Overhead Line Sensor Capacitance Calibration
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Solution Overview
Problem
Existing sensors for measuring electrical quantities in overhead electrical networks are not reliable due to fluctuations in environmental conditions, such as temperature and humidity, which affect the value of electrical capacitance between the sensor and ground, leading to inaccurate voltage measurements.
Innovation Solution
A device with a sensor and computation unit that injects a second electric current with a different frequency to calibrate and measure the electrical capacitance, allowing for precise determination of the electrical quantity by separating the measurement from the primary current, using a generator and conductive plates to connect the sensor to the electric line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal plate sensor is used to measure electrical quantity in overhead electrical network, then the measurement can be performed, but the measurement reliability deteriorates due to environmental condition fluctuations affecting electrical capacitance
Solution Approach 1:
The patent applies parameter changes by introducing a calibration current with a different frequency to measure and compensate for variations in electrical capacitance. The computation unit calculates the actual capacitance value based on the calibration current measurements and uses this updated parameter to correct the voltage measurement, thereby maintaining measurement precision despite environmental fluctuations.
Solution Approach 2:
The patent implements feedback by measuring the electrical capacitance between the plate and ground through calibration currents, then using this measured capacitance value to correct the voltage measurement. The computation unit continuously updates the capacitance parameter based on calibration measurements and applies this feedback to improve measurement reliability.
2Measurement precision
If a calibration current with different frequency is injected to measure electrical capacitance, then the measurement precision is improved, but the device complexity increases due to additional generator and measurement components
Solution Approach 1:
The patent applies universality by designing the electrical conductor to serve multiple functions: it carries both the primary current from the electric line and the calibration current from the generator. This multi-functionality reduces the need for separate dedicated calibration conductors, thereby limiting the increase in device complexity while still enabling precise capacitance measurement.
Solution Approach 2:
The patent merges the calibration measurement function with the existing sensor structure by injecting the calibration current through the same electrical conductor that connects the plate to the electric line. The computation unit combines processing of both primary and calibration currents, merging multiple measurement functions into a unified system that minimizes additional hardware complexity.
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 provides a more reliable measurement of electrical quantities by accounting for varying environmental conditions, ensuring accurate voltage determination through calibration and separate measurement of currents, enhancing the precision and reliability of electrical property assessments in overhead networks.
Implementation Method 1
a generator, electrically connected to the electrical conductor and configured to inject a second electric current through the electrical conductor
Implementation Method 2
a computation unit, configured to determine the electrical quantity from a value of the first electric current and a value of an electrical capacity between the plate and the ground
Data Source
AI summary
The invention relates to a device for measuring an electrical quantity of one phase of an AC electric current in an overhead electrical network, comprising: a sensor designed to be attached to an electric line of the network, the sensor including: an electrically conductive plate; an electrical conductor, designed to electrically connect the plate to the line, in order to circulate a first current from the line through the conductor; a processing unit, designed to determine the electrical quantity from value values of the first electric current and a value of a capacitance between the plate and ground. The device also comprises a generator, electrically connected to the conductor and designed to inject a second current through the conductor, the second current having a frequency other than the frequency of the first current, the processing unit also being designed to calculate the capacitance between the plate and ground as a function of the second current.