捕捉失步断面的实现方案及其仿真

Implementation Scheme and Simulation on Capturing the Out-of-step Interface

目前国内外的失步解列装置基本上是基于装置安装处的本地电气量去判断系统的失步特征,因而难以确定失步中心真正所在的失步断面联络线。系统失步后,周期积分无功总是倾向于流入失步中心所在的断面之中。随着光纤通信系统在现代电网中的广泛应用,文中提出了一种基于光纤互(纵)联,通过对系统双(多)端电气量的测量去寻找失步断面的新型失步解列方案。该方案通过对联络线双端电气量的采集,计算出发生有功过零的联络线上有功过零两次期间的瞬时无功积分值,并基于光纤通信系统寻找到联络线上计算出的无功积分值呈现出由两端流入的联络线即为失步断面联络线。通过对全网解列装置的振荡周期次数动作整定值的统一,实现同时断开失步机群间的电气联系,从而平息失步系统的振荡,防止事故扩大。该方案易于在工程中应用,可实现合理与有计划的解列。基于仿真研究验证了该方案的有效可实现性和优越性。

Nowadays the majority of out-of-step tripping systems installed throughout the world use local electrical measurements. Those schemes cannot determine the tie-line where the center of out-of-step really exists. When power system loses its synchronism, the period integral reactive power tends to flow into the interface of out-of-step. With the wide application of the optical fiber communication system in modern power systems, based on the inter (vertical) connection of optical fiber communication system, a new separation scheme based on dual (multi) terminal electrical parameter-based method for capturing the interface of out-of-step is proposed in this paper. Based on the electrical-parameter measurement at each terminal of the tie-line, the integral value of reactive-power of the tie-line whose active power flow is zero-crossing, is calculated during the course of active power crossing zero twice. Based on the optical fiber communication system, the tie-lines which have the characteristics of the integral value of reactive power flowing from their two terminals to the internals are chosen as the interface tie-lines of out-of-step. The interface of out-of-step can be tripped at the same time by setting the separation devices throughout the systems with the same value of the out-of-step period action-setting time. Therefore the asynchronous oscillation between neighboring interconnected power systems will be eliminated and the widespread outages will be avoided. The scheme is easy to be implemented and can carry out reasonable and designed system separation step. The simulation studies are given in the paper to show the correctness and the superiority of the proposed separation scheme.