Yixiang Xia

Addressing the challenges brought by complex hybrid ring networks in fault section location and accurate location, this paper proposes a hybrid transmission network traveling wave (TW) location method based on fault deduction and wave speed optimization. First, the paper analyzes the TW propagation process and establishes equivalent models for each stage of the propagation process, deriving initial TW relationships between measurement points. Based on this, the fault deduction algorithm determines the TW propagation paths, enabling network decomposition of complex hybrid ring lines. Combining the concept of virtual fault (VF), a fault section location model is established, and the fault section is determined by maximizing the similarity of VF waveforms. Utilizing the TW arrival time in non-fault areas after network decomposition, a TW speed optimization model is established to obtain the optimal TW speed solution for the region, achieving accurate location. Verified by the PSCAD simulation platform, this method can accurately locate the fault section and determine the optimal TW speed in complex hybrid ring network scenarios, achieving accurate fault location.

To address the issues of location accuracy in traveling wave (TW) network location methods, which are susceptible to clock synchronization errors and TW speed inaccuracies. We propose a TW network location method based on virtual fault time difference information, simulating the propagation of TWs using virtual faults (VFs). Theoretically, the study analyzes the impact of transition resistance and TW heads (TWHs) aliasing on TWHs calibration, proposing an optimal effective time difference criterion that is unaffected by these factors. Algorithmically, VFs are first set in the faulty line, and a path search algorithm is used to obtain all TWH paths from the VF point to the measurement points. Subsequently, based on the optimal effective time difference selection criteria for different fault areas, steps such as filtering VF wave head paths and simulating virtual fault TWHs yield the optimal time difference matrix for the VFs. The accuracy of the VF location is assessed by calculating the degree of difference between the time difference information of virtual and real faults. An optimization algorithm continuously adjusts the VF point location and TW speed, gradually converging the VF point to the real fault point until they coincide, at which point the VF location corresponds to the real fault location. Verified by the PSCAD simulation platform, the proposed method can achieve precise fault location under various fault types, transition resistances, and noise interferences.

To prevent the further escalation of multiple faults in transmission networks, which could lead to severe accidents, this article proposes an accurate fault location method for multiple faults using simulated virtual faults (VFs) traveling waves. The method is validated by comparing it with real faults wavefront sequences. Initially, the article analyzes the interactions and aliasing phenomena of traveling waves from different fault sources at measurement points based on their propagation characteristics. It also discusses the relative temporal and amplitude relationships between different fault wavefront sequences. Then, a matching method between VF wavefront sequences and real fault wavefront sequences is proposed, and a wavefront sequence matching ratio is formulated to quantify the location disparity between the VFs and real faults. Finally, the article introduces a multiple faults location mechanism and achieves accurate fault location for multiple faults using the dynamic virtual faults traveling wave location method. Verified through the PSCAD simulation platform, the proposed method is unaffected by errors in wave propagation speed, eliminates the need for terminal traveling wave measuring equipment, and can accurately locate up to three faults with a location error less than 100 m.

This study aims to address the challenge of fault location in distribution networks with closed-loop structures. We propose a comprehensive method that focuses on two aspects: traveling wave head calibration and fault location. By analyzing the propagation properties of hybrid lines traveling waves, we demonstrate the feasibility of optimizing wave speed using time difference measurements. To solve the time calibration problem of weak fault signals, we utilize the signal cumulative deviation curve to select the time window of fault mutation, and then develop a novel wide scale time window difference operator for accurate calibration. Finally, we use a positioning method based on dynamic virtual faults to optimize wave speed and accurately locate faults in both overhead and cable lines. We build an improved IEEE 118 node network using power system simulation software (PSCAD) for simulation verification, which shows that our proposed method can accurately calibrate the initial wavefront time of fault traveling waves and precisely locate the fault positions.