Artificial intelligence identification method of external faults of conversion current bus of HVDC system

Abstract

The invention provides an artificial intelligence identification method of external faults of a conversion current bus of an HVDC system. The artificial intelligence identification method is characterized in that a wavelet-transform multi-scale decomposition algorithm is utilized to decompose system fault signals into different frequency sections, different wavelet energy skewnesses of different frequency-section signals are used as fault diagnosis feature vectors, and the fault diagnosis feature vectors are combined with a BP neural network to achieve accurate identification of fault types of an AC system. Compared with an AC system fault type identification method in the prior art, the method only needs to extract characteristics of a fault signal from the aspect of energy distribution, is not affected by the system operation mode, and is simple in operation, good in accuracy, and high in reliability.

Description

technical field [0001] The invention relates to an artificial intelligence identification method for external faults of a commutation bus in an HVDC system, and belongs to the field of high-voltage direct current transmission. Background technique [0002] The operation of the HVDC (high voltage direct current) transmission system is affected by the failure of the DC line, converter or AC system. In order to ensure the safe and reliable operation of the entire AC and DC system, it is necessary to detect the existence, type and occurrence of the fault at the initial stage of the fault. s position. [0003] The influence of the AC system fault on the DC system is effected by the change of the commutation voltage applied to the converter. When the AC system fails, the rate, amplitude and phase of the AC voltage drop will affect the operation of the DC system. When the AC system on the inverter side fails, the AC bus voltage of the inverter station decreases, which reduces the...

AI Technical Summary

Problems solved by technology

In some cases, commutation failure may recover by itself, but continuous commutation failure may cause the DC transmission system to block, and even endanger the stability of the entire system, causing greater harm

In the AC-DC hybrid operation system, the voltage collapse and the voltage oscillation caused by the control will cause the permanent commutation failure of the inverter

[0004] The multi-infeed DC transmission system has a larger transmission capacity and a more flexible operation mode, so the interaction between converter stations is more sensitive to commutation failure. The commutation failure of a converter station will not only cause its own DC The voltage fluctuation of the system may also cause commutation failure in multiple nearby converter stations, which will directly affect the stable operation of the AC and DC system, and even cause the entire system to collapse.

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