A New Method to Measure the Residual Flux by Magnetic Sensors and a Finite-Element Model

Zhang, Haipeng; Long, Jiajie; Li, Xianhao; Xu, Ying; Shi, Jing; Ren, Li; Yang, Wentie; Wang, Zuoshuai; Chen, Meng

doi:10.1109/tim.2023.3279918

Cited by 4 publications

(1 citation statement)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To achieve controlled energization, prior knowledge of the residual flux is essential. To address this challenge, there have been publications focusing on measuring and estimating the residual flux [32][33][34][35][36][37][38][39], as well as pre-setting a known residual flux value [40]. Since the residual flux can be different before each energization, it becomes necessary to consistently measure or estimate it before energizing the transformer using these approaches.…”

Section: Introductionmentioning

confidence: 99%

Smart Switching in Single-Phase Grid-Connected Photovoltaic Power Systems for Inrush Current Elimination

Martínez-Figueroa,

Bogarra,

Córcoles

2023

Energies

View full text Add to dashboard Cite

Grid-connected photovoltaic (PV) power systems are one of the most promising technologies to address growing energy demand and ecological challenges. This paper proposes smart switching to mitigate inrush currents during the connection of single-phase transformers used in PV systems. An effective inrush current mitigation contributes to the reliability of PV systems. The inrush current severity is influenced by the pseudorandom residual flux at the transformer core and the energization point-on-wave. The most common approach to avoid inrush currents is controlled connection, which requires prior knowledge of the residual flux. However, the residual flux can differ in each case, and its measurement or estimation can be impractical. The proposed smart switching is based on a comprehensive analysis of the residual flux and the de-energization trajectories, and only requires two pieces of data (ϕRM and ϕ0, flux values of the static and dynamic loops when the respective currents are null), calculated from two simple no-load tests. It has a clear advantage over common approaches: no need to estimate or measure the residual flux before each connection, avoiding the need for expensive equipment or complex setups. Smart switching can be easily implemented in practical settings, as it considers different circuit breakers with distinctive aperture features, making it cost-effective for PV systems.

show abstract

Section: Introductionmentioning

confidence: 99%

Smart Switching in Single-Phase Grid-Connected Photovoltaic Power Systems for Inrush Current Elimination

Martínez-Figueroa,

Bogarra,

Córcoles

2023

Energies

View full text Add to dashboard Cite

show abstract

Residual flux density estimation of the three-phase transformer using BP neural network

Ren,

Liu,

Wang

2024

AIP Advances

View full text Add to dashboard Cite

When the off-line transformer is re-energized, the phase-controlled switching strategy can avoid the generation of inrush current by controlling the phase. To determine the closing phase, the residual flux density (Br) in the transformer core needs to be accurately measured. This paper proposes a Br estimation method for three-phase transformers based on the finite element method and BP neural network. Firstly, the direction of Br in each phase core is determined based on the transient current characteristics. Then, the three-phase transformer is simulated and the BP neural network is trained to estimate the Br based on the simulation results. The experimental results on a three-phase transformer show that the proposed method can accurately determine the direction and amplitude of Br in each phase of the three-phase transformer.

show abstract

Mitigating the Inrush Current of V/V Transformers Using Railway Conditioners

Aghazadeh,

Hajipour,

et al. 2024

IEEE Access

View full text Add to dashboard Cite

Inrush current is high-magnitude current drawn by power transformers upon energization. The severity of inrush current depends on factors such as the transformer's residual flux and the voltage phase angle at the energization instant. This paper proposes a flux matching method for the energization of V/V traction transformers to mitigate inrush current. This is achieved by adjusting the residual flux of the core to an appropriate reference value and then obtaining the proper energization instant. To this end, the method only requires knowledge of nominal voltage and excitation current, eliminating the need to acquire transformer's parameters/design information. The railway power conditioner, typically present at the low voltage side of the V/V transformer, is used as a current source to inject sinusoidal current into the transformer windings before its energization. The reference residual flux is calculated based on the circuit breaker operating characteristics. The energization instant is determined such that the adjusted flux density matches the steady-state flux expected with respect to the applied voltage. The proposed method is validated by conducting over 14,000 simulations under different conditions using PSCAD/EMTDC. The method is also implemented and successfully tested on a laboratory-scale test rig, which verifies its effectiveness in more realistic conditions.INDEX TERMS Inrush current, flux density, excitation current, railway power conditioners, V/V transformers.

show abstract

A New Method to Measure the Residual Flux by Magnetic Sensors and a Finite-Element Model

Cited by 4 publications

References 15 publications

Smart Switching in Single-Phase Grid-Connected Photovoltaic Power Systems for Inrush Current Elimination

Smart Switching in Single-Phase Grid-Connected Photovoltaic Power Systems for Inrush Current Elimination

Residual flux density estimation of the three-phase transformer using BP neural network

Mitigating the Inrush Current of V/V Transformers Using Railway Conditioners

Contact Info

Product

Resources

About