The invention discloses a flexible grounding device single-phase grounding fault line selection and arc extinguishing method for a power distribution network. The method mainly comprises the steps: employing a virtual
resistor control mode when a single-phase grounding fault happens to the power distribution network, controlling a flexible grounding device to inject a resistive current with the controllable amplitude value into a neutral point, enabling a
system to operate in a small-resistance grounding mode, and judging a fault
feed line through the measurement and comparison of the zero sequence currents of all feed lines, and giving the feedback to a
relay protection device; employing a virtual
inductance control method, controlling the flexible grounding device to inject an arc-extinguishing compensation current into the neutral point, enabling the
system to operate in a resonant grounding mode, and achieving a purpose of single-phase grounding fault arc extinguishing. Through the switching of control
modes, the method can solve problems that a resonant grounding
system cannot accurately judge the fault
feed line, a small-resistance grounding system is high in fault trip-out rate and a fault of a conventional flexible grounding device control method is difficult to detect during high-resistance grounding. The method can reduce the maloperation rate of protection, improves the fault arc extinguishing success rate, and improves the power supply reliability of the power distribution network.