Circuit Breaker Oscillation Branch for Delayed Zero-Crossing Faults
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional AC circuit breakers struggle to promptly interrupt fault currents with delayed zero-crossing phenomena, leading to potential damage to power systems and equipment, as they require high arc voltage and longer interruption times, and are not environmentally friendly.
Innovation Solution
A method for interrupting a circuit breaker is introduced, which includes a transfer branch with an oscillation circuit formed by a transfer capacitor and inductor, and a conduction circuit. When a fault current decreases, the conduction circuit is controlled to conduct, forming a loop with the oscillation circuit and current-carrying branch, generating a transfer current that reversely superimposes with the fault current to create multiple current zeros.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional AC circuit breakers utilize current zeros for interruption, then the interruption process is simple, but fault currents with delayed zero-crossing phenomena cannot be promptly interrupted
Solution Approach 1:
The oscillation circuit is pre-configured with capacitors and inductors to generate transfer currents with predetermined characteristics. When a delayed zero-crossing fault is detected, the circuit breaker immediately activates the oscillation circuit to create artificial current zeros, eliminating the need to wait for natural current zeros and achieving prompt interruption.
Solution Approach 2:
The oscillation circuit acts as an intermediary mechanism between the power system and the fault current. By introducing transfer currents through the oscillation circuit, the system creates artificial current zeros that mediate the interruption process, allowing the circuit breaker to interrupt delayed zero-crossing fault currents without waiting for natural current zeros.
2Reliability
If SF6 circuit breakers generate very high arc voltage to force current zero, then interruption of delayed zero-crossing fault currents is achieved, but the interruption time exceeds two current cycles and environmental damage occurs
Solution Approach 1:
The patent replaces the mechanical arc voltage generation method with an electrical oscillation-based approach. Instead of relying on mechanical contact opening and high arc voltage, the oscillation circuit generates transfer currents through electromagnetic oscillation, creating artificial current zeros without the need for SF6 gas or high arc voltage, thus eliminating environmental damage.
Solution Approach 2:
The oscillation circuit changes the current parameters by introducing transfer currents with specific frequency and amplitude characteristics. By adjusting the oscillation parameters (capacitor values, inductor values), the system creates multiple current zeros with optimized timing, achieving reliable interruption of delayed zero-crossing fault currents without environmental harm.
3Reliability
If SF6 circuit breakers use high arc voltage to interrupt fault currents, then interruption is achieved, but the arc voltage requirement is extremely high and interruption time is prolonged
Solution Approach 1:
The oscillation circuit generates periodic transfer currents through electromagnetic oscillation, creating multiple current zeros within a short time frame. This periodic action allows the circuit breaker to achieve interruption success without requiring extremely high arc voltage, as the oscillating transfer currents naturally create zero-crossing points that facilitate safe interruption.
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 method enables the generation of multiple current zeros in a short period, providing multiple opportunities for zero-crossing interruption, thereby improving the reliability of circuit breaker interruptions and addressing the challenges of delayed zero-crossing phenomena.
Implementation Method 1
forming a transfer current continuously oscillating through oscillating discharge of the oscillation circuit
Implementation Method 2
an oscillation circuit formed by a transfer capacitor and an inductor
Implementation Method 3
reversely superimposing the transfer current with the fault current in the current-carrying branch during a continuous oscillation process to enable the current-carrying branch to generate a plurality of current zeros
Data Source
AI summary
The present disclosure discloses a method for interrupting a circuit breaker, wherein the circuit breaker comprises a transfer branch and a current-carrying branch which are connected in parallel, the transfer branch comprising an oscillation circuit formed by a transfer capacitor and an inductor and a conduction circuit connected in series with the oscillation circuit, and the method comprises the following steps: S100: when a fault current in the current-carrying branch decreases, controlling the conduction circuit in the transfer branch to conduct, and forming a loop by the conduction circuit after conduction with the oscillation circuit and the current-carrying branch; S200: forming a transfer current continuously oscillating through oscillating discharge of the oscillation circuit, and injecting the transfer current into the current-carrying branch through the loop.