IEC 62271-2:2003 pdf free download

IEC 62271-2:2003 pdf free download
IEC 62271-2:2003 pdf free download.High-voltage switchgear and controlgear
7.3 Analysis
The general procedure is as follows:
a) To establish, using experimental data stated in 7.2, a mathematical model of switchgear and their assemblies in order to assess their dynamic characteristics. Considering the modularity of switchgear and their assemblies, the mathematical model implemented and calibrated for the test-set may be extended to a complete substation, provided that the right adaptations, related to the structural differences existing for the different modules, are considered.
b) To calibrate the mathematical model by taking into account the non-linearities of the dynamic response of the test-set assessed during the experimental activity described in Annex A.
c) To determine the response, in the frequency range stated in 6.5, using either of the methods described in the following subclauses, but other methods may be used if they are justified.
7.3.1 Acceleration time-history method of calculation
When the time-history method is employed for seismic analysis, the ground motion acceleration time-histories shall comply with the RRS (see Table 1 ). Two types of superimposition may generally be applied depending on the complexity of the problem:
a) Separate calculation of the maximum responses due to each of the three components (x and y in the horizontal, and z in the vertical direction) of the earthquake motion. The effects of each single horizontal direction and the vertical direction shall be combined by taking the square root of the sum of the squares, i.e. (x 2 + z 2 ) 1 /2 and (y 2 +z 2 ) 1 /2 . The greater of these two values is used for dimensioning the switchgear and their assemblies.
b) Simultaneous calculation of one of the horizontal directions and the vertical direction (x with z) and thereafter calculation of the other horizontal direction and the vertical direction (y with z). This means that after each time step of the calculation all values (forces, stresses) are superimposed algebraically. The greater of these two values is used for dimensioning the switchgear and their assemblies.