Neutral-Point Leakage Detection for Ground Fault Shock Prevention
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Solution Overview
Problem
Existing technologies fail to effectively prevent electric shocks and fires caused by leakage currents during electric leakage and ground fault, as they only detect and limit leakage currents to a dangerous level or operate when the leakage current exceeds a predetermined value.
Innovation Solution
An apparatus and method that detect leakage currents between power lines insulated from earth and the earth, limiting the detected leakage current to a dangerous level or cutting off the leakage current from flowing through human bodies or peripheral facilities, using failure detectors and a detection/recovery device to manage power supply.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If power lines are insulated from earth to prevent electric shock and fire, then safety is improved, but leakage current detection becomes more difficult
Solution Approach 1:
The patent introduces a neutral point as an intermediary reference between the insulated power lines and earth. This neutral point serves as a mediator that enables leakage current detection without requiring direct earth connection of the power lines, thus maintaining insulation safety while providing a detectable reference potential for leakage monitoring.
Solution Approach 2:
The patent replaces traditional direct earth connection (mechanical grounding) with insulation and neutral point reference system. Instead of mechanically connecting power lines to earth for safety, the system uses electrical insulation combined with neutral point potential reference, substituting the mechanical grounding approach with an electrical field-based detection method.
2Object-affected harmful factors
If leakage current is limited to dangerous current level, then safety is improved, but prevention of actual electric shock and fire is not achieved
Solution Approach 1:
The patent implements preliminary detection of leakage current through the neutral point before the current can reach dangerous levels. By continuously monitoring the potential difference between neutral point and earth, the system detects leakage early and triggers protective disconnection, preventing rather than merely limiting the harmful effects.
Solution Approach 2:
The patent establishes a feedback loop where leakage current detection through the neutral point reference continuously monitors system safety. When leakage is detected, the system provides feedback to disconnect protective devices, creating a closed-loop control system that actively prevents electric shock and fire rather than passively limiting current.
3Stability of the object's composition
If neutral line is commonly connected to ground line to maintain zero potential, then neutral line stability is improved, but leakage current detection capability is reduced
Solution Approach 1:
The patent segments the traditional combined neutral-ground connection into separate functional components: the neutral line maintains its potential stability through system design, while a separate neutral point reference system enables leakage detection. This segmentation allows both functions to operate independently without interfering with each other.
Solution Approach 2:
The patent adds a new dimensional reference (neutral point potential) beyond the traditional neutral-ground connection. By creating a separate potential reference dimension through the neutral point, the system enables leakage current detection without compromising the neutral line's potential stability maintained through conventional grounding.
Data Source
AI summary
An apparatus for preventing an electric shock and a fire according to the present invention includes one or more failure detectors that have one end electrically connected to at least one of two or more power lines insulated from earth with a resistance value greater than or equal to a predetermined ground resistance value and a first neutral point having a potential between voltages of the two or more power lines, and the other end electrically connected to the earth, in which the failure detector detects a leakage current by forming a current path for the leakage current flowing from the two or more power lines or the first neutral point to the earth. According to the present disclosure, it is possible to prevent the electric shock and the occurrence of the fire due to the leakage current.