Surge Arrester Module Coupling Structure for Stable Contact Pressure

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Solution Overview

Problem

Conventional surge arresters face issues with internal defects in insulating materials leading to partial discharges and loss of contact pressure due to weak external threads and potential loosening of nuts, resulting in functional failures.

Innovation Solution

A surge arrester module using insulating rods with metal sleeves and interlocking portions to securely attach to electrodes, providing improved strength and reliability, reducing the risk of partial discharges and facilitating easy assembly and maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If insulating loops are formed by wet-winding process, then the surge arrester can be assembled, but internal defects such as large delaminations, bubbles and voids occur causing partial discharges

Engineering Contradiction:
Improvemanufacturing processVSAvoidpartial discharge risk
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent changes the manufacturing process parameter from wet-winding to pultrusion process. This parameter change fundamentally improves the internal quality of the insulating material by eliminating the formation of delaminations, bubbles and voids that occur in wet-winding, thereby reducing partial discharge risks while maintaining manufacturing feasibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structure by combining insulating material with embedded metal reinforcement elements (such as steel wires or mesh) within the pultruded insulating rod. This composite approach enhances both the mechanical strength and electrical performance, preventing partial discharges while maintaining ease of manufacture

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If insulating rods are machined with external threads and connected to electrodes by nuts, then the assembly can be constructed, but the external threads are weak and teeth break easily resulting in loss of prestressing force

Engineering Contradiction:
Improveassembly capabilityVSAvoidthread strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent extracts the weak external threads from the insulating rod design and replaces them with an internal threading system where metal reinforcement elements provide the threading functionality. This separation allows the insulating material to maintain its integrity while the metal components provide the mechanical strength for connection

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses composite material structure with metal reinforcement elements (steel wires, mesh, or profiles) embedded within the insulating rod. These metal elements provide strong internal threading capabilities that resist breaking, while the insulating material maintains electrical isolation. The combination solves both the assembly requirement and the strength deficiency

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If nuts are used to connect insulating rods to electrodes, then the assembly can be fastened, but nuts may loosen due to creep of teeth causing functional failure

Engineering Contradiction:
Improvefastening capabilityVSAvoidconnection stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent extracts the external nut connection system and replaces it with an integrated internal threading system where metal reinforcement elements provide both the threading structure and the fastening function. This eliminates the separate nut component that is prone to loosening, while maintaining easy assembly through threaded connections

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces metal reinforcement elements as intermediary components that mediate between the insulating rod and the electrode connection. These intermediaries provide the mechanical strength and threading functionality, eliminating the need for external nuts that are susceptible to loosening from tooth creep

Inventive Principle:
Principle #24Intermediary (Mediator)

4Strength

If glue is applied between nuts and plastic teeth, then the connection can be strengthened, but plastic teeth are likely to break when assembly needs to be dismantled for maintenance

Engineering Contradiction:
Improveconnection strengthVSAvoidmaintainability
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The patent extracts the glued nut-tooth connection system and replaces it with a mechanical internal threading system using metal reinforcement elements. This eliminates the need for adhesive bonding, providing both strong connection and easy mechanical disassembly for maintenance without breaking the insulating material

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4369358A1Surge arrester module and surge arrester
Publication Date: 2024.05.15 HITACHI ENERGY LTD
  • EP4369358A1 patent drawingFigure 1
  • EP4369358A1 patent drawingFigure 2A~2B
  • EP4369358A1 patent drawingFigure 3A~3B

AI summary

The present disclosure provides a surge arrester module and a surge arrester including the surge arrester module. The surge arrester module includes a varistor stack, a pair of electrodes and a coupling assembly for coupling the pair of electrodes. The varistor stack includes multiple varistor blocks stacked along a longitudinal direction of the surge arrester module and is sandwiched the pair of electrodes. The coupling assembly includes at least one rod. Each rod includes a rod body extending in the longitudinal direction and at least one sleeve sleeved outside the rod body for attaching the rod to the electrode. The rod body is made of insulating material and includes a first interlocking portion. The sleeve is made of metal and includes a second interlocking portion adapted to fit with the first interlocking portion for preventing relative movement of the rod body and the sleeve in the longitudinal direction. The surge arrester module according to the present disclosure can offer the benefits of low risk of partial discharges, good functional reliability, high production rate and low cost.