Linkage protection device for transformer neutral point DC blocking equipment and method thereof

Abstract

The invention provides a linkage protection device for transformer neutral point DC blocking equipment and a method thereof. The linkage protection device comprises the components of an access bus which is connected with N sets of DC blocking equipment, wherein N is a positive integer which is larger than or equal with 2; a main controller which is used for monitoring state information of each set of DC blocking equipment and transmitting an instruction for triggering already acted DC blocking equipment to make a corresponding transformer neutral point be grounded when a condition that the states of the DC blocking equipment are not totally same is determined according to the state information of each set of DC blocking equipment; and a data conversion module which is connected with the access bus and the main controller and is used for converting data in the access bus to the data that are readable by the main controller and converting the instruction that is transmitted by the main controller for transmitting to the access bus. When a fault or power failure of certain DC blocking equipment occurs and the DC blocking equipment cannot operate, other sets of DC blocking equipment in normal operation can be shunted, and all transformers directly perform grounded operation, thereby sharing a DC current and preventing bearing of an overlarge DC current by a certain transformer. Furthermore the plurality of sets of equipment share one linkage protection device, thereby realizing cost saving.

Description

technical field [0001] The invention relates to the field of transformer protection, in particular to a linkage protection device and method for transformer neutral point DC blocking equipment. Background technique [0002] High voltage direct current transmission (HVDC) system has been more and more widely used due to its characteristics of long transmission distance, large transmission capacity, and flexible control. The mutual influence is also more obvious. When the DC transmission system is operated with unipolar grounding or bipolar unbalanced operation, the DC current will be injected into the ground through the grounding pole, and the DC current in the ground will invade the AC system through the neutral point grounding wire of the transformer, which will have an impact on the AC system. The most significant impact is Causes the DC bias of the transformer to appear. [0003] In order to suppress the impact of DC transmission on the operation of transformers, more a...

AI Technical Summary

Problems solved by technology

[0004] However, many power plants or substations have multiple neutral-point grounding transformers. If the neutral-point blocking equipment of a certain transformer fails or the equipment fails to operate when the DC current increases, the transformer alone bears the responsibility. All DC current, no other transformers to share, the DC current may exceed the design limit of the transformer, and even cause damage to the transformer

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