What is the safe distance for RF antenna under 220KV high voltage equipment?

[tony_lth]

Hi, Gurus,
I need to install some a RF component with antennas in the 220KV high voltage station field.
I suppose to install the antenna right in the center of the 220KV high voltage field, but I have some concerns.
I don't worry about lighting, because the 220KV equipment has almost perfect lighting-free grids.
I saw some camera with iron shell in the field, which is about 1.5 meters height.
So I want to install my RF component with antennas in the field also, and the antenna end is also 1.5m height also.
What I worry is in the heavy rain, is it safe for antennas? Do I need to install some lighting-protector between the antenna and the RF TRX?
The RF is 470M/+17dBm and 2.4G/+10dBm.
Some newspaper warn people don't use cellphone in the rain, so what is the safe distance for RF antenna under 220KV high voltage grids?
The picture is the 220KV field.
Any comment are welcome.
Best,
Tony Liu

 

[BradtheRad]

What I worry is in the heavy rain, is it safe for antennas? Do I need to install some lighting-protector between the antenna and the RF TRX?

Consider installing a static arrestor.

Make a drip loop in the cable.

Place your equipment so it's not hit by streams of water falling from electrified wires.

Your photo shows people among the equipment. Since it seems safe for humans then your equipment should be okay too.

 

[tony_lth]

BradtheRad,
Thanks for reply.
The antennas are FRP ones, so the electricity should only hit the NJ-connector-outer, which is GND, and linked the iron shell of the component, finally the iron shell links to the PE.
So I guess even without surge protective devices as aforesaid by you, the component should be OK, because the power supply board in the component can handle the surge on the ground.
Do you think my idea is OK?
Best,
Tony Liu

 

[vfone]

In some countries the safety standards for electric lines above 110kV, the distance from the high-voltage lines to the highest point of the antenna (or other objects) should be greater than H+3m, where H is the distance from the highest point of the antenna to the ground.
Sharp points and humidity increase possibility of creating corona effect under high-voltage lines.

 

[tony_lth]

Hi, vfone and others,
In the link, https://www.signs.org/codes-regulations/federal-regulations/power-line-safety,
In table A, it say that minimum clearance distance is 20 feet for 220KV.
But in table T, the minimum clearance distance is 10 feet,
So what's the difference between them?
Best,
Tony Liu

 

[vfone]

I think these kind of safety standards differ from country to country, but sure they cover the same situation with more or less stringent regulations.
In my opinion the standard that I mentioned above make more sense, because it takes in consideration the distance of the highest point of the object from the ground.
Higher the object from the ground it expose it more in open space, and the distance to the high-voltage lines should be increased with the amount of its height + a margin.

I don't understand either why in the table is a smaller distance when traveling with no load. Maybe they don't care about damages if there is no load
Hopefully who wrote that standard knew what he was doing..

 

[JohnBG]

this antenna has to be safely anchored to stand winds up to 120km/h, at least. This particular grid operator requiring a 1.5m rod or antenna wiring that you intend to install to stand higher wind speed.

Have you asked the grid operator for written permission?

They may only allow approved installers. If so have you contacted any of these installers so the installer may have already placed wireless alarms and sensors for same company?

 

[tony_lth]

Hi, JohnBG,
That's a good point. Thanks a lot.
Best,
Tony Liu