Guodian Institute of Science and Technology

[This corrects the article DOI: 10.3389/fbioe.2025.1430222.].

During system faults, power electronic converters in modern sustainable power systems activate low-voltage ride-through (LVRT) control strategies, which introduce second harmonic current into the power system. For transformer protection, the conventional inrush current identification method based on second harmonic current fails to adapt to the high harmonic conditions of electronic power-based sources in renewable energy systems. This paper proposes an identification scheme based on a modified MobileNetV4 (MNv4) architecture and multi-source electrical quantities. The experimental dataset is constructed through PSCAD simulation and engineering field data. The input feature combination including three-phase voltage, current and differential current is designed, which solves the defects of single feature in traditional methods. Experiments show that the MNv4 model delivers competitive performance in terms of accuracy and recall, while featuring a small number of parameters that make it suitable for resource-constrained embedded deployment. This research provides theoretical support and data paradigm for the engineering application of artificial intelligence in the field of relay protection.

ABSTRACT A novel filtering antenna based on spoof surface plasmon polaritons (SSPPs) is presented. The antenna has high suppression performance and tunable radiation nulls. The proposed antenna mainly consists of four parts, a metal ground, an SSPP‐based transmission line etched with slots, two driving elements on the upper and bottom surfaces, and three parasitic elements on the upper surface. By using the proposed SSPP‐based transmission line, good out‐of‐band suppression performance is achieved. Moreover, the out‐of‐band resonances are suppressed by etching slots in the SSPP structure. Besides, the radiation nulls of the antenna can be tuned by adjusting the key geometrical dimensions, which would be useful to fit different interference. The measured operating band is 2.130–2.606 GHz (20.1% at f 0 = 2.368 GHz), the in‐band average gain of the proposed antenna is 8.89 dBi with the peak realized gain of 10.55 dBi. The upper out‐of‐band suppression level is larger than 23.708 dB over 3.2–7.4 GHz band, while the gain response decreases rapidly from the maximum value (10.55 dBi at f = 2.52 GHz) to the minimum value (−67.315 dBi at f = 3.4 GHz).

This paper introduces the design and control method of the converter chain in a High-voltage cascade energy topology, and explores the cascading implementation scheme of High-voltage cascade energy. This power unit is applied to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$6-35 \text{kV}$</tex> High-voltage cascade energy converters. During the process, a High-voltage cascade energy converter chain power unit test platform and a high-voltage cascade platform were built to verify the design and operation scheme of the High-voltage cascade energy energy converter. The feasibility of the H-bridge cascaded power unit in the engineering High-voltage cascade energy storage application was verified during the experimental process.

The matrix operation modeling method of electric-thermal-natural gas interconnection multi-energy system based on graph theory is proposed in this paper. Firstly, on the basis of obtaining data information such as topological structure of electric-thermal-natural gas interconnection multi-energy system, parameters of energy conversion coupling equipment, coupling interconnection architecture and branch physical parameters, the overall comprehensive topological relationship of electric-thermal-natural gas interconnection multi-energy system is analyzed based on graph theory. Secondly, electric power system matrix operation model including DC power flow matrix operation model and AC power flow matrix operation model is established. Then, matrix operation model of thermal system is established, including matrix operation model of hydraulic model, matrix operation model of node pressure and pressure drop, and matrix operation model of flow and temperature in thermal system. Furthermore, matrix operation model of natural gas system including flow balance matrix equation model and pressure distribution matrix equation model is established. Finally, matrix model data information of each heterogeneous energy subsystem is output. The matrix model proposed has strong universality and wide application range, which can effectively provide theoretical guidance and reference for the rapid topological structure analysis, data sorting and induction of electric-thermal-natural gas interconnection multi-energy system at the system level, and save the engineering service site time and manpower and material resources.