Gas-Insulated Neutral Point Device Structure Simplification

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing closed neutral point equipment requires multiple gas chambers, leading to complex structures and high costs, and is not suitable for overhead line connections due to grounded cable wire inlet ends.

Innovation Solution

A gas-insulated and metal-closed neutral point device with a simplified structure, featuring an arrester, isolating switch, and discharge gap, where the arrester and switch are vertically arranged with conductive and ground terminals, and an intermediate conductor connects them to the transformer neutral point, eliminating the need for separate supporting bases and additional cylinders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple gas chambers are used for closed neutral point equipment, then insulation performance is improved, but device complexity increases

Engineering Contradiction:
Improveinsulation performanceVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple gas chambers into a single shared gas chamber that houses the arrester, isolating switch, and discharge gap together. This consolidation maintains the insulation performance of separate chambers while eliminating the complexity of multiple sealed compartments and their associated sealing points, directly resolving the contradiction between insulation reliability and structural simplicity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single gas chamber serves multiple functions simultaneously: it provides insulation for all three components (arrester, isolating switch, discharge gap), acts as a common enclosure, and maintains a uniform SF6 gas environment throughout. This multi-functionality eliminates the need for separate specialized chambers for each component, reducing overall device complexity while preserving insulation performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple gas chambers are used for closed neutral point equipment, then insulation performance is improved, but manufacturing cost increases

Engineering Contradiction:
Improveinsulation performanceVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

By combining multiple gas chambers into one unified chamber, the patent reduces the number of sealing points, flanges, and gaskets required for assembly. This simplification directly lowers manufacturing costs while maintaining the insulation performance through the uniform SF6 gas environment and adequate spacing between components within the single chamber.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If cable wire inlet end is grounded, then safety is improved, but adaptability for overhead line connection deteriorates

Engineering Contradiction:
ImprovesafetyVSAvoidconnection adaptability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent segments the grounding function from the cable wire inlet end by providing a separate dedicated ground terminal for the discharge gap. This allows the cable wire inlet end to remain non-grounded (enabling overhead line connections) while the discharge gap maintains its grounding function through the separate terminal, thus resolving the contradiction between safety and adaptability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediate isolating switch between the cable wire inlet end and the ground connection. This intermediary component allows flexible configuration: it can isolate the cable side from ground for overhead line applications, or connect to ground for cable applications, thereby enabling both connection types while maintaining safety through proper grounding of protective devices.

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 solution reduces space occupation, lowers costs, enhances reliability, and allows for overhead line connections by simplifying the structure and ensuring safe performance, while maintaining functional requirements.

Implementation Method 1

a first insulating pillar and a second insulating pillar which are arranged parallel to each other, are respectively provided in a first gas chamber and a second gas chamber; the first insulating pillar and the second insulating pillar are respectively provided with a first conductive rod and a second conductive rod

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

a discharge gap, wherein the discharge gap comprises a neutral point connection side for conducting with the neutral point of the transformer, and a ground side for grounding

Methodology Applied
Scientific EffectElectrical discharge: Electric Arc

Data Source

PatentEP3823115B1Gas-insulated metal enclosed neutral point complete-set device
Publication Date: 2022.06.29 STATE GRID ZHEJIANG ELECTRIC POWER CO LTD
  • EP3823115B1 patent drawingFigure 1
  • EP3823115B1 patent drawingFigure 2
  • EP3823115B1 patent drawingFigure 3~4

AI summary

The present invention relates to a complete set of gas-insulated and metal-enclosed neutral point device. In the complete set of device, the arrester and the isolating switch are both closed structures arranged vertically; one of the arrester and the isolating switch is provided with a wire inlet cylinder at the top, the other is provided with an adaptive cylinder; an intermediate cylinder is provided between the wire inlet cylinder and the adaptive cylinder, and an intermediate conductor is provided in the intermediate cylinder; an adaptive conductor is provided in the adaptive cylinder; the intermediate conductor is connected to the arrester under the adaptive cylinder or to a top conductive terminal on the isolation switch through the adaptive conductor; the neutral point connection side of the discharge gap is fixed on a top of the wire inlet cylinder, the ground side of the discharge gap is electrically connected to the adaptive cylinder or is provided with a ground connection end, and a branch conductive structure is provided in the wire inlet cylinder. The above solution solves the problems that the existing complete set of closed neutral point equipment needs to be equipped with more gas chambers and thus the structure is relatively complicated and the cost is high.