Ungrounded Power Line Sensor Voltage Measurement Correction
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Solution Overview
Problem
Ungrounded power line sensors experience measurement errors due to snow and ice accumulation, as these weather conditions affect the capacitive coupling between the sensor and ground, leading to inaccurate voltage readings, and existing solutions are either ineffective or costly and labor-intensive.
Innovation Solution
An alternate voltage sensing method using the power supply voltage of a data collector to identify and mitigate voltage degradation, where the collector supply voltage is calibrated to provide an alternate measurement for each phase, allowing for detection and correction of voltage deviations caused by snow and ice, thereby maintaining accurate sensing performance under adverse weather conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ungrounded power line sensors use capacitive coupling to measure voltage, then the sensor structure is simple and installation is easy, but snow and ice accumulation changes the capacitive coupling and causes measurement errors
Solution Approach 1:
The patent introduces an intermediary measurement approach by using the collector supply voltage as a reference to calculate an alternate voltage measurement. This alternate measurement serves as a mediator to detect and correct errors in the primary capacitive coupling measurements, thereby maintaining accuracy without changing the simple sensor structure
Solution Approach 2:
The system implements feedback by continuously comparing the primary voltage measurement with the alternate voltage measurement derived from collector supply voltage. When deviations are detected, the system uses the alternate measurement to correct the primary measurement, creating a closed-loop error correction mechanism
2Measurement precision
If instrumentation transformers are used to be completely resistant to snow and ice effects, then measurement accuracy is maintained, but the system becomes expensive and labor intensive to install
Solution Approach 1:
The patent creates a virtual copy of the voltage measurement function by calculating an alternate voltage measurement from the collector supply voltage. This calculated copy serves as a backup measurement that can correct errors in the primary measurement, eliminating the need for physical instrumentation transformers
Solution Approach 2:
The patent replaces the mechanical/electrical instrumentation transformer system with an electronic calculation-based solution. By using software algorithms to compute alternate voltage measurements from existing electrical signals, the system eliminates complex hardware while maintaining measurement accuracy
3Object-affected harmful factors
If the entire sensor body is turned into a large voltage sensing plate to reduce snow sensitivity, then some snow resistance is achieved, but significant snow build-up still changes the effective surface area and causes spurious voltage increases
Solution Approach 1:
The system uses feedback by continuously monitoring the relationship between collector supply voltage and phase voltage. When snow accumulation causes measurement deviations, the feedback mechanism detects these errors and applies corrections using the alternate voltage calculation, maintaining accuracy despite environmental changes
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 solution effectively tolerates snow and ice accumulation with minimal performance degradation, providing reliable voltage measurements by using the collector supply voltage to correct sensor readings and log deviations, ensuring continuous accurate monitoring of power line conditions.
Implementation Method 1
Ungrounded power line sensors measure the voltage of a medium-voltage power line relative to ground through, for example, a capacitive coupling between metal plates on the outside of the sensor and ground
Implementation Method 2
A 'Potential Transformer' (PT) is used to transform the line voltage down to a lower voltage that is more easily measured
Data Source
AI summary
A voltage sensing system and method for use with ungrounded power line sensors deployed on each phase of a power line. The voltage of each phase is measured using the sensors. This measurement is used unless there is a snow event. A collector is powered by a transformer connected to the power line being monitored and a voltage measurement circuit is configured to measure the collector supply voltage which is then used to obtain an alternate voltage measurement for each phase. When the sensor measured voltage for any phase deviates from the alternate voltage measurement by a pre-established value, a snow event has occurred and the alternate voltage measurement may then be used.