Saturation is a condition in which the magnets are fully transformer cores and generate maximum magnetic flux. Some parts affect the resilience and create distortions that can harm the heart. Core saturation can also ...Saturation is a condition in which the magnets are fully transformer cores and generate maximum magnetic flux. Some parts affect the resilience and create distortions that can harm the heart. Core saturation can also increase the temperature and magnetization current transformer. In this study, we proposed a measurement method to obtain the necessary parameters to calculate a reliable indicator of the state of the transformer core saturation. The main effects of nonlinear flow in the transformer core are saturation, eddy current and hysteresis. In saturation, the core transformer is as a source of generating harmonic currents, some of which will flow directly to the primary and secondary windings. The method is based on the magnetization current, the phenomenon of harmonics and power factor is evaluated by measuring the no-load current at three-phase transformer, with a high magnetic flux density imposed. Measurements were taken at each phase of the transformer core. The transformer is connected to a variable voltage variable frequency (VVVF) as a voltage source and the investigation carried out at various flux densities. The results showed that the magnetization current and harmonic phenomena increased significantly when the high magnetic flux density and vice versa injected with power factor declined sharply. This phenomenon can be used as an indication of saturation of the 3-phase transformer core.展开更多
The active saturated iron-core superconductive fault current limiter(SISFCL)is a good choice to decrease fault current.This paper introduced the principles and impedance characteristic of the active SISFCL.Then,it sho...The active saturated iron-core superconductive fault current limiter(SISFCL)is a good choice to decrease fault current.This paper introduced the principles and impedance characteristic of the active SISFCL.Then,it shows the current-limiting effects of the SISFCL.Besides,the impact of the active SISFCL on the distance protection of the EHV transmission line is evaluated.Based on that,the coordination scheme of the distance protections is proposed.A 500 kV double-circuit transmission system with SISFCLs is simulated by Electro-Magnetic Transients Program including DC(EMTDC).Simulation tests demonstrate the correctness and validity of theoretical analyses.展开更多
文摘Saturation is a condition in which the magnets are fully transformer cores and generate maximum magnetic flux. Some parts affect the resilience and create distortions that can harm the heart. Core saturation can also increase the temperature and magnetization current transformer. In this study, we proposed a measurement method to obtain the necessary parameters to calculate a reliable indicator of the state of the transformer core saturation. The main effects of nonlinear flow in the transformer core are saturation, eddy current and hysteresis. In saturation, the core transformer is as a source of generating harmonic currents, some of which will flow directly to the primary and secondary windings. The method is based on the magnetization current, the phenomenon of harmonics and power factor is evaluated by measuring the no-load current at three-phase transformer, with a high magnetic flux density imposed. Measurements were taken at each phase of the transformer core. The transformer is connected to a variable voltage variable frequency (VVVF) as a voltage source and the investigation carried out at various flux densities. The results showed that the magnetization current and harmonic phenomena increased significantly when the high magnetic flux density and vice versa injected with power factor declined sharply. This phenomenon can be used as an indication of saturation of the 3-phase transformer core.
文摘The active saturated iron-core superconductive fault current limiter(SISFCL)is a good choice to decrease fault current.This paper introduced the principles and impedance characteristic of the active SISFCL.Then,it shows the current-limiting effects of the SISFCL.Besides,the impact of the active SISFCL on the distance protection of the EHV transmission line is evaluated.Based on that,the coordination scheme of the distance protections is proposed.A 500 kV double-circuit transmission system with SISFCLs is simulated by Electro-Magnetic Transients Program including DC(EMTDC).Simulation tests demonstrate the correctness and validity of theoretical analyses.
