Solid-State Circuit Breaker Current Limiting for Fault Isolation
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Solution Overview
Problem
Solid-state circuit breakers face limitations in fault discrimination and protection due to thermal and overcurrent limits, leading to harmonic distortion and thermal stress, particularly when using repetitive switching to reduce fault currents.
Innovation Solution
A power system with a solid-state circuit breaker that includes a galvanic isolation switching device, a solid-state switching device in anti-parallel configuration, an energy dissipation branch, and an assistive branch with a resistor and inductor, controlled to operate in continuous or intermittent current limiting modes to reduce current magnitude and dissipate energy, thereby mitigating harmonic distortion and thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If repetitive switching is used to reduce fault current magnitude, then the current magnitude is reduced, but harmonic distortion increases and thermal stress is generated
Solution Approach 1:
The invention divides the single solid-state switching operation into multiple segmented switching intervals. The controller divides the fault condition response into discrete time intervals, applying switching actions in segments rather than continuously, which reduces the total fault current magnitude while controlling harmonic distortion through structured interruption patterns.
Solution Approach 2:
The invention implements periodic switching actions during fault conditions. The controller applies repetitive but controlled switching at specific intervals, creating periodic current interruption patterns that limit fault current magnitude while managing harmonic distortion through the periodic nature of the switching cycles.
2Speed
If solid-state circuit breakers operate at high speed for fault isolation, then fault isolation speed is improved, but thermal stress on semiconductors increases due to overcurrent limits
Solution Approach 1:
The invention applies preliminary current limiting actions before the solid-state circuit breaker reaches its thermal limits. The controller detects fault conditions and initiates switching actions that pre-limit the current magnitude, preventing excessive thermal stress accumulation while maintaining fast fault isolation capability within semiconductor thermal constraints.
Solution Approach 2:
The invention maintains continuous protective action through coordinated operation of the solid-state circuit breaker with upstream protective devices. The solid-state breaker provides continuous monitoring and initiates continuous protective switching actions, ensuring uninterrupted protection while managing thermal stress through sustained controlled operation rather than single high-stress events.
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 system effectively reduces fault current magnitude, minimizes harmonic distortion, and reduces thermal stress on solid-state circuit breakers, allowing for efficient fault detection and isolation while maintaining power system stability.
Implementation Method 1
an inductor, and a switching device coupled together in series
Implementation Method 2
an energy dissipation branch coupled in parallel with the solid-state switching device, the energy dissipation branch including an energy dissipation device
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
Systems, methods, techniques and apparatuses of high current protection are disclosed. One exemplary embodiment is a power system comprising a solid-state circuit breaker (110) including a solid-state switching device (113), an energy dissipation branch (114), an assistive branch (116), and a controller (120). The energy dissipation branch is coupled in parallel with the solid-state switching device and includes an energy dissipation device (115). The assistive branch is coupled in parallel with the solid-state switching device and includes a resistor (119), an inductor (118), and a galvanic isolation switching device (117) coupled together in series. The controller is configured to determine the solid-state circuit breaker is conducting a high magnitude current, select a continuous current limiting mode or an intermittent current limiting mode, and operate the solid-state switching device based on the selected current limiting mode. Fig. 1