CAJ | 학술논문

撬棒(Crowbar)保护是否动作及动作时间会对双馈感应发电机(DFIG)短路电流特性产生影响。目前计及撬棒保护影响的相关研究均按照故障后撬棒保护瞬时动作来分析短路电流特性，但实际上机端电压跌落时，撬棒保护并非瞬时投入运行，而是根据故障严重程度带有不同的动作延时，这给短路电流的精确分析计算增加了难度。文中针对这一实际问题，以机端发生不对称故障为例，将故障电流分解为正向和反向同步旋转坐标系下的正序和负序分量，并根据撬棒保护动作时刻将故障过程分解为两个阶段，通过数学解析的方法给出整个故障过程的短路电流计算表达式。通过与MATLAB/Simulink 的 DFIG 标准模型对比，仿真验证了计算表达式的有效性，并分析了撬棒保护不同动作时间对DFIG短路电流特性的影响。
효봉(Crowbar)보호시부동작급동작시간회대쌍궤감응발전궤(DFIG)단로전류특성산생영향。목전계급효봉보호영향적상관연구균안조고장후효봉보호순시동작래분석단로전류특성，단실제상궤단전압질락시，효봉보호병비순시투입운행，이시근거고장엄중정도대유불동적동작연시，저급단로전류적정학분석계산증가료난도。문중침대저일실제문제，이궤단발생불대칭고장위례，장고장전류분해위정향화반향동보선전좌표계하적정서화부서분량，병근거효봉보호동작시각장고장과정분해위량개계단，통과수학해석적방법급출정개고장과정적단로전류계산표체식。통과여MATLAB/Simulink 적 DFIG 표준모형대비，방진험증료계산표체식적유효성，병분석료효봉보호불동동작시간대DFIG단로전류특성적영향。
The activation of Crowbar protection and its action time both have impacts on the short-circuit current characteristics of doubly fed induction generator(DFIG).Nowadays,most studies assume the instantaneous activation of Crowbar protection after the occurrence of voltage sag.However,in practice,the Crowbar protection acts with different time delay depending on the severity of the voltage sag,which complicates the precise calculation of the short-circuit current.Aiming at this practical problem,this paper takes asymmetrical fault occurred at the stator terminal as an example.The fault current is divided into positive and negative sequence component in the forward and reverse synchronous rotating reference frame respectively,and the fault process is divided into two stages according to the Crowbar insertion moment.The formula of the fault currents during the fault process is derived in detail,and compared with the standard DFIG simulation model provided by MATLAB/Simulink. The comparison results validate the proposed formula and the effect of insertion time on DFIG short-circuit current characteristics.