Experimental study on harmonic mitigation in a grid connected solar power plant

With the decrease in fossil fuel and the increasing threat of climate change, renewable sources of energy like solar energy are a very logical and sustainable choice for everincreasing energy demand. Solar energy is converted into electrical energy through the use of solar power plants. These plants contain a photovoltaic array, maximum power point tracking device, a DC to DC converter and generally a multilevel inverter. Due to such extensive use of power electronic devices which generally have unknown linear voltage-current characteristics, harmonics in these kinds of systems are a very real problem. To mitigate this problem power filters are utilized. There are basically two kinds of filters namely active and passive power filters, passive power filters usually provide less impedance Path to the ground for harmonic frequency currents however active power filters mitigate harmonics by injecting active power with the same frequency but with reverse phase. The problem with active power filters is that they add cost to an already expensive solar Power plant that is why there is a need for a comparative study between active power filters and passive power filters to keep the cost low and performance as optimum. This study is an effort towards achieving the above-mentioned goal. Here Simulink model office solar Power plant with two nonlinear loads on the grid side have been studied with active as well as passive filters and it is therefore concluded that for a given harmonic frequency the count of which should be less than two and dc component or zero frequency component are absent in the given waveform passive har- monic filters are a cheap and robust option, similarly for a given waveform of current or voltage if the harmonic frequencies present in them have a count more than two and/or contains dc component or zero frequency component of harmonic active power filter are better in terms of performance.