IEEE C37.38-1989 pdf free.IEEE Standard for Gas Insulated, Metal-Enclosed Disconnecting, Interrupter, and Grounding Switches.
1.1 Scope
IEEE C37.38 applies to switches rated 72.5 kV and above intended for use in metal-enclosed, gas-insulated substations, including disconnecting, interrupter, and grounding switches. These switches are characterized by grounded. leak-tight metal enclosures that are tilled with a gas (most commonly sulfur hexa-tluoride, SF6) at some pressure above atmospheric, with live parts contained within the housing and insulated therefrom by the gas and by suitable solid insulation that supports the live parts in their proper position. Gas-insulated switches are normally electrically connected to and structurally joined to other gas-insulated components such as buses, gas-to-air bushings, circuit breakers, instrument transformers, cable terminations. etc. Switches may he manually or power operated.
2. Definitions
The definitions in this section establish the meanings of words in the context of their use in this document. Other terms shall he defined in accordance with ANSI/IEEE C37. 100-1987 [12] and other ANSI standards referenced in the text
design pressure: The maximum gas pressure to which a gas-insulated substation enclosure will he subjected under normal operating conditions. This is the result of the nominal gas density at initial filling plus ambient and current loading effects.
enclosure: The grounded metal part surrounding the gas-insulated switch, used to retain the pressurized gas under the prescribed conditions necessary to maintain the insulation level safely. The enclosure prevents personnel from inadvertently approaching live or moving parts contained therein and protects the internal components of the equipment against external effects.
enclosure currents: Currents that result from the voltages induced in the metallic enclosure by effects of currents (lowing in the enclosed conductors.
gas barrier insulator: An insulator specifically designed to prevent passage of gas from one side to its other.
3.2 Other Conditions That May Affect Design and Application
Where other conditions exist, they should be brought to the attention of those responsible for the design and application of these assemblies. Among such conditions are the following:
3.2.1
Exposure to damaging fumes or vapor; steam; salt air: oil vapors; hot, humid climate; excessive dust; abrasive dust; dripping water; falling dirt; explosive mixtures of dust or gases: and extreme high or low temperatures.
3.2.2
Unusual installation requirements, space or ventilation limitations, special duty, frequency or other operating requirements. difficulty of maintenance, nonstandard or unstable control voltage, and abnormal vibration (particularly seismic).
3.3 Unusual Service Conditions
The application of this equipment at other than the usual service conditions shall be considered special. Standard assemblies may he applied in unusual service conditions, hut performance may he affected, and special consideration should be given to these applications.IEEE C37.38-1989 pdf free download.