Capacitive Component Parameter Determination with Temperature Compensation
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Solution Overview
Problem
Existing methods for determining bushing parameters in electrical power devices are sensitive to temperature variations and system voltage fluctuations, failing to provide accurate, temperature-compensated capacitance and loss-factor values for capacitive components.
Innovation Solution
A method that involves obtaining capacitance and loss-factor values, processing them to remove common temperature influences using eigenvector matrices and statistical correlation analysis, allowing for temperature-compensated values to be calculated, and using these values for on-line measurements and fault detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the sum-current method is used to determine bushing parameters, then the method is insensitive to temperature variations, but it is sensitive to system voltage fluctuations and cannot provide individual bushing parameter values
Solution Approach 1:
The patent segments the measurement approach by obtaining individual capacitance and loss-factor values for each bushing separately, rather than using a collective sum-current method. This allows temperature compensation to be applied to each bushing's parameters individually, resolving the contradiction between temperature insensitivity and measurement precision.
Solution Approach 2:
The patent changes the measurement parameters from collective current sums to individual capacitance and loss-factor values. By measuring and compensating these specific parameters for each bushing separately, the system achieves both temperature compensation and precise individual parameter values, overcoming the limitations of the sum-current method.
2Power
If the reference bushing method is used to compare two bushings, then the method is insensitive to system voltage fluctuations, but the bushing parameters are influenced by temperature differences between the two bushings
Solution Approach 1:
The patent extracts the temperature influence as a separate factor that can be measured and compensated. By obtaining individual capacitance and loss-factor values for each bushing and applying temperature compensation based on their respective temperatures, the system eliminates temperature differences as a source of error while maintaining voltage fluctuation insensitivity.
Solution Approach 2:
The patent introduces temperature compensation as an intermediary process between the raw measurements and the final parameter values. This intermediary step corrects for temperature differences between bushings, allowing the reference bushing method to remain insensitive to voltage fluctuations while eliminating temperature sensitivity.
3Measurement precision
If absolute bushing parameters are estimated based on bushing tap current and in-service voltage, then individual capacitance and loss-factor values can be obtained, but the measurements are sensitive to temperature variations
Solution Approach 1:
The patent applies temperature compensation as a preliminary action to the measured capacitance and loss-factor values. By obtaining the temperature characteristics of each bushing and compensating for temperature effects before final parameter determination, the system achieves accurate individual parameter measurements that are insensitive to temperature variations.
Data Source
AI summary
A method of determining the capacitance and loss-factor of each of a plurality of capacitive components of an electrical power device, wherein the method includes: a) obtaining for each capacitive component a respective capacitance value and loss-factor value, and b) processing the capacitance values and the loss-factor values, wherein the processing involves removing a common influence of temperature on the capacitance values from the capacitance values and removing a common influence of temperature on the loss-factor values from the loss-factor values to obtain for each capacitive component a temperature-compensated capacitance value and a temperature-compensated loss-factor value.