6 introduction

WIRELESS DISTRIBUTED LOAD SHEDDIND MANAGEMENT SYSTEM

CHAPTER-1

INTRODUCTION

Load shedding is a process in which electric power is cutoff on

certain lines of power transformers when the demand approaches the system

capacity. Load shedding is particularly important in isolated systems since

there is no interconnected supply of power if the demand exceeds the power

rating of the transformers. Typically load shedding is done by supervisory

and monitoring systems such as supervisory control and data acquisition

systems known as SCADA systems which continuously monitor vital

parameters of the power system. SCADA systems usually shed the

appropriate power load keeping a well-balanced system and at the same time

maintaining reasonable customer satisfaction.

Systems located in a hot climate zone, such as the emirates of

Sharjah and Dubai of the United Arab Emirates, have many remotely-

distributed transformers throughout the coverage area. During hot days, the

peak power consumption is significantly higher than normal days. Even

though the power grid is designed to handle such peak loads, it is possible

that spurious excessive demand may cause power shutdown.

1.1.OBJECTIVE

Wireless –Distributed Load-Shedding Management System which

is designed to handle remotely distributed transformers which is located in

hot climatic zone, lacking SCADA system using GSM technique. The

Dept of EEE,MESITAM 1


proposed system is used to protect the distributed transformers and

proactively involves users in the shedding process.

1.2. SYSTEM DESIGN

The designed system called Wireless Distributed Load-Shedding

Management System consists of three main modules. The DCM, the

wireless communication module, and the CPM. The DCM is installed at the

physical location of the transformer site. It consists of a system status

monitor, that continuously records and processes current on each feeder. The

wireless communication module consists of a GPRS modem that sends SMS

messages over the GSM messages over the GSM network from the control

center to the transformer site. This module is the communication backbone

of the proposed system. The CPM processes the data, collected and fed-back

by the GPRS modem at the transformer site, and sends control signals

depending on the situations such as faults and overloads, or by special

requests from authorized employees.

1.3 MODES OF OPERATION

The system should be configured to operate in two different

modes: standard and caution modes.

In the standard mode the system sensors measure the current per

feeder, oil temperature and the location temperature of the transformer every

hour and send an end-of-day SMS (type-C) to the control center server.

Type-C SMS contains transformer number, average current readings on all



feeders, and oil temperature readings of the transformer. The purpose of

these end-of-day SMS messages is to increase the reliability of data

collection and to frequently update the database. Physical fault at the

transformers site, a type-B SMS message is sent to the server.

WDL-SMS will operate in caution mode if current loads on any

of the transformer feeders exceed a specified preset values. A type-A

overload SMS message will be sent to the server. The control center server

then searches for respective consumers on that particular feeder inside its

database. The server initiates “Overload” SMS messages to these consumers,

asking them to reduce their power consumption. If the load is not reduced

within a certain period of time called grace period, the control center asks

the DCM at the transformers site to disconnect one or more feeders by

sending Disconnect SMS. The system will also operated in caution mode if

the oil and/or location temperature of the transformer exceed some preset

threshold values.

1.4 COMMUNICATION PROTOCOL

As the systems modules need to interact with each others during

system operation, several communications messages are used between

modules. These messages include microcontroller-to-server, server-to-

microcontroller, and server-to-consumer messages.

1.4.1 Microcontroller-to-server Messages



Microcontroller messages are mainly used in reporting data from

the DCM module to the server of the CPM module. Three types of messages

are used :

Alarm Message

Update Message

Fault Message

Send-on-Request Message

1.4.2 Server-to-microcontroller Messages

The server communicates with the microcontroller using three

different types of message: Request, Disconnect and Connect.

Request Message:

Whenever the current reading of the transformer parameters are

required by the utility site, a message is sent to the microcontroller

Disconnect Message: This message is sent to the microcontroller if the feeders are to

be disconnected by the company.

Connect Message:

This message is sent to the microcontroller if the feeders are to

be reconnected by the company.

1.4.3 Server-to-consumer Messages

In the event of excess power consumption, the consumer

might receive the following alert message “Please reduce your power

consumption or else you might suffer power loss. Thank you”.This message

consists of 65 ASCII characters totaling 455 bits per SMS message per

alerted customer.



CHAPTER-2

BLOCK DIAGRAM DESCRIPTION



Fig2.1: Block diagram

2.1. INTRODUCTION

The block diagram comprises of ATMEGA 328, GSM modem,

Relay, Interfacing Device(RS 232 Serial port) and Temperature Sensor.

Each device in each block has its own duties and functions.

2.2. ATMEGA 328

Micro controller (ATMEGA 328) is the main heart of our system. It

operates in 5v supply. All the devices is being connected with

microcontroller including Temperature sensor, Relay, GSM modem .The

operating conditions were programmed and been loaded in the

microcontroller. It will work according to the operating conditions. The

relay will be turn on/off according to the instructions that are given by the

microcontroller. The GSM modem is connected through interfacing devices

known as RS 232 serial port.

2.3. GSM MODEM

The GSM modem is being interfaced with microcontroller

through RS 232 serial port. It will send early warning messages to the

customer for reducing the power consumption. A GSM modem can be a



dedicated modem device with a serial, USB or Bluetooth connection, or it

may be a mobile phone that provides GSM modem capabilities. A GSM

modem exposes an interface that allows applications such as Now SMS to

send and receive messages over the modem interface.

2.4. TEMPERATURE SENSOR (LM35)

Temperature sensor will sense atmospheric temperature. The

temperature limit can be set in the program itself. Here LM35 is used as the

Temperature sensor. If the temperature exceed the fixed value it will send

message to the Electricity Board.

2.5. RELAY

Relay is an electrical switch that opens and closes under the

control of another electrical circuit. In the original form, the switch is

operated as an electromagnet to open or close one or more sets of contacts.

A Relay is able to control an output circuit of higher power than the input

circuit, it can be considered to be, in a broad sense, a form of an electrical

amplifier. The relay will turned off if any disturbance occur in the system.

2.6. RS 232 INTERFACE

It is a standard serial interfacing device used for interfacing PIC

and GSM modem. It will work with the voltages of -15V to +15V for high

and low. The voltage for logic 1 ranges from -3V to -12V and for logic 0 it



ranges from +3V to +12V.Modern low-power logic operates in the range of

0V….+3.3V or even lower.

CHAPTER-3

HARDWARE DESCRIPTIONS

The main hardware equipments which were employed in our

project are Micro controller (ATMEGA 328), LCD Display, GSM modem,

Current Transformers (CT’s), Relays, Feeders, Loads, Temperature Sensor.

Each of them is been briefly explained one by one as follow:

3.1.ATMEGA 328

Fig.2 .ATMEGA 328

Micro controller (ATMEGA 328) is the main heart of our system. It

operates in 5v supply. All the devices is being connected with

microcontroller including Temperature sensor, Relay, GSM modem .The



operating conditions were programmed and been loaded in the

microcontroller. It will work according to the operating conditions. The

relay will be turn on/off according to the instructions that are given by the

microcontroller. The GSM modem is connected through interfacing devices

known as RS 232 serial port.

Fig. PINOUT DIAGRAM

3.2.PIN DESCRIPTIONS

Write something here regarding the pin details below & start all

paragraph with a space

3.2.1.VCC

Digital supply voltage.

3.2.2 GND

Ground.



3.2.3 Port B (PB7:0) XTAL1/XTAL2/TOSC1/TOSC2

…………Port B is an 8-bit bi-directional I/O port with internal pull-up

resistors (selected for each bit). The Port B output buffers have symmetrical

drive characteristics with both high sink and source capability. As inputs,

Port B pins that are externally pulled low will source current if the pull-up

resistors are activated. The Port B pins are tri-stated when a reset condition

becomes active, even if the clock is not running.

Depending on the clock selection fuse settings, PB6 can be used as input to

the inverting Oscillator amplifier and input to the internal clock operating

circuit. Depending on the clock selection fuse settings, PB7 can be used as

output from the inverting Oscillator amplifier. If the Internal Calibrated RC

Oscillator is used as chip clock source, PB7...6 is used as TOSC2...1 input

for the Asynchronous Timer/Counter2 if the AS2 bit in ASSR is set.

3.2.4 Port C (PC5:0)

……….Port C is a 7-bit bi-directional I/O port with internal pull-up resistors

(selected for each bit). The PC5...0 output buffers have symmetrical drive

characteristics with both high sink and source capability. As inputs, Port C

pins that are externally pulled low will source current if the pull-up resistors

are activated. The Port C pins are tri-stated when a reset condition becomes

active, even if the clock is not running.

3.2.5 PC6/RESET

If the RSTDISBL Fuse is programmed, PC6 is used as an I/O pin. Note that

the electrical characteristics of PC6 differ from those of the other pins of

Port C. If the RSTDISBL Fuse is unprogrammed, PC6 is used as a Reset

input. A low level on this pin for longer than the minimum pulse length will

generate a Reset, even if the clock is not running.



3.2.6 Port D (PD7:0)

Port D is an 8-bit bi-directional I/O port with internal pull-up resistors

(selected for each bit). The Port D output buffers have symmetrical drive

characteristics with both high sink and source capability. As inputs, Port D

pins that are externally pulled low will source current if the pull-up resistors

are activated. The Port D pins are tri-stated when a reset condition becomes

active, even if the clock is not running.

3.2.7 AVCC

AVCC is the supply voltage pin for the A/D Converter, PC3:0, and ADC7:6.

It should be externally connected to VCC, even if the ADC is not used. If

the ADC is used, it should be connected to VCC through a low-pass filter.

Note thatPC6...4 use digital supply voltage, VCC.

3.3. LCD MODULE

Fig.3.LCD Module

Don’t under line



A liquid crystal display (LCD) is a thin, flat electronic visual

display that uses the light modulating properties of liquid crystals (LCs).

LCs does not emit light directly.

They are used in a wide range of applications, including

computer monitors, television, instrument panels, aircraft cockpit displays,

signage, etc. They are common in consumer devices such as video players,

gaming devices, clocks, watches, calculators, and telephones. LCDs have

displaced cathode ray tube (CRT) displays in most applications. They are

usually more compact, lightweight, portable, less expensive, more reliable,

and easier on the eyes] They are available in a wider range of screen sizes

than CRT and plasma displays, and since they do not use phosphors, they

cannot suffer image burn-in.

LCDs are more energy efficient and offer safer disposal than

CRTs. Its low electrical power consumption enables it to be used in battery-

powered electronic equipment. It is an electronically-modulated optical

device made up of any number of pixels filled with liquid crystals and

arrayed in front of a light source (backlight) or reflector to produce images

in colour or monochrome.

3.4.GSM MODEM


http://en.wikipedia.org/wiki/Monochrome

http://en.wikipedia.org/wiki/Reflector_(photography)

http://en.wikipedia.org/wiki/Backlight

http://en.wikipedia.org/wiki/Light#Light_sources

http://en.wikipedia.org/wiki/Liquid_crystal

http://en.wikipedia.org/wiki/Pixel

http://en.wikipedia.org/wiki/Electro-optic_modulator


http://en.wikipedia.org/wiki/Electronics

http://en.wikipedia.org/wiki/Battery_(electricity)

http://en.wikipedia.org/wiki/Plasma_display

http://en.wikipedia.org/wiki/Cathode_ray_tube

http://en.wikipedia.org/wiki/Telephone

http://en.wikipedia.org/wiki/Calculator

http://en.wikipedia.org/wiki/Clock

http://en.wikipedia.org/wiki/Signage

http://en.wikipedia.org/wiki/Flight_instruments

http://en.wikipedia.org/wiki/Television

http://en.wikipedia.org/wiki/Computer_monitor

http://en.wikipedia.org/wiki/Liquid_Crystals

http://en.wikipedia.org/wiki/Electronic_visual_display

http://en.wikipedia.org/wiki/Electronic_visual_display


Fig.4.GSM Modem

A GSM modem is a specialized modem which accepts SIM

card and operates over a subscription to a mobile operator, just like a mobile

phone. A GSM modem has a serial connection. A GSM modem exposes an

interface that allows applications such as to send and receive messages over

the modem interface. A GSM modem is a wireless modem that works with

wireless network. Computers use AT commands (Attention commands) to

control modems. The number of SMS that can be processed by a GSM per

minute is about 6-10. A GSM modem is a wireless modem that works with a

GSM wireless network. A wireless modem behaves like a dial-up modem.

The main difference between them is that a dial-up modem sends and

receives data through a fixed telephone line while a wireless modem sends

and receives data through radio waves.

GSM modems can be a quick and efficient way to get started

with SMS, because a special subscription to an SMS service provider is not

required. The mobile operator charges for this message sending and

receiving as if it was performed directly on a mobile phone.

3.4.1. GSM MODEM FEATURES



Quad Band GSM/GPRS

850/900/1800/1900Mhz

GPRS multi-slot class 10/8

GPRS Mobile station class B

Compliant to GSM Phase 2/2+

Class 4 (2W@850/900Mhz)

Class 1(1W@1800/1900Mhz)

Control via AT commands (GSM 07.07, 07.05 and enhanced AT

commands)

3.4.2. INTERFACES

RS-232 through D-TYPE 9 pin connector, Serial port baud rate

adjustable 1200 to115200 bps (9600 default)

Stereo connector for MIC & SPK

Power supply through DC socket

SMA antenna connector

Push switch type SIM holder

LED status of GSM / GPRS module

3.3.3. AT COMMANDS

Communication with the GSM modem is by using AT

commands. To perform these tasks, a GSM modem must support an

"extended AT command set" for sending/receiving SMS messages.



Commands for Reading and Sending SMS is as follows

1. Set SMS mode

Command : AT+CMGF=1

2. Send SMS

Command : AT+CMGS=<”number”><Crriagereturn>(new line)

(>)<matter> <ctrl+z>

3. Read SMS

Command : AT+CMGR=<location>

3.4.4. SIM305/SIM345 (GSM MODEM)

The SIM305/345 is a complete Dual-band/Quad-band

GSM/GPRS solution in a compact plug-in module. Featuring an industry-

standard interface, the SIM305/345 delivers GSM/GPRS

50/900/1800/1900MHz performance for Voice, SMS, Data, and Fax in a

small form factor and with low power consumption.

The leading features of SIM305/345 make it ideal for M2M applications,

such as AMR, POS, Security, AVL etc.

3.4.4.1. General features

Dual-Band GSM/GPRS 900/1800MHz or Quad-Band GSM/GPRS

850/900/1800/1900MHz

GPRS multi-slot class 10

GPRS mobile station class B



Compliant to GSM phase 2/2+

Class 4 (2 W @ 850/900MHz)

Class 1 (1 W @ 1800/1900MHz)

Dimension: 58mm x 32mmx 3.9 mm

Weight: <12g

SIM application toolkit

Supply voltage range 3.4 ... 4.5 V

Low power consumption

Normal operation temperature: -30°C to +80°C

Restricted operation temperature: -40°C to -30°C and +80°C to +85°C

Storage temperature: -45°C to +90°C

3.4.4.2. Specifications for SMS via GSM / GPRS

Point-to-point MO and MT

SMS cell broadcast

Text and PDU mode

3.5. CURRENT TRANSFORMER



Fig.5.Different Types of Current Transformers

Here two Current Transformers are used to measure the

current across feeders. It will out the corresponding voltage values by the

principle of Electromagnetic Induction. The phase of each feeders were

passed through the core of CT’s. It is rated to be 5A. A bridge circuit is

necessary for connecting the Current Transformers.

It is not possible to use line current directly for

measurement and relaying purpose due to its high value and insulation

problem. CURRENT TRANSFORMER which is widely known as 'CT ' is a

piece of electrical equipment which converts line current (primary current)

in to small standard current values which are suitable for the devices to

which it is connected e.g. measuring instruments, meters, protection relays.

3.5.1. BASIC FUNCTIONS OF CT’s



To reduce line current to a value which is suitable for standard

measuring instruments, relays etc.

To isolate the measuring instruments, meters, relays etc. from line

voltage of an installation.

To protect measuring instruments against short circuit currents.

To sense abnormalities in current and give current signals to

protective relays to isolate the defective system

Ring type (or rectangular type) CTs are normally preferred

over other types of CTs. because they are simple in construction,

mechanically stronger and cheaper. In a ring type/bar primary type CTs the

working ampere-turns are determined by the primary current and therefore

necessarily, the accuracy that can be offered with these CTs becomes

progressively inferior as the rated primary current decreases.'-If higher

accuracy and burdens are required for CTs of low primary current wound

types CTs are used.

3.6. MAX 232 LEVEL CONVERTERS

.

Fig.6. MAX 232 pin Fig.7.MAX 232 Interface


http://en.wikibooks.org/wiki/File:Max232.jpg


For interfacing PIC and GSM modem Serial RS-232

communication is used. It works with voltages 15V to +15V for high and

low. On the other hand, TTL logic operates between 0V and +5V . Modern

low power consumption logic operates in the range of 0V and +3.3V or even

lower.

Thus the RS-232 signal levels are far too high TTL electronics,

and the negative RS-232 voltage for high can’t be handled at all by computer

logic. To receive serial data from an RS-232 interface the voltage has to be

reduced also the low and high voltage level has to be inverted.

Table-1

This module is primary of interest for people building their own

electronics with an RS-232 interface. Serial RS-232 communication works

with voltages (-15V ... -3V for high ) and +3V ... +15V for low) which are

not compatible with normal computer logic voltages. On the other hand,

classic TTL computer logic operates between 0V ... +5V (roughly 0V ...

+0.8V for low, +2V ... +5V for high). Modern low-power logic operates in

the range of 0V ... +3.3V or even lower.

So, the maximum RS-232 signal levels are far too high for

computer logic electronics, and the negative RS-232 voltage for high can't


RS-232 TTL Logic

-15V … -3V +2V … +5V High

+3V … +15V 0V … +0.8V Low

http://sodoityourself.com/max232-serial-level-converter/


be grokked at all by computer logic. Therefore, to receive serial data from

an RS-232 interface the voltage has to be reduced, and the low and high

voltage level inverted. In the other direction (sending data from some logic

over RS-232) the low logic voltage has to be "bumped up", and a negative

voltage has to be generated, too.

RS-232 TTL Logic

-----------------------------------------------

-15V ... -3V <-> +2V ... +5V <-> high

+3V ... +15V <-> 0V ... +0.8V <-> low

All this can be done with conventional analog electronics,

e.g. a particular power supply and a couple of transistors or the once

popular 1488 (transmitter) and 1489 (receiver) ICs. However, since more

than a decade it has become standard in amateur electronics to do the

necessary signal level conversion with an integrated circuit (IC) from the

MAX232 family (typically a MAX232A or some clone). In fact, it is hard

to find some RS-232 circuitry in amateur electronics without a MAX232A

or some clone.

The MAX232 from Maxim was the first IC which in one

package contains the necessary drivers (two) and receivers (also two), to

adapt the RS-232 signal voltage levels to TTL logic. It became popular,

because it just needs one voltage (+5V) and generates the necessary RS-

232 voltage levels (approx. -10V and +10V) internally. This greatly

simplified the design of circuitry. Circuitry designers no longer need to

design and build a power supply with three voltages (e.g. -12V, +5V, and


http://www.maxim-ic.com/


+12V), but could just provide one +5V power supply, e.g. with the help of

a simple 78x05 voltage converter.

3.7. RELAY

Fig.8.Relay

Here three relays are used, two for two feeders and one for

Temperature sensor. A relay is a simple electromechanical switch made up

of an electromagnet and a set of contacts. Relays are found hidden in all

sorts of devices. In fact, some of the first computers ever built used relays to

implement Boolean gates .

A simple electromagnetic relay consists of a coil of wire

surrounding a soft iron core , an iron yoke which provides a low reluctance

path for magnetic flux, a movable iron armature, and one or more sets of

contacts (there are two in the relay pictured). When an electric current is

passed through the coil it generates a magnetic field that attracts the

armature and the consequent movement of the movable contact(s) either

makes or breaks (depending upon construction) a connection with a fixed

contact. If the set of contacts was closed when the relay was de-energized,


http://en.wikipedia.org/wiki/Magnetic_field

http://en.wikipedia.org/wiki/Electric_current

http://en.wikipedia.org/wiki/Armature_(electrical_engineering)

http://en.wikipedia.org/wiki/Magnetic_reluctance

http://en.wikipedia.org/wiki/Magnetic_core

http://en.wikipedia.org/wiki/Coil

http://electronics.howstuffworks.com/boolean.htm

http://electronics.howstuffworks.com/electromagnet.htm

http://www.google.co.in/imgres?imgurl=http://1.bp.blogspot.com/_c8EartLqdVs/TNQ_DCmZeKI/AAAAAAAAAms/eXyj0Y6J1hE/s1600/Relay.jpg&imgrefurl=http://mechatrotutor.blogspot.com/2010/11/relay-driver-overview.html&usg=__VfWXLcKHvjABHC2AQaS9geeNiI0=&h=640&w=640&sz=121&hl=en&start=8&sig2=1NBmgQiOjuoRZrV_zMOPrQ&zoom=1&itbs=1&tbnid=5EGaBMA5wCp_VM:&tbnh=137&tbnw=137&prev=/images?q=relay&hl=en&gbv=2&tbs=isch:1&ei=B3GDTZ79GJHRrQeAvcjCCA


then the movement opens the contacts and breaks the connection, and vice

versa if the contacts were open.

Relays are used to and for:

Control a high-voltage circuit with a low-voltage signal, as in some

types of modems or audio amplifiers,

Control a high-current circuit with a low-current signal, as in the

starter solenoid of an automobile,

Detect and isolate faults on transmission and distribution lines by

opening and closing circuit breakers (protection relays).

3.8. LOADS

Fig.9. Electrical Appliances Fig.10. 60V bulb

The various loads were connected at the feeder side. When the

consumption of power exceed the feeder is overloaded .Now a day’s various

electrical appliances like bulb, mixy , motor consuming huge amount of

power in residual areas .In industries huge power consumption devices like

motors, transformers require large power for working .For working of the

hardware one 40V bulb and one 60V bulb is used.


http://en.wikipedia.org/wiki/Circuit_breakers

http://en.wikipedia.org/wiki/Automobile

http://en.wikipedia.org/wiki/Solenoid

http://en.wikipedia.org/wiki/Starter_motor

http://en.wikipedia.org/wiki/Electric_current

http://en.wikipedia.org/wiki/Modems

http://www.google.co.in/imgres?imgurl=http://compareindia.in.com/media/images/2008/feb/img_41621_home_appliances.jpg&imgrefurl=http://www.inetgiant.in/home/home-appliances/13&usg=__jPklqUNg27UpbLeLrUoR62k3CPw=&h=880&w=880&sz=66&hl=en&start=52&sig2=0Dv6LMSXwSitc2CpKRKaJQ&zoom=1&itbs=1&tbnid=MC7FYO2eecFgEM:&tbnh=146&tbnw=146&prev=/images?q=electrical+appliances&start=36&hl=en&sa=N&gbv=2&ndsp=18&tbs=isch:1&ei=2XSDTaukH4zNrQfhsvy6CA


According to the type of load using consumption of power

varies. For starting of the certain equipment require large power. During hot

days, the peak power consumption is significantly higher than normal loads.

Even though the power grid is designed to handle such peak loads, it is

possible that spurious excessive demand may cause power shutdown.

Together with ambient temperature, this could be leveraged to give enough

lead time to take the necessary measures to avoid excess load and potentially

massive power outages.

Use SAME FONT & FONT SIZE FOR ALL DOC

& Align all paragraph like this below

According to the type of load using consumption of power

varies. For starting of the certain equipment require large power. During hot



days, the peak power consumption is significantly higher than normal loads.

Even though the power grid is designed to handle such peak loads, it is

possible that spurious excessive demand may cause power shutdown.

Together with ambient temperature, this could be leveraged to give enough

lead time to take the necessary measures to avoid excess load and potentially

massive power outages.

CHAPTER-4

CIRCUIT EXPLANATIONS

In circuit explanation we are explaining about the various

inter connections of each device. Each pin in each device has its own

functions.



4.1. POWER SUPPLY

Fig11:Power supply circuit

The above figure shows the power supply circuit. Input is given

through DC adaptor. Diode IN4007 is to avoid the polarity inversion when

plugging. LED is for displaying the status. Capacitive filters are used to

eliminate ripples. 1000uF capacitor is electrolytic and 0.1uF is disc

capacitor. The capacitor filter should be rated at a minimum of 1000uF for

each amp of current drawn and at least twice the input voltage. The 0.1uF

capacitor eliminates any high frequency pulses that could otherwise interfere

with the operation of the regulator. Voltage regulators are very robust. They

can withstand over-current draw due to short circuits and also over-heating.

In both cases the regulator will shut down before damage occurs. The only

way to destroy a regulator is to apply reverse voltage to its input.

A IN4004, 1 amp power diode is connected in series with the

power supply. If the supply is connected the wrong way around, the

regulator will be protected from damage.


R 21 . 2 K C 4

1 0 3

C 11 0 0 u F / 1 6 V

D 3

L E D

J 1

C O N 3

123

0

+5 V C CU 1L M 7 8 0 5 C / TO 2 2 0

1 3

2

I N O U T

GN

D

D 2

1 N 4 0 0 7 C 3

1000

uF/2

5V

C 2

1 0 4

+1 2 v


The LM78XX series of three terminal regulators is available

with several fixed output voltages making them useful in a wide range of

applications. One of these is local on card regulation, eliminating the

distribution problems associated with single point regulation. The voltages

available allow these regulators to be used in logic systems, instrumentation,

HiFi, and other solid state electronic equipment. Although designed

primarily as fixed voltage regulators these devices can be used with external

components to obtain adjustable voltages and currents. The LM78XX series

is available in an aluminum TO-3 package which will allow over 1.0A load

current if adequate heat sinking is provided. Current limiting is included to

limit the peak output current to a safe value. Safe area protection for the

output transistor is provided to limit internal power dissipation.

If internal power dissipation becomes too high for the heat

sinking provided, the thermal shutdown circuit takes over preventing the IC

from overheating. Considerable effort was expanded to make the LM78XX

series of regulators easy to use and minimize the number of external

components. It is not necessary to bypass the output, although this does

improve transient response. Input bypassing is needed only if the regulator is

located far from the filter capacitor of the power supply

4.2. LCD DISPLAY

The LCD module is a parallel interface sixteen pin module. The

first three pins of LCD module are used for contrast adjusting. Here the first

pin is connected to ground, second to the voltage supply and third to the

variable resistor. The pins, seven to fourteen are data lines (D0 to D7). In



this particular circuit the data lines D4 to D7 are used because the LCD

driver available is 4 line data bus. 15th pin is connected to the 5 volt supply.

Pin 4, 5, 6 are control pins, R/W, RS and enable respectively.

16th pin is connected to the ground through a transistor. The voltage from

pic16f877a turn on the transistor and it in turn turns on the LCD

backlight .Resistor R9 controls the voltage supplied to the transistor.

4.2.1. PINOUT

LCD modules may have a parallel or serial interface. The module

discussed here has a 14-pin parallel interface. The pin out for this module is

shown below.

4.2.1.1. Enable (E) :

This line allows access to the display through R/W and RS

lines. When this line is low, the LCD is disabled and ignores signals from

R/W and RS. When (E) line is high, the LCD checks the state of the two

control lines and responds accordingly.



Table-2

4.2.1.2. Read/Write (R/W):

This line determines the direction of data between the LCD and

microcontroller. When it is low, data is written to the LCD. When it is high,

data is read from the LCD.


SL.NO. SYMBOL FUNCTION

1 Vss Ground

2 Vcc +5V

3 VEE Contrast

4 RS H=Data, L=Instruction

5 R/W H=Read, L=Write

6 E Latch, HL

7 DB0 LSB

8 DB1

9 DB2

10 DB3

11 DB4

12 DB5

13 DB6

14 DB7 MSB


4.2.1.3. Register select (RS) :

With the help of this line, the LCD interprets the type of data on

data lines. When it is low, an instruction is being written to the LCD. When

it is high, a character is being written to the LCD.

4.2.1.4. Contrast:

A variable voltage applied to this pin controls the contrast. Use

a potentiometer and adjust until you see the background.

4.2.1.5. DB0-DB7:

Apply the data or commands to these pins.

LCDs are more energy efficient and offer safer disposal than

CRTs. Its low electrical power consumption enables it to be used in battery-

powered electronic equipment. It is an electronically-modulated optical

device made up of any number of pixels filled with liquid crystals and

arrayed in front of a light source (backlight) or reflector to produce images

in colour or monochrome. The earliest discovery leading to the development

of LCD technology, the discovery of liquid crystals, dates from 1888.By

2008, worldwide sales of televisions with LCD screens had surpassed the

sale of CRT units


http://en.wikipedia.org/wiki/Monochrome

http://en.wikipedia.org/wiki/Reflector_(photography)

http://en.wikipedia.org/wiki/Backlight

http://en.wikipedia.org/wiki/Light#Light_sources

http://en.wikipedia.org/wiki/Liquid_crystal

http://en.wikipedia.org/wiki/Pixel



http://en.wikipedia.org/wiki/Electronics

http://en.wikipedia.org/wiki/Battery_(electricity)


4.3. MAX232

It consists of 16 pins.pin 1&3connected by a capacitor. Pin 4&5

connected through a capacitor. Pin 11 &12 connected to a 24&25 pin of PIC.

Pin 14&13 are connected to 2&3 pin of RS232. Pin 6 of MAX232and pin 5

of RS232 to GND through a capacitor C7.Pin 2 is connected to supply

through a capacitor

. +-----v-----+C1+-|1 16|- VccV+ -|2 15|- GNDC1--|3 14|- T1outC2+-|4 13|- R1inC2--|5 12|- R1outV- -|6 11|- T1inT2o-|7 10|- T2inR2i-|8 9|- R2out +-------+

Fig.13.Pin Layout of MAX 232(A) DIP Package

The MAX232(A) has two receivers (converts from RS-232 to TTL

voltage levels) and two drivers (converts from TTL logic to RS-232 voltage

levels). This means only two of the RS-232 signals can be converted in each

direction. The old MC1488/1498 combo provided four drivers and receivers.

There are not enough drivers/receivers in the MAX232 to also

connect the DTR, DSR, and DCD signals. Usually these signals can be

omitted when e.g. communicating with a PC's serial interface. If the DTE



really requires these signals either a second MAX232 is needed, or some

other IC from the MAX232 family can be used (if it can be found in

consumer electronic shops at all). An alternative for DTR/DSR is also given

below. Maxim's data sheet explains the MAX232 family in great detail,

including the pin configuration and how to connect such an IC to external

circuitry. This information can be used as-is in own design to get a working

RS-232 interface. Maxim's data just misses one critical piece of information:

How exactly to connect the RS-232 signals to the IC one.

4.4. RS232 SERIAL PORT

It consists of 6 pins, out of this pin 3&2 are connected to 13&14

of MAX232. Pin 5 is connected to gnd.

MAX232 to RS232 DB9 Connection as a DCE

MAX232 Pin No. MAX232 Pin Name Signal Voltage DB9 Pin

7 T2out RTS RS-232 8

8 R2in CTS RS-232 7

9 R2out CTS TTL n/a

10 T2in RTS TTL n/a

11 T1in TX TTL n/a

12 R1out RX TTL n/a

13 R1in TX RS-232 3

14 T1out RX RS-232 2


http://pdfserv.maxim-ic.com/en/ds/MAX220-MAX249.pdf


15 GND GND 0 5

Table-3

4.5. FEEDERS

3 relays were used, out of this two for 2 feeders and one for

transformer. Relay has 3 pins N0, NC,C. if the switch is closed position then

connected to NC. Three resistors were connected across 3 relays. 3 resistor

pin connections were connected to 16,17,18 pin of PIC. A 12v supply is

taken from power supply circuit.

4.6.CIRCUIT FABRICATION AND SOLDERING DETAIL

4.6.1.Pcb fabrication

Printed Circuit Broad (PCB) is a mechanical assembly

consisting of layers of fiberglass sheet laminated with etched copper

patterns. It is used to mount electronic parts in a rigid manner suitable for

packaging.

The type of integrated circuit components used in the

fabrication process has an important role in the design of PCB. The

conductor width, spacing between the signal conductors etc, are calculated

to give optimum wave impedance of the conductor's lines. Optimum wave

impedance gives minimum delay or rising and trailing edge of the pulse in

digital circuit.



4.6.2.Soldering

Soldering is an important skill for electrical technician. Good

soldering is important for proper operation of equipment.Solder is an alloy

of tin and lead. The solder that is most used is60/40 solder. This means that

it is made from 60% tin and 40% lead. Solder melts at a temperature of

about 400 degree Fahrenheit. For solder to adhere to join, the parts must to

enough to melt the solder. Rosin flux is contained inside the solder. It is

called rosin-core solder. A good mechanical joint must be made when

soldering. Heat is then applied until the material rare hot. When they are hot,

solder is applied to the joint. The heat of the metal parts is used to melt the

solder. Only a small amount of heat should be used sparingly. The joint

should appear smooth and thin. If it does not, it could be a "cold" solder

joint. This is called a “cold joint". Care should be taken not to damage PCB

when soldering parts on to them. Small, low wattage irons should be used

with PCB and semiconductor devices



Fig.14.Board connection

Change with a new figure



Fig.15.Circuit diagram of hardware



CHAPTER-5SOFTWARE DEVELOPMENT TOOLS

Write about the software and how did you burn the

program to MC

Program codes are generally shown in appendix 1 or 2

Clarify this the project coordinator 5.1. PROGRAM FOR MICROCONTROLLER:

#include<16f877a.h>

#include"pic1.h"

#include"lcd1.h"

#define transformer rc1

#define fr1 rc2

#define fr2 rc3

int count,p,pflg=0,t;

int fr1flg=1,fr2flg=1,trflg=1,f1,f2,afl;

char kseb[]="9486669772";

void sms_send(void)

{

putchar(26);

delay_ms(200);

}



void sms_start_kseb(char*ch)

{

printf("AT+CMGF=1\r");

printf("AT+CMGS=");

printf("\"+91");

printf("%s\"\r",ch);

}

#int_RTCC

RTCC_isr()

{

count++;

if (count>100000)

{

count=0;

fr1

flg=1,fr2flg=1,trflg=1;

fr1=fr2=transformer=afl=1;

set_timer0(0x00);

}

}

float feeder1()

{

set_adc_channel(0);

delay_us(20);

if(fr1flg&&trflg) // Checking status of F1



return(read_adc());

}

float feeder2()

{

set_adc_channel(1);

delay_us(20);

if(fr2flg&&trflg) // Checking status of F2

return(read_adc());

}

float temp()

{

set_adc_channel(2);

delay_us(20);

if(trflg)

return(read_adc()*5.0/255*100);

}

void grace_period()

{

pflg=0;

while(p<18)

{

p=p+1;

delay_ms(2000); //20000

go(64);



print(p);

delay_ms(300);

}

pflg=1;

clrscr();

}

void sms_start_c(char*ch)

{

printf("AT+CMGF=1\r");

printf("AT+CMGS=");

printf("\"+91");

printf("%s\"\r",ch);

printf("Please reduce your power consumption\r");

printf(" or else you might suffer Power Loss!\r");

printf("Thank You....");

sms_send();

}

void main()

{

int k,i,f1,f2,f1flg;

char msg[ ]="WDL SMS";

char F1C1[ ]="9791668561";

char F1C2[ ]="9655166177";

char F1C3[ ]="9787239229";

char F2C1[ ]="7708311801";



char F2C2[ ]="9487449774";

char F2C3[ ]="9496369807";

char trsf[ ]="Transformer is Off";

trisd=0x00;

trisc1=trisc2=trisc3=0;

enable_interrupts(global);

enable_interrupts(INT_RTCC);

setup_adc_ports(ALL_ANALOG);

setup_adc(ADC_CLOCK_INTERNAL);

setup_timer_0 (RTCC_INTERNAL|RTCC_DIV_256);

set_timer0(0x00);

TRISB=0X00;

fr1=fr2=transformer=1;

lcdinit();

go(4);

prints(msg);

delay_ms(800);

clrscr();

afl=0;

f1flg=1;

while(1)

{

f1=feeder1();

f2=feeder2();

if(f2>200)



f1flg=0;

else

f1flg=1;

pflg=0;

go(0);

printc("F1=");

go(3);

//clrscr();

if(!f1flg)

f1=0;

print(f1);

delay_ms(700);

go(8);

printc("F2=");

go(11);

//clrscr();

print(f2);

delay_ms(700);

t=temp();

go(67);

printc("Temp=");

go(73);

print(t);

delay_ms(200)

if(t>45)

{



sms_start_kseb(kseb);

printf("High Temp : TRANSOFRMER IS OFF\r");

sms_send();

transformer=fr1=fr2=0;

trflg=0;

go(64);

prints(trsf);

delay_ms(500);

clrscr();

}

if(f1>140)

delay_ms(200);

if(f1>140)

{

if(!pflg)

{

clrscr();

go(68);

printc("F1 HIGH");

delay_ms(200);

sms_start_c(F1C1);

sms_send();

sms_start_c(F1C2);

sms_send();

sms_start_c(F1C3);



sms_send();

}

p=0;

grace_period();

}

if(f2>230)

{

delay_ms(200);

if(f2>230)

{

if(!pflg)

{

clrscr();

go(68);

printc("F2 HIGH");

delay_ms(200);

sms_start_c(F2C1);

sms_send();

sms_start_c(F2C2);

sms_send();

sms_start_c(F2C3);

sms_send();

}

p=0;

grace_period();

}



}

if(pflg)

{

f1=feeder1();

if(f1>140)

{

fr1=0;

fr1flg=0; // If Feeder1 off

pflg=0;


printf("Feeder1 Is OFF");

sms_send();

clrscr();

printc("Feeder1 Is OFF");

delay_ms(500);

clrscr();

}

}

if(pflg)

{

f2=feeder2();

if(f2>230)

{

fr2=0;

fr2flg=0; //If Feeder2 off



pflg=0;


printf("Feeder2 Is OFF");

sms_send();

clrscr();

printc("Feeder2 Is OFF");

delay_ms(500);

clrscr();

}

}

}



CHAPTER-6

CONCLUSION

Wireless Distributed Load Shedding Management System

(WDL-SMS) was implemented and tested. It was verified to operate

successfully under standard and caution modes. GSM network was

successfully used in remote monitoring and control .Recent advances in the

technology can be leveraged in order to make WDL-SMS more stable and

feature-rich.

NOT NEEDED

Here we are glad to present the project titled as “WIRELESS

DISTRIBUTED LOAD SHEDDING MANAGEMENT SYSTEM’’. We

have introduced our project in small scale manner to expose large ideas in

transformer side.

We are sure that this project is very useful and needful one to all.



CHAPTER-7

FUTURE SCOPE

In the future the system could call the mobile technicians

and use a pre-recorded voice to tell the fault rather than sending SMS .It can

also E-mail a summary of readings of all transformers to employees on a

regular basis. It can monitor, record and update transformer parameters more

frequently. In future an Artifical Neural Network(ANN)can be used in

forecasting, or predicting overloads and abnormal conditions.ANN can be

configured to recognize specific pattern or data classification, through a

learning process.



DON’T PUT CHAPER NO FOR APPENDIX , Just write it as APPENDIX I or APPENDIX II

CHAPTER-8

APPENDICES

8.1.USART

The Universal Synchronous Asynchronous Receiver Transmitter

module is one of the two serial I/O modules

The USART can be configured

as a full duplex asynchronous system

or it can be configured as a half duplex synchronous

8.1.1.USART MODULE The USART can be configured in these modes:

Asynchronous (full duplex)

Synchronous - Master (half duplex)

Synchronous - Slave (half duplex)



Bit SPEN (RCSTA<7>) and bits TRISC<7:6> have to be set to

configure pins RC6/TX/CK and RC7/RX/DT as the USART

The USART module also has a multi-processor communication

capability using 9-bit address detection.

8.1.2.FULL DUPLEX ASYNCHRONOUS OPERATION

The most common use of the USART in asynchronous mode is to

communicate to a PC serial port using the RS-232 protocol.

The UART can both transmit and receive

Full duplex operation - Both transmission and reception

can occur at the same time

The USART Asynchronous module consists of

Sampling Circuit

Asynchronous Transmitter

Asynchronous Receiver

8.1.3.BAUD RATE FORMULA

Formulas for baud rate

Baud rate = Fosc/(16(SPBRG+1)), BRGH=1

Baud rate = Fosc/(64(SPBRG+1)), BRGH=0

Formulas for SPBRG

SPBRG = (Fosc/(16 x Baud rate)) - 1, BRGH=1

SPBRG = (Fosc/(64 x Baud rate)) - 1, BRGH=0



8.2.MC78XX/LM78XX/MC78XXA

3 –Terminal 1A positive voltage regulator

8.2.1.FEATURES:

Output current up to 1A

Output voltage of 5,6,8,9,10,12,15,18,24V

Thermal overload protection

Short circuit protection

Output transistor safe operating area protection



Table-5



8.3. CAD SOFT EAGLE

EAGLE (Easily Applicable Graphical Layout Editor) is a

proprietary ECAD program produced by Cad Soft in Germany (American

marketing division: Cad Soft USA). It is very commonly used by private

electronics enthusiasts, because there is a free limited version for non-profit

use and it is available in English and German. Cad Soft has released versions

for Microsoft Windows, Linux, and Mac OS X.

EAGLE contains a schematic editor, for designing circuit

diagrams and a PCB layout editor, which allows back annotation to the

schematic.

EAGLE includes a basic but functional autorouter, or

alternatively manual routing can be performed. PCBs designed in EAGLE

are accepted by a large amount of PCB fabrication houses without the need

to export. EAGLE is very popular with hobbyists because both a basic free

edition (with a lower feature set) and a low cost non-profit edition are

available.

Schematic capture or schematic entry is a step in the design

cycle of electronic design automation (EDA) at which the electronic

diagram, or electronic schematic of the designed electronic circuit is created

by a designer. This is done interactively with the help of a schematic capture

tool also known as schematic editor.


http://en.wikipedia.org/wiki/Schematic_editor

http://en.wikipedia.org/wiki/Human-computer_interaction

http://en.wikipedia.org/wiki/Electronic_circuit

http://en.wikipedia.org/wiki/Circuit_diagram

http://en.wikipedia.org/wiki/Electronic_design_automation

http://en.wikipedia.org/wiki/Printed_circuit_board



http://en.wikipedia.org/wiki/Schematic

http://en.wikipedia.org/wiki/Mac_OS_X

http://en.wikipedia.org/wiki/Linux

http://en.wikipedia.org/wiki/Microsoft_Windows

http://en.wikipedia.org/wiki/Cadsoft

http://en.wikipedia.org/wiki/Computer-aided_design


Fig.19

The circuit design is the very first step of actual design of an

electronic circuit. Typically sketches are drawn on paper, and then entered

into a computer using a schematic editor. Therefore schematic entry is said

to be a front-end operation Therefore schematic entry is said to be a front-

end operation of several others in the design flow.

Despite the complexity of modern components – huge ball grid

arrays and tiny passive components – schematic capture is easier today than

it has been for many years. CAD software is easier to use and is available in

full-featured expensive packages, very capable mid-range packages that

sometimes have free versions and completely free versions that are either

open source or directly linked to a printed circuit board fabrication company.


http://en.wikipedia.org/wiki/Printed_circuit_board

http://en.wikipedia.org/wiki/Computer-aided_design

http://en.wikipedia.org/wiki/Ball_grid_array

http://en.wikipedia.org/wiki/Ball_grid_array

http://en.wikipedia.org/wiki/Design_flow_(EDA)

http://en.wikipedia.org/wiki/Front-end



http://en.wikipedia.org/wiki/Circuit_design


In past years, schematic diagrams with largely discrete

components were fairly readable however with the newer high pin-count

parts and with the almost universal use of standard letter-sized paper,

schematics have become less so. Many times, there will be a single large

part on a page with nothing but pin reference keys to connect it to other

pages.

Readability levels can be enhanced by using buses and super

buses, related pins can be connected into a common bus and routed to other

pages. Buses don't need to be just the traditional address or data bus directly

linked pins. A bus grouping can also be used for related uses, such as all

analog input or all communications related pin functions.


http://en.wikipedia.org/wiki/Readability

http://en.wikipedia.org/wiki/Discrete_device

http://en.wikipedia.org/wiki/Discrete_device


REFERENCES

1. A.Saffarian,M.Sanaye pasand,H.Asadi,”Performance Investigation of

New combinational load shedding schemes”,joint Internatonal Conference

on Power System Technology and IEEE power India Conference,2008

2. “Architecture of PIC Micro controller ”, www.microchip.com

3. Dellon.T.Horn ‘How to test almost anything electronics’

4. F. Capitanescu , B. Otomega,H. Lefebvre ,V. Sermanson,T.Van Cutsem,

Decentralized tap changer blocking and load shedding against voltage

instability”: Prospective tests on the RTE system ,Electrical Power and

Energy Systems.

5. IEEE,”Guide for loading mineral-oil –immersed transformers,”,IEEE

std.C57.91-1995.

6. http://robosoftsystems.co.in/roboshop/index.php/electronics-components/

led-display/16x2-alphanumeric-lcd-hd44780 “ LCD Display”


http://robosoftsystems.co.in/roboshop/index.php/electronics-components/led-display/16x2-alphanumeric-lcd-hd44780

http://robosoftsystems.co.in/roboshop/index.php/electronics-components/led-display/16x2-alphanumeric-lcd-hd44780

http://www.microchip.com/


7. http://en.wikipedia.org/wiki/555_timer_IC , “Working details of 555

Timer IC”

8. J. J.Ford ,H. Bevrani ,G. Ledwich ,”Adaptive Load shedding and

regional protection” ,International Journal of electrical power and energy

systems.

9. Ubald ‘Fundamentals Of Electronics’

10.“Voltage regulator LM 7805”, http://www.national.com/search/

LM7805.html


6 introduction

Documents