Single-Ended Dc Fault Location Method For Mmc-Based Hvdc Power System Using Adaptive Multi-Step Levenberg-Marquardt Algorithm

This article presents an accurate DC fault location method that applies parameter fitting. This technique first discusses the traveling waves (TWs) propagation process in the decoupled line-mode network. We obtain the exact fault distance equation based on the analytical expressions for the wavefront of backward line-mode voltage TWs. The adaptive multi-step Levenberg-Marquardt's (AMLM) algorithm is used for parameter fitting due to its fast processing speed and accuracy. The exact fault distance can then be estimated based on the fitting results. The proposed fault location method is verified using a three-terminal MMC-based HVDC system on a real-time digital simulator (RTDS). According to the experimental results, the proposed method accurately detects the fault location, with all estimated errors smaller than $1\%$, and can withstand 40 dB noise interference.