Fault Current Improved Grey Slope Relational Analysis Based Unit Protection Scheme for DC Distribution Lines

Multi-terminal flexible DC distribution line faults develop rapidly, and power electronic equipment has a poor ability to withstand overcurrent. To solve the aforementioned problem, unit protection scheme based on improved Grey Slope Relational Analysis (GSRA) of fault currents is proposed address issue achieving balance between reliability speed relay for lines. This uses current measured at both ends under various operating conditions, calculates correlation positive negative lines using slope distance polarity increments. Based this, GSRA used analyze signals so that can be eliminated quickly. allows selectivity traditional improved. Simulations PSCAD/EMTDC have shown this method achieve discrimination pole selection by simultaneously measuring line. fast action not affected capacitance converter blocking, strong resistance transition noise interference, reliable identification heavy loads high-resistance ground faults.