Ground Fault Detection in Photovoltaic Strings Using Averaged Sensor Data
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Solution Overview
Problem
Large-scale photovoltaic power generation systems face decreased ground fault detection accuracy due to increased noise interference from longer cable lengths and diverse installation sites, making it difficult to accurately detect and address ground faults in photovoltaic power generating devices.
Innovation Solution
A ground fault detecting device comprising detectors, calculators, and judgment makers that calculate and compare mean values of detection outputs with set values to determine the presence of ground faults in both photovoltaic strings and connecting cables, reducing noise-induced false detections by averaging multiple outputs and adjusting sensitivity based on detection values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the photovoltaic power generation system is scaled up to increase power output, then the power generating capacity is improved, but the ground fault detection accuracy deteriorates due to increased noise from longer cables and diverse installation sites
Solution Approach 1:
The detection system is segmented into multiple detectors distributed across different photovoltaic strings and locations. Each detector locally monitors its segment, and the results are aggregated through calculation and logical judgment, allowing the system to maintain detection accuracy despite the large overall system size and associated noise levels
Solution Approach 2:
Multiple detection outputs from distributed detectors are merged through calculation (averaging) and logical judgment operations. This combining approach allows the system to distinguish actual ground faults from random noise by analyzing patterns across multiple detection points, thereby maintaining detection accuracy in large-scale systems
2Reliability
If multiple detectors are deployed to monitor different photovoltaic strings, then the detection coverage is improved, but the noise interference increases making false detection more likely
Solution Approach 1:
The system implements feedback through calculation and logical judgment operations that continuously analyze detection outputs from multiple detectors. By comparing and averaging multiple readings, the system provides feedback that distinguishes consistent fault signals from random noise, reducing false detections while maintaining comprehensive coverage
Solution Approach 2:
The system changes the parameter of detection sensitivity by using logical judgment and averaging operations on multiple detection outputs. This parameter transformation allows the system to maintain high detection coverage while filtering out noise, as the collective analysis of multiple detectors provides a more reliable indication of actual faults
Data Source
AI summary
A photovoltaic power generating device comprising a current collecting box side detector for detecting a ground fault in each of the photovoltaic strings, a switch disposed in correspondence to each of the photovoltaic strings and interposed between the photovoltaic string and a connecting cable, a current collecting box including a control unit providing an on/off control of the switch according to the detection result from the detector, a detector that detects a ground fault in a connecting cable between the current collecting box and the power conditioner, a switch interposed between the connecting cable and the inverter, and a power conditioner including a control unit providing an on/off control of the switch according to the detection result from the detector.