Transformer Tap Changer Monitoring via Waveform Analysis
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Solution Overview
Problem
Monitoring the health of a transformer equipped with a tap changer is challenging due to the difficulty in extracting information indicative of tap changer performance from available waveforms, especially at high loads, which affects maintenance planning and reliability.
Innovation Solution
A monitoring device and method that utilize a waveform analyzer to obtain and process waveforms of power transmission properties at both transformer sides, extracting information such as operation duration time and amplitude of tap change operations to assess tap changer health without requiring dedicated sensors or additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional transformer monitoring methods are used, then general transformer health can be monitored, but tap changer performance information cannot be extracted
Solution Approach 1:
The patent extracts tap changer performance information from general transformer waveforms by identifying specific characteristics (amplitude, duration, frequency) of tap change events. The waveform analyzer isolates tap changer-related signals from the overall transformer operation data, enabling separate evaluation of tap changer health without requiring dedicated sensors.
Solution Approach 2:
The patent replaces mechanical/dedicated sensing systems with electrical waveform analysis. Instead of using separate mechanical sensors on the tap changer, the system uses electrical waveform measurements from existing transformer monitoring points to infer tap changer performance, substituting a complex mechanical measurement system with a simpler electrical analysis approach.
2Reliability
If dedicated sensors are added to monitor tap changer, then tap changer health can be monitored, but device complexity and cost increase
Solution Approach 1:
The patent makes the existing waveform analyzer perform multiple functions: it continues to monitor general transformer health while simultaneously extracting and analyzing tap changer performance information. This multi-functionality eliminates the need for separate dedicated monitoring systems, reducing overall device complexity while maintaining comprehensive monitoring capability.
Solution Approach 2:
The existing transformer monitoring system serves itself by extracting additional tap changer information from the waveforms it already captures. The waveform analyzer uses its existing computational resources and measurement channels to provide both general transformer monitoring and specific tap changer health assessment without requiring additional hardware investments.
3Measurement precision
If waveform processing is performed to extract tap change information, then tap changer health can be assessed, but processing complexity increases
Solution Approach 1:
The patent segments the waveform processing task into distinct analytical components: detecting tap change events, measuring amplitude characteristics, calculating duration, and determining frequency. This segmentation allows each parameter to be extracted using focused, simplified processing algorithms rather than attempting complex overall waveform analysis, reducing computational complexity while maintaining measurement precision.
Data Source
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AI summary
The invention is concerned with a monitoring device, method and computer program product for monitoring a transformer comprising a tap changer. The transformer has at least two magnetically coupled windings and a tap changer comprising impedance elements and a changeover switch configured to gradually pass the impedance elements when changing between two tap changer positions during a tap change operation. The method is performed in the monitoring device and comprises: obtaining (50) waveforms of measured power transmission properties recorded at the first and second transformer sides, processing (52, 54, 56) the recorded waveforms for obtaining at least one waveform (Ploss) representing a tap change operation, and extracting (56, 60) information indicative of the performance of the tap change from the at least one waveform that represents the tap change operation.