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 temperatur e 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 fol lowing 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 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 selfgenerating barrier layer cell is a PV detector that converts radiant flux straight into electrical current[4]. 4
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 cur rent, rent, 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 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, inverters, which are connected to multiple solar modules or panels of the PV the PV system[11]. system[11]. Microinverters have several advantages over conventional inverters. The main advantage is that small amounts of shading, 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 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 a fter 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 datalogger development and the testing and validation of the monitoring system. The datalogger 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 from ambient temperature sensor
Output data from cell temperature sensor
Output data will be implement using Arduino Uno
Output data will be collected by data logger
Data from data logger will send to user PC via online server(Ethernet Shield)
Monitoring the data from online server using GUI
End
Figure 2: Flowchart to get the output data by using Irradiance , ambient temperature and cell temperature sensor
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Start
Output of AC AC current and voltage from solar micro inverter
Output data data from AC current transducer
Output data from AC voltage transducer
Output data will be implement using Arduino Uno
Output data will be collected by data logger
Data from data logger will send to user user PC via via online online server(Ethernet Shield)
Monitoring the data from online server using GUI
End
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) semester)
Activities
Final Year Project 1 September 1
2
3
4
October 1
2
3
November 4
1
2
3
4
December 1
2
3
4
January 1
2
3
4
Meeting with supervisor Title briefing by supervisor Find a journal or other source Proposal writing Proposal submission to supervisor Submit proposal to coordinator
Activities
Final Year Project 2 February 1
2
3
March 4
1
2
3
April 4
Hardware installation Testing and troubleshooting Data collection
Thesis writing
Presentation
Thesis submission
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1
2
3
June 4
1
2
3
July 4
1
2
3
4
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 t o 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 s ystem 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 Grid- Connected Photovoltaic Systems,” pp. 1– 4, 4, 2012.
[2]
A. Rivai and N. A. Rahim, “A lowlow -cost Photovoltaic ( PV ) array Monitoring System,” pp. 169 – 174, 174, 2013.
[3]
“Arduino - ArduinoBoardUno.” [Online]. Available: http://arduino.cc/en/Main/ArduinoBoardUno.. [Accessed: http://arduino.cc/en/Main/ArduinoBoardUno [Access ed: 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. http://www.siemenssol ar.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, 15, 2011.
[6]
D. I. N. Rail, P. Mount, and T. Rms, “True RMS AC Voltage Transducer,” pp. 22– 23. 22– 23.
[7]
S. Cr, “True RMS AC Current Transducer,” pp. 26– 27. 27.
[8]
V. Pro, “Solar Radiation Sensor,” vol. 6450, pp. 1– 2. 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-paneltemperatures. [Accessed: 16-Nov-2014].
[11]
“Solar micro-inverter 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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