Phase Angle Calibration for Leakage Current Measurement

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Solution Overview

Problem

Existing measurement technologies face challenges in accurately measuring the phase angle of resistance component leakage current due to variations caused by degradation of apparatus and environmental temperature changes, making it difficult to measure with high accuracy.

Innovation Solution

A measurement apparatus and method that includes a magnetic core, coils, current and voltage measurement circuits, a phase angle detection circuit, and a signal generator to detect and correct the phase angle by calculating a corrected phase angle based on calibration phase angles, allowing for precise calculation of the resistance component leakage current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If phase angle measurement is performed using conventional methods, then measurement can be conducted, but measurement precision deteriorates due to phase advance or delay variations caused by apparatus degradation and environmental temperature changes

Engineering Contradiction:
Improvephase angle measurement precisionVSAvoidmeasurement reliability under varying conditions
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by performing phase angle calibration before actual leakage current measurement. The calibration process establishes a reference phase angle relationship between the voltage detection circuit and current detection circuit, allowing subsequent measurements to reference this calibrated state. This preliminary calibration step compensates for phase advance or delay variations caused by apparatus degradation and environmental temperature changes, thereby maintaining measurement precision and reliability.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If manual adjustment or correction is performed during manufacturing or maintenance, then initial measurement accuracy can be achieved, but measurement precision deteriorates over time due to apparatus degradation and environmental variations

Engineering Contradiction:
Improveinitial measurement accuracyVSAvoidtime for re-adjustment and maintenance
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent implements self-service by enabling the measurement apparatus to automatically perform phase angle calibration using its own internal resources. The system uses the signal generator, voltage detection circuit, and current detection circuit to conduct self-calibration without requiring external adjustment tools or manual intervention. This self-calibration capability allows the apparatus to maintain measurement precision over time without requiring maintenance personnel for re-adjustment, effectively eliminating the loss of time associated with manual maintenance.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If complex adjustment procedures are implemented to maintain accuracy, then measurement precision can be maintained, but device complexity increases

Engineering Contradiction:
Improvephase angle measurement accuracyVSAvoidcomplexity of calibration and adjustment procedures
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies merging by integrating the calibration function directly into the existing measurement apparatus structure. The signal generator, voltage detection circuit, current detection circuit, and controller work together as a unified system where the calibration process utilizes the same hardware components already present for measurement. This integration eliminates the need for separate calibration equipment or complex external adjustment procedures, maintaining measurement precision while minimizing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables high-accuracy measurement of the phase angle and resistance component leakage current, reducing the need for manual adjustments and equipment setup, and improving measurement reliability across varying conditions.

Implementation Method 1

a magnetic core capable of being disposed so as to surround a wire; first and second coils wound around the magnetic core

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4465064A1Measurement apparatus and measurement method
Publication Date: 2024.11.20 YOKOGAWA ELECTRIC CORP
  • EP4465064A1 patent drawingFigure 1
  • EP4465064A1 patent drawingFigure 2
  • EP4465064A1 patent drawingFigure 3

AI summary

A phase angle is measured accurately when a resistance component leakage current is measured. A measurement apparatus 10 according to the present disclosure includes a magnetic core 11, first and second coils L1 and L2 wound around the magnetic core 11, a current measurement circuit 12, a voltage measurement circuit 13, a phase angle detection circuit 15, a signal generator 14 that can output sinusoidal waves to the second coil 12 and the phase angle detection circuit 15, and a controller 16. The phase angle detection circuit 15 can detect a calibration phase angle between a current measured by the current measurement circuit 12 when the signal generator 14 is outputting the sinusoidal waves, and one of the sinusoidal waves input from the signal generator 14. The controller 16 calculates a corrected phase angle based on a phase angle and the calibration phase angle, and calculates a resistance component leakage current based on a leakage current and the corrected phase angle.