The Design Of Digital Protective Relay Test Set Based On The Digital Optical Electric Measurement

The development of non-conventional current or voltage transformers with digitaloutputs imposes a new digital interface between primary and secondary device. For thispurpose, a point-to-point link for device communication is defined in part 9-1 of the IECstandard 61850.The conversion of the sensor signals to the world of IEC61850-9-1 isperformed by Merging Unit. For the testing of protective relays, an digital protectiverelay test set output Ethernet frames according to IEC61850-9-1 is need to substitute themerging unit.By using the powerful Ethernet communication function of the embeddedARM(Advanced RISC Machines) and the fast digital processing ability of theDSP(Digital Signal Processor).The digital protective relay test set output the sampledvalues of voltage and current, which packing in the communication protocol defined inthe standard IEC61850-9-1,to realize the testing of the protective relay.The hardware of test set contains three parts: CPU, data processing units and digitalinput-output units;the software of it contains upper computer procedure, data processingand communication procedure and process test control, data compute procedure three parts.