EEE Industrial Visit
We visited Dev solar maintained solar power plant at Chevur, Tiruppur on 21.09.2022. We first visited the 1MW solar power plant owned by Sueeraa Alloys. We saw a transformer and inverter room at the entrance. The output from the solar panel is collected through six array boxes and given to inverter through distribution box. Twenty-one solar panels connected in series provide 41 units and are connected to one array box. There are, 3500 solar panels connected in series for a 1MW plant. The array junction box has three wires each of cross-section 4 sq.mm, 16 sq.mm and 95 sq.mm which collects the output in parallel. There are 6 DB boxes. One DB box has a current rating of 250 A. The inverter uses IGBT switch to convert the solar panel DC output into AC for grid integration. The voltage, phase and frequency are synchronized with grid before export.
Explanation about Solar Panels and connections
Next, we went through the solar field and studied about the construction and arrangement of solar panels. The solar panels were made of Silicon semiconductor. Each cell in the panel gives 0.5 V approximately. There are 72 cells in each panel. One panel gives an output power of 40 W (9 A).The solar panels are connected in such a way that a string provides 1000 V. There are total of 4 strings for a 1 MW plant.
The visited solar power plant is on-grid plant. When there is power supply, the output from the solar panel is collected and grid integration is done. Total units imported from the grid is 36 units and export is 5292 units per day.On an average 103648units are exported per month to the grid. Then, we visited the transformer section. The output of the inverter is given to a bidirectional transformer that converts 1000V DC to 440 V AC. The kVA rating of the transformer is 1250 kVA. It is a 33kv/440 V bi-directional transformer, which performs both step up and step-down operation. The ratio of CT is 20/5 A and PT has a ratio of 33kV/110 V with rating of 33 kVA.
Indoor Inverter Room
The Latitude and longitude coordinates of Coimbatore are: 11.004556°, 76.961632°. Based on the location, the solar panels are elevated 11° North South direction so that they receive sunlight for a maximum of 8 hours.
The maintenance of solar panels is easy with less man-power. The solar panels are cleaned daily at 6AM and kept dust free for providing maximum efficiency. The efficiency of the solar power plant is 18-20%. The solar panels have a long lifetime of about 25 years.
Finally, we visited a similar solar field named Adithya Engineers. It has 7000 panels with an outdoor inverter. The rating of Adithya Engineers Solar Power plant is 2 MW with an export of 275664 units per month to the grid.
Details of Journey
A team of 45 students (35+10) and 04 faculty members were visited the Dev Solar Power Plant. Starting from the arrangements of the solar panels in the field and ending with the grid integration, we came to know about the conversion and synchronisation process involved. To ensure that all the students actively involved in the Industrial Visit, they were given a set of 20 questions each, which was answered by them before leaving the plant.
Dev solar maintained solar power plant is located at Chevur, Tiruppur District. With the permission from our transport head, we utilised the college bus for our journey. We departed from our college at 9.45 AM sharp. We had a break for tea and snacks on the way to the power plant. Two solar power plants, Sueera Alloys solar power with a capacity of 1 MW and Adithya Engineers with a capacity of 2 MW were visited. The students were given an introduction about the importance of renewable energy resources and were divided into two batches. They were excited to know about the installation and synchronisation processes involved. Before leaving the plant, our students interacted with the technician person and cleared all their doubts. The students also came to know about the subsidies provided by the government for installing solar panels at houses. We left the Solar field by 2.00pm During return journey, we had our lunch at Avinashi around 2.30 PM and reached college by 4.00 PM.
