Gas-Insulated High-Voltage Switch Piston Restoring Force
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Solution Overview
Problem
High-voltage switches face challenges in efficiently interrupting large, asymmetric short-circuit currents, leading to excessive contact erosion and contamination due to high arc voltage and energy exchange, which reduces reliability and service life.
Innovation Solution
A gas-insulated high-voltage switch design featuring a contact arrangement with arcing contacts supported by a pretensioned spring and a piston/cylinder system, where the arcing zone communicates with the piston/cylinder system to generate a restoring force that supports the spring's repelling force, reducing the distance between contacts and preventing high arc voltage, and includes a piston rod and exhaust duct to manage arc gas pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pretensioned spring is used to support the arcing contact and generate contact force, then reliable contact closure is achieved, but during switch-off the spring alone cannot prevent excessive contact separation distance and high arc voltage
Solution Approach 1:
The patent combines the pretensioned spring with a piston/cylinder system to create a hybrid restoring force mechanism. The spring provides initial contact force and the piston system amplifies this force during switch-off by utilizing compressed arc gas pressure, resolving the contradiction between maintaining reliable contact closure and preventing excessive contact separation.
Solution Approach 2:
The invention introduces a piston/cylinder system that utilizes the compressed arc gas pressure generated during contact separation. This pneumatic mechanism converts the arc gas pressure into additional restoring force, supplementing the spring force and preventing excessive contact separation distance and high arc voltage.
2Temperature
If the arcing zone is left open to the environment, then arc gas can dissipate, but contamination and erosion from unrestricted arc gas expansion increase
Solution Approach 1:
The patent introduces a piston as an intermediary element between the arcing zone and the external environment. The piston controls the expansion of compressed arc gas, allowing pressure management while preventing unrestricted dispersion that would cause contamination and erosion. The exhaust duct serves as a controlled pathway for arc gas release.
Solution Approach 2:
The invention creates a localized controlled environment within the piston/cylinder system where arc gas pressure can be managed differently from the external environment. The arcing zone maintains high pressure for effective arc quenching while the exhaust duct provides a controlled release path, preventing harmful unrestricted expansion.
3Force
If the spring stiffness is increased to reduce contact separation distance, then arc voltage is reduced, but the switch requires higher operating energy and the spring becomes overly rigid
Solution Approach 1:
The patent creates a dynamic restoring force system where the piston/cylinder mechanism supplements the spring force during switch-off when it is most needed. The system transitions from spring-only force during contact closure to combined spring-piston force during separation, providing optimal force control without requiring excessive spring stiffness throughout the entire operation cycle.
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 design enhances reliability and service life by minimizing contact erosion and contamination, allowing for efficient interruption of large short-circuit currents with reduced energy exchange and arc voltage, while maintaining a compact construction and avoiding undesirably high spring stiffness.
Implementation Method 1
with increasing pressure of the compressed arc gas produced in the arcing zone, is configured to generate a restoring force supporting the repelling force of the pretensioned spring
Implementation Method 2
the arcing contact of the second contact member is supported axially displaceably against the repelling force of a pretensioned spring
Implementation Method 3
an arcing zone, which accommodates compressed arc gas, is produced which is delimited axially by the free ends of the two arcing contacts and radially by the insulating nozzle toward outside of the switch
Data Source
AI summary
A high-voltage switch includes a contact arrangement having two arcing contacts, one of which is supported displaceably against the action of a pretensioned spring. When the contact arrangement is closed, the free ends of the two arcing contacts are supported on one another. When the contact arrangement is opened, the two arcing contacts separate and during this process an arcing zone, accommodating compressed arc gas, is produced which is limited axially by free ends of the two arcing contacts and radially by an insulating nozzle toward the outside. To prevent the displaceably supported arcing contact from returning against the action of the pretensioned spring when a large short-circuit current is interrupted, the switch includes a piston/cylinder system functioning as a restoring device, which communicates with the arcing zone and which, with increasing pressure of the compressed arc gas produced in the arcing zone, generates a restoring force supporting the repelling force of the pretensioned spring.