August 27，By Graduate School of Shandong University、Sponsored by the Postgraduate Affairs Department of the Party Committee，The 42nd issue of 2024 (the 1379th issue in total) "Jixiafeng" graduate student academic forum hosted by the School of Electrical Engineering was held in the lecture hall on the fourth floor of the Electric Power Building on Qianfoshan Campus。Invited to this forum is a professor from Imperial College London、Bikash Pal, Fellow of the Royal Academy of Engineering (FREng)，The topic of the lecture is "Dynamic Modelling for Analysis of Wind Farm and Grid Interaction"。The forum is hosted by Professor Guo Yifei，Professor Gao Houlei、Associate Professor Jin Chaoyang、International Exchange Specialist Wu Ke attended this event。

  Professor Bikash Pal mainly introduced the modal analysis method of wind farm and revealed the physical mechanism behind it，He started from a single-machine grid-connected system，First introduce the Type-III doubly-fed fan single machine grid-connected system，Indicates that the SMIB system has a frequency range of 10kHz-0.Multiple complex eigenvalues ​​at 06Hz，Corresponds to multiple modes，One of the high-frequency modes is related to the electrodynamics in the collector system cable；A certain mode near the fundamental frequency is associated with the dynamic characteristics of the generator stator，And this mode has a lower damping ratio；A certain low-frequency mode is associated with the mechanical dynamics associated with the generator，And at sub-synchronous speed，This mode has higher damping。At the same time，Professor Bikash Pal further explained the modal analysis results of the above doubly-fed wind turbine grid-connected system through frequency domain sweep results and time domain simulation results，And visually demonstrates the effectiveness of the modal analysis results used through different test cases。

  Professor Bikash Pal demonstrated the HVDC-VSC control system under different control parameters through simulation results、Direct drive fan GSC converter outer loop controller under different bandwidths、Modal performance and corresponding system dynamic response effects under different phase-locked loop parameters and different control strategy combinations，And to summarize the above results: Modes with frequencies above 2KHz are usually related to the electrodynamic dynamics of transmission lines；High frequency modes in the frequency range of 500Hz-2kHz are usually associated with transformers and transmission lines；The oscillation frequency of the intermediate frequency mode with a frequency of 50Hz-500Hz is usually close to 2、5、7th harmonic，Control with inverter、AC voltage, etc. related；Low frequency modes below 50Hz are often associated with interactions between wind turbines。Professor Bikash Pal also pointed out that with the refinement of the system dynamic model and the expansion of the grid connection scale，The system model will become larger and larger，At this time, it is necessary to reduce the order and simplify the model from the level of mathematical essence and underlying mechanism，He showed based on BT、ADI、RK、Comparison of frequency domain effects of IRKA order reduction method，Proved the effectiveness of the reduced-order model。

  Event last，Participating teachers and students took photos together。This issue of the "Jixiafeng" postgraduate academic forum ended successfully with warm applause from teachers and students。

About the speaker:

  Speaker Bikash Pal，Professor at Imperial College，Fellow of the Royal Academy of Engineering (FREng)，IEEE Fellow。Professor Bikash Pal is mainly engaged in power system stability、Research work related to control and computing，The research results have been widely used in Europe、Multiple countries and regions in South America。Due to its academic contribution and industrial influence in power grid stability control，Professor Bikash Pal was nominated as IEEE Fellow in 2013，And be elected as a member of the Royal Academy of Engineering in 2023。He served as Vice Chairman of IEEE PES、Positions such as Chief Editor of IEEE Transactions on Sustainable Energy，Still the United Nations、National Grid UK、Technical consultant for organizations and enterprises such as General Electric。