Wind Turbine Transformer Fault Detection via Zero-Sequence Voltage
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Solution Overview
Problem
There is a need for a low-cost, reliable method to detect faults in wind turbine transformers, particularly in identifying conditions such as open phases, voltage unbalance, and frequency deviations at both low and high voltage sides, which are not effectively addressed by existing fault detection systems.
Innovation Solution
A detecting device comprising a voltage detection device and a logic circuit that identifies faults by monitoring zero-sequence voltage, voltage unbalance, over/undervoltage, and Total Harmonic Distortion (THDv) at the low and high voltage sides, with a control device to interrupt the transformer output line based on detected conditions, including external trip signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If voltage measurement is performed only on the low voltage side of the transformer, then the device complexity is reduced and cost is lowered, but the measurement precision and reliability of fault detection deteriorates because faults at the high voltage side cannot be accurately identified
Solution Approach 1:
The patent uses zero-sequence voltage as an intermediary parameter that indirectly reflects the state of the high voltage side. By measuring zero-sequence voltage at the low voltage side, the system can infer faults at the high voltage side without direct measurement, thus maintaining low device complexity while improving fault detection accuracy.
Solution Approach 2:
The patent replaces direct electrical measurement at both voltage sides with a substituted measurement approach using zero-sequence voltage analysis. This substitution allows the system to detect high voltage side faults through low voltage side measurements, reducing the need for complex dual-side measurement systems.
2Reliability
If comprehensive fault detection parameters are monitored, then the reliability of fault detection is improved, but the device complexity and cost increase due to additional sensors and processing requirements
Solution Approach 1:
The patent makes the voltage detection device multi-functional by enabling it to detect multiple types of faults (phase losses, voltage unbalance, frequency deviations, THD) using a single measurement point at the low voltage side. This universal detection capability improves reliability without proportionally increasing device complexity.
Solution Approach 2:
The system uses logic circuit feedback to analyze detected voltage parameters and determine the type and location of faults. The feedback mechanism processes zero-sequence voltage and voltage unbalance measurements to provide reliable fault identification, improving detection reliability through intelligent processing rather than additional hardware.
3Measurement precision
If the detecting device monitors multiple fault conditions including zero-sequence voltage, voltage unbalance, and frequency deviations, then the measurement precision of fault detection is improved, but the difficulty of detecting and measuring increases due to the complexity of analyzing multiple parameters
Solution Approach 1:
The patent segments the fault detection process into distinct analysis modules within the logic circuit, each handling specific parameters (zero-sequence voltage analysis, voltage unbalance analysis, frequency deviation analysis). This segmentation makes the complex multi-parameter detection more manageable and easier to implement while maintaining high measurement precision.
Data Source
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AI summary
It is described a detecting device and a method for detecting a fault in a transformer (10) of a wind turbine (1), wherein the transformer (10) transforms a lower voltage, which is output from a generator (5) of the wind turbine(1) to a low voltage side of the transformer (10), to a higher voltage, which is output from the transformer (10) at a high voltage side, the detecting device comprising: a voltage detection device (11) configured to detect a voltage at a first node (12) at the low voltage side of the transformer (10); a cur- rent detection device (11) configured to detect a current at a second node (13) at the high voltage side of the transform- er (10). The detecting device is configured to detect the fault in the transformer (10) based on the detected voltage and the detected current.