DC power distribution network double-end distance measurement fault positioning method based on improved injection method

Abstract

The invention provides a DC power distribution network double-end distance measurement fault positioning method based on an improved injection method. Two ends of a DC power distribution network are both provided with respective fault distance measurement module. The fault distance measurement module comprises a capacitor, an inductor and an SP3T switch. By adjusting sizes of the capacitor and theinductor, the fault distance measurement module and a fault line are made to form a two-order RLC discharging circuit of under damping oscillation. Nonlinear least square fitting is utilized to determine oscillation frequency of discharging current attenuation and an attenuation coefficient. By introducing double-end information amount, a fault distance measurement algorithm in a traditional injection method is improved, thereby obtaining a fault distance calculation formula with a total line length, inductance and capacitance values of the fault distance measurement module as the parametersand removing effect of DC line inductance and resistance on fault positioning. The fault distance measurement module of the invention can realize repeated measurement and avoid an occasional situationand further replace line resistance and inductance with the total line length. With concise principles, the DC power distribution network double-end distance measurement fault positioning method based on an improved injection method greatly improves reliability and accuracy of distance measurement.

Description

technical field [0001] The invention relates to the technical field of fault distance measurement of a DC distribution network, in particular to a fault location method for double-terminal distance measurement of a DC distribution network based on an improved injection method. Background technique [0002] At present, energy and environmental problems are becoming more and more prominent. Clean distributed power generation methods such as photovoltaic power generation and wind power generation have become very important research contents because of their clean, economical and flexible characteristics. However, distributed Intermittent and fluctuating power supply will affect the stability of the traditional AC power grid. In addition, the disadvantages of the traditional AC distribution network have gradually emerged. For example, the capacity margin of the AC line cannot meet the growing demand for electricity; the increase in DC equipment has resulted in the use of AC-DC c...

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