Inductive Voltage Transformer Harmonic Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inductive voltage converters used in low- and medium-voltage networks suffer from natural oscillations in the frequency range relevant to harmonics, limiting their ability to accurately measure harmonics and THD values, especially above 1.5 kHz, and existing solutions are maintenance-intensive and impractical for field use.
Innovation Solution
The design of the primary coil with a specific configuration of double layers and adjusted dielectric constants and distances between layers achieves an almost linear transmission behavior across a wide frequency range, ensuring accurate harmonic measurement with minimal error and reduced maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an inductive voltage converter is used to transmit voltage from low- and medium-voltage networks, then voltage transformation is achieved, but natural oscillations in the frequency range from 2 kHz to 15 kHz strongly influence the transformation ratio, making harmonic measurement impossible or highly inaccurate
Solution Approach 1:
The patent applies parameter changes by modifying the capacitance values in the circuit. Specifically, a first capacitor is connected in parallel to the primary coil and a second capacitor is connected in series with the primary coil, with specific capacitance relationships (C1 ≥ C2/3 and C1 ≤ 3C2) to compensate for natural oscillations and achieve constant transformation ratio across the frequency range up to 9 kHz
Solution Approach 2:
The patent introduces capacitors as intermediary elements that mediate between the primary coil and the voltage source. These capacitors act as compensating elements that counteract the natural oscillations of the inductive voltage converter, enabling accurate harmonic measurement by stabilizing the transformation ratio
2Reliability
If parallel-connected capacitors are added to the front side of the primary coil to reduce natural oscillations, then transmission behavior improves, but the solution becomes maintenance-intensive and requires laboratory conditions with high demands on dielectric strength
Solution Approach 1:
The patent specifies parameter ranges for the capacitors (C1 ≥ C2/3 and C1 ≤ 3C2) that balance performance improvement with practical operability. These parameter constraints enable the system to achieve constant transformation ratio while using capacitors with manageable dielectric strength requirements, reducing maintenance needs compared to previous solutions
3Measurement precision
If the frequency band is limited to below 1.5 kHz to maintain acceptable transformation ratio, then measurement accuracy is maintained, but harmonics above 1.5 kHz cannot be measured
Solution Approach 1:
The patent uses capacitor parameter optimization to extend the usable frequency range. By selecting capacitors with appropriate capacitance values satisfying C1 ≥ C2/3 and C1 ≤ 3C2, the system maintains constant transformation ratio behavior up to 9 kHz, enabling measurement of harmonics that were previously inaccessible due to natural oscillations
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 allows for accurate harmonic measurement and THD determination up to 2.5 kHz with less than 5% error, making it suitable for assessing voltage quality in low- and medium-voltage networks with improved reliability and reduced maintenance needs.
Implementation Method 1
inductive voltage converters are known as voltage converters. These work on the principle of the transformer
Implementation Method 2
it was also researched whether the disruptive natural oscillations of an inductive voltage converter can be reduced by parallel-connected capacitors on the front side of the primary coil
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a voltage converter (1) comprising a primary coil (10) with a lower coil half (12) and an upper coil half (13), at least one secondary coil (20), and a coil core (30), wherein the at least one secondary coil (20) is arranged around the coil core (30) and the primary coil (10) is arranged around the at least one secondary coil (20). The windings of the primary coil (10) are designed as a plurality of double layers (11), wherein the effective capacitance of the double layers (11) of the lower coil half (12) is greater than or equivalent to the effective capacitance of the double layers (11) of the upper coil half (13).