1.0 ABSTRACT

Photovoltaic (PV) generation, as one of renewable energy generation, will play an

importance role to solve the energy shortage and environmental problem in the future.

Electricity produced by PV systems has been increasing worldwide due to its more

progressive insertion into governmental policies aiming to find more renewable energy

sources[1].

A Grid-Connected Photovoltaic (GCPV) system typically consists of several

Photovoltaic (PV) modules which are connected to one or more than one inverters. The

PV modules firstly convert the sunlight into DC electricity. The DC electricity is later

converted into AC electricity which matches the grid electricity characteristics via an

inverter. The GCPV systems have become primarily significant especially in urban areas

where the conventional utility grid is readily available for interconnection. If the system

fails to meet the load demand due to poor weather performance, the load demand is often

met by the grid. Thus, the operation of GCPV system as one of the alternative modes of

electricity generation appears to be practical. However, the implementation of these

systems can only be technically and economically feasible if the systems are operating as

what has been designed.

Therefore, this study is aimed to monitor and provided the data to the user to simulate

the system performance of GCPV that has become the primary concern. It is because this

monitoring system is important to maintain a PV system’s sustained operability, and for a

user to understand glitches that occur while system is operating. In developing the PV

system, information of photovoltaic characteristics is essential as well as the information

on meteorological. Many monitoring systems have been developed in order to evaluate PV

system performance. Several instruments using conventional electronics or based on

microprocessor data- acquisition system (DAQS) are developed. It is used to collect,

register, integrate and record meteorological data and also the electrical characteristic of

PV system[2].

There are several types of sensor that must be used to monitor the system performance

of the GCPV. The types of sensor are the solar irradiance, ambient temperature, and solar

cell temperature, AC voltage and AC current transducers.

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2.0 INTRODUCTION

2.1 Overview of study

In existing monitoring of Grid-Connected Photovoltaic (GCPV) systems, the under-

performance of a GCPV system remains not detected until an analysis and evaluation of

system performance are performed at a specific interval throughout the monitoring effort.

Therefore, this study has provided the PV monitoring system using an Arduino-based

microcontroller.

The proposed monitoring system consists of a data acquisition system containing

sensors for measuring solar irradiance, ambient temperature and solar cell temperature. All

sensors in this system connect to Arduino based microcontroller. Ethernet shield is used to

send the data from the Arduino to the user. Then the user can view the data by using

Graphical User Interface (GUI).

In this system also the AC voltage and AC current transducer is used to measure the

values of the voltage and current respectively. These measurements also use Arduino to

implement the data from both transducers. The both transducers are also connected to the

data-logger where user can record and monitor the data.

2.2 Problem statement

The output performance of a GCPV system has usually fluctuated as it is strongly

dependent on the varying ambient parameters such as solar irradiance and temperature. As

a result, GCPV system performance are often monitored by logging the system input

parameters such as solar irradiance, ambient temperature and solar cell temperature as well

as the output power from the inverter. The system performance is then analyzed and

evaluated periodically using the monitored data to determine the overall system

performance indicators. Therefore, a system is diagnosed to have good or poor

performance only after the evaluation is made at the end of the monitoring period, i.e.,

commonly at the end of each month or at the end of the year.

However, a major drawback of such monitoring mechanism is the occurrence of fault

cannot be detected immediately unless the performance of the system is evaluated

continuously throughout the monitoring.

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2.3 Significant of work

For this system the data from all sensors will be record by using data logger then the

data will be sent to user by using Ethernet shield of Arduino. This system is to provide the

data that to be simulated by user to differentiate the error between the predicted power

and the actual power from the system that will be used as the accuracy indicator for the

prediction. The proposed monitoring system will enable an immediate detection of poor

system performance, thus allowing the corrective maintenance to be conducted

immediately without relying on the periodic maintenance or the periodic evaluation of the

system performance.

2.4 Objectives

This study proposes a continuous PV monitoring system using an Arduino-based

microcontroller. The study is aimed to fulfill the following objectives:

1) To develop low cost data recorder and monitoring the performance of the GCPV

system

2) To predict the output power from a GCPV system

3) To detect under-performance of a GCPV system

2.5 Scope of work

In this study, this monitoring system is to provide the data from the sensors that is

developed as a separate unit from the GCPV system. It comprises a data-logger that

displays the data using Graphical User Interface (GUI). The data logger will be used for

converting the analog inputs from the various sensors to digital inputs that are

recognizable by the data-processing software. The data-logger will receive the data from

the solar irradiance, ambient temperature and cell temperature as its inputs while the AC

power from the GCPV system will be set as its output. It will be utilized as a predictor of

the expected AC power from the GCPV system based on the instantaneous solar

irradiance, ambient temperature and cell temperature. If the actual power from the GCPV

system is lower than the expected power a fault indicator in the software will be activated.

Thus, the corrective action could be done immediately without waiting for the periodic

evaluation of the system performance.

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The AC voltage and AC current transducers also was used in this system to measure

the values of the voltage and current respectively. These both transducers are connected to

output of the inverter. These measurements also use Arduino to implement the data from

both transducers. The both transducers also connected to the data-logger where user can

record and monitor the data. This data will send to the user using Ethernet shield that are

compatible with Arduino. When user has the data user can differentiate the error between

the predicted power and the actual power from the system that will be used as the accuracy

indicator for the prediction.

2.6 Literature review

The hardware that must use in this PV monitoring system using an Arduino-based microcontroller is state below:

2.6.1 Arduino Uno microcontroller

For this project, Arduino Uno is the main focused because it is a technology selection

for this system. The Arduino Uno is a Microcontroller board based on the ATmega328.

Arduino Uno has 14 digital input and output pins which is 6 pins can be used as PWM

outputs, 6 analog inputs, a 16MHz crystal oscillator, a USB connection, a power jack, an

ICSP header, and a reset button. It contains everything needed to support the

microcontroller, just connect it to a computer with a USB cable or power it with a AC to

DC adapter or battery to get started. The UNO differs from all preceding boards in that it

does not use the FTDI USB to serial driver chip[3].

2.6.2 Solar Panel

A solar panel simply put is a collection of solar cells. They work together to supply

electricity for various uses. A single cell does not have the capacity for generating a lot of

electricity so multiple cells are connected together to increase the capacity, how many

cells depends on the amount of electricity required. The more light available to the solar

panels the greater the amount of electricity they can supply.Solar panels are designed to

convert light into electricity[4].

The process of extracting electricity from light is called Photovoltaic (PV) and the PV

process converts solar energy directly into electricity. A PV cell, also known as a self-

generating barrier layer cell is a PV detector that converts radiant flux straight into

electrical current[4].

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2.6.3 Data logger

The data logger is an electronic device that records data over time or in relation to

location with a built in sensor. One of the primary benefits of using data loggers is the

ability to automatically collect data on a 24-hour basis, and time stamp of logging can be

set (five minutes to one hour basis). Upon activation, data logger is left unattended to

measure and record information for the duration of the monitoring period. This allows for

a comprehensive, accurate picture of sub-system conditions being monitored, such as PV

Solar Cell, Battery, Charger/Controller, LED Lamp and ambient temperature [5].

2.6.4 AC Voltage Transducer (CR4500 Series)

The CR4500 Series, true RMS Voltage Transducers and Transmitters are designed for

applications where AC voltage waveforms are not purely sinusoidal. More precise and

accurate than other devices, these units are ideal in chopped wave and phase fired control

systems[6].The applications of this AC Voltage Transducer is Phase fired controlled

devices, Quickly varying voltage supplies, Chopped waveform drivers and Harmonic

voltages[6].

Features of AC Voltage Transducer:

35mm DIN rail mount or panel mount

Available with 0-5 Vdc or 4-20 mA DC outputs

24 Vdc powered

Highest precision available

Outputs isolated from inputs

Connection diagram printed on case

2.6.5 AC Current Transducer (CR4100 Series)

The CR4100 Series True RMS Current Transducers and Transmitters are designed for

applications where AC current waveforms are not purely sinusoidal. More precise and

accurate than other transducers, these devices are ideal in chopped wave and phase fired

control systems[7]. The applications of this AC Current Transducer (CR4100 Series) is

Phase fired controlled heaters, Quickly varying motor loads Chopped wave form drivers

Harmonic currents[7].

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Features of AC Current Transducer:

35mm DIN Rail or Panel Mount

Available with 0 - 5 VDC or 4 - 20 mADC outputs

24 VDC powered

Use with external current transformers

Highest precision available

Connection diagram printed on case

2.6.6 Irradiance Sensor

The Solar Radiation Sensor, or solar pyrometer, is to measures global radiation, the

sum at the point of measurement of both the direct and diffuse components of solar

irradiance. The sensor’s transducer, which converts incident radiation to electrical current,

is a silicon photodiode with wide spectral response. From the sensor’s output voltage, the

console calculates and displays solar irradiance. It also integrates the irradiance values and

displays total incident energy over a set period of time[8].

It delivers a reference value for solar radiation and enables conclusions to be drawn

about possible power generation problems. The irradiance sensor consists of a single solar

cell and should be installed at the same angle as solar panels. This helps it to serve as an

ideal reference value. Drops in performance even at low levels of radiation can be

identified and error messages generated. Due to the built-in internal module temperature

sensor, it is easy to analyze reductions in performance[9].

2.6.7 Cell Temperature Sensor

The cell temperature sensor is used to measure the temperature in solar system. It has

been shown that the temperature of a solar panel directly affects its maximum power

output. The flat surface temperature sensors can be mounted on each solar panel or on

selected representative solar panels to provide temperature measurement profiles of a solar

panel array[10].

The sensor can provide temperature measurement data to an overall monitoring

system, allowing for advanced notification of potential power output issues caused by

changes in the solar panel’s temperature. With this measurement information, adjustments

can be made to the power delivery system or the whole power grid if necessary[10].

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2.6.8 Solar Micro-Inverter

A solar micro-inverter, or simply microinverter, is a device used in photovoltaics that

converts direct current (DC) generated by a single solar module to alternating current

(AC). The output from several microinverters is combined and often fed to the electrical

grid. Microinverters contrast with conventional string and central solar inverters, which

are connected to multiple solar modules or panels of the PV system[11].

Microinverters have several advantages over conventional inverters. The main

advantage is that small amounts of shading, debris or snow lines on any one solar module,

or even a complete module failure, do not disproportionately reduce the output of the

entire array[11].

2.6.9 Ethernet Shield

The Arduino Ethernet Shield allows an Arduino board to connect to the internet. It is

based on the Wiznet W5100 ethernet chip. The Wiznet W5100 provides a network (IP)

stack capable of both TCP and UDP. It supports up to four simultaneous socket

connections. Use the Ethernet library to write sketches which connect to the internet using

the shield. The ethernet shield connects to an Arduino board using long wire-wrap headers

which extend through the shield. This keeps the pin layout intact and allows another shield

to be stacked on top. The most recent revision of the board exposes the 1.0 pinout on rev 3

of the Arduino UNO board[12].

The Ethernet Shield has a standard RJ-45 connection, with an integrated line

transformer and Power over Ethernet enabled. There is an onboard micro-SD card slot,

which can be used to store files for serving over the network. It is compatible with the

Arduino Uno and Mega (using the Ethernet library). The onboard microSD card reader is

accessible through the SD Library. When working with this library, SS is on Pin 4. The

original revision of the shield contained a full-size SD card slot; this is not supported[12].

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The shield also includes a reset controller, to ensure that the W5100 Ethernet module

is properly reset on power-up. Previous revisions of the shield were not compatible with

the Mega and need to be manually reset after power-up[12].

The current shield has a Power over Ethernet (PoE) module designed to extract power

from a conventional twisted pair Category 5 Ethernet cable[12]:

IEEE802.3af compliant

Low output ripple and noise (100mVpp)

Input voltage range 36V to 57V

Overload and short-circuit protection

9V Output

High efficiency DC/DC converter: typ 75% @ 50% load

1500V isolation (input to output)

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3.0 METHODOLOGY

The proposed monitoring system will be developed in several stages, i.e. the data-

logger development and the testing and validation of the monitoring system. The data-

logger will be developed using Arduino microcontroller to suit the sensor characteristics

and interfacing solutions for sensing and signal conversion from the sensors to the

software in a PC that was Illustrated as figure 1. Five sensors will be used for collecting

the solar irradiance, ambient temperature, solar cell temperature. The way to collect the

data from those sensor is shown in Figure 2. AC voltage and AC current transducers from

the output of the inverter also was used to collect the AC current and AC voltage data. The

way to collect those data is shown in figure 3 .The AC voltage and AC current values will

be used to calculate the measured AC power from the system.

Signal from each sensor will be collected by a data-logger for scaling and analog to

digital conversion. The signals will be then send the data to the user which contains the

user-friendly features of Graphical User Interface (GUI). A prediction error will be used to

quantify the prediction performance. If the prediction error is larger than a preset error, a

fault error message will be displayed by the software to warn the GCPV system owner.

Thus, the corrective maintenance could be performed immediately without waiting for the

common periodic evaluation of system performance. Testing and validation of the

monitoring system will be conducted using a different set of data which will be obtained

using the same GCPV system under study.

However, several fault conditions will be simulated by shading one PV module in one

of the PV strings in the system such that a low power output is obtained. Thus, this

performance monitoring system is expected to detect the fault condition and warn the

system owner about the poor performance of the system.

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Figure 1: Illustration of an intelligent-based monitoring system for a GCPV system

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Start

Output data from irradiance sensor

Output data will be collected by data logger

Output data from cell temperature sensor

Output data from ambient temperature sensor

Data from data logger will send to user PC via online

server(Ethernet Shield)

Monitoring the data from online server using GUI

End

Output data will be implement using Arduino

Uno

Figure 2: Flowchart to get the output data by using Irradiance , ambient temperature and cell temperature sensor

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Start

Output data will be collected by data logger

Output data from AC current transducer

Data from data logger will send to user PC via online

server(Ethernet Shield)

Monitoring the data from online server using GUI

End

Output data will be implement using Arduino Uno

Output data from AC voltage transducer

Output of AC current and voltage from solar micro

inverter

Figure 3: Flowchart to get the output data by using AC current and AC voltage transducers

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4.0 PLAN SCHEDULES (Gantt chart for both semester)

Activities Final Year Project 1

September October November December January

1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4

Meeting with supervisor

Title briefing by supervisor

Find a journal or other source

Proposal writing

Proposal submission to supervisorSubmit proposal to coordinator

Activities Final Year Project 2

February March April June July

1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4

Hardware installation

Testing and troubleshooting

Data collection

Thesis writing

Presentation

Thesis submission

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5.0 EXPECTED RESULTS

The expected result for this PV monitoring system using an Arduino-based

microcontroller based on the output of the sensors and tranducers. The performance of this

system depends on logging the system input parameters such as solar irradiance, ambient

temperature and solar cell temperature as well as the output power (AC current and AC

voltage) from the inverter. The system performance is will be analyzed and evaluated

periodically using the monitored data to determine the overall system performance

indicators.

The data of the system were collected in a specific day. The performance

monitoring and test system can show the every collected real time data in curves or in

table list on the screen of the PV.

6.0 CONCLUSION

The conclusion that can be made from this PV monitoring system using an

Arduino-based microcontroller, user can produce low cost PV monitoring system to get

the performance data based on sensors and transducer that can be implemented using

Arduino Uno. Therefore user can immediate detect the poor system performance, thus

allowing the corrective maintenance to be conducted immediately without relying on the

periodic maintenance or the periodic evaluation of the system performance.

The aim of this system is to provide the performance data to user by using Ethernet

shield of arduino which can make recording and monitoring works become easily to user

to predict the output performance of PV monitoring system. Then user can accessed the

performance data at any places that have internet connection. This system also create user

friendly Graphical User Interface (GUI).

Last but not least this system will make the renewable energy generation more

effectively and will help people consume electricity without any problem. It is because

renewable energy can help us to safe our world become more greenly.

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7.0 References

[1] X. Zou, L. Bian, Z. Yonghui, L. Haitao, A. Description, and G. Pv, “Performance Monitoring and test System for Grid-Connected Photovoltaic Systems,” pp. 1–4, 2012.

[2] A. Rivai and N. A. Rahim, “A low-cost Photovoltaic ( PV ) array Monitoring System,” pp. 169–174, 2013.

[3] “Arduino - ArduinoBoardUno.” [Online]. Available: http://arduino.cc/en/Main/ArduinoBoardUno. [Accessed: 16-Nov-2014].

[4] “Solar Panels - Information and facts on solar panels, home solar panels, solar panel info.” [Online]. Available: http://www.siemenssolar.com/solar-panels.html. [Accessed: 16-Nov-2014].

[5] A. Purwadi, Y. Haroen, F. Y. Ali, N. Heryana, D. Nurafiat, and A. Assegaf, “Prototype Development of a Low Cost Data Logger for PV Based LED Street Lighting System,” no. July, pp. 11–15, 2011.

[6] D. I. N. Rail, P. Mount, and T. Rms, “True RMS AC Voltage Transducer,” pp. 22–23.

[7] S. Cr, “True RMS AC Current Transducer,” pp. 26–27.

[8] V. Pro, “Solar Radiation Sensor,” vol. 6450, pp. 1–2.

[9] S. Box, “Inverter connection and sensors Pyranometer and Irradiance Sensors with Module Temperature Sensor.”

[10] “Sensor Monitors Solar Panel Temperatures.” [Online]. Available: http://www.rdmag.com/product-releases/2011/06/sensor-monitors-solar-panel-temperatures. [Accessed: 16-Nov-2014].

[11] “Solar micro-inverter - Wikipedia, the free encyclopedia.” [Online]. Available: http://en.wikipedia.org/wiki/Solar_micro-inverter. [Accessed: 16-Nov-2014].

[12] “Arduino - ArduinoEthernetShield.” [Online]. Available: http://arduino.cc/en/Main/ArduinoEthernetShield. [Accessed: 16-Nov-2014].

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