4.Detailed analysis indicates that the transformer model based on the common information model (CIM) can easily consider the effect of tap changer regulation on the impedance of a transformer. It is a very satisfactory model for dispatching automation system, and the calculation of its parameters is very simple.
6.Combined with high-impedance techniques, the methods to determine the reactance capacity and transformer technical parameters of UHP electric arc furnace and the idea to determine the section of graphite electrode are presented in this paper.
7.For some difficulti es in the teaching of the relay protection such as impedance relay, high frequen cy protection, current protection and transformer protection, small interactive and dynamic application programs are compiled by Java (Java Applet), which are e mbedded in the web pages to make the students improve the learning efficiency.
8.Two phase equivalent circuit of Scott connection transformer is put forward. The impedance transformation relations between 3 phase and 2 phase are revealed,which are identical to the results obtained from the system coordinate transformation method.
9.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.
