WMEA Presentation May 29, 2014
Managing Power Demand on Excavators
Craig V Fredrich– Engineering Technical Steward
Caterpillar Global Mining
ERS / DGL Product Group
Contents
Safety
Introduction
Caterpillar AC History
Robust Power Requirements
Power Demand Management
Summary
Questions
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Safety
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Safety First, Safety Always
Emergency Phone Numbers
•
CPR/AED Certified?
• Fire Emergency:
•
Who will call emergency numbers?
• Call 911
•
Room Hazards - Chairs
•
Location of Exits
•
Nearest Fire Extinguisher
•
Nearest AED
•
Evacuation Point
• Medical Emergency:
• Call 911
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Introduction
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Craig Fredrich
• Electrical engineer
• 28+ Years Mining experience
• Started in field service working on SCR based analog
machines
• Have been with the progression of the drive systems to the
present IGBT digital controls
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Caterpillar AC History
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37 YEARS CATERPILLAR AC EXPERTISE
Bucyrus forms alliance
with Siemens.
1976
Bucyrus introduces “GTO”
AC Drives
Electric Rope Shovels
Small Draglines
Large Draglines (Swing)
1980
Bucyrus introduces
“Analog SCR” AC Drives
Electric Rope Shovels
Small Draglines
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1989
Bucyrus develops first AC
IGBT/AFE Gearless
8750 Zhungeer (CHINA)
1999
Bucyrus introduces
“IGBT/AFE” AC Drives
495BII
Large Draglines (Swing)
2003-04
Bucyrus AC IGBT/AFE
Conventional Geared
8200 Reliance (INDIA)
8200 Reliance (INDIA)
2006-07
Bucyrus AC IGBT/AFE
Conventional Geared
8750 Lake Lindsay (AUS)
8750 TAU (CAN)
2010-14
IGBT AC Drive Systems
180 plus machines approaching 8,000,000 operational hours
IGBT powered Electric Rope Shovels operating since 1999
5 machines approaching 200,000 operational hours
IGBT powered Draglines operating since 1999
2 new machines
IGBT powered 8200 Draglines go to work 2014
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Robust Power Requirements
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Robust Power Requirements
• Electric Rope Shovels have a very high rate of change in
power demand
• To reduce energy costs, rope shovels also regenerate
electricity back onto the line
• A robust power system is
required to manage both
the regeneration and the
high ramp rates
• These requirements
provide challenges for
Diesel power systems
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Robust Power Requirements
• Rope shovel rate
of change are 2 to
3 times faster than
a typical Diesel
generator can
provide
• To protect the
generator from
regeneration,
resistive load
banks burn off
excess energy
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Power Demand Management
How it Works
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Power Demand Management – How it works
Peak Shaver
Shaves peak demand by using
energy stored in ultra capacitors
Power supplied by ultra caps
Ramp Rate Limiter
Redistribution of power for ideal
genset loading
Power stored in ultra caps
Dig
Swing & dump
Lower
Electric Rope Shovel Typical Power Demand
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Power Requirements with Power Management System
Peak Shaver
Shaves peak demand by using
energy stored in ultra capacitors
Ramp Rate Limiter
Redistribution of power for
ideal genset loading
Regeneration
Recharge ultra-capacitors with
energy from stopping motions
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Power Demand Management - On-Grid
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Intellectual Property – Power Demand Management
•
•
•
•
U.S. Patent No. 4,358,719
U.S. Patent No. 8,174,225
U.S. Patent No. 8,536,814
Future Patents Pending
8750-81 Dragline 8-8-10 Typical KW vs Time curve
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8750-81 Dragline 8-8-10 Typical KW vs Time curve
Peak Shaver
Shaves peak demand by using
energy stored in ultra capacitors
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Power Demand Management Overview
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Cat® Power Demand Management Technology
Caterpillar Exclusive Technology
Off-Grid Benefits
• Most efficient off-grid power solution available
– Shovel operational on 4MW of genset power for reduced fuel
consumption compared to traditional method of operating with
8MW of power or more
• Patented technology manages energy
– Rope shovel regeneration power utilized not wasted
• Sustainable solution
– Reduced greenhouse gas emissions
– Less wasted energy
Additional Benefits after Power Grid is in place
• Trail cable flexibility – longer trail cable runs
• Substation sizing – reduced power infrastructure costs
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Power Demand Management – Trail Cable Sizing
Longer trail cable* allows for more flexibility when placing
substations
• Keep substation
out of the pit
• Less hassle
relocating during
laybacks
• Remove the need
to run high
tension cable in
the pit
*Trail cable length is dependent
upon many factors, including
voltage drop of the transformer and
overhead line.
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Demonstrations at Tucson Proving Grounds
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Power Demand Management
Building Blocks
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System Components
Transformers
AFEs
Inverters
Hoist
Incoming
Power
Propel
Crowd
Swing
Chopper
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Energy Storage
Equipment Pictures
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MRC Features
Durable / Resilient Cabinets
Durable welded steel construction
Designed for ERS shock and vibration
environment
All components in cabinet are accessible for
maintenance
Degree of protection
Ventilated section IP21 in acc IEC 529
Non-ventilated section IP54 in acc IEC529
Ambient temperature
Normal Operation -40 °C to + 50 °C
Storage & Transportation -40 °C to +70 °C
Integrated and independent liquid cooling
system
Integral propel Transfer Switch
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AC Power Module Building Blocks
Dragline Skid Configuration
Space for up to four AFE rectifiers
Common DC bus
Aux Power
Precharge
Transformer
Delta / Wye
Ground
Fault
Protection
AFE 1
AFE 2
Hoist
Inv 1A
Hoist
Inv 1B
AFE 3
AFE 4
Crowbar
Connects AFE with inverters
Space for up to five motor inverters
to power
Maximum one 824AC hoist motor
Maximum one 824AC drag motor
Maximum one 822AC swing motor
Conventional 1370W (4-4-4)
Powered with 4 MRCs
Conventional 1370W (4-4-4)
Powered with 4 MRCs
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Swing
Inv 1
Drag
Inv 1A
Drag
Inv 1B
DC Link Capacitor
M
T
Swing Motor 1
M
T
M
T
Hoist Motor1
M
T
Drag Motor 1
Propel Motor 1
Power Demand Management
Power Problems / Application
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Genset Challenges
• Regen Absorption
– Avoid engine overspeed
• Peak Power Limiting
– Limit engine sizing
• Rate of Change
– Match engine dynamic response
• Application without Peakshaving can require double the
number of gensets needed with peakshaver
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Mine Power Considerations
• Unstable Power
– Mines experience machine downtime or component failure due
to insufficient or unreliable power infrastructure
• Delayed Power Plan
– Delays in the mine power plan cause delay in machine
production
• Pit Expansion
– Expanding to an area of the mine that does not have electrical
infrastructure
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Greenfield Mine Application
Mines have limited options for loading tools when opening
a new pit until electrical infrastructure is in place at the pit
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•
Diesel-powered machines are typically employed for initial
overburden removal
•
Operating electric rope shovels on
Diesel-generators is generally not
economical due to the machine’s
excessive rate of change in power
demand, unless peak shaving
technology is employed
•
Electric rope shovels also regenerate
electricity, which can not be absorbed
by generators and must be absorbed
by PDMS or burned off via load banks
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Mine Development with Diesel-Powered Machines
Pre-Stripping
Pros
+ Flexibility / Utility
+ Lower Initial Capital Cost per
machine
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Power Grid
Complete
Production
Cons
- Higher Cost / ton
- Lower NPV
- Higher Total Cost
Mine Development with Power Demand Management
Pre-Stripping
Pros
+ Lower Cost / ton
+ Longer machine life
+ Backup Generators
+ Best TCO
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Power Grid
Complete
Production
Cons
- Higher Initial Capital Cost
- Generator Cost
Holistic Machine Approach
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Holistic Machine Approach
CAT Total Machine Commitment
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Holistic Approach Examples
• House Ventilation Study
• Propel Study
• Roller Load Study
• Stability Study
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Questions?
THANK YOU
Close
Thank You For Your Participation
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