Transformer Accuracy Testing via Equivalent Circuit Analysis
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Solution Overview
Problem
Current methods for testing the accuracy of voltage transformers are costly and time-consuming, requiring dismantling and shipping to high-voltage laboratories, and do not account for the non-linear, frequency-dependent behavior of voltage converters, making it difficult to check accuracy without using nominal voltage.
Innovation Solution
A method and device that use an equivalent circuit diagram to automatically determine the accuracy of transformers by evaluating a test response to a test signal, allowing for on-site testing at low voltages, and includes a portable test device capable of measuring and calculating transformer behavior at different frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage transformers are tested in high-voltage laboratories using nominal voltage, then measurement precision is improved, but loss of time and productivity deteriorate due to dismantling, shipping, and complex assembly work
Solution Approach 1:
The patent introduces an intermediary measurement approach by using a test signal and evaluating the transformer's response characteristics (magnitude and phase) to determine accuracy. This mediator method allows testing without applying nominal voltage, eliminating the need for dismantling and shipping while maintaining measurement capability through signal response analysis.
Solution Approach 2:
The patent replaces the mechanical/physical system of high-voltage nominal voltage testing with an electrical signal-based measurement system. Instead of using the transformer's rated voltage and physical operation conditions, the invention uses test signals and evaluates electrical response characteristics (magnitude and phase) to determine accuracy, thereby eliminating complex mechanical assembly and shipping requirements.
2Measurement precision
If voltage transformers are tested at nominal voltage, then measurement precision is improved, but loss of time deteriorates due to high costs and complex assembly and shipping procedures
Solution Approach 1:
The patent introduces an intermediary measurement approach by using a test signal and evaluating the transformer's response characteristics (magnitude and phase) to determine accuracy. This mediator method allows testing without applying nominal voltage, eliminating the need for dismantling and shipping while maintaining measurement capability through signal response analysis.
Solution Approach 2:
The patent creates a simplified measurement model that copies the essential testing function without requiring the full nominal voltage condition. By evaluating the transformer's response to a test signal and analyzing magnitude and phase characteristics, the invention replicates the accuracy assessment capability without the time-consuming high-voltage testing process.
3Ease of operation
If known testing methods from current transformers are applied to voltage transformers, then ease of operation is improved, but measurement precision deteriorates due to parasitic influences and non-linear frequency-dependent behavior
Solution Approach 1:
The patent applies local quality by specifically addressing the non-linear frequency-dependent behavior of voltage transformers through separate evaluation of magnitude and phase responses. Instead of using a generic testing method that treats all transformers uniformly, the invention tailors the measurement approach to account for the specific characteristics of voltage converters, including their non-linear frequency-dependent loss propagation.
Solution Approach 2:
The patent changes the measurement parameters by evaluating both magnitude and phase of the transformer's response to a test signal, rather than relying on single-parameter methods. This dual-parameter approach allows the system to account for non-linear frequency-dependent behavior and parasitic influences, maintaining measurement precision while keeping the operation simple through automated evaluation.
Data Source
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AI summary
To test a transformer (20), the transformer (20) is modeled by an equivalent circuit diagram (30) and by evaluating a test response of the transformer (20), an accuracy of the transformer (20) related to the equivalent circuit diagram (30) is automatically determined, which is then automatically converted into an accuracy of the transformer (20) related to an operating case.