Overvoltage Protection Triggering Circuit with Thermo-Sensitive Disconnector
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing overvoltage protection designs face issues with ineffective spark gap ignition due to low current impulse rise, leading to incomplete discharge and loss of protective function, and oscillation currents in triggering circuits that can extinguish the spark gap discharge.
Innovation Solution
The design incorporates a thermo-sensitive disconnector connected in series with a varistor and a gas discharge tube, ensuring reliable spark gap ignition and preventing damage from thermal overloading by disconnecting the triggering circuit from the distribution system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a gas discharge tube is used to directly excite the transformer primary winding, then the design is simple, but the auxiliary electrode of the spark gap will not activate if the rise of the pulse is low
Solution Approach 1:
A capacitor is introduced as an intermediary element between the gas discharge tube and the transformer primary winding. This capacitor integrates the current impulse, transforming its temporal characteristics to ensure sufficient rise rate for reliable spark gap activation while maintaining circuit simplicity
Solution Approach 2:
The patent changes the temporal parameters of the current impulse by using a capacitor to integrate the pulse from the gas discharge tube. This transformation modifies the rise time and amplitude characteristics, ensuring the auxiliary electrode receives sufficient current with adequate rise rate to reliably activate the spark gap
2Reliability
If a capacitive divider is used in the triggering circuit, then the spark gap activation is improved, but oscillation current flows through the secondary winding causing discharge extinguishing
Solution Approach 1:
The patent removes the capacitive divider element from the triggering circuit, extracting the source of oscillation currents. Instead, it uses a simpler capacitor-integration approach that achieves reliable spark gap ignition without generating harmful oscillation currents that would cause discharge extinguishing
Solution Approach 2:
The patent converts the potentially harmful oscillation currents into beneficial integrated current pulses by using a capacitor to smooth and shape the current waveform. This transformation turns what would be disruptive oscillations into controlled, reliable triggering signals that ensure consistent spark gap activation without discharge extinguishing
3Reliability
If a combined divider with varistor and capacitor is used, then some disadvantages are eliminated, but oscillation character of current still remains
Solution Approach 1:
The patent extracts and removes the varistor element from the triggering circuit, simplifying the structure while maintaining protective function. The remaining capacitor-based integration circuit provides sufficient current shaping without generating oscillation currents, achieving both reliability and simplicity
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 enhances the triggering ability of the overvoltage protection circuit, ensuring reliable operation and preventing damage to the entire protection system by disconnecting during thermal overloading, thus maintaining effective protection against overvoltages.
Implementation Method 1
activating a gas discharge tube with an overvoltage impulse
Implementation Method 2
the discharge between the first main electrode and the second main electrode of the spark gap
Implementation Method 3
one end of which is connected in series to a capacitor, the other end of which is connected to the second input terminal
Implementation Method 4
a first varistor, a second varistor, a resistor and a capacitor, connected in series between the first input terminal and the primary winding
Implementation Method 5
the other end of which is connected in series to a transformer, one end of the primary winding of which is connected to the gas discharge tube
Implementation Method 6
a thermo-sensitive disconnector, coupled with a thermal coupling to the second varistor
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The design of the triggering circuit (1) of the overvoltage protection connected in three poles to the spark gap (4) of the overvoltage protection, provided with input terminals I (2) and II (3), comprising an auxiliary electrode (7) of the spark gap connected in series with varistor I (8) and one end of the secondary winding (14) of the transformer (13), the other end of which is connected to main electrode II (6) of the spark gap (4) and input terminal II (3), whereas one end of the primary winding (15) of the transformer (13) is connected in series to a gas discharge tube (10), varistor II (9), resistor (11) and capacitor (12), connected to the other end of the primary winding (15) of the transformer (13), connected to input terminal II (3), whereas the junctor connecting varistor II (9) to the resistor (11) is interconnected with the junctor, connecting input terminal clamp I (2) with main electrode I (5) of the spark gap (4). The advantageous design of the triggering circuit (1) of the overvoltage protection provides a thermo- sensitive disconnector (17), thermally coupled (16) to varistor II (9), which is either connected in series to varistor II (9), or is connected in a junctor between the junction connecting varistor II (9) to the resistor (11) and the junction connecting input terminal I (2) to main electrode I (5) of the spark gap (4), or the thermo-sensitive disconnector (17) is connected between the primary winding (15) of the transformer (13) and the gas discharge tube (10).