Insulation Fault Location in Multi-Module Conversion Systems
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Solution Overview
Problem
Current medium-high voltage and high-frequency isolation converter systems face challenges in accurately locating insulation abnormalities, leading to high labor and equipment costs for maintenance due to the need for extensive disassembly and the use of expensive high-voltage detection devices.
Innovation Solution
A method and device for detecting and locating insulation state in a conversion system, which involves changing the state of switches to alter the voltage between windings of transformers in conversion units, detecting current changes before and after the switch state change, and comparing these values to determine which conversion units have insulation abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If modules in the system are checked respectively to locate insulation abnormality, then accurate fault location is achieved, but large labor cost and time consumption are required for disassembly and maintenance
Solution Approach 1:
The system divides the multi-module converter into segmented detection units, where each module's insulation state can be independently detected. By applying voltage to specific winding pairs in each module and measuring leakage current through connection elements, the system can identify which specific module has insulation abnormality without checking all modules sequentially, thus reducing maintenance time while maintaining location accuracy.
Solution Approach 2:
The patent implements preliminary insulation detection by continuously monitoring leakage current through connection elements before actual insulation failure occurs. The detection system is pre-configured with voltage sources and current measurement circuits that can immediately identify insulation abnormalities when they occur, eliminating the need for time-consuming manual disassembly and inspection during maintenance.
2Measurement precision
If modules in the system are checked respectively to locate insulation abnormality, then accurate fault location is achieved, but expensive high-voltage detection devices are required for aided detection
Solution Approach 1:
The converter system's own operating voltages and currents are utilized for insulation detection. The detection system leverages the existing high-voltage DC links and switching operations within the converter modules to create test conditions, eliminating the need for external high-voltage detection equipment. The leakage current measurement circuits use standard low-voltage measurement devices to detect insulation status.
Solution Approach 2:
The detection system serves multiple functions: it monitors insulation status during normal operation, performs fault diagnosis, and provides preventive maintenance capabilities. By integrating the detection function into the existing converter structure using standard measurement devices, the system achieves accurate fault location without requiring specialized expensive high-voltage detection equipment.
3Power
If the converter system operates with high voltage and high frequency to achieve high power density, then power density is improved, but the risk of insulation failure increases due to higher electric field stress
Solution Approach 1:
The patent implements continuous feedback monitoring of insulation status by measuring leakage current through connection elements in real-time. The detection system provides immediate feedback on insulation degradation, allowing the control system to take preventive actions such as adjusting operating parameters or shutting down affected modules before insulation failure occurs, thus maintaining reliability while operating at high power density.
Solution Approach 2:
The detection system provides early warning of insulation degradation by continuously monitoring leakage current trends. Before insulation failure occurs, the system can detect gradual increases in leakage current and implement protective measures such as reducing voltage stress on affected modules or initiating preventive maintenance, thereby cushioning against potential insulation failures and maintaining system reliability under high electric field stress conditions.
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 solution enables precise location of insulation abnormalities, simplifying maintenance work and reducing costs by allowing for targeted inspections and reducing the need for extensive high-voltage equipment usage.
Implementation Method 1
detecting a value reflecting a current flowing through the connection element
Data Source
AI summary
The invention discloses a method and device for detecting and locating insulation state of a conversion system, the conversion system including: a converter module including n conversion units, where n≥2, each conversion unit including a transformer including a first winding and a second winding; and a connection element connected between the first winding and the second winding of the transformer; the method for detecting and locating insulation state including comparing a value reflecting a current flowing the connection element before change of the state of at least one switch with a value reflecting the current flowing the connection element after change of the state of the at least one switch, and determining which of the n conversion units has insulation abnormality based on comparison result.