Integrated High-Voltage Divider for Harmonics Measurement
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Solution Overview
Problem
Conventional capacitor voltage transformers (CVTs) in high-voltage networks lack sufficient accuracy for measuring voltage harmonics due to their narrow frequency band resonance, necessitating the use of additional equipment like precision HV resistor capacitor dividers (RCDs) for accurate harmonics measurement, which increases space and cost requirements in electrical substations.
Innovation Solution
A high-voltage divider combining a capacitor stack and a resistor stack within insulating means, allowing for high accuracy harmonics measurement while providing functionalities similar to CVTs, reducing the need for separate CVT and RCD transformers and optimizing space and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional capacitor voltage transformers (CVTs) are used for voltage measurement in high-voltage networks, then the device provides voltage stepping down functionality, but the measurement accuracy for voltage harmonics is insufficient due to narrow frequency band resonance
Solution Approach 1:
The patent combines a capacitor voltage divider (CVT) and a resistor capacitor divider (RCD) into a single integrated high-voltage divider device. The capacitor stack provides voltage stepping down for nominal frequency measurements, while the resistor stack in parallel provides broad frequency response for harmonics measurement. This merging eliminates the need for separate CVT and RCD equipment, resolving the contradiction by achieving both narrow-band precision and broad-band adaptability in one device.
Solution Approach 2:
The integrated high-voltage divider performs multiple functions simultaneously: it acts as a CVT for nominal frequency voltage measurement and as an RCD for harmonics measurement across a broad frequency spectrum. The dual-stack architecture enables the single device to serve both specialized measurement needs, achieving universality that resolves the frequency band width limitation while maintaining measurement precision.
2Measurement precision
If separate CVT and RCD transformers are installed for accurate harmonics measurement, then measurement accuracy is improved, but space requirements and installation costs increase
Solution Approach 1:
The patent merges the functionality of separate CVT and RCD transformers into a single integrated high-voltage divider with shared insulating means and common structural support. This consolidation reduces the total equipment footprint in the substation while maintaining the measurement precision of both divider types through their respective capacitor and resistor stacks operating in parallel.
3Measurement precision
If separate CVT and RCD transformers are installed for accurate harmonics measurement, then measurement accuracy is improved, but installation costs increase
Solution Approach 1:
The integrated design combines capacitor stack, resistor stack, and shared insulating means into a single manufacturable unit. This merger reduces installation costs by eliminating duplicate mounting structures, connection hardware, and commissioning procedures while maintaining the measurement precision benefits of both CVT and RCD configurations through their parallel operation within the unified device.
4Reliability
If conventional CVT with oil and polypropylene insulation is used, then the device provides adequate electrical insulation, but the equipment size and weight increase
Solution Approach 1:
The patent employs composite insulation materials including oil, polypropylene, and paper in combination within the insulating means. This composite approach provides adequate electrical insulation performance for high-voltage operation while optimizing the density and structural efficiency of the insulation system, thereby reducing the overall weight compared to conventional single-material insulation designs.
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
Enables high accuracy harmonics measurement and reduces equipment size and installation costs by integrating functionalities of CVTs and RCDs into a single transformer, addressing space constraints and improving power quality monitoring in high-voltage systems.
Implementation Method 1
a capacitor stack comprising two capacitors, a HV capacitors C1H and middle-voltage capacitor CM across which the transmission line signal is split
Implementation Method 2
an inductive element REACT acting as compensating reactor aimed at tuning the device to the line frequency
Implementation Method 3
an electromagnetic unit UEM contained inside a base-box BBCVT... the inductive intermediate voltage transformer TIMV to further step down the voltage
Data Source
AI summary
An HV divider stepping down an input high voltage in HV systems includes a primary part with first and second assemblies within an insulator and a divider input terminal. The first assembly is a first capacitor stack having first high and middle voltage capacitors. The second assembly has a second capacitor stack and resistor stack in parallel. The second capacitor stack has second high and low voltage capacitors. The resistor stack has high and low voltage resistors. The secondary part has an electromagnetic unit and a secondary part output set has: a first output terminal subset, deriving from a first intermediate terminal processed through electromagnetic unit, to provide a first output voltage subset for measuring amplitude of the input voltage at nominal frequency range; a second output terminal, deriving from a second intermediate terminal, to provide a second output voltage for measuring waveform of the input high voltage.