Dynamic state estimation based protection using multi-section multi-layer frequency dependent line model for underground cables in MMC-HVDC grids

• Published in: Electric power systems research 2023-12, Vol.225, p.109836, Article 109836
• Main Authors: Wang, Binglin, Liu, Yu, Lu, Dayou, Pan, Ruiyu, Qiu, Jinhao
• Format: Article
• Language: English
• Subjects: Dynamic state estimation; Frequency dependent line parameters; MMC-HVDC grid; Underground cable protection
• ISSN: 0378-7796; 1873-2046
• DOI: 10.1016/j.epsr.2023.109836

•Improved dynamic state estimation (DSE) based protection method for underground cable in MMC-HVDC grids.•A multi-section multi-layer model is proposed to consider the distributed and frequency dependent line parameters.•A DSE based algorithm is proposed to formulate the protection criterion, including the trip decision and the fault pole identification.•The proposed protection can tolerate system noises, and only requires a relatively low sampling rate. A novel dynamic state estimation based protection (DSEBP) method is proposed for underground cables (UGCs), in modular multilevel converter based high-voltage direct current (MMC-HVDC) grids. The method uses the multi-section multi-layer model (MLM) to consider the frequency dependent (FD) line parameters, which are usually neglected by existing protection methods but will significantly impact their performances. The proposed method consists of the following steps: 1) the dynamic line model (DLM) of the healthy UGCs based on a multi-section MLM is proposed to consider the distributed shunt capacitive current and FD line parameters; 2) the DSEBP algorithm is utilized to solve the state variables and formulate the consistency indicator; 3) the trip decision is made when the inconsistency is observed multiple times, and the fault pole identification logic via residuals is presented to minimize the power outage zone. Simulation results present that the proposed DSEBP can dependably and quickly trip the faulted line during internal faults even with large fault impedance, and securely avoid mal-operation during external faults even for bolted faults close to line terminals. The proposed method uses a typical sample rate of 10 kilo samples/sec, and performs robustness towards parameter errors, measurement noises and synchronization errors.