Solar Agricultural Pump Without Electric Motor
Due to immense irrigation, the water table is depleting. In many parts of the country, the water table has gone down below 800–1000 ft. Multistage and booster pumps are used to pump the water. The conventional variable voltage and frequency submersible motor needs to be designed to pump water from such areas, and they also need capability to withstand the large voltage variation due to the voltage drop in the solar panel. Electrical wiring has to run from the panel outside to the motor inside the well. All these variables result in low efficiency as well as higher capacity solar panel. In addition to this, fine sand, slush, etc., that come along with the water damage the pump. It is a herculean task for a farmer to repair the pump-motor set. Though the government subsidizes the installation of solar pumps, the repair cost has to be borne by the farmer. One side, there is erratic monsoon, and on the other side, cost of maintenance and availability of qualified personals to repair have put the farmers in distress. Today, about 42.3% connected load to the grid is of that of the agricultural pumps. The probability of all pumps not working simultaneously has helped to manage the power demand. To overcome all the deficiency mentioned above, a totally a new concept of pumping the water from deep well as low as 1200 ft without electrical motor with less than 25% of solar panel capacity is discussed in this paper. Once the concept is implemented, the grid can be relieved from the agricultural load, leading to surplus power in the country for the next 20 years.
At the time of this publication PRAPATI has made substantial progress on this project. They have been successful in proving the concept by making a working model. Commercial model of 600 feet pump will be available by end of June 2018.