考虑锁相环和换相失败的LCC-HVDC闭环动态相量仿真模型

Closed-loop Dynamic Phasor Simulation Model of LCC-HVDC Considering Phase-locked Loop and Commutation Failure

为解决交直流混联系统暂态响应难以快速精确求解的问题,文中基于动态相量法基本原理,对电网换相换流器型高压直流输电(line commutated converter high voltage direct current,LCC-HVDC)全系统进行详细的建模推导。首先建立含锁相环的换流器动态相量模型,通过将锁相环输出与改进开关函数相结合,准确还原换流器的工作过程,提高计算的速度和精度。随后,通过对直流线路和控制系统的精确建模,实现了系统的闭环计算。同时,针对逆变侧易出现的换相失败情况,提出复合判据和开关函数修正法对其进行快速判断和处理,拓展模型的适用性。将所建模型应用于CIGRE Benchmark标准直流系统,多故障类型下的仿真结果进一步证明了其相较于传统动态相量模型的优势。

In order to solve the problem that the transient response of AC/DC hybrid system is difficult to calculate quickly and accurately, a detailed modeling of the entire LCC-HVDC system was carried out based on the dynamic phasor method in this paper. Firstly, the dynamic phasor model of converter with phase-locked loop(PLL) was established. By combining the output of PLL with an improved switching function, the working process of the converter was accurately restored, and the calculation speed and accuracy were improved. Subsequently, through accurate modeling of the DC line and control system, the closed-loop calculation of the system was realized. At the same time, for commutation failure that is easy to occur on the inverter side, a composite criterion and a switching function modification method were proposed to judge and process it quickly, which expands the applicability of the model. The model built in this paper was applied to the CIGRE Benchmark standard system, and the simulation results under multiple fault types further proved its advantages over traditional dynamic phasor models.