Field-Controlled Composite Insulator for High Voltage
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Solution Overview
Problem
Composite insulators face local field disturbances and excessive field strengths due to inhomogeneous electrical field distribution and dirt accumulation, leading to corona discharges and material degradation.
Innovation Solution
A field control layer with varying particle proportions, composed of resistive or capacitive materials like microvaristors and dielectric fillers, is applied to the insulator core, surrounded by a protective layer, to evenly distribute the electric field and prevent local field disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a semiconducting field control layer is applied to the insulator core, then local field disturbances and excessive field strengths are reduced, but metal particles and dirt particles accumulate on the semiconducting layer and cause local field strength increases
Solution Approach 1:
The patent applies a composite protective layer containing ceramic particles (such as aluminum oxide or silicon oxide) embedded in a polymer matrix over the semiconducting field control layer. This composite structure provides both electrical field control and particle resistance, preventing metal and dirt particles from accumulating on the semiconducting layer while maintaining field distribution uniformity.
Solution Approach 2:
The protective layer is specifically applied in regions where particle accumulation is most problematic, such as near fittings and shield transitions. This localized protection maintains the semiconducting properties where needed while preventing particle accumulation in critical areas, resolving the contradiction between field control and particle resistance.
2Object-generated harmful factors
If the field control layer contains high proportions of resistive particles, then corona discharges are suppressed, but the layer becomes highly resistive causing high voltage drops and potential flashovers
Solution Approach 1:
The patent varies the particle concentration and type throughout the field control layer, creating zones with different resistivity. Near the insulator ends where corona discharge is most severe, higher concentrations of resistive particles are used. In central regions, lower concentrations maintain lower overall resistivity, reducing voltage drops and preventing flashovers while still suppressing corona where needed.
Solution Approach 2:
The field control layer is divided into multiple sections with different particle compositions and concentrations. This segmentation allows each section to be optimized for its specific electrical field conditions, suppressing corona discharge in high-stress areas while maintaining energy efficiency in lower-stress regions.
3Reliability
If geometric field control by rounding corners and edges is applied, then excessive field strength at transitions is reduced, but the structural design complexity increases
Solution Approach 1:
The patent introduces a semiconducting field control layer as an intermediary between the insulator core and the external environment. This layer provides field control through its electrical properties rather than geometric modifications, avoiding the need for complex rounded transitions while still preventing excessive field strength at sharp corners and edges.
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 effectively reduces power losses and prevents premature aging by minimizing glow discharges, corona discharges, and flashovers, enhancing the insulator's durability and performance, especially at high voltages.
Implementation Method 1
the proportion of the particles influencing the electric field varies over the length of the layer
Implementation Method 2
particles influencing the electric field of the insulator as a filler
Implementation Method 3
Outside the armature, the field control layer is surrounded by a protective layer
Implementation Method 4
local coverings or coatings made of insulating materials, for example plastics such as epoxy resins and polymers, with inclusions of dielectric and/or ferroelectric materials are applied as field control layers
Implementation Method 5
rod or tube as the insulator core made of fiber-reinforced plastic
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The materials of an insulator are greatly stressed by the inhomogeneous distribution of the electric field across the surface thereof. One of the causes is the design configuration of the insulator. The field strength changes particularly in the region of the fittings due to the transition from the insulating materials of the shields and the insulator core to a metal material, due to the transition from the ground potential at the cross arm, or to the conductor potential at that location, where the conductor cables are attached. A further cause is the deposit of dirt, which is stress affecting an insulator overall. The invention therefore provides that a field control layer (3) is disposed between the core (2) and the protective layer (4) in at least one section (15; 16) of the insulator (1; 10), said control layer comprising particles as the filler, which influence the electric field of the insulator.