HVDC Switch Device Voltage-Dependent Bleeder Resistor
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Solution Overview
Problem
Switching devices designed for lower voltage levels are not suitable for HVDC systems due to high capacitive loads, leading to cost disadvantages when using higher voltage level devices, and existing solutions fail to effectively manage overvoltage situations in HVDC transmission systems.
Innovation Solution
A switch device with a selected bleeder resistor that responds before others in an overvoltage situation, reducing its resistance and shifting voltage distribution across series-connected switches, avoiding restrikes and unequal energy input by using a control capacitor to ensure the selected bleeder resistor handles a larger partial voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If switching devices designed for lower voltage levels are used in HVDC systems, then cost is reduced, but the devices are not suitable due to high capacitive loads
Solution Approach 1:
The patent changes the electrical parameters of the bleeder resistors, specifically making them voltage-dependent with different response voltages. This allows the switching device to handle high capacitive loads in HVDC systems by dynamically adjusting resistance based on voltage conditions, enabling lower voltage level devices to operate reliably in high voltage environments
2Reliability
If higher voltage level switching devices are used in HVDC systems, then reliability is improved, but cost increases due to design specifications
Solution Approach 1:
By implementing voltage-dependent bleeder resistors with specific response voltage characteristics, the patent enables lower voltage level switching devices to achieve the reliability of higher voltage level devices when used in HVDC systems, thereby reducing cost while maintaining suitability
3Ease of manufacture
If all bleeder resistors have the same response characteristics, then manufacturing is simplified, but unfavorable switching cases occur where one bleeder resistor responds alone and experiences greatest energy input
Solution Approach 1:
The patent applies different response voltage characteristics to different bleeder resistors, creating local differentiation in their electrical properties. This ensures that during overvoltage situations, multiple bleeder resistors respond in a controlled sequence rather than simultaneously or with one dominating, preventing unfavorable switching cases and unequal energy distribution
Solution Approach 2:
The patent introduces asymmetry in the response voltages of the bleeder resistors, where each resistor has a specifically designed response voltage that is lower than the others. This asymmetric design prevents any single bleeder resistor from bearing the full energy load during switching operations, improving overall system reliability
4Reliability
If bleeder resistors have different response voltages, then switching performance is improved by preventing single-resistor response, but device complexity increases
Solution Approach 1:
The patent manages device complexity by systematically varying only the response voltage parameter of the bleeder resistors while maintaining other characteristics uniform. This controlled parameter differentiation achieves improved switching performance through preventing single-resistor response scenarios, while the variation remains manageable and designable
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
This configuration prevents unfavorable switching cases where only one bleeder resistor responds, reducing the likelihood of restrikes and energy overload, thereby enhancing the switch device's performance and safety in HVDC systems.
Implementation Method 1
a voltage-dependent bleeder resistor being connected electrically in parallel with each of the switches, which when a predetermined response voltage is exceeded reduces its electrical resistance
Implementation Method 2
a control capacitor is connected in parallel with the switch that is in parallel with the other bleeder resistor or one of the other bleeder resistors, which shifts the voltage distribution across the series-connected switches in such a way that at the selected bleeder resistance is always present a larger partial voltage
Data Source
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AI summary
The invention relates to a switch device (110, 210, 310, 410, 510) having at least two switches (120, 220, 320, 420, 520, 130, 230, 330, 430, 530) which are connected in series and which can be jointly switched on or switched off in order to switch on and switch off the switch device (110, 210, 310, 410, 510), wherein in each case one voltage-dependent discharge resistor (140, 240, 340, 440, 540, 150, 250, 350, 450, 550) is connected electrically in parallel to each of the switches (120, 220, 320, 420, 520, 130, 230, 330, 430, 530), said discharge resistor reducing its electrical resistance value when a prespecified response voltage is exceeded. According to the invention, provision is made for one of the discharge resistors (140, 240, 340, 440, 540) to be a selected discharge resistor which, when all of the switches (120, 220, 320, 420, 520, 130, 230, 330, 430, 530) of the switch device (110, 210, 310, 410, 510) are jointly switched off in the event of an overvoltage situation, always responds before the other discharge resistor or resistors (150, 250, 350, 450, 550) and reduces its resistance value by reducing the voltage which is applied to the associated switch (120, 220, 320, 420, 520, 130, 230, 330, 430, 530).