 11:37:20 Duration 0:19:30 0:32:04 0:26:29 0:35:34 Fuel Used Lts 42.91 37.38 34.63 44.66 Travel Km 9.075 7.921 7.660 8.252 Acceleration Time sec 93.7 88.6 (Fully Loaded) Total Fuel Lts 4.13 4.35 Travel Km 0.756 0.592 Idling Time sec 885.1 625.7 1060.9 Fuel Consump Lts 5.08 4.32 8.23 Av. Fuel ConsumpLph 20.67 24.86 27.92 On Flat Road Time sec 341.1 293 357.9 402 Fuel Consump Lts 14.54 11.07 14.64 16.51 Travel Km 3.460 3.026 3.728 4.218 Av. Fuel ConsumpLph 153 136 147 148 Av. Truck Speed Kph 36.5 37.2 37.5 37.8 On Ramp Diesel Time sec 78.3 44.4 22.2 40.8 Fuel Consump Lts 8.03 4.57 2.25 4.04 Travel Km 0.429 0.236 0.112 0.196 Av. Fuel ConsumpLph 369 371 364 357 Av. Truck Speed Kph 19.7 19.1 18.1 17.3 In Trolley Mode Time sec 89.2 178.9 146.1 140.4 Fuel Consump Lts 1.25 1.69 1.16 1.50 Travel Km 0.602 1.248 1.029 0.919 Energy KWHr 52 102 78 79 Av. Fuel ConsumpLph 50 34 29 39 Av. Truck Speed Kph 24.3 25.1 25.4 23.6 Av. Energy UsageKW 2085 2050 1923 2024 Volts - Am ps - LP 1500 1000 500 0 1 1448 2895 4342 5789 7236 8683 10130115771302414471-500 -1000-1500 36 24 12 0-12 -24-36 KPH MW current in Amps Trolley cur in Amps Trolley volt in volt Fuel cons. in LPH Idling Truck speed in Km/h Window Trolley Window Retarding Ramp Diesel On Flat In Retarding Time sec 258.3 214.6 162.6 149.1 Fuel Consump Lts 2.71 2.41 1.90 1.81 Travel Km 1.358 1.717 1.412 1.222 Av. Fuel ConsumpLph 38 40 42 44 Av. Truck Speed Kph 18.9 28.8 31.3 29.5 Loade d Empty -2000-48
EVALUATION OF THE TROLLEY ASSIST SYSTEM Payload 185 Tonne Condition Idling Flat road On Ramp DiesIn Trolley ModFlat road Idling Flat road Retarding Flat road Cycle Loading Loaded Loaded Loaded Loaded Tipping Empty Empty Empty Summary Distance in [m] 800 400 1000 200 200 1400 200 Performance with Trolley Speed [KPH] 0 35.1 12.2 23.7 35.1 0 35.1 26.4 35.1 Fuel Rate[LPH 30.2 144.1 367.0 37.4 144.1 30.2 86.4 44.2 86.4 E. Rate [KW] 0 0 0 1930 0 0 0 0 0 Time [sec] 360 82 118 152 21 300 21 191 21 1265 Fuel [Lts] 3.0 3.3 12.0 1.6 0.8 2.5 0.5 2.3 0.5 27 Energy [KWHr 0 0 0 81.5 0 0 0 0 0 82 Truck Productivity TPH 527 Performance only in Diesel Speed [KPH] 0 35.1 12.2 12.2 35.1 0 35.1 26.4 35.1 Fuel Rate[LPH 30.2 144.1 367.0 367.0 144.1 30.2 86.4 44.2 26.5 E. Rate [KW] 0 0 0 0.0 0 0 0 0 0 Time [sec] 360 82 118 295 21 300 21 191 21 1408 Fuel [Lts] 3.0 3.3 12.0 30.1 0.8 2.5 0.5 2.3 0.2 55 Energy [KWHr 0 0 0 0.0 0 0 0 0 0 0 Truck Productivity TPH 473
EVALUATION OF THE TROLLEY ASSIST SYSTEM Payload 255 Tonne Condition Idling Flat road On Ramp DiesIn Trolley ModFlat road Idling Flat road Retarding Flat road Cycle Loading Loaded Loaded Loaded Loaded Tipping Em pty Empty Em pty Summ ary Distance in [m] 800 400 1000 200 200 1400 200 Performance with Trolley Speed [KPH] 0 36.1 16.0 31.5 36.1 0 36.1 27.0 36.1 Fuel Rate[LPH 34.0 199.9 499.8 46.4 199.9 34.0 119.9 30.5 119.9 E. Rate [KW] 0 0 0 3377 0 0 0 0 0 Time [sec] 360 80 90 114 20 300 20 186 20 1190 Fuel [Lts] 3.4 4.4 12.5 1.5 1.1 2.8 0.7 1.6 0.7 29 Energy [KWHr 0 0 0 107.3 0 0 0 0 0 107 Truck Productivity TPH 771 Performance only in Diesel Speed [KPH] 0 36.1 16.0 16.0 36.1 0 36.1 27.0 36.1 Fuel Rate[LPH 34.0 199.9 499.8 499.8 199.9 34.0 119.9 30.5 18.3 E. Rate [KW] 0 0 0 0 0 0 0 0 0 Time [sec] 360 80 90 225 20 300 20 186 20 1301 Fuel [Lts] 3.4 4.4 12.5 31.2 1.1 2.8 0.7 1.6 0.1 58 Energy [KWHr 0 0 0 0.0 0 0 0 0 0 0 Truck Productivity TPH 706
THE RELIABILITY OF THE SYSTEM Dispatch PowerView - Panto Utilization (Fleet) Haulpak 730E Euclid EH4500 Euclid EH3500 Total P. Fleet Total Actual Util Total Actual Util Total Actual Util Total Actual Util Aug-08 8019104 6174416 77% 746419 508819 68% 4397335 3430061 78% 13162858 10113296 77% Sep-08 7856927 6275095 80% 1011703 742567 73% 3960866 3191251 81% 12829496 10208913 80% Oct-08 6140578 4912127 80% 1005292 741819 74% 3602549 2878114 80% 10748419 8532060 79% Nov-08 6928293 5701496 82% 696260 501402 72% 3897195 3217586 83% 11521748 9420484 82% Dec-08 9163884 7296450 80% 1670151 1153852 69% 4466117 3431860 77% 15300152 11882162 78% Jan-09 9657243 7750729 80% 2182507 1521806 70% 5138075 4167920 81% 16977825 13440455 79% Feb-09 6744504 5685332 84% 1665515 1268863 76% 4160781 3525916 85% 12570800 10480111 83% Mar-09 6477716 5501435 85% 1675983 1242466 74% 3640241 3059834 84% 11793940 9803735 83% Apr-09 May-09 Jun-09 Jul-09 TROLLEY UTILISATION AT GROOTEGELUK MINE 100% 90% 80% 70% 60% Aug-08 Sep-08 Oct-08 Nov-08 Dec-08 Jan-09 Feb-09 Mar-09 Apr-09 May-09 Jun-09 Jul-09
CONCLUSION
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