基于行波功率S变换能量JS散度的直流换流器站间保护方案研究

Research on the Inter Station Protection Scheme of the DC Converter Based on Traveling Wave Power S-Transform Energy JS Divergence

以水电、光伏、风电为主的可再生能源占比快速增加,直流输电技术成为解决新能源消纳的主要工具。直流换流器站间线路较长,严苛故障情况及通讯干扰可能导致现有双端保护方案的失效,进而导致换流器闭锁问题。为解决该问题,提出了一种基于Jensen-Shannon(JS)散度的双端保护方案。首先,建立柔性直流系统模型,提出行波功率的定义并推导其表达式;随后,基于该表达式分析行波功率幅频特性,并据此提出一种JS散度表达功率故障特性的方案;最后,依据仿真模型设置不同故障工况验证了该方案的性能,结果表明,该方案不受分布电容的影响。

Due to a rapid increase of the proportion of renewable energy based on hydropower,photovoltaic and wind power,the direct current(DC)transmission technology has become the main tool for solving new energy consumption.As the lines between DC converter stations are long,severe fault conditions and communication interference may lead to the failure of the existing double-ended protection scheme,which in turn leads to the converter blocking.To solve this problem,a double-ended protection scheme based on Jensen-Shannon(JS)divergence is proposed in this paper.Firstly,a flexible DC system model is established,the definition of traveling wave power is proposed and its expression is derived;secondly,based on the expression,the amplitude-frequency characteristics of traveling wave power are analyzed,and a scheme of JS divergence to express power fault characteristics is proposed accordingly.Finally,according to the simulation model,different fault conditions are set to verify the performance of the scheme.The simulation results show that the scheme is not affected by distributed capacitance.