Analysing the feature of instantaneous positive sequence network when single-phase grounding in resonant grounding system

Establishing the mathematical model of instantaneous positive sequence network of power source, grounding petersen coil, ground point, capacitance to the ground to the 10 kV medium-voltage resonance grounding system with instantaneous symmetrical component, establishing the mathematical model of instantaneous positive sequence network to resonance grounding system. The mathematical expression of instantaneous positive sequence current real part and imaginary part in fault branch and unfault branch is derived from this model. Obtaining the feature of instantaneous positive sequence network: steady state after fault, the phase of instantaneous positive sequence current real part in fault branch lags behind unfault branch with a angle, but all unfault branches´ phase is almost equal; the amplitude of instantaneous positive sequence current real part in fault branch is smaller than the time before fault. The simulation verifies the theoretical analysis.