Sealed SPD Module Assembly for Varistor Heat Dissipation
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Solution Overview
Problem
Surge protective devices (SPDs) face challenges in effectively managing transient overvoltages and surge currents from sources like lightning strikes, particularly in protecting electronic equipment connected to wind turbines, photovoltaic modules, and residential/commercial facilities, as existing solutions often fail to provide comprehensive and reliable overvoltage protection.
Innovation Solution
A modular SPD assembly module featuring a polymeric outer enclosure with an environmentally sealed SPD chamber containing varistor and gas discharge tube (GDT) components, along with a meltable member for forming an electrical short circuit path during overvoltage events, ensuring robust and reliable protection against surges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a varistor member is used for surge protection, then protection effectiveness against transient overvoltages is improved, but the device may overheat and fail during operation
Solution Approach 1:
A thermal conductor member is introduced as an intermediary between the varistor member and the electrode members. This thermal conductor has higher thermal conductivity than the varistor material, acting as a heat transfer bridge that conducts heat away from the varistor during surge events, preventing overheating while maintaining electrical connection for surge protection functionality
Solution Approach 2:
The thermal conductivity parameter of the connection path is changed by replacing the varistor-to-electrode interface (lower thermal conductivity) with a dedicated thermal conductor member (higher thermal conductivity). This parameter change enables more efficient heat dissipation from the varistor during operation, allowing the device to handle higher surge currents without thermal failure
2Object-affected harmful factors
If the SPD chamber is environmentally sealed, then protection against environmental contaminants is improved, but heat dissipation from internal components may be reduced
Solution Approach 1:
The thermal conductor member serves as a thermal pathway intermediary that conducts heat from the varistor through the electrode members to external heat sinks (such as terminal blocks or mounting surfaces). This creates an internal heat management system that operates independently within the sealed enclosure, allowing effective heat dissipation without requiring thermal connection to the external environment
Solution Approach 2:
The SPD module structure itself (electrode members, terminal blocks, mounting surfaces) serves as the heat dissipation pathway. The thermal conductor member directs heat to these existing structural elements, which naturally dissipate heat to the surrounding air within the sealed enclosure, eliminating the need for dedicated external heat sinks or active cooling systems
3Ease of operation
If a modular SPD assembly is designed, then ease of installation and replacement is improved, but device complexity increases
Solution Approach 1:
The surge protective device is segmented into a modular SPD module that can be independently manufactured, tested, and replaced. The SPD module contains the varistor member, thermal conductor member, and electrode members as a self-contained unit with external terminals, allowing it to be installed or replaced as a single component without disturbing the enclosure or other system elements, simplifying field maintenance while containing complexity within the module itself
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 enhanced protection against transient overvoltages and surge currents by utilizing a varistor and GDT within an environmentally sealed module, ensuring reliable operation and preventing overheating, thus safeguarding connected equipment from damage.
Implementation Method 1
a varistor member formed of a varistor material and electrically connected between the first and second electrode members
Implementation Method 2
a gas discharge tube (GDT) disposed in the SPD chamber and connected in electrical series with the varistor member
Implementation Method 3
the meltable member is responsive to heat in the overvoltage protection device to melt and form an electrical short circuit path between the first and second electrode members
Data Source
AI summary
A surge protective device (SPD) assembly module includes a polymeric outer enclosure, an SPD module, a first terminal, and a second terminal. The polymeric outer enclosure defines an enclosed, environmentally sealed enclosure chamber. The SPD module is disposed in the enclosure chamber. The SPD module defines an environmentally sealed SPD chamber and includes: first and second electrically conductive electrode members; and a varistor member formed of a varistor material and electrically connected between the first and second electrode members. The varistor member is disposed in the SPD chamber between the first and second electrode members. The first terminal is electrically connected to the first electrode member and extending out from the outer enclosure. The second terminal is electrically connected to the second electrode member and extending out from the outer enclosure.