Voltage Surge Protector with Thermal Disconnector
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Solution Overview
Problem
Existing voltage surge protection devices do not provide sufficient protection against short-circuit currents with energies below the tripping threshold, leading to potential material damage due to incorrect installation or surge arrestor impedance degradation.
Innovation Solution
Incorporating a thermal disconnector and optionally an electromagnetic disconnector in series with the surge arrestor, which includes a fuse element and arc extinguishing chamber to disconnect when short-circuit currents below the tripping threshold flow, and a mechanism to cause permanent opening of contacts when higher energy currents are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the disconnection device is calibrated to remain latched during electric surge currents of 10/350 or 8/20 type, then the device can discharge surge currents without permanent opening of contacts, but the device fails to provide sufficient protection when AC or DC short-circuit energy drops below the tripping threshold
Solution Approach 1:
The disconnection device is divided into two independent mechanisms: a thermal disconnection mechanism for low-energy short-circuits and an electromagnetic disconnection mechanism for high-energy surges. This segmentation allows each mechanism to be optimized for its specific function without compromising the other, resolving the contradiction between reliability and complexity.
Solution Approach 2:
The thermal disconnection mechanism is designed to activate only for low-energy short-circuits below the tripping threshold, while the electromagnetic mechanism handles high-energy surges. This partial action approach ensures that each mechanism operates only when needed, providing comprehensive protection without requiring both mechanisms to be constantly active, thus managing complexity while maintaining reliability.
2Reliability
If the tripping energy threshold is set high enough to prevent permanent opening during surge currents, then surge discharge is enabled, but protection against low-energy short-circuit currents becomes insufficient
Solution Approach 1:
A thermal disconnection mechanism acts as an intermediary between the surge arrestor and the disconnection device. This intermediary mechanism specifically targets low-energy short-circuit currents that would otherwise pass through without triggering the main electromagnetic disconnection, thereby preventing material damage while preserving surge discharge capability.
Solution Approach 2:
The system uses two different energy thresholds: a lower tripping threshold for the thermal disconnection mechanism targeting low-energy short-circuits, and a higher tripping threshold for the electromagnetic disconnection mechanism targeting high-energy surges. This dual-threshold parameter approach enables differentiated protection levels for different types of electrical faults.
3Object-affected harmful factors
If the disconnection device permanently opens contacts for all short-circuit currents, then protection against material damage is enhanced, but normal surge discharge operation is disrupted
Solution Approach 1:
The thermal disconnection mechanism provides partial protection by activating only for low-energy short-circuit currents below the main tripping threshold. This selective action prevents material damage from problematic low-energy short-circuits while leaving high-energy surge discharge operations unaffected, thus resolving the contradiction between damage prevention and functionality.
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
Effectively prevents material damage from short-circuit currents by disconnecting when currents are below the tripping threshold and ensuring permanent opening when currents exceed it, enhancing protection against both low-energy and high-energy surges.
Implementation Method 1
Said thermal disconnector is out of circuit when an electric arc is switched between the first connecting electrode and the second connecting electrode. Disconnection of said disconnector is performed when AC or DC short-circuit electric currents having a lower energy than a tripping energy threshold is flowing through the latter
Implementation Method 2
an arc extinguishing chamber comprising at least one conducting separator secured inside the side wall to define two pressure relief volumes
Data Source
AI summary
A voltage surge protection device comprising a disconnection device with electric contacts said disconnection device comprising a first connecting electrode electrically connected with a first connecting strip, a second connecting electrode electrically connected with a second connecting strip, and a third switching electrode electrically connected to the second connecting strip. The protection device comprises a surge arrestor connected in series with a thermal disconnector between the third movable arc switching electrode and the second connecting strip. Said thermal disconnector comprises at least one fuse element extending between a first and second conducting radial wall of an arc extinguishing chamber, said arc extinguishing chamber comprising at least one conducting separator.