Circuit Assembly for High-Voltage Cable Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cable testing and fault location methods suffer from accuracy issues due to harmonics and noise caused by control intervention in high-voltage switch arrangements, leading to inaccurate loss factor measurements.
Innovation Solution
A circuit arrangement with a voltage source having a first voltage multiplier for positive and a second for negative voltage, interconnected current sources, a protective resistor, and a digital signal processor for precise voltage regulation, allowing for generation of any voltage form across a cable as a test object, with a high-precision measuring instrument for ohmic, capacitive, and ohmic-capacitive loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If control intervention is applied in high-voltage switch arrangements to regulate test voltage, then voltage regulation capability is improved, but harmonics and noise are generated which deteriorate measurement precision
Solution Approach 1:
The patent extracts the control function from the high-voltage switch arrangement and relocates it to the voltage source. The voltage source now directly generates the regulated test voltage waveform without requiring switching intervention, thereby eliminating the harmful harmonics and noise while maintaining voltage regulation capability
Solution Approach 2:
The patent introduces voltage multipliers as intermediary components between the voltage source and the cable under test. These multipliers enable the generation of high test voltages (up to 250kV) from lower voltage sources while maintaining waveform quality and avoiding the need for high-voltage switching that would generate harmonics
2Adaptability or versatility
If voltage multipliers are used to generate high test voltages, then voltage range is extended to 250kV, but device complexity increases
Solution Approach 1:
The voltage source is designed with multi-functionality, serving both as a voltage regulator and as a high-voltage generator through integrated voltage multipliers. This eliminates the need for separate high-voltage switching arrangements and simplifies the overall system architecture while achieving the wide voltage range from 1kV to 250kV
3Reliability
If current sources are used for charging and discharging cable capacitance, then cable testing capability is improved, but power loss increases due to forward voltage requirements
Solution Approach 1:
The patent changes the operating parameters of the current sources by optimizing their forward voltage requirements and integrating them with the voltage multipliers. This allows the current sources to operate more efficiently with reduced power loss while maintaining their essential function of charging and discharging the cable capacitance during testing
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-precision loss factor measurements with accuracy up to 1 x 10^-4 over a wide voltage range (1kV to 250kV), minimizing power loss and accurately locating cable faults.
Implementation Method 1
a voltage source having a first voltage multiplier for a positive voltage and a second voltage multiplier for a negative voltage
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to circuit arrangements for cable testing, cable diagnostics, and/or cable fault location, comprising: - a voltage source having a first voltage multiplier for a positive voltage and a second voltage multiplier for a negative voltage; - interconnected current sources in conjunction with the voltage multipliers for generating a test voltage across the load impedance of the cable for charging and discharging the load capacitance of the cable; and - a control unit connected to the voltage source and the current sources, and devices with such a circuit arrangement. The circuit arrangements are characterized in particular by the fact that any voltage waveform of different amplitudes can be generated across the cable as an impedance under test.The control unit includes a digital signal processor for regulating the test voltage, measured via a voltage divider across the cable's load impedance, and for setting the target value of the voltage source. The voltage multipliers are connected either to two main converters or to one main converter and an auxiliary converter that generates a positive and a negative auxiliary voltage.