Advanced Metering Tools for
Building Energy Use
Christopher Dent
DENT Instruments
541.388.4774
www.DENTinstruments.com
Columbia River Chapter
Association of Energy Engineers
October 8, 2012
Whom Am I?
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President of DENT Instruments, Inc.
Degrees in Astronomy, Physics,
Mechanical Engineering
Licensed Professional Engineer in
Mechanical and Electrical Engineering
Designer of DENT Products
In Energy Research since 1978
October 8, 2012
www.DENTinstruments.com
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Who Is DENT Instruments?
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Manufacturer of Metering and Data
Logging Products
Founded in 1988 in Bend, Oregon
20 Employees
Manufacturing in OR, TX, Asia & Europe
Customer Base Includes Utilities, Fortune
500, Governments, Military
30% of Sales Are International
October 8, 2012
www.DENTinstruments.com
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What Does DENT Make?
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Permanent Mount Meters –
PowerScout Series
Test & Measurement Meters –
ELITEpro SP (ESP), SMARTloggers
Meters are found on Aircraft Carriers,
Nuclear Submarines, Space Shuttle
Launch Platform, Elevators in the
Empire State Building, Electric Cars
In 50 States and on 7 Continents
October 8, 2012
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Electricity 101
What’s a Volt? What’s an Amp?
Meters only measure two things:
Volts & Amps. Everything else (kWh, PF,
VARs) is a mathematical construct.
 Think of a wire as a water hose
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Volts = the water pressure, psi
Amps = the water flow rate, gpm
October 8, 2012
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Electricity 101
What’s a Watt?
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Watts are Power and is the rate of
doing useful work
Watts = Instantaneous Volts X Amps
Watts can be thought of as heating
1,000 Watts = 1 Kilowatt (kW)
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KWHs are Energy and is the amount
of useful work done
October 8, 2012
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Electricity 101
What’s a VA?
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VA = V (true or rms) X A (true or rms)
(1,000 VA = 1 kVA
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1,000,000 VA = 1 MVA)
VA is not a “real” physical value, is not
measured directly, and must be calculated
VA includes power factor and harmonics.
VA is used to size wires and transformers
October 8, 2012
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Electricity 101
What’s a VAR?
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VAR = Volt-Amps Reactive
VARs are power (like kW) but
do no useful work
VARs occur in reactive systems,
e.g., motors, transformers, capacitors
VARs are “real” and can be measured
directly
VARs = Bad
October 8, 2012
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Electricity 101
What is Power Factor (PF)?
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Power Factor = Phase (time) Difference
Between the Volts and Amps
Power Factor = W / VA or W/√(W² + VAR²)
PF varies from -1 to +1 but is typically
~ -.9 to ~+.4 (Note: -.99 ≈ +.99!)
Two kinds of Power Factor:
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Displacement (Excludes Harmonics)
Apparent (Includes Harmonics)
October 8, 2012
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Electricity 101
Power Factor Cont’d.
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Low Power Factor (<.98 or so) = Bad
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Makes higher utility bills
Causes heating in wiring, motors, switch
gear, and transformers (“K Rated”)
Contributes to line losses in distribution
systems
Reduces capacity of distribution systems
October 8, 2012
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Electricity 101
What are Harmonics?
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Harmonics are “Noise” on the Electrical
System
Harmonics are caused by Non-Linear Loads
(Amps not proportional to Volts) that distort
the smooth Sine wave
Waveform distortions caused by Harmonics
predominantly occur on the current
waveform, not the voltage waveform
Harmonics are calculated using Fourier
Analysis
October 8, 2012
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Waveforms
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Sinusoidal Waveform – No Harmonics
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Non-Sinusoidal Waveform – With Harmonics
October 8, 2012
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Electricity 101
Power Parameter Relationships
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Power (right) Triangle
VA2 = W2 + VAR2
dPF = W/√(W2 + VAR2) “Displacement PF”
does not include Harmonic currents
aPF = W / VA (= Cosine Φ) “Apparent PF”
includes Harmonic currents
October 8, 2012
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Electricity 202
How Utilities Bill
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In Descending Frequency:
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Energy: Kilowatt-hours, kWh
Demand: Kilowatts, kW
Power Factor or VARs
Time-Of-Use: TOU kWh
Interval kWh
kVA or kVAh
October 8, 2012
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Average Rates By State
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Electricity 202
How Utilities Bill: Demand, kW
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Highest Average 15 Minute Draw (kW)
in the Month
Demand charges typically range from
20-40% of the total monthly bill of C&I
customers
Units are $/kW
October 8, 2012
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Electricity 202
How Utilities Bill: PF or VARs
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VARs do no useful work but,
VARs require larger wires, breakers,
service entrances, feeders,
transformers, etc. so,
Utilities bill for it
Sometimes also called “Power Factor
Penalty” charges
October 8, 2012
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Electricity 202
How Utilities Bill: TOU kWh
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Cost of providing energy is different at
different times of the day
Time-Of-Use billing takes that into
account
TOU rates can be daily (mid-day v.
night) or seasonal (summer v. winter)
Usually only for larger customers
(except in CA)
October 8, 2012
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Electricity 202
How Utilities Bill: Interval kWh
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Extreme version of TOU rates
Price of Kilowatt-Hours used changes
every 15, 30, or 60 minutes
Not real common yet (California, Int’l)
Advantage: Reflects the spot price of
electricity
Requires sophisticated metering (e.g.,
ELITEpro SP)
October 8, 2012
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Electricity 202
How Utilities Bill: kVAh
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KiloVolt-Amp Hours
Not very common (yet?)
New electronic meters can measure
Advantage is that kVAh includes
Harmonics and Power Factor as well
as kWh
October 8, 2012
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Electricity 303
Electrical Systems
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Common Voltages are:
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Low Voltage 110 – 480 V (measured directly)
Medium Voltage 4 kV – 24 kV (requires a PT)
High Voltage > 24 kV (requires a PT)
Common Currents are <5 to >5,000 A
(Usually measured with “current transformers” or CTs)
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Line Frequency is 60 Hz (cycles per second)
October 8, 2012
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Electricity 303
Electrical Systems
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Common Electrical Services are:
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1 Phase, 2 Wire (110V, Receptacle)
1 Phase, 3 Wire (110/220V Residential)
aka “Split Phase”
3 Phase, 3 Wire (208 or 480V
Commercial loads & motors) aka “Delta”
3 Phase, 4 Wire (208/120V Small Com &
480/277V Large Com & Industrial) “Wye”
October 8, 2012
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Electricity 303
Single Phase
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1 Voltage (Typically 110V between
L1 & N)
October 8, 2012
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Electricity 303
Three Phase Four Wire “Wye”
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2 Voltages: Phase to Phase or Phase
to Neutral, 480/277V or 208/120V,
120o Phase Shift
October 8, 2012
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Electricity 404
Metering: Basic Ideas
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There are only two items that can be
measured: Volts and Amps
Everything else is calculated by the
meter!
Voltages up to 600V are usually
measured directly
Voltages >600V are measured with
Potential Transformers (PTs)
October 8, 2012
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Electricity 404
Metering
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Current (Amps) can be measured
directly up to ~5 Amps in some meters
More often, Current is measured using
a Current Transducer or Current
Transformer (CT) that turns a
dangerous high current into a safe, low
voltage
October 8, 2012
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Electricity 404
Metering: Example CTs
October 8, 2012
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Electricity 404
Metering
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All Power Meters have inputs for both
(and only) voltage and current
Power meters internally compute Watts,
VARs, VA, and Power Factor
Power Meters have real-time clocks to
track when power is being used
Storing the values over time gives kWh,
kVARh, kVAh, and average PF
October 8, 2012
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Meters & Metering
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ELITEpro SP: A portable,
7 channel, interval recording,
polyphase power meter
Suitable for single
phase to 3 phase 4 wire
Power & Energy measurement
October 8, 2012
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ELITEpro SP Meter
PhaseChek™ Lights
Indicator
Lights for Two
Digital I/O
Ports
October 8, 2012
Communication/
Logging On Light
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ELITEpro SP
Panels for Bluetooth,
WiFi, Cell
communication options
October 8, 2012
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ELITEpro SP
Voltage
connections
October 8, 2012
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Setting Up The ELITEpro SP™
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Determine the voltage service type –
number of phases, number of wires,
voltage, current levels
Service type specifies the number of
CTs and voltage connections needed
October 8, 2012
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Setting Up The ELITEpro SP™
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Launch ELOG (software) and create a
Setup Table (Configuration File)
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Determine the data collection (integration)
interval
Determine and Configure the meter Channels
and Recording Parameters
Check that there is sufficient memory for the
recording time (Determine Length of Metering
Period)
October 8, 2012
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Setting Up The ELITEpro SP™
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Connect the Meter to PC with USB or RF
Set Logger Clock
Download Setup Table
October 8, 2012
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Setting Up The ELITEpro SP™
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Connect CTs to Load Wires—watch
orientation (Use Typical Setup Pics)
Connect ESP Voltage Leads
Use PC to view readings in real-time
and verify proper connections
Close comm connection with meter,
Disconnect PC cable from meter
October 8, 2012
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1 Phase 2 Wire Setup Table
October 8, 2012
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Connect Meter
October 8, 2012
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Display Real-Time Values
October 8, 2012
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Fun With Waveforms…
October 8, 2012
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…And Harmonics
October 8, 2012
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Retrieving Data From the ESP
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Connect the PC to the Logger using
USB or RF
Retrieve Data with
Specify a Data File Name and
Destination Folder or use defaults
October 8, 2012
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Sample Data File
October 8, 2012
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Making Sense of the Data
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ELOG Analysis Features
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Data File Trimming
Graphs
Summary Statistics
Special Analysis Features
Export the Data for Further Analysis
October 8, 2012
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Create A Graph
October 8, 2012
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The Real World:
Calculating Savings
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First, Understand the Electric Bill
Second, Measure All the Parameters In the
Bill
Third, Collect Energy Data Before and After
any Energy Conservation Measure (ECM)
Fourth, Use ELOG to Download and Filter
the Data
Fifth, If Needed, Export the Data to Excel for
Additional Analysis
October 8, 2012
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Tips & Tricks
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Always Verify Installation Before Leaving the
Site!
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Use Real-Time Values Display
Do the Numbers Make Sense?
Compare to External References
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Digital Voltmeters (DVM)
Clamp-on Ammeters (e.g., Amprobe)
Clamp-on Power Meters (e.g., Fluke 41)
AutoPoll program for unattended data
downloads (included with ELOG)
October 8, 2012
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Safety
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Rubber Gloves with Leather Outer
Shell
“One Hand, One Wire”
Rubber Mat
Goggles
Especially 480V Systems (or higher)!
Try to Stuff the meter inside the
Cabinet and Close It
October 8, 2012
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Permanent Metering
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PowerScout 3, 18, 24, 48
Multi-Circuit Monitoring
Meters are meant to be left at the site
indefinitely
Usually part of a Building EMS or
Controls System
Sometimes standalone
October 8, 2012
www.DENTinstruments.com
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Typical Customers
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Wal-Mart, Walgreens, Wendy's
Large C & I
Military Bases & Government
Shopping Malls
Multi-Tenant Commercial Buildings
Apartments
October 8, 2012
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PowerScout 3 Single
& PS18 Multi-Circuit Monitor
October 8, 2012
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Survey Tools
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Non-Contact, Time-Of-Use, Status
Loggers
SMARTLoggers
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TOU-L LightingLogger
TOU-M MagLogger
TOU-CT CT Logger
TOU-C Contact Logger
Low-Cost, Simple, Good Accuracy
October 8, 2012
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Survey Tools - SMARTloggers
October 8, 2012
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TOU-L LightingLogger
October 8, 2012
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That’s It!
Thank you!
October 8, 2012
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