Sealed Fluid-Insulated Diode Valve Assembly for Outdoor HVDC Use
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Solution Overview
Problem
High voltage direct current (HVDC) power transmission networks face challenges in protecting diode valves from environmental pollution and voltage reversal, which can lead to costly and space-intensive solutions, such as dedicated air-conditioned buildings, and require robust insulation to manage fault currents and prevent flashovers.
Innovation Solution
A diode valve assembly housed in a sealed enclosure filled with a high electrical breakdown strength fluid insulant, such as mineral oil or pressurized gas, with support structures and optional resistive elements, allowing for compact, cost-effective, and self-contained outdoor mounting, reducing the need for extensive civil works and monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diode valves are housed in dedicated air-conditioned buildings to protect from environmental pollution and voltage reversal, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies this principle by filling the sealed enclosure with sulfur hexafluoride (SF6) gas, an inert atmosphere that provides superior electrical insulation properties compared to air. This inert environment protects the diode valves from environmental pollution and voltage reversal effects, eliminating the need for complex air-conditioned buildings while maintaining high reliability.
Solution Approach 2:
The patent replaces expensive, complex infrastructure (air-conditioned buildings) with a simpler, self-contained sealed enclosure system. The SF6-filled enclosure acts as a disposable or replaceable unit that provides all necessary protection functions internally, reducing overall system complexity and cost.
2Reliability
If robust insulation is used to manage fault currents and prevent flashovers, then reliability is improved, but volume and cost increase
Solution Approach 1:
The patent changes the electrical parameter of the insulation medium by using SF6 gas instead of air or conventional solid insulation. SF6 has approximately 2.5 times the dielectric strength of air, allowing for significantly reduced insulation dimensions while maintaining the same level of protection against fault currents and flashovers.
Solution Approach 2:
The patent employs a gaseous insulation medium (SF6) under controlled pressure within a sealed enclosure, replacing bulky solid insulation structures. This pneumatic approach provides superior insulation properties in a compact form factor, reducing the volume required for fault current management and flashover prevention.
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 insulates and protects diode valves from environmental pollution and voltage reversal, minimizing space and cost requirements while maintaining reliable operation and fault current management in HVDC systems.
Implementation Method 1
the fluid insulant may have an electrical breakdown strength that is higher than an electrical breakdown strength of air at atmospheric pressure
Implementation Method 2
the gas insulant is pressurised above atmospheric pressure
Data Source
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AI summary
There is provided a diode valve assembly comprising a diode valve (30) and a sealed enclosure (32), the diode valve (30) including at least one diode, the or each diode housed inside the sealed enclosure (32), the sealed enclosure (32) filled with a fluid insulant (46).