IEEE C62.22:1991 pdf download.IEEE Guide for the Application of Metal-Oxide Surge Arresters for Alternating-Current Systems.
This guide covers the application of metal oxide surge arresters (see IEEE Std C62.11-1987 [9])1 to safeguard electric power equipment against the hazards of abnormally high voltage surges of various origins. Such overvoltages may cause flashovers and serious damage to equipment and thereby jeopardize the supply of power to users. It is essential to prevent this by the proper coordination of surge-protective devices with the insulation strength of the protected equipment.
The subject is broad, with many ramifications, and it requires a volume of considerable bulk to explain all possible cases in detail. Section 3 of this guide covers the basic cases for stations used to supply and switch electric power transmission, subtransmission, or distribution feeders. Information is included in Section 4 on application of arresters for protection of overhead and underground distribution systems, all distribution transformers, and other electric distribution equipment.
Step-by-step directions toward proper solutions for various applications are provided. In many cases, the prescribed steps are adequate. !Iore complex and special situations requiring study by experienced engineers are described, but specific solutions may not be given. These procedures are based on theoretical studies, test results, and experience.
1.2 Definitions
1.2.1 Overvoltages
1.2.1.1 Overvoltage. Abnormal voltage between two points of a system that is greater than the highest value appearing between the same two points under normal service conditions. Overvoltages may be low-frequency, temporary, and transient (surge).
1.2.1.2 Surge. A transient wave of current, potential, or power in an electric circuit; see
IEEE Std C62.1-1989 [8].
1.2.1.2.1 Lightning Surge. A transient electric disturbance in an electric circuit caused by lightning; see IEEE Std C62.1-1989.
1.2.1.2.2 Lightning Overvoltage. The crest voltage appearing across an arrester or insulation caused by a lightning surge.
1.2.1.3 Switching Overvoltage. Any combination of switching surge(s) and temporary overvoltage(s) associated with a single switching episode.
1.2.1.3.1 Switching Surge. A heavily damped transient electrical disturbance associated with switching. System insulation flashover (see 1.2.4.7) may precede or follow the switching in some cases but not all.
1.2.1.3.2 Temporary Overvoltage. An oscillatory overvoltage, associated with switching or faults (for example, load rejection, single-phase faults) and/or nonlinearities (ferroresonance effects, harmonics), of relatively long duration, which is undamped or slightly damped.
1.2.1.3.3 Coefficient of Grounding (COG). The ratio, EIJG’ELL (expressed as a percentage), of the highest root-mean-square (rms) line-to-ground power-frequency voltage E1 on a sound phase, at a selected location, during a fault to ground affecting one or more phases to the line-to-line power-frequency voltage ELL that would be obtained at the selected location with the fault removed.
1.2.1.4 Traveling Wave. The resulting wave when an electrical variation in a circuit such as a transmission line takes the form of translation of energy along a conductor, such energy being always equally divided between current and potential forms; see IEEE St.d 100-1988 [11].IEEE C62.22 pdf download.