Harmonic Ratio Reclosing Control for Arc Extinction Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional reclosing methods in transmission lines often result in unnecessary dead time and potential power system instability due to incomplete fault removal and reclosing operations, especially in cases of transient faults like lightning-induced issues.
Innovation Solution
A reclosing control device and method that utilizes a harmonic ratio (HR) to detect the final extinction point of an arc by calculating the ratio between even and odd harmonics in the faulted phase voltage waveform, allowing for precise determination of arc extinction and optimized reclosing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional auto reclosing method with predetermined dead time is used, then reclosing operation can be performed after fault occurrence, but unnecessary dead time remains and reclosing may be performed even when arc is not completely extinguished or permanent fault exists
Solution Approach 1:
The patent changes the parameter used for reclosing decision from fixed time-based control to harmonic ratio-based control. By monitoring the harmonic ratio (ratio of even harmonics to odd harmonics) of the voltage waveform, the system can dynamically determine when the arc is completely extinguished, eliminating the need for predetermined dead time and enabling more reliable reclosing decisions.
Solution Approach 2:
The patent replaces the mechanical time-delay mechanism with a harmonic analysis-based detection system. Instead of using a fixed time delay after fault occurrence, the system uses harmonic ratio calculation and comparison to detect arc extinction, substituting the time-based mechanical control with a more sophisticated electrical parameter-based control system.
2Productivity
If conventional auto reclosing method is used, then reclosing can be performed after fault, but power system stability may be threatened and power equipment loss may occur due to reclosing on permanent faults
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring the harmonic ratio of the voltage waveform and using this information to control the reclosing operation. The system compares the calculated harmonic ratio with a predetermined threshold and only performs reclosing when the harmonic ratio indicates complete arc extinction, providing feedback-based control that prevents reclosing on permanent faults while maintaining power supply continuity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach minimizes unnecessary dead time, enhances power supply reliability, and stabilizes reclosing operations by accurately detecting the arc extinction point, reducing the risk of power system instability and equipment loss.
Implementation Method 1
a voltage detection unit for detecting a faulted phase voltage waveform and for extracting a harmonic component contained in the faulted phase voltage waveform
Data Source
AI summary
The reclosing control device configured to perform a reclosing control in case of a fault in a transmission line. Further, the reclosing control device includes a voltage detection unit configured to detect a faulted phase voltage waveform and extract a harmonic component contained in the faulted phase voltage waveform; a HR calculating unit configured to calculate ratio values between even harmonics and odd harmonics based on the extracted harmonic component; and a reclosing control unit configured to determine whether or not an arc is finally extinguished based on the calculated ratio value and perform a reclosing control depending on a result of the determination.