Distance Protection Polygon Closure via Tilt Angle Adjustment
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Solution Overview
Problem
The setting value for the tilt angle in distance protection systems may be inappropriate, leading to an open operate region due to the boundary lines of the polygonal operation characteristic not forming a closed loop, which can result in ineffective fault detection.
Innovation Solution
Adjust the tilt angle from the received setting value to the nearest value that results in a closed operation characteristic, optionally with a predetermined margin, to ensure a closed operate region while minimizing deviation from the original setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tilt angle setting value is used directly to form the polygonal operation characteristic, then the setting value is maintained as specified, but the operation characteristic may not form a closed loop resulting in an open operate region
Solution Approach 1:
The patent applies preliminary action by checking whether the received tilt angle setting value will result in a closed operation characteristic before finalizing the setting. The system pre-calculates or pre-verifies the geometric closure of the polygonal operation characteristic based on the received tilt angle, and only accepts the setting if it guarantees a closed loop. This prevents the formation of open operate regions while maintaining the original setting intent.
Solution Approach 2:
The patent implements feedback by monitoring the geometric outcome of the tilt angle setting and providing information back to the setting process. When the received tilt angle would result in an open operate region, the system detects this condition and communicates it back, triggering a response such as rejecting the setting, alerting the operator, or automatically adjusting the tilt angle to a value that ensures closure. This feedback loop ensures reliability while managing the precision trade-off.
2Reliability
If the tilt angle is adjusted to ensure a closed operation characteristic, then the operate region is guaranteed to be closed, but the deviation from the original setting value increases
Solution Approach 1:
The system performs preliminary verification of the tilt angle setting to determine if adjustment will be needed. By pre-calculating the operation characteristic geometry based on the received tilt angle, the system can identify settings that would result in open regions before they are applied, allowing for proactive correction while minimizing the need for post-adjustment deviations.
Solution Approach 2:
The patent applies partial action by adjusting the tilt angle only to the extent necessary to achieve closure of the operation characteristic. Rather than making large or excessive adjustments, the system modifies the tilt angle by the minimum amount required to close the polygonal loop, thereby maintaining fidelity to the original setting intent while ensuring operational reliability. This selective adjustment minimizes deviation from the received setting value.
Data Source
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AI summary
A method and an apparatus for distance protection of a three-phase electric line (30), the apparatus (40) being configured to receive one or more setting values of characteristic quantities for forming a polygonal operation characteristic, determine if an operation characteristic formed according to the received one or more setting values defines a closed area, and in response to determining that the operation characteristic formed according to the received one or more setting values does not define a closed area, adjust a value of a tilt angle of at least one of lines defining the operation characteristic from a received setting value to a nearest value that results in the operation characteristic defining a closed area, and form the operation characteristic by applying the thus obtained adjusted value of the tilt angle.