Electro Industries Shark 200 User manual

V.1.24
March 15, 2018

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Doc# E149701 i
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Shark® 200/200T Meter Installation and Operation Manual Version 1.24
Published by:
Electro Industries/GaugeTech (EIG)
1800 Shames Drive
Westbury, NY 11590
Copyright Notice
All rights reserved. No part of this publication may be reproduced or transmitted in
any form or by any means, electronic or mechanical, including photocopying, record-
ing, or information storage or retrieval systems or any future forms of duplication, for
any purpose other than the purchaser's use, without the expressed written permission
of Electro Industries/GaugeTech.
© 2018 Electro Industries/GaugeTech
Shark® is a registered trademark of Electro Industries/GaugeTech. The distinctive
shapes, styles, and overall appearances of all Shark® meters are trademarks of
Electro Industries/GaugeTech. Communicator EXTTM and V-SwitchTM are trademarks
of Electro Industries/GaugeTech.
Modbus® is a registered trademark of Schneider Electric, licensed to the Modbus
Organization, Inc.

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Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
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Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Customer Service and Support
Customer support is available 9:00 am to 4:30 pm, Eastern Standard Time, Monday
through Friday. Please have the model, serial number and a detailed problem descrip-
tion available. If the problem concerns a particular reading, please have all meter
readings available. When returning any merchandise to EIG, a return materials
authorization number is required. For customer or technical assistance, repair or
calibration, phone [phone] or fax [phone].
Product Warranty
Electro Industries/GaugeTech (EIG) warrants all products to be free from defects in
material and workmanship for a period of four years from the date of shipment.
During the warranty period, we will, at our option, either repair or replace any product
that proves to be defective.
To exercise this warranty, fax or call our customer-support department. You will
receive prompt assistance and return instructions. Send the instrument, transporta-
tion prepaid, to EIG at 1800 Shames Drive, Westbury, NY 11590. Repairs will be made
and the instrument will be returned.
This warranty does not apply to defects resulting from unauthorized modification,
misuse, or use for any reason other than electrical power monitoring. The Shark®
200/200T meter is not a user-serviceable product.
THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED
OR IMPLIED, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABIL-
ITY OR FITNESS FOR A PARTICULAR PURPOSE. ELECTRO INDUSTRIES/
GAUGETECH SHALL NOT BE LIABLE FOR ANY INDIRECT, SPECIAL OR
CONSEQUENTIAL DAMAGES ARISING FROM ANY AUTHORIZED OR
UNAUTHORIZED USE OF ANY ELECTRO INDUSTRIES/GAUGETECH
PRODUCT. LIABILITY SHALL BE LIMITED TO THE ORIGINAL COST OF
THE PRODUCT SOLD.

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Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Use Of Product for Protection
Our products are not to be used for primary over-current protection. Any protection
feature in our products is to be used for alarm or secondary protection only.
Statement of Calibration
Our instruments are inspected and tested in accordance with specifications published
by Electro Industries/GaugeTech. The accuracy and a calibration of our instruments
are traceable to the National Institute of Standards and Technology through
equipment that is calibrated at planned intervals by comparison to certified standards.
For optimal performance, EIG recommends that any meter, including those manufac-
tured by EIG, be verified for accuracy on a yearly interval using NIST traceable accu-
racy standards.
Disclaimer
The information presented in this publication has been carefully checked for
reliability; however, no responsibility is assumed for inaccuracies. The information
contained in this document is subject to change without notice.
This symbol indicates that the operator must refer must to an
important WARNING or CAUTION in the operating instructions.
Please see 4.1: Considerations When Installing Meters on page 4-
1, for important safety information regarding installation and
hookup of the Shark® 200/200T meter.
Dans ce manuel, ce symbole indique que l’opérateur doit se référer à un important
AVERTISSEMENT ou une MISE EN GARDE dans les instructions opérationnelles. Veuil-
lez consulter 4.1: Considerations When Installing Meters on page 4- 1, pour des infor-
mations importantes relatives à l’installation et branchement du compteur.
The following safety symbols may be used on the meter itself:
Les symboles de sécurité suivante peuvent être utilisés sur le compteur même:
This symbol alerts you to the presence of high voltage, which can
cause dangerous electrical shock.
Ce symbole vous indique la présence d’une haute tension qui peut
provoquer une décharge électrique dangereuse.

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Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
This symbol indicates the field wiring terminal that must be connected
to earth ground before operating the meter, which protects against
electrical shock in case of a fault condition.
Ce symbole indique que la borne de pose des canalisations in-situ qui doit être
branchée dans la mise à terre avant de faire fonctionner le compteur qui est protégé
contre une décharge électrique ou un état défectueux.
This symbol indicates that the user must refer to this manual for
specific WARNING or CAUTION information to avoid personal injury or
damage to the product.
Ce symbole indique que l'utilisateur doit se référer à ce manuel pour AVERTISSEMENT
ou MISE EN GARDE l'information pour éviter toute blessure ou tout endommagement
du produit.
About Electro Industries/GaugeTech (EIG)
Founded in 1975 by engineer and inventor Dr. Samuel Kagan, Electro Industries/
GaugeTech changed the face of power monitoring forever with its first breakthrough
innovation: an affordable, easy-to-use AC power meter.
More than forty years since its founding, Electro Industries/GaugeTech, the leader in
power monitoring and control, continues to revolutionize the industry with the highest
quality, cutting edge power monitoring and control technology on the market today.
An ISO 9001:2015 certified company, EIG sets the industry standard for advanced
power quality and reporting, revenue metering and substation data acquisition and
control. EIG products can be found on site at mainly all of today's leading manufactur-
ers, industrial giants and utilities.
EIG products are primarily designed, manufactured, tested and calibrated at our facil-
ity in Westbury, New York.

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Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
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Doc# E149701 TOC-1
Table of Contents
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Table of Contents
Customer Service and Support iii
Product Warranty iii
Statement of Calibration iv
Disclaimer iv
About Electro Industries/GaugeTech v
1:Three-Phase Power Measurement 1-1
1.1: Three-Phase System Configurations 1-1
1.1.1: Wye Connection 1-1
1.1.2: Delta Connection 1-4
1.1.3: Blondel’s Theorem and Three Phase Measurement 1-6
1.2: Power, Energy and Demand 1-8
1.3: Reactive Energy and Power Factor 1-12
1.4: Harmonic Distortion 1-14
1.5: Power Quality 1-17
2: Meter Overview and Specifications 2-1
2.1: Shark® 200 Meter Overview 2-1
2.1.1: Voltage and Current Inputs 2-5
2.1.2: Ordering Information 2-5
2.1.3: V-Switch™ Key Technology 2-8
2.1.4: Measured Values 2-10
2.1.5: Utility Peak Demand 2-11
2.2: Specifications 2-12
2.3: Compliance 2-17
2.4: Accuracy 2-19
3: Mechanical Installation 3-1
3.1: Introduction 3-1
3.2: ANSI Installation Steps 3-3
3.3: DIN Installation Steps 3-4
3.4: Transducer Installation 3-6
4: Electrical Installation 4-1
4.1: Considerations When Installing Meters 4-1
4.2: CT Leads Terminated to Meter 4-4
4.3: CT Leads Pass Through (No Meter Termination) 4-5
4.4: Quick Connect Crimp-on Terminations 4-6
4.5: Voltage and Power Supply Connections 4-7
4.6: Ground Connections 4-7
4.7: Voltage Fuses 4-7
4.8: Electrical Connection Diagrams 4-8
4.9: Extended Surge Protection for Substation Instrumentation 4-21
5: Communication Installation 5-1
5.1: Shark® 200 Meter Communication 5-1
5.1.1: IrDA Port (Com 1) 5-1
5.1.2: RS485 / KYZ Output (Com 2) 5-1
5.1.2.1: Using the Unicom 2500 5-5
5.1.2.2: Using the RS485 to USB Communication Converter 5-6

Doc# E149701 TOC-2
Table of Contents
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
5.2: Shark® 200T Transducer Communication
and Programming Overview 5-7
5.2.1: Accessing the Meter in Default Communication Mode 5-8
5.2.2: Connecting to the Meter through Communicator
EXTTM Software 5-9
5.2.2.1: Shark® 200 Meter Device Profile Settings 5-13
6: Using the Shark® 200 Meter 6-1
6.1: Introduction 6-1
6.1.1: Understanding Meter Face Elements 6-1
6.1.2: Understanding Meter Face Buttons 6-2
6.2: Using the Front Panel 6-3
6.2.1: Understanding Startup and Default Displays 6-3
6.2.2: Using the Main Menu 6-4
6.2.3: Using Reset Mode 6-5
6.2.4: Entering a Password 6-6
6.2.5: Using Configuration Mode 6-7
6.2.5.1: Configuring the Scroll Feature 6-9
6.2.5.2: Configuring CT Setting 6-10
6.2.5.3: Configuring PT Setting 6-11
6.2.5.4: Configuring Connection Setting 6-13
6.2.5.5: Configuring Communication Port Setting 6-13
6.2.6: Using Operating Mode 6-15
6.3: Understanding the % of Load Bar 6-16
6.4: Performing Watt-Hour Accuracy Testing (Verification) 6-17
7: Using the I/O Option Cards 7-1
7.1: Overview 7-1
7.2: Installing Option Cards 7-1
7.3: Configuring Option Cards 7-3
7.4: 1mA Output Card (1mAOS) 7-3
7.4.1: Specifications: 7-3
7.4.2: Default Configuration: 7-4
7.4.3: Wiring Diagram 7-5
7.5: 20mA Output Card (20mAOS) 7-6
7.5.1: Specifications 7-6
7.5.2: Default Configuration 7-7
7.5.3: Wiring Diagram 7-8
7.6: Digital Output (Relay Contact) / Digital Input Card (RO1S) 7-9
7.6.1: Specifications 7-9
7.6.2: Wiring Diagram 7-11
7.7: Pulse Output (Solid State Relay Contacts) /
Digital Input Card (P01S) 7-12
7.7.1: Specifications 7-12
7.7.2: Default Configuration 7-13
7.7.3: Wiring Diagram 7-14
7.8: Fiber Optic Communication Card (FOSTS; FOVPS) 7-15
7.8.1: Specifications 7-15
7.8.2: Wiring Diagram 7-16
7.9: 10/100BaseT Ethernet Communication Card (INP100S) 7-17
7.9.1: Specifications 7-17
7.9.2: Default Configuration 7-18
7.9.3: Wiring Diagram 7-18
7.10: IEC 61850 Protocol Ethernet Network Card (INP300S) 7-20

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Table of Contents
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
7.10.1: Specifications 7-20
7.10.2: Default Configuration 7-21
7.10.3: Wiring Diagram 7-21
8: Using the Ethernet Card (INP100S) 8-1
8.1: Overview 8-1
8.2: Hardware Connection 8-1
8.3: Performing Network Configuration 8-2
8.4: Ethernet Card Features 8-2
8.4.1: Ethernet Communication 8-3
8.4.2: Embedded Web Server 8-3
8.4.2.1: Upgrading the Ethernet Card’s Firmware 8-11
8.4.2.2: Resetting the Ethernet Card 8-13
8.4.2.3: Email Notification 8-14
8.4.2.4: Data Push 8-20
8.4.3: NTP Time Server Synchronization 8-24
8.4.4: Modbus and DNP over Ethernet 8-24
8.4.5: Keep-Alive Feature 8-24
9: Data Logging 9-1
9.1: Overview 9-1
9.2: Available Logs 9-1
A: Shark® 200 Meter Navigation Maps A-1
A.1: Introduction A-1
A.2: Navigation Maps (Sheets 1 to 4) A-1
B: Modbus Map and Retrieving Logs B-1
B.1: Introduction B-1
B.2: Modbus Register Map Sections B-1
B.3: Data Formats B-1
B.4: Floating Point Values B-2
B.5: Retrieving Logs Using the Shark® 200 Meter's Modbus Map B-3
B.5.1: Data Formats B-4
B.5.2: Shark® 200 Meter Logs B-4
B.5.3: Block Definitions B-6
B.5.4: Log Retrieval B-16
B.5.4.1: Auto-Increment B-16
B.5.4.2: Modbus Function Code 0x23 B-16
B.5.4.3: Log Retrieval Procedure B-17
B.5.4.4: Log Retrieval Example B-20
B.5.5: Log Record Interpretation B-28
B.5.6: Examples B-36
B.6: Important Note Concerning the Shark® 200 Meter's
Modbus Map B-39
B.6.1: Hex Representation B-39
B.6.2: Decimal Representation B-39
B.7: Modbus Register Map (MM-1 to MM-32) B-40
C: DNP Mapping C-1
C.1: Overview C-1
C.2: Physical Layer C-1
C.3: Data Link Layer C-1
C.4: Application Layer C-2

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Table of Contents
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
C.5: Error Reply C-3
C.6: DNP Register Map C-3
C.7: DNP Message Layouts C-6
C.8: Internal Indication Bits C-9
D: Using the USB to IrDA Adapter (CAB6490) D-1
D.1: Introduction D-1
D.2: Installation Procedures D-1
E: Using the IEC 61850 Protocol Ethernet Network Card
(INP300S) E-1
E.1: Overview of IEC 61850 E-1
E.1.1: Relationship of Clients and Servers in IEC 61850 E-2
E.1.2: Structure of IEC 61850 Network E-4
E.1.2.1: Elements of an IEC 61850 Network E-5
E.1.3: Steps in Configuring an IEC 61850 Network E-7
E.1.4: EIG’s Implementation of the IEC 61850 Server E-9
E.1.4.1: Shark® 200 Server Configuration E-11
E.1.5: Reference Materials E-12
E.1.6: Free Tools for IEC 61850 Start-up E-12
E.1.7: Commercial Tools for an IEC 61850 Implementation E-13
E.2: Using the Shark® 200 meter’s IEC 61850 Protocol Ethernet
Network Card E-13
E.2.1: Overview E-13
E.2.2: Installing the IEC 61850 Protocol Ethernet Network Card E-15
E.2.3: Configuring the IEC 61850 Protocol Ethernet Network Card E-15
E.2.3.1: Configuring the Device Profile IEC 61850 Protocol Ethernet
Network Card Settings E-15
E.2.3.2: Configuring the Meter on the IEC 61850 Network E-21
E.3: Viewing the IEC 61850 Protocol Ethernet Network Card’s
System Log E-26
E.4: Upgrading the IEC 61850 Protocol Ethernet Network Card’s
Firmware E-27
E.5: Resetting the IEC 61850 Protocol Ethernet Network Card E-28
E.6: Testing E-29
E-7: Error Codes E-30

Electro Industries/GaugeTech
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Doc# E149701 1-1
1: Three-Phase Power Measurement
1: Three-Phase Power Measurement
This introduction to three-phase power and power measurement is intended to
provide only a brief overview of the subject. The professional meter engineer or meter
technician should refer to more advanced documents such as the EEI Handbook for
Electricity Metering and the application standards for more in-depth and technical
coverage of the subject.
1.1: Three-Phase System Configurations
Three-phase power is most commonly used in situations where large amounts of
power will be used because it is a more effective way to transmit the power and
because it provides a smoother delivery of power to the end load. There are two
commonly used connections for three-phase power, a wye connection or a delta
connection. Each connection has several different manifestations in actual use.
When attempting to determine the type of connection in use, it is a good practice to
follow the circuit back to the transformer that is serving the circuit. It is often not
possible to conclusively determine the correct circuit connection simply by counting
the wires in the service or checking voltages. Checking the transformer connection
will provide conclusive evidence of the circuit connection and the relationships
between the phase voltages and ground.
1.1.1: Wye Connection
The wye connection is so called because when you look at the phase relationships and
the winding relationships between the phases it looks like a Y. Figure 1.1 depicts the
winding relationships for a wye-connected service. In a wye service the neutral (or
center point of the wye) is typically grounded. This leads to common voltages of 208/
120 and 480/277 (where the first number represents the phase-to-phase voltage and
the second number represents the phase-to-ground voltage).

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Doc# E149701 1-2
1: Three-Phase Power Measurement
Figure 1.1: Three-phase Wye Winding
The three voltages are separated by 120oelectrically. Under balanced load conditions
the currents are also separated by 120o. However, unbalanced loads and other
conditions can cause the currents to depart from the ideal 120oseparation. Three-
phase voltages and currents are usually represented with a phasor diagram. A phasor
diagram for the typical connected voltages and currents is shown in Figure 1.2.
Figure 1.2: Phasor Diagram Showing Three-phase Voltages and Currents
N
Phase 1
Phase 3
Phase 2
V
C
V
A
V
B
V
A
V
B
V
C
N
I
B
I
A
I
C

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Doc# E149701 1-3
1: Three-Phase Power Measurement
The phasor diagram shows the 120oangular separation between the phase voltages.
The phase-to-phase voltage in a balanced three-phase wye system is 1.732 times the
phase-to-neutral voltage. The center point of the wye is tied together and is typically
grounded. Table 1.1 shows the common voltages used in the United States for wye-
connected systems.
Usually a wye-connected service will have four wires: three wires for the phases and
one for the neutral. The three-phase wires connect to the three phases (as shown in
Figure 1.1). The neutral wire is typically tied to the ground or center point of the wye.
In many industrial applications the facility will be fed with a four-wire wye service but
only three wires will be run to individual loads. The load is then often referred to as a
delta-connected load but the service to the facility is still a wye service; it contains
four wires if you trace the circuit back to its source (usually a transformer). In this
type of connection the phase to ground voltage will be the phase-to-ground voltage
indicated in Table 1, even though a neutral or ground wire is not physically present at
the load. The transformer is the best place to determine the circuit connection type
because this is a location where the voltage reference to ground can be conclusively
identified.
Phase to Ground Voltage Phase to Phase Voltage
120 volts 208 volts
277 volts 480 volts
2,400 volts 4,160 volts
7,200 volts 12,470 volts
7,620 volts 13,200 volts
Table 1: Common Phase Voltages on Wye Services

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Doc# E149701 1-4
1: Three-Phase Power Measurement
1.1.2: Delta Connection
Delta-connected services may be fed with either three wires or four wires. In a three-
phase delta service the load windings are connected from phase-to-phase rather than
from phase-to-ground. Figure 1.3 shows the physical load connections for a delta
service.
Figure 1.3: Three-phase Delta Winding Relationship
In this example of a delta service, three wires will transmit the power to the load. In a
true delta service, the phase-to-ground voltage will usually not be balanced because
the ground is not at the center of the delta.
Figure 1.4 shows the phasor relationships between voltage and current on a three-
phase delta circuit.
In many delta services, one corner of the delta is grounded. This means the phase to
ground voltage will be zero for one phase and will be full phase-to-phase voltage for
the other two phases. This is done for protective purposes.
V
C
Phase 1
Phase 3
Phase 2
V
A
V
B

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Doc# E149701 1-5
1: Three-Phase Power Measurement
Figure 1.4: Phasor Diagram, Three-Phase Voltages and Currents, Delta-Connected
Another common delta connection is the four-wire, grounded delta used for lighting
loads. In this connection the center point of one winding is grounded. On a 120/240
volt, four-wire, grounded delta service the phase-to-ground voltage would be 120
volts on two phases and 208 volts on the third phase. Figure 1.5 shows the phasor
diagram for the voltages in a three-phase, four-wire delta system.
Figure 1.5: Phasor Diagram Showing Three-phase Four-Wire Delta-Connected System

I
A
V
CA
V
AB
V
BC
I
C
I
B
V
A
V
C
V
B
V
CA
V
AB
N V
BC

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Doc# E149701 1-6
1: Three-Phase Power Measurement
1.1.3: Blondel’s Theorem and Three Phase Measurement
In 1893 an engineer and mathematician named Andre E. Blondel set forth the first
scientific basis for polyphase metering. His theorem states:
If energy is supplied to any system of conductors through N wires, the total power in
the system is given by the algebraic sum of the readings of N wattmeters so arranged
that each of the N wires contains one current coil, the corresponding potential coil
being connected between that wire and some common point. If this common point is
on one of the N wires, the measurement may be made by the use of N-1 Wattmeters.
The theorem may be stated more simply, in modern language:
In a system of N conductors, N-1 meter elements will measure the power or energy
taken provided that all the potential coils have a common tie to the conductor in
which there is no current coil.
Three-phase power measurement is accomplished by measuring the three individual
phases and adding them together to obtain the total three phase value. In older ana-
log meters, this measurement was accomplished using up to three separate elements.
Each element combined the single-phase voltage and current to produce a torque on
the meter disk. All three elements were arranged around the disk so that the disk was
subjected to the combined torque of the three elements. As a result the disk would
turn at a higher speed and register power supplied by each of the three wires.
According to Blondel's Theorem, it was possible to reduce the number of elements
under certain conditions. For example, a three-phase, three-wire delta system could
be correctly measured with two elements (two potential coils and two current coils) if
the potential coils were connected between the three phases with one phase in com-
mon.
In a three-phase, four-wire wye system it is necessary to use three elements. Three
voltage coils are connected between the three phases and the common neutral con-
ductor. A current coil is required in each of the three phases.
In modern digital meters, Blondel's Theorem is still applied to obtain proper metering.
The difference in modern meters is that the digital meter measures each phase volt-
age and current and calculates the single-phase power for each phase. The meter
then sums the three phase powers to a single three-phase reading.

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Doc# E149701 1-7
1: Three-Phase Power Measurement
Some digital meters measure the individual phase power values one phase at a time.
This means the meter samples the voltage and current on one phase and calculates a
power value. Then it samples the second phase and calculates the power for the sec-
ond phase. Finally, it samples the third phase and calculates that phase power. After
sampling all three phases, the meter adds the three readings to create the equivalent
three-phase power value. Using mathematical averaging techniques, this method can
derive a quite accurate measurement of three-phase power.
More advanced meters actually sample all three phases of voltage and current
simultaneously and calculate the individual phase and three-phase power values. The
advantage of simultaneous sampling is the reduction of error introduced due to the
difference in time when the samples were taken.
Figure 1.6: Three-Phase Wye Load Illustrating Kirchhoff’s Law and Blondel’s Theorem
Blondel's Theorem is a derivation that results from Kirchhoff's Law. Kirchhoff's Law
states that the sum of the currents into a node is zero. Another way of stating the
same thing is that the current into a node (connection point) must equal the current
out of the node. The law can be applied to measuring three-phase loads. Figure 1.6
shows a typical connection of a three-phase load applied to a three-phase, four-wire
service. Kirchhoff's Law holds that the sum of currents A, B, C and N must equal zero
or that the sum of currents into Node "n" must equal zero.
If we measure the currents in wires A, B and C, we then know the current in wire N by
Kirchhoff's Law and it is not necessary to measure it. This fact leads us to the
conclusion of Blondel's Theorem- that we only need to measure the power in three of
Phase B
Phase C
Phase A
A
B
C
N
Node "n"

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Doc# E149701 1-8
1: Three-Phase Power Measurement
the four wires if they are connected by a common node. In the circuit of Figure 1.6 we
must measure the power flow in three wires. This will require three voltage coils and
three current coils (a three-element meter). Similar figures and conclusions could be
reached for other circuit configurations involving Delta-connected loads.
1.2: Power, Energy and Demand
It is quite common to exchange power, energy and demand without differentiating
between the three. Because this practice can lead to confusion, the differences
between these three measurements will be discussed.
Power is an instantaneous reading. The power reading provided by a meter is the
present flow of watts. Power is measured immediately just like current. In many
digital meters, the power value is actually measured and calculated over a one second
interval because it takes some amount of time to calculate the RMS values of voltage
and current. But this time interval is kept small to preserve the instantaneous nature
of power.
Energy is always based on some time increment; it is the integration of power over a
defined time increment. Energy is an important value because almost all electric bills
are based, in part, on the amount of energy used.
Typically, electrical energy is measured in units of kilowatt-hours (kWh). A kilowatt-
hour represents a constant load of one thousand watts (one kilowatt) for one hour.
Stated another way, if the power delivered (instantaneous watts) is measured as
1,000 watts and the load was served for a one hour time interval then the load would
have absorbed one kilowatt-hour of energy. A different load may have a constant
power requirement of 4,000 watts. If the load were served for one hour it would
absorb four kWh. If the load were served for 15 minutes it would absorb ¼ of that
total or one kWh.
Figure 1.7 shows a graph of power and the resulting energy that would be transmitted
as a result of the illustrated power values. For this illustration, it is assumed that the
power level is held constant for each minute when a measurement is taken. Each bar
in the graph will represent the power load for the one-minute increment of time. In
real life the power value moves almost constantly.
The data from Figure 1.7 is reproduced in Table 2 to illustrate the calculation of
energy. Since the time increment of the measurement is one minute and since we