Inverter Commutation Failure Prediction via Energy Accumulation
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Solution Overview
Problem
Existing detection methods for inverter commutation failure in HVDC transmission systems are not quick enough and prone to misjudgment due to disturbances, relying on conservative measuring methods and complex phasor calculations.
Innovation Solution
A commutation failure prediction method and device based on energy accumulation features of 12-pulse inverters, which collect instantaneous three-phase valve side current derivatives, determine the locations of incoming and ongoing valves, and calculate real-time and limit energy differences to predict potential commutation failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If measuring methods based on system features after commutation failure are used, then detection reliability is improved, but detection speed deteriorates
Solution Approach 1:
The patent calculates energy accumulation features in advance during normal operation and continuously monitors them to predict commutation failures before they occur. By performing preliminary calculations of energy accumulation based on valve-side currents and comparing against pre-determined thresholds, the system achieves both fast detection speed and reliable prediction, resolving the contradiction between speed and reliability.
2Measurement precision
If phasor calculation based measuring methods are used, then measurement precision is improved, but susceptibility to disturbance worsens
Solution Approach 1:
The patent extracts and utilizes only the essential energy accumulation features from valve-side currents, eliminating the need for complex phasor calculations. By focusing on the critical energy accumulation parameter and its comparison with threshold values, the method achieves sufficient measurement precision while being much less susceptible to disturbances from harmonics, noise, and system variations.
3Measurement precision
If complex phasor calculation methods are used, then detection accuracy is improved, but device complexity worsens
Solution Approach 1:
The patent replaces complex, computationally intensive phasor calculation algorithms with simple energy accumulation calculations and threshold comparisons. This substitution uses much simpler computational 'objects' (basic arithmetic operations) that are faster to execute and less prone to errors, while still achieving reliable commutation failure prediction through the physics-based energy accumulation model.
Data Source
AI summary
The disclosure discloses a commutation failure prediction method, device and storage medium based on energy accumulation features of inverter. The method includes the following steps: collecting instantaneous values of three-phase valve side current and calculating the derivatives of the three-phase valve side current according to the instantaneous values of three-phase valve side current; the derivative includes positive, negative and zero states; according to the derivatives of the three-phase valve side current, determining the locations of incoming valve and ongoing valve; based on the valve side current of the incoming valve and ongoing valve, calculating energy accumulation features of the 12-pulse inverter; predicting whether the commutation failure from the incoming valve to the ongoing valve will happen according to the states of the derivatives of the three-phase valve side current and the energy accumulation features of the 12-pulse inverter.