Single-Phase Meter Cut-Off for Neutral Break Overvoltage
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Solution Overview
Problem
In three-phase electrical systems, a break in the neutral line can cause voltage imbalances, leading to significant increases in voltage at some electrical installations, potentially damaging equipment, especially when single-phase electric meters without cut-off devices are used.
Innovation Solution
A single-phase electric meter with a cut-off member, upstream voltage sensor, and processing means to measure and manage voltage thresholds, opening the cut-off member when upstream voltage drops below a predetermined level to protect connected electrical installations from excessive voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-phase electric meter without a cut-off device is used, then the device complexity is reduced and cost is lowered, but the electrical installation becomes vulnerable to voltage increases that can damage equipment
Solution Approach 1:
The patent introduces an intermediary protection system consisting of a monitoring device and a cut-off device that acts as a mediator between the electrical meter and the electrical installation. The monitoring device detects voltage anomalies caused by neutral breaks, and the cut-off device interrupts the circuit to protect downstream equipment, thereby providing protection without requiring modification to the meter itself.
Solution Approach 2:
The protection function is segmented into separate components: a monitoring device for detecting voltage conditions, a cut-off device for interrupting the circuit, and control logic for coordinating their operation. This segmentation allows the protection function to be added independently of the meter, reducing overall system complexity while maintaining reliability.
2Reliability
If a cut-off device with voltage measurement is added to the electric meter, then equipment protection is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
Instead of integrating the cut-off and monitoring functions directly into the meter, the patent uses an intermediary monitoring device that communicates with a separate cut-off device. This intermediary approach provides the necessary protection functionality while keeping the meter structure simple and avoiding complex integration challenges.
Solution Approach 2:
The monitoring device autonomously detects voltage conditions and triggers the cut-off device without requiring complex meter intervention. The system serves itself by using simple voltage sensing and predefined thresholds to activate protection, minimizing the need for complex meter-based control logic.
3Speed
If the monitoring device continuously monitors voltage, then the response time to voltage anomalies is improved, but the energy consumption increases
Solution Approach 1:
The monitoring device performs voltage measurements at periodic intervals rather than continuously, reducing energy consumption while maintaining effective monitoring. The periodic measurement cycle is configured to detect neutral break conditions within acceptable timeframes, balancing response speed with energy efficiency.
Solution Approach 2:
The monitoring device uses threshold-based detection that allows it to skip detailed analysis during normal conditions and rapidly respond when voltage anomalies exceed predefined thresholds. This approach enables fast response to critical events while minimizing energy expenditure during stable operating conditions.
Data Source
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AI summary
A single-phase electric meter (10) comprising a phase conductor (21) intended to be connected to a phase (5) of an electric line located upstream of the single-phase electric meter and to a phase (16) of an electric installation (1) located downstream of the single-phase electric meter, the single-phase electric meter (10) further comprising a breaking unit (20) mounted on the phase conductor (21), an upstream voltage sensor (25) arranged to periodically measure an upstream voltage (Va) upstream of the breaking unit (20), and processing means (29) arranged to acquire upstream voltage measurements and to open the breaking unit (20) when the upstream voltage (Va) drops below a first predetermined threshold voltage.