Method for improving valve short circuit protection and setting performance of current converter

Abstract

The invention relates to a method for improving the valve short circuit protection and setting the performance of a current converter. With a valve short circuit action function, the invention has a function of positioning a fault bridge and improves the overall performance of a constant value for the valve short circuit protection. In addition, aiming at the defects of braking function of the valve short circuit protection, the invention provides a sectional type braking function considering the selectivity and the sensitive requirements; and by combining the running characteristics of a high-voltage direct current power output system, the invention provides a practical parameter determination method aiming at the sectional type function. For the valve short circuit protection of the high-voltage direct current power output system, the invention can consider the requirements for meeting the sensitivity and the selectivity during fault generation.

Description

technical field [0001] The invention belongs to the technical field of relay protection for high-voltage direct current transmission systems, in particular to a method for improving the short-circuit protection setting performance of a converter valve, and belongs to the innovative technology of the method for improving the short-circuit protection setting performance of a converter valve. Background technique [0002] In order to ensure the safety of the primary DC equipment and the stable operation of the AC-DC interconnection grid, a complete DC protection system is configured in the HVDC (High Voltage Direct Current) project. Converter valve overstress is one of the most serious accidents in DC transmission systems. When the converter valve is short-circuited, the AC side of the converter is short-circuited between phases, or the DC side of the valve hall on the rectifier side is short-circuited (hereinafter referred to as the specified faults of the valve short-circuit ...

AI Technical Summary

Problems solved by technology

[0007] From the above analysis, it can be seen that the widely used valve short circuit protection action equation has the following defects: ①The second type of valve short circuit protection only uses one action equation for the entire converter, so it does not have the function of locating the fault bridge; ②The two types of valve short circuit protection only use one action equation for the entire converter; The braking functions of short-circuit protection are constant and linear braking functions respectively. When the fault short-circuit current outside the area increases, due to the increase of unbalanced current entering the protection, the first type of protection may malfunction; the second type of protection is to ensure The selectivity of faults outside the zone requires a larger value of the braking coefficient, which may refuse to move under active faults in the zone

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