Switchgear Voltage Sensor Drift Compensation via Gain Adjustment
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Solution Overview
Problem
Voltage sensors using epoxy dielectric capacitors experience drift due to changes in permittivity over time, leading to measurement inaccuracies beyond a predetermined accuracy threshold.
Innovation Solution
A capacitive voltage sensor compensation system that compensates for drift in switch gear voltage sensors by using a microcontroller to determine capacitance changes and adjust gain values through a programmable gain amplifier to maintain accurate voltage measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a voltage sensor uses a capacitor with epoxy dielectric material, then the sensor can operate at high voltages, but the permittivity of the epoxy changes over time causing voltage drift and measurement inaccuracies
Solution Approach 1:
The system continuously monitors the capacitance of the epoxy dielectric capacitor and uses feedback control to adjust the gain of the measurement circuit. A microcontroller measures the actual capacitance value, compares it to the expected value, and dynamically compensates for drift by adjusting the gain parameter, thereby maintaining measurement accuracy despite permittivity changes over time
Solution Approach 2:
The system changes the electrical parameter (gain) of the measurement circuit in response to detected capacitance drift. By dynamically adjusting the gain parameter based on measured capacitance changes, the system compensates for the permittivity variations of the epoxy material, maintaining accurate voltage measurements throughout the sensor's operational life
2Duration of action of stationary object
If the permittivity of the epoxy dielectric material changes over time, then the capacitance of the capacitor drifts, but this causes measurement inaccuracies beyond a predetermined accuracy threshold
Solution Approach 1:
The system performs preliminary characterization of the epoxy dielectric's capacitance behavior during manufacturing or initial operation. This preliminary data is used to establish baseline parameters and compensation algorithms that are built into the microcontroller, enabling proactive correction of drift before it significantly impacts measurement accuracy
Solution Approach 2:
The system implements continuous feedback monitoring of the capacitor's actual capacitance value and dynamically adjusts measurement parameters to compensate for drift. The microcontroller periodically measures capacitance, detects deviations from expected values, and applies real-time corrections to maintain accuracy over extended operational periods
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 system effectively compensates for capacitance drift, ensuring high-accuracy voltage measurements by adjusting gain values to counteract changes in permittivity, thereby reducing measurement errors.
Implementation Method 1
Due to change in the permittivity of epoxy over time, a voltage sensor that uses a capacitor with an epoxy dielectric may be subject to voltage drift
Data Source
Figure 1A
Figure 1B
Figure 2~3
AI summary
A system and method for compensating for drift in a switch gear voltage sensor. The system includes a circuit, and an electronic processor. The circuit is configured to receive a first signal from a first capacitor of the voltage sensor and receive a second signal from a second capacitor of the voltage sensor. The circuit is further configured to generate a third signal and a fourth signal based on the first signal and the second signal. The electronic processor is configured to receive the third signal and the fourth signal and determine an angular frequency, a phase difference, a resistance value, a voltage across a compensation capacitor, an initial gain, a capacitance of the second capacitor, a capacitance and a voltage of the compensation capacitor, and a final gain.