US 12,316,102 B2
Method for detecting abnormal direct current voltage measurement in high voltage flexible direct current transmission system
Qinlei Chen, Guangdong (CN); Shuyong Li, Guangdong (CN); Qi Guo, Guangdong (CN); Libin Huang, Guangdong (CN); Xuehua Lin, Guangdong (CN); Zhijiang Liu, Guangdong (CN); Deyang Chen, Guangdong (CN); Chao Luo, Guangdong (CN); Guanming Zeng, Guangdong (CN); Mengjun Liao, Guangdong (CN); Lijun Deng, Guangdong (CN); Liu Cui, Guangdong (CN); Zhida Huang, Guangdong (CN); Haiping Guo, Guangdong (CN); and Tianyu Guo, Guangdong (CN)
Assigned to ELECTRIC POWER RESEARCH INSTITUTE. CHINA SOUTHERN POWER GRID, Guangdong (CN)
Appl. No. 18/014,022
Filed by ELECTRIC POWER RESEARCH INSTITUTE. CHINA SOUTHERN POWER GRID, Guangdong (CN)
PCT Filed May 18, 2022, PCT No. PCT/CN2022/093519
§ 371(c)(1), (2) Date Dec. 30, 2022,
PCT Pub. No. WO2023/109006, PCT Pub. Date Jun. 22, 2023.
Claims priority of application No. 202111517934.9 (CN), filed on Dec. 13, 2021.
Prior Publication US 2024/0097434 A1, Mar. 21, 2024
Int. Cl. G01R 31/08 (2020.01); H02H 7/26 (2006.01); H02J 3/36 (2006.01)
CPC H02H 7/268 (2013.01) [G01R 31/086 (2013.01); H02J 3/36 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for detecting abnormal direct current voltage measurement in a modular multilevel converter high voltage direct current transmission system, comprising:
obtaining a valve group voltage corresponding to an average value of sums of capacitor voltages of sub-modules of a three-phase bridge arm of a modular multilevel converter high voltage direct current converter valve from a valve base controller of an operating valve group at a detection pole in a modular multilevel converter high voltage direct current transmission system with a symmetrical bipolar structure;
collecting a first voltage at a pole bus direct current voltage measurement point and a second voltage at a neutral bus voltage measurement point of a duty control system at the detection pole based on direct current voltage measurement points set in the modular multilevel converter high voltage direct current transmission system with the symmetrical bipolar structure;
in a case that the modular multilevel converter high voltage direct current transmission system with the symmetrical bipolar structure is set with a direct current line side direct current voltage measurement point, collecting a third voltage at the direct current line side direct current voltage measurement point; and in a case that the modular multilevel converter high voltage direct current transmission system with the symmetrical bipolar structure is not set with a direct current line side direct current voltage measurement point, collecting a fourth voltage at a pole bus direct current voltage measurement point of a standby control system at the detection pole;
calculating a difference between the first voltage and a sum of the second voltage and the valve group voltage, filtering the difference with a first order low pass filter and calculating an absolute value of the filtered difference to obtain a fifth voltage;
in the case that the modular multilevel converter high voltage direct current transmission system with the symmetrical bipolar structure is set with the direct current line side direct current voltage measurement point, filtering a difference between the first voltage and the third voltage with the first order low pass filter and calculating an absolute value of the filtered difference to obtain a sixth voltage; and in the case that the modular multilevel converter high voltage direct current transmission system with the symmetrical bipolar structure is not set with the direct current line side direct current voltage measurement point, filtering a difference between the first voltage and the fourth voltage with the first order low pass filter and calculating an absolute value of the filtered difference to obtain a seventh voltage;
comparing the fifth voltage with the sixth voltage or comparing the fifth voltage with the seventh voltage, and performing a hysteresis comparison on a smaller one of the fifth voltage and the sixth voltage or a smaller one of the fifth voltage and the seventh voltage and a predetermined pole bus direct current voltage measurement abnormal detection threshold; and
in a case of meeting a first hysteresis condition of the hysteresis comparison, generating an abnormal pole bus direct current voltage measurement flag bit for the duty control system at the detection pole after a first predetermined delay.