IEEE C5717-2012 pdf free

IEEE C5717-2012 pdf free.IEEE Standard Requirements for Arc Furnace Transformers.
When water-cooled, the temperature of the cooling water (ambient temperature) shall not exceed 30 O(, and the average temperature of the cooling water for any 24-h period shall not exceed 25 °C. Minimum water temperature shall not be lower than I O unless the cooling water includcs antifreeze suitable for 20 °C operation.
4.1.2 Cooling air temperature limit
When air-cooled, the temperature of the cooling air (ambient temperature) shall not exceed 40 0c’ and the average temperature of the cooling air for any 24-h period shall not exceed 30 °C.
4.1.3 Operating temperature conditions
If the operating temperature conditions of a furnace transformer at the intended installation site do not fall within the limits of normal service conditions” as stated in 4.1 .1 or 4.1.2 and the latest revision of IEEE Std (‘57.12.00. then the operational limits of the transformer temperature rise should be modified accordingly within an acceptable 10 ( temperature range.
In such cases, the specified temperature rise of the transformer shall be reduced by the same amount as thc overload of the cooling mediums mean temperature (i.e. if the water cooling temperature increases from 30 0C to 40 “C, then the transformer temperature rises must be decreased by the same 10 “C’).
Alternately If the user intends to operate the transformer with an increased cooling medium mean temperature (e.g. for water from 30 O( to 40 O(), while maintaining the temperature rise limits, then the transformer rated power must to be reduced according to Table 1.
Failure to comply with the requirements of 4.1.3 while operating the transformer at full capacity may cause an elevated cooling medium temperature resulting in accelerated ageing of the transformer insulation system. The rate of insulation aging may be determined from Table 1 of the latest revision of IEEE Std C57.91.
4.1.4 Altitude
The altitude shall not exceed 1000 m (3300 fi). If the altitude should exceed 1000 m (3300 ft) then correction factors per IEEE C57.12.00-2000 Section 4.3.2.1 Table I will apply.
4.1.5 Supply voltage
The supply voltage wave shape shall be approximately sinusoidal and the phase voltages supplying a polyphase transformer shall be approximately equal in magnitude and time displacement.
4.1.6 Maximum continuous transformer operating voltage
The maximum continuous transformer Operating voltage should not exceed the levels specified in ANSI C84. 1-1995. System conditions may require voltage transformation ratios involving tap voltages higher than the maximum system voltage for regulation purposes. However, the appropriate maximum system voltage should be observed under operating conditions.IEEE C5717 pdf free download.