Single phase and three phase capacitive-load switching in transmission & distribution systems

The interruption of capacitive currents is a usual switching case, unlike the making and breaking of fault currents. The usual cases, in which a capacitive current is switched, are switching... Read more

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The 4 most common switchgear-based substation types

The subject of this article is to discuss few most common types of MV/HV power substations based on the type of distribution switchgear, which can be seen in every distribution... Read more

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The zone selective interlocking logic of protection relays

This function significantly reduces the tripping time of the circuit breakers closest to the source. It can be used for zone selective interlocking (ZSI) in closed ring networks. It applies... Read more

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Protocols applied for time synchronization in a digital substation automation

Substation automation is a mission-critical task and electric power utilities must synchronize across large-scale distributed power grid switches in a substation to enable smooth power trans-fer and maintain power supply... Read more

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The study of harmonics and LV energy compensation

The harmonic currents are mainly down to the nonlinear loads in the installations. The most frequent harmonic sources are linked to the use of electric arcs (welding, arc furnaces, discharge... Read more

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Practical tips on how not to burnout an electric motor

There are many reasons why an electric motor could start heating up. For example, when another starting duty is used than the informed one on the motor nameplate this may... Read more

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Effects of unbalanced Electrical Load (Part:2)

  • Harmonics in system by UPS:

  • UPS or inverter supplies also perform with poor efficiency and inject more harmonic currents in case of unbalances in the system
  • Decrease Life cycle of Equipment:

  • Unbalanced Voltage increase I2R Losses which increase Temperature. High temperatures, exceeding the rated value of a device, will directly decrease the life cycle of the device and speed up the replacement cycle for the device, and significantly increase the costs of operation and maintenance.
  • Relay malfunction

  • Unbalanced Voltage flows Negative and Unbalanced Voltage of Voltage or Current.
  • The high zero-sequence current in consequence of voltage imbalance may bring about malfunctions of relay operation or make the ground relay less sensitive. That may result in serious safety problems in the system.
  • Inaccurate Measurement

  • Negative and zero-sequence components of voltages or currents will give rise to inaccurate measurements in many kinds of meters.
  • The imprecise measured values might affect the suitability of settings and coordination of relay protection systems and the correctness of decisions by some automated functions of the system.
  • Decrease Capacity of transformers, cables and lines

  • The capacity of transformers, cables and lines is reduced due to negative sequence components. The operational limit is determined by the RMS rating of the total current, due to ‘useless’ non-direct sequence currents the capacity of equipment is decrease.
  • Increase Distribution Losses

  • Distribution network losses can vary significantly depending on the load unbalance.
  • Unbalance load increase I2R Losses of distribution Lines.
  • Increase Energy Bill by increasing Maximum Demand

  • Unbalanced Load increase maximum Demand of Electrical supply which is significantly effects on energy bill. By load balancing we can reduce energy bill.
  • For Energy Consumption Energy Supply Company does not charge on kVA but on kW for Residential customers. This means that they are charged for the “actual” energy used and not charged for the “total” energy supplied. Thus the power factor and Maximum Demand do not impact residential customers.
  • But Commercial, Industrial and H.T Connection charged by its maximum demand . We have to specify the maximum “demand“(in kVA) at the time of connection. During the month if you exceed your maximum “demand” you have to pay penalty (or extra price) for the same. That is the MDI penalty that appears on electricity bills.
  • Let’s assume That Two Company has same approved load of 40 KW and runs 30KW for 100 hours.
  • Electricity charge = 65 Rs per kWh
  • Demand charge = 210Rs per kW
  • Example 1: Company A runs a 30 KW loads continuously for 100 hours but It’s Maximum Demand is 50KW
  • 30 KW x 100 hours = 3,000 KWh
  • Energy Consumption Charge =3000×65=195000Rs
  • Demand difference = 50 KW-40KW=10KW
  • Demand Charges = 10X210=2100Rs
  • Total Bill:  195000+2100=197100Rs
  • Example 2: Company A runs a 30 KW loads continuously for 100 hours but It’s Maximum Demand is 40W
  • 30 KW x 100 hours = 3,000 KWh
  • Energy Consumption Charge =3000×65=195000Rs
  • Demand difference = 40 KW-40KW=0KW
  • Demand Charges = 0X210=00Rs
  • Total Bill:  195000+0=195000Rs
  • Failure of Transformer

  • Three-phase voltage with high unbalanced may cause the flux inside the transformer core to be asymmetrical.
  • This asymmetrical flux will cause extra core loss, raise the winding temperature and may even cause transformer failure in a severe case.
  • Ideally any distribution transformer gives best performance at 50% loading and every electrical distribution system is designed for it. But in case of unbalance the loading goes over 50% as the equipments draw more current.
  • The efficiency of transformer under different loading conditions
  • Full Load- 98.1%
  • Half Load- 98.64%
  • Unbalanced loads- 96.5%
  • For a distribution transformer of 200KVA rating, the eddy currents accounts for 200W but in case of 5% voltage unbalance they can rise up to 720W.
  • Bad / Loose connection of neutral wire

  • In balance Load condition Bad connection of Neutral wire does not make more impact on distribution System but in unbalance load condition such type of Bad neutral connection make worse impact on distribution.
  • The Three Phase power supplies a small a three-floor building. Each floor of this three-floor building is serviced by a single-phase feeder with a different phase. That is the first, second and third floor are serviced by phase R, Y and B. The external lighting load is connected only on R Phase.
  • The supply transformer is rated at 150 kVA and connected delta-grounded wye to provide for 430/220 V three-phase four-wire service.
  • This Transformer has a loose or Bad Neutral connection with the earth.
  • The transformer delivers a load of 35 kVA at 220 V with 0.9 power factor lagging to each floor.
  • During the daytime on, most of the Load of the Building are distributed equally over the three floors which is R Phase=30A, Y Phase =32A, B Phase=38A.
  • In Daytime The Bad connection of Neutral does not effected the Distribution system due to equal load distribution of the System
  • However it is not case in Nighttime. the Load on Y Phase and B Phase are negligible but R Phase Load is high compare to Y and B Phase.
  • In R Phase due to High Electrical Load and The fluorescent lamps flash frequently during the Nighttime of external Lighting Load
  • In Night time a bad electrical contact of the neutral wire of the supply makes the high contact resistance between the neutral wire and connector .which was about 15 kΩ.
  • This extra high impedance caused an unusually high voltage drop in the phase a circuit. In this case, the voltage of phase a dropped from the normal 220V to 182.5V, about 17% based on the nominal voltage. If the contact impedance goes higher than 20 kΩ, it may result in more serious conditions such as extinguishing all lamps.
  • This problem can be removed by fixing the bad connection and keeping the contact impedance near to zero.
Neutral Wire Contact Resistance Voltage across  bad Connection Point Voltage across  Transformer Secondary Side
Day Time Night Time Day Time Night Time
R Y B R Y B R Y B R Y B
Proper Connection (0Ω) 0v 0v 0v 0v 0v 0v 220v 220v 220v 220v 220v 220v
Bad Connection (15Ω) 0v 0v 0v 40v 0v 0v 220v 220v 220v 182v 220v 220v
  • Neutral wire broken

  • The effect of a broken neutral makes voltage imbalance in a Three Phase Four Wire System.
  • For a Three Phase Four Wire System, high neutral wire impedance might enlarge a voltage imbalance (Some Phase Voltage increase while some Phase Voltage decreases).
  • High Voltage damage the equipment connected and even destroy on other hand low voltage effect operation of equipments.
  • The Three Phase star connected lighting loads are fed by a 430 V balanced three-phase voltage source. The fluorescent lamps are all rated at 220 V, 100 W each. The lamps are not equally in R Phase 5 No’s of Bulbs are connected, in Y Phase 3 No’s of Bulbs are connected and on B Phase 3 No’s of Bulbs are Connected. And, the normal impedance of the neutral wire is 1Ω
  • In unbalanced three phase load arrangement, high neutral wire impedance will enlarge the voltage across the neutral wire. The voltages of phases B and C at the load terminal raised to 255 V and 235 V, respectively, and gaining 16.15% and 5.77% based on rated voltage. These abnormally high phase voltages might damage the lamps in phase B and C.
  • On the other hand, the voltage in phase A was reduced from 220V to 185V. That might cause the lamps to flash.
  • If the broken neutral line problem is fixed, then the three phase voltages will go back to normal in near balanced status .however, if the loads are distributed equally to the three phases this problem can also be removed or minimized.
Conditions Voltage across the neutral wire Voltage at  the load terminal
R Y B R Y B
Normal Condition 1v 1v 1v 220v 220v 220v
Neutral Broken 0v 0v 0v 182v 255v 235v
  • Unsuitable capacitor bank installation

  • For reducing energy loss, utilities always force their customers to maintain the power factor within a limit. Penalty will be applied to the customers if their loads’ power factors run outside the limits.
  • Installation of shunt capacitor banks is the most common and cheapest manner to improve the power factor. However, unsuitable installation (single Phase Capacitor instead of Three Phase Capacitor ) may make it worse.
  • The supply transformer is rated at 150 kVA, 11kV/430 V, and supplies a three-phase load of 105 kVA with power factor 0.7 lagging.
  • A single-phase 20KVAR capacitor bank is connected to B phase to improve system power. The impedance of the shunt capacitor bank is 1.805Ωper phase.
  • This kind of single phase Capacitor installation should make the system unbalanced. This unsuitable installation consumes extra real power of 44355 W.
  • The extra real power consumption = 1.732x2XV(RB) / 4xXc =(1.732x2x430) / (4×1.805) =44355W
  • This case shows that the system balance should be considered when installing a capacitor bank to correct the system power factor for a three-phase power distribution system.

 Remedial Action to prevent unbalances Load:

  • All the single phase loads should be distributed on the three phase system such that they put equal load on three phases.
  • Replacing the disturbing equipments i.e. with unbalanced three phase reactance.
  • Reducing the harmonics also reduces the unbalance, which can be done by installing reactive or active filters. These filters reduce the negative phase sequence currents by injecting a compensating current wave.
  • In case the disturbing loads cannot be replaced or repaired, connect them with high voltage side this reduces the effects in terms of percentage and even controlled disturbance in low voltage side.
  • Motors with unbalanced phase reactance should be replaced and re-winded.
  • Distribution of single-phase loads equally to all phases.
  • Single-phase regulators have been installed that can be used to correct the unbalance but care must be exercised to ensure that they are controlled carefully not to introduce further unbalance.
  • Passive network systems and active power electronic systems such as static var compensators and line conditioners also have been suggested for unbalance correction.
  • Load balancing.
  • Use of passive networks and static VAR compensators.
  • Equipment that is sensitive to voltage unbalance should not be connected to systems which supply single-phase loads.
  • Effect of voltage unbalance on ac variable speed drives can be reduced by properly sizing ac side and dc link reactors
  • Tight all Neutral Connections of the System.
  • Install Proper size of Capacitor Bank to the System.
  • Load Scheduling, where the loads in an electrical network are scheduled in a way to turn on and off at precise times to prevent the overloading of any one phase.
  • Manual Load Shifting, where an electrician opens a breaker panel and physically removes the loads from one phase and inserts them onto another phase.
  • Load Shedding, where the loads in an electrical network are immediately turned off in order to instantly “rebalance” the phases. This is usually done by ranking the loads in a network by how long they can be turned off before it affects operations

 



August 14, 2018 at 10:16PM by Department of EEE, ADBU: https://ift.tt/2AyIRVT

The fundamentals of protection relay co-ordination and time/current grading principles

Transmission and distribution systems are exposed to overcurrent flow into their elements. In an electric power system, overcurrent or excess current is a situation where a larger than intended electric... Read more

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Automatic Plant Watering & Irrigation System – Circuit, Code & PDF

Automatic Plant Watering System – Full Source Code + Circuit +  Free PDF Download

Introduction

In daily operation related to watering the plants are the most important cultural practice and the most labour-intensive task. No matter whichever weather it is, either too hot and cold or too dry and wet it is very crucial to control the amount of water reaches to the plants. So, It will be effective to use an idea of automatic plant watering system which waters plants when they need it. An important aspect of this project is that: “when and how much to water”. To reduce manual activities for the human to watering plant, an idea of plant watering system is adopted. The method employed to monitor the soil moisture level continuously and to decide whether watering is needed or not, and how much water is needed in plant’s soil. This project can be grouped into subsystems such as; power supply, relays, solenoid valve, Arduino GSM shield, Soil moisture sensor and LCD.Automatic Plant Watering & Irrigation System - Circuit, Code & PDF

Essentially, system is design and programmed in such way that soil moisture sensor senses the moisture level of plants at particular instance of time, if moisture level of sensor is less than the specified value of threshold which is predefined according to the particular plant’s water need then the desired amount of water is supplied till it reaches to the predefined threshold value.

System reports its current states and sends the reminder message about watering plants and to add water to the tank. All this notification can be done by using Arduino GSM shield.

Aim of the project:

Since nowadays, in the age of advanced technology and electronics, the life style of the human should me smart, simpler, easier and much more convenient. So, therefore; there is a need for many automated systems in human’s daily life routine to reduce their daily activities and jobs. Here an idea of one such system named as automatic plant watering system is very useful. As many people are facing a lot of problem watering the plants in the garden, especially when they away from the home. This model uses sensor technologies with microcontroller in order to make a smart switching device to help millions of people.

In its most basic form, system is programmed in such a way that soil moisture sensor which senses the moisture level from the plant at particular instance of time, if moisture level of the sensor is less than the specified value of threshold which is predefined according to the particular plant than the desired amount of water is supplied to plant till it’s moisture level reaches to the predefined threshold value. System involves humidity and temperature sensor which keep tracks the current atmosphere of the system and has an influence when watering happens. Solenoid valve will control the water flow in the system, when Arduino reads value from moisture sensor it triggers the solenoid valve according to the desired condition. In addition, system reports its current states and sends the reminder message about watering plants and gets SMS from the recipient. All this notification can be done by using Arduino GSM shield.

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Block Diagram of Automatic Plant Watering System

Background of the System

It has been studied in the school from the science’s books that the plants are very imperative for all the humanity in many aspects. As they keep the environmental clean by producing fresh oxygen time to time. Automatic plant watering system have been seen becoming much more with the rise in the everyday objects being connected to the advanced technologies, these systems are implemented at a growing rate. Places like homes as well as on industrial levels. The main use of these systems is efficiency and easy to use.

Plant watering system provides the ability to plant lovers to take of their home plant while they are away – through the use of efficient and reliable components such as different types of sensor technologies.

There are several different/uncomplicated types of indoor plant watering system, depending on the level of automation needed.

In the final pdf report (free downloadable link is given at the end of the post content), the following sections are described in details.

  • Plant Watering Globes and Spike
  • Indoor Drip Watering System
  • Sensor Technology
  • Temperature and Humidity Sensors
  • Temperature Sensor
  • Humidity Sensors
  • Soil Moisture Sensors
  • Bi-Metallic Thermostat
  • Thermistor
  • Resistive Temperature Detectors (RTD)
  • Thermocouples
  • Sensor ICs, LM35
  • Digital Temperature Sensor (ADT7301)
  • DHT11 and DHT22
  • GSM Module
  • GSM Architecture
  • Relay
  • Transistor
  • Hitachi 16×2 LCD

Related Project: What is ATMega Microcontrollers & How to Make an LED Project with it?

Products & Components Specifications

Requirement ID SRS-GSM-001
Title GSM Module
Description System includes the GSM module, which sends alert SMS to the recipient and receive a SMS from the user.
Version Version 1.0
Requirement ID SRS-Microcontroller -001
Title ATmega328p
Description System includes the microcontroller which usually comes with Arduino Uno. this microcontroller reads the reading from the sensor and controls the overall system.
Version Version 1.0
Requirement ID SRS-Temperature and Humidity-001
Title DHT11
Description System includes the temperature and humidity sensor, which keeps track of the current temperature and humidity values from the surrounding and sends the reading back to microcontroller.
Version Version 1.0
Requirement ID SRS-Moisture-001
Title Grove Soil Moisture Sensor
Description System includes the soil moisture sensor, which takes the reading from the moisture of the soil and sends the reading back to microcontroller.
Version Version 1.0
Requirement ID SRS-LCD-001
Title Hitachi 16×2 LCD
Description System includes the LCD interface for the user, which displays the reading taken by the different sensors in the system.
Version Version 1.0

Arduino Based Automated Plant Watering System:

Automatic Plant Watering Block Diagram

Schematic Circuit Diagram of Automatic Plant Watering & Irrigation System

Schematic Circuit Diagram of Automatic Plant Watering & Irrigation System

According to this system there are two functional components in this project i.e. Moisture sensor and motor/water pump. In its most basic form moisture sensor senses level of the soil moisture. Then motor/water pump supplies water to plants.

Click image to enlargeSchematic Circuit Diagram of Automatic Plant Watering & Irrigation System

Schematic above in above figure describes the overall behaviour of the system. Project uses Arduino Uno to controls the motor. It consists of H-bridge which controls the flow of servo motor i.e. clock or anti clock direction. Moisture sensor measures the level of soil and sends the signal to Arduino then Arduino will open the servo motor if watering is required. Then the motor/water pump supplies water to the plants until the desired moisture level is reached.Automatic Plant Watering & Irrigation System - Final Circuit

Form the prototype in above figure moisture sensor senses the moisture level and sends the signal to Arduino and then Arduino opens water pump with the help of H-bridge and waters the particular plant. This is done by using Arduino IDE software.

Project Design

This section is talk about any work finished in software design and hardware design. It also goes into insight about what the system includes and why different components were chosen to make a fully completed Automated Plant watering system. Consider a diagram in figure shows the basic conceptual model of the system using chosen components.Automatic Plant Watering project design block diagram

The functionality of block diagram shown in above figure of the automated plant watering system is illustrated below:

  • The system includes GSM module which sends SMS to the recipient and receives SMS from the recipient.
  • It uses soil moisture, temperature and humidity sensors.
  • It also includes solenoid valves along with solenoid circuit which controls the flow of water through the solenoid valves.
  • The moisture sensor is used to determine the moisture level of the particular plant. This moisture level is read by the microcontroller, as it loops around and sees if the value from the sensor is above the threshold value or not. If the value is above the predefine value than GSM module is ready to send a SMS to the recipient.
  • The temperature and humidity sensor is used to determine whether it is too hot for the plant or the humidity is too high to handle. This is read by the ATmega328p (Read more about What is ATmega) chip on Arduino Uno. these reading will be used to determine if all the solenoid in the system should be On or Off.

More components details can be found in the pdf file (below)

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Hardware Design

Sensor Schematic

Figure below shows the schematic of the Sensor circuit. As all the sensor connected with the Arduino analogue pin A0-A3. Pin A0 was reserved for the temperature and humidity sensor whereas pins A1-A3 were reserved for moisture sensors. All the sensors have common power 5V and Ground as shown in the schematic.Sensor Schematic

LCD Schematic:

Figure below shows the schematic of the LCD. Digital pin 8 – 13 was reserved for the LCD as shown in the Schematic. Pin 1 and Pin 3 are the power and ground whereas pin 2 is the contrast pin on the LCD which controls the contrast and connected with the potentiometer. It must be kept in mind while connecting LCD is that digital pins from Arduino and data pins from LCD has to be connected in correct order otherwise LCD will display only garbage on the screen.LCD Schematic

Solenoid Schematic

Diagram underneath in figure below shows the circuit diagram of the solenoid circuit. Digital pin 4 – 7 was reserved for the Solenoids. As the circuit consists of relays, transistors, resistors, and LEDs instead of the solenoid (CadStar doesn’t have Solenoid symbol). In the schematic relays utilizes 5V. Whereas 5V also goes into NO channel of the relays as well this is because in the schematic LEDs replaces solenoid which works on (5V) followed by 220-ohm resistor.

So, when the voltage is applied to the base of the transistors. Transistor switches to ground allowing the coil of the relay to get magnetized and switches itself to Normally closed channel, due to which LED connected to that particular relay comes On and when the voltage applied on the transistor base is drops, transistor switches itself back to normal and the coil of the relay get de-magnetized and relay switches to NO channel again, due to which LED goes Off again.Solenoid Schematic

After finishing off all the Schematic of the circuit, next step is to build them on the Veroboard. It is important to design the circuit on stripboard layout planning sheet in advance because there are certain principles for designing a circuit on Veroboard which is as follows:

  1. Mark out the Vs and GND power line first on the top right of the stripboard layout planning sheet.
  2. Remember to cut the track between the pins of an IC. Mark the cuts on the diagram with an X.
  3. Try to make resistor and axial capacitors lay flat on the stripboard. Resistors usually require a gap of 4 holes, capacitor a gap of 8 holes.
  4. If possible numbers the pin of the ICs.The bottom side of the Veroboard consist of the copper tracks in which voltage flows works horizontally. Different Veroboard design of the schematics above are shown below:

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Software Design

After getting the hardware done, it’s time to test the hardware with the software. In this section, the implementation of the software design will be described in detail for each of the different automation/ technologies used within the system. This includes the Arduino code written and uploaded to the Arduino.

The first thing done was to get the solenoid circuit working and how the solenoid would act from the microcontroller perspective. For this, a small flow chart was done which can be seen under software flow section in figure above.

Arduino IDE was used to get the upload the software on the Arduino. For the basic solenoid circuit, a simple program was written which basically blinks the LED every 1 sec. digital pin 4, 5, 6 and 7 was defined initially which test the program and the circuit. So, when the program runs it makes all basic initializations, defines all the output pins in void setup () and then jumps into the void loop () where it constantly runs and blinks LEDs on every 1sec.

After that, a small program was written and uploaded to the Arduino which gets the readings from the different sensor and prints them on the LCD.  For this, a small flow chart was done which can also be seen under software flow section in the given figure. When the program goes into the void loop () it gets the readings from the sensor and does all the basic calculation and prints them on LCD.

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Next thing is to upload the software for GSM module to the Arduino, through which GSM could communicate with the microcontroller. Modem test was done initially which does all the basic initialization and libraries for the GSM and gets the IMEI number and see if the modem is functioning properly once start communicating with Arduino. The next step is network connection test which basically initialized the GSM and displays all the other network which GSM module can support.

Once the GSM module is tested and functioning properly it’s time to use GSM module to communicate with the recipient, which means sends SMS to the recipient and receive SMS from them. In order to do that, another simple Arduino wiring program was written and uploaded to the Arduino. The program initialized the GSM and send SMS to the recipient in contrast another Arduino program was written in which GSM receive the SMS from the end user.

Finally, once all the software design was done it’s time to merge all the software design together and build a final working software for the system. Different algorithm approaches were applied which can be seen under software flow section to get the final software working and does it what it supposed to do. The above figure shows the working of the final software where it takes a reading, send SMS, receive SMS and start doing what it was doing previously.

Note: All the software code can be seen in the appendix below.

NOTE: all the software code can be viewed in the appendix. The output from the modem test and network connection test was not included in the report because the actual report was done after the submission of hardware.

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Project Construction and  Software Testing

After getting all the hardware and software design done successfully it’s time for the project construction and testing. In this section of the report, details will be given on how the different hardware design gets implemented and tested. This section also talks about if there was any hidden problem within the software code that was important to troubleshoot and evacuate and to build the project successfully. the step by step process can be seen in the full project report in pdf file given below such as construction and testing procedure.

Software Testing

Software testing phase is also an important aspect of the project development. Software testing is a procedure of executing a program or application with the goal of finding the software bugs. It can likewise be expressed as the process of validating and verifying that a software program or application meet its technical requirement, works as accepted and can be executed with a similar trademark. To do the software testing different approaches were adopted. A software requirement specification (SRS) document was written which fully addressed the expected behaviour of a software system.

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Requirement ID SRS- Sensor -010
Title Sensor
Description Sensors in the system take the readings and send it back to the microcontroller.
Version V 1.0
Requirement ID SRS- Data -020
Title Data Display
Description When the users try to get the reading from the system. Display should have displayed data to user for example: temperature and humidity value followed by moisture readings.
Version V1.0
Requirement ID SRS- Microcontroller -030
Title Microcontroller
Description Microcontroller in the system act as a brain of the system which manages everything in the system
Version V1.0
Requirement ID SRS- Latch -040
Title Latch
Description Latch in the system expands the digital pins for the microcontroller
Version V1.0
Requirement ID SRS- GSM-050
Title GSM
Description System will react by sending a SMS alert to the recipient whenever microcontroller tells it to do so.
Version V1.0

After writing the SRS document software design moved in to static testing phase which includes reviewing of the document. This is where verification of the requirements occurs. There are four diverse types of verification methods defined below:

  1. Inspection (I):  control or visual verification
  2. Analysis (A): verification based on analytical evidences
  3. Demonstration (D): verification of operational characteristics, without quantitative measurement.
  4. Test (T): verification of quantitative characteristics with quantitative measurement. For each requirement of the SRS document, a verification method is defined with abbreviation of I, A, D and T.

Verification:

Requirement ID Requirement Title Method
REQ-010 Verify that the sensors of the system get readings I
REQ-020 Verify that the Data is Displayed on the screen. D
REQ-030 It is verified that the microcontroller of the system is managing or working properly as it gives 100% result for every request. D
REQ-040 Verify that latch circuit was doing what is supposed to do. That take sin 3 input and spits out 8 pins A
REQ-050 Verify that the SMS has been sent and received by GSM D

Results

As all the testing done with satisfactory result. Since there is no as such particular result that has to be documented. As the system works with moisture and DHT11 (temperature and humidity) sensor which takes reading according to the current room temperature and humidity. Readings from the moisture sensor in the circuit also depend on what the current moisture level is for the plant. Otherwise, overall result coming out from the circuit in terms of functionality was good for motivation.

Related Post: Arduino PWM Programming and its functions in Arduino

Final and full software code for Automatic Watering plants & irrigation systems

Note: More Codes related to the project can be find in the pdf file such as sample Code to test Solenoid Valve, Code for testing System Sensors, GSM Modem Test Code, GSM Network Connection Code, GSM sends SMS alert Code, GSM Receive SMS code,

Final Auto Watering Plants Project Code

#include <dht.h>
#define dht_dpin A0
dht DHT;
//———————–
#include <LiquidCrystal.h>
LiquidCrystal lcd (8, 9, 10, 11, 12, 13);
//———————————-
int plantPotMoisture[3] = {A1, A2, A3};
//———————
#include <GSM.h>
#define PINNUMBER “”
GSM gsmAccess; // include a ‘true’ parameter for debug enabled
GSM_SMS sms;
char remoteNumber[] = “0899506304”;
String moistureMessage = “Moisture is Low on sensor: “;
String SMS_Alert = “Sending SMS!”;
String humidityMsg = “Humidity is High. Open All Solenoids”;
String tempMsg = “Temperature is too HIGH!..Open ALl Solenoids “;
String messageBuffer = “”;
char senderNumber[20];
String stringOne = “Opens1”;
String stringTwo = “Opens2”;
String stringThree = “Opens3”;
String stringFour = “OpenAll”;
//—————
#define solenoidData 5
#define solenoidClockster 4
#define solenoidLatch 6
//—————
const int master = 0;
const int slave1 = 1;
const int slave2 = 2;
const int slave3 = 3;
boolean takeReadings = true;
int serialSolenoidOutput = 0;
void setup()
{
pinMode(solenoidData, OUTPUT);
pinMode(solenoidClockster, OUTPUT);
pinMode(solenoidLatch, OUTPUT);
digitalWrite(solenoidLatch, HIGH);
digitalWrite(solenoidLatch, LOW);
shiftOut(solenoidData, solenoidClockster, MSBFIRST, 0);
digitalWrite(solenoidLatch, HIGH);
//————————-
Serial.begin(9600);
lcd.begin (16, 2);
lcd.clear();
lcd.setCursor(0, 0);
lcd.print(“Wait Until”);
lcd.setCursor(0, 1);
lcd.print(“GSM Initialized!”);
boolean notConnected = true;
while (notConnected)
{
if (gsmAccess.begin(PINNUMBER) == GSM_READY)
notConnected = false;
else
{
Serial.println(“Not connected”);
delay(1000);
}
}
}
void loop()
{
if (takeReadings)
{
moistureSensor();
TempAndHumidity ();
if (DHT.humidity > 50 || DHT.temperature > 25 && takeReadings )
{
takeReadings = false;
if (DHT.humidity > 50)
{
sendSMS(humidityMsg);
}
else if (DHT.temperature > 25)
{
sendSMS(tempMsg);
}
while (!takeReadings)
recieveSMS();
}
if (plantPotMoisture[0] > 30 || plantPotMoisture[1] > 30 || plantPotMoisture[2] > 30 && takeReadings)
{
takeReadings = false;
if (plantPotMoisture[0] > 30)
{
sendSMS(moistureMessage + “1”);
}
else if (plantPotMoisture[1] > 30)
{
sendSMS(moistureMessage + “2”);
}
else
{
sendSMS(moistureMessage + “3”);
}
while (!takeReadings)
recieveSMS();
}
}
}
void moistureSensor()
{
for (int i = 0 ; i < 3; i++)
{
lcd.clear();
plantPotMoisture[i] = analogRead(i);
plantPotMoisture[i] = map(plantPotMoisture[i], 550, 0, 0, 100);
Serial.print(“Mositure” + i );
lcd.print(“Mositure” + i);
Serial.print(plantPotMoisture[i]);
lcd.print(plantPotMoisture[i]);
Serial.println(“%”);
lcd.print(“%”);
delay(1000);
}
}
void TempAndHumidity ()
{
DHT.read11(dht_dpin);
lcd.setCursor(0, 0);
lcd.print(“Humidity=”);
Serial.print(“Current humidity = “);
Serial.print(DHT.humidity);
lcd.print(DHT.humidity);
lcd.print(“%”);
Serial.print(“%”);
Serial.print(“temperature = “);
Serial.print(DHT.temperature);
Serial.println(“C”);
lcd.setCursor(0, 1);
lcd.print(“temp=”);
lcd.print(DHT.temperature);
lcd.print(“C “);
delay(1000);
lcd.clear();
}
void sendSMS(String messageToSend)
{
Serial.print(“Sending a message to mobile number: “);
Serial.println(remoteNumber);
Serial.println(“SENDING”);
lcd.print(SMS_Alert);
Serial.println();
Serial.println(“Message:”);
Serial.println(messageToSend);
sms.beginSMS(remoteNumber);
sms.print(messageToSend);
sms.endSMS();
Serial.println(“\nCOMPLETE!\n”);
lcd.clear();
lcd.print(“Completed!!!”);
}
void recieveSMS()
{
char c;
if (sms.available())
{
lcd.clear();
lcd.print(“Message received from:”);
delay(800);
lcd.clear();
sms.remoteNumber(senderNumber, 20);
lcd.print(senderNumber);
while (c = sms.read())
{
Serial.println(c);
messageBuffer += c;
}
Serial.println(messageBuffer);
if (messageBuffer == stringOne)
{
toggleSolenoid1();
takeReadings = true;
}
else if (messageBuffer == stringTwo)
{
toggleSolenoid2();
takeReadings = true;
}
else if (messageBuffer == stringThree)
{
toggleSolenoid3();
takeReadings = true;
}
else if (messageBuffer == stringFour)
{
toggleAll();
takeReadings = true;
}
else
{
takeReadings = true;
}
messageBuffer = “”;
Serial.println(“\nEND OF MESSAGE”);
// Delete message from modem memory
sms.flush();
Serial.println(“MESSAGE DELETED”);
}
delay(1000);
}
void toggleSolenoid1()
{
solenoidWrite(master, HIGH);
delay(1000);
solenoidWrite(slave1, HIGH);
delay(1000);
solenoidWrite(slave1, LOW);
delay(1000);
solenoidWrite(master, LOW);
delay(1000);
}
void toggleSolenoid2()
{
solenoidWrite(master, HIGH);
delay(1000);
solenoidWrite(slave2, HIGH);
delay(1000);
solenoidWrite(slave2, LOW);
delay(1000);
solenoidWrite(master, LOW);
delay(1000);
}
void toggleSolenoid3()
{
solenoidWrite(master, HIGH);
delay(1000);
solenoidWrite(slave3, HIGH);
delay(1000);
solenoidWrite(slave3, LOW);
delay(1000);
solenoidWrite(master, LOW);
delay(1000);
}
void toggleAll()
{
solenoidWrite(master, HIGH);
delay(1000);
solenoidWrite(slave1, HIGH);
delay(1000);
solenoidWrite(slave2, HIGH);
delay(1000);
solenoidWrite(slave3, HIGH);
delay(1000);
solenoidWrite(slave1, LOW);
delay(1000);
solenoidWrite(slave2, LOW);
delay(1000);
solenoidWrite(slave3, LOW);
delay(1000);
solenoidWrite(master, LOW);
delay(1000);
}
void solenoidWrite(int pin, bool state)
{
if ( pin >= 0 && pin < 8)
{
if (state)
serialSolenoidOutput |= (1 << pin);
else
serialSolenoidOutput &= ~(1 << pin);
}
digitalWrite(solenoidLatch, LOW);
shiftOut(solenoidData, solenoidClockster, MSBFIRST, serialSolenoidOutput);
digitalWrite(solenoidLatch, HIGH);
}

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August 10, 2018 at 01:39AM by Department of EEE, ADBU: https://ift.tt/2AyIRVT