Research on a novel hybrid power flow controller protection based on zero sequence measurement impedance amplitude and phase characteristics

For the uneven distribution of current in the grid, line overload problem, can use the hybrid power flow controller (HPFC) to achieve the control of line current. In this paper, a new hybrid current controller protection problem in electric energy system is investigated, and a longitudinal principle of vertical connection protection based on the amplitude-phase characteristic of zero-sequence measurement impedance is proposed. The protection principle makes use of the phase and width characteristics of the change in zero sequence voltage and the change in zero sequence current measured at the power and load sides when a grounding asymmetry fault occurs in the new hybrid current controller to form a protection criterion, which can effectively judge the grounding asymmetry fault in the area. This article provides a theoretical analysis of this principle and builds a simulation model in PSCAD for emulation to verify. The consequences suggest that the algorithmic criteria for this protection principle are simple and straightforward, with high sensitivity and reliability. It also addresses the following issues of protection rejection when conventional differential protection is short circuited by large transition resistance. The research content of this article has important implications for the practical application of a new hybrid power flow controller in the power grid.