ANSI/IEEE C37.71-1984 pdf free download.IEEE Standard for Three-Phase, Manually Operated Subsurface Load Interrupting Switches for Alternating-Current Systems.
1.1 Scope
ANSI/IEEE C37.71-1984 applies to three-phase, group operated, 60 Hz, subsurface, load interrupting switches with maximum ratings of 600 A and 38 kV, and utilizing separable insulated connectors.
1.2 References
When the following standards referred to in this document are superseded by a revision, the latest revision shall apply.
[1] ANSI C37.85-1972 (Rl978), American National Standard Safety Requirements for X-Radiation Limits for AC High-Voltage Power Vacuum Interrupters Used in Power Switchgear.’
[2] ANSI C57.l2.26-1975, American National Standard Requirements for Pad-Mounted Compartmental-Type. Self-
Cooled, Three-Phase Distribution Transformers for Use with Separable Insulated High-Voltage Connectors, High-Voltage; 24940 Grd Y/14,400 Volts and Below; 2500 kVa and Smaller.
[3] ANSI/IEEE Std 4-1978, Standard Techniques for High-Voltage Testing.
[4] ANSI/IEEE Std 386-1977. Separable Insulated Connectors for Power Distribution Systems Above 600 V.
[5] ANSI/IEEE Std 454-1973 (R1979), Recommended Practice for the Detection and Measurement of Partial Discharges (Corona) During Dielectric Tests.
2. Definitions
The definitions of terms contained in this standard, or in other standards referred to in this document, are not intended to embrace all the legitimate meanings of the terms. They are applicable only to the subject treated in this standard. For additional definitions see ANSI/IEEE C37.1OO-l981.
bus: (as used in this standard). A three-phase junction common to two or more ways.
subsurface switch: A submersible switching assembly suitable for application in a below-grade enclosure that does not allow space for personnel access.
surface operable: A term indicating that the switch and its accessories are operable from above grade. way: A three-phase circuit entrance to a switching assembly.
switched way: A way connected to the bus through a three-pole, group operated switch. tapped way: A way solidly connected to the bus.
NOTE — For clarification of definitions, see Fig I.
3.2 Unusual Service Conditions
3.2.1 Abnormal Ambient Temperatures
Switches may be applied at higher or lower ambient temperatures than specified, but performance may he affected. Special consideration shall be given to these applications.
3.2.2 Altitudes Above 3300 ft (1000 m)
Switches may he applied at altitudes higher than 33(M) ft (1000 m). However, the basic impulse insulation level and rated maximum voltage of air insulated switches shall be multiplied individually by the correction factor shown in Table 1, column (3). to obtain values at which the application may he made.
In addition, the continuous current rating shall he multiplied by the correction factor shown in Table I, column (4). However, switches designed for standard temperature rise may be used at normal current rating without exceeding total temperature limits, provided that the upper ambient temperature does not exceed the ambient allowed in 3.1 multiplied by the factor shown in Table 1, column (5). (Other ratings are not affected by altitude.) ANSI/IEEE C37.71-1984 pdf download.