TRANSMISSION LINE ARRESTER STANDARD GUIDELINES

Line arresters are not specifically addressed in C62.11-1999, although the arresters used in these applications are part of the standard. Most of the test requirements that apply to line arresters are based on station requirements or distribution class requirements.

When specifying line arresters, it should be noted that the following points are inherent to C62.11-1999.

1. Lightning energy handling capability can be a major factor in selecting line arresters depending on their application. The requirement of lightning related energy is typically much more significant for lines than stations. Although present standards do contain some lightning-related tests, there is not presently an accepted test to quantify the lightning energy handling capability of surge arresters. Published energy handling capability of arresters is typically based on switching-related tests.

2. Heavy-duty distribution arresters may be subjected to more severe lightning-related tests than station class or intermediate class arresters. Although it is common belief that arrester lightning energy capabilities increase from heavy-duty distribution to intermediate to station, the present standards do not necessarily prove this through testing.

3. The 100-kA test for heavy-duty distribution arresters should not be confused with an arrester surviving a 100-kA lightning stroke. First, the 100-kA test is a 4 x 10 ms wave that has much less energy than a typical 100-kA lightning stroke. Second, the 100-kA tests allow up to 5 minutes before the arrester is connected to MCOV to prove thermal stability.

4. Short-circuit tests permit polymer arresters to fall apart as long as the pieces fall within specific areas. The tests allow 2 minutes before the arrester must self-extinguish. These allowances in the present standards may not be acceptable for certain areas on a line right-of-way.

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