Inverter-based new energy power source symmetrical fault analysis method considering control switching delay

Abstract

The inverter type new energy power source symmetry fault analysis method considering control switching delay belongs to the new energy power system relay protection technical field, solves the problem of low accuracy of inverter fault transient current analysis model; The drop amplitude of grid-connected point voltage is measured based on dq coordinate transformation; Considering the control switching delay caused by voltage detection link, the fault transient process is finely divided into two stages with LVRT control input as the time division point; In the first stage of fault transient, LVRT control is not put into operation, the response of current inner loop is ignored based on outer loop voltage control equation, and the fault current model is established combined with power balance equation; In the second stage of fault transient, the outer loop is locked and switched to LVRT control, and the fault current analytical expression is solved by simultaneously solving the inner loop control equation and the physical topology equation; Finally, the fault current analytical model of the whole fault process is established; The calculation can improve the analysis accuracy, and the accurate analysis of the fault transient current is realized.

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