Transformer Bushing Monitoring via Phase Correlation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for monitoring transformer bushings are inadequate as they often require separate connections to high voltage sources, involve complex temperature compensation, and fail to accurately detect insulation issues under harsh conditions, leading to significant transformer-related errors.
Innovation Solution
A method and system that record time series data from multiple bushing sensors connected to common phases of a high voltage source, generate correlation models to compare relative loss tangents and amplitudes, and determine differences to identify potential bushing problems without the need for temperature sensors, using regression models for easy comparison and identification of issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature compensation is implemented in bushing monitoring, then measurement precision is improved, but device complexity increases due to required temperature sensors
Solution Approach 1:
The patent extracts and removes the temperature compensation function from the monitoring system. Instead of adding temperature sensors to compensate for temperature effects, the invention uses correlation modeling between phases to inherently eliminate temperature influence, thereby achieving precise measurement without the added device complexity
Solution Approach 2:
The patent creates a correlation model that copies the relationship between phases under normal conditions. By comparing actual measurements against this copied reference relationship, the system can detect deviations without needing direct temperature compensation, thus avoiding temperature sensors while maintaining measurement precision
2Measurement precision
If separate connections to high voltage source are used for monitoring, then measurement precision is improved, but device complexity and safety risks increase
Solution Approach 1:
The patent merges the monitoring function with the existing bushing structure by utilizing the bushing tap adaptor that is already connected to the high voltage source. Instead of requiring separate instrument transformer connections, the monitoring system uses the existing connection point to obtain measurement signals, thereby reducing device complexity while maintaining measurement capability
Solution Approach 2:
The bushing tap adaptor is designed to serve multiple functions: it provides both the high voltage connection for the bushing operation and the measurement connection for monitoring. This multi-functionality eliminates the need for separate monitoring connections, reducing complexity while preserving measurement precision through correlation-based analysis
3Device complexity
If relative measurements between bushings are used, then device complexity is reduced, but measurement precision deteriorates due to inability to detect absolute changes
Solution Approach 1:
The patent implements a feedback mechanism where the correlation model continuously compares actual measurements with expected relationships. When insulation degradation occurs, the feedback loop detects the deviation from the established correlation pattern, enabling precise detection of absolute changes while maintaining simple device structure through the use of existing bushing connections
Data Source
AI summary
A system for monitoring transformer bushings sensors, wherein first and second bushing sensors are connected to a common first phase of a high voltage source, and the third and fourth bushing sensors are connected to a common second phase of the high voltage source. A first time series is generated from the first and second bushing sensors during a predetermined time interval. A second time series, is generated from the third and fourth bushing sensors during the predetermined time interval. A correlation model for the first and second time series for determining a difference between a measured signal and an estimated signal, and generating a signal indicative of a bushing problem the difference is larger than a threshold.