Segmented Rogowski Coil Current Sensing for Adjacent Phase Rejection
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Solution Overview
Problem
Single Rogowski coil sensors struggle to accurately measure current when adjacent phase lines or conductors are in a fault condition, leading to erroneous measurements due to induced currents from nearby faults.
Innovation Solution
A multiport current sensor system utilizing multiple Rogowski coil segments positioned around a monitored conductor, with each segment generating voltage signals that are processed to distinguish between load current and adjacent phase fault current, and an adjacent phase rejection circuit to filter out interference from nearby faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single Rogowski coil sensor is used to measure current in a monitored phase line, then the device complexity is reduced, but measurement precision deteriorates due to induced currents from adjacent phase line faults
Solution Approach 1:
The Rogowski coil sensor is divided into multiple segments (first Rogowski coil segment, second Rogowski coil segment, etc.), each positioned at different locations around the monitored phase line. This segmentation allows the system to distinguish between currents induced by the monitored phase and those induced by adjacent phase faults, thereby improving measurement precision while maintaining reasonable device complexity
Solution Approach 2:
The patent transitions from a single-point measurement approach to a multi-location measurement approach by positioning Rogowski coil segments at different spatial locations around the phase line. This dimensional expansion in spatial distribution enables the system to differentiate between various current sources and improve measurement accuracy
2Measurement precision
If multiple Rogowski coil segments are positioned at different locations around the monitored phase line, then measurement precision improves by distinguishing load current from fault current, but device complexity increases
Solution Approach 1:
The Rogowski coil sensor is divided into multiple segments (first Rogowski coil segment, second Rogowski coil segment, etc.), each positioned at different locations around the monitored phase line. This segmentation allows the system to distinguish between currents induced by the monitored phase and those induced by adjacent phase faults, thereby improving measurement precision while maintaining reasonable device complexity
Solution Approach 2:
The system uses the differential output signals from multiple Rogowski coil segments to detect and reject induced currents from adjacent phase faults. By comparing signals from different locations and applying rejection logic, the system feedbacks to eliminate measurement errors, improving precision without proportionally increasing complexity
3Reliability
If Rogowski coil segments are positioned closer to adjacent phase lines to improve fault detection, then fault detection capability improves, but susceptibility to induced currents increases
Solution Approach 1:
The Rogowski coil sensor is divided into multiple segments (first Rogowski coil segment, second Rogowski coil segment, etc.), each positioned at different locations around the monitored phase line. This segmentation allows the system to distinguish between currents induced by the monitored phase and those induced by adjacent phase faults, thereby improving measurement precision while maintaining reasonable device complexity
Solution Approach 2:
The system converts the harmful induced currents from adjacent phase faults into useful diagnostic information. By detecting the presence and characteristics of these induced currents through multiple Rogowski coil segments, the system can identify fault conditions and differentiate them from actual load currents, transforming interference into a fault detection mechanism
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
The system effectively filters out interference from adjacent phase faults, ensuring accurate current measurement and preventing false fault indications, thereby improving the reliability of current sensing in closely spaced electrical conductors.
Implementation Method 1
A first Rogowski coil segment to generate a first voltage signal via a first port in response to current induced within the first Rogowski coil segment
Data Source
AI summary
A multiport current sensor is disclosed for measuring current. The sensor may include multiple CT or Rogowski coil segments or sections arranged in a closed loop configuration around a monitored phase line or other electrical conductor. An adjacent phase rejection circuit compares the magnitudes and/or phase angles of the voltage signals from the multiple coil segments. The adjacent phase rejection circuit may detect if a fault in an adjacent phase line or other electrical conductor is affecting the output signal of the current sensor by more than a threshold amount. The adjacent phase rejection circuit may additionally or alternatively indicate whether the measured values are valid for detecting a fault on the monitored phase line or other electrical conductor.