Synchronized Vacuum Switchgear for Transient Management
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Solution Overview
Problem
Vacuum circuit breakers face challenges in synchronizing operations with high-frequency currents, leading to potential re-ignitions and transient over-voltages during power distribution, which can damage equipment and are difficult to manage with existing synchronization techniques.
Innovation Solution
An electric power distribution switchgear system that includes a synchronized vacuum circuit breaker and a surge arrester arrangement, where the circuit breaker opens at a phase angle synchronized with the current to minimize re-ignitions, and the surge arrester handles lower-frequency transients caused by current chopping, allowing for remote placement and effective management of transient over-voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum circuit breaker uses synchronized opening technique, then re-ignition during breaking is avoided, but transient over-voltages caused by current chopping still occur
Solution Approach 1:
The patent segments the transient over-voltage problem into two distinct types: high-frequency transients from re-ignition (solved by synchronization) and lower-frequency transients from current chopping (handled by surge arrester). This segmentation allows targeted protection strategies for each transient type.
Solution Approach 2:
The surge arrester arrangement acts as an intermediary device between the vacuum circuit breaker and the protected equipment. It specifically handles the lower-frequency transient over-voltages that the synchronized breaking cannot eliminate, providing complementary protection.
2Ease of operation
If surge arrester is placed remotely from protected equipment, then installation flexibility is improved, but protection effectiveness may be reduced
Solution Approach 1:
The patent changes the frequency parameter consideration by designing the surge arrester to specifically handle lower-frequency transients. This parameter differentiation allows the surge arrester to be placed remotely while maintaining effectiveness for its targeted frequency range.
Solution Approach 2:
The surge arrester serves as an intermediary protection device that can be positioned at an optimal location rather than directly at the equipment, providing flexible installation while maintaining protection capability for lower-frequency transients.
3Speed
If vacuum circuit breaker operates at high frequency, then switching speed is improved, but multiple re-ignitions may occur during interruption
Solution Approach 1:
The synchronization technique performs a preliminary action by pre-determining the optimal opening phase angle based on current waveform analysis. This preliminary synchronization prevents re-ignition before it can occur, allowing high-speed operation with stable interruption.
Solution Approach 2:
The synchronization system uses feedback from voltage and current measurements to determine the precise opening moment. This feedback mechanism ensures that the breaker opens at the optimal phase angle, preventing re-ignition even during high-frequency operation.
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 effectively reduces the risk of re-ignitions and transient over-voltages, enabling the placement of surge arresters remotely from the protected equipment while maintaining effective voltage management, thus enhancing the reliability and safety of power distribution systems.
Implementation Method 1
a synchronized vacuum switching apparatus configured to break the current to said electric power equipment using a technique synchronized with the current through the apparatus so as to avoid re-ignition during the breaking
Implementation Method 2
Vacuum circuit breakers are capable of interrupting high frequency currents... When a current is interrupted, an arc is generated. This arc must be contained, cooled and extinguished in a controlled way
Implementation Method 3
a surge arrester arrangement connected to said electric power equipment, the surge arrester arrangement being designed and configured to only handle transients caused by current chopping of the load current at the breaking
Data Source
AI summary
An electric power distribution switchgear is connected between an electric power grid and an electric power equipment. The switchgear includes a synchronized vacuum switching apparatus configured to break the current to the electric power equipment using a synchronized technique to avoid re-ignition during the breaking and thus any transients caused by such re-ignition; and a surge arrester arrangement connected to the electric power equipment, the surge arrester arrangement being designed and configured to only handle transients caused by the current chopping at the breaking. The surge arrester arrangement can be arranged remote from the electric power equipment, such as e.g. in the same casing as the synchronized vacuum switching apparatus.