电力系统保护与控制
電力繫統保護與控製
전력계통보호여공제
POWER SYSTM PROTECTION AND CONTROL
2014年
23期
31-37
,共7页
姜杰%许宏%陈贵文%张太勤
薑傑%許宏%陳貴文%張太勤
강걸%허굉%진귀문%장태근
鼠笼式感应电动机%状态方程%反馈电流%转速%配电网
鼠籠式感應電動機%狀態方程%反饋電流%轉速%配電網
서롱식감응전동궤%상태방정%반궤전류%전속%배전망
squirrel-cage rotor induction motor%equation of state%feedback current%speed%distribution network
大容量感应电动机会影响工业配网的短路电流水平,准确计算其反馈电流对系统保护配置及全网短路电流计算具有重要作用。电压跌落时电动机转速变化会影响电动机的反馈电流,不考虑转速变化可能会导致反馈电流计算结果不准确,影响保护的正确动作。利用感应电动机静态等值电路和复常系数线性微分方程组解法求解定转子磁链正负序强制分量和自由分量,进而得到电压跌落时计及转速变化的感应电动机反馈电流计算方法,并进一步探讨了转速对磁链和反馈电流各分量的影响。采用PSCAD/ EMTDC仿真软件中感应电动机的5阶动态模型仿真验证了该分析的正确性。
大容量感應電動機會影響工業配網的短路電流水平,準確計算其反饋電流對繫統保護配置及全網短路電流計算具有重要作用。電壓跌落時電動機轉速變化會影響電動機的反饋電流,不攷慮轉速變化可能會導緻反饋電流計算結果不準確,影響保護的正確動作。利用感應電動機靜態等值電路和複常繫數線性微分方程組解法求解定轉子磁鏈正負序彊製分量和自由分量,進而得到電壓跌落時計及轉速變化的感應電動機反饋電流計算方法,併進一步探討瞭轉速對磁鏈和反饋電流各分量的影響。採用PSCAD/ EMTDC倣真軟件中感應電動機的5階動態模型倣真驗證瞭該分析的正確性。
대용량감응전동궤회영향공업배망적단로전류수평,준학계산기반궤전류대계통보호배치급전망단로전류계산구유중요작용。전압질락시전동궤전속변화회영향전동궤적반궤전류,불고필전속변화가능회도치반궤전류계산결과불준학,영향보호적정학동작。이용감응전동궤정태등치전로화복상계수선성미분방정조해법구해정전자자련정부서강제분량화자유분량,진이득도전압질락시계급전속변화적감응전동궤반궤전류계산방법,병진일보탐토료전속대자련화반궤전류각분량적영향。채용PSCAD/ EMTDC방진연건중감응전동궤적5계동태모형방진험증료해분석적정학성。
Large capacity induction machines have a great influence on short-circuit current level of industrial distribution network. Accurate calculation of the feedback current plays an important role in protection configuration and short-circuit current calculation. The motor speed changing during voltage drop is an important factor affecting the accuracy of feedback current calculation, regardless of the speed changing may cause error in feedback current calculation and affect the operation of protection. Using the positive and negative sequence steady-state equivalent circuit of induction motor and constant complex coefficient linear differential equations solving process, forced component and free component of stator/rotor flux linkage are solved. Then the induction motor feedback current formula in consideration of speed changing factor is deduced. Furthermore, the influence of speed on each component of the flux and feedback current is analyzed. The correctness of the proposed analysis is verified by the fifth electromagnetic transient model of induction motor in PSCAD/EMTDC simulation software.