Encapsulated Switchgear Using Two-Phase Dielectric Insulation
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Solution Overview
Problem
Conventional medium or high voltage encapsulated switchgears face challenges with complex and expensive gas pressure measurement equipment, mechanical stress due to overpressure, and environmental impact from conventional insulation gases, leading to high costs and complex housing designs.
Innovation Solution
A switchgear design utilizing a dielectric compound with a boiling point above -5°C, allowing a two-phase system that maintains insulation performance even with gas leakage, eliminating the need for complex pressure measurement equipment and enabling a simpler, cost-effective, and environmentally friendly solution by using a fluoroketone with high vapour pressure, such as dodecafluoro-2-methylpentan-3-one, which is non-toxic and has a low global warming potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional insulation gases with high insulation performance are used, then insulation performance is improved, but environmental impact increases due to high global warming potential
Solution Approach 1:
The patent changes the physical-chemical parameters of the insulation medium by using a dielectric liquid with a boiling point above -5°C instead of conventional gaseous insulation media. This parameter change allows the system to maintain high insulation performance while using environmentally friendly substances with low global warming potential, thus resolving the contradiction between insulation performance and environmental impact
Solution Approach 2:
The patent utilizes phase transitions by employing a dielectric liquid that can evaporate to form insulation gas. The liquid phase serves as a reservoir that continuously replenishes the gas phase, ensuring stable insulation performance. This phase transition mechanism allows the system to achieve both high reliability and environmental compatibility, as the liquid can be chosen to have low GWP while maintaining effective insulation through its vapor
2Reliability
If gas pressure measurement equipment is used to monitor insulation gas, then insulation performance is maintained, but device complexity and cost increase
Solution Approach 1:
The dielectric liquid serves a dual function: it acts as both the insulation medium (when evaporated) and as a self-monitoring reservoir. By simply observing the liquid level in the reservoir, the system automatically indicates whether sufficient insulation medium is present, eliminating the need for complex pressure measurement equipment while maintaining insulation performance
Solution Approach 2:
The patent replaces the mechanical/electronic gas pressure measurement system with a simple visual liquid level indicator. This substitution eliminates complex sensors, transducers, and measurement circuits, reducing device complexity and cost while maintaining the ability to monitor insulation performance through direct visual inspection of the liquid reservoir level
3Measurement precision
If overpressure is applied to the housing, then pressure measurement precision is improved, but mechanical stress on housing increases leading to gas leakage risk
Solution Approach 1:
The patent eliminates the overpressure requirement by using a two-phase system where liquid evaporates to maintain gas pressure. The liquid reservoir automatically regulates the gas pressure through equilibrium vapor pressure, avoiding the need for high overpressure that would stress the housing. This phase transition mechanism provides stable insulation performance without compromising housing integrity
Solution Approach 2:
The patent changes the operating pressure parameter from high overpressure (100-500 mbar) to near-ambient pressure by using the vapor pressure of the dielectric liquid. This parameter change eliminates the mechanical stress on the housing while maintaining sufficient insulation performance, thereby reducing gas leakage risk without sacrificing measurement or insulation precision
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 provides a safe, cost-effective, and environmentally friendly encapsulated switchgear with maintained insulation performance without immediate operation interruption, allowing for easy monitoring of insulation gas concentration and simplifying maintenance by visual inspection of a liquid phase indicator, reducing the need for evacuation and reintroduction procedures.
Implementation Method 1
using a dielectric compound with a boiling point above -5°C, allowing a two-phase system that maintains insulation performance even with gas leakage
Implementation Method 2
using a fluoroketone with high vapour pressure, such as dodecafluoro-2-methylpentan-3-one
Data Source
Figure 1
AI summary
The present invention relates to an encapsulated switchgear comprising a housing (4) defining an insulating space (6) and an electrical active part (8; 9, 11a, 11b, 11c) arranged in the insulating space (6), said insulating space (6) comprising an insulation medium.. The switchgear is characterized in that the insulation medium comprises a dielectric compound having a boiling point of above -25°C.