SABI Magazine August September 2016 V 7 | Page 22

Variable Speed Drives Grid Tied Solar Assist Pump Motor Control Solutions by Irri-Gator Products I rri-Gator Products is well known to the industry as an innovative, dynamic and forward thinking company that specializes in irrigation system automation and controls. During early 2016 Irri-Gator was approached by Ren Energy to provide input on the design and supply of a Solar Photovoltaic (PV) pump control system for Just Trees, located between Paarl and Wellington in the Western Cape. Each of the companies are specialists in their respective fields with Ren Energy specializing in engineered Solar PV solutions while Irri-Gator 20 specializes in advanced motor control applications. This joint venture made perfect synergy as an optimal design solution was presented to the client, approved, successfully installed and commissioned in early June 2016. Background The farm makes use of 2 separate irrigation systems. System one SABI | AUGUST/SEPTEMBER 2016 makes use of 2 x 22kW pumps that operate in parallel. The second system makes use of a single 30kW pump. Although unlikely, it is a possibility that the two systems operating simultaneously could absorb up to 74kW of power at peak utilization. The project’s main objective was to optimize the utilization of power and be less reliant on power from the Eskom grid, to attain maximum savings. The irrigation system on the farm is unconventional as they are “farming” an unusual “crop”. Just Trees is a wholesale nursery growing and supplying large trees in bags (40 – 1 000 litre bags) for the landscape industry. The bags are filled with a growing medium which does not have much of a water holding capacity. The irrigation water is enriched with fertiliser and supplied to each container via the dripper irrigation network. With batches of trees being removed from the growing plots, as and when they are sold, irrigation lines are isolated which causes a constant variance in flowrates within the irrigation system therefore affecting the hydraulics and making this a difficult system to manage while trying to achieve