Study on new type of IED with integrated functions in intelligent substation

Intelligent substation is the most important aspect of Smart Grid constructing. There are many problems during intelligent reconstruction of conventional substation, one of which is to add a variety of secondary equipments. To address this problem, the paper puts forward two distributed configuration schemes of secondary devices using the IED with integrated functions of process level and bay level in intelligent substation. Compared with the normal configuration scheme, the distributed schemes bring a significant reduction of IED. Based on the new schemes, the authors design a new type of integrated IED, which completely realizes merging-unit, intelligent-terminal, measurement-control and protection functions. The integrated IED is composed of four dominating parts: Main Processor Model, Data Processing Model, FPGA Integrated Model and Intelligent Control Model. The IED can receive sampled values from electronic transformers and Ethernet frames following IEC 61850-9-2 from other merging units. The information model of the integrated IED is established according to IEC 61850 standard. In conclusion, the integrated IED is especially suit for intelligent reconstruction of lower voltage substation with the characteristic of reasonable design, superior performance and cost effective.