( 4 ) based on system identification , the hardware - software system of traction transformer is designed in this paper , in which hardware structure of protection unit and action - criterion of protection are exploringly studied （ 4 ）初步设计了基于该原理的牵引变压器保护的软硬件系统，着重对保护单元的硬件构成及保护动作判据进行了分析讨论。
In view of this fact , a novel method based on identification of winding parameter is presented , which need not to distinguish magnetizing inrush . simulation results by using emtp and matlab demonstrate the feasibility and availability 该方法能有效的区分牵引变压器内部故障与外部故障、励磁涌流等情况，用emtp及matlab进行仿真计算，验证了该方法的可行性和有效性。
Two kinds of new on - line monitoring methods , which are based on measuring primary , secondary currents and voltages to calculate the short - circuit reactances of windings for detecting the deformation windings of power transformer , are proposed in the paper . the methods used for on - line measuring the short - circuit reactances of traction transformer in electric railways , are designed 本文提出了两种在线监测变压器绕组变形的方法，通过在线监测变压器绕组原、次边的电压和电流量，实时计算变压器绕组的短路电抗来判断变压器绕组变形情况，并对电气化铁路主要接线型式的牵引变压器绕组变形的在线监测方案进行了设计。
Impedance - matching balanced traction transformers ( balanced transformers in this paper for short ) are step - down transformers , they transfer symmetrical three phase voltage in primary side to perpendicular two phase voltage in secondary side . they are different from any other transformers , so their short - circuit current analysis and short - circuit test method must be taken into special account 阻抗匹配平衡牵引变压器(本文中简称平衡变压器)是一种将一次侧三相对称电压变换为二次侧二相垂直电压的降压变压器，它不同于已有的任何一种变压器，短路电流的分析计算和短路试验必须予以重新研究。
At present , differential protection is often used as the main protection for traction transformers . however , the existing of certain factors , such as magnetizing inrush , over - excitation , ct saturation and mismatching of ct ratio , will result in that it is hard to distinguish state current and fault current , and differential protection misoperation or maloperation , then secure operation of electric railways system will be threatened 目前，牵引变压器通常采用差动保护作为主保护，但是在某些因数的影响下差动保护并不能准确的区分牵引变压器内部故障或非内部故障，如故障电流与变压器处于励磁涌流、过励磁， ct饱和及ct变比不匹配等情况下的状态电流就很难准确的区分，可能造成保护误动或拒动，从而危及整个铁道电气化系统的安全运行。
The main achievements of the thesis are as follows : ( 1 ) kinds of techniques to detect magnetizing inrush of traction transformers are thoroughly investigated in this paper , and their limitation are indicated and corresponding improvement techniques are proposed . ( 2 ) in this paper , flux linkage equilibriun equations are used to build " ash - box " models of some traction transformers based on system identification , such as two - winding single - phase traction transformer , impedance - matching equilibriun traction transformer and scott traction transformer 论文的主要内容有： （ 1 ）详尽分析了现有的针对牵引变压器励磁涌流算法的保护算法，提出了每种算法的局限性及其改进方法； （ 2 ）提出适用于铁道电气化系统中各种牵引变压器对应的三?二相转换规则，利用该规则可将对应量的转换置于保护软件中，从而可大大减轻在牵引变压器两端外部复杂的接线。
Because the harmonics in tangyin substation are primarily from electric traction loads , this paper gives the structures of several main locomotive models and general harmonics they produce . the harmonics produced by electric locomotive have a characteristic that their range and phase are both dispersive . this paper also analyzes the impedance - matching balance transformer ' s structure and harmonics injected into the power system at its primary side , and sums up the characteristics of the harmonics from electric traction loads in the tangyin traction substation 鉴于汤阴变电站的谐波主要来自电力牵引负荷，本文列举了电力机车几种主要车型的结构以及它们产生谐波的概况，得出了电力机车的各次谐波电流幅值和相角具有较大分散性的特点。针对汤阴牵引变电站的牵引变压器，分析了阻抗匹配平衡变压器的结构及其高压侧注入电网的谐波，推导了有关计算公式。通过理论分析并结合汤牵线的实测谐波数据，归纳了电力牵引负荷注入汤阴变电站的谐波的特点。
In accordance with the driving characteristics of ac driving locomotive , the working status of its traction transformer is analysed . the questions that should be considered in the traction transformer design of ac driving locomotive are mentioned . these questions are the large short - circuit impedance of traction winding , higher harmonic current , over - excitation and dc magnetization caused by large variation of the network voltage , etc . some disposal methods are given 针对交流传动电力机车的传动特点，对其中的牵引变压器的工作状态进行了分析，指出交流传动电力机车用牵引变压器设计时需考虑的牵引绕组的短路阻抗大、电流的高次谐波、网压波动大可能引起的过励磁以及直流磁化等问题，同时给出了相应的一些解决方法。
In the models , the iron core nonlinearly of the traction transformer and the magnetic hysteresis effect without the b - h curve are considered . having tested by digital simulation , the winding parameter has not changed in the state of external fault or magnetizing inrush etc . but the winding parameter has obviously changed in state of inter fault or inter - turn fault . ( 3 ) the rules three phases converted to two phases of traction transformer in electric railways are developed in this paper （ 3 ）利用牵引变压器磁链平衡方程，建立了基于系统辨识理论的双绕组单相接线牵引变压器、阻抗匹配平衡牵引变压器及scott （斯科特）接线牵引变压器的“灰箱”模型，该模型考虑了牵引变压器铁芯非线性和磁滞效应，但又不直接反映在模型中，并且无需铁芯的b - h曲线数据。
