XZERES Wind Skystream 3.7, Руководство пользователя

Страница: 49 / 56

Skystream Owner’s Manual
3-CMLT-1054 Rev O XCO 1191
Pg. 49
Determine the Topography
Inspect the topography of the area in which the turbine is installed and select the one category that best
describes the topography:
• Isolated Flat Land: No structures present within a circle of radius three times the height of the
turbine (with the turbine at the center of the circle)
• Knoll / Hill
• Un-isolated Flat Land: Smaller structures present within a circle of radius three times the height of
turbine (with turbine at center of the circle)
Permitted Annual Number of Critical Events (Nc)
Determine Nc. Three “Annual Number of Critical Event” options are provided in the tables. The least
protective option is 1 /100 (1 in 100); the most protective is 1/10000 (1 in 10,000).
Warning: If there is risk of injury or danger to human life, then maximum allowed Nc is generally
1 in 100,000 or less, depending on laws of various states or countries.
As Skystream installations on relatively short towers (like 33 ft - 70 ft / 10 m - 21 m) do not significantly
increase risk of injury or danger to human life, the Efficiency (E) is calculated with higher values of Nc
(for example, 1/1000 is larger than 1/100,000).
However, Nc must be chosen to comply with local electrical safety laws. Some authorities may require
Nc = 1/100,000 for better protection. The result of choosing such a low Nc would mean that a lightning
protection system with Level 1 protection will need to be installed.
Table 2 - Lightning Protection Efficiency for 45 ft (14 m) Towers
Isolated Flat Land Hill or Knoll Non-Isolated Flat Land
Ng efficiency efficiency efficiency
Nc =
1/100
Nc =
1/1000
Nc =
1/10000
Nc =
1/100
Nc =
1/1000
Nc =
1/10000
Nc =
1/100
Nc =
1/1000
Nc =
1/10000
0.01 0.001 0.0001 0.01 0.001 0.0001 0.01 0.001 0.0001
1 -0.427 0.875 0.986 0.287 0.929 0.993 -1.853 0.715 0.971
2 0.287 0.929 0.993 0.643 0.964 0.996 -0.427 0.857 0.986
3 0.524 0.952 0.995 0.762 0.976 0.998 0.049 0.905 0.990
4 0.643 0.964 0.996 0.822 0.982 0.998 0.287 0.929 0.993
5 0.715 0.971 0.997 0.857 0.986 0.999 0.429 0.943 0.994
6 0.762 0.976 0.998 0.881 0.988 0.999 0.524 0.952 0.995
7 0.796 0.980 0.998 0.898 0.990 0.999 0.592 0.959 0.996
8 0.822 0.982 0.998 0.911 0.991 0.999 0.643 0.964 0.996
9 0.841 0.984 0.998 0.921 0.992 0.999 0.683 0.968 0.997
10 0.857 0.986 0.999 0.929 0.993 0.999 0.715 0.971 0.997
11 0.870 0.987 0.999 0.935 0.994 0.999 0.741 0.974 0.997
12 0.881 0.988 0.999 0.941 0.994 0.999 0.762 0.976 0.998
13 0.890 0.989 0.999 0.945 0.995 0.999 0.781 0.978 0.998
14 0.898 0.990 0.999 0.949 0.995 0.999 0.796 0.980 0.998
15 0.905 0.990 0.999 0.952 0.995 1.000 0.810 0.981 0.998
16
0.911 0.991 0.999 0.955 0.996 1.000 0.822 0.982 0.998
17
0.916 0.992 0.999 0.958 0.996 1.000 0.832 0.983 0.998
18
0.921 0.992 0.999 0.960 0.996 1.000 0.841 0.984 0.998
19
0.925 0.992 0.999 0.962 0.996 1.000 0.752 0.985 0.998
20
0.929 0.993 0.999 0.964 0.996 1.000 0.857 0.986 0.999
30
0.952 0.995 1.000 0.976 0.998 1.000 0.905 0.990 0.999
40
0.964 0.996 1.000 0.982 0.998 1.000 0.929 0.993 0.999
50
0.971 0.997 1.000 0.986 0.999 1.000 0.943 0.994 0.999
60
0.976 0.998 1.000 0.988 0.999 1.000 0.952 0.995 1.000
70
0.980 0.998 1.000 0.990 0.999 1.000 0.959 0.996 1.000