Composite Electrode Surge Arrester with Embedded Auxiliary Trigger

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Solution Overview

Problem

Current low voltage surge arresters with graphite electrodes suffer from unstable trigger electrodes due to mechanical contact issues and high sparkover voltage, leading to poor protection and miniaturization challenges.

Innovation Solution

The use of metallic conductor auxiliary electrodes embedded within non-metallic main electrodes, combined with flexible insulators, enhances spark gap ignition and arc extinction, providing a stable and efficient surge protection with reduced vibration and increased follow current breaking capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If graphite electrodes with mechanical contact trigger electrodes are used, then the structure is simple and cost is low, but the trigger electrode stability deteriorates due to contact breaks and oxidation

Engineering Contradiction:
Improvestructural simplicityVSAvoidtrigger electrode stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent replaces the mechanical contact trigger electrode system with an auxiliary electrode embedded directly in the graphite electrode, eliminating the needle-to-surface contact mechanism. This substitution of the triggering mechanism resolves the instability caused by mechanical contact breaks and oxidation while maintaining manufacturing simplicity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The auxiliary electrode is embedded within the graphite electrode material, creating a nested structure where the triggering element is contained within the main electrode body. This nesting eliminates the need for external mechanical contacts while maintaining structural simplicity and improving reliability.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Power

If multiple graphite spark gaps are stacked in series, then the flow capacity increases, but the sparkover voltage becomes too high and the device size increases

Engineering Contradiction:
Improveflow capacityVSAvoidnumber of spark gaps
Core Design Contradiction:
PowerVSQuantity of substance

Solution Approach 1:

The patent modifies the electrical parameters of the spark gaps by embedding auxiliary electrodes that create additional electric field concentration points. This changes the breakdown characteristics of each gap, reducing the sparkover voltage while maintaining the series stacking configuration for high flow capacity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The auxiliary electrodes are placed at specific locations within the graphite electrode structure to create localized field enhancement zones. This local modification optimizes the breakdown characteristics without requiring changes to the overall multi-gap configuration, maintaining flow capacity while reducing sparkover voltage.

Inventive Principle:
Principle #3Local quality

3Reliability

If the trigger contact points are made more robust, then the stability improves, but the device complexity and size increase

Engineering Contradiction:
Improvecontact stabilityVSAvoidtrigger mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent eliminates the mechanical needle contact trigger system entirely and replaces it with an embedded auxiliary electrode that provides electrical triggering through the electrode structure itself. This substitution reduces mechanical complexity while improving reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts the triggering function from the mechanical contact system and integrates it directly into the electrode structure through embedding. This separation of the triggering mechanism from the mechanical contact system simplifies the overall device while improving stability.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This configuration results in a low voltage surge arrester with improved stability, reduced sparkover voltage, and enhanced protection capabilities, enabling effective protection of electronic equipment against atmospheric and industrial overvoltages while maintaining a compact design.

Implementation Method 1

an auxiliary electrode (1) in metallic conductor... connected connection leg (8) for connection with a high voltage trigger circuit

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a flexible separation insulator (3), which resists a very high temperature

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

a reinforcement of the extinction of the electric arc thanks to its heat dissipation during the arc

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3432429B1Composite electrode for low-voltage surge arrester with multiple spark gaps in series
Publication Date: 2020.12.23 XIAMEN SET ELECTRONICS CO LTD
  • EP3432429B1 patent drawingFigure 1
  • EP3432429B1 patent drawingFigure 2-a
  • EP3432429B1 patent drawingFigure 2-b~2-c

AI summary

The present invention relates to series-connected multi-spark arresters with compound electrodes. Each spark gap stage consists of a main electrode (4) made of a non-metallic conductor or alloy, an auxiliary electrode (1) made of a metallic conductor, and a separating insulator (3) that is resistant to high temperatures. The final stage is closed by a main closing electrode (6). The auxiliary electrode (1) is in contact (7) with the main electrode (4) by being clamped on one side and is followed by the separating insulator (3) on the other. The main electrodes (4), auxiliary electrodes, and insulators (3) of all the stacked spark gaps are arranged between two clamping plates (2) which are locked by fasteners (5), and each of the connecting tabs (8) of the auxiliary electrodes (1) is oriented in the same direction.This invention offers very high discharge capacity, a low protection level (<1.5kV) for good protection of most electronic equipment, a high operating voltage (Uc can reach 500V AC), a Up/Un ratio <3, a high surge current extinguishing capacity (>6kA under 385V AC), and a small size. It overcomes the contact breakage that leads to internal damage and the high protection level of existing multi-spark surge arresters. The present low-voltage (<1500V) surge arrester is designed for protection against atmospheric and industrial overvoltages. It provides a new configuration for series-connected multi-spark surge arresters.