Measuring Device Correction for Accurate Grid Current Signals
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Solution Overview
Problem
Existing current measurement systems in medium- and high-voltage grids face inaccuracies in amplitude and phase position due to lower operating currents, leading to deviations in power measurements and protection functions, necessitating precise current measurements for energy calculations while facing cost pressures.
Innovation Solution
A correction unit adjusts measured values based on individual measuring unit-specific correction instructions, using error curves to compensate for systematic errors dependent on operating variables, allowing less accurate measurement units to meet accuracy standards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If less accurate measurement units are used to reduce costs, then component costs decrease, but measurement precision deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the measured value through correction factors that adjust for systematic errors. The correction unit changes the amplitude and/or phase parameters of the measured signal based on stored correction instructions, allowing less accurate measurement units to achieve required precision levels through post-processing correction.
Solution Approach 2:
The correction unit acts as an intermediary between the measurement unit and the evaluation system. It receives measured values, applies correction based on stored correction instructions, and outputs corrected measured values, thereby mediating the accuracy issue without requiring a more precise measurement unit.
2Measurement precision
If correction instructions are stored for each measuring unit to improve accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent extracts the correction data from the measurement process itself and stores it separately in memory associated with each measurement channel. This allows the correction instructions to be prepared and stored independently, simplifying the real-time correction process while maintaining individualized correction for each measurement unit.
Solution Approach 2:
Each measurement channel is equipped with its own correction capability through individually stored correction instructions. The system serves itself by automatically applying the appropriate correction factors without requiring external intervention or complex centralized correction logic, thereby managing complexity through distribution.
3Measurement precision
If additional measuring units are used to achieve precise total value formation, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The patent makes existing measurement units serve multiple functions by enabling them to provide both protection function measurements and precise measurement function data through correction. The same measurement channels that provide protection-grade measurements can also deliver precise measurement-grade total values when correction is applied, eliminating the need for separate dedicated measurement units.
Solution Approach 2:
The correction capability is merged with the existing measurement units, allowing a single measurement channel to perform both protection and precise measurement tasks. By combining the correction function with the measurement function in the same channel, the system avoids the need for additional separate measurement units while achieving precise total value formation.
Data Source
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AI summary
The invention relates, among other things, to an arrangement with a measuring device (30, 31, 32) which is suitable for measuring an output signal (I1', I2', I3', U1', U2', U3') supplied by a measuring unit (20, 21, 22, 20U, 21U, 22U) which describes an operating parameter of a technical system (10) and for generating a measured value (Iml, Im2, Im3, ϕim1, ϕim2, ϕim3, Um1, Um2, Um3, ϕum1, ϕum2, ϕum3,). According to the invention, the arrangement includes a correction unit (40, 41, 42) configured to correct the measured value generated by the measuring device (30, 31, 32) according to a correction instruction assigned to the measuring unit individually and to generate a corrected measured value (Ikl, Ik2, Ik3, ϕik1, ϕik2, ϕik3, Uk1, Uk2, Uk3, ϕuk1, ϕuk2, ϕuk3,), wherein the measurement unit-specific correction instruction depends on the measured value generated by the measuring device (30, 31, 32) and/or on the level of another operating parameter of the technical system (10).