混合多馈入直流输电系统连续换相失败抑制策略

Continuous commutation failure suppression strategy in hybrid multi-infeed HVDC transmission system

随着直流输电工程应用的增多,一旦基于电网换相换流器的高压直流(LCC-HVDC)发生连续换相失败,将会对电力系统的稳定运行产生极大影响。为了抑制混合多馈入直流输电系统中LCC-HVDC的连续换相失败,文中从提升LCC-HVDC换相电压的角度出发,提出混合多馈入直流输电系统的协调控制策略。该策略根据LCC-HVDC的实时无功缺额动态调节基于电压源换流器的高压直流(VSC-HVDC)输出的无功功率与有功功率,从而改变其暂态稳定运行点。通过该策略的协调控制可以抑制LCC-HVDC的连续换相失败以及较大限度提升直流输电系统有功功率的传输能力。最后在PSCAD/EMTDC中搭建了混合双馈入直流输电系统的仿真模型,验证了该协调控制策略的有效性。

For the wide application of high voltage direct current(HVDC)transmission engineering,the continuous commutation failure of line commutated converter HVDC(LCC-HVDC)has a seriously negative impact on the stable operation of the power system.Therefore,in order to mitigate the continuous commutation failure of LCC-HVDC in hybrid multi-feed HVDC system,from the perspective of increasing the LCC-HVDC commutation voltage,a coordinated control strategy for hybrid multi-infeed HVDC systems is proposed in this paper.According to the real-time reactive power shortage of the conventional DC,the reactive power and active power of voltage source converter HVDC(VSC-HVDC)output are dynamically adjusted by this strategy,thereby changing the transient stable operating point of VSC-HVDC.Through the coordinated control of this strategy,the continuous commutation failure of LCC-HVDC is suppressed and the transmission capacity of the active power of the DC transmission system is greatly improved.Finally,a simulation model of the hybrid dual-infeed HVDC system is built in PSCAD/EMTDC,and the effectiveness of the coordinated control strategy is verified.