导　　师： 夏成军

学科专业： 080802

授予学位： 硕士

作　　者： ;

机构地区： 华南理工大学

摘　　要： 大型电力变压器作为电力系统中的关键设备之一，必须保证其运行的可靠性，因此需为其配置备用变压器。理想的备用变与主变型号一致，各方面的参数均相同，这样在主变发生故障时备用变能及时投入，保证系统能够正常运行，避免因停电对整个电网造成巨大损失。目前主变备用机制仅考虑了N-1，当主变处于维修中而备用变又在运行中发生故障时将导致失去备用，这时用其它变压器作为临时备用就显得很有必要。由于用于替换的变压器可能与被替换变压器非同一型号，三相参数有一定的偏差，为此迫切需要建立主变单相替换仿真模型来研究其三相参数不对称情况及其适应性问题。 本文结合500kV罗洞变电站#2主变单相替换工程实例，运用PSCAD//EMTDC电磁暂态仿真软件对主变单相替换后，因三相参数不对称情况及其适应性问题进行研究和分析，具体的研究内容包括： 在PSCAD//EMTDC提供的经典模型和UMEC模型中选择适合本次研究的变压器模型，运用变压器模型建立既有磁又有“电”直接联系的三绕组自耦变压器，考虑了绕组间以及绕组对地电容参数，将三相三绕组自耦变压器通过一定的连接形成主变单相替换模型。 研究了主变单相替换后因三相短路电压百分比不对称对绕组的损耗特性影响，并从电压水平、负载率以及分接头档位三个方面研究了三相参数不对称对三相不平衡度的影响。 通过对变压器中压侧出线端各种故障类型的仿真与分析，研究了三相参数不对称对故障暂态电流的影响，重点讨论了三相参数不对称对变压器励磁涌流的影响，并通过对正常情况以及故障情况下的仿真与分析，研究了三相参数不对称对变压器差动保护、过流保护以及零序电流保护的影响。 根据500kV罗洞变电站#2主变单相替换工程替换后，35kV Large power transformer as one of the key equipment in the power system must ensurethe reliability of its ope ration，and therefore need the standb y transformer. The model of idealstandby transformer and the main transformer is consistent with all aspects of the sameparameters，so the standb y transformer can be timely put into operation to ens ure the systemin nor mal condition when the main transformer fails，avoid causing huge losses due to poweroutage on the entire grid. Transformer backup mechanism only considers the N-1，whenmaintenance of the main transformer and failure of standby transformer will result in loss ofstandb y transformer. Then using another transformer temporarily as backup becomesnecessary，the temporary transformer may not have the same type with the main transformerand the three-phase parameters have a certain bias，this is a urgent need to establish thesimulation model of transformer single phase replacement to study the problem of unbalancedthree-phase and adaptability. This thesis according to the single phase replacement project of#2transformer in500kVLuodo ng substation， us ing the PSCAD//EMTDC to study the unba lanced three-phaseparameters problem and adaptability after the main transformer single phase replacement，theconcrete research contents including： Selecting the suitable transformer model for this study between classical model andUMEC mode l in PSCAD//EMTDC，and then using the transformer mode l establish the threewinding a utotransformer which has both magnetic contact and directly power contact，at lastthe single phase replacement model of main transformer is established by three-phase threewinding autotransformer through a certain connection. The impact on loss characteristic of winding and harmonic due to the asymmetry ofthree-phase short-circuit voltage percentage after single phase replacement is studied，andthe n the influe nce of three-phase parameters asymmetry on three-phase unbalance factor isresearched from three aspects of the voltage

关 键 词： 主变 三相参数不对称 单相替换 建模仿真 适应性

领　　域： [电气工程]