Phase-changing failure suppression method based on direct current prediction control

Abstract

The invention discloses a phase-changing failure suppression method based on direct current prediction control, and the method comprises the following steps of inputting direct current Id_inv at an inversion side and alternative-current bus three-phase instantaneous voltage ua, ub and uc; adopting a phase-changing failure prediction control module to detect the operation state of a current alternative-direct-current system so as to judge whether the phase-changing failure of an inverter happens or not; adopting a phase-changing failure prediction control module to predict and output an inverter trigger retardation angle variation value delta ainv_PREV; detecting a judgment signal of the phase-changing failure prediction control module, predicting a direct current setting value if the phase-changing failure possibly occurs to obtain a prediction value Id_PREV, and otherwise enabling the direct current to be a normal setting value Id_NOR; and outputting the Id_PREV and the delta ainv_PREV to a rectifier and inverter control system to be used for suppressing the phase-changing failure. Due to the adoption of the phase-changing failure suppression method, the phase-changing failure probability of a direct-current power transmission system can be reduced.

Description

technical field [0001] The invention belongs to the technical field of power system operation and control, and in particular relates to a commutation failure suppression method based on direct current predictive control. Background technique [0002] DC transmission has the advantages of large transmission capacity, low loss, rapid and flexible power regulation, and strong asynchronous connection capabilities, making it widely used in large-area grid interconnection and long-distance large-capacity power transmission. With the continuous improvement of my country's power grid construction level, DC transmission projects have become an important technical means to optimize the allocation of power grid resources and coordinate regional economic development. Commutation failure is a common typical system failure in HVDC transmission system, which will cause DC voltage drop and DC current increase for a short time; continuous commutation failure will easily lead to derating oper...

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Problems solved by technology

[0003] According to the constraints of the trigger delay angle range of the inverter working in the inverter mode, if the commutation voltage drops seriously, it may be difficult to ensure the successful commutation of the inverter if the maximum trigger delay angle is advanced; in addition, more commutation angles increase, it may also make the turn-off angle smaller due to the influence of the next commutation failure process, resulting in commutation failure. Only by reducing the trigger delay angle α and increasing the commutation angle μ to suppress the inverter commutation failure has its inherent limitation

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