Nowadays, the renewable energy resources are taking a leading role. One of them is solar, from the past few years the industries, hospitals, educational institutions and shopping malls depends on the diesel generator set as an auxiliary supply. In case of power failure, these diesel engine drive generator set are not economical as the cost of fuel, maintenance and efficiency considerations made them to be worst and later on some of the industries adopted the emerging technology the solar to

more »

... a compensation of all these factors. At present, all the consumers irrespective of loads have adopted the solar panels. The solar panels works efficiently only during day light time and it cannot deliver power on a cloudy or rainy day as that on a sunny day. So, the solar panels are chosen to deliver at day time and the remaining time the load is energized by the grid. Such that the load utilizes solar and at times by delivering it to the grid too. It is fine but the major problem arises here while utilizing this solar power to the confined loads through the same bus which is also fed from the grids. When there is excess generation of power through panels, it send back to the grid and at low power generation during rainy and cloudy days the loads are powered with the grids. This paper helps in protecting the load when there is no sufficient power supplied from solar panels. The load is altered between solar and grid connected modes based on the incoming voltage levels. This operation is carried out using a DPDT relay by an Arduino control scheme. It is used in general-purpose switching and amplification BC847/BC547 series 45 V, 100 mA NPN general- purpose transistors. They are often used to interface an electronic circuit, which works at a low voltage to an electrical circuit which works at a high voltage.