The Design Of Digital Fault Recorder Based On SOPC

Fault recorder is the foundation of modern power system research, moreover, it is an important basis of evaluating the performance, analysising fault natures and causes for relay protection equipments. Fault recorder with excellent performance is of great importance to the power system safety and power quality.With the rapid development of power system, the conventional fault recorder that has a centralized structure began to show it's disadvantages, such as complexity of networking and configuration, difficulties to be integrated into the existing automation system, small allowance of redundancy, and it would be a disadvantage to system upgrades. At the same time,with the release and implementation of IEC61850, new technologies such as modern communication technologies,digital signal processing technologies, are beginning to be applied to the design of fault recorder to improve the performance of device and to reduce operating cost. Therefore, aiming to the lack of the traditional fault recorder and the demandation of IEC61850, this paper proposes a solution to new digital fault recorder based on SOPC, adopts FPGA, SOPC, DSP, Ethernet communication technology as technical support, realizes the reception of IEC 61850 sample value message and GOOSE message via fiber Ethernet and recording judgement based on Non-radix-2 FFT and CORDIC algorithm。This paper introduces the stament of the feature of SOPC technology and the requirements of digital fault recorder, and proposes a SOPC solution based on Altera FPGA and NIOS II processor. The design of hardware outside of the FPGA only needs clock, reset, power, memory and ethernet circuit.The design of hardware inside is divided into three modules; IEC61850 digital interface module, judge module and NIOSⅡprocessor. The IEC61850 digital interface module is responsible for receiving and decoding the sampling value message and GOOSE message.The judge module which is based on non-radix-2 FFT and CORDIC algorithm is responsible for realtime calculation of the data received,to ensure whether to start the recording. As the main controller, the NIOSⅡprocessor is responsible for coordinating each module, buffering the data received.and storing them in COMTRADE format. The function of NIOSⅡprocessor is realized by the combination of application program and HAL device drivers. Since the SOPC technology is adopted, the system can perfectly integrate the control logic, digital signal processing unit,32bit microprocessor into a single FPGA, and greatly simplifies the design work outside the FPGA, so allows the system to be upgraded conveniently. The system can receive and decode sample value message and GOOSE message based on IEC61850. then process a correct and rapid analysis. The recording file generated consistes with COMTRADE format, which can be shared with other equipments in the network. The research indicates that the system can record fault information of power system correctly and rapidly, providing a strong warranty for analysis of power accident and power safety.