可控移相器对电网短路电流特性影响及限流控制策略

Influence of the Thyristor Controlled Phase Shift Transformer on Power Grid Short-Circuit Current Characteristics and Current Limiting Control Strategy

可控移相器在有效改善电网潮流分布、提升线路关键断面输送能力的同时,也会对电网短路电流特性产生一定的影响。根据可控移相器拓扑结构和工作原理,构建其三序分量等效模型;计及可控移相器接入对电网参数的影响,分析含可控移相器系统的短路电流周期分量和非周期分量衰减时间常数的变化规律;结合三相桥式整流电路和限流电感,提出可控移相器短路控制策略,增强可控移相器在应对系统短路故障时的安全性。通过广东电网典型场景算例,分别验证了可控移相器接入对电网短路电流特性的影响规律,以及短路电流控制策略的有效性。结果表明:装设可控移相器能够抑制系统短路电流周期分量,但会使得短路电流非周期分量衰减时间常数有所提升;所提短路电流控制策略能够增强可控移相器在应对系统短路故障时的安全性。

The thyristor-controlled phase shift transformer(TCPST)can effectively improve power flow distribution and increase capacity of key sections of the transmission line,but it also has some influence on short-circuit current characteristics of the power grid.For this reason,based on the topology and working principle of the TCPST,a three-sequence component equivalent model is constructed.Next,considering the influence of the access of the TCPST on the grid parameters,the shortcircuit current periodic component and the short-circuit current aperiodic component decay time constant of the system with the TCPST are analyzed.Combined with the three-phase bridge rectifier circuit and current limiting inductor,a short-circuit control strategy is proposed to enhance the safety of the TCPST in response to system failures.Finally,a typical example of Guangdong power grid is used to verify the influence of the TCPST on the short-circuit current characteristics of the power grid and the validity of the short-circuit current control strategy.Moreover,the proposed short-circuit control strategy can enhance the safety of thyristor-controlled phase shift transformer when dealing with short-circuit faults.