Abstract: The invention relates to Modular multilevel converter valve protection method, the modular multilevel converter valve consists of 6 arms, the arm includes sub modules, 1 arm is controlled by 1 control host, 6 control hosts is controlled by 1 summary control host, the method of the invention includes that the arm realizes locking sub module, bypass sub module, trip requests and system switching request and the summary control host implements summary and control response. The invention improves the reliability of two protection system through the use of dual redundancy protection method, clears the protection division through the layered protection frame of the upper summary control host and multi arm control host. And finally, it improves the whole safety and reliability of the modular multilevel converter valve.

Abstract: The present invention provides to a default current testing method of the high voltage direct current converter valve composited by impulse voltage. The technical scheme of the invention composites the symmetrical positive and negative voltage and the impulse into asymmetric positive and negative high voltage, it makes the test valve voltage accurately achieve required peak value at the set time. The test circuit is simple relatively; the high voltage source of the default current test circuit is instead by surge generators. The test method is flexible, safe, and suitable for different DC project converter valves.