This presentation covers the differences between self contained and transformer or instrument rated meter sites, transformer rated meter forms, test switches and CT's, Blondel's Theorem and why it matters to metering, meter accuracy testing in the field, checking the health of your CT's and PT's, and site verification (not just meter testing).
This presentation will cover the basics and differences between self-contained and transformer or instrument rated meter sites. Also discussed are transformer rated meter forms, test switches and CT's, Blondel's Theorem and why this matters to metering, meter accuracy testing in the field, checking the health of your CT's and PT's, and Site Verification (and not just meter testing).
In this presentation, the topics covered include: differences between self contained and transformer or instrument rated meter sites; transformer rated meter forms; test switches and CT's; Blondel's Theorem and why this matters to us in metering; meter accuracy testing in the field; checking the health of your CT's and PT's; and site verification. This presentation was given at the Mississippi Electric Meter School on October 10, 2018.
This presentation covers the basics of self-contained and transformer rated meter sites, transformer rated meter forms, test switches and CTs, Blondel's Theorom, meter accuracy testing in the field, and site verification. This presentation was given during the PREA Meter School in March 2019.
In this presentation, the topics covered include: differences between self contained and transformer or instrument rated meter sites; transformer rated meter forms; test switches and CT's; Blondel's Theorem and why this matters to us in metering; meter accuracy testing in the field; checking the health of your CT's and PT's; and site verification.
Learn the differences between self-contained and transformer or instrument rated meter sites, test switches and CTs, Blondel's Theorem, meter accuracy testing, site verification, and more! 01/29/2019
This presentation will cover the basics and differences between self-contained and transformer or instrument rated meter sites. Also discussed are transformer rated meter forms, test switches and CT's, Blondel's Theorem and why this matters to metering, meter accuracy testing in the field, checking the health of your CT's and PT's, and Site Verification (and not just meter testing).
This presentation covers differences between self-contained and instrument or transformer rated sites; transformer rated meter forms; test switches and CTs; Blondel's Theorem; meter accuracy testing; checking the health of your CTs and PTs; and site verification (and not just meter testing). This presentation was given at the PREA Meter School. 03/10/20.
This presentation will cover the basics and differences between self-contained and transformer or instrument rated meter sites. Also discussed are transformer rated meter forms, test switches and CT's, Blondel's Theorem and why this matters to metering, meter accuracy testing in the field, checking the health of your CT's and PT's, and Site Verification (and not just meter testing).
In this presentation, the topics covered include: differences between self contained and transformer or instrument rated meter sites; transformer rated meter forms; test switches and CT's; Blondel's Theorem and why this matters to us in metering; meter accuracy testing in the field; checking the health of your CT's and PT's; and site verification. This presentation was given at the Mississippi Electric Meter School on October 10, 2018.
This presentation covers the basics of self-contained and transformer rated meter sites, transformer rated meter forms, test switches and CTs, Blondel's Theorom, meter accuracy testing in the field, and site verification. This presentation was given during the PREA Meter School in March 2019.
In this presentation, the topics covered include: differences between self contained and transformer or instrument rated meter sites; transformer rated meter forms; test switches and CT's; Blondel's Theorem and why this matters to us in metering; meter accuracy testing in the field; checking the health of your CT's and PT's; and site verification.
Learn the differences between self-contained and transformer or instrument rated meter sites, test switches and CTs, Blondel's Theorem, meter accuracy testing, site verification, and more! 01/29/2019
This presentation will cover the basics and differences between self-contained and transformer or instrument rated meter sites. Also discussed are transformer rated meter forms, test switches and CT's, Blondel's Theorem and why this matters to metering, meter accuracy testing in the field, checking the health of your CT's and PT's, and Site Verification (and not just meter testing).
This presentation covers differences between self-contained and instrument or transformer rated sites; transformer rated meter forms; test switches and CTs; Blondel's Theorem; meter accuracy testing; checking the health of your CTs and PTs; and site verification (and not just meter testing). This presentation was given at the PREA Meter School. 03/10/20.
Learn the differences between self-contained and transformer or instrument rated meter sites, test switches and CTs, Blondel’s Theorem, meter accuracy testing, site verification, and more! This presentation was given at MEUA Meter School. 03.03.20
This document provides an overview and agenda for an advanced training session on field CT testing. It discusses the key topics of ratio, burden, and admittance testing to evaluate the functionality and health of current transformers (CTs). The summary discusses:
- Ratio testing measures the proportional relationship between primary and secondary currents.
- Burden testing checks that CTs maintain accurate ratios with varying levels of burden on the secondary loop, up to specified limits.
- Admittance testing uses injected audio signals to evaluate the overall "health" of the CT's secondary loop in millisiemens values. Interpreting the results requires analysis to understand implications.
- Demagnetization procedures are also covered to address issues like
This document discusses transformer-rated metering fundamentals, including:
- Transformer-rated meters measure current through current transformers and sometimes voltage transformers, unlike self-contained meters which connect directly to the load.
- Blondel's theorem states that total power in a polyphase system can be measured using N-1 meters connected between each line and a common point.
- Meeting Blondel's theorem ensures accurate power measurements under all conditions, while violations may cause errors if voltage and current are not balanced.
- Examples show how to apply Blondel's theorem correctly for 3-phase 4-wire systems.
Learning meter forms is as easy as 1S-2S-3S! You’ll learn the most common metering forms and how they are used. This presentation also dives into Blondel’s Theorem and how it is used to determine what type of meter to install at different services.
This presentation goes over the varying types of meter forms, self-contained vs. transformer-rated, as well as Blondel's Theorem. This presentation was given at the PREA Meter School.
This document provides an overview of test switches used for transformer-rated metering services. It discusses typical self-contained and transformer-rated metering services. It then covers test switch operation, specifications from ANSI C12.9, configurations, accessories like test plugs, and considerations for sites without existing test switches. The purpose is to familiarize attendees with using and specifying test switches and their components for safe testing of current transformers. It concludes with an optional multiple choice quiz.
John Kretzschmar presented on advanced polyphase metering on June 20, 2017. The presentation covered the evolution of meters and loads over time, from the past to present and possibilities for the future. It also discussed changes in communications and how non-linear loads have impacted the basic computations of metering. The bulk of the presentation was focused on providing an overview of three-phase power concepts including phasors, voltage and current relationships, and different connection types for three-phase systems.
This presentation discusses the differences between self-contained and transformer or instrument rated meter sites; transformer rated meter forms; test switches and CTs; meter accuracy testing in the field; checking the health of your CTs and PTs; and Site Verification. This presentation was given at the MEUA Meter School. 03/03/20
Current transformers (CTs) are tested for correct ratio and functionality at rated burdens. Ratio testing involves measuring the primary and secondary currents to calculate the ratio. Burden testing applies varying levels of burden to the secondary loop to ensure the CT maintains accuracy within 0.3% up to 0.5 ohms of burden, as specified by ANSI standards. Admittance testing uses an audio frequency signal to measure the "health" of the secondary loop. CTs can become magnetized over time and may need to be demagnetized by slowly increasing and decreasing the secondary resistance to saturate and remove residual magnetism.
Then … Now … and Tomorrow. This presentation discusses how meters, loads, and communications have changed over the years and why it is important today. Standards Changes are reviewed as well as new definitions.
This document provides an introduction to self-contained meter testing. It discusses why utilities test meters, the different types of meter tests, how test plans work, and some basic electrical theory behind meter testing. The key points covered are: utilities regulate meter testing for accuracy; the main types of meter tests are for new, returned, and in-service meters; statistical and periodic test plans exist; and basic electrical laws like Ohm's law and Kirchoff's laws are important for understanding meter functionality.
This presentation was given at the PREA Meter School and gives an introduction to transformer rated metering including meter forms, test switches, CTs, Blondel's Theorem, site verification and more. 03/10/20
This document discusses voltage, current, resistance and power measurements using analog instruments. It describes the operating principles of moving coil meters for measuring DC current and voltage. A moving coil meter consists of a coil suspended in a magnetic field that deflects proportional to the current or voltage. Higher current and voltage ranges are achieved using shunt and multiplier resistors. The document also covers resistance measurement using an ohmmeter, and compares analog and digital instruments.
Electronics measurements and instrumentation basicsAbhishek Thakkar
This document discusses electronic measurements and instruments. It covers units and standards used in measurement, as well as concepts like accuracy, precision, resolution, and error. It also describes common electrical and non-electrical units, temperature scales, and metric prefixes used in engineering notation. The document outlines measurement standards and statistical analysis techniques used to characterize measurements. Finally, it provides a basic overview of the components in an electronic measurement system, including transducers, signal conditioners, analog-to-digital converters, signal processors, and display units.
This lab aimed to design basic DC meters to measure current and voltage. For the ammeter, the resistance of the meter movement was found to be 344.68 Ω. Using this value, a shunt resistor of 14.37 Ω was calculated. Testing showed the designed ammeter had an average error of 1.815% compared to a multimeter. A voltmeter was also designed using a meter movement and 49,655 kΩ resistor, which tested with an average 6.06% error. Finally, voltage dividers were analyzed theoretically and with the designed voltmeter, showing close agreement.
The best way to be sure you are getting the correct revenue from a site is to test the entire site. Learn how to find any diversions, corrosion, broken or frayed wiring as well as all the tests you can perform while at a site.
In this presentation, you will learn the basics - differences between self contained and transformer or instrument rated meter sites, transformer rated meter forms, test switches and CT's, meter accuracy testing in the field, checking the health of your CT's and PT's, and site verification
Learn the differences between self-contained and transformer or instrument rated meter sites, test switches and CTs, Blondel’s Theorem, meter accuracy testing, site verification, and more! This presentation was given at MEUA Meter School. 03.03.20
This document provides an overview and agenda for an advanced training session on field CT testing. It discusses the key topics of ratio, burden, and admittance testing to evaluate the functionality and health of current transformers (CTs). The summary discusses:
- Ratio testing measures the proportional relationship between primary and secondary currents.
- Burden testing checks that CTs maintain accurate ratios with varying levels of burden on the secondary loop, up to specified limits.
- Admittance testing uses injected audio signals to evaluate the overall "health" of the CT's secondary loop in millisiemens values. Interpreting the results requires analysis to understand implications.
- Demagnetization procedures are also covered to address issues like
This document discusses transformer-rated metering fundamentals, including:
- Transformer-rated meters measure current through current transformers and sometimes voltage transformers, unlike self-contained meters which connect directly to the load.
- Blondel's theorem states that total power in a polyphase system can be measured using N-1 meters connected between each line and a common point.
- Meeting Blondel's theorem ensures accurate power measurements under all conditions, while violations may cause errors if voltage and current are not balanced.
- Examples show how to apply Blondel's theorem correctly for 3-phase 4-wire systems.
Learning meter forms is as easy as 1S-2S-3S! You’ll learn the most common metering forms and how they are used. This presentation also dives into Blondel’s Theorem and how it is used to determine what type of meter to install at different services.
This presentation goes over the varying types of meter forms, self-contained vs. transformer-rated, as well as Blondel's Theorem. This presentation was given at the PREA Meter School.
This document provides an overview of test switches used for transformer-rated metering services. It discusses typical self-contained and transformer-rated metering services. It then covers test switch operation, specifications from ANSI C12.9, configurations, accessories like test plugs, and considerations for sites without existing test switches. The purpose is to familiarize attendees with using and specifying test switches and their components for safe testing of current transformers. It concludes with an optional multiple choice quiz.
John Kretzschmar presented on advanced polyphase metering on June 20, 2017. The presentation covered the evolution of meters and loads over time, from the past to present and possibilities for the future. It also discussed changes in communications and how non-linear loads have impacted the basic computations of metering. The bulk of the presentation was focused on providing an overview of three-phase power concepts including phasors, voltage and current relationships, and different connection types for three-phase systems.
This presentation discusses the differences between self-contained and transformer or instrument rated meter sites; transformer rated meter forms; test switches and CTs; meter accuracy testing in the field; checking the health of your CTs and PTs; and Site Verification. This presentation was given at the MEUA Meter School. 03/03/20
Current transformers (CTs) are tested for correct ratio and functionality at rated burdens. Ratio testing involves measuring the primary and secondary currents to calculate the ratio. Burden testing applies varying levels of burden to the secondary loop to ensure the CT maintains accuracy within 0.3% up to 0.5 ohms of burden, as specified by ANSI standards. Admittance testing uses an audio frequency signal to measure the "health" of the secondary loop. CTs can become magnetized over time and may need to be demagnetized by slowly increasing and decreasing the secondary resistance to saturate and remove residual magnetism.
Then … Now … and Tomorrow. This presentation discusses how meters, loads, and communications have changed over the years and why it is important today. Standards Changes are reviewed as well as new definitions.
This document provides an introduction to self-contained meter testing. It discusses why utilities test meters, the different types of meter tests, how test plans work, and some basic electrical theory behind meter testing. The key points covered are: utilities regulate meter testing for accuracy; the main types of meter tests are for new, returned, and in-service meters; statistical and periodic test plans exist; and basic electrical laws like Ohm's law and Kirchoff's laws are important for understanding meter functionality.
This presentation was given at the PREA Meter School and gives an introduction to transformer rated metering including meter forms, test switches, CTs, Blondel's Theorem, site verification and more. 03/10/20
This document discusses voltage, current, resistance and power measurements using analog instruments. It describes the operating principles of moving coil meters for measuring DC current and voltage. A moving coil meter consists of a coil suspended in a magnetic field that deflects proportional to the current or voltage. Higher current and voltage ranges are achieved using shunt and multiplier resistors. The document also covers resistance measurement using an ohmmeter, and compares analog and digital instruments.
Electronics measurements and instrumentation basicsAbhishek Thakkar
This document discusses electronic measurements and instruments. It covers units and standards used in measurement, as well as concepts like accuracy, precision, resolution, and error. It also describes common electrical and non-electrical units, temperature scales, and metric prefixes used in engineering notation. The document outlines measurement standards and statistical analysis techniques used to characterize measurements. Finally, it provides a basic overview of the components in an electronic measurement system, including transducers, signal conditioners, analog-to-digital converters, signal processors, and display units.
This lab aimed to design basic DC meters to measure current and voltage. For the ammeter, the resistance of the meter movement was found to be 344.68 Ω. Using this value, a shunt resistor of 14.37 Ω was calculated. Testing showed the designed ammeter had an average error of 1.815% compared to a multimeter. A voltmeter was also designed using a meter movement and 49,655 kΩ resistor, which tested with an average 6.06% error. Finally, voltage dividers were analyzed theoretically and with the designed voltmeter, showing close agreement.
The best way to be sure you are getting the correct revenue from a site is to test the entire site. Learn how to find any diversions, corrosion, broken or frayed wiring as well as all the tests you can perform while at a site.
In this presentation, you will learn the basics - differences between self contained and transformer or instrument rated meter sites, transformer rated meter forms, test switches and CT's, meter accuracy testing in the field, checking the health of your CT's and PT's, and site verification
The best way to be sure you are getting the correct revenue from a site is to test the entire site. Learn how to find any diversions, corrosion, broken or frayed wiring as well as all the tests you can perform while at a site.
This presentation goes over CT functionality basics, ratio testing, burden testing, admittance testing, and demag functions. Presented at NC Meter School 2022.
This presentation was for an Advanced Session at North Carolina Meter School and discussed CT functionality Basics, Terminology and Specifications, Ratio Testing, Burden Testing, Admittance Testing, and Demag Functions.
This document discusses best practices for meter and instrument transformer testing in an Advanced Metering Infrastructure (AMI) system. It addresses the need to test meters and transformers for accuracy upon installation, return to service, and periodically while in service. Site verification testing is also recommended to check for wiring errors and ensure meters and transformers are properly sized. The document emphasizes that transformer-rated services, which represent a small portion of customers but a large portion of revenue, should be a priority for meter testing resources given their financial impact. AMI data can help identify transformer-rated services for further evaluation and testing.
The document summarizes key components and operating principles of switchgear, including circuit breakers, current transformers, and voltage transformers. It describes:
- Circuit breakers consist of contacts, operating mechanisms, trip and close coils, and auxiliary switches. They are rated by voltage and breaking capacity.
- Current transformers reduce high currents to safely measurable levels for meters and relays. They are rated by voltage, current ratios, and accuracy class.
- Voltage transformers reduce high voltages to safely measurable levels. They are rated by voltage, turns ratio, and accuracy class.
This presentation was given during the 2023 Southeastern Meter School in Auburn, AL. Understand the need and best practices for instrument transformer testing in an AMI world, including why and how to test, and what range of tests and checks to perform in the shop and in the field.
This document discusses best practices for instrument transformer testing. It recommends performing shop tests on every meter, current transformer (CT), and voltage transformer (VT) going into a transformer rated service to check accuracy and functionality. Field technicians should perform an initial site verification at every transformer rated service to establish a baseline and then re-check problematic sites identified through AMI analytics, focusing on issues like reversed polarity, missing load on a phase, or performance outside rating ranges. Reducing resources spent testing self-contained meters allows leveraging AMI data to replace older processes and focus on transformer rated services where revenue is highest.
The document discusses instrument transformer testing in shops and fields. It emphasizes the importance of testing transformer-rated services, where revenue is highest. Key points include: testing all CTs and VTs in shops, including ratio and accuracy checks; performing baseline site verifications of all transformer-rated services; and using AMI data to identify field issues like no draw on legs or reversed polarity for re-testing. The goal is reducing time on self-contained metering to focus limited resources on transformer-rated sites where testing and verification provide the highest payback.
This presentation was given with LUCELEC at the CARILEC CEO & Leadership Conference and covers system loss and what to do to reduce it; why transformer rated metering is important; site verification and not just meter testing; and management systems and utilizing AMI data to control and reduce billing errors.
Why test on site? The utility wants to receive full payment for the services it provides. The customer wants to be billed fairly to get the lowest bill possible. This set of infographics is to facilitate the understanding of the need to test electricity meters and practically show how testing should be done. Intended for technicians, engineers, students, utilities staff and all interested in reliable energy measurement. Many definitions and examples are simplified to get clear way of reliable test results obtaining. Although the author tried to avoid errors, they can probably be found in the content, hence any comments are welcomed.
Why test on site? The utility wants to receive full payment for the services it provides. The customer wants to be billed fairly to get the lowest bill possible. This set of infographics is to facilitate the understanding of the need to test electricity meters and practically show how testing should be done. Intended for technicians, engineers, students, utilities staff and all interested in reliable energy measurement. Many definitions and examples are simplified to get clear way of reliable test results obtaining. Although the author tried to avoid errors, they can probably be found in the content, hence any comments are welcomed.
The document summarizes key components and operating principles of switchgear, including circuit breakers, current transformers, and voltage transformers. It provides specifications for each component and describes their functions. Troubleshooting tips are also included, outlining common issues with circuit breakers not closing or opening and potential remedies.
To subject Electric Meters to non-nominal conditions more similar to what meters would experience in the field as opposed to the nominal operating conditions typically used when testing meter accuracy in a shop environment.
Unit I - Basic Electrical and Electronics Engineeringarunatshare
This document provides an overview of basic electrical and electronics engineering concepts including circuit components and Ohm's law. It discusses electric current, voltage, power, energy, sources, and basic circuit elements like resistors, inductors, and capacitors. Kirchhoff's laws and different circuit analysis methods like mesh current, node voltage, and source transformation are also introduced. Finally, the document covers electrical measurement techniques and types of instruments.
Basics Of Energy Matering And Fraud DetectionAbhisek Swain
This document discusses basics of energy metering and fraud detection. It covers types of single-phase and three-phase energy meters, testing of meters in laboratories and at field sites, and different types of tampering in energy meters. The contents include basics of power measurement in AC circuits, types of single-phase meters like induction and electronic meters, testing routines for single-phase meters in the lab, field testing of single-phase meters, types of three-phase meters, field and lab testing of three-phase meters, common tampering methods like potential link open and current bypass, and references.
This document provides information about substations and maintenance. It discusses indoor and outdoor substations, the various units within a substation, testing methods for circuit breakers, CTs, and PTs, as well as maintenance procedures. Neutral earthing and different neutral earthing methods like solid grounding, resistance grounding, and reactance grounding are also covered.
Similar to Transformer Rated Metering Site Verification (20)
Low power architecture of logic gates using adiabatic techniquesnooriasukmaningtyas
The growing significance of portable systems to limit power consumption in ultra-large-scale-integration chips of very high density, has recently led to rapid and inventive progresses in low-power design. The most effective technique is adiabatic logic circuit design in energy-efficient hardware. This paper presents two adiabatic approaches for the design of low power circuits, modified positive feedback adiabatic logic (modified PFAL) and the other is direct current diode based positive feedback adiabatic logic (DC-DB PFAL). Logic gates are the preliminary components in any digital circuit design. By improving the performance of basic gates, one can improvise the whole system performance. In this paper proposed circuit design of the low power architecture of OR/NOR, AND/NAND, and XOR/XNOR gates are presented using the said approaches and their results are analyzed for powerdissipation, delay, power-delay-product and rise time and compared with the other adiabatic techniques along with the conventional complementary metal oxide semiconductor (CMOS) designs reported in the literature. It has been found that the designs with DC-DB PFAL technique outperform with the percentage improvement of 65% for NOR gate and 7% for NAND gate and 34% for XNOR gate over the modified PFAL techniques at 10 MHz respectively.
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...University of Maribor
Slides from talk presenting:
Aleš Zamuda: Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapter and Networking.
Presentation at IcETRAN 2024 session:
"Inter-Society Networking Panel GRSS/MTT-S/CIS
Panel Session: Promoting Connection and Cooperation"
IEEE Slovenia GRSS
IEEE Serbia and Montenegro MTT-S
IEEE Slovenia CIS
11TH INTERNATIONAL CONFERENCE ON ELECTRICAL, ELECTRONIC AND COMPUTING ENGINEERING
3-6 June 2024, Niš, Serbia
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
1. Slide 1
10/02/2012 Slide 1
Transformer Rated
Metering Site
Verification
Prepared by Tom Lawton,TESCO
For Pennsylvania
Tuesday, November 7, 2017
10:15 a.m.
2. Slide 2
Topics we will be covering
• The Basics- Differences Between Self
Contained and Transformer or Instrument
Rated Meter Sites
• Transformer Rated Meter Forms
• Test Switches and CT’s
• Blondel’s Theorem and why this matters to
us in metering
• Meter Accuracy Testing in the Field
• Checking the Health of your CT’s and PT’s
• Site Verification and not just meter testing
3. Slide 3
Self Contained Metering
•Typically found in residential
metering
•Meters are capable of handling
the direct incoming amperage
•Meter is connected directly to
the load being measured
•Meter is part of the circuit
•When the meter is removed
from the socket, power to the
customer is interrupted
4. Slide 4
Transformer Rated Metering
• Meter measures scaled down
representation of the load.
• Scaling is accomplished by the use
of external current transformers
(CTs) and sometimes voltage
transformers or PTs).
• The meter is NOT part of the circuit
• When the meter is removed from
the socket, power to the customer
is not effected.
5. Slide 5
9S Meter Installation with 400:5 CT’s
400A
400A
400A
LOAD
5A 5A 5A
SOURCE
PHASE A
PHASE B
PHASE C
The Basic Components
7. Slide 7
TESCO/Georgia Power 2017 Caribbean Meter School
Fundamentals of Polyphase Field Meter Testing and Site Verification
Full Load
Light Load
Power Factor
Meter Accuracy Testing
Meter Accuracy
Testing in a Nutshell
8. Slide 8
The Importance of CT Testing in the Field
• One transformer in three wired
backwards will give the customer a
bill of 1/3rd
the actual bill.
• One broken wire to a single
transformer will give the customer a
bill of 2/3rd
the actual bill
• One dual ratio transformer
inappropriately marked in the billing
system as 400:5 instead of 800:5
provides a bill that is ½ of the actual
bill. And the inverse will give a bill
double of what should have been
sent. Both are lose-lose situations
for the utility.
9. Slide 9
The Importance of CT Testing in the Field
(cont)
•Cross Phasing (wiring errors)
•Loose or Corroded Connections
•CT Mounted Backwards
•CT’s with Shorted Turns
•Wrong Selection of Dual Ratio CT
•Detect Magnetized CT’s
•Burden Failure in Secondary Circuit
•Open or Shorted Secondary
•Mislabeled CT’s
•Ensures all Shorting Blocks have been Removed
11. Slide 11
Fundamentals of Polyphase Field Meter
Testing and Site Verification
Functionality with Burden Present on the Secondary Loop
PHASE A
• Some burden will always be
present – junctions, meter
coils, test switches, cables,
etc.
• CT’s must be able to
maintain an accurate ratio
with burden on the
secondary.
12. Slide 12
Fundamentals of Polyphase Field Meter
Testing and Site Verification
Functionality with Burden Present on the Secondary Loop
Example Burden Spec:
0.3% @ B0.1, B0.2, B0.5
or
There should be less than the 0.3%
change in secondary current from initial
(“0” burden) reading, when up to 0.5 Ohms
of burden is applied
Fundamentals of Polyphase Field Meter
Testing and Site Verification
13. Slide 13
Fundamentals of Polyphase Field Meter
Testing and Site Verification
Current Transformers Conceptual
Rtepresentation
Real, with core losses
Ideal. No losses
14. Slide 14
Fundamentals of Polyphase Field Meter
Testing and Site Verification
Functionality with Burden Present on the Secondary Loop
0.3% @ B0.1, B0.2, B0.5
0.0000
1.0000
2.0000
3.0000
4.0000
5.0000
6.0000
0 2 4 6 8
Initial Reading = 5Amps
0.3% x 5A = 0.015A
5A – 0.015 = 4.985A
Burden Reading
0 5.0000
0.1 4.9999
0.2 4.9950
0.5 4.9900
1 4.9800
2 4.9500
4 4.0000
8 0.8000
15. Slide 15
Ratio of Primary Current to Secondary Current
PHASE A
SOURCE LOAD
400A
400A
400A
5A5A
Calculate Ratio
Fundamentals of Polyphase Field Meter
Testing and Site Verification
16. Slide 16
Three Phase Power
Blondel’s Theorem
The theory of polyphase watthour metering was first set forth on a scientific
basis in 1893 by Andre E. Blondel, engineer and mathematician. His theorem
applies to the measurement of real power in a polyphase system of any number
of wires. The theorem is as follows:
- 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 voltage 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.
17. Slide 17
Three Phase Power
Blondel’s Theorem
• Simply – We can measure the power in a
N wire system by measuring the power in
N-1 conductors.
• For example, in a 4-wire, 3-phase system
we need to measure the power in 3
circuits.
18. Slide 18
Three Phase Power
Blondel’s Theorem
• If a meter installation meets Blondel’s
Theorem then we will get accurate power
measurements under all circumstances.
• If a metering system does not meet
Blondel’s Theorem then we will only get
accurate measurements if certain
assumptions are met.
19. Slide 19
Blondel’s Theorem
• Three wires
• Two voltage measurements with
one side common to Line 2
• Current measurements on lines
1 & 3.
This satisfies Blondel’s
Theorem.
20. Slide 20
Blondel’s Theorem
• Four wires
• Two voltage measurements to
neutral
• Current measurements on lines 1 &
3. How about line 2?
This DOES NOT satisfy Blondel’s
Theorem.
21. Slide 21
Blondel’s Theorem
• In the previous example:
– What are the “ASSUMPTIONS”?
– When do we get errors?
• What would the “Right Answer” be?
• What did we measure?
)cos()cos()cos( cccbbbaaasys IVIVIVP θθθ ++=
)]cos()cos([)]cos()cos([ bbcccbbaaasys IIVIIVP θθθθ −+−=
22. Slide 22
Blondel’s Theorem
• Phase B power would be:
– P = Vb Ib cosθ
• But we aren’t measuring Vb
• What we are measuring is:
– IbVacos(60- θ) + IbVccos(60+ θ)
• cos(α + β) = cos(α)cos(β) - sin(α)sin(β)
• cos(α - β) = cos(α)cos(β) + sin(α)sin(β)
• So
24. Slide 24
Blondel’s Theorem
• If Va ≠ Vb ≠ Vc then the error is
• %Error =
-Ib{(Va+Vc)/(2Vb) - (Va-Vc) 0.866sin(θ)/(Vbcos(θ))
How big is this in reality? If
Va=117, Vb=120, Vc=119, PF=1 then E=-1.67%
Va=117, Vb=116, Vc=119, PF=.866 then E=-1.67%
26. Slide 26
Site Verification: Why should we invest our
limited meter service resources here
• These customers represent a
disproportionately large amount of the overall
revenue for every utility in North America.
• For some utilities the ten percent of their
customers who have transformer rated
metering services can represent over 70% of
their overall revenue.
• While these numbers will vary from utility to
utility the basic premise should be the same
for all utilities regarding where Meter Services
should focus their efforts
• This is perhaps one of the larger benefits that
AMI can provide for our Utilities – more time
to spend on C&I metering and less on
residential
Easy Answer: Money.
27. Slide 27
Potential list of tasks to be completed during a Site
Veriification of a Transformer Rated Metering SIte
• Double check the meter number, the location the test result and the meter record
• Perform a visual safety inspection of the site. This includes utility and customer equipment. Things
to look for include intact down ground on pole, properly attached enclosure, unwanted voltage on
enclosure, proper trimming and site tidiness (absence of discarded seals, etc.)
• Visually inspect for energy diversions (intentional and not). This includes broken or missing wires,
jumpers, open test switch, unconnected wires and foreign objects on meters or other metering
equipment. Broken or missing wires can seriously cause the under measurement of energy. A
simple broken wire on a CT or VT can cause the loss of 1/3 to 1/2 of the registration on either 3
element or 2 element metering, respectively.
• Visually check lightning arrestors and transformers for damage or leaks.
• Check for proper grounding and bonding of metering equipment. Poor grounding and bonding
practices may result in inaccurate measurements that go undetected for long periods of time.
Implementing a single point ground policy and practice can reduce or eliminate this type of issue.
• Burden test CTs and voltage check PTs.
28. Slide 28
Site Verification Checklist (cont)
• Verify service voltage. Stuck regulator or seasonal capacitor can impact service voltage.
• Verify condition of metering control wire. This includes looking for cracks in insulation, broken wires,
loose connections, etc.
• Confirm we have a Blondel compliant metering set up
• Compare the test switch wiring with the wiring at the CTs and VTs. Verify CTs and VTs not cross
wired. Be sure CTs are grounded in one location (test switch) only.
• Check for bad test switch by examining voltage at the top and bottom of the switch. Also verify amps
using amp probe on both sides of the test switch. Verify neutral connection to cabinet (voltage).
• Check rotation by closing in one phase at a time at the test switch and observing the phase meter for
forward rotation. If forward rotation is not observed measurements may be significantly impacted as
the phases are most likely cancelling each other out.
• Test meter for accuracy. Verify demand if applicable with observed load. If meter is performing
compensation (line and/or transformer losses) the compensation should be verified either through
direct testing at the site or by examining recorded pulse data.
• Loss compensation is generally a very small percentage of the overall measurement and would not
be caught under utilities normal high/low checks. However, the small percentages when applied to
large loads or generation can really add up overtime. Billing adjustments can easily be in the $million
range if not caught early.
29. Slide 29
Site Verification Checklist (cont)
• Verify metering vectors. Traditionally this has been done using instruments such as a circuit
analyzer. Many solid state meters today can provide vector diagrams along with volt/amp/pf and
values using meter manufacturer software or meter displays. Many of these desired values are
programmed into the meters Alternate/Utility display. Examining these values can provide much
information about the metering integrity. It may also assist in determining if unbalanced loads are
present and if CTs are sized properly. The vendor software generally has the ability to capture both
diagnostic and vector information electronically. These electronic records should be kept in the
meter shop for future comparisons.
• If metering is providing pulses/EOI pulse to customers, SCADA systems or other meters for
totalization they also should be verified vs. the known load on the meter. If present test/inspect
isolation relays/pulse splitters for things like blown fuses to ensure they are operating properly.
• Verify meter information including meter multiplier, serial number, dials/decimals, Mp, Ke, Primary
Kh, Kr and Rate. Errors in this type of information can also cause a adverse impact on
measured/reported values.
• Verify CT shunts are all opened.
• Look for signs of excessive heat on the meter base e.g.
melted plastic or discoloration related to heat
30. Slide 30
Periodic Site Inspections…..
….Can Discover or Prevent:
•Billing Errors
•Bad Metering set-up
•Detect Current Diversion
•Identify Potential Safety Issues
•Metering Issues (issues not
related to meter accuracy)
•AMR/AMI Communications Issues
•The need for Unscheduled Truck Rolls
due to Undetected Field Related Issues
•Discrepancies between what is believed to
be at a given site versus the actual setup
and equipment at the site
31. Slide 31
Questions and Discussion
Tom Lawton
TESCO – The Eastern Specialty Company
Bristol, PA
Tom.Lawton@tescometering.com
Cell: 215-688-0298
This presentation can also be found under Meter Conferences
and Schools on the TESCO web site:
www.tescometering.com