Trolley Assist

May 3, 2023 VE ALVARADO 1

TROLLEY ASSIST TO OPTIMISE HAULING CYCLES WITH ELECTRIC TRUCKS

VICENTE ALVARADO, MEE, PRENG, GCCENGINEERING CONSULTANT+27 (0)83 377 9663+27 (0)14 763 [email protected]

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

VE ALVARADO 2May 3, 2023

TROLLEY ASSIST : What is it?


An engine drives the alternator to generate

power on board of the truck. The power is channelled 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 HPWheels Motors : 3100 HP

COMPARATIVE DUTY Acceleration On Flat On ramp DieselRetarding

Trolley

ENGINEHeavy Mild Heavy Low Low

WHEELMOTOR

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

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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

Loading

Flat

Flat

Flat

Flat

Diesel

Trolley

Retarding

Empty

Tipping

Retarding

Loaded

TRUCK SPEED (730E)


Truck : 730EElectric Drive : Statex III, MW GE 788; Alternator GE GTA-22Gross Weight : 715 000 lbPayload : 185 TonneRolling Radius : 68.4 (40.00R57)Gear Ratio : 26.816Engine GHP : 2700Grade : 8% Ramp + 2% RR

715000 lb • 10% • 68.4 inMotor Torque = = 15193 ft.lb 12 in/ft • 26.816 500 rpm • 60 min/hr • 2 • π • 67.2 in Truck Speed in Diesel = = 12.0 KPH 26.815 • 39380 in/Km 975 rpm • 60 min/hr • 2 • π • 67.2 in Truck Speed in Trolley = = 23.4 KPH 26.815 • 39380 in/Km

Weight of Trolley Gear on board ~3

Tons

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Motor Torque on Diesel Motor torque on Trolley @ 1600 Volts Torque versus Amperers @ 1600 volts 730E 2xMotor Torque @ 10% ER

SPEED - TORQUE CURVESTATEX III. VARI - VOLT TRUCK SYSTEM

EQUIPMENT :2 -GE788FS MOTORIZED

WHEELS1- GTA22H ALTERNATOR2400 RPM MAX

ARMATURE SPEEDIMPROVED FIELD

FUNCTION

BASED ON 2000 GHP/1850 NHP INPUT FOR TRACTION AT 1900 ENGINE RPM

Source : GE Transportation Systems

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.

0.33 lb/BHP-Hr • 2025 BHPFuel 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

USE OF ENERGY IN TROLLEY MODE


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 Usage = 1600 * 1450 / 1000 = 2320 KW

TRUCK TROLLEY PERFORMANCE MEASUREMENT


Truck 25343 Performance Test

Type: Komatsu 730ECapacity: 185 TonGVW: 324.3 Ton

Truck PerformanceOperation Index Unit Test 1 Test 2 Test 3 Test 4 Test 5 Test 6 Test 7 Test 8

Complete TestDate 01/08/2002 01/08/2002 01/08/2002 01/08/2002 01/08/2002 01/08/2002 01/09/2002 01/09/2002Start 12:25:28 9:56:04 10:31:16 11:01:46 11:40:29 12:46:32 10:32:33 10:15:31Finish 12:44:58 10:28:08 10:57:45 11:37:20 12:16:13 13:25:33 10:53:12 10:31:12Duration 0:19:30 0:32:04 0:26:29 0:35:34 0:35:43 0:39:01 0:20:39 0:15:41Fuel Used Lts 42.91 37.38 34.63 44.66 60.92 73.45 37.08 51.93Travel Km 9.075 7.921 7.660 8.252 9.185 14.121 7.329 5.731

Acceleration Time sec 93.7 88.6 88.8 46.2(Fully Loaded) Total Fuel Lts 4.13 4.35 3.39 1.87

Travel Km 0.756 0.592 0.492 0.173

Idling Time sec 885.1 625.7 1060.9 1017.2 477.9 118.5Fuel Consump Lts 5.08 4.32 8.23 7.53 5.64 1.78Av. Fuel ConsumpLph 20.67 24.86 27.92 26.65 42.51 54.12

On Flat Road Time sec 341.1 293 357.9 402 614.1 631.9 455 78.5Fuel Consump Lts 14.54 11.07 14.64 16.51 24.73 24.46 20.04 2.48Travel Km 3.460 3.026 3.728 4.218 6.187 6.582 3.195 0.571Av. Fuel ConsumpLph 153 136 147 148 145 139 159 114Av. Truck Speed Kph 36.5 37.2 37.5 37.8 36.3 37.5 25.3 26.2

On Ramp Diesel Time sec 78.3 44.4 22.2 40.8 205.2 124.4 50.3 374.4Fuel Consump Lts 8.03 4.57 2.25 4.04 21.86 12.92 5.21 39.43Travel Km 0.429 0.236 0.112 0.196 1.063 0.660 0.256 2.063Av. Fuel ConsumpLph 369 371 364 357 383 374 373 379Av. Truck Speed Kph 19.7 19.1 18.1 17.3 18.7 19.1 18.3 19.8

In Trolley Mode Time sec 89.2 178.9 146.1 140.4 176.9 234.8Fuel Consump Lts 1.25 1.69 1.16 1.50 2.43 1.88Travel Km 0.602 1.248 1.029 0.919 1.166 1.498Energy KWHr 52 102 78 79 97 117Av. Fuel ConsumpLph 50 34 29 39 49 29Av. Truck Speed Kph 24.3 25.1 25.4 23.6 23.7 23.0Av. Energy UsageKW 2085 2050 1923 2024 1973 1800

In Retarding Time sec 258.3 214.6 162.6 149.1 174.6 284.1 253.4 256.8Fuel Consump Lts 2.71 2.41 1.90 1.81 2.00 3.16 3.52 3.00Travel Km 1.358 1.717 1.412 1.222 1.471 1.992 1.946 1.715Av. Fuel ConsumpLph 38 40 42 44 41 40 50 42Av. Truck Speed Kph 18.9 28.8 31.3 29.5 30.3 25.2 27.6 24.0

Loaded Empty

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-1500

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-500

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1 1448 2895 4342 5789 7236 8683 10130115771302414471

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Idling

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Window Trolley

Window Retarding

Ramp Diesel

On Flat

EVALUATION OF THE TROLLEY ASSIST SYSTEM (730E Performance)


Payload 185 Tonne

Condition Idling Flat road On Ramp DieselIn Trolley ModeFlat road Idling Flat road Retarding Flat road CycleLoading Loaded Loaded Loaded Loaded Tipping Empty Empty Empty Summary

Distance in [m] 800 400 1000 200 200 1400 200

Performance with TrolleySpeed [KPH] 0 35.1 12.0 23.4 35.1 0 35.1 26.4 35.1Fuel Rate[LPH] 30.2 144.1 360.0 45.0 144.1 30.2 86.4 44.2 86.4E. Rate [KW] 0 0 0 2320 0 0 0 0 0

Time [sec] 360 82 120 154 21 300 21 191 21 1268Fuel [Lts] 3.0 3.3 12.0 1.9 0.8 2.5 0.5 2.3 0.5 27Energy [KWHr] 0 0 0 99.1 0 0 0 0 0 99Truck Productivity TPH 525Hauling Variable Energy and Fuel Cost @ Fuel $806.52/Klt and Energy $57.81/MWHr $27.42Performance only in DieselSpeed [KPH] 0 35.1 12.0 12.0 35.1 0 35.1 26.4 35.1Fuel Rate[LPH] 30.2 144.1 360.0 360.0 144.1 30.2 86.4 44.2 26.5E. Rate [KW] 0 0 0 0.0 0 0 0 0 0

Time [sec] 360 82 120 300 21 300 21 191 21 1415Fuel [Lts] 3.0 3.3 12.0 30.0 0.8 2.5 0.5 2.3 0.2 55Energy [KWHr] 0 0 0 0.0 0 0 0 0 0 0Truck Productivity TPH 471Hauling Variable Energy and Fuel Cost @ Fuel $806.52/Klt and Energy $57.81/MWHr $44.06

EVALUATION OF THE TROLLEY ASSIST SYSTEM EH4500 Performance


Payload 255 Tonne

Condition Idling Flat roadOn Ramp Diesel

In Trolley Mode Flat 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 TrolleySpeed [KPH] 0 36.1 13.5 25.4 36.1 0 36.1 27.0 36.1Fuel Rate[LPH] 34.0 199.9 499.8 46.4 199.9 34.0 119.9 30.5 119.9E. Rate [KW] 0 0 0 3600 0 0 0 0 0

Time [sec] 360 80 107 142 20 300 20 186 20 1235Fuel [Lts] 3.4 4.4 14.8 1.8 1.1 2.8 0.7 1.6 0.7 31Energy [KWHr] 0 0 0 141.7 0 0 0 0 0 142Truck Productivity TPH 744Hauling Variable Energy and Fuel Cost @ Fuel $806.52/Klt and Energy $57.81/MWHr $33.46Performance only in DieselSpeed [KPH] 0 36.1 13.5 13.5 36.1 0 36.1 27.0 36.1Fuel Rate[LPH] 34.0 199.9 499.8 499.8 199.9 34.0 119.9 30.5 18.3E. Rate [KW] 0 0 0 0 0 0 0 0 0

Time [sec] 360 80 107 267 20 300 20 186 20 1359Fuel [Lts] 3.4 4.4 14.8 37.0 1.1 2.8 0.7 1.6 0.1 66Energy [KWHr] 0 0 0 0.0 0 0 0 0 0 0Truck Productivity TPH 675Hauling Variable Energy and Fuel Cost @ Fuel $806.52/Klt and Energy $57.81/MWHr $53.19

THE RELIABILITY OF THE SYSTEM


Grootegeluk MineTrolley Lines UtilisationPeriod 1-Jan-2010 to 31-Dec-2010

2010 Trucks Total Distance (km)

Distance Travelled under Trolley Line (km)

Distance Trolley Line Used (km)

Tons Percentage Trolley Line Utilisation

Percentage Mean Utilisation

Truck Hrs in Trolley Mode

Fuel Saved KLt Energy Consumed MWHr

Jan-10 211078.88 7723.30 6871.42 301193.20 89.0% 3.3% 317.71 123.65 711.7Feb-10 209242.23 5787.89 4930.83 409792.90 85.2% 2.4% 238.09 88.73 533.3Mar-10 209054.46 7693.01 6850.65 801588.40 89.1% 3.3% 316.46 123.28 708.9Apr-10 185765.07 8055.06 7071.03 751563.90 87.8% 3.8% 331.35 127.24 742.2May-10 206531.72 5720.13 4978.73 232587.69 87.0% 2.4% 235.30 89.59 527.1Jun-10 222627.31 4504.57 4036.79 107336.80 89.6% 1.8% 185.30 72.64 415.1Jul-10 238910.58 6893.42 5537.46 647305.19 80.3% 2.3% 283.57 99.64 635.2Aug-10 218020.67 7606.85 5803.46 4560898.10 76.3% 2.7% 312.92 104.43 700.9Sep-10 232184.09 7079.06 5637.98 4284124.49 79.6% 2.4% 291.20 101.45 652.3Oct-10 223278.96 6621.00 5059.15 4492604.56 76.4% 2.3% 272.36 91.04 610.1Nov-10 215613.72 10392.36 7334.51 6642102.98 70.6% 3.4% 427.50 131.98 957.6Dec-10 221179.91 14539.48 10249.61 8982075.48 70.5% 4.6% 598.10 184.44 1339.7

Total 2593487.60 92616.13 74361.62 32213173.69 3809.86 1338.11 8534.09

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INCREMENTAL CAPITAL REQUIREMENTS FOR TROLLEY ASSIST SYSTEM

COST OF HAULERS TROLLEY OPTION•~10% HAULER COST

COST OF DC OVERHEAD LINE• LINE HARDWARE ( PROPORTIONAL TO LENGTH)• POINT OF SUPPLIES ( AV. NUMBER OF TRUCKS CONNECTED)

COST OF MAKE THE POWER AVAILABLE•ABOUT 3 MW REQUIRED PER CONNECTED TRUCK


THE COST OF THE DC OVERHEAD LINE


CAPITAL OPERATIONALOverhead DC Line:

Length of Ramp to Electrify and the type of Line. ~ $360 000 per Km (Exxaro Line)

Overhead DC Line:

Equivalent to 0.06 metres of CW per each Km of trolley ride.

Rectifiers and DC Supply:

Number of Supply Points (Average Number of trucks connected to the line)~ $715 000 per point

Additional Maintenance Cost of Equipment on board:

Equivalent to the cost of a Pantograph (>$10 000) every 20 000 Km of Trolley Ride

AC Feeder :Distance to suitable source(2300 to 3600 kW per truck connected to the line)

CONCLUSION


THANK YOU AND QUESTIONS


Engineering

Trolley Assist