Grid Relay Fault Detection via Capacitive AC Coupling
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Solution Overview
Problem
Existing onsite power systems face challenges in detecting faults in grid relays, which can lead to unsafe conditions and failures in connecting or disconnecting from the utility grid.
Innovation Solution
The implementation of a grid relay fault detection system that uses capacitively coupled AC signals to determine the state of grid relays, allowing for the identification of faults such as welded or stuck relays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fault detection methods are used, then the system structure remains simple, but the ability to detect grid relay faults is insufficient
Solution Approach 1:
The patent introduces an intermediary detection circuit that uses capacitive coupling to indirectly sense the state of grid relays. This intermediary system allows fault detection without directly interfacing with high-voltage relay contacts, thereby improving reliability while maintaining relatively simple system architecture.
Solution Approach 2:
The patent replaces direct mechanical or electrical contact-based detection methods with a capacitive sensing approach. By using the capacitive effect to detect relay state changes, the system achieves better fault detection capability without the complexity and safety risks associated with direct electrical contact methods.
2Object-affected harmful factors
If no fault detection system is implemented, then the system complexity remains low, but unsafe conditions cannot be detected
Solution Approach 1:
The detection system utilizes the existing capacitive characteristics of the power system components themselves to perform fault detection. By leveraging the natural capacitive coupling between circuit elements, the system can detect unsafe conditions without requiring additional complex sensing hardware or external intervention.
Solution Approach 2:
The patent employs an intermediary capacitive sensing mechanism that can detect harmful conditions (such as welded relay contacts) through electrical field changes without requiring direct contact with dangerous high-voltage components, thus enabling unsafe condition detection while managing system complexity.
3Measurement precision
If direct relay state monitoring is implemented, then detection accuracy improves, but safety risks increase
Solution Approach 1:
The patent introduces a capacitive coupling intermediary that allows accurate detection of relay state changes through electrical field sensing rather than direct electrical contact. This intermediary approach maintains high measurement precision for relay state detection while eliminating the safety risks associated with direct monitoring of high-voltage relay contacts.
Solution Approach 2:
The patent replaces direct electrical contact-based monitoring with capacitive sensing technology. This substitution enables accurate detection of relay state changes through changes in capacitive coupling, achieving high measurement precision without exposing the detection system to the safety risks of direct high-voltage contact.
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 solution enables effective detection of grid relay faults, ensuring safe operation of onsite power systems by allowing for timely remedial actions, such as disconnection from the grid.
Implementation Method 1
an AC signal source is capacitively coupled across contacts of a grid relay
Data Source
AI summary
A grid relay state detector includes an AC (Alternating Current) signal source capacitively coupled to at least one grid relay. It further includes a current sensor that detects an amount of AC current flowing through the at least one grid relay. A state of the at least one grid relay is determined based at least in part on the detected amount of AC current.