Research On The Model Of HVDC Transmission Control System

As we all know,with the increasing transmission capacity,we are faced with unprecedented challenges in how to solve many problems in the process of power transmission better and transport power more stably.Therefore,it is increasingly important to understand the structural characteristics and control characteristics of HVDC transmission systems accurately.The control system is the highest priority in the entire transmission system.It is necessary to establish corresponding simulation software to study this control system better.There are many simulation softwares be used by power system commonly,such as PSAPAC,EMTP/ATP,BPA,etc.However,with the continuous development of the power industry,the relative lack of power equipment simulation software for the simulation software and the environment for simulation modeling are not clear enough.The simulation software PSCAD/EMTDC used in this paper has many advantages in terms of simulating the interface environment or updating the components needed to simulate the power system.For example,its entire modeling and simulation interface is very concise and clear,and its operation is simple and flexible.Firstly,this paper describes the structure and principle of HVDC transmission system briefly and explains the control system modules in the system.This paper also introduces principle and operation mode of the control methods that often used by HVDC transmission system.The article uses PSCAD / EMTDC simulation software to set up the simulation of the model and control method of the high-voltage DC primary system of controlled object.This intuitive understanding of the system model is not only conducive to the study of the operating process of the HVDC transmission control system,but also helps us find more rules from its control process.It is important for our electricity research.In the fourth chapter of the article,through the cooperation between the control modules of various systems,we have established and operated a simulation model for several phenomena with the highest probability of occurrence in HVDC transmission systems.For example,common single-phase and two-phase grounding and DC grounding phenomenon.After analyzing the simulation process and results,it is possible to clearly observe the control process and control characteristics of the inverter control and reactive power control.The flip-flop controls the reaction faster and reactive power control through a switching filter is slower.The two of them cooperate with each other and can restore the HVDC system to normal stable operation after a failure in a very short time.It also provides a basis for future research on better control strategies and further improvement of the control system’s capabilities.It is also good for the stability of the HVDC transmission system and it can accumulate some experience for the future research.