Relay protection method for single-end amount of direct-current power distribution network
A DC distribution network and relay protection technology, applied in emergency protection circuit devices, electrical components, electrical digital data processing, etc., can solve the problems of single main protection principle, low sensitivity, slow action speed, etc.
Active Publication Date: 2019-12-20
XI AN JIAOTONG UNIV +2
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Problems solved by technology
This protection scheme has the problems of single main protection principle, low sensitivity, poor backup protection reliability, and slow action speed, and there is no protection principle that can reflect the existence of the fault for a long period of time after the fault
At the same time, because the medium-voltage DC distribution network is different from the traditional high-voltage DC grid in terms of topology and control characteristics
Therefore, the existing high-voltage DC line protection principles are not suitable for direct application to the medium-voltage DC distribution network, and it is of great significance to study new protection principles and schemes.
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[0030] Specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although specific embodiments of the invention are shown in the drawings, it should be understood that the invention may be embodied in various forms and is not limited to the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.
[0031] It should be noted that certain terms are used in the specification and claims to refer to specific components. Those skilled in the art should understand that they may use different terms to refer to the same component. The specification and claims do not use differences in nouns as a way of distinguishing components, but use differences in functions of components as a criterion for distinguishing. "Includes" or "comprises" mentioned throughout the spe...
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The invention discloses a relay protection method for a single-end amount of a direct-current power distribution network. The method comprises the following steps of collecting voltages and currents of positive electrodes and negative electrodes of a rectifier side M and an inverter side N of the direct-current power distribution network, calculating mode currents based on the voltages and the currents, calculating a starting current based on the 1-mode current, and calculating a high-frequency current and a low-frequency current through a band-pass filter based on the starting current; basedon the high-frequency current and the low-frequency current, calculating the amplitudes of the high-frequency current and the low-frequency current; and calculating an amplitude ratio of the high-frequency current to the low-frequency current, when the amplitude ratio is greater than a setting value of relay protection, judging that a fault exists in the direct-current power distribution network,and when the amplitude ratio is smaller than the setting value of the relay protection, judging that the fault exists outside the direct-current power distribution network.
Description
technical field [0001] The invention belongs to the technical field of direct current distribution networks, in particular to a single-ended relay protection method for direct current distribution networks. Background technique [0002] Relay protection is the first line of defense for the safe operation of the power grid. The goal of traditional AC power relay protection is to identify faults under the constraints of quick action, selectivity, sensitivity, and reliability, and finally issue fault isolation instructions to circuit breakers. The action of relay protection and mechanical circuit breaker is a typical sequential process control, and the identification and isolation of faults can be completed within 20-30ms at the fastest. [0003] However, the system architecture, working mode, and fault characteristics of the flexible DC distribution network are different from the AC distribution network, and the protection technology of the AC system cannot be copied to the D...
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IPC IPC(8): H02H7/26G06F17/50
CPCH02H7/268
Inventor 宋国兵张晨浩刘健彭书涛豆敏娜万青陈洁羽
Owner XI AN JIAOTONG UNIV