Research And Development Of OCT Interface Based On IEC61850

Electronic transformer, fibre-optic communication technology and computer technology constitute the fibre-optic local area network, which applies into the power system, is the developing direction of electric substation automation technology. To be the first communication standard system aimed to realize the inter-performance among the intellect electron devices of electric substation automation system, according to the monitoring, controlling and relay protection three functions that electric substation automation system must be achieved, IEC61850 divides the system into three layers logically, they are electric substation layer, bay layer and process layer. As the interface of bay layer and process layer, merging unit is used to connect the digital output of electronic transformer and protection, measurement and controlling devices.This paper has studied and compared the digital interface merging unit(MU) correlative standards of IEC60044-7/8, IEC61850-9-1 and IEC61850-9-2, and has pointed out that it has the practical meaning to realize the interface between the optical current transformer and secondary devices based on IEC61850-9-1.The merging unit collects the data of 12 roads and transfers to secondary equipment according to IEC61850-9-1. This paper divides the merging unit into three modules: synchronizing function module, data collection and deal function module and Ethernet transmission function module. Since merging unit has the features of multi-dealing-task at the meantime and better real-time character, this paper has designed the scheme which adopts FPGA and Ethernet controller CS8900A to make up of merging unit.The synchronizing function module submits the synchronic switching signal to each A/D converter once it has rightly identified the synchronic second pulse-timing signal from the GPS receiver.After submitting the synchronic signal to each A/D converter, the data collection and deal function module receives the output data from the multi-channels and checks their validity, and then encodes them following IEC61850-9-1.The Ethernet transmission function module drives the Ethernet controller CS8900A with FPGA and the Ethernet protocol is completed automatically by CS8900A itself.After completing the system-design of each module, the author workout the program and then simulink, at last executes the prototype board to test and verify.This paper is one part of the optical current transformer (OCT) research, it has the strong engineering practical background. To study and design the interface of optical current transformer can accelerate the development of optical current transformer into practice and products.