Distributed Grid Fault Detection for Split Fault Current Paths
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Solution Overview
Problem
In power systems with distributed energy sources, fault currents are split among multiple power sources, preventing protection devices from triggering due to insufficient fault current thresholds, leading to potential blind spot faults and accidents.
Innovation Solution
A method and device that detect faults by comparing input and output currents at a collection point between the AC power source and parallel circuits, determining if a fault has occurred based on greater input current, and triggering protection devices when specific thresholds are exceeded, with additional collection points to identify blind spot faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If distributed power sources are added to the power system, then power supply reliability is improved, but fault detection capability deteriorates
Solution Approach 1:
The patent introduces a fault detection device as an intermediary component that monitors current at multiple collection points. This mediator detects faults by comparing current directions and magnitudes, solving the problem where distributed power sources mask fault currents from traditional protection devices.
Solution Approach 2:
The patent transitions from single-point current monitoring to multi-dimensional monitoring by setting collection points at multiple locations (power source side, load side, and distributed power source side). This dimensional expansion enables comprehensive fault detection despite the complex current paths created by distributed power sources.
2Object-affected harmful factors
If protection devices are used to detect faults, then circuit safety is improved, but protection reliability deteriorates in distributed power systems
Solution Approach 1:
The patent segments the monitoring function by placing collection points at different locations (power source side collection point, load side collection point, and distributed power source side collection point). Each segment monitors specific current characteristics, and their combined analysis provides reliable fault detection that overcomes the limitations of single protection devices.
Solution Approach 2:
The patent implements feedback by continuously monitoring current at multiple collection points and using the collected data to determine fault conditions. The fault detection device receives real-time current information, processes it according to predefined criteria, and triggers protection actions when faults are detected, creating a closed-loop protection system.
Data Source
AI summary
Provided are a grid fault detection method and a device. The grid includes at least one AC power source provided by a public grid. The AC power source is coupled to a plurality of parallel circuits, each including a plurality of parallel branches. The parallel branches are each connected with a load and/or a DC power source. The grid fault detection method having the distributed energy resource includes: selecting a first collection point between the AC power source and the plurality of parallel circuits, and collecting a current value and a current direction of the first collection point; comparing an output current and an input current of the first collection point, and upon the input current being greater than the output current, it is determined that the plurality of parallel circuits are faulty. Accordingly, the plurality of collection points check the fault, so as to trigger a protection device.