Software DC Arc Fault Detection in Solid-State Power Controllers
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Solution Overview
Problem
Conventional electrical systems fail to detect DC arc events effectively due to their infrequent nature and inherent differences between DC and AC electrical power, leading to increased risk of undetected electrical faults and potential fires.
Innovation Solution
A software module integrated with a solid-state power controller that detects DC arc events by analyzing the difference between maximum and minimum signal values of DC electrical current over a selected time period, distinguishing between parallel and series DC arc faults and initiating appropriate output actions without the need for additional hard-wired circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermal circuit breakers or solid-state power controllers are used, then they can protect against large current spikes, but they fail to detect infrequent DC arc events that do not reach the trip threshold
Solution Approach 1:
The patent replaces conventional thermal-mechanical circuit breakers and hard-wired arc-detecting circuits with a software-based detection system. The software module analyzes current signal characteristics (such as rate of change, frequency content, and waveform patterns) to identify DC arc events, eliminating the need for additional mechanical sensing components while achieving superior detection capability.
Solution Approach 2:
The existing solid-state power controller's current sensing and processing capabilities are leveraged to perform arc detection. The system uses its own internal resources (microprocessor, existing current transformers, signal processing circuitry) to detect arcs without requiring separate dedicated arc-detection hardware, making the existing system serve multiple functions.
2Reliability
If additional hard-wired arc-detecting circuits are added to thermal circuit breakers or power controllers, then DC electric arc detection capability is improved, but device size, weight, and expense increase
Solution Approach 1:
The software module is designed to perform multiple functions within the power controller, including arc detection, fault classification (series vs. parallel arcs), and coordination with protection devices. This multi-functional approach eliminates the need for separate dedicated arc-detection hardware, reducing overall system complexity while maintaining comprehensive protection capabilities.
Solution Approach 2:
The patent replaces physical hard-wired arc-detecting circuits with software-based analysis of existing current signals. By using digital signal processing techniques applied to current already being measured for power control, the system achieves arc detection without additional sensing hardware, thereby reducing device size and cost.
3Device complexity
If a one-size-fits-all approach is used to identify electrical arc events for both DC and AC power, then device simplicity is maintained, but the device lacks intelligence to distinguish between DC and AC arc characteristics and disregard transient events
Solution Approach 1:
The software module dynamically adapts its detection parameters and analysis methods based on the detected electrical power type (DC or AC). It adjusts its signal processing characteristics, threshold settings, and waveform analysis techniques according to whether the system is operating with DC or AC power, enabling accurate arc detection specific to each power type while using a single unified device.
Solution Approach 2:
The system changes its operational parameters based on the power type detected. For DC systems, it monitors for sustained current increases and specific waveform patterns characteristic of DC arcs. For AC systems, it analyzes arc detection during voltage zero-crossings and uses different threshold criteria. This parameter adaptation allows one device to accurately detect arcs in both DC and AC environments.
Data Source
AI summary
A DC arc fault device and methodology includes acquiring a signal in response to a DC current. A software module identifies a parallel DC arc event when a difference between a maximum signal value and a minimum signal value exceeds a threshold. The software module also determines average signal values over multiple selected time periods and identifies a series DC arc event in response to the difference between the average values exceeding a predetermined threshold.