Research And Application On A New Type Transformer Protection And Its Ethernet Communication

Power transformers are essential and important elements of power systems, and the reliability of power transformers directly determines whether the power system works safely or not. This dissertation gives a special research in microcomputer relay protection for power transformer of 110kV or below voltage ratings, which based on widely summarizing the theory of power system relay protection and its advanced trend. After analyzing the working character of the transformer in details and absorbing the advantages in other power transformer protection, a scheme which is fit to power transformer of 110kV or below voltage ratings is put forward. The scheme optimizes the configuring principle of transformer protection. According to this scheme, a design platform of power transformer protection device is also advanced, which is based on high capability digital signal processing chip (DSP) and high accurate AD sampling chip. On the ways of hardware design, complex program logic device (CPLD) is applied to take place of traditional logic chip; and communicate with long-distance computer by Ethernets. Which buildup the function of communication of the so this device can meet the demand of Automatic control on power system. On the ways of software design, the application of the Fourier algorithm advances the computer accuracy, and the driver program of RTL8019AS chip and embedded tidy TCP/IP protocol stack are implemented. The device that combines measurement with protection and network shows the modern design concept. Which fill with the need of intelligence and information of device of transformer protect, and provide foundation for the seamless communication of the power station automation system. The experiment results show that this device has accurate measuring, fast, correct response, and the feature qualifies the requirements.