高压直流输电系统中次同步振荡研究综述

Abstract

由于高压直流输电(HVDC)技术有着损耗小、线路造价低等优点，在我国电力系统中被广泛采用。但HVDC与汽轮发电机组轴系相互作用可能产生次同步振荡(SSO)，影响系统的安全稳定运行。本文以直流输电系统对次同步振荡的影响和抑制方法为立足点，对高压直流输电系统中次同步振荡研究进行综述。首先，比较了几种常用的HVDC数学建模方法。然后，总结了换流器触发方式、控制模式及控制参数等对次同步振荡的影响，并介绍了多直流运行、串补或其他电气设备与HVDC联合运行时的系统的次同步振荡特性。接着指出在HVDC整流侧的定电流控制器里附加次同步阻尼控制是一种最常用的抑制SSO的策略，并比较了常见SSDC的设计方法。本文还介绍了新型直流输电VSC-HVDC以及风电加入系统后对次同步振荡的影响。最后，结合电力系统的发展要求对高压直流输电系统的次同步振荡研究方向做出展望。 HVDC has been applied widely in power systems because it has some merits such as low loss, low line cost and so on. However, interaction between HVDC converters and turbine generator shaft system may cause subsynchronous oscillation (SSO) which threats the safety and stability of power systems. This paper is intended to make a survey on SSO in HVDC by proceeding from the influence of HVDC on SSO and corresponding suppression strategy. The common methods of HVDC mathematical modeling are compared first. Secondly, the paper summarizes the effect of HVDC converter trigger modes, control modes and control parameters on SSO. The SSO characteristics of multiple HVDC and HVDC combined operation with series compensation or other electrical equipment is also introduced. Then the most common suppressing strategy that is installing a supplementary subsynchronous damping control (SSDC) in the constant current controller of rectifier is pointed out. And the design approaches of SSDC are compared. Besides, the influences of VSC-HVDC and HVDC system including wind power on SSO are presented. Finally, vistas of research are projected into the future.