A DC line protection method and device for a DC distribution network
A technology of DC distribution network and DC line, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problem of easy misoperation of protection
Active Publication Date: 2022-02-18
XJ ELECTRIC +2
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Problems solved by technology
[0004] The purpose of the present invention is to provide a DC line protection method and device for a DC distribution network, which is used to solve the problem that the existing DC line protection only considers the information on the local side, resulting in easy misoperation of the protection
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[0028] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0029] The embodiment of the protection method for the DC line of the DC distribution network:
[0030] like figure 1 As shown in the DC line of the DC distribution network, the AC system is converted into DC through inverter 1 and inverter 2, respectively, and then connected to the positive bus and the negative bus. make contact. Break1 and Break2 are circuit breakers at both ends of the positive line, Break3 and Break4 are circuit breakers at both ends of the negative line, respectively; CT1 and CT2 are the analog measurement points at both ends of the positive line, CT3 and CT4 are the analog measurement points at both ends of the negative line, respectively. Both ends of the positive line are respectively equipped with DC line pro...
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The present invention relates to a DC line protection method and device of a DC distribution network, including: judging whether the line protection startup judgment is satisfied according to the current and voltage of the line side; if the line protection startup judgment is satisfied, judging whether the following conditions are met: 1. ) did not receive the fault start reverse signal on the opposite side of the line; 2) the current on this side of the line is the set positive direction; among them, for the positive line, the direction of the current on both sides is the set positive direction based on the bus bar flowing into the line; for the negative line The direction of the current on both sides of the line is the positive direction set by the line flowing into the bus; 3) The current on the side of the line meets the set operating conditions; if it is satisfied, the DC line protection will operate after a set time delay. The invention eliminates a fault on the opposite side of the line by receiving a fault start signal from the opposite side of the line, and can reliably determine whether a fault occurs on the own side of the line, thereby effectively avoiding the problem of malfunction of protection on the own side of the line caused by a fault on the opposite side of the line.
Description
technical field [0001] The invention relates to a DC line protection method and device for a DC distribution network, and belongs to the technical field of relay protection of a power system distribution network. Background technique [0002] In recent years, with the rapid growth of DC loads such as electric vehicle charging stations and data centers, and the access of large-capacity distributed power sources such as a high proportion of photovoltaics and energy storage, the traditional AC power distribution system is facing huge challenges. Compared with the AC distribution network, the DC distribution network has the advantages of large transmission capacity, high power quality, good system stability, and easy access to distributed energy. It is widely used in load centers, integrated energy systems, ship / aviation systems and other scenarios, and the DC distribution network will become the development direction of the future distribution network. The DC distribution netw...
Claims
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IPC IPC(8): H02H7/26
CPCH02H7/268
Inventor 刘洋李俊刚常彦彦孟乐吴水兰姜睿智孙文龙
Owner XJ ELECTRIC