Research On DC Transmission Simulation Modeling Method Based On Model Segmentatio

With the support of the "dual carbon" strategic goal,new energy generation will undergo large-scale grid connection,DC transmission will develop rapidly,and new power electronic equipment will cover various electrical scenarios.These will bring unpredictable changes to the primary operation mechanism and secondary control characteristics of the DC transmission system.Studying the impact and impact of these changes on the power grid will greatly deepen the dependence on the accuracy,stability,and integrity of power simulation.The many challenges brought by the new characteristics of a series of new power systems will put forward higher requirements for real-time simulation of DC transmission.When implementing electromagnetic transient simulation for direct current transmission systems,the complex combination of power electronic devices and frequent switching of taps can lead to variable system topology,resulting in a heavy burden on the simulation hardware to update the admittance matrix in real-time.The traditional single CPU electromagnetic transient simulation is far from meeting the development needs of fast real-time simulation of DC transmission.The effective method to fundamentally solve the simulation problem of multi switch large-scale systems is to segment the model and then implement parallel simulation with separate cores.In order to achieve real-time simulation of electromagnetic transients in direct current transmission with multiple switches and power electronic components,the main work of this paper is as follows:Firstly,the current research status of DC transmission,model segmentation,and interface algorithms at home and abroad is elaborated;Furthermore,the underlying modeling and calculation principles of electromagnetic transient simulation in power systems were introduced.Taking the three subsystems obtained after segmentation as examples,two simulation temporal logics,serial and parallel,were discussed respectively;Then,the principles of four commonly used interface algorithms were explained,and their advantages and disadvantages in terms of accuracy and stability were summarized.The applicable scenarios of each interface algorithm were discussed separately;Secondly,in response to the ideal transformer model method used in this article,stability criteria for several simple models were analyzed for serial and parallel simulations.Considering the shortcomings of stability analysis,several methods that can improve the stability and accuracy of the simulation system were introduced;Finally,the model segmentation interface algorithm is applied to different power scenarios for real-time simulation: the ideal transformer model method is proposed to achieve the function of interface voltage and current transformation,and the Fourier decomposition and reconstruction method is used to compensate for interface voltage delay.Then,the interface is combined with tap control and applied as an on load voltage and current transformer to the high-voltage DC transmission model,Based on a single core RT-LAB realtime simulator,the effectiveness of the proposed method for high-voltage direct current transmission systems with multiple tap switches is verified through comparison in the limited simulation hardware resources;The ideal transformer model method and the long transmission line decoupling method were applied to the ultra-high voltage direct current transmission model for AC and DC system segmentation,respectively.Then,a split core parallel real-time simulation was implemented based on the UREP real-time simulator to compare and verify the correctness and applicability of the proposed method for real-time simulation of ultra-high voltage direct current transmission with multiple power electronic components under different steady-state and transient conditions.