Ground Impedance Estimation Using Intermediary Leakage Current
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Solution Overview
Problem
Existing devices for estimating the impedance of an electrical ground connection cannot accurately measure impedance when connected to multiple electrical installations on the same network, as they generate significant leakage currents, preventing precise measurement.
Innovation Solution
A device comprising an electrical component with a predetermined impedance connected in series between the phase and ground conductors, along with sensors and a calculation unit to measure voltage differences in open and closed states, allowing for the estimation of the total ground impedance without causing additional leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a voltage generator and current sensor are connected in series between phase and ground conductors to measure impedance, then the impedance measurement can be performed, but significant leakage currents are generated that prevent precise measurement when multiple electrical installations are connected to the same network
Solution Approach 1:
The patent introduces an intermediary measurement approach using existing leakage current from the electrical installation itself rather than injecting additional test current. The device measures the voltage across the ground connection while utilizing the naturally occurring leakage current as the test signal, thereby avoiding the generation of harmful additional leakage currents while still enabling impedance measurement.
Solution Approach 2:
The measurement system uses the electrical installation's own leakage current characteristics to perform the ground impedance measurement. Instead of an external voltage generator injecting current, the system leverages the self-generated leakage current of the connected installation, making the measured installation serve its own measurement needs and eliminating the harmful effect of additional leakage current generation.
2Adaptability or versatility
If a voltage generator is used to impose voltage for impedance measurement, then impedance can be calculated from voltage and current values, but the device cannot be installed on multiple electrical installations of the same network due to significant additional leakage currents
Solution Approach 1:
The patent employs an intermediary measurement strategy that uses the existing electrical network's leakage current as the measurement signal. By measuring voltage across the ground connection while using the naturally occurring leakage current (rather than injecting additional current), the device achieves universal compatibility across multiple installations without generating harmful additional leakage currents that would interfere with network operation.
Solution Approach 2:
Each electrical installation's own leakage current serves as the measurement signal for ground impedance assessment. The system is designed to work with the self-generated leakage current of any connected installation, enabling universal deployment across multiple installations on the same network without requiring external voltage generators that would create harmful additional leakage currents.
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
Enables precise estimation of ground impedance across multiple electrical installations on the same network, preventing electrocution risks by disconnecting power when impedance exceeds a threshold and allowing for correct grounding checks in various electrical systems.
Implementation Method 1
an electrical component with a predetermined impedance connected in series between the phase and ground conductors
Data Source
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AI summary
This device (36) for estimating the impedance of an earth connection (22), the earth connection being connected to the earth of an alternating electrical network (14) comprising a phase connected to a phase conductor (18) and a neutral connected to a neutral conductor (20), comprises: - an electrical component (38) of predetermined impedance disposed between the phase conductor and the earth connection; - a first sensor (42) suitable for measuring a first value of a first quantity between the phase conductor and the earth connection and a second value of the first quantity; - a second sensor (44) suitable for measuring a first value of a second quantity between the neutral conductor and the earth connection and a second value of the second quantity; - a calculating element (46) for the impedance of the earth connection.