宁东直流近区新能源诱发次同步振荡风险评估

由于配套大容量的火电机组和装机容量较大的新能源发电并网机组,宁夏电网宁东直流近区存在诱发次同步振荡风险问题,本文分析和研究了宁夏电网宁东直流近区相关站点的PMU监测数据,对宁东直流近区因新能源发电诱发火电机组次同步振荡风险评估。结果表明:虽然间谐波引起次同步振荡的第一种作用形式,在新能源发电较小出力工况下,宁东直流近区火电机组发生次同步振荡的风险较低;但是,间谐波激发次同步振荡的第二种作用形式普遍存在,其对发电机轴系的危害甚至高于三相对地故障,因此,需进一步加强各种工况下次同步谐波与振荡的监测、研究及防范工作,以保障电网安全可靠运行。

Risk assessment on new energy induced sub-synchronous oscillation in eastern Ningxia DC nearby area of Ningxia power grid

Because of matching large capacity coal-fired units,and larger installed capacity of newenergy generating units in eastern Ningxia DC nearby area of Ningxia power grid,it exists the risk ofinducing sub -synchronous oscillation. by analyzing and studing the PMU (phasor measurementunit)monitoring data from related substations of eastern Ningxia DC nearby area,conducts riskassessment for new energy generation inducing sub-synchronous oscillation of coal-fired units ineastern Ningxia DC nearby area of Ningxia power grid. The result shows that:even though under thecondition of less output of new energy generation and the first efficient form of interharmonics causedsub-synchronous oscillation,appearing the risk of sub-synchronous oscillation is lower at coal-firedunits in eastern Ningxia DC nearby area of Ningxia power grid,but the second efficient form ofinterharmonics caused sub -synchronous oscillation is common existence,the perniciousness forshafting of generator is even higher than the three-phase ground fault,so should further strengthenthe monitoring,study and precaution for sub -synchronous harmonic and oscillation under variousoperating conditions,ensure power grid safe and reliable operation.