IEEE C57.17-2012 pdf free
IEEE C57.17-2012 pdf free.IEEE Standard Requirements for Arc Furnace Transformers.
Whcn water-cooled. thc tcmperaturc of thc cooling watcr (ambient temperature) shall not cxceed 30 O(, and the averagc temperature of the cooling water for any 24-h period shall not exceed 25 °C. Minimum water temperature shall not be lower than I °C. unless the cooling water includes 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 °c and the average temperature of the cooling air for any 24-h period shall not exceed 30 °C.
4.1.3 Operating temperature conditions
lithe 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 C57.12.0O, then the operational limits of the transformer temperature rise should be modified accordingly within an acceptable 10°C temperature range.
In such cases, the specified temperature rise of the transformer shall be reduced by the same amount as the overload of the cooling mediums mean temperature (i.e. if the water cooling temperature increases from 30 °C 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 °C to 40 °C), 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 clevated 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 excccd 1000 m (3300 fl). If the altitude should exceed 1000 m (3300 II) 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 CX4.l-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.
4.1.7 Indoor operation
Unless otherwise specified, transformers shall he suitable for indoor operation.
4.1.8 Step-down operation
Furnace transformers shall be designed for step-down operation.
4.2 Transformer kVA ratings
Kilovolt-ampere ratings shall he as shown in Column I of Table 2. Reference shall he made to C57. 12.00 latest revision with respect to cooling class and temperature rise of oil and windings. (‘57. 12.00 Clause 5.11.1.2 recognizes ‘oghcr winding rises for unusual ambient conditions or special applications” that inlrs inclusion of arc furnace transformers. Ratings up to and including 10 0(X) kVA shall be water-cooled (ONWN, ONWF). Ratings above 10 000 WA shall be lbrced-oil-cooled with firced-water cooler (OFWF) or forced-oil-cooled with forced air (OFAF).IEEE C57.17 pdf free download.
