Gas-Tight Surge Arrester With Optimized Electrode Geometry
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Solution Overview
Problem
Conventional gas-filled surge arresters are limited to response voltages of up to 10kV, making them unsuitable for protecting medium-voltage transformers against high overvoltages such as those caused by lightning strikes, and the ambient condition-dependent response voltage of air spark gap surge arresters is difficult to stabilize.
Innovation Solution
A gas-tight surge arrester design with pin-shaped electrodes and a specific geometry relationship between electrode spacing and wall spacing, where the electrode spacing is equal to or less than twice the wall spacing, creating a gas-tight discharge space that ensures reliable ignition only at predetermined high response voltages, independent of ambient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional gas-filled surge arresters are used, then the structure is simple and reliable, but the response voltage is limited to up to 10kV
Solution Approach 1:
The patent changes the geometric parameters of the discharge space, specifically the relationship between electrode spacing (s) and wall spacing (a), defining a new parameter ratio s/a ≤ 2. This parameter optimization enables the discharge space to withstand higher voltages while maintaining reliable arc discharge, thereby extending the response voltage capability beyond conventional 10kV limits
2Reliability
If air spark gap surge arresters are used, then high response voltages can be achieved, but the response voltage depends on ambient conditions
Solution Approach 1:
The patent replaces the air environment with an inert or controlled gas atmosphere inside the sealed discharge space. This eliminates the dependence on ambient air conditions (humidity, temperature, pressure) that affect air spark gap performance, while the optimized geometry ensures reliable discharge at the desired high voltage levels
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 design achieves response voltages well above operating voltages, preventing unwanted ignitions and ensuring reliable protection for medium-voltage transformers against overvoltages up to 30kVrms, with response voltages exceeding 10kV and maintaining reliable ignition behavior.
Implementation Method 1
They work according to the gas-physical principle of arc discharge, whereby an arc forms in the gas-tight discharge chamber within nanoseconds after the arrester response voltage, referred to as response voltage or ignition voltage for short, has been reached.
Implementation Method 2
The discharge space is filled with gas. The overvoltage is reduced by the automatic ignition of the gas discharge.
Data Source
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AI summary
A surge arrester includes a gas-tight discharge chamber that is formed by at least one insulating body and two electrodes. The electrodes extend into the discharge chamber and include an electrode spacing with respect to one another and a wall spacing with respect to the insulating body inner wall. The electrode spacing is equal to twice the wall spacing or is less than twice the wall spacing.