Double-end direct-current power distribution network distributed region protection method based on current differential state quantity

Abstract

The invention discloses a double-end direct-current power distribution network distributed region protection method based on a current differential state quantity. Firstly, a medium-voltage direct-current bus is used as a boundary to carry out region division on a medium-voltage direct-current line; direct-current voltage and current amplitudes are used as fault characteristic quantities of protection starting, state word definition is carried out on a fault current differential quantity, fault type judgment and region fault positioning are carried out by utilizing the distribution condition of fault current state words, and direct-current circuit breakers at the two ends of a fault region are rapidly disconnected. Only information communication of adjacent sensors is needed, communicationdata are few, the transmission distance is short, faults can be rapidly removed when single-pole short circuit and double-pole short circuit happen to a direct-current line, the applicability is high, and the method can be used for a double-end or multi-end direct-current power distribution network in various operation modes.

Description

technical field [0001] The invention belongs to the field of relay protection for DC distribution networks, and relates to a distributed area protection method for double-terminal DC distribution networks based on current differential state quantities. Background technique [0002] In recent years, with the development of power electronics technology, DC distribution network has become an important development direction of future urban intelligent power distribution due to its advantages such as small output harmonics, large power supply capacity, high reliability, and easy access to distributed power sources. Different from the AC distribution network, when the DC distribution network fails, the fault characteristic quantity presents the characteristics of aperiodicity, nonlinearity, and fast change speed. In terms of protection quickness, the DC distribution network is higher than the AC distribution network. After a short-circuit fault between poles, the DC side capacitor...

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Problems solved by technology

[0003] Purpose of the invention: The purpose of the invention is to solve the problem that the fault current rises rapidly after a short circuit between poles occurs in the DC distribution network, and the amplitude is high, causing irreversible impacts on IGBTs and diodes, and the problems of large-scale power outages caused by traditional protection schemes

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