A Data Redundancy Control Method for Flexible HVDC Converter Valves

Abstract

The invention provides a data redundancy control method for a flexible direct-current transmission converter valve. The method includes sequence control state machine and sequence control state data redundancy synchronous control, valve control and protection function enabling and disenabling data redundancy synchronous control, valve control sub-module bypass data redundancy synchronous control and loop current suppression controller data redundancy synchronous control; dual-redundancy communication design is adopted for two sets of valve control systems; the standby valve control system receives the operation state, control and protection enabling and disenabling, loop current suppression control integration and output and sub-module bypass data of the main valve control system, and therefore, the operation states and the control output of the standby valve control system and the main valve control system can be kept consistent, slight disturbance on a system caused by the redundancy switching of the system can be decreased to the greatest extent, when the standby system is powered off and restores power, the standby system can follow the operation state of the main system and stored historical data of important sub-module bypasses, and conveniences can be provided for the monitoring of the flexible direct-current system by an operator.

Description

technical field [0001] The invention relates to the technical fields of flexible direct current transmission and power electronics applications, in particular to a data redundancy control method for flexible direct current transmission converter valves. Background technique [0002] The flexible DC transmission system based on Modular Multilevel Converter (MMC) has the functions of supplying power to passive systems or weak AC systems, realizing rapid and independent control of active and reactive power, easy to form multi-terminal network systems, and low harmonic content. The advantages of being extremely low, without additional filters, and the number of cascaded MMC-HVDC sub-modules are not limited make MMC-based flexible DC transmission comparable to traditional DC transmission in terms of voltage level and transmission capacity. Compared with two-level and three-level flexible DC transmission, MMC-based flexible DC transmission not only greatly reduces the input cost o...

AI Technical Summary

Problems solved by technology

[0005] 1. In order to ensure the rigorous logic of the valve control sequence control, the sequence control state machine in the valve control needs to cooperate with the control sequence control state machine of the upper converter. , some of the primary equipment state quantities or analog quantities in the sequential control state machine can no longer meet the requirements of the sequential control from shutdown to operation step by step

[0006] 2. There is a probability that the operator of a certain set of valve control will forget to operate when the protection and control functions are switched on and off in the double set of valve control, which may lead to a large disturbance of the flexible straight system or a malfunction of the protection when the system is redundantly switched. risks of

[0007] 3. When the soft straight system is unlocked and the full power is running, the valve control A / B is different due to the delay and error of the bridge arm current sampling MU device A / B and the output of the circulation suppression control is different, and the upper converter controller A / B There is also an error in sending the modulated wave, so the switching disturbance caused by the asynchronous control output of the two systems during the redundant switching of the flexible straight system is relatively large

[0008] 4. Fault bypass of redundant modules may occur during the operation of the flexible straight system. The valve control needs to record the number of each bypass sub-module, bypass time, and bypass reason in real time. If the backup system is in power-off or maintenance status, bypass information cannot be stored

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