北华大学毕业设计（论文）--摘要随着科技的不断进步与发展，用户对电能质量的要求越来越高，而电压偏移的大小直接影响电能的质量。在电力系统中，变电站占有重要地位，因为电力系统中很多操作运行是在变电站内完成，所以选取合理地电压无功控制策略对变电站的稳定运行是非常必要的。本文就目前变电站常用的调节有载变压器的分接头与投切补偿电容器的方法做了简介，并设计了基本的控制方案。首先简单的介绍了基于九区图控制策略的变电站电压无功综合控制设计以及有关于九区图控制策略的不足之处，为了改善其不足之处本文提出通过增加两个防振小区的改进九区图控制策略，与传统九区图控制策略相比而言，前者等待运行点出防振小区，虽然牺牲了无功指标却保证了电压质量的合格，而且避免产生震荡的动作现象。变电站电压无功综合控制器以有很强的抗干扰能力，易于与工业系统连成一个整体、易于扩充其功能的S7-300PLC作为主控单元，根据开关量采集电路和模拟量采集电路获取所需参数进行电压无功控制。为了提高控制可靠性，需要硬件控制与软件控制相结合，于此本文编制了相应的软件控制流程图。关键词：变电站；电压；无功功率；九区图控制策略；可编程控制器AbstractWiththecontinuousadvancementanddevelopmentoftechnologyuserrequirementsforpowerqualityandhigher,andthevoltageoffsetdirecteffectonthequalityofelectricity.Inthepowersystem,thesubstationoccupiesanimportantposition,becausemanyofthepowersystemoperationandrunningiscompletedwithinthesubstation,itisnecessarytochooseareasonablevoltageandreactivepowercontrolstrategyforstableoperationofthesubstation.Inthispaper,commonlyusedsubstationtransformerloadtapandcompensationcapacitorswitchingmethodofadjustingtodoabriefintroduction,anddesignsthebasiccontrolscheme.First,abriefintroductionontheNinthRegionPlotcontrolofvoltageandreactivepowerintegratedcontrolstrategydesign,andataboutnine-zonediagramcontrolpolicyshortcomings.Inordertoimproveitsshortcomingsbyaddingtwovibration-proofpaperspresentsanimprovedcellnine-zonediagramcontrolstrategy.Withthetraditionalnine-zonediagramcontrolstrategycompared,theformerwaitingtorunpointouttheanti-vibrationarea,althoughattheexpenseofreactiveindicatorswastoensurethatthequalifiedvoltagequality,andavoidthephenomenonofshockaction.VoltageandReactivePowerIntegratedcontrollerhasastronganti-jammingcapability,easywithindustrialsystemsasawhole,toexpanditscapabilitiesS7-300PLCasthemasterunit,accordingtodigitalacquisitioncircuitsandanalogacquisitioncircuitacquirestheparametersrequiredvoltageandreactivepowercontrol.Inordertoimprovecontrolreliability,requireshardwarecontrolandsoftwarecontrolcombination,thisarticledevelopedacorrespondingsoftwarecontrolflowchar