Influence of Different New Energy Penetration Rates on Distance Protection

The integration of new energy into power grid brings a series of problems to relay protection. The influence of system impedance ratio (SIR) on distance protection was introduced firstly. Then grid simulation models integrated with photovoltaic and wind power respectively were built. Based on simulation results, the characteristics of system impedance ratio under different penetration rates of new energy were analyzed. It is pointed out that the system impedance ratio increases gradually with the increase of new energy penetration rate. Then the action performances of distance protection under different new energy penetration rates were studied. It is found that under a fixed capacitor voltage transformer (CVT) error, when the new energy penetration rate is greater than a certain value, the line distance protection will have an overreach. Some countermeasures were also put forward in the paper.