Fault Current Calculation Using Unsaturated Waveform Regions
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Solution Overview
Problem
Existing methods for calculating fault current in electric power delivery systems are inefficient during current transformer saturation, leading to inaccurate fault location and increased power consumption in line-mounted devices.
Innovation Solution
A computationally efficient method is developed to calculate fault current using the unsaturated region of the current waveform, which involves determining peak values and removing fictitious peaks to accurately determine the unsaturated regions, allowing for precise fault magnitude calculation even under saturated current transformer conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional fault current calculation methods are used during current transformer saturation, then computational accuracy is maintained, but power consumption increases and processing efficiency decreases
Solution Approach 1:
The current waveform is segmented into saturated and unsaturated regions. The method identifies and separates the unsaturated portion of the waveform, which contains valid measurement data, from the saturated portion. This segmentation allows the system to process only the useful unsaturated region, reducing computational load and power consumption while maintaining accurate fault current calculation.
Solution Approach 2:
The method extracts the unsaturated region from the saturated current waveform by identifying peak values and removing fictitious peaks. By taking out and processing only the valid unsaturated portion of the waveform, the system achieves accurate fault current calculation without the need to process the entire saturated waveform, thereby reducing power consumption and computational requirements.
2Measurement precision
If traditional fault current calculation methods are used during current transformer saturation, then complete waveform processing is performed, but computational efficiency decreases and processing time increases
Solution Approach 1:
The waveform processing is segmented to identify and process only the unsaturated region. By dividing the waveform into saturated and unsaturated portions and processing only the latter, the computational complexity is significantly reduced while maintaining calculation accuracy, thereby improving productivity and processing efficiency.
Solution Approach 2:
Instead of processing the complete saturated waveform, the method applies partial action by processing only the unsaturated region of the waveform. This partial processing approach is sufficient to obtain accurate fault current calculations without the excessive computational burden of processing the entire waveform, thus improving computational efficiency.
3Reliability
If complete current waveform processing is performed during saturation, then all data is utilized, but device complexity and processing requirements increase
Solution Approach 1:
The method segments the waveform processing task to focus only on the unsaturated region, which contains the reliable data needed for accurate fault location. This segmentation simplifies the processing requirements and reduces device complexity while maintaining the reliability needed for accurate fault location determination.
Solution Approach 2:
The method extracts and processes only the unsaturated region from the waveform, removing the need to process the saturated portion that contains distorted data. This extraction approach reduces processing complexity and device requirements while maintaining the reliability of fault location accuracy by utilizing only the valid unsaturated data.
Data Source
AI summary
Line-mounted devices for determining fault magnitude in an electric power delivery system even under current-transformer (CT) saturation are disclosed herein. Fault magnitude is calculated using unsaturated regions of a current waveform captured by the line-mounted device. The method of determining the unsaturated regions is computationally efficient. Fictitious peaks are removed, and the unsaturated regions are determined based on fractions of the valid peaks. Fault current magnitude is calculated using sample values in the unsaturated regions.