Common-Mode Voltage Bridge Measurement for Fault Localization
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Solution Overview
Problem
Existing methods for detecting faults in electrical energy distribution networks, particularly series arcs, are unreliable and prone to false positives, especially in direct networks, as they rely on temporal or spectral analysis of current and voltage signals, which are difficult to implement and inefficient in detecting series arcs.
Innovation Solution
A device and method that measure common mode voltage and network current using resistive and capacitive sensors to calculate a mixed energy integral, allowing for the detection and localization of faults, including series arcs, by distinguishing between network, residual, and mixed energies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temporal or spectral analysis of current and voltage signals is used to detect faults, then fault detection capability is provided, but the method is difficult to implement and produces many false positives
Solution Approach 1:
The patent extracts and measures only the common mode voltage component separately from the differential mode signals. By using a bridge circuit with resistive elements connected between power conductors and a common mode sensor connected to the common conductor, the invention isolates the common mode voltage for measurement, eliminating the need for complex temporal or spectral analysis of combined signals.
Solution Approach 2:
The patent introduces a bridge circuit with resistive elements as an intermediary between the power conductors and the measurement system. This bridge circuit transforms the measurement of common mode voltage into a simpler measurement task by providing a proportional voltage signal that can be directly measured without complex signal processing.
2Reliability
If usual protection devices trigger on excessive current or power consumption, then protection function is provided, but series arcs developing over long periods without overcurrent are not detected early
Solution Approach 1:
The patent extracts the common mode voltage component which contains information about series arcs, separating it from the differential mode current and voltage signals. This extraction allows direct measurement of common mode voltage variations that indicate series arc conditions, enabling early detection before overcurrent conditions develop.
Solution Approach 2:
The patent replaces the traditional current-based detection mechanism with a voltage-based detection mechanism. By measuring common mode voltage instead of analyzing current magnitude or spectral content, the system can detect series arcs earlier and more reliably without waiting for overcurrent conditions.
3Adaptability or versatility
If temporal or spectral analysis methods are used, then fault detection is attempted, but the methods are particularly difficult to implement in direct networks
Solution Approach 1:
The patent extracts and measures only the common mode voltage component in direct networks, eliminating the need for complex spectral analysis. The bridge circuit with resistive elements connected to the common conductor provides a direct voltage measurement that is specifically adapted to direct network configurations, simplifying implementation while maintaining versatility.
4Measurement precision
If common mode voltage is measured using a bridge with resistive elements, then measurement of common mode voltage is achieved, but the sensor must be precisely balanced to avoid detection errors
Solution Approach 1:
The bridge circuit with resistive elements is designed to be self-balancing through the inherent symmetry of the circuit configuration. The resistive elements naturally equalize the potential distribution, and the common mode measurement automatically compensates for minor imbalances, reducing the need for external calibration or precise manual balancing.
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 solution provides a reliable and efficient means to detect and localize a wide variety of faults, including series arcs, reducing false positives and improving fault detection in severe environments by analyzing energy imbalances within the network.
Implementation Method 1
a sensor formed by two resistive elements intended to be arranged in a bridge between the two power conductors and having identical resistance values to each other
Implementation Method 2
a measuring dipole connected on the one hand to the midpoint and on the other hand to a connection terminal which is intended to be electrically connected to the common conductor
Data Source
AI summary
The invention relates to a member (O1) for measuring a magnitude representative of a common mode voltage (Vres) in an electrical network (1) or in an equipment (E), the network (1) or the equipment (E) comprising at least one first power conductor (C1) and a second power conductor (C2). The measuring member (O1) comprises a sensor formed by two resistive elements (R1, R2) which are intended to be arranged in a bridge between the two power conductors (C1, C2) and have resistance values which are identical to each other. The two resistive elements (R1, R2) are connected at a midpoint (T3). The sensor also comprises a measuring dipole (SH) connected to the midpoint (T3) and to a connection terminal intended to be electrically connected to a common conductor (Cc), of which the electrical network (1) or the equipment (E) has been equipped.