Current Transformer Calibration Using High-Precision Reference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current transformer-measuring combinations in power grids face challenges in achieving high accuracy due to the use of less expensive, lower accuracy current transformers, which are often necessary for cost reasons, leading to suboptimal measurement values.
Innovation Solution
A method and combination that incorporates a second, high-precision current transformer at the same measuring point as the first, allowing for a comparison of measured values and determination of a correction parameter to enhance the accuracy of the initial current transformer's measurements, thereby requiring only a single high-accuracy transformer for improved accuracy across multiple points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If less expensive current transformers with lower accuracy are used, then cost is reduced, but measurement precision deteriorates
Solution Approach 1:
A second current transformer with higher accuracy is temporarily connected to the measuring device before actual measurements are taken. This allows for preliminary calibration and determination of a correction factor that compensates for the lower accuracy of the first current transformer, enabling cost-effective transformers to achieve measurement precision comparable to expensive high-accuracy transformers.
Solution Approach 2:
The system changes the accuracy parameter by introducing a correction factor derived from comparisons between the first current transformer (lower accuracy) and a second current transformer (higher accuracy). This correction factor adjusts the measurement parameters of the first transformer, effectively improving its measurement precision without replacing the transformer itself.
2Ease of manufacture
If multiple current transformers with varying accuracy are used at different measuring points, then cost is reduced, but measurement precision deteriorates
Solution Approach 1:
The second current transformer is temporarily brought to each measuring point where the first current transformer is installed. This preliminary action allows for on-site calibration and correction factor determination specific to each measuring point, ensuring that even distributed low-cost transformers can achieve consistent high measurement accuracy across the entire power grid.
Solution Approach 2:
The second current transformer acts as an intermediary tool used temporarily at each measuring point to calibrate and correct the measurements of the first current transformer. This intermediary enables the system to achieve high measurement precision without permanently installing expensive high-accuracy transformers at all measuring points.
3Adaptability or versatility
If each current transformer type has its own measurement input on the measuring device, then adaptability is improved, but device complexity increases
Solution Approach 1:
The measuring device is designed with a universal measurement input that can accept any type of current transformer through a standardized connection interface. This universal input eliminates the need for multiple specialized inputs for different transformer types, reducing device complexity while maintaining adaptability through the use of correction factors for different transformer characteristics.
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 approach allows for increased accuracy in current measurements within power grids using less expensive current transformers, as the correction parameter improves the initial measurements, effectively bridging the gap between cost and precision.
Implementation Method 1
The current transformer, which is external to the measuring device, converts the very large current flowing through one of the power grid conductors, which cannot be measured directly, into a smaller current that is supplied to the measuring device.
Implementation Method 2
a second current transformer can be temporarily connected, from which the current is converted into a proportional transformer output current with greater accuracy than from the first DC current transformer
Data Source
AI summary
The invention relates to a method for measuring currents at multiple measuring points of a power network using current transformer measuring combinations, and to a current transformer measuring combination for carrying out the method. First current transformers are arranged on the current conductors of the power network, converting the current into a proportional transformer output current. This output current flows through a first input of a measuring device, which determines a current measurement value from this output. To achieve higher accuracy with the first current transformer, it is proposed that each measuring device has a second input to which a second current transformer, arranged at the same measuring point and offering greater accuracy than the first current transformer, can be temporarily connected. The two current measurements thus obtained are then compared by determining a correction factor for the first current transformer and using this correction factor for each measurement with the first current transformer.