Modular Power Meter Transducers with Self-Calibration
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Solution Overview
Problem
Existing power meters face challenges in flexible construction, simplified installation, and improved serviceability, particularly in field repairs and modifications, due to the need for recalibration and error compensation in current and voltage transducers, which can lead to inaccurate readings or the necessity of replacing entire modules.
Innovation Solution
A digital power meter design featuring modular current and voltage modules with detachable transducers and a data processing unit that can read and store characterization data for error correction, allowing for customization and self-discovery of phase shifts, enabling easy replacement and recalibration of transducers without requiring extensive recalibration equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If transducers are made detachable and modular for easier replacement, then ease of repair and serviceability improve, but measurement precision deteriorates due to calibration errors and the need for recalibration
Solution Approach 1:
The system performs preliminary self-calibration automatically when transducers are connected. The microprocessor executes calibration routines that measure actual transducer outputs against known reference values and store correction factors in memory, eliminating the need for manual recalibration equipment and procedures while maintaining measurement accuracy
Solution Approach 2:
The power meter performs self-calibration using its own internal resources. The microprocessor controls the calibration process, reads transducer outputs, calculates correction factors, and stores them in memory without requiring external calibration equipment or manual intervention, enabling the system to service itself when transducers are replaced
2Measurement precision
If manual calibration procedures are used for replaced transducers, then measurement precision can be maintained, but loss of time increases due to requiring calibration equipment and procedures
Solution Approach 1:
The power meter performs self-calibration using its own internal resources. The microprocessor controls the calibration process, reads transducer outputs, calculates correction factors, and stores them in memory without requiring external calibration equipment or manual intervention, enabling the system to service itself when transducers are replaced
Solution Approach 2:
The manual mechanical calibration process is replaced with an automated electronic system. The microprocessor electronically controls the calibration sequence, automatically reads transducer signals, computes correction algorithms, and programmatically stores calibration data, replacing what would otherwise require physical calibration equipment and manual procedures
3Measurement precision
If entire modules are replaced instead of individual transducers, then measurement precision is maintained, but loss of substance increases due to replacing more components than necessary
Solution Approach 1:
The system is divided into independent modular transducers that can be individually replaced. Each transducer is a separate replaceable component with its own connection interface, allowing only the specific faulty transducer to be removed and replaced while leaving other functional transducers in place, rather than replacing entire assemblies
4Ease of operation
If detachable transducers are used for flexible installation, then ease of operation improves, but reliability deteriorates due to potential connection errors and phase shift issues
Solution Approach 1:
The system uses feedback to verify correct transducer installation and connection. The microprocessor monitors transducer output signals and compares them against expected ranges and phase relationships. If connection errors or phase shifts are detected, the system can alert the installer or automatically adjust calibration parameters to compensate
Solution Approach 2:
The system performs preliminary self-calibration automatically when transducers are connected. The microprocessor executes calibration routines that measure actual transducer outputs against known reference values and store correction factors in memory, eliminating the need for manual recalibration equipment and procedures while maintaining measurement accuracy
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
The modular design enhances flexibility and serviceability by allowing for easy customization and replacement of transducers, reducing the need for recalibration and improving the accuracy of power measurements during installation and maintenance.
Implementation Method 1
A current transformer typically comprises multiple turns of wire wrapped around the cross-section of a toroidal core. The power cable conducting the load current is passed through the aperture in the center of the toroidal core and constitutes the primary winding of the transformer and the wire wrapped around the cross-section of the core comprises the secondary winding of the transformer. Current flowing in the primary winding (primary current) induces a secondary voltage and current in the secondary winding which is quantitatively related to the current in the primary winding.
Implementation Method 2
The voltage transducers of digital power meters commonly comprise a voltage divider network that is connected to a conductor in which the voltage will be measured.
Data Source
AI summary
A meter for measuring electric power consumed by a plurality of branch circuits includes interchangeable current transformers including respective transformer memories for storage of transformer characterization data and enables self-discovery of a phase shift induced by respective current transformers and the phase of current conducted by each branch circuit.