IEEE C37.45:2007 pdf free download

IEEE C37.45:2007 pdf free download.IEEE Standard Specifications for High-Voltage Distribution Class Enclosed Single-Pole Air Switches with Rated Voltages from 1 kV through 8.3 kV.
3. General rating information
3.1 Ratings
The ratings of distribution enclosed air switches shall he appiicaoic (or tnc service conditions spcciiiea in 3.1.1 of IEEE Std C37.40-20033. The ratings are validated as follows:
a) Rated maximum voltages, validated by the dielectric design tests specified in 4. I.
b) Rated continuous current, validated by the temperature-rise design tests at the rated continuous current specified in 4.4.
c) Rated lightning impulse withstand voltage [basic impulse insulation level (BIL)]. validated by the impulse withstand tests specified in 4.1.
d) Rated power frequency. as specified in 3.2.3.
e) Rated short-time currents, rated momentary withstand and rated 3 s withstand, validated by the design tests specified in 4.3.
1) The rated momentary short-time withstand current is the rms value of current, including the direct-current component that occurs in the first maximum offset current loop of the design tests specified in 4.3. The rated momentary current value for any device is based on its 3 s rated short-time withstand current multiplied by the appropriate asymmetry factor associated with the X’R specified. This rating provides an index of the ability of the device to withstand the electromagnetic forces that occur under maximum short-circuit conditions. To ensure that the device is tested with (he proper severity, the first and second major current peaks shall be equal to or greater than those specified in IEEE Std C37.4l .2000 Clause 10 for the rated momentary current of the device.
2) The rated 3 s short-time withstand current test provides an index of the ability of the device to withstand the heat that may be generated under long-time short-circuit conditions.
3) The two tests in item 1) and item 2) can be combined as described in IEEE Std C37.41-
2000. Clause 10.
It should be noted that for service conditions specified in 3.1.2 or 3.2 of IEEE Std C37.40-2003, additional testing to validate the rating of the device may be required.
3.2 Preferred ratings and performance requirements
3.2.1 Rated maximum voltage.