Question

Define appropriate fault detection and protection system in a PV system (mini grid)

Answer 1

Installation of solar cells across the world has been rapidly increasing as it is renewable energy source and recent record shows its efficiency close to 43%.For a good pv system it should be resistive against faults and abnormal conditions like surges,lightning etc. Fault detection in pv system: I would like to mention one of method as it is more appropriate. A practical fault detection approach for pv systems intended for online implementation has been developed.Here model is developed using artificial neural network.firstly pv system is simulated using MATLAB software and output power is collected for various combinationsof irradiance and temperature.Data is first collected for normal operating condition and then 4 faults are simulated.Line to linr faults with small voltage difference,degradation and open circuit faults.This data used to train neural network and to develop fault detection model.This system is generalised on any pv module datasheet can be used to simulate pv system. Protection system in pv system: Main protection needed in pv system is for surge protection and lightning protection,lets discuss brief about that.As its very nature,photovoltaic(pv) arrays are generally constructed in large open areas where system is highly susceptible to lightning strike.so they should designed to be safe from the effect of lightning.Lightning protection systems(LPS) provides protection zone to assure direct strikes by utilizing basic principals of air terminals,down conductors,equipottential bonding,seperation distance and low impedence grounding electrode system.Single air terminal offers a cone protection based on heightof air terminal,Using a rolling-sphere model for lightning protection,several air terminals create zones of protection.Equipment below the arc between tips of air-terminals is considerd to be protected. Surge protection devices(SPDs) may be used as secondary measure of protection when installed in conjunction with LPS,SPDs also used as primary measure of protectionif cost of installing air termination system cannot be economically justified.SPDs mainly used to clamping the voltage,thereby minimizing transient voltages,they also prevent pv systems from lightning damage.

I hope this will help you.