IEC 60255-24:2001 pdf free download

IEC 60255-24:2001 pdf free download Electrical relays — Part 24: Common format for transient data exchange (COMTRADE) for power systems
1 Scope and object This part of IEC 60255 defines a format for files containing transient waveform and event data collected from power systems or power system models. This standard applies to files stored on physical media such as digital hard drives and diskettes.
It is not a standard for transferring data files over communication networks. The format is intended to provide an easily interpretable format for use in exchanging data; as such, it does not make use of the economies available from data encoding and compression which proprietary formats depend on for competitive advantage.
2 Definitions For the purpose of this part of IEC 60255, the following definitions apply.
2.1 data representations data stored in files as a series of binary bits NOTE Each bit can be either a 1 or a 0. The bits are organized in groups of 8 bits called bytes. When a computer reads the data in a file, it reads the data as a series of bytes.
2.1 .1 binary data data organized in the form of bytes NOTE The 8 bits in a byte can be organized in 256 different combinations. They can be used, therefore, to represent the numbers from 0 to 255. If larger numbers are needed, several bytes can be used to represent a single number, e.g., 2 bytes (1 6 bits) can represent the numbers from 0 to 65535. When the bytes are interpreted in this fashion, they are known as binary data. Several different formats are in common use for storage of numeric data in binary form.
2.1 .2 ASCII (American National Standard Code for Information Interchange) data symbols that match 1 27 of the combinations of eight binary bits
NOTE As an alternative to a byte representing the numbers 0 to 255, it can be used to represent 255 different symbols. The American National Standard Code for Information Interchange (ASCII) is a standard that lists symbols that match 1 27 of the combinations of eight binary bits, e.g. the byte 01 000001 represents an upper case “A” while 01 1 00001 represents a lower case “a”. With 1 27 different combinations, it is possible to represent all of the keys on the keyboard plus many other special symbols. The remainder of the 256 combinations available from an 8-bit format are used for drawing and other special application characters. To represent a number in ASCII format requires one byte for each digit of the number.
2.2 critical/non-critical
some of the data in the configuration file is not absolutely necessary for the reproduction of the sample data, and some variables provided for in the configuration file may not be relevant to a particular application. Such data may be described as non-critical and may be omitted. An example of such non-critical data is the recording device channel name. However, the position normally occupied by such variables must be maintained in order to maintain the integrity of the file. If data is described as non-critical in any section of the standard, the position may be left empty or filled, using the space character, and the corresponding data separator following the preceding data separator applied with no intervening characters or spaces.