This document describes a project to remotely monitor the voltage of a power station/substation using GSM. An Arduino board measures the voltage using a potential divider circuit and sends the readings via a SIM908 GSM module in SMS messages. The project prototype monitors voltage, displays it on an LCD, and sends updates every 10 minutes. Future work could expand monitoring to other parameters and use GPRS for remote access from anywhere via the internet.

1. A PROJECT ON “REMOTE MONITORING OF A POWER STATION/ SUBSTATION (VOLTAGE MONITORING) USING GSM” Submitted to: Dr. Md. Farhad Hossain Assistant Professor, Dept. of EEE,BUET Submitted by: Abdullah Al Arafat (1006135) Tuhin Paul (1006140) Jawwad Sadiq Ayon (1006144) Nouroz Rahman Amon (1006163) Submission Date:01-11-2014 A PROJECT ON “REMOTE MONITORING OF A POWER STATION/ SUBSTATION (VOLTAGE MONITORING) USING GSM” Submitted to: Dr. Md. Farhad Hossain Assistant Professor, Dept. of EEE,BUET Submitted by: Jawwad Sadiq Ayon (1006144) Abdullah Al Arafat (1006135) Tuhin Paul (1006140) Nouroz Rahman Amon (1006163) Submission Date: 01-11-2014 Bangladesh University of Engineering & Technology Course No: EEE 310

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Objectives:
The purpose of this project is to monitor the remote electrical parameters like Voltage, Current ,Phase angle and Frequency (N.B.:in this project only voltage has monitored)of power station/substation and send these real time values over GSM network using GSM Modem/phone at power station/substation.
Abstract of the Project:
User can monitor the remote electrical parameters by receiving commands in the form of SMS messages .In this project we make a prototype of electric substation the voltage of which will be monitored by the user. This system also can automatically send the real time electrical parameters (in this project we have shown monitoring voltage parameter only) periodically (based on time settings) in the form of SMS. This project makes use of an arduino board which is commonly termed as arduino mega 2560. The Adc pins can efficiently communicate with the different sensors being used. The microcontroller in the arduino board is provided with some internal memory to hold the code. The code is programmed using arduino programming language
Introduction:
Monitoring of substations are essential task for supplying healthy power to the consumers in this automated era. Depending on the voltage levels and end users, there are transmission or distribution substations those supply electrical power to various loads. Remote monitoring make these substations to be operated through wireless communication technologies like GSM, GPRS, Ethernet, etc.
Substations consist of various equipment like transformers, circuit breakers, relays, APFC panels, etc., and these equipment ought to be operated in such a way that the loads must be delivered safely with

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specified parameters. These parameters include voltage, current, frequency, power factor, temperature, and so on. The following GSM based project deal with substation monitoring aspects. Here in this project we made a prototype of substation and only one parameter voltage is to be remote monitored.
Major Equipment Used :
1. 1x 16×2 parallel LCD display (compatible with Hitachi HD44780 driver)
2. 1x Arduino Board
3. 1x 10kΩ and 1x5kΩ potentiometer
4. 5x 10kΩ resistor
5. 4.4kΩ resistor using a bunch of different resistors.
6. SIM-908 GSM module
7. GSM Antenna
8. Jumper Wire
9. Power supply for SIM908
10. Breakout Board,
Algorithm for Measuring Voltage using Arduino:
This project shows how to make remote voltage monitoring system with Arduino. It uses voltage divider concept to estimate the voltage input .Each analog input of Arduino has 1024 steps from 0 to 5 volt. This experiment used a simple voltage divider to measure roughly 0 to 12 volt (using 50k as

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R1 and 4k3 as R2).By varying the values of R1 and R2, the precision and range of the measurement can be changed.
The analog inputs of an Arduino can measure up to 5V (when using the built-in analog reference voltage). Even when only connecting to a 5V circuit, we have used the resistors to help protect the Arduino from short- circuits or unexpected voltage surges.
Those two resistors form a potential divider that is used to lower the voltage being measured to a level that the Arduino can read. This actually extends the range that can be used. For example, if resistors are used to halve the input voltage then the Arduino can effectively read up to 10V (since 10V will be read as 5V, 5V will be read as 2.5V…). This comes at the expensive of accuracy – the ADCs in the Arduino can read up to 1024 different levels between 0V and 5V. By expanding the range to 10V, those 1024 levels are spread across a wider range and are therefore less able to detect small changes.
You can increase the resistance value of R2, then the maximum voltage that can be read will be decreased; giving a slightly more accurate reading. With R1 at 100Ko and R2 at 10Ko, the input voltage is reduced by a factor of around 11 – allowing the monitoring system to read from 0V–55V.
The analog sensor on the Arduino board senses the voltage on the analog pin and converts it into a digital format that can be processed by the microcontroller. Here, we are feeding the input voltage to the analog pin

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(A0) using a simple voltage divider circuit comprising resistors R1 (50k) and R2 (4.4k) – allowing the monitoring system to read from 0V–61V.
The formula for calculating values in a potential divider is:
Here,
Vout=(R2/(R1+R2))*Vin
So,
Vin = Vout / (R2/(R1+R2));
When measuring the voltage in the loop() routine, analogRead(0) is used to read the level from analog input 0. The returned value is an integer in the range 0 through 1023, so it must first be adjusted to a range 0 through 5. This is done by multiplying it by the power supply level, and then dividing by 1024.
Vout = (value * 5.0) / 1024.0

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When measuring the voltage in the loop ( ) routine, analogRead(0) is used to read the level from analog input 0. The returned value is an integer in the range 0 through 1023, so it must first be adjusted to a range 0 through 5. This is done by multiplying it by the maximum power supply level, and then dividing by 1024.
The 10k Potentiometer controls the contrast of the LCD panel. Nothing fancy here.
Code:
const int timesTosend=10;
int count=0;
// include the library code:
#include <LiquidCrystal.h>
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);
// variables for input pin and control LED
int analogInput = 1;
float vout = 0.0;
float vin = 0.0;
float R1 = 50000.0; // !! resistance of R1 !!
float R2 = 4400.0; // !! resistance of R2 !!
// variable to store the value
int value = 0;
void setup()
{
Serial1.begin(9600); //Baud rate of the GSM/GPRS Module
Serial.begin(9600);
// Send ANSI terminal codes
Serial.print("x1B");
// End ANSI terminal codes
// declaration of pin modes
pinMode(analogInput, INPUT);
// set up the LCD's number of columns and rows:
lcd.begin(16, 2);
lcd.setCursor(0, 0);
lcd.print("Monitor System!");
lcd.setCursor(0, 1);
lcd.print("Vin=");
}
void loop()
{
while(count<timesTosend){
value = analogRead(analogInput);
vout = (value * 5.0) / 1024.0;

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vin = vout / (R2/(R1+R2));
if (vin<0.50) {
vin=0.0;
}
Serial.println("--------------------");
Serial.println("Substation Voltage Monitoring:");
//Serial.print("Maximum Voltage: ");
Serial.println("Vin=");
Serial.println(vin);
Serial.println("--------------------");
Serial.println("");
Serial1.print("r");
delay(1000);
Serial1.print("AT+CMGF=1r");
delay(1000);
Serial1.print("AT+CMGS="+8801818796089"r"); //Number to which you want to send the sms
delay(1000);
Serial1.print("System Voltage=");
delay(100);
Serial1.print(vin);
delay(100);
Serial1.print("V");
delay(100);
Serial1.write(0x1A);
delay(1000);
//print result to lcd display
lcd.setCursor(4, 1);
lcd.print(vin);
lcd.print("V");
delay(6000);
count++;
}
}
The Serial Port Monitor in the IDE is used to view the messages sent by this sketch. However, this is not a particularly advanced monitor, and cannot display the ANSI terminal sequences that are used to provide a friendlier display. Better results can be had by using a terminal package such as Hyperterminal, RealTerm or Putty.
The serial port we need to connect to is found from the Arduino IDE:
 On the Tools menu, we have clicked Serial Port and looked for the item that is ticked.
The other setting we have used are:

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Display:ANSI
Speed:9600
Parity:Non
Data bits:8
Figure: Prototype of a substation
Monitoring System developed by our project:
The values of voltage is directly applied to one of the adc input pin of the arduino. Along with this, a lcd display is connected. The monitoring PC is connected to the main station. The arduino at the substation monitors and

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captures the voltage values for a particular period of time interval. The captured values are stored in the data register and displayed using the LCD display.
The monitored voltage are transmitted using the gsm modem for each and every time interval programmed in the code. A gsm antenna tuned for the
selected RF frequency can be utilized for the transmission of the RF signal but the antenna has to exhibit a unidirectional radiation pattern. In the receiver side of the user profile, the receiver antenna converts the RF signal into electrical signal and acquires the information which has been transmitted by the transmitter. Based on the received information, controlling operation is performed. If the receiver receives the substation parameters which is greater than the fixed threshold level, then immediately the units is shutdown so as to protect the same.

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Figure: SIM908 module with breakout board.
Sending SMS from GSM
We used a grameenphone sim in our project.This is the procedure how we sent SMS through GSM:
1.First of all GSM was woken up by sending AT command
2.The GSM was put on Text mode by feeding command AT+CMGF=1
3.then we have given the command AT+CMGS=”Mobile_number”
4.Then we wrote the messages to be sent via gsm.
5.Press CTRL+Z to send the SMS by writing Serial.write(0x1A)
The above steps were coded for Arduino to handle automatically
Special Feature of this project :
1. Substation/power station voltage can be monitored from anywhere in the world.
2. Feedback of the devices being operated can also be developed.
3. Efficient and low cost monitoring system.
4. Easy to monitor and user friendly.
5. Real time monitoring .
Constraints:
1. Depends on the network signal strength.

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2. Power consumption is pretty high.
Problems we face:
1. The power supply was too much sensitive.
2. If the voltage goes down crossing a certain limit the module automatically shuts down.So, during the time of completeing project we faced little bit trouble working with it.
3. Again at the starting of the module it drives a huge amount of curren nearabout 2 Amp.So, it was a challenge for us to meet this current requirement.
Cautions taken:
Working with electricity, even at low voltages, can be dangerous. There a risk of damage to equipment like arduino mega 2560 or expensive SIM908 and ourself – .We carefully made connections of the components and followed the instructions provided in datasheet very carefully, and sought advice and help others who previously worked on gsm based project as we are newbies to SIM908 module.
We’ve disconnected GSM from Arduino while Uploading the code to Arduino .
While issuing ATH command we use Serial.println & not Serial.print.This println is to send Carriage Return a-fter the ATH command.Again the reasonable amount of Delay (6secs) are used after issuing the one sms.
This delays in the code are mandatory for GSM to respond.
Future Scope and Plan:
Our project arduino based substation/power station monitoring with gsm is mainly intended to monitor parameters like voltage through a GSM based mobile phone. The arduino is programmed in such a way that if a particular

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fixed format of sms is sent from GSM modem to mobile phone, which is fed as output from the arduino .A return feedback message will be sent from the mobile to GSM modem.
The temperature, current, phase angle, frequency at the substation where devices are being operated can also be known using this object.
In future we can use this project in several applications by adding additional components to this project.
This project can be extended by using GPRS technology, which helps in sending the monitored and controlled data to any place in the world.
By connecting wireless camera in substation user can see the entire equipments from our personal computer only by using GPRS and GPS technology. The monitoring of the devices can be done from the personal computer and we can use to handle so many situations.
By connecting temperature and current sensor, we can get the temperature of dangerous zones in industries and we can use personal computer itself instead of sending human to there and facing problems at the field. The system will detect the substation parameters and it gives information to the arduino and arduino gives the information to the user mobile phone through gsm.
We can certainly measure current,phase angle by developing the circuitry.This can be modified and developed to make a successful smart grid system.Again we can turn it to a smart energy meter by which electricity parameters along eith the cost calculation can be monitored by the user by gsm or gprs and they can minimize their electricity uses to a optimum level.This project can be a little starting to reduce the electricity loss by monitoring the electricity use both in the pick and off pick hour and the user can control the use of big reactive system like conditioning,oven,motor,etc.Again if any office or house generate electricity by using renewable power plant,the user can monitor the generation and again the electricity authority can also be aware of this generation level by monitoring the voltage level using this project and the idea. Moreover the project can be developed to a level to supply the local

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level electricity generation to the national grid by using this monitoring project.
Conclusion:
The project “REMOTE MONITORING OF A POWER STATION/ SUBSTATION WITH GSM” was designed such that the substation parameters can be monitored and also controlled from anywhere in the world using GSM connected to mobile phone. Using highly advanced gsm module with the help of dedicated power supply, the project has been successfully implemented. Thus the project has been successfully designed and tested.

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