Ungrounded Three-Phase Sensor Assembly with Virtual Neutral Reference
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Solution Overview
Problem
Current high-voltage three-phase power line monitoring systems without a ground connection suffer from inaccuracies in voltage measurements due to the lack of a definitive reference point, and existing solutions that connect to ground face safety and reliability restrictions, necessitating a cost-effective and simple alternative for accurate monitoring.
Innovation Solution
A sensor assembly system with three sensor assemblies connected at a stable neutral common reference point not connected to ground, using voltage and current sensors, analog-to-digital converters, and transceivers to measure and transmit data wirelessly, eliminating the need for ground connections and reducing hardware costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor assemblies are connected to ground to obtain accurate voltage measurements, then voltage measurement accuracy is improved, but safety risks and circuit reliability issues increase due to ground connection restrictions
Solution Approach 1:
The patent introduces a virtual ground reference point that acts as an intermediary between the ungrounded sensor assemblies and the measurement system. This virtual reference point is created through signal processing and mathematical transformations rather than physical ground connection, allowing accurate voltage measurements without direct ground connection. The virtual reference point mediates between the need for a stable reference and the restriction against ground connections, resolving the contradiction between measurement accuracy and circuit reliability.
2Measurement precision
If sensor assemblies are connected to ground to obtain accurate voltage measurements, then voltage measurement accuracy is improved, but installation complexity and cost increase due to ground connection requirements
Solution Approach 1:
The patent extracts the ground connection requirement from the sensor assembly system by implementing ungrounded sensor assemblies that measure voltages relative to each other. The system takes out the physical ground connection element and replaces it with differential measurement techniques and mathematical reference point generation. This extraction eliminates the need for ground wire installation, grounding electrodes, and associated safety clearance requirements, significantly simplifying installation while maintaining measurement accuracy through computational methods.
3Ease of operation
If ungrounded sensor assemblies are used to avoid ground connection restrictions, then installation simplicity is improved, but voltage measurement accuracy deteriorates due to lack of definitive reference point
Solution Approach 1:
The patent implements feedback mechanisms through signal processing algorithms that continuously refine the virtual ground reference point based on measurements from all three sensor assemblies. The system uses the collective data from phase-to-phase voltage measurements to iteratively establish and maintain an accurate virtual reference point. This feedback loop compensates for the lack of physical ground connection, allowing the system to achieve voltage measurement accuracy comparable to grounded systems while maintaining installation simplicity.
Solution Approach 2:
The patent makes the sensor assemblies universal by designing them to function both in grounded and ungrounded configurations. The sensor assemblies measure phase-to-phase voltages that can be used directly for ungrounded operation or combined with ground connections for traditional operation. This multi-functionality allows the same hardware to achieve accurate measurements through different measurement strategies, resolving the contradiction between installation simplicity and measurement precision by providing flexibility in reference point establishment.
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 provides accurate voltage and current monitoring without ground connections, simplifying installation, reducing costs, and avoiding ground-related restrictions, while maintaining acceptable voltage accuracy, even when phase voltages differ.
Implementation Method 1
The current sensor is magnetically coupled to the one connected phase of the power line
Data Source
AI summary
A sensor assembly system and method for providing good voltage accuracy for monitoring a three phase high voltage power line without connecting to ground. The sensor assembly system comprises three sensor assemblies having reference point ends not connected to ground. All three sensor assemblies are connected together at the reference point ends to create a neutral common reference point not connected to ground potential that is at zero volts when all of the three phases are at the same line voltage.