Site Visit to Green Electric Energy Park at Curtin University, Perth, Western Australia by Institution of Engineers Sri Lanka Western Australia Chapter In the chilly morning of the Saturday 18 th June 2016, with the temperature hovering around 7 C, about 20 enthusiastic IESLWA members gathered at the Green Electric Energy Park (GEEP) of Curtin University in Bentley, Western Australia as the monthly technical activity organized by the Electrical Engineering subcommittee of IESLWA. Despite the high demand for the visit, the attendance had been limited to 20 due to the space and other limitations of the facility. After getting warmed up with tea, coffee and delicious snacks organized by the Curtin University, the tour party was warmly welcomed by the Director and the Concept Designer of the GEEP laboratory, Dr. Sumedha Rajakaruna, a Senior Lecturer in the Department of Electrical and Computer Engineering. Being a member of the current executive committee of IESLWA, a graduate of University of Moratuwa and also being a lecturer of recently graduated engineers, Dr. Rajakaruna was a familiar face to many who attended. Welcoming the touring party After a brief introduction to the overall facility, the touring party was provided a lengthy guided tour to each of the outdoor renewable energy installations. Due to the rising installation of solar photovoltaic (PV) arrays on rooftops of residential houses, there was a keen interest on the three different types of solar PV arrays on display. The three PV arrays featured the three most commonly used cell types, viz. monocrystalline, polycrystalline and amorphous silicon. All three arrays were on 1-axis trackers tracking the sun's position from East to West, powered and controlled independently. Each of the PV array could be configured into different series/parallel connections to result in suitable voltage/current ratings for the different types of electrical loads applied at the indoor teaching/research stations. The intensity of solar radiation falling on the PV modules and the
backside temperature of the PV modules are measured using sensors mounted to the tracking PV arrays. A bird's eye view of GEEP external installations Keenly interested participants at the Polycrystalline PV array
Many more questions at the amorphous silicon PV array In addition, a full-scale weather monitoring station could be seen atop a 11m tower making realtime measurements of all the important weather parameters such as temperature, wind speed, insolation etc. to correlate with the renewable energy produced by the various sources. On the display were two wind turbines, one horizontal-axis and one vertical-axis on 11m towers with a dedicated anemometer also at 11m height. The down-wind type three-bladed horizontal-axis wind turbine is rated at 2.5kW with blade angle control for power regulation. The 1 kw vertical-axis wind turbine also is of three blade type and used a dump load for power regulation and a short-circuiting breaker to protect the electrical installation from overvoltages during high wind speeds. Both turbines used Permanent Magnet Synchronous Motor (PMSM) generators. At the horizontal axis and vertical axis wind turbines A micro-hydro power station using induction motor as a generator also attracted the attention of many. A variable speed induction motor driven pump simulated the high pressure water of a natural hydro power station. The demonstration made it clear how the power generated could be fed to the grid similar to a grid-connected mini-hydro station and also how the regulated power can be supplied to a small rural community such as in a stand-alone micro-hydro station. The flow, pressure
of water, speed of the turbine are all made available both through analog meters at the site as well as digitally on the computer network. At the micro hydro and solar water pumping station Another interesting feature of the lab was the hydrogen based power generating station. The 1.2kW Proton Exchange Membrane (PEM) fuel cell stack combines pure hydrogen with oxygen in air to produce electricity, heat and water. The supply of hydrogen can be through the feed from an onsite electrolyser decomposing water into hydrogen and oxygen or from commercial hydrogen stored in small metal hydride canisters. The power generated can be used to feed directly to the grid or to form a regulated stand-alone dc or ac power supply using dc/dc converter and dc/ac inverter. A programmable 3-phase, 400V, 9.1kW resistive load bank that can simulate the load profile of any real load and the 48V, 320Ah lead-acid battery bank were the other external facilities. These two pieces of equipment were later demonstrated as key to forming a stand-alone microgrid. The electrolyser, PEM fuel cell stack and metal hydride canisters
Having learnt about all the external installations, the tour group was then given a detailed description and demonstration of how the renewable energy generated is used for teaching and research purposes at the 7 teaching stations and 4 research stations inside the GEEP building. At the three teaching stations dedicated for each solar PV array, it was shown how the grid-feeding of solar energy is made, how the batteries can be charged through solar charge controllers, how such batteries can then be used to form an island power supply, how the characteristics of solar PV modules can be measured electrically under different operating conditions. At the wind power teaching stations it was demonstrated how the variable frequency, variable voltage ac is first rectified and then converted to grid frequency ac for grid-connection. GEEP teaching stations Demonstration of teaching stations The final demonstration was how a stand-alone ac microgrid can be formed using battery backup and inverters. The 3x1-phase, 230V, 5kW back up inverters worked in a master-slave arrangement to
form the 3-phase ac supply to the programmable load and to receive power from the renewable energy sources and to charge/discharge the battery bank. The demonstration showed the steadystate at each mode of operation and transients during islanding and grid-resynchronization. The power system was thus shown to be operated as either grid-connected or islanded. Three single-phase microgrid-forming back up inverters and switchboard at the middle of the photo. The most attractive feature of the laboratory was its user friendly design with all digital measurements and custom made software. The workstation computers displayed each teaching station graphically with real-time updating power and weather data. Students could view the variations of selected electrical or weather parameters on the monitor at different time/frequency scales, retrieve historical data over many years, save data on Excel files or log real-time data by the click of a button for the preparation of lab reports. The whole laboratory was designed in a paperless approach with data recording, analysis, report preparation, submission, grading and feedback all made in a digital domain. Furthermore, the GEEP real-time data can be accessed remotely over the internet. Using this facility and high precision cameras and microphones installed, laboratory classes can be delivered to remote overseas campuses. It was reported that the regular lab classes were delivered in this manner in the last two years to Sri Lanka Institute of Information Technology (SLIIT) at Malabe, Sri Lanka demonstrating its effectiveness. The participants were of high praise to Dr. Rajakaruna and to the IESL WA Chapter for providing such a rare opportunity to visit a unique state of the art laboratory in renewable energy.