随着高电压、大功率电力电子设备不断出现并投入实际电网运行，大规模交直流电网的稳态与动态特性发生了深刻的变化，交直流输电系统之间的耦合更加紧密。提高电力电子开关设备的仿真准确性，以及直流近区的交流电网仿真精度，并开发实用的全电磁暂态仿真程序，成为大规模交直流系统规划设计、调度运行亟待解决的关键问题。本文从以下几个方面对电力系统全电磁暂态仿真的关键问题进行了深入研究：1、模型方面，同步发电机具有很强的非线性。本文提出了一种基于互感模型的同步发电机电磁暂态模型和实现方法，该模型具有恒定的接口阻抗，不必反复修改网络的导纳矩阵，准确性介于机电暂态模型和电磁暂态模型之间，且能直接利用已有的发电机实测建模成果。2、算法方面，本文基于龙格库塔理论和TR-BDF2方法，提出了一种三级半隐式龙格库塔（3-stage singly diagonally implicit Runge-Kutta，3S-ESDIRK）显隐式积分算法。该算法在满足电磁暂态（Electromagnetic Transient，EMT）类程序架构的同时，还具备正常计算过程中的L稳定特性和全局的2阶计算精度。针对同步发电机等非线性模型，构建了一套带误差估计的非线性显式计算公式，使得算法的收敛性和计算精度得到了保证。3、初始化方面，对常规直流潮流模型换相过程导致的谐波进行了详细分析，改进了其潮流计算公式，可以将无功功率偏差从3.5%降低到1%左右。提出了特高压直流输电系统三阶段初始化方法，使其初始化所需仿真时间缩短。提出了一种基于分网和钳位电源的大电网初始化策略，并利用华东电网算例验证了初始化策略的有效性。4、仿真架构方面，针对通用计算机计算的问题进行了详细分析。基于分布参数共享内存池以及Socket通讯的数据交换方式下，提出了一种低密度分网串并行混合的计算架构，该架构具有一定的通用性，既适用于普通的个人计算机，也适用于稍复杂的机群计算。利用华东电网算例验证了大规模电力系统全电磁暂态计算的可行性。
As the development of power electronic equipment and their application into the power grid, the steady-state and transient characteristics of large-scale AC/DC power grid have great changes. The electromechanical transient simulation using the quasi steady-state model of HVDC and the detailed electromagnetic transient modeling only for HVDC cannot meet the requirements of the stability analysis. In order to improve the simulation accuracy of the power electronics, a practical full electromagnetic transient simulation tool should be built for planning, design, scheduling and operation of large-scale AC/DC interconnected power system.Firstly, synchronous generator is the most important component in the study of large-scale power system stability, and its model has strong nonlinearity. The main contribution of this paper is to propose a mutual inductance based practical model and its implementation in electromagnetic program. The proposed model has a constant interface impedance, so the admittance matrix of the network does not need to be modified repeatedly. And it has appropriate accuracy, which is between accuracy of electromechanical transient model and accuracy of electromagnetic transient model. Secondly, based on the Runge Kutta theory and TR-BDF2, this paper proposes a 3-stage singly diagonally implicit Runge Kutta algorithm (3S-ESDIRK). The algorithm not only suits for the EMT program architecture, but also has the L stability characteristic in normal stage and 2 order calculation precision during the whole process. An AC/DC hybrid example is used to show that the 3S-ESDIRK method can maintain the accuracy of 2 order during the whole calculation process and will not create the calculation error to the whole network. Then, based on 3S-ESDIRK, a novel explicit calculation formula for the nonlinear detailed model of synchronous generator is constructed, which improves the convergence and calculation accuracy of the nonlinear model.Thirdly, the conventional power flow model of HVDC is analyzed in detail, and its power flow model is modified. In the new model, the commutation process of the converter is considered in the formula of the effective value of AC current. From the analysis of the actual electric network example, the formula can reduce the reactive power error from 3.5% to about 1%. Then, according to the characteristics of different power grid components, this paper proposes a strategy of network initialization, which uses the way of network division and clamp voltage source to initialize different characteristics of equipment. An example of East China power grid is used to verify the effectiveness of the initialization strategy.Lastly, the paper discussed the problem of efficient computing in general-purpose computer, based on the distributed parameter shared memory pool and the data exchange mode of socket communication, this paper proposes a serial and parallel hybrid computing architecture with low-density network splitting. This calculation method has generality and is suitable for both personal computers and complex cluster computing. At the same time, the feasibility of large-scale power system electromagnetic transient calculation is verified by East China Power Grid example.
