Overvoltage Protection Element with Pressure-Sensitive Switch
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Solution Overview
Problem
Existing overvoltage protection elements face challenges in reliably disconnecting fault currents due to aging surge arresters, leading to arcs that can cause damage and go unnoticed, resulting in potential reactivation of defective components.
Innovation Solution
An overvoltage protection element with a pressure-sensitive switch, thermal switch, and spark gap is designed to short-circuit electrical conductors upon increased pressure from arcs, triggering upstream overcurrent protection and preventing reactivation of defective components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a metallic housing is used to contain arcs and short-circuit fault currents, then the housing provides mechanical protection and contains fault energy, but the arc behavior becomes undefined and internal damage occurs without visible external signs
Solution Approach 1:
A pressure-sensitive switch is introduced as an intermediary between the arc event and the external signaling system. The switch detects pressure waves generated by arcs through the housing wall and converts them into electrical signals that can trigger visible indicators or alarms, providing reliable fault detection without compromising the protective function of the metallic housing
Solution Approach 2:
The pressure-sensitive switch creates a feedback mechanism that monitors the internal state of the housing continuously. When an arc generates pressure waves, the switch detects these changes and provides feedback signals to indicate fault conditions, enabling real-time monitoring and immediate response to internal damage
2Reliability
If thermal disconnection devices are used to disconnect aged varistors, then functioning varistors are protected, but the devices cannot respond quickly enough to high-power arcs from overloaded surge arresters
Solution Approach 1:
The slow thermal-mechanical disconnection system is replaced with a pressure-sensitive electrical switching system. Pressure waves from arcs trigger the switch electronically, providing near-instantaneous detection and response compared to the gradual thermal expansion mechanism of traditional thermal disconnection devices
Solution Approach 2:
The detection parameter is changed from temperature (slow response) to pressure wave detection (fast response). Pressure waves propagate through the housing almost instantaneously when an arc occurs, enabling the pressure-sensitive switch to detect faults much faster than thermal devices can respond to temperature changes
3Device complexity
If disconnecting devices are designed for low switching capacities, then the device structure remains simple, but arcs cannot be extinguished when high currents are already flowing
Solution Approach 1:
The arc extinction function is extracted from the disconnecting device and assigned to the pressure-sensitive switch system. The switch simply detects pressure waves and triggers protective actions without attempting to extinguish arcs directly, allowing the device to handle high currents while maintaining structural simplicity
Solution Approach 2:
Pressure waves serve as an intermediary that transfers energy from the high-power arc to the low-power switching mechanism. The pressure-sensitive switch detects these waves and triggers protective devices, enabling the simple disconnecting device to effectively handle arc situations without needing complex arc extinction capabilities
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
Ensures safe and reliable disconnection of fault currents, preventing damage and ensuring the overcurrent protection is triggered promptly, even in cases of defective surge arresters, thus maintaining system safety and preventing reactivation of faulty components.
Implementation Method 1
the thermal switch (14) is thermally connected to the surge arrester (3), so that when the surge arrester (3) heats up, i.e. there is an increase in temperature
Implementation Method 2
the spark gap (15) ignites, so that an increase in pressure occurs in the housing (1)
Implementation Method 3
a pressure-sensitive switch (4) for short-circuiting the electrical conductors (2) is arranged in the housing (1)
Data Source
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AI summary
The subject matter of the invention is an overvoltage protection element with a housing (1) and at least two electrical conductors (2) passing into the housing (1) for electrically connecting the overvoltage protection element, wherein a surge arrester (3) for limiting an overvoltage of the electrical conductors (2) and a pressure-sensitive switch (4) for short-circuiting the electrical conductors (2) are arranged in the housing (1). According to the invention, therefore, an overvoltage protection element is provided which, even in the event of a defective surge arrester (3), reliably and safely short-circuits the electrical conductors (2) when an arc is formed in the housing (1), with the result that overcurrent protection, for example a fuse, which is preferably connected upstream of the overvoltage protection element, can be triggered.