Abstract Accurate and efficient calculation of a transformer's magnetic field is fundamental for the rapid its losses, temperature rise, structural forces. However, existing numerical methods calculating harmonic product‐level transformer are time‐consuming fail to meet requirements digital operations maintenance. To address this, this paper first utilises method obtain snapshot matrix field. Subsequently, response surface model constructed using intrinsic quadrature theory radial basis...

This paper proposes a novel optimization method for fault current limiter (FCL) reactance configuration based on joint simulation and penalty function constraint optimization. By integrating MATLAB ATP simulation, the accurately derives conditions of objective function, providing critical data support process. To address challenges high computational complexity solution difficulties in constrained optimization, Penalty Function Method (PFM) is employed to transform original problem into...

ABSTRACT To accurately analyse the deformation of transformer windings under short‐circuit conditions, a three‐dimensional multiphysics field simulation model magnetic‐fluid‐thermal‐structural coupling is constructed. The current magnitude rated and conditions are calculated, magnetic distribution obtained based on current, loss calculated as heat source for temperature simulation. results electromagnetic force used initial structural to elastic‐plastic deformation, residual stress, winding...

Transformer is an important part of the power system, and its operation status related to safety stability system. In order effectively improve recognition accuracy abnormal transformer heat, improved YOLOv8 target detection algorithm model proposed. The introduction SPD-Conv convolutional layer improves model's ability small target, HAT hybrid attention mechanism Dyhead multiple even if information focusing on hot spot realized. multi-attention are introduced better spots. Finally, AHIPDNet...

A method combined ensemble empirical mode decomposition, Volterra model and decision acyclic graph support vector machine was proposed to improve adaptability, feature resolution, identification accuracy when diagnosing mechanical faults in an on-load tap changer of a transformer. In detail, the decomposition algorithm applied decompose multi-channel vibration signals switchover process changer. Then, for state established based on time-frequency characteristics obtained through use...

Abstract Transformers may suffer multiple short‐circuit impacts during long‐term operation, and axial instability is one of the typical types serious accidents caused by faults. The form winding‐block structure analysed, dynamic solution winding electromagnetic force obtained establishing three‐dimensional magnetic‐circuit‐force multi‐physical field coupling simulation model. influence strain rate on cushion block constitutive equation corrected, modified model verified impact test...

Partial discharge (PD) in electrical equipment is one of the major causes insulation failures. Fast and accurate positioning PD sources allows timely elimination faults. In order to improve accuracy detection, this paper mainly studies direction arrival (DOA) estimation ultrasonic signals based on a step-by-step over-complete dictionary. The simulation results show that step by dictionary can operation speed save signal processing time. Firstly, covering all angles space established...

The uncertainty of the evaluation information is likely to affect accuracy evaluation, when conducting a health power transformer. A multilevel assessment method for transformers proposed in view three aspects indicator criterion uncertainty, weight and fusion uncertainty. Firstly, selection conducted through transformer guidelines engineering experience establish model that can reflect defect type location. Then, Gaussian cloud used solve boundary. Based on association rules, AHP, variable...

Abstract Modular multilevel converters (MMCs) have been utilized in solid-state transformers (SSTs). With the increasing demand high-voltage power module MMC-SST, press-pack IGBTs are very promising. The poly-ether-ether-ketone (PEEK) frame is submodules of IGBT to withstand high voltage. electric field simulation this paper reveals that concentrates on surface PEEK frame. Thus, partial discharge characteristics under direct current (DC) voltage investigated by developed test bench. results...

To improve adaptability, feature resolution, and identification accuracy when diagnosing mechanical faults in an on-load tap changer (OLTC) of a transformer, the present research, wavelet packet energy entropy is used to describe information comprising vibration signal switch process OLTC, fuzzy weighted least squares support vector machine (CSA-fuzzy LSSVM) model based on cuckoo search algorithm proposed identify fault types. Specifically, according different importance sample data periods,...

Power transformer is a core equipment of power system, which undertakes the important functions transmission and transformation, its safe stable operation has great significance to normal whole system.Due complex structure transformer, use single information for condition-based maintenance (CBM) certain limitations, with help advanced sensor monitoring fusion technology, multi-source applied prognostic health management (PHM) an way realize CBM transformer.This paper presents method combine...

The existing research on the distribution characteristics of displacement and acceleration transformer axial vibration under short-circuit conditions is based ignoring damping parameters. An accurate description windings, especially for winding conditions, has a poor effect. In this paper, damping, stiffness, mass parameters between windings are comprehensively considered, classical “mass-spring-damping” mathematical model established. After solving, natural frequency, main mode shape,...

In order to realize distributed measurement of transformer winding temperature and deformation, a modification scheme with built-in optical fiber was designed. By laying single-mode multi-mode on the winding, Brillouin time domain reflection technique (BOTDR) Raman (ROTDR) are used measure strain complete more accurate deformation detection. The accuracy sensing this verified by simulation. Then, according scheme, model actually wound, rise tests were carried out. test results show that can...

This paper investigates the progressive loss of winding clamping pressure resulted from thermal aging in power transformers. Firstly, out-of-plane stress-strain characteristics pressboards are investigated experimentally and relationship between mechanical properties hours is established accordingly. Then, a thermal-mechanical model built to correlate time with temperature based on first-order reaction kinetics. Based above investigations, correlation obtained predicted. The results show...

Winding deformation caused by short-circuit is one of the main causes transformer damage. Even if successfully withstands impact, accumulative effect multiple impacts will cause sudden permanent winding. Internal winding a hidden fault due to visual blocking shell transformer, so it extremely important measure and analyze its influence. In this paper, SFSZ7-31500/110 was used for short-time impact tests. The measurability determined calculating difference between measured value reference...

Abstract Due to the strong coupling effect between internal magnetic field and structural of transformer, magnetic‐structural should be considered in axial vibration process winding short‐circuit impact. A 110 kV transformer is taken as research object. Firstly, modal characteristics are calculated using classical model, spatial distribution leakage flux density iron core window obtained based on image method, which used basis for calculating excitation electromagnetic force. With...

In recent years, as the power grid continues to expand, issue of asymmetrical short-circuit currents exceeding limits on 220 kV medium-voltage side has become increasingly severe, and traditional current-limiting methods have certain limitations. Therefore, this paper explores potential benefits feasibility installing a Fast Switching Fault Current Limiter (FSFCL) at neutral point transformer effectively limit side. The first analyzes performance FSFCL under different installation...

Abstract After the long‐term operation, multiple mechanical defects (i.e. loosening of winding and core) high‐voltage reactor will emerge. Mechanical conditions these critical components inside reactors differ vibration oil tank. Thus, in this paper, array sensors attached to external surface tank are utilized derive operation deflection shape, which provides effective‐rich information for diagnosis. The influence applied voltage deeply investigated, results indicate that frequency at 100 Hz...

The outage rate of high voltage power transmission lines caused by direct lighting has been analyzed and calculated, including straight lightning stroke on tower top (backstroke) round to conductor (shielding failure). Using the electrical geometry model exposure distance, shielding failure is calculated. Based principles IEEE flash program, across insulator string backstroke are Applying this method, rates a 220kV double circuit in Baoding, Hebei, China have According calculated results...

Abstract To solve the difficulty of eigenvalue extraction on‐load tap‐changer (OLTC) vibration signals, an method time‐frequency matrix based on Hilbert energy spectrum and spectral entropy is proposed in this study. By optimizing Hilbert‐Huang transform (HHT) algorithm, signal distribution obtained. The was extracted to characterize chaotic degree distribution, avoided problem inaccurate feature quantity such as similarity due minute time difference during acquisition. A new constructed by...

The high-voltage shunt reactor is essential in the power system, immensely significant to system's stable and safe operation. mechanical fault of core winding primary category reactor. In recent years, vibration noise problems have been widely concerned. Under long-term effect, internal components may become loose, even severe faults occur. this paper, reactor's mechanism discussed, an on-line monitoring system for vibro-acoustic signal developed. Four spectrum characteristics are extracted...