Detecting device for exciting current at magnetic bias moment of transformer based on wavelet transformation and working method

A technology of excitation current and wavelet transform, applied in the direction of using digital measurement technology for measurement, etc., can solve problems such as generating harmonics, threatening the safe operation of power systems, and transformer DC bias.

CN102841243AInactive Publication Date: 2012-12-26TIANJIN UNIVERSITY OF TECHNOLOGY
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2012-12-26
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to a detecting device for an exciting current at a magnetic bias moment of a transformer based on wavelet transformation. The detecting device comprises a power transformer with a grounded neutral point and a host computer, and is characterized by further comprising a current sensor, an analog-digital conversion module, a DSP (Digital Signal Processor) control unit, an FLASH memory, a synchronous dynamic random access memory, a CPLD (Complex Programmable Logic Device) control unit and a USB (Universal Serial Bus) interface. The working method of the detecting device comprises the following steps of: collecting a signal; processing the signal; judging; analyzing; and solving an average value. The detecting device has the advantages of simple hardware, easy understanding of software, strict timing sequence, high stability, strong operability, and instantaneity of data transmission.
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Description

(1) Technical field:

[0001] The invention belongs to the field of power system signal detection, in particular to a wavelet transform-based excitation current detection device and working method for transformer bias. (2) Background technology:

[0002] With the construction and operation of large-capacity and long-distance DC transmission systems, the ground pole current of the DC transmission system operating with the earth as the return mode will flow into the transformer excitation winding through the neutral point of the transformer. , which will cause the DC bias phenomenon of the transformer, which will lead to the distortion of the excitation current of the transformer, the generation of harmonics, and the change of reactive power, which will affect the correct action of relay protection and threaten the safe operation of the power system. Therefore, how to ensure the accurate operation of the relay protection device when the DC bias phenomenon occurs in the power tra...

Examples

Embodiment

[0042] Embodiment: A kind of excitation current detection device when the transformer is biased based on wavelet transform (see figure 1 ), including a power transformer with a neutral point grounding, and a host computer, which is characterized in that it includes a current sensor, an analog-to-digital conversion module, a DSP control unit, a FLASH memory, a synchronous dynamic random access memory, and a CPLD (Complex Programmable Logic Device—complex programmable logic device) control unit and USB interface; wherein, the current sensor detects the excitation current signal in the transformer excitation winding, and its output terminal is connected to the input terminal of the analog-to-digital conversion module; the input terminal of the DSP control unit receives the modulus The digital signal that conversion module sends, its output end is connected with the input end of CPLD control unit, and DSP control unit is also bidirectionally connected with FLASH memory and synchro...