【作者】 李明；

【导师】 赵书涛； 刘文焯；

【作者基本信息】 华北电力大学 ， 工程硕士（专业学位）， 2018， 硕士

【摘要】 特高压直流输电近几年在我国迅速发展,已经到了全国联网、大规模应用的阶段。这使得交直流电网对整个网架的运行特性产生了较大的影响,因此电网大规模的交直流仿真成为了迫切的需求。以直流部分为电磁暂态、电网部分为机电暂态结合进行混合仿真,既能保证准确性又能保证计算规模,其中直流部分建模直接影响到仿真的准确性。特高压直流有着高度可控性,能通过控制系统快速改变其运行状态,因此建立直流控制系统的准确仿真模型对交直流电网特性的影响有着重要意义。特高压直流输电控制分为站控、极控、和阀控。本文首先详细阐述站控的直流的启停控制、功率的反转控制、指定功率控制、无功功率控制;极控的电压计算、电流计算、低压限流、功率震荡阻尼;阀控的触发角控制、阀组启停控制、换流变分接头控制的原理。然后介绍电科院的PSModel混合仿真软件的特点和建模方法,并以之为平台,将上述主控、无功控制、频率偏差限制控制、功率振荡抑制控制、极功率转移控制、电流裕度补偿控制、低压限流VDCL模块、最小触发角控制、换相失败预测控制、最大触发角控制、Gamma0控制、变压器分接头控制进行建模。根据上述分层控制原理搭建了整套特高压直流输电的控制系统。该模型对不影响直流特性的部分进行了简化,在保证仿真特性正确的同时减少了计算机运算量提高了仿真效率。最后以我国已经投产运行的复龙-奉贤±800kV特高压直流输电工程为例建立了一次系统,并通过接口将所建直流与交流电网进行连接。模拟整流侧交流电网故障、逆变侧交流电网故障,验证了直流控制系统的动态特性。将仿真与实际录波的曲线对比,结果表明所建直流控制系统的运行特性符合实际。本文工作对于特高压直流控制系统的建模和交直流仿真的应用有着参考意义。更多还原

【Abstract】 UHVDC transmission has developed rapidly in China in recent years,and it has come to the stage of nationwide networking and large-scale application.This makes the AC and DC power grid have a great influence on the operation characteristics of the whole network frame,so the large-scale AC / DC simulation of the power grid has become an urgent demand.The DC part is electromagnetic transient,and the grid part is electromechanical transient combination.The hybrid simulation can not only guarantee accuracy,but also ensure the computation scale.DC part model ing directly affects the accuracy of simulation.UHVDC has high controllability and can quickly change its running state through the control system.Therefore,it is very important to establish the accurate simulation model of DC control system for the influence of AC and DC power network characteristics.UHVDC power transmission control is divided into station control,pole control,and valve control.This paper describes the DC station control start stop control,power control,power control,reverse the specified reactive power control;voltage control calculation,current calculation,low voltage current limiting and power oscillation damping control valve;the trigger angle control valve group,start stop control principle,converter transformer tap control.Then introduces the characteristics and modeling methods of PSModel hybrid simulation software developed by EPRI,and takes it as the platform build the main control,reactive power control,frequency control,power oscillation suppression limit deviation control,power control,pole transfer current margin compensation control,low voltage current limiting VDCL module,minimum trigger angle control,prediction control,maximum firing angle control,Gamma0 control,transformer tap control model of commutation failure.A whole set of UHVDC transmission control system is set up according to the above stratified control principle.The model simplifies the part that does not affect the DC characteristics.It reduces the computational complexity and improves the simulation efficiency while ensuring the correctness of the simulation characteristics.At last,a system is established based on the operation of Fulong Fengxian + 800 kV UHVDC transmission project which has been put into operation,and the DC and AC power grid are connected through the interface.By comparing the curves between the simulation and the actual recorded wave,it verifies the effectiveness of the DC control system.The results show that the operating characteristics of the DC control system are in accordance with the actual conditions,and can be used in the study of DC characteristics and the mechatronics and electromagnetic hybrid simulation of large power grid.This work is of great significance to the modeling and AC / DC simulation of UHV DC control system.更多还原