BS EN 60255-24 pdf free download

BS EN 60255-24 pdf free download.Electrical relays — Part 24: Common format for transient data exchange (COMTRADE) for power systems.
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. Any data which is necessary for the reproduction of the sample data is termed critical. If such data is missing, the file may be unusable. 2.3 primary/secondary ratios the devices used to measure and record events on a high voltage system are not capable of directly accepting the high voltage and high currents of the power system. These devices are built to accept inputs in more manageable and less dangerous levels, termed secondary quantities. Voltage transformers and current transformers are used to reduce the voltage and current signals on the power system to these lower values. The transformer ratios are chosen so that when the power system is running at the rated or nominal primary value, the secondary value is at the nominal secondary value. The ratio is specified in primary:secondary order, the convention being that the primary is closest to the source of power. Primary ratings are available for all common voltages and load values on the power system. Common values for the secondary values are in the region of 70 V line-to-ground, and 1 A or 5 A. An ANSI/IEEE standard [1 2] 1) specifies the description and rating of these transformers. Thus for a current transformer applied to a feeder and rated at 800:5, the secondary current will be at the nominal 5 A value only when the primary load current was 800 A. Lower load values result in correspondingly lower values of secondary current. For three-phase applications, voltage transformers are normally rated in phase-to-phase voltage values rather than phase-to-ground. The output of a voltage transformer rated at 345 kV: 1 20 V will be 1 20 V phase-to-phase (70 V phase-to-ground) only when the primary system phase-to-phase voltage runs at 345 kV. The term “line-to-line” is used interchangeably with the term “phase-to-phase”, and similarly the term “line-to-ground” is used instead of “phase-to-ground”. 2.4 floating point notation real numbers may be stored in several ways. Numbers of a limited range can be entered as a numeric string with a decimal point. For larger or smaller numbers, any reasonable limit on string length leads to a loss of resolution. In such cases it is desirable to store the number in a format allowing use of a representation of the significant digits (mantissa) and a multiplier (exponent) format. Spreadsheets and other mathematical programs often use a floating point notation to represent such numbers. BS EN 60255-24  pdf download.