IEEE C37.111:1991 pdf download.IEEE Standard Common Format for Transient Data Exchange (COMTRADE) for Power Systems.
The rapid evolution and implementation of digital devices for fault and transient data recording and testing in the electric utility industry has generated the need for a standard format for the exchange of such data for use with various devices to enhance and automate the analysis, testing. evaluation, and simulation of the power system and related protection schemes during fault and disturbance conditions.
1.1 Purpose
This standard defines a common format for the data files and exchange medium needed for the interchange of various types of fault, test, or simulation data.
1.2 Need for a Common Format
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 standard formats, a common format standard is necessary to facilitate the exchange of such data between devices with diverse applications but that have the capability of utilizing digital data from other devices.
2. Sources of Transient Data
There are several possible sources of transient data for exchange.
2.1 Digital Fault Recorders
Digital fault recorders for monitoring power-system voltages. currents, and events are supplied by several manufacturers. These devices record analog signals by periodically sampling them and converting the measured signals to digital values. Typical recorders monitor 16—64 analog channels and a comparable number of event (contact status) inputs. Sampling rates, analog-to-digital converter resolution, record format, and other parameters have not been standardized.
2.2 Analog Tape Recorders
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 digital records in any desired format. The fidelity of the resultant output is dependent upon the limitations of both the analog recorder and the digital-conversion system. The loss in fidelity can he minimized by a proper choice of the sampling system.
2.3 Digital Protective Relays
New relay designs using microprocessois are currently being developed and marketed. Some of these relays have the ability to capture and store relay input signals in digital form and transmit this data to another device. In performing this function, they are similar to digital fault recorders, except that the nature of the recorded data may be influenced by the needs of the relaying algorithm. As with the digital fault recorders, record format and other parameters have not been standardized.IEEE C37.111 pdf download.