空分装置空压机同步电动机启动方式计算和分析

1、2006年第4期总第135期228000Nm3/h空分装置空压机同步电动机启动方式计算和分析228000Nm3/h空分装置空压机同步电动机启动方式计算和分析李志慧(天津钢铁有限公司设计部,300301摘要天钢228000Nm3/h空分装置空压机其驱动电动机为三相交流电动机,电动机启动方式有三种。通过计算和分析,确定了13500kW同步电动机采取电液变阻启动方式,10kV母线压降为90.6%,符合空分工艺要求并有不产生谐波、调试方便和易于维护等优点。关键词空压机电动机启动短路容量母线压降计算1概述天钢228000Nm3/h空分装置的空压机为德国MAN透平公司产品。其驱动电动机为ABB公司三相交流

2、同步电动机。电动机参数:Pe=13500kW Ue=10 000V Ie=882A Ne=1500r/min Mq/Me=0.96GD2= 10272N.m2。由于2x28000万Nm3/h空分设备计算负荷为58620kW,直接从1#总降站供10kV电压电源已经不能满足2x28000万Nm3/h空分设备用电要求和13500kW同步电动启动要求。因此需在氧气厂建35 kV变电所,专为228000Nm3/h空分设备供电。目前,电动机启动形式有三种:一是变频软启动;二是全压启动;三是降压启动。对于大容量变频软启动电气设备需要进口,费用很高,如13500kW电动机配套的变频软启动设备约2000万元左右

3、,而电气设备利用率又很低(每年13500kW同步电动机只启动一到二次,因此变频启动方式不可取。下面仅计算和分析全压启动和降压启动两种方式。对于特大型电动机很少采用自耦降压启动和串电抗降压启动方式,主要有三个原因;一是启动切换时,产生二次冲击电流;二是因为电气设备庞大,安装、运输困难;三是控制误差大不易调试、并且限制电动机单位时间内启动次数。电液变阻降压启动方式,是在电动机定子回路串接一特制可变液体电阻,启动过程中该电阻在电动机启动初始自动投入,利用液态电阻的热容量大及可恢复性良好等特性,通过PLC程序控制动极板的运动,按一定规律改变动定极板的间距,从而达到在预定启动时间内均匀无级减少液阻阻值,

4、并在阻值几近为零时切除,实现电动机转速均匀上升、平稳启动,达到控制电动机启动电流的目的。因此,本文仅就直接启动和电液变阻降压启动方式进行计算和分析。2全压启动计算2.1短路容量计算1#总降站35kV母线短路容量:最大Smax=620MVA,最小Smin=415MVA35kV电缆长度L=1km变压器容量Q=63000kVA变比35/10kVUk%=12计算电路和等值电路图见图1。图1(1基准容量Sj=100MVA基准电压Uj=10.5kV基准电流Ij=5.4986kA(2计算系统各元件标幺值最大方式35kV母线系统电抗:X*M=Sj/Smax=0.1613最小方式35kV母线系统电抗:X*m=S

5、j/Smin=0.24096电缆电抗:X*L=X2L2Sj/U D2=0.121100/372=0.0088变压器电抗:Pe=135000kW氧气厂35kV站35kV10kVBS m ax=620MVAS m in=415MVAL=1000mQ=63000kVAUk%=121#总降站35kVXsXLXb29X*b=Uk%/100Sj/Q=12/100100/63=0.19最大方式总电抗值:X*=0.1613+0.0088+0.19=0.360576最小方式总电抗值:X*m=0.24096+0.0088+0.19=0.43976最大方式I=Ij1/X*=15.249kASmax=1/X*MSj=

6、277.33MVA最小方式Im=Ij1/X*m=12.503kASmin=1/X*mSj=227.396MVA13500kW同步电动机10kV母线最大短路容量277.33MVA。最小短路容量227.396MVA。2.2全压启动计算KjqSe(Sd+Q fh母线允许85%电压时613.50.175(227.4+4.28(U*m=0.85=1/0.85-1=0.1758140.544母线允许70%电压时613.50.429(227.4+4.28(U*m=0.7=1/0.7-1=0.4298199.39式中:Kjq额定电压,电动机启动电流倍数。Se电动机额定容量,MVA。Q fh母线上负荷的无功功率

7、,Mvar。Sde供电系统短路容量,MVA。U*m母线允许电压标幺指。3串电液变阻启动仿真3.1仿真基本数据电动机额定电压:10kV电动机额定容量:13500kW电动机额定电流:882A电动机额定转速:1500r/min电动机堵转电流与额定电流比:设为3.28电动机额定电压下空载定子电流:0.2Ie=176A电动机额定电压下最大转矩与额定值比:1.67电动机全压启动时电磁转矩与额定值比:0.96电网额定电压:10.5kV转动惯量:10272N.m2仿真时间:50s电液箱电阻特性转折时刻:35s对应每一时刻电阻值:(2.6,1.8,0$电动机允许堵转时间:10s3.2计算结果电液最后温升度数:5

8、.699最大电流:1549A(约为1.8倍额定电流最大电网压降:990.166V(约为9.4%启动时间:27s电液变阻一次接线图见图2。图24结论4.1通过计算,13500kW同步电动机全压启动时,10 kV母线压降超过85%,达到70%以上。这在空分工艺上是不允许的,所以全压启动方式不可行。4.213500kW同步电动机采取电液变阻启动方式, 10kV母线压降90.6%,符合空分工艺。投资省(电液变阻成套电气设备约40万,并且有不产生谐波、调试方便和易于维护等优点。4.2我公司228000Nm3/h万空分装置的空压机同步电动机启动方式采取电液变阻启动方式是首选方式。(收稿2006-7-20责

9、编崔建华作者简介李志慧,男,1980年8月毕业于天津冶金工业学校自动化专业,工程师,现在天津钢铁有限公司设计部从事电气工程设计工作。10kV1DL2DL1QK RSABSTRACTSInnovation Creates the Landmark of Tianjin Iron&Steel IndustryReport of Tiangang Moving Eastwards ProjectDiscussion of Technique Problems for SWRH82B Steel in SmeltingWang YongranAbstract:By analyzing the tech

10、nique data of SWRH82B steel making at Tianjin Iron&Steel Co.Ltd,some improving measurements on how to realize the high carbon and low phos-phor of the smelting end and optimize the procedure for con-verter have been put out.Key words:smelting;converter;composition;dephosphor; techniquePractice of De

11、velopment of Grade N80Non-quenching& Tempering Casing Steel for ConverterGao Shurong Wang YongranAbstract:The technical characteristics and technological flow of grade N80non-quenching&tempering casing steel produced by Tianjin Iron&Steel Co.,Ltd are introduced.The practice shows the chemical compos

12、ition and mechanical prop-erty reach the standard and make the users satisfactory.Key words:converter;non-quenching&tempering steel; casing;refined melting;chemical composition;technique;devel-opmentPractice of Intensified Smelting of2000m3BF at Tian-gangSu QingjieKey words:BF;burden;blast volumn;bl

13、ast temperature;coal injection;practiceCause Analysis and Improving Measurement of Low Temperature Storage Flow during Common Carbon Steel for Billet and Round Billet Continuous CastingWang Baoming Wang Wenhui Zhang Yuhai Abstract:By analyzing the storage flow at the beginning pro-duction of the ste

14、el making plant of Tianjin Iron and Steel Co. Ltd,the temperature drop and influencing factors are found out and the improving measurement is put forth leading to reduc-tion of out-casting from low temperature storage flow and age flow;temperature drop;continuous casting heatsAnalysis and Treatment

15、of Synchronous Hydraulic up and down Troubles of Intermediate Tundish Carriage for Billet CasterCui YidongAbstract:The cause of synchronous hydraulic up and down troubles of intermediate tundish carriage for billet caster is an-alyzed.The trouble is found by means of exclusive method and the resolvi

16、ng method is put forward.Key words:caster;intermediate tundish carriage;hydraulic cylinder;hydraulic motor;over flow valve;troubleTrial Rolling of Hot-rolled65Mn Narrow Strip Steel Cui XiaohangKey words:rolling;narrow strip steel;spring steel;techno-logical flowDiscussion of the BF Keeper Tapping Ma

17、chine Modifica-tionZhang XiaomingAbstract:The cause of abnormal BF production pre-keeper tapping machine modification of2000m3BF at Tianjin Iron& Steel Co.Ltd is discussed.By modifying the rotating borer de-vice,pneumatic change valve,air tubes and aerial fog cooling system of drill rod,the trouble

18、rate of keeper tapping machine is greatly reduced and the good economic benefit gained.Key words:tapping machine;striking machine;impact power; rotating borer power;aerial fog cooling system;filteringAC-DC-AC Frequency Controlled Speed Regulating Sys-tem of Screwdown Motor of Plate Roughing Mill in

19、Tian-gang GroupYuan ShuningAbstract:The screwdown system of four-roll reversing roughing mill in Tiangang Group requires high control preci-sion,the speed control of screwdown motor is the key factor. The technological requirement and technical parameter of screwdown motor and AC-DC-AC frequency con

20、trolled speed regulating system are introduced.The system can meet the con-trol requirement of screwdown motor of roughing mill.Key words:roughing mill;screwdown device;motor;frequency controlled speed regulating system;vector control Calculation and Analysis of Starting Mode of Sychronous32006年第4期总

21、第135期Li ZhihuiAbstract:The drive motor of air compressor in228000 Nm3/h oxygenerator in Tiangang Group is three-phase AC motor with three starting modes.By calculating and analyzing,the starting mode of13500kW synchronous motor adopts electro-hydraulic rheostat and results in90.6percent of the volta

22、ge drop of10kV bus,that meets requirement of air seperation technology,and advantages,such as no harmonic wave and easy readjusting and maintaining.Key words:air compressor;motor;starting;short-circuit vol-ume;bus voltage drop;calculationAnalysis of Short-Circuit Accident of Transformer for 10kV BF

23、Converting StationChu AiqiuAbstract:In view of the three-phase short circuit accident resulted from mouse entering the transformer room,several rea-sons are analyzed.The short circuit current calculation shows the rated thermal stability current of former current mutual in-ductor is too small.Using

24、the new type current mutual inductor and enhancing the insulated protection of bus removes the trouble hidden and ensures the power running safety.Key words:tranformer;BF;short circuit current;heat effi-ciency;accident;analysisChecking and Calculating of Gear Intensity of Speed In-creasing Box for81

25、0DA3Air CompressorDai JunAbstract:According to the frequent oscillation of high-speed axle of speed increasing box,the gear strength is checked.The result shows that gear of speed increasing box can meet the re-quirement of contact strength and bend strength providing the reliable theoretic basis fo

26、r the removal of trouble hidden.Key words:air compressor;speed increasing box;gear; strength;checkingDiscussion on Application of the High Speed Steel Roll Ring and RollWei YixiangAbstract:The application of high speed steel roll ring in the High Speed Wire Rods Plant of Tiangang Group is introduced

27、. By comparison of merits and demerits of tungsten carbide roll ring with high speed steel one,the utilization possibility of high speed steel roll ring and roll in steel-rolling factories is put forth.Key words:mill;high speed steel;hard alloy;roll ring;rolling; applicationImplementation of Automat

28、ic Control Procedure for Full Fuel Industrial Steam BoilerYang ZhirongAbstract:Combined with the computerized control system of 14t/h boiler in Tianjin Iron&Steel Corporation,its working principle,the important control circuits and implementation methods for each control key are discussed.Key words:

29、industrial steam boiler;negative pressure of hearth;steam pressure;flux;frequency change control;computer matic Control System of Gas CleaningBing Jinwen Miao Zhijun Zhao YonggangAbstract:The structure of CITECT monitoring software and the realization of control functions of automatic control system

30、 of gas cleaning are introduced.After putting into operation,the system runs steadily with good effect.Key words:gas;cleaning;automatic control;monitoring soft-ware;functionStudy on Determination of Vanadium and Titanium Ele-ment in Vanadium Titano-magnetite with ICP-MES MethodYan Xuehui Zhang Qianl

31、inAbstract:The testing condition of vanadium and titanium ele-ment in vanadium titano-magnetite with ICP-MES method is studied during experiment.The sample is dissolved with the sealed high pressure resolution method and elements deter-mined by selecting the optimum analysis spectrum line and suitab

32、le apparatus.The result shows very small interference a-mong the co-existing elements and error less than2%to the standard and95%105%mark recovery rate.The method is rapid and simple with accurate analysis result.Key words:spectrograph;vanadium titano-magnetite;ele-ment;test;sample;analysis;studyProblems to Be Paid Attention in the Analysis of Suspen-sion of Metallurgical Waste WaterBian Lihuai Zhai RulingAbstract:The problems of representativity of water sample, constant weight of filter paper and absorption of salt in the analysis of suspension of metallurgical waste w