MODULAR MULTILEVEL CONVERTER VALVE PROTECTION METHOD

• US 20140002933A1
• Filed: 11/29/2011
• Published: 01/02/2014
• Est. Priority Date: 03/16/2011
• Status: Active Grant

• Current Assignee: China-EPRI Electric Power Engineering Co Ltd, Global Energy Interconection Research Institute, China Electric Power Research Institute (State Grid Corporation of China), State Grid Corporation of China
• Original Assignee: China Electric Power Research Institute (State Grid Corporation of China), State Grid Corporation of China
• Inventors: Gao, Yang, He, Zhiyuan, Yang, Yuefeng, Wang, Renqiu, Zhang, Xinggang, Xie, Minhua
• Granted Patent: US 9,373,950 B2
• Time in Patent Office: Days
• US Class Current: 361/18
• CPC Class Codes: H02H 3/085 making use of a thermal sensor, e.g. thermistor, heated by the excess current also responsive to the temperature of the protected device H02H5/041, thermal images H02H6/00
• CPC Class Codes: H02M 1/0003 Details of control, feedback or regulation circuits
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 1/325 with means for allowing continuous operation despite a fault, i.e. fault tolerant converters
• CPC Class Codes: H02M 7/4835 comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage

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.

Claims

1. A modular multilevel converter valve protection method, said modular multilevel converter valve consists of 6 arms, said arms consists of sub modules, is characterized that, said method includes following steps:

1) Connecting said arms with one end of arm control host, another end of said arm control host is connected with the summary control host;

2) When IGBT or drive temporary faults of sub modules occur, said arm control host will turn off the IGBT of sub modules;

when information receiving fault of sub module, the overvoltage fault of sub module, undervoltage fault of sub module, frequent check fault of sub module receiving the information, IGBT frequent fault or drive frequent fault occur, said arm control host will close the bypass switch of sub modules;

when sub module bypass switch refuses to trip, or the bypass number of sub module is too much, said arm control host will send trip request to the summary control host;

when the time of the arm control host receiving the upper information is out, said arm control host will send system switch request to the summary control host;

when the arm current is over large, said arm control host will send trip request with the thyristor trigger to the summary control host;

3) After step

     2), if the fault still exists, said arm control host will close the bypass switch of sub modules, summary and send fault signals to the summary control host;

4) The summary control host judges the arms trip request, the trip request with the thyristor trigger and system switch request according to arm control host feedback and arm current, and then carries out arms trip, the trip with the thyristor trigger and system switch.

2. The modular multilevel converter valve protection method according to claim 1, is characterized that, said temporary fault in said step 2) is referred that the faults will not occur 2 times continually.

3. The Modular multilevel converter valve protection method according to claim 1, is characterized that, said the time of the arm control host receiving the upper information is out in said step 2) is referred that it cannot receive the feedback 2 times continually.

4. The modular multilevel converter valve protection method according to claim 1, is characterized that, said arm current is over large in said step 2) is referred that the current is more than set maximum arm current.

5. The modular multilevel converter valve protection method according to claim 1, is characterized that, said the bypass number of sub module is too much in said step 2) is referred that it is more than set redundancy.

6. The modular multilevel converter valve protection method according to claim 1, is characterized that, said information receiving fault of sub module in said step 2) is referred that sub modules cannot receive signals.

7. The modular multilevel converter valve protection method according to claim 1, is characterized that, said the trip request with the thyristor trigger in said step 2) is referred that requesting to trip breaker of the converter and open the thyristor of each sub module at the same time.

8. The modular multilevel converter valve protection method according to claim 1, is characterized that, said arm trip in said step 2) is referred to open the breaker of the converter.

9. The modular multilevel converter valve protection method according to claim 1, is characterized that, said the arm control hosts and the summary control host are all valve base control device;

said valve base control device includes a power supply, an interface board and a central processing unit;

the power supply, the interface board and the central processing unit are connected with the fiber through a backplane.