The Process Level Simulation Design Of Digital Transformer Substation Based On IEC 61850

Transformer substation is an important link of the power transmission and distribution system. Since the application of early RTU and high frequency protective equipments, the transformer substation has been provided with digital characteristics. Furthermore, the publication of IEC 61850 standard has pointed out the direction for the development of digital transformer substation. In recent years, the digital transformer substation has become a hotspot of the industry for its unique advantages in construction, operation, maintenance, management and other aspects. During the development process of IEC 61850 based equipments, the transient voltage and current signals have to be detected in order to check the reliability and sensitivity of the equipment. Therefore, the present thesis proposes to utilize Matlab to realize the simulation of process level equipment in accordance with the IEC 61850 standard, and simulation data is used as a flexible, convenient and economical experimental tool to test the bay Level equipment.This thesis first briefly introduces the main content of IEC 61850 and analyses its core idea in detail. Aiming at power line protection and measurement application, a specific construction approach of sampled value model is proposed. Based on a further study of sampled value model, concrete collocation is conducted to the logical device and the logical nodes within the sampled value model, which provides good theoretical foundation for the realization of sampled value simulation.Merging unit is the interface module of electronic transformer and bay level equipment, which mainly synchronously collects the digital information output by three-phase voltage and current, and gathers the digital information to a secondary protection in a certain format. The thesis suggests the simulation of the data processing module of the merging unit based on S-function, and completes the simulation design of the process level of digital transformer substation by utilizing a Matlab/Simulink module. By comparing the system data under rated state, 20% rated current, 5% rated current and typical fault state, and the data output by the merging unit, it can be seen that the simulation error output by the merging unit can satisfy the error limit of a transformer, so the simulation data is accurate and effective, and effective signals can be provided for bay level equipment testing.The process level communication has strong real-time characteristic. TCP and UDP are the most important protocols on the transport layer of a TCP/IP model. Although UDP is connectionless-oriented, it has better transmission efficiency than TCP and can satisfy the IEC 61850 based "Request/No response" service requirement. The thesis realizes a socket program project which adopts a connectionless-oriented protocol on the transport layer, and the project also has compatibility for communication based on IEC 61850-9-2.Certain process level equipments for special purposes still keep analog output interface. Therefore, analog output interface should be kept during the realization of process level network communication. This thesis proposes to use high-speed high-performance analog output acquisition card PXI-2502 to realize the analog output of process level. In order to verify the precision of analog output, simulated values are collected to a pc computer again by a high-performance input acquisition card PXI-2501, and by comparing the analog output data and the simulation data, the analog output is proved to be accurate and reliable.