Research On Control Characteristic Of AC/DC Power Grid Based On Different Simulation Models

With the popularization and application of Ultra High-Voltage DC transmission project, ac/dc hybrid power grid has become an important part of our country’s grid. Based on the power system electromechanical transient simulation software (PSD-BPA) and hybrid simulation of power system electromechanical transient and electromagnetic transient software (PSModel), according to different dc control system simulation model and ac/dc hybrid power grid, this paper analysis the parameter setting, optimization method and selection of simulation tool for steady operation of the practical grid, which has great significance to steady operation of the ac/dc hybrid power grid.For the practical engineering application of Siemens DC control system, based on the power system of electromechanical transient simulation software (PSD-BPA), analyzed the influence on starting value of voltage dependent current order limiter, the rated power link measurement time constant, and the disturbance of different frequency voltage. Studied the DC control system parameters impact on the large disturbance transient response characteristics of islanded system, which is based on Yunnan-Guangzhou UHVDC sending end islanded operation mode. On the basis, puts forward the optimization configuration scheme of DC control system parameter, simulation results demonstrate the optimization scheme can effectively reduce the reactive power demand of converting station after fault, which is helpful to enhance the voltage recovery level of islanded system, and guarantee the system safety and stable operation.For the practical engineering application of ABB DC control system, based on the power system of electromechanical transient simulation software (PSD-BPA), analyzed DC control system commutation failure prediction control function modules. During the disturbance process, increasing the phase margin by reducing inverter trigger angle a to implement prediction control. This control will change the reactive features of inverter station, even has influence on the voltage stability of received power grid. In this paper, we studied the influence of commutation failure prediction control and prediction parameters on nonlinear reactive curvilinear path and voltage stability of inverter station, proposed optimization measures to improve the large disturbance reactive demand characteristics prediction parameters of inverter station. The time domain simulation results of UHV DC received power grid under large disturbance verified the validity of optimized prediction control parameter can improve the voltage stability of received power grid.For the Fulong-Fengxian UHVDC sending power grid and Humeng-Yuxi UHVDC received power grid, under different simulation scales, analyzed differences between different simulation results under variety of fault conditions, proved different simulation models have effect on the accuracy of the simulation results, and verified the hybrid simulation of electromechanical transient and electromagnetic transient has high effectiveness and practicality in the ac/dc hybrid power grid faults especially in the case of received power grid faults.