Three-Pole Lightning Arrestor Integrated into Residential Gateway
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Solution Overview
Problem
Residential gateways and similar electronic devices face challenges in protecting against lightning strikes, especially when not connected to ground, as existing solutions are inadequate in handling overvoltages exceeding 1.5 kV common mode, leading to damage to Ethernet ports and other components.
Innovation Solution
An electronic device architecture featuring a front end coupled to the line through an isolation transformer, a three-pole gas spark gap for overvoltage cancellation, and a capacitive or resistive divider component to create a voltage divider bridge, which limits the voltage imposed on the device's mass during a lightning strike, protecting components downstream and reducing the risk of damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gateway is not connected to ground or the connection is poor, then the front components are protected from overvoltage, but the Ethernet port components are damaged due to potential reaching 6.0 kV
Solution Approach 1:
The invention divides the protection function into two independent parts: a first protection means (gas discharge tube) for protecting front components from overvoltage on the DSL line, and a second protection means (varistor) for protecting ground-connected components from potential rise. This segmentation allows each protection means to be optimized for its specific protection target without interfering with the other.
Solution Approach 2:
The invention introduces an intermediary element (the second protection means/varistor connected between electrical ground and the common point) that mediates the potential difference between ground and the DSL line during lightning strikes. This intermediary limits the potential rise on the ground side, thereby protecting ground-connected components without affecting the primary protection function.
2Ease of manufacture
If components are sized to withstand 1.5 kV common mode overvoltage, then the design meets standard protection requirements, but components are damaged when 6.0 kV overvoltage is imposed on ground
Solution Approach 1:
The protection system is segmented into two independent protection means, each handling a different aspect of lightning protection. The first means handles line-to-ground overvoltage, while the second means handles ground potential rise. This allows components to be sized according to standard requirements while providing enhanced overall protection.
Solution Approach 2:
The second protection means (varistor) acts as a pre-prepared cushioning element that limits ground potential rise before it can damage ground-connected components. By being connected between ground and the common point, it proactively limits the voltage stress on Ethernet port components during lightning events.
3Device complexity
If a single ground connection is used for all components, then the circuit is simple, but all ground-connected components are exposed to the same potential rise during lightning strikes
Solution Approach 1:
The second protection means serves as an intermediary element that decouples the ground potential rise from ground-connected components. By connecting between the common point and electrical ground, it creates a voltage-limiting interface that protects multiple ground-connected components without requiring complex individual protection for each component.
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
Effectively protects components from lightning-induced overvoltages by controlling voltage distribution between the telephone line and electrical ground, ensuring that even in the absence of a ground connection, the device's components remain within safe voltage limits, preventing damage and ensuring nominal operation performance.
Implementation Method 1
an evacuation component such as a three-pole gas spark gap, connected to the conductive elements of the line and which becomes conductive in the event of an overvoltage due to a lightning strike on the line, to cancel this overvoltage by establishing a current flowing from the line to ground
Implementation Method 2
a divider component of the capacitive and/or resistive type interposed between the evacuation component and the electrical ground, to constitute, with the power supply unit and/or one or more of the additional components, a divider bridge thanks to which the voltage imposed on the mass of the device in the event of lightning is lower than the overvoltage undergone by the conductive elements of the line
Implementation Method 3
a front end coupled to the line through an isolation transformer
Data Source
Figure 1
Figure 2a~3
Figure 4
AI summary
The invention relates to an electronic apparatus 1 supplied by a supply block 10 connected to an electrical network of the mains type, intended to be connected to a transmission line 5, 3 comprising two conducting elements 6, 7 and to a terminal 9 for transferring data between the line 5, 3 and the terminal 9. According to the invention, this apparatus comprises: - a front component 20 coupled to the line through an isolation transformer 8; - various additional components 8, 30, C1, C2, C5 linked to an electrical earth 15 of the apparatus 1; - an evacuation component 11 such as a three-pole gas-based spark arrestor, connected to the conducting elements 6, 7 of the line and which becomes passing in the event of an overvoltage due to a lightening strike on the line 5, 3, so as to cancel this overvoltage by establishing a current flowing from the line to the earth 15 in such a way as to protect the components situated downstream of this protection such as the transformer 8 or the front component 20; - a divider component of capacitive and/or resistive type C4 interposed between the evacuation component 11 and the electrical earth 15, so as to constitute, together with the supply block and/or one or more of the additional components, a divider bridge by virtue of which the voltage imposed on the earth 15 of the apparatus in the event of lightning is below the overvoltage experienced by the conducting elements 6, 7 of the line so as to also protect the additional components 8, 30, C1, C2, C5.