A two-wire closed-loop connection method for medium-voltage distribution network

Abstract

The invention discloses a two-line closed-loop connection mode of a medium-voltage distribution network, which includes a first substation and a second substation, and is characterized in that the first substation includes a first main transformer, a second main transformer and a parallel running substation. The third main transformer and the fourth main transformer in operation, the second substation includes the fifth main transformer and the sixth main transformer in parallel operation, the seventh main transformer and the eighth main transformer in parallel operation, and the two parallel operation The lines from the bus bars of the main transformer are connected to each other to form a loop-closing unit. The invention enables the transfer capability between the loop-closing units in the medium-voltage distribution network to be flexibly configured according to the power supply reliability requirements, and the power flow distribution is simple and easy to control. The medium-voltage distribution network adopts longitudinal differential protection, so that the medium-voltage The appearance of "N-1" in the distribution network enables the fault point to be quickly isolated to restore power supply in the event of a fault, and the intelligent switching operation is realized through the equipped automation system, so that when "N-1-1", "N-2" and other faults The power supply is restored through the switching operation, the structure is simple, and the operation is convenient to implement.

Description

【Technical field】 [0001] The invention relates to a second-line closed-loop connection mode of a medium-voltage distribution network. 【Background technique】 [0002] In order to meet the user's increasingly high demand for power reliability, the medium-voltage distribution network has developed a large number of wiring methods, which can be roughly divided into open-loop operation mode and closed-loop operation mode according to different operation modes. The Singapore petal connection method and the ring connection method adopted by Hong Kong CLP Power Co., Ltd. are more mature in the application of the mode, but there are still some defects or deficiencies in the above ring connection method: [0003] The petal connection method in Singapore has the problem of limited transfer capacity between ring-closing units due to unbalanced power flow distribution; [0004] The loop-closing connection method adopted by Hong Kong CLP Power Co., Ltd. also has the problem of limited tr...

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Problems solved by technology

[0003] The petal connection method in Singapore has the problem of limited transfer capacity between ring-closing units due to unbalanced power flow distribution;

[0004] The loop-closing connection method adopted by Hong Kong CLP Power Co., Ltd. also has the problem of limited transfer capacity between loop-closing units, and also suffers from the problem of unbalanced power flow when the loop-closing unit "N-1" fails and operates normally. , resulting in a large difference between the actual load rate of the ring closing unit and the theoretical maximum load rate

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