IEEE C37.111-1991 pdf free.IEEE Standard Common Format for Transient Data Exchange (COMTRADE) for Power Systems.
IEEE C37.111 evolution and implementation of digital devices for fault and transient data recording and testing in theelectric utility industry has generated the need for a standard format for the exchange of such data for use with variousdevices to enhance and automate the analysis，testing, evaluation, and simulation of the power system and relatedprotection schemes during fault and disturbance conditions.
This standard defines a common format for the data files and exchange medium needed for the interchange of varioustypes of fault, test, or simulation data.
The proliferation and implementation of digital devices for the acquisition, analysis, simulation, and testing of power-system equipment has made available a profusion and variety of data that has not been readily available in the past.Since this data may come from a variety of sources, from different manufacturers using proprietary or other standardformats, a common format standard is necessary to facilitate the exchange of such data between devices with diverseapplications but that have the capability of utilizing digital data from other devices.
Analog tape recorders record analog signals on magnetic tape,usually using frequency-modulation techniques.Recorded tapescan be played back to drive oscilloscopes or plotters for visual examination of the recorded waveforms.Typical recorders monitor up to 32 analog signals.
By employing suitable hardware and software, the signals recorded on the analog tapes can be converted to digitalrecords in any desired format. The fidelity of the resultant output is dependent upon the limitations of both the analogrecorder and the digital-conversion system. The loss in fidelity can be minimized by a proper choice of the samplingsystem.
New relay designs using microprocessors are currently being developed and marketed. Some of these relays have theability to capture and store relay input signals in digital form and transmit this data to another device. In performingthis function, they are similar to digital fault recorders, except that the nature of the recorded data may be influencedby the needs of the relaying algorithm. As with the digital fault recorders, record format and other parameters have notbeen standardized.
Unlike the above devices that record actual power system events, transient simulation programs produce transient databy analyzing mathematical models of the power system. Because this analysis is carried out by a digital computer, theresults are inherently in digital form suitable for digital data dissemination.
While originally developed for the evaluation of transient overvoltages in power systems, these programs are findingincreasing usage in other types of studies, including test cases for digital relaying algorithms. Because of the ease withwhich the input conditions of the study can be changed, transient simulation programs can provide many different testcases for a relay.IEEE C37.111 pdf download.