Aveneu Park, Starling, Australia

UNIVERSITE different Energy applications and also, provides

 

 

 

 

 

UNIVERSITE DU
HAVRE

MASTERS – RENEWABLE ENERGY AND CIVIL
ENGINEERING (MRECENG)

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SUBMISSION OF ELECTROTECHNICS REPORT

 

BY

 

 

 

 

OMIKE REMIGIUS
CHIMA

2017157308

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

USING THE ENERGY METER AS AN EFFECTIVE ENERGY MANAGEMENT TOOL

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ABSTRACT

Energy Management has proven to be an
essential part of the current drive for more sustainable and efficient
Electrical Energy use for both domestic and industrial applications. The
knowledge of how much KW consumed per hour empowers the Energy user with
information needed to manage the scalability of different Energy applications
and also, provides the enabling environment for Energy Savings procedures. The
aim of this report is to highlight the Energy Management possibilities
available to Energy users.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

FIG.1: SHOWING A TYPICAL INDUCTOR TYPE
ENERGY METER

FIG.
2: DRIVING SYSTEM

FIG.3:
EDDY CURRENTS IN ALUMINIUM DISC DUE TO TIME VARYING FLUX

FIG.
4: PHASOR DIAGRAM OF FLUXES AND EDDY CURRENTS

FIG.
5: TORQUE BALANCE

FIG. 6: INTERNAL SET UP OF THE INDUCTION TYPE ENERGY METER 2

 FIG. 7: PHASOR DIAGRAM OF THE INDUCTOR TYPE

FIG. 8: BLOCK DIAGRAM OF ANALOG ELECTRONIC ENERGY METER

FIG. 9: BLOCK DIAGRAM OF DIGITAL ELECTRONIC ENERGY METER

FIG. 10: SMART ENERGY METERS

FIG 11. SHOWING PROGRESSION OF DIFFERENT TYPES OF ENERGY METERS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TITLE PAGE                                                                                               
                                 2

ABSTRACT                                                                                                                                   3

FIGURES                                                                                                                                      4

TABLE OF CONTENT                                                                                                               
  5

CHAPTER ONE                                                                   
                                                      6
– 8

1.0  Introduction

1.1 Technical Overview Of Energy Meters and Energy Measurements

1.2 Types of Energy Meters

 

CHAPTER TWO                                                                                                                          9 – 12

Electromechanical Induction Energy Meters

 

CHAPTER THREE                   
                                                                                                   13 -14

3.0 Electronic Energy Meters

3.1 Analog Electronic Meters

3.2 Digital Electronic Meters

 

 

CHAPTER FOUR                                                                                                                        15 – 16

4.0 Smart Energy Meters

4.1 Smart Meter Systems In Smart Grid

 

 

CHAPTER FIVE                                                                                          
                                17 – 18

Potential Issues/Errors In Energy Meters

 

CONCLUSION                                                                                                                
               19

 

REFERENCES/BIBLIOGRAPHY                                                                                                     20

 

 

 

 

 

 

 

CHAPTER ONE

1.0 INTRODUCTION

Energy Management forms an integral
part of recent campaigns for more efficient and sustainable Energy Use and
Savings. A major component of Energy Management is the Energy Meter tool, also
known as an Integrating Device. The
simplest definition of an Energy Meter
is that it is an electrical measuring device which provides real time data of
consumed Electrical Energy over a time interval (usually in Watts-hours). It is
also called a watt-hour (Wh) meter. The Energy meter is an instrument which is
mostly installed by utilities in homes, organizations, industries to measure
electricity consumption per loads 2,3. Watts is the unit for Power and 1000
Watts is equal to 1KW. Energy consumed is measured in terms of Kilowatts per
time. Thus, if we use one Kilowatt for one hour, then it means the energy
consumed is 1KWh. Energy
could be expressed as the total power delivered or consumed over an interval of
time t may be expressed as 4:

Where W:
Energy, V= Voltage, i= Current, t= time

 

Energy meters are increasingly
becoming mandatory devices in houses, factories, businesses, shops, offices and
industries. This helps users across different cadres of society to assess how
much power is being consumed to do work. 

 

 

 

 

 

 

 

 

 

 

1.1           
TECHNICAL OVERVIEW OF ENERGY MEASUREMENTS

Modern
Energy meters are designed using fundamental Electricity principles. Therefore,
measurements of both Electrical Power (W) and Electrical Energy (Wh) use
interdependent methods based on principles such as 1:

Ø 
Energy
Measurements in Alternating Current Networks:

W
= P · t

Where W = Energy, P = Power, t = Time

 

Ø 
Power
Measurements in Alternating Current Networks:

Where P = Power, U = Voltage, I =
Current, ? = Phase Angle

 

Ø 
Power
Measurements in 3-phase systems:

Where P = Power, U = Voltage, I = Current

 

Ø 
Power
Measurements in Load Balanced 3-phase systems:

Where P = Power, UNPD
= Neutral- Point Displacement Voltage, I
= Current

Ø 
Delta-Voltage
Neutral-Point Displacement Voltage

 

Where UNPD = Neutral- Point Displacement Voltage

 

Ø 
Deriving
the Factor (?3):

The
derivation below is obtained using cosine law and the angular relationships
demonstrated by the voltage triangle as shown:

 

 

 

 

 

If the
above equation (3) is applied to the power equation, (1) or (2),
the following results:

 

 

 

1.2 TYPES OF ENERGY METERS

Energy
meters come in different types. They are however classified according to the
following factors:

Ø  Type
of metering point (Grid modes, secondary transmission, primary and local
distribution networks)

Ø  Display
type (Analog or Digital Display Energy Meter)

Ø  End-User
Applications (Domestic, Commercial or Industrial)

Ø  In
Terms of Phases (Single Phase, 3-Phase, High Tension, Low Tension and Accuracy
Class Meters).

Usually,
the single or 3-phase Energy Meters are used relative to the power supply type.
For domestic installations (or small service measurements), the Energy meter is
directly connected between the line and the load. However, for larger-scale installations,
step down current transformers must be used in between the line and the load to
isolate Energy meters from damage resulting from exposure to higher currents. In
the context of this report, we will consider 3 types of Energy Meters namely:

Ø  Electromechanical
Induction Energy Meters

Ø  Electronic
energy Meters

Ø  Smart
Energy Meters 5.

 

CHAPTER TWO

2.0           
 ELECTROMECHANICAL INDUCTION ENERGY METERS

 

This is
the earliest form of the Watt hour meter. It houses a system that comprise
rotating Aluminium disc fixed on a spindle between 2 electromagnets. The disc’s
rotation speed is proportional to the power, where power is integrated using a
counter mechanism and gear trains. The Electromagnets used are silicon steel
laminated and designed as shunt and series magnets. While the shunt magnet
carries a coil of many wire turns, the series magnet bears a coil of few wire
turns. The system also houses a brake magnet (permanent magnet), which applies
a force opposite to the normal disc rotation such that it moves at a balanced
position and halts the disc while power is turned off. One limitation of this
type of energy meter is their susceptibility to external tampering 5.

 

 

FIG.1: SHOWING A
TYPICAL INDUCTOR TYPE ENERGY METER

 

HOW IT WORKS

The
induction type energy meter (mostly single-phase) comprise a driving system,
moving system, braking system and registering system.

 

Driving
System: Contains the
laminated electromagnets (M1 and M2). M1 is called the series magnet and M2 is
the shunt magnet. The coil in M1 is connected in series with the circuit and current
through this coil is called Current Coil (CC). Load current flows through M1.
Also, the coil in M2 is called the Voltage Coil (VC) and this is connected
across the power supply used. The current in VC is proportional to the Supply
Voltage. The lower part of the central limb of M2 is short circuited with
copper elements called Power Factor Compensator. The flux from M2 lags behind
the Supply Voltage by 90 degrees when the loop positions is adjusted. The
copper elements also provide compensation due to friction.

 

 

 

 

FIG. 2: DRIVING SYSTEM 4

 

 

 

Moving
System: This is simply a
thin Aluminium disc mounted on a spindle and is fixed in the air gap between M1
and M2. This mechanism cuts the flux from M1 and M2 magnetic forces with
induced eddy current in the disc. Both forces act as the deflecting torque.

 

 

FIG.3: EDDY CURRENTS IN ALUMINIUM DISC DUE TO TIME VARYING FLUX
4

 

 

 

FIG. 4: PHASOR DIAGRAM OF FLUXES AND EDDY CURRENTS 4

 

 

 

 

 

Braking
system: This
system houses the brake magnet which is situated near the disc’s edge. As the
disc rotates within the magnetic field, eddy currents are produced and these
currents react with the magnetic flux to give a torque effect. The created
torque opposes the disc motion, and therefore, the resulting brake torque is
proportional to the rotational speed of the disc.

 

FIG. 5: TORQUE
BALANCE 4

 

 

Registering
System: Consist of a counting mechanism attached to the disc spindle. The
counting mechanism acts as a register for recording numbers and these numbers
correspond to the number of disc revolutions. The mechanism is scaled to
display energy consumption measured in Kilo Watts-Hour 5.

 

 

 

 

 

 

 

 

 

 

FIG.
6: INTERNAL SET UP OF THE INDUCTION TYPE ENERGY METER 2

                                FIG. 7: PHASOR DIAGRAM OF
THE INDUCTOR TYPE 2

 

CHAPTER THREE

 

3.0 ELECTRONIC ENERGY METERS

Electronic
Energy meters are more accurate, reliable and have higher precision compared to
the induction type Energy meters. They use less power and begin instantaneous
measurement when connected to Energy loads. Electronic Energy Meters are
designed based on Digital Micro Technology (DMT) and unlike the induction type
energy meters, they have no need for moving parts. Thus the Electronic Energy meter
can be best described as a static instrument which functions based on
integrated circuit applications. Two types of Electronic Energy Meters exist:
Analog and Digital Electronic Meters5.

 

 

ANALOG ELECTRONIC METERS

FIG.8
: BLOCK DIAGRAM OF ANALOG ELECTRONIC ENERGY METER

In this type of Electronic meter, power is converted
into frequency or pulse rate. Using Voltage Divider rule, the analog meter
measures the voltage for each phase. Also, using Current transformers, the
current for each phase is calculated. ADC (Analog-to-Digital Converters)
transforms the input signals into to digitized forms, and this is further
converted into corresponding frequency signals using a frequency converter. The
pulse rates drive a counter mechanism where pulses are integrated with respect
to time to produce energy consumption rates as displayed on the instrument’s
scale.

 

3.1 DIGITAL ELECTRONIC ENERGY METERS

FIG.
9: BLOCK DIAGRAM OF DIGITAL ELECTRONIC ENERGY METER

Digital
Electronic meters are designed to include high-end digital signal processors,
voltage and current transducers. These transducers are connected to high
resolution Analog-to-Digital Converter, which convert analog input signals into
digital samples. These samples are multiplied and integrated by logic circuits
to measure energy consumption 5.  

The
digital signal processor (DSP) measures the phase angle between voltage and
current, and this functionality make it possible to calculate Reactive Power.
The DSP contains a real time clock which is used for time calculations with
respect to power integration, date/time stamps for some parameters and maximum
demand computations. Programming the DSP enables energy calculations based on
tariff and the values are stored in a non-volatile memory.

 

 

 

 

 

 

 

CHAPTER FOUR

 

4.0 SMART ENERGY
METERS

 

 

FIG.
10: SMART ENERGY METERS

 

Smart
Energy Meters operates an intelligent electronic measurement system which
reads, processes and transmits feedback data to Energy users. It has capacity
to perform energy measurements while conducting remote switching functions to
regulate supply for efficient electricity consumption. The high-end technology
used by Smart meters allows for dual communication modes. This 2-way
communications technology for monitoring and controlling information is known
as Advanced Metering Infrastructure (AMI). Initially, Automated Meter Reading
(AMR) systems was used to provide one-way communications for collecting meter
data. AMI is the offshoot of research efforts towards substituting AMR . Information
can be either sent or received over effective communication systems between
utilities and users. In the use of smart metering, it is highly unlikely to see
cases of meter tampering 11.

 

 

 

 

 

 

 

 

 

 

4.1 SMART METER SYSTEMS IN SMART GRID

Smart
Meters play crucial roles in current Smart Grid networks offering seamless
possibilities in meter data collection and communications. A typical Smart Grid
infrastructure automates virtually every segment of the Electrical grid, and
this system allows monitoring and control of grid activities towards ensuring
efficient and reliable dual flow of Electricity and information between power
plants and consumers and intermediate points. In conjunction with smart meters,
the Smart Grid tracks both power delivery and consumption whereby relevant
energy information is sent to utilities using communication networks. Customers
can also monitor their energy use via the internet or computer programs11.

 

4.2 TYPES OF SMART METER SYSTEMS

Smart Systems have 2 types and both
are based on LAN (Local Area Network) technology. They are:

Ø  Power Line Carrier Meter System 11

Ø  Radio Frequency Meter System 11

Each system has inherent merits and
demerits in terms of application. Utilities play vital roles in the choice of
smart meter systems to use. Some factors which determine the selection of any
of the available systems include:

Ø  Functionality

Ø  Evaluation of existing infrastructure

Ø  Economic impact to customers

Ø  Technical requirements 11.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CHAPTER FIVE

 

POTENTIAL ISSUES/ERRORS
IN ENERGY METERS

Each
energy meter type has potential issues or errors depending on the how it was
designed or built. The potential issues are highlighted as follows:

 

1. COMMON ISSUES/ERRORS IN ELECTROMECHANICAL INDUCTION TYPE ENERGY
METER:

In
a case where supply voltage and frequency are constant, the induction type
energy will have the following issues/errors:

          

Ø Speed Error:

This occurs due to wrongly positioned brake
magnet. Therefore the torque is poorly developed. Speed error can be detected
when the meter is allowed to run on full load current or a situation where the
meter runs on loads of unity power factor and reduced lagging factor. By
changing the position of the brake magnet towards the disc center or away from
the disc center and the shielding loop, the rotational speed is adjusted to obtain
a correct value. When the meter runs swiftly on inductive load and
appropriately on non-inductive load, the shielding loop must be moved towards
the disc. From an opposite perspective, when the meter runs slowly on a
non-inductive load, the brake magnet moves towards the disc center.

Ø Meter Phase Error

This becomes possible when a wrong adjustment
of the shading band position causes a wrong phase displacement between the
magnetic flux and the supply voltage. Phase error is tested using a 0.5 power
factor load at the rated load condition. Varying the copper shading band
position in the central limb of the shunt magnet could eliminate this error.

Ø Friction Error

Using
an extra amount of driving torque could compensate for this error. Varying the
2 shading bands on the limbs help to create this extra torque. This adjustment
occurs at low loads (at about 1/4th of full load at power factor of 1).

 

Ø Creep:

When
meters observe a slow but constant revolution due to excitement of the pressure
coil (despite the absence of load current flowing), creep error is said to
occur and usually involves some energy stored from the rotational motion
observed. The rotational movement results from factors like:

·        
Wrong
friction compensation

·        
Stray
magnetic field

·        
Over
voltage across the voltage coil.

           

Boring
slots in the disc on the opposite side of the spindle could remove creep error.

 

Ø Temperature Effect:

This happens
frequently and is majorly because of temperature changes. Temperature equally
impacts the driving and braking torques. Increasing temperature raises the
resistance of the induced-current path in the disc, and this results in error.
Although the error could be taken as negligible, but current energy meters have
compensation mechanisms built as flux dividers on brake Magnet.

 

Energy meter
constant K = No. of revolutions / kwh

Most
commercial meters have disc rotation speed at 1800 revolutions per hour in full
load.

 

Ø Frequency Error

 

 

 

 

 

 

2. COMMON ISSUES/ERRORS IN ELECTRONIC ENERGY METERS

Ø  False
energy readings higher than the actual value 6, 9.

Ø  Errors
due to electromagnetic interference 10.

 

 

 

 

 

 

 

3. COMMON ISSUES/ERRORS IN SMART ENERGY METERS

Ø  Concerns
with Meter Accuracy owing to weather conditions.

Ø  Radio Frequency (RF) Exposure

Ø  Smart Meter Security With Respect To Data Protection
11

 

 

 

 

 

 

 

 

 

 

 

CONCLUSION

 

 

Energy
Meters have eased the energy transition process and has helped to cut down on
energy waste situations over the years. Also, it has helped individuals,
building owners, companies and utilities get accurate energy information which
in turn fast tracks efforts to ensure efficient energy delivery and energy use.

 

In
addition, we observed that there has been progressive developments for the
different types of Energy meters with significant improvements in their operations.

 

 

 

 

 

 

 

 

 

 

 

 

FIG 11. SHOWING
PROGRESSION OF DIFFERENT TYPES OF ENERGY METERS

 

 

 

 

 

In summary, Energy Meters have created
the much needed platform for accountability and responsibility from both Energy
providers and Energy consumers. This evens out the disparities and opens the
channel for more proactive measures in tackling the World’s electricity
challenges.

 

 

 

 

 

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