Floating Reference Voltage Sensor for Ungrounded High-Voltage Measurement
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Solution Overview
Problem
High-voltage recloser systems require significant electrical insulation, leading to bulky and inflexible voltage sensor and controller configurations due to the need for long distances between the recloser controller and high-power transmission lines, making it challenging to accurately measure low energy analog voltages in high-energy transmission line electrodes.
Innovation Solution
A floating reference voltage sensor system with a capacitive voltage divider network is used, where the voltage screen is positioned closer to the high-energy transmission line than to the ground plate, allowing for compact and lightweight designs by disconnecting the voltmeter and controller from ground, enabling precise measurement of low energy voltages across the voltage screen to ground without direct earth connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the recloser controller is located at a long distance from the high-power transmission lines to provide sufficient electrical insulation, then safety and insulation requirements are met, but the device size, weight, and placement flexibility are significantly reduced
Solution Approach 1:
The voltage measurement function is segmented from the main recloser controller and performed at the high-voltage terminal using a dedicated voltage sensor. This segmentation allows the controller to be smaller and closer to the transmission line, while the sensor handles the high-voltage measurement independently with proper insulation.
Solution Approach 2:
A voltage sensor acts as an intermediary device between the high-voltage transmission line and the recloser controller. It measures the high-voltage signal and transmits it to the controller, enabling the controller to be positioned closer to the transmission line without direct exposure to high voltage, thus reducing insulation requirements and overall system size.
2Reliability
If extensive electrical insulation is implemented to safely measure high-voltage transmission lines, then measurement safety is ensured, but the system becomes bulky and less flexible in placement
Solution Approach 1:
The measurement system is divided into a high-voltage sensor portion at the transmission line terminal and a low-voltage controller portion. The sensor performs the dangerous high-voltage measurement function with adequate insulation, while the controller can be flexibly placed nearby without requiring equivalent insulation, thus improving placement adaptability.
Solution Approach 2:
The voltage sensor serves as an intermediary that isolates the controller from high-voltage dangers. It safely interfaces with the high-voltage transmission line and provides isolated measurements to the controller, enabling flexible placement options for the controller without compromising measurement safety.
3Measurement precision
If the voltage sensor is positioned close to the high-energy transmission line for accurate measurement, then measurement accuracy improves, but the required electrical insulation increases system size and complexity
Solution Approach 1:
The system segments the measurement function into a dedicated voltage sensor at the transmission line (handling high voltage with necessary insulation) and a separate controller (handling low voltage with minimal insulation). This allows accurate measurement close to the transmission line while concentrating insulation requirements in the sensor portion only.
Solution Approach 2:
The voltage sensor acts as an intermediary measurement device that can be positioned close to the high-energy transmission line for accurate measurements. It provides electrical isolation between the high-voltage source and the controller, reducing overall system complexity by localizing insulation requirements to the sensor interface.
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 configuration reduces the need for extensive electrical insulation, allowing for more flexible placement and reduced size and weight of the recloser controller, while maintaining accurate voltage measurements, thus enhancing the operational flexibility and cost-effectiveness of high-voltage transmission line monitoring systems.
Implementation Method 1
a voltage divider network for measuring low energy analog voltage and the voltage divider network and the recloser controller are disconnected from ground
Implementation Method 2
The voltage screen is made of a conductive metal. The interior of the voltage sensor may be filled with a dielectric material. Conductive leads from the voltage screen and the earth ground may be connected to a voltmeter at the recloser controller. A first capacitance may exist between the ground plate and the voltage screen, and a second capacitance may exist between the voltage screen and the power line electrode.
Implementation Method 3
The interior of the voltage sensor may be filled with a dielectric material
Data Source
AI summary
Systems and methods for measuring low energy voltage in a high energy transmission line electrode divider network. A floating reference voltage screen is positioned between a high energy transmission line electrode and a ground plate at a distance from the high energy transmission line electrode that is shorter than a distance between the ground plate and the floating reference voltage screen. A first conductive lead electrically couples the high energy analog transmission line electrode to a first input of a voltmeter that is connected to a controller. A second conductive lead electrically couples the floating reference voltage screen to a second input of the voltmeter. An alternating voltage drop is measured across the high energy transmission line electrode and the floating reference voltage screen by electronics of the voltmeter connected to the controller. The controller and the voltmeter are both disconnected from the ground plate.