# Number of Suspension Insulators for a Given Voltage Level

by jegues
Tags: insulators, number, suspension, voltage
 P: 1,067 Hello all, I'm currently designing all the structure, equipment and grounding for a 230-115kV terminal substation, and for our dead end connections consisting porcelain ball & socket type suspension insulators we are given the number of insulators required for each voltage level. (i.e. 14 for 230kV and 9 for 115kV) On what basis do they determine that 'X' number of insulators are needed for a voltage level of 'Y'? Is it the dry arcing distance? Is it the creepage distance? Is it a combination of multiple factors, or does one particular factor mostly dominate over the others? Also I've often heard that there is a rule of thumb through which one can guess at the voltage level of a given transmission line by counting the number of insulators in a given insulator string, is this true? Thanks again!
 P: 1,760 Forty years ago I worked with an engineer who had worked at a power station. He told me how to estimate the voltage of high tension power lines (in the US). He knew the standard transmission voltages, which I have long forgotten, and it was simply a matter of counting the number of insulators, multiplying by 10kV and "rounding" to the nearest standard voltage. All I still remember is the 10kV per insulator.
 PF Patron P: 1,736 Here are three manufacturers that give descriptions and specifications of their high voltage insulators: http://www.ceramic-insulator.com/showproduct.asp?id=80 http://sunelectric.en.alibaba.com/pr...nsulators.html http://electrical-engineering-portal...***-insulators
PF Patron