Hybrid Voltage Limiter Bypass Layout to Prevent Dielectric Breakdown

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Solution Overview

Problem

Hybrid voltage limiters face issues with dielectric breakdown due to high current flow, leading to instantaneous meltdown of bolts and electrodes, especially when current is concentrated through small distances between components.

Innovation Solution

A hybrid voltage limiter design with a thyristor component and varistor component connected in parallel, featuring a bypass with a lower resistivity than the thyristor component, which directs current flow away from potential spark gaps, using a C-shaped bypass and aluminum or copper to minimize resistive loss and prevent dielectric breakdown.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a purely electronic trigger circuit is used, then switching speed and precision are improved, but circuit complexity and sensitivity to interference increase

Engineering Contradiction:
Improveswitching speedVSAvoidcircuit complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent combines electronic triggering circuitry with a thyristor component into a hybrid voltage limiter. The electronic circuit provides precise triggering control while the thyristor handles the high-power switching, merging the advantages of both electronic precision and semiconductor robustness to reduce overall circuit complexity while maintaining high switching speed.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The thyristor component acts as an intermediary between the low-power electronic triggering circuit and the high-voltage line. It receives precise triggering signals from the electronic circuit and translates them into high-power switching actions, isolating the sensitive electronic circuit from voltage spikes and interference while maintaining switching precision and speed.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If a purely electronic trigger circuit is used, then switching precision is improved, but sensitivity to interference and parasitic effects increases

Engineering Contradiction:
Improveswitching precisionVSAvoidsensitivity to interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The thyristor component serves as an intermediary that isolates the precise electronic triggering circuit from harmful voltage spikes and electromagnetic interference. The thyristor's inherent robustness protects the sensitive electronic circuit while maintaining the precision of the triggering signal transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The hybrid design provides beforehand cushioning by using the thyristor component to absorb and dissipate voltage spikes and interference before they can affect the electronic triggering circuit. This protective arrangement ensures the electronic circuit remains insensitive to interference while maintaining switching precision.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Loss of time

If a purely electronic trigger circuit is used, then response time is improved, but robustness and reliability decrease

Engineering Contradiction:
Improveresponse timeVSAvoidrobustness
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent merges the fast response capability of electronic circuits with the robustness of thyristor components. The electronic circuit provides rapid response time for detecting overvoltage conditions, while the thyristor component ensures reliable and robust operation in high-power environments, combining speed and reliability.

Inventive Principle:
Principle #5Merging (Combining)

4Speed

If a purely electronic trigger circuit is used, then switching speed is improved, but cost and complexity of protection against voltage spikes increase

Engineering Contradiction:
Improveswitching speedVSAvoidprotection circuit complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The thyristor component acts as a built-in intermediary that provides inherent protection against voltage spikes without requiring additional complex protection circuits. Its natural ability to handle high voltages and dissipate energy simplifies the overall protection scheme while maintaining fast switching speed.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 prevents dielectric breakdown by ensuring current flows through the bypass with lower resistivity, maintaining a compact structure and reducing the risk of spark gaps, thus enhancing the hybrid voltage limiter's operational reliability.

Implementation Method 1

a non-linear resistor, in particular a varistor

Methodology Applied
Scientific EffectNon-linear resistance: Electrical Resistance

Implementation Method 2

at least one thyristor component (20) with at least two switching states

Methodology Applied
Scientific EffectThyristor switching: Diode

Data Source

PatentEP4569525B1Hybrid voltage limiter comprising trigger electronic, thyristor component and a varistor
Publication Date: 2026.04.15 HITACHI ENERGY LTD
  • EP4569525B1 patent drawingFigure 1
  • EP4569525B1 patent drawingFigure 2
  • EP4569525B1 patent drawingFigure 3

AI summary

The invention relates to a hybrid voltage limiter. According to the invention, the hybrid voltage limiter (1) comprising a first electrode (14), a second electrode (15), trigger electronics (10), a thyristor component and a varistor component which comprises a varistor (9) and which is connected in parallel with the thyristor component, wherein the thyristor component is galvanically connected to the first electrode (14), the thyristor component is formed with two thyristors (5) connected in antiparallel, the gates of the antiparallel-connected thyristors (5) are connected to the trigger electronics (10) in such a way that a trigger signal of the trigger electronics (10) can be received, wherein the trigger electronics (10) are galvanically connected to the first electrode (14) and the second electrode (15), the thyristor component is galvanically connected to the second electrode (15) via a first resistivity, the thyristor component is galvanically connected to the second electrode (15) by a bypass (6) having a second resistivity, the first resistivity has a higher resistance value than the second resistivity, and the bypass (6) is connected to the second electrode (15) in such a way that a spark gap is avoided and the varistor component is galvanically connected to the first electrode (14) and the second electrode (15).