Parallel type fault energy recycling device and direct-current line bipolar short-circuit fault detection method

Abstract

The invention discloses a parallel type fault energy recycling device and a direct-current line bipolar short-circuit fault detection method, and relates to the technical field of direct-current powertransmission, particularly to a parallel type fault energy recycling device and a direct-current line bipolar short-circuit fault detection method. The parallel type fault energy recycling device isconnected in parallel between a positive electrode line and a negative electrode line of a semi-full hybrid MMC converter station, wherein the positive electrode line is sequentially connected with anisolation switch QS1 and a current-limiting reactor Lx1, the negative electrode line is sequentially connected with an isolation switch QS2 and a current-limiting reactor Lx2, a switch tube T7 is further connected in parallel between a connection point D and a connection point F, and a switch tube T5 is connected in parallel between a connecting point E and a connecting point C. According to theinvention, the parallel type fault energy recycling device can be used as stored energy to supply power to a direct-current load during normal operation, and can charge an absorption capacitor duringa fault so as to carry out secondary detection on the fault, so that fault property judgment and positioning functions are realized.

Description

technical field [0001] The invention relates to the technical field of direct current transmission, in particular to a parallel fault energy reuse device and a double-pole short-circuit fault detection method of a direct current line. Background technique [0002] In the modern power system dominated by the AC distribution network, with the development of peripheral technology research, the advantages of the DC distribution network are gradually highlighted: low line cost, low loss, large power transmission capacity, and can also reduce distributed power such as photovoltaics and wind power. The intermediate link where the power supply and DC loads are connected to the power grid, further reduces the connection cost, improves the power conversion efficiency and improves the power quality. However, engineering practice shows that the unique characteristics of "low damping" and "low inertia" of the DC distribution network lead to the rapid development of faults in the DC syste...

AI Technical Summary

Problems solved by technology

The traveling wave method requires a higher sampling frequency when used in a DC power grid, and has high requirements on the hardware of the equipment; the active injection method requires additional injection equipment, which is economical

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