IEC 62231-1-2015 pdf download.Composite station post insulators for substations with AC voltages greater than 1000Vupto245kV- Part 1: Dimensional, mechanical and electrical characteristics.
Composite station post insulators are characterized by the following mechanical and dimensional characteristics, values of which are specified in Tables 1 and 2:
• maximum design cantilever load (MDCL)
• specified cantilever load (SCL),
• specified compression load (SCoL),
• specified tension load (STL),
• specified torsion load (ST0L),
• insulator height,
• minimum creepage distance,
• maximum diameter of insulating part.
• metal fitting (end fitting) arrangement (see Clause 9).
Tables la and lb give a minimum creepage distance for each insulator along with the highest voltage for equipment based on a unified specific creepage distance (USCD) of 34,7 mm!kV or 43,3 mm/kV (phase-to-earth). This voltage is given for information only. These USCD are regarded as a representative value of the medium (c) and heavy (d) pollution classes as defined in IEC 60815-1. Table 2 gives similar information for insulators based on North American practice, with a USCD of 27,8 mm/kV corresponding to the light pollution class (b). Creepage distances different to those given in the Tables can also be considered for the insulators intended for use in various polluted conditions. Further information on USCD and selection of the insulators for polluted conditions can be found in IEC 60815-1 and 60815-3.
5 Electrical characteristics
Composite station post insulators are characterized by the following electrical characteristics. values of which are specified in Tables I and 2.
• dry lightning impulse withstand voltage,
• wet power frequency withstand voltage.
6 Designation
Composite station post insulators are designated in Tables la, lb and 2 as follows:
• by the letters CSP or NCSP followed by a number indicating the dry lightning impulse withstand voltage in kilovolts;
• then followed by the letter A or B. representing the pitch circle diameter of top and bottom metal fittings (A:76mm, B:127mm);
• and then followed by two numbers separated by a dash, which indicate the maximum design cantilever load (MDCL) in kilo Newtons with two digits and the minimum creepage distance in millimetres.
• For example, designation NCSP1O5OB-06-5030 stands for the composite station post insulator with a dry lightning impulse withstand voltage of 1 050 kV, a pitch circle diameter of 127 mm, a maximum design cantilever load of 0,6 kN and a minimum creepage distance of 5 030 mm.
NOTE Each designation of composite station post insulators means:
CSP: Composite station post insulator
NCSP: Composite station post insulator for Norlh America practice
7 Marking
The composite station post insulator shall be marked in accordance with IEC 62231.
8 Tolerances
The dimensions of creepage distance and maximum diameter of insulating part given in Tables 1 and 2 are the absolute minima and maxima, respectively; hence no tolerances are applicable. The tolerances of the insulator heights are given in Tables 1 and 2. Tolerances of parallelism, eccentricity, and angular deviation shall be in accordance with IEC 62231.
The dimensions and tolerances of insulators supplied in compliance with this standard shall be shown on the manufacturer’s drawing.
9 Metal fitting arrangements
The metal fitting arrangements shall be in accordance with Tables 1 and 2. Fixing holes shall be equally spaced on the appropriate pitch circle, which shall be concentric with the axis of the insulator. Holes in top and bottom fittings shall be in line, unless otherwise specified, and they shall be so arranged as to permit the use of normal hexagon bolted heads and nuts.IEC 62231-1 pdf download.