Abstract
In this paper, a broadband circuit model of a potential transformer (PT) based on fractional calculus and circuit augmentation method was proposed to improve the high frequency characteristic while providing physical significance of the existing traditional equivalent circuit model with simple structure. In order to comprehensively reflect on the characteristics of hysteresis of the iron core , a fractional model of the magnetic hysteresis loop in iron core measured by a no-load experiment was set up instead of the single-value magnetization curve of previous model. Besides, the original equivalent circuit model was calculated at low frequencies, and the circuit augmentation method (CAM) was employed to extend the compatibility of the original equivalent circuit model in the wide range of frequency. The element values were calculated by the Brune method of synthesis. For validity, comparisons between the simulation and experiment of a 10 kV single-phase oil-immersed PT with lightning overvoltage and switching overvoltage were conducted, respectively. The results showed that the broadband model presented in the paper had good accuracy while reserving the physical significance of original equivalent circuit model.
Highlights
Power transformer is one of the most important and critical devices in power systems [1, 2]
The potential transformers (PT) with lightning overvoltage and switching overvoltage were measured followed by comparison of the simulation result
The lightning overvoltage waveform is shown in Fig. (13), and the switching overvoltage is shown in Fig. (14)
Summary
Power transformer is one of the most important and critical devices in power systems [1, 2]. Traditional equivalent circuit model with simple structure and explicit physical significance correlate merely well with the measured parameters at lower frequencies. It deviates at higher frequencies (e.g. lightning overvoltage and switching overvoltage), the existing models cannot meet the stringent demand of production and movement. There are several key factors such as magnetic saturation, hysteresis and eddy current for the nonlinear phenomena of iron core. Lucas et al proposed using nonlinear inductance and nonlinear resistors in parallel connection to simulate the iron core magnetization process 1992 [14]. A fractional order model for the magnetic hysteresis loop of iron core was established
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
