Data acquisition and processing system for small current neutral grounding line selection

Abstract

The invention discloses a data acquisition and processing system for small current neutral grounding line selection. The data acquisition and processing system comprises a zero-sequence current signal processing module, a data interface CAN module, a single chip microcomputer signal processing module and a power source transformation processing module. Quintuple harmonic signals are amplified while zero-sequence current signal fundamental waves are processed, the signal to noise ratio of the quintuple harmonics is improved, comprehensive data analysis is facilitated, mistaken selection and wrong selection are deceased, and line selection accuracy rate is improved. The data acquisition and processing system can simultaneously detect three output lines and provide a hardware environment for 'amplitude and phase comparing algorithm', 'quintuple harmonic algorithm' and other comprehensive line selection principles of a line mainframe, meanwhile improves the line selection effectiveness, facilitates line expansion, can be effectively resistant to electromagnetic interference through RS485 bus communication and is large in communication distance and simple in networking, the complexity of the system is reduced, cost is reduced, and the maintenance amount of the system is reduced. The data acquisition and processing system achieves synchronous data acquisition and transmission and is good in real-timeliness, quick in response, capable of achieving data pre-processing and high in anti-interference capacity.

Description

technical field [0001] The invention belongs to the field of relay protection of power systems, and in particular relates to a data acquisition and processing system for small current grounding line selection. Background technique [0002] my country's 6-35KV distribution network widely adopts the central point non-effective grounding method, also known as the small current grounding system. More than 70% of the faults in the small current grounding system are single-phase grounding faults. [0003] The traditional line selection device has only one line selection host, which only analyzes and compares the fundamental wave or the 5th harmonic of the zero-sequence current signal, but the signal-to-noise ratio of the 5th harmonic in the fundamental wave is very small, accounting for only the fundamental wave About 3% of the zero-sequence signal is easily affected by noise, and the zero-sequence signal cannot be effectively compared with comprehensive data, which is prone to m...

AI Technical Summary

Problems solved by technology

[0004] The invention proposes a data acquisition and processing system for small current grounding line selection, which solves the problem of low line selection accuracy in the

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