Research On The Application Of An Intelligent Bus In Relay

Relay protection equipment and automatic device are widely used in power plants and substations. Now, there is not a uniform platform for the relay protection device. With the power system user's continuous improvement to the device's maneuverability, we need to design a unified platform for relay protection device. Because the relay protection devices of power plants are used in different voltage and they have different complexity, we should design a platform which can realize flexible configuration. And with the research of the digitization, the use of electronic transformers and optical transformers, the access to the IEC61850 protocol, the data information that used in the protection device is increasing rapidly, the relay protection device should transform a large amount of data and in high speed, therefore, it is necessary to develop a high-speed intelligent internal data bus.In this paper we analyze and compare several kinds of internal bus. Through these analyses we can conclude that these internal buses can't be adapted to the requirements of the application of relay protection device. Then, we analysis the characteristics of LVDS. LVDS (voltage differential signaling low), which is a low voltage differential signal technology, is a high-speed transmission technology, which provides a voltage swing very low (350 mV) of high-speed differential signal, can achieve rapid data transmission, and power consumption is reduced. Its highest data rate can run up to 3.125 Gbps, is an ideal bus for data transmission. However, for the high speed, multi point and variable load demand of relay protection device, the original LVDS level is not competent for device's requirement, and its extension level BLVDS will drive current to 10-12mA, which means that the driving load can reach 30 ohm, and has low noise and support business card hot swap function. Therefore, BLVDS is an ideal choice for relay protection device system. Through the above analysis, this paper finally determines to use the BLVDS for the relay protection device's internal bus.Then this paper designs the hardware which based on BLVDS intelligent bus, selects the appropriate FPGA chip to build BLVDS bus, and designs the various functional modules on the bus, including CPU, AC, DI, DO, etc.. Then this paper designs the software to complete their respective functions.After the completion of the platform, this paper designs the automatic quasi synchronization device based on the platform to verify the feasibility of the platform. Automatic quasi synchronization device is an automatic device for electric power system, which has very important affect in power plants. The quasi synchronization device's synchronization point should be configured neatly and its requirements for data in and out configure are complex, so this can verify the design well.Finally, this paper tests and verifies the automatic quasi synchronization device by the electromagnetic compatibility and routine experiments. Finally this paper summarizes the subject for further research.