Lightning Protection Switch for Earth Fault Detection

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Solution Overview

Problem

Existing protection devices for electrical appliances against lightning strikes are inadequate, as they may fail to effectively evacuate lightning currents to the ground, potentially damaging connected devices and posing a safety risk to users, especially when the earth terminal is faulty or absent.

Innovation Solution

A device with a switch controlled by an earth detection mechanism that connects the lightning arrester to the earth terminal only when it is present, preventing lightning currents from propagating to other devices and ensuring safe evacuation of currents to the ground.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the protection device is connected to the earth terminal to evacuate lightning currents, then the protection effectiveness is improved, but the risk of damaging other devices and causing safety hazards increases when the earth terminal is faulty or absent

Engineering Contradiction:
Improveprotection effectivenessVSAvoiddamage to other devices and safety hazards
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies the dynamics principle by making the connection between the evacuation component and earth terminal dynamic rather than static. A switch controlled by an earth detection mechanism automatically connects the evacuation component to earth when a proper earth connection is detected, and disconnects it when no earth connection is present. This dynamic adaptation resolves the contradiction by enabling effective lightning current evacuation only under safe conditions, preventing damage to other devices and safety hazards when the earth terminal is faulty or absent.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback through an earth detection mechanism that continuously monitors the status of the earth terminal and controls the switch accordingly. The detection mechanism provides feedback about the presence and quality of the earth connection, allowing the system to automatically adjust its behavior. When proper earth connection is detected, the switch closes to enable current evacuation; when earth connection is absent or faulty, the switch opens to prevent harmful effects, thus resolving the contradiction between protection effectiveness and safety.

Inventive Principle:
Principle #23Feedback

2Reliability

If the earth detection mechanism and switch are added to control the connection, then the safety is improved, but the device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies the self-service principle by designing a system that automatically detects the earth connection status and controls its own operation without external intervention. The earth detection mechanism and switch work autonomously to ensure safe operation, eliminating the need for manual configuration or monitoring by users. This self-service approach improves safety while keeping the device relatively simple, as the added components perform their functions automatically based on real-time conditions.

Inventive Principle:
Principle #25Self-service

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 effectively prevents lightning currents from damaging connected devices and ensures user safety by ensuring that lightning currents are only evacuated to the earth terminal when it is properly connected, thereby reducing the risk of fire and electrical hazards.

Implementation Method 1

a first switch (20) which is mounted between the evacuation component (18) and the connection element (15) and which is controlled by an earth detection member (22) in the distribution socket (8)

Methodology Applied
Scientific EffectElectrical conductivity detection: Conduction (electrical)

Implementation Method 2

the evacuation component (18) is connected to the connection element (15) and arranged to evacuate towards the earth terminal (14) a lightning current resulting from the overvoltage

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

the first switch (20) is controlled by an earth detection member (22) in the distribution socket (8) so as to close the first switch (20) in presence of earth and to open the first switch (20) in the absence of earth

Methodology Applied
Scientific EffectElectrical switching: Conduction (electrical)

Data Source

PatentEP2847840B1Device for protecting at least one electrical apparatus against overvoltage generated by a lightning strike
Publication Date: 2017.07.05 SAGEMCOM BROADBAND SAS
  • EP2847840B1 patent drawingFigure 1
  • EP2847840B1 patent drawingFigure 2
  • EP2847840B1 patent drawingFigure 3

AI summary

The invention concerns a device for protecting at least one electrical apparatus (2) against overvoltage generated by a lightning strike, the device comprising a connection socket (7) for connecting the device to a distribution socket (8) of a power supply network and a member (6) for connecting the apparatus (2) to the connection socket (7), the connection socket (7) comprising a connection element (15) for connection to an earth terminal (14) of the distribution socket (8) and the device comprising a discharge component (17) connected to the connection element (15) and arranged to discharge to the earth terminal (14) a lightning current resulting from the overvoltage. According to the invention, the device comprises a first switch (20) which is mounted between the discharge component (17) and the connection element (15) and which is controlled by an earth detection means (21, 22 and 24) in the distribution socket (8) in such a way as to close the first switch (20) in the presence of earth and to open the first switch (20) in the absence of earth.