AC SMART MEASURING POWER DEVICE
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Transcript of AC SMART MEASURING POWER DEVICE
AC SMART MEASURING POWER DEVICE
Chapter 1:
1
Chapter 2: ContentsList of Symbols and Abbreviations................................................................................5
Acknowledgments..........................................................................................................6
Abstract..........................................................................................................................7
CHAPTER 1: Introduction.............................................................................................8
1.2 Problem Statement:............................................................................................10
1.3 Project Scope..................................................................................................10
1.1 The Meter Design is divided into the following modules:............................12
Chapter 2: Theory....................................................................................................13
2.1 Testing and Construction...............................................................................13
2.2 Arduino (UNO):............................................................................................15
LED..........................................................................................................................16
2.3 Voltage transformer.......................................................................................17
2.4 Current transformers......................................................................................18
2.5 Power Factor..................................................................................................19
2.6 Split core transformer....................................................................................21
2.7 Global System Mobile...................................................................................22
2.8 Printed Circuit Board.....................................................................................23
Chapter 3: Procedure................................................................................................24
3.1 Working Explanation,....................................................................................24
Procedure..............................................................................................................24
3.1.1 Description:............................................................................................27
3.1.2 The Code:...............................................................................................28
Chapter 4: Conclusion..............................................................................................31
Chapter 5: References..............................................................................................32
2
3
List of Symbols and Abbreviations
Symbols Abbreviations
1 GSM global system for mobile communication
2 CT Current Transformer
3 VT Voltage Transformer
4 KWH power factor and energy in units of Kilowatt-Hours
5 v Unite of volts
6 A Unit of amperes
7 SIM subscriber identity module
8 SMS short message service
9 LCD light-emitting diode
10 AC Alternating Current
11 CT split-core current transformer.
12 rms root mean square
13 C Programing languages.
14 C++ Programing languages.
15 Pf Power factor
16 MCU Multipoint Control Unit
Please insert here any symbols and abbreviations that you commonly use in your
report.
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AcknowledgmentsFirst, we would like to thank our supervisor of this project, Eng.Shuaib for his
valuable guidance and advice. He guided us greatly to work in this project. He is
willingness to motivate us helped tremendously. Next we would like to thank the
University for providing us with a good environment and facilities to complete this
project. It gave us an opportunity to participate and learn about the operation of Smart
Electrical Energy Monitor & Metering Device. Finally, an honorable mention goes to
our families and friends for their understanding and support in completing this
project. Without help of those mentioned above, this project could not have been
completed.
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Abstract
Energy efficiency in the UAE is a growing challenge due to the ever increasing
penetration of personal appliances and an unsustainably high consumption of
electrical energy. Electrical efficiency ratings provided by the manufacturers, based
on ideal operating conditions, is an important criterion commonly used by consumers
when purchasing appliances and electrical machines. We are proposing a versatile,
highly scalable and portable smart electrical energy monitoring and metering device.
We will design and prototype a single-phase, software-defined energy monitoring
system with the aid of an embedded processor and the wireless GSM communication
protocol. In contrast to simple contact based voltage and current measurement
mechanisms, the proposed sophisticated and portable embedded device will be driven
by a contact-less split core Current Transformer (CT) and a generic Potential
Transformer (VT). Based on the sensed single phase voltage and current variables, the
device will calculate and communicate, in real time, the key electrical energy
parameters of average power, power factor and energy in units of Kilowatt-Hours
(kWH) over a user-defined period of time. The calculated parameters are
communicated to the consumer over the wireless GSM protocol. The calculated
parameters can then be used to benchmark numerous single phase electrical.
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CHAPTER 1: Introduction
Energy Meter is a device that measures the amount of electrical energy consumed by
a residence, business, or an electrically powered device. They are typically calibrated
in billing units and the most common one is the kilowatt hour, which is equal to the
amount of energy used by a load of one kilowatt over a period of one hour, or
3,600,000 joules. Electricity meters operate by continuously measuring the
instantaneous voltage (v) and current (A). The product of which gives the
instantaneous electrical power (watts) which is then integrated against time to give
energy used.
Energy Meter devices is a unique concept, in which the electricity board can collect
the consumed units’ data from consumer on mobile phone using GSM network. Each
consumer is provided with a unique energy meter, which is having a GSM modem,
microcontroller unit and a display unit. An SIM (subscriber identity module) card is
required for communication. Whenever this system receives an SMS (short message
service) from electricity board, it calculates the number of units consumed and billing
amount on the prevailing rate, displays on LCD for user interface. This system also
sends the same message to the electricity board for departmental information and
database.
Domestic electrical energy consumption in the UAE has double over the decade and
continues to outstrip the global average growth in consumer energy demand.
Economic activity and population growth might be important contributing factors but
the energy efficiency of house-hold consumers, that form the bulk of the gross
demand, is an often over-looked parameter. The efficiency claims of the most
commonly used electrical machines are often misguiding and contribute to the high
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consumption rates. In light of the problem, a smart energy monitor and metering
device is proposed
1.1 Objectives:
* Design and prototype a software-defined electrical energy monitor and metering
device using a contact-less and safely operated current transformer and a wall-socket
potential transformer.
* Integrate an appropriate embedded GSM data relay system using a microcontroller
to convey energy data signals to the consumers.
* Utilize the collected and interpreted data to benchmark efficiency ratings of the
devices.
* Utilize the collected data to predict the operating energy costs of the benchmarked
devices.
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1.2 Problem Statement:
Most conventional prepaid energy meters currently installed in households only
display the total real time usage of its power and the amount of electricity available.
There is no way to see what the day’s, week’s or month’s consumption was on these
meters and often these power meters are placed in an inconvenient location which
makes regular viewing somewhat difficult. These Energy meters also lack the ability
to monitor appliances individually; thus hiding vital information about individual
appliances.
1.3 Project Scope
A Smart Meter System is required which can analyze multiple appliances in a
household getting readings such as voltage, current, active power, apparent power,
reactive power, power factor and frequency. With the help of a wired / wireless
connection, the device can connect to a central gateway and the gathered information
can be uploaded and processed by the gateway management system. The data can
then be displayed on the platform’s graphical android-based user interface. The
platform allows users to access the data from any android enabled device. To reduce
cost, the system requires energy metering nodes that can communicate with the
gateway wirelessly or in wired way in such a way that only one Wi-Fi access point is
needed for a household containing many monitored appliances. Furthermore, it is
required that the current information regarding the appliances can also be viewed on a
local display with a menu interface. The remote energy metering node will be
considered to be successful if the following criteria are met:
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• Wired/wireless communication between nodes and gateway
• Correct measurements of Voltage, Current and Power
• A working user interface on the gateway with a display and menu
• Reliable wired/wireless communication between gateway and remote meter nodes.
If time permits, the following additional features may be added so as to improve the
project, keeping in mind that omission of these features will not affect operation:
• Building safe mechanical structure to package the gateway station
• Building safe mechanical structure to isolate the energy metering nodes
• To increase power efficiency of the device and to minimize power usage when
appliance is turned off
2.1 The Meter Design is divided into the following modules:
The voltage sensing module.
The current sensing module.
The metering chip.The main microcontroller.The display module.
The communications module.The power supply system Meter design block diagram.
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The meter was implemented using Arduino to measure the voltage and current and
integrating the product over time to give the energy usage. The microcontroller is also
the central system that interfaces with the meter, the LCD screen and the GSM
modem as shown in. The microcontroller was programmed with the Arduino using C
and C++-languages.
Chapter 3: Theory
3.1 Testing and Construction
The microcontroller calculates the energy value by integrating the value of Power
over time by using the fundamental formula of Energy = Power × Time.
The microcontroller also sends the output or energy consumed to the LCD screen via
the output pins for display. The microcontroller receives the SMS messages from the
GSM Modem and interprets it using the MCU command set. The microcontroller
performs the following actions depending on the SMS message:
Add credit units to the meter;
Send out an SMS Message with the balance or send a signal to the relay to
disconnect the meter;
The microcontroller can both send and receive SMS messages via the GSM modem.
The display module is viewed through a 16 × 2 crystal display screen. The
communication module uses mobile device communication system.
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The relay/switch off module controls the customer’s connects and disconnect
operation of the meter. Power supply unit energizes the microcontroller, relay and
GSM module of the meter system.
Microcontroller is a small computer (SoC) on a single integrated circuit that contains
a processor core(s), memory and programmable input/output peripherals. Program
memory in the form of Ferroelectric RAM, NOR flash or OTP ROM is also often
included on chip, as well as a typically small amount of RAM. Microcontrollers are
designed for embedded applications, in contrast to the microprocessors used in
personal computers or other general purpose applications consisting of various
discrete chips.
Microcontrollers are used in automatically controlled products and devices, such as
automobile engine control systems, implantable medical devices, remote controls,
office machines, appliances, power tools, toys and other embedded systems. By
reducing the size and cost compared to a design that uses a separate microprocessor,
memory, and input/output devices, microcontrollers make it economical to digitally
control even more devices and processes. Mixed signal microcontrollers are common,
integrating analog components needed to control non-digital electronic systems. They
are mainly used in products that require a degree of control to be exerted by the user.
.
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Figure (1): microcontroller
3.2 Arduino (UNO):
Arduino is an open-source platform used for building electronics projects. Arduino
consists of both a physical programmable circuit board (often referred to as a
microcontroller) and a piece of software, or IDE (Integrated Development
Environment) that runs on your computer, used to write and upload computer code
to the physical board. The Arduino platform has become quite popular with people
just starting out with electronics, and for good reason. Unlike most previous
programmable circuit boards, the Arduino does not need a separate piece of
hardware (called a programmer) in order to load new code onto the board – you can
simply use a USB cable. Additionally, the Arduino IDE uses a simplified version of
C++, making it easier to learn to program. Finally, Arduino provides a standard
form factor that breaks out the functions of the micro-controller into a more
accessible package. The Uno is one of the more popular boards in the Arduino
family and a great choice for beginners.
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Figure (2): Arduino Board
LED:
A light-emitting diode (LED) is a two-lead semiconductor light source. It is a p–n
junction diode, which emits light when activated.[4] When a suitable voltage is applied
to the leads, electrons are able to recombine with electron holes within the device,
releasing energy in the form of photons. This effect is called electroluminescence, and
the color of the light (corresponding to the energy of the photon) is determined by the
energy band gap of the semiconductor.
An LED is often small in area (less than 1 mm2) and integrated optical components
may be used to shape its radiation pattern. Appearing as practical electronic
components in the earliest LEDs emitted low-intensity infrared light. Infrared LEDs
are still frequently used as transmitting elements in remote-control circuits, such as
those in remote controls for a wide variety of consumer electronics. The first visible-
light LEDs were also of low intensity, and limited to red. Modern LEDs are available
across the visible, ultraviolet, and infrared wavelengths, with very high brightness
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Figure (3): LED
3.3 Voltage transformer
Voltage transformer which is also called as a potential transformer. It employed in
electrical energy power system for stepping down the voltage of the system to some
protected value which is often provided to low rating meters and relays.
Commercially accessible relays and meters utilized for coverage and metering are
prepared for low voltage, so the potential transformer is normally used for stepping
down the voltage in distribution systems. But it can be used to step up the voltage as
well. In transmission lines where the sole aim is to minimize the line losses, potential
transformer serves the purpose, it steps up the voltage so that line losses can be
avoided as much as can. Therefore, usually in transmission lines, voltages are very
high. In the case of the typical step-down transformer. A voltage transformer concept
or potential transformer concept is the same as a theory of basic step down
transformer. Between the phase and the ground primary of the voltage transformer is
connected. Voltage transformer has lower primary turns than its secondary windings,
for the purpose of stepping down. The voltage of the system is applied over the
terminals of the primary winding of that transformer, after which secondary voltage
appears in proper proportion over the secondary terminals of the potential
transformer.
Normally the secondary voltage is 110 volts. The ideal voltage transformer is one in
which the ratio of primary and secondary voltages is same as the turn ratio, as turn
ratio is the ratio of the primary and secondary wire turns and it decides the function of
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the transformer as step up or step down. But in actual transformers phase angle
between the secondary and primary voltage vary and voltage ratio gives an error.
Phasor diagrams help in understanding those errors.
Figure (4): Voltage transformer
3.4 Current transformers
Current transformer which is often referred as CT regulates alternating current i.e on
its secondary terminal alternating current is proportional to the value of current on its
primary. A current transformer is normally used to provide isolated lower current on
its secondary terminals. Current transformers are utilized broadly for the purpose of
computing current and checking the whole process of the power grid. Together with
voltage prospects, revenue-grade Current transformers force the electric powered
utility’s watt-hour gauge on practically every building with three-phase services and
single-phase services more than Two hundred amperes. Transformers with High-
voltage current are attached to porcelain ceramic or polymer bonded insulators to
segregate them from the ground. Several CT designs slip across the bushing of the
high-voltage transformer or even circuit breaker, which immediately facilities the
conductor within the CT window. Current transformers could be attached to the lower
voltage or even high voltage prospects of a power transformer. Current transformers
can be used to keep an eye on dangerously higher currents or currents at risky high
voltages, so excellent proper care should be ingested the structure and use of CTs
during these scenarios. The secondary of an existing transformer really should not be
turned off from the load while current is within the primary, as the secondary will
endeavor to carry on driving current into a highly effective limitless impedance as
much as its insulation breakdown voltage and, therefore, give up operator safety.
Current transformers decrease high voltage currents to some reduced value and supply
a handy method of properly checking the particular electric powered current moving
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within an AC transmission line utilizing a standard ammeter. The key operation of the
current transformer is absolutely no different from those of a regular transformer.
Figure (5): Current transformer
3.5 Power Factor
Power factor is a single number that relates the active power, P, to the apparent
power, U. Electric components of a utility distribution system are designed on a kVA
basis; i.e., they are designed to operate at a given voltage and carry a rated current
without undue temperature rise. Transformer and conductor sizes are chosen on this
basis. While active power does useful work, reactive and harmonic powers do no
useful work, absorb system capacity, and increase system losses; but reactive and
harmonic powers are needed to provide magnetic fields or nonlinear currents. The
capacity of electric systems is limited by apparent power, not active power. Power
factor expresses, with a single value, the extent to which an electrical distribution
system is efficiently and effectively utilized. A low value for the power factor means
that much of the system capacity is not available for useful work.
Phasor diagram for a single-phase, non-sinusoidal service in which the voltage and
current contain harmonics. Geometric relationships are shown between active,
reactive, phasor, distortion, and apparent powers.
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Figure (): Phasor diagram for a single-phase
Figure(4): Power Factor Diagram
The phase angle of the load impedance plays a very important role in the absorption
of power by a load impedance. As illustrated in this equation:
And in the previous equation, the average power dissipated by an AC load is
dependent on the cosine of the angle of the impedance. To recognize the importance
of this factor in AC power computations, the term cos(θ ) is referred to as the power
factor (pf). Note that the power factor is equal to 0 for a purely inductive or capacitive
load and equal to 1 for a purely resistive load; in every other case, 0 < pf < 1 . Two
equivalent expressions for the power factor are given in the following:
Pf = cos(θ ) = Pav / V˜ ˜I
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Table (1): Power Factor
Where V˜ and ˜I are the rms values of the load voltage and current, respectively.
The distortion power factor is the distortion component associated with the harmonic
voltages and currents present in the system.
THD is the total harmonic distortion of the load current. I1,rms is the fundamental
component of the current and Irms is the total current distortion. In practice, the local
effects of distortion current on devices in a three-phase distribution network rely on
the magnitude of certain order harmonics rather than the total harmonic.
3.6 Split core transformer
A split core transformer, which is also called CT “Current Transformer “sensor, is a
device that is used for a continuous energy monitoring purpose. This current
transformer CT works by connecting it to an AC power line, thus will detect the flow
of the current through the wire. When the current flow through the wire it creates a
magnetic field in CT sensor core the secondary wire winding around this core will
creates a smaller current that is proportional to the load on the wire. Our project is an
Arduino based one, so In order to connect this Current transformer with a small
resistor to generate voltage output.
A spilt core transformer has many advantages for example:
Allows installation without a power shut down.
Requires less labor for monitoring.
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Figure(5): Split core transformer
3.7 Global System Mobile
GSM is a mobile communication modem; it is stands for global system for mobile
communication (GSM). The idea of GSM was developed at Bell Laboratories in
1970. It is widely used mobile communication system in the world. GSM is an open
and digital cellular technology used for transmitting mobile voice and data services
operates at the 850MHz, 900MHz, 1800MHz and 1900MHz frequency bands. GSM
system was developed as a digital system using time division multiple access
(TDMA) technique for communication purpose. A GSM digitizes and reduces the
data, then sends it down through a channel with two different streams of client data,
each in its own particular time slot. The digital system has an ability to carry 64 kbps
to 120 Mbps of data rates.
There are various cell sizes in a GSM system such as macro, micro, Pico and umbrella
cells. Each cell varies as per the implementation domain. There are five different cell
sizes in a GSM network macro, micro, pico and umbrella cells. The coverage area of
each cell varies according to the implementation environment.
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Figure (): GSM
Figure (6): Global System Mobile
3.8 Printed Circuit Board
The printed circuit board (PCB) mechanically supports and electrically connects
electronic components using conductive tracks, pads and other features etched from
copper sheets laminated onto a non-conductive substrate. Components – capacitors,
resistors or active devices – are generally soldered on the PCB. Advanced PCBs may
contain components embedded in the substrate. PCBs can be single sided (one copper
layer), double sided (two copper layers) or multi-layer (outer and inner layers).
Conductors on different layers are connected with vias. Multi-layer PCBs allow for
much higher component density.
Today printed wiring (circuit) boards are used in virtually all but the simplest
commercially produced electronic devices, and allow fully automated assembly
processes that were not possible or practical in earlier era tag type circuit assembly
processes. A PCB populated with electronic components is called a printed circuit
assembly (PCA), printed circuit board assembly or PCB Assembly (PCBA). In
informal use the term "PCB" is used both for bare and assembled boards, the context
clarifying the meaning. The IPC preferred term for populated boards is CCA, circuit
card assembly. This does not apply to backplanes; assembled backplanes are called
backplane assemblies by the IPC.
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Figure(): PCB
Figure (7): Printed Circuit Board
Chapter 4: Procedure
4.1 Working Explanation,
Here we have interfaced electricity energy meter with Auridon using the pulse LED
of power energy meter.
Component used:
1. Arduino
2. GSM
3. Analogue Electricity Energy Meter
4. Resistors
5. Connecting wires
6. Power Supply
Procedure:
The electrical board of the Smart-plug device should be designed and implemented
for testing, including both hardware design and software design. For the hardware
part, the electrical circuit design including the current and voltage transformers design
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and the selection of the resistors, LED and Arduino board. However, the software task
is to make programming for electrical circuit to make sure that our device achieve the
expected targets successfully
First of all, we set up the wire connections and measures the value of each resistor.
Figure(8): Measuring the value of Resistors
After that, we built the circuit and added diodes, microcontroller and the power
supply.
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Figure (9): Measuring the value of the resistor
When the current = 0.3A the signals was monitoring 270mv, and at 0.345A the
signals monitored 310mv. As we can noticed there is a proportional and linearity
relationship between the voltage and the current whereas the resistors were almost
constant.
Figure(10): Oscillated Data
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4.1.1 Description:
With the measurement and visualization of the system power and energy consumption
by using the AC smart system, the customer can know the energy consumption value
in a room or wherever instantly and directly then can manage the power use of the
place easily and conveniently. It was hoped that this tool would raise the awareness of
how much energy the person use and make users more energy efficient. Power Meter
was intended for use with smart meters able to track electricity usage in more detail
than standard electric meters.
Figure (11): AC Power Meter
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4.1.2 The Code:#include <math.h>
volatile double voltage[20], current[20];
double Vrms = 230;
volatile double Irms = 0;
volatile double avgPower = 0;
volatile int flag = 0;
int cycleCount = 0;
double cycleAvgPower[10];
#define pi 3.1412
#define wd (2*pi/20)
#define phi (15*pi/180)
#define N 20
double appPower = 0;
double powerFactor = 0;
void setup()
{
Serial.begin(9600);
while (!Serial);
// initialize timer1
noInterrupts();
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// disable all interrupts
TCCR1A = 0;
TCCR1B = 0;
TCNT1 = 0;
OCR1A = 250;
// compare match register 16MHz/64/1000Hz
TCCR1B |= (1 << WGM12); // CTC mode
TCCR1B |= ((1 << CS10) | (1 << CS11)); // 64 prescaler
TIMSK1 |= (1 << OCIE1A); // enable timer compare interrupt
interrupts(); // enable all interrupts
}
void loop()
{
if (flag == 1) {
/// noInterrupts();
Vrms = sqrt((Vrms / N));
Irms = sqrt((Irms / N));
appPower = Vrms * Irms;
avgPower = avgPower / N;
powerFactor = avgPower / appPower;
cycleAvgPower[cycleCount] = avgPower;
cycleCount++;
avgPower = 0;
Vrms = 0;
Irms = 0;
/* Serial.print("Vrms = ");
Serial.println(Vrms);
Serial.print("Irms = ");
Serial.println(Irms);
for (int j = 0;j<20;j++){
Serial.print("voltage = ");Serial.println(voltage[j]);
}
Serial.print("Average power = ");
Serial.println(avgPower);
Serial.print("Power factor = ");
27
Serial.println(powerFactor); */
flag = 0;
if (cycleCount == N) {
noInterrupts();
TIMSK1 &= ~(1 << OCIE1A); //disable timer interrupts
for (int j = 0; j < N; j++) {
Serial.println(cycleAvgPower[j]);
}
}
}
}
ISR(TIMER1_COMPA_vect) // timer compare interrupt service routine
{
static unsigned char i = 0; //non-volatile to keep track of index
current[i] = (analogRead(A0)-511);
//analogRead(A1);
//voltage[i] = 230 * sin(wd * i);
//current[i] = 0.5 * sin(wd * i - phi);
avgPower += voltage[i] * current[i];
Vrms += voltage[i] * voltage[i];
Irms += current[i] * current[i];
i++;
if (i == N) {
i = 0; flag = 1;
//noInterrupts();
//TIMSK1 &= ~(1 << OCIE1A);
}
}
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Chapter 5: ConclusionThis thesis has introduced smart meter home automation system and the complement
of developing smart meter shields as advantage of accuracy and stable ability. Solid
state relay for smart meter has successfully applied in working condition. Different
measurement methods have showed in the thesis. There is no absolutely perfect thing
exist in the world, which stimulus us always exploring more efficient new methods to
develop our products.
Microcontroller is a key factor for the power meter due to its stability and powerful
function. There are still a lot of aspects can be developed. In the future smart meter
can integrate into smart appliances not only household application, but also industrial
area. Also new technology can use and replace the old one. Such as KNX standard
has higher requirement of smart meter application and also hard-ware design. Some
problems occurred during the testing part. We always need to learn new technology to
enhance ourselves.
This is a very practical project as a thesis. In the future, a wireless control module and
link to national smart grid can be built up. The automation system can add more
sensors that have more functions work for our life everywhere. I do believe our world
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will become smarter and electrical based efficient life style.
Advancement in technology has provided means of effectively measuring and
monitoring energy. Such technology has been achieved in this work by employing a
modem and SIM card interface. A single phase energy meter with remote monitoring
and energy token generation capability using SMS has been designed, modeled and
constructed. The entire design has been implemented on a locally made single layer
PCB. This design will address energy metering problem and help improve the billing
systems with added advantage of remotely monitoring energy usage.
30
Chapter 6: References
[1] Sambo AS, Renewable Energy for Rural Development: The Nigerian
Perspective. ISESCO Science and Technology Vision 2005;1: 12-22.
[2] Bulbenkiene V, Pecko A, Zulkas E, Kuprinavicius A, Sokolov A and
Mumgaudis G, Energy Sub-Metering Data Acquisition System. Electronics
and Electrical Engineering 2011; 5(111): 99-102
[3] Balakrishna, 2009. World Meter Design Corporation. [Online] Freescale
semiconductor Productions Available at: http://freescale.com [Accessed 8
August 2011].
[4] Nwaoyo I, Design and Construction of a Smart Card Based Single Phase
Meter. Final Year Project. Department of Electrical and Information
Engineering, Covenant University 2011.
[5] Lanphur C, Electric Meter history and Progress. Handbook. Westinghouse
Press 1925.
[6] SO/IEC, 2006. International Standard Organization. 3rd ed. IEC press.
[7] Analog Devices Inc., 2002. Energy Metering Ic with Pulse Output. Data
Sheet, 13 January, pp. 1-16.
[8] Vector Institute, Vector's Advanced Embedded Development Board for
8051 User Manual 2010. Hyderabad: Vector Institute Press Vector Institute.
[9] Collins A, A Low Cost Watt Hour Energy Meter Based on the ADE7755.
Application note 1999: 2-20.
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1.
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