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An Investigation into Installing a Solar Intermittency Monitoring System at Murdoch University: A Proposed Design for the Installation of a System at Building 190

By Melissa Sharpe


This project investigated installing a solar intermittency monitoring system at Murdoch University (MU). Solar energy is defined as an intermittent source due to its varied, uncontrollable nature in standard operational conditions, in comparison to conventional power supply systems sourced from fossil fuels. Cloud cover, time of day, and solar seasonal variance are factors which affect solar energy production. Solar intermittency research and collection of data is essential to Australia’s continued integration of renewable generation and progress towards a clean energy future. The two key parameters required to monitor solar intermittency are global horizontal irradiance (GHI) and DC output power. Additional parameters to be measured for this study were: wind speed, wind direction, ambient temperature, module temperatures, humidity, DC output voltages, DC output currents, and AC power to the utility grid. Solar intermittency monitoring also requires a fast sample rate, which was chosen as 1 second (s) for this project, and a high sensor accuracy of 5% for GHI and 2% for power measurements. With this in consideration PV systems on MU Library, and Building 190 were investigated and analysed to determine the best location to install the system. The Engineering and Energy Building PV Array monitoring system was examined as Mael Riou had proposed a solar intermittency monitoring structure there in his thesis in 2012. MU Library was dismissed as the installation site as the present sensors which monitored current, voltage, power, and solar irradiance had a higher inaccuracy than recommended by the International Standards IEC 61724, and an averaged data sample rate of five minutes. This would require a complete overhaul of the current monitoring system which would have been significantly beyond any budgetary considerations. Building 190’s PV monitoring system therefore became the focus of the project and required two new solar irradiance sensors and a replacement device for a National Instruments (NI) FieldPoint (FP)-TC-120, 8-Channel Thermocouple Module. Considerable problems were discovered upon further investigations into Building 190 including: communicating with the PLC which prevented power from flowing to the PV inverter without removing safety features of the system, the Sunny Boy 5000TL inverter having a device fault once power was restored to it, preventing AC power to the utility grid from being monitored as it was not flowing, and the removal of access to the roof, where the PV array and majority of monitoring equipment is located, in Week 11 of semester. The Renewable Energy Power System (REPS) Training Facility was suggested as a potential site to design and install a solar intermittency monitoring system after this. The PV array there was fully functional. However upon further investigation it was determined the FP Modules, which communicated data about meteorological parameters, were not connected. While this issue could be resolved, the limited time and the scope of work required rendered it unsuitable for this project. Focus was then returned to Building 190 where a NI LabVIEW project was developed to monitor and log the parameters. The SP Lite2 Silicon Pyranometer was selected as the solar irradiance sensor. However installation of the device did not occur due to budgetary, manpower, and, time restrictions. A proposed design was suggested to replace the NI FP-TC-120 with a NI Compact FieldPoint (cFP)-TC-125. However due to the age of the current equipment and their obsolete statuses, any upgrade of the FP modules would require a new NI Data Acquisition (DAQ) system to be bought and installed. The “Solar Intermittency” LabVIEW VI attained measurements with a somewhat questionable validity. Signal noise was quite noticeable in the voltage, and current measurements due to the 500Hz filter frequency required by the FP-AI-110 unit to meet the 1 second sample rate. Ideally both FP-AI-110 modules, which monitored the voltage, current, and meteorological parameters would be replaced with either a NI cFP-AI-112 or cFP-AI-118 which are both capable of sampling at a 1 second rate with lower filter frequencies. The Parallel Block D Current’s Dataforth was also revealed to be malfunctioning and needed replacement. To install a solar intermittency monitoring system at Building 190 a large budget of approximately $6,300 would be required as well as work to be performed to fix the significant problems which currently exist at the location. Overall, it was not possible to install a solar intermittency monitoring system at MU during this time. Although the objective of the project to install a solar intermittency monitoring system at MU was not achieved, some positive outcomes were produced including: •Identification of solar intermittency monitoring parameters, and specifications about solar intermittency monitoring prerequisites such as sample rate, equipment, measurements, and sensor accuracy. •An extensive evaluation of the PV systems and their associated monitoring structures and equipment at MU’s South Street Campus. •An in-depth examination and documentation of Building 190’s PV array and associated monitoring system, including problems and solutions to these experienced during the review. •The development of a LabVIEW program for Building 190’s solar intermittency monitoring system to detect and record the necessary parameters, as well as a detailed proposal and recommendations to upgrade the solar monitoring system currently at Building 190

Year: 2013
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Provided by: Research Repository
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