Ground Fault Detection via Double Integration
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Solution Overview
Problem
Existing methods for detecting ground faults in electrical power distribution networks and transmission lines are unreliable due to periodic sign changes and zero resets in zero-sequence system power and energy values, leading to unfavorable evaluation points.
Innovation Solution
A method that integrates energy values to form a comparison signal with the physical dimension of Planck's constant, which rises monotonically and remains above zero, allowing for more reliable error evaluation independent of time, using zero-sequence system power values without averaging, and generating a ground fault signal based on threshold comparisons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If zero-sequence system power values and energy values are used for ground fault detection, then ground fault detection is enabled, but periodic sign changes and zero resets create unfavorable evaluation points that reduce reliability
Solution Approach 1:
The patent transforms the evaluation parameter from zero-sequence energy values (which periodically reset to zero) to a comparison signal based on double integration of power values. This parameter transformation eliminates the periodic zero resets and sign changes, creating a monotonically increasing signal that provides stable evaluation points throughout the measurement period, thereby resolving the contradiction between enabling detection and maintaining measurement precision.
2Reliability
If energy values are integrated to form comparison signal, then evaluation becomes independent of time and zero-point contacts are eliminated, but the device complexity increases due to double integration requirement
Solution Approach 1:
The patent moves from single integration (energy values) to double integration (comparison signal), effectively adding a temporal dimension to the accumulation process. This dimensional extension transforms the periodically fluctuating energy values into a monotonically increasing comparison signal that accumulates deviations over time, eliminating zero-point evaluation issues while the increased mathematical operation complexity is managed through efficient computational implementation.
3Stability of the object's composition
If power values are time-averaged before integration, then calculation stability is improved, but response speed to ground faults is reduced
Solution Approach 1:
The patent extracts and eliminates the time-averaging step from the conventional method, working directly with instantaneous power values. By removing the averaging operation that smooths out rapid changes, the system achieves faster response to ground faults. The stability previously provided by averaging is instead achieved through the double integration process, which naturally filters high-frequency fluctuations while preserving the monotonically increasing comparison signal characteristic.
Data Source
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AI summary
The invention relates, among other things, to a method for detecting a ground fault in an electrical power distribution network or on an electrical power transmission line. In this method, energy values are generated by integrating power values, and these energy values are used to determine whether a ground fault exists and whether a ground fault fault signal (F) should be generated. According to the invention, a further integration is performed in which the energy values are integrated to form a reference signal (iw0(t)), and this reference signal (iw0(t)) is used to determine whether a ground fault exists and whether the ground fault fault signal (F) should be generated.