RL model algorithm based fault ranging method of DC power distribution network

Abstract

The invention provides an RL model algorithm based fault ranging method of a DC power distribution network. The method comprises the steps: a line equivalent R-L model is established for a bipolar short-circuit fault condition without considering influence of the line distribution capacitance; according to an R-L model algorithm, a derivative of the current needs to be calculated by replacing a differential value at the midpoint moment with a differential value of two-point sampling values and replacing an instant value with a mean value; measurement is carried out in two moments to obtain twoindependent equations, and the two equations are resolved simultaneously to obtain unknown numbers R and L; and the R and L are compared with line parameters to obtain a fault distance, and a fault ranging function is realized. According to the method of the invention, the DC power distribution network is ranged accurately by double-end information measurement. The protection quickness and selectivity of the DC power distribution network can be met.

Description

technical field [0001] The invention belongs to the technical field of electric power systems, and in particular relates to a fault location method of a direct current distribution network based on an RL model algorithm. Background technique [0002] With the development of voltage source converter (voltage source converter, VSC) technology, DC load and distributed generation, DC distribution network has attracted widespread attention at home and abroad. It has the advantages of flexible control, easy acceptance of distributed power sources such as photovoltaics and DC loads, large power supply capacity, and good power quality. At present, the research on DC distribution network at home and abroad mainly focuses on topology, voltage level, protection and control, and the research on its fault location is still in its infancy. Accurate fault location can avoid manual inspection of fault points, which is of great significance to quickly repairing lines and improving power sup...

AI Technical Summary

Problems solved by technology

A large number of power electronic devices in the DC distribution network are vulnerable to fault current damage, and DC distribution network faults should be isolated within tens of milliseconds, so the online fault location method can only use the fault information of tens of milliseconds

Second, there are differences in the fault characteristics of the DC distribution network compared with the AC system. The fault transient state is obvious, and the fault current is mainly DC. The distance measurement method based on the fundamental frequency fault quantity in the AC system is difficult to directly apply to the DC distribution network.

At present, there is no widely accepted line protection scheme for DC distribution network, and further research is needed

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