Optimal Insulator Design for Hight altitude power line 1

[miltonboss]

Hi...!

Dear friends, I'm looking for information on the influence of atmospheric pressure present at high altitudes sites on the isolation level of high voltage lines.
In estandarts IEC 71-1 are equations that relate the variables but only up to 2000 m.

Another equations in some documents is the following:

V=Vo*(P/Po)exp(N)

Vo voltage presented at standart conditions:
Presión: Po=101.3 kPa (760 mmHg)
Temperatura: T_o=20 (_^°)C ;
Humedad Absoluta: h_o=11 g/m^3

V, P voltage and presure at hight altitude.
and N depent on altitude, pollutions, insulator profile, etc.

Take note that my concern is focused ONLY IN ATMOSPHERIC PRESSURE AS INFLUENCES IN THE DESIGN OF ISOLATION OF HIGH VOLTAGE LINES.

if they have any information that could help me I would be very grateful.
thanks

 

[odlanor]

%% example
% REF: Insulation Coordination for Power Systems
Andrew R. Hileman
chap.16 - 2.8 Effect of Altitude

CFO = 20; % mm/kV withstand specific creep at sea level
a = 2; % altitude in km
m=0.5; % standard insulators
m=0.8; % for fog type insulators

tau = 1.03 * exp(-a/8.65);
m = [0.5 0.8];
CFOa = tau .^ m ;
%
% altitude 2km
% standard insulator => withstand creep = 0.8510 kV/mm
% fog type insulators => withstand creep = 0.9041 kV/mm

 

[miltonboss]

thx odlanor

But informations that considered altitude around 3000, 4000 or 5000 inclusive what is the influence of air presure over flashover voltage .???
What is the best study that dicri¿be what happen in this altitude ..'?? i apreciated all information of recent years.

Thx for you reponses

 

[odlanor]

miltonboss,
the reference is classical book of Insulation Coordination!!!
?????

 

[odlanor]

Once I participated in a project of 230kV outdoor substation, we change it to 345 kV outdoor substation because high altitude region. Finally we discover utility only used indoor 230 kV SF6 substation.
The priority is to discover the BIL used by utilities of high altitude region.

 

[miltonboss]

Dear Odlanor

Could you give more details about how to discover BIL e.g in altitud 3500 meter and 230 kv power line voltage...
How to select how many insulator use...

Best regards and thank you again for providing your information.

1t0o0n0