The Development Of Monitoring And Managing Subsystem For Large Scale Generator Protection Device

Due to the very high-capacity of the Generators in Three Gorges Hydropower Station, their running safety and stability have an important impact on the station or even the whole power system of China. The performance of protection plays a vital role for the safety of Generators. The protective devices for generators in the Three Gorges Left Bank Power Station are mainly manufactured by foreign companies. Though they have fairly well performances, there're still problems to be improved. Besides, many high-capacity power stations are planning to be built up in China, which need protection made in our own country. High requirements are showed up to the monitoring and managing subsystem of the protection, for its informatization and networking trend. So it is a study with high theoretical value and wide appliances to develop domestic large generator protection with high performances.In the beginning of this paper, the development history of generator protection has been reviewed, and the development of embedded system has been surveyed. Then a detailed explanation to the major designing principles and technical characteristic of the micro-computer based protection system of Three Gorges Hydropower Station is given, so as to its integrated configuration. According to the fault types of large-scale generators, the protective principles scheme is analyzed.The monitoring and managing subsystem is in charge of the entire protection and managing the human-machine interface. On the other hand, the subsystem is a bridge of communicating with outer terminal or integrated automation system. Referring to the application request of the device, this paper introduces the main scheme of the monitoring and managing subsystem based on embedded Linux operation system. Thanks to the real-time multi-task features of Linux, communication tasks via multiple ports, which are required by management system and integrated automation system, can be handled simultaneously. This paper explains the design princeples of function features of the main schme, and proposes solutions for problems encountered in the application of embedded Linux.Software design about monitoring and communication modules is one of the central works in this paper. The software is based on graphics user interface, which makes the software user-friendly. To increase development efficiency and function extendibility, modularized programming is adopted according to the different functions. The utility of configuration files makes the software more adaptable to different situations. The paper minutely describes the basic structure of the monitoring and managing software, the key techniques in the realization of graphics user interface and the programming of different modules.The monitoring and managing subsystem undertakes multiple ports, complex communication tasks. Referring the communication requirement, the communication infrastructure of the device is introduced. The communication system includes CAN-BUS, serial ports and Ethernet to meet the need of local and remote control and management. The paper describes the communication protocols, and their software realization.This protection for Three Gorges large scale generators has already passed the implement static and dynamic tests. The results showed that the general performance of this device has fully met the requirement of design. In these tests, the monitoring and managing subsystem completed its task successfully.