How to make grounding of video surveillance in permafrost

It’s always hard to perform equipment grounding in permafrost. Such a ground has a high resistivity, and it is hard and expensive to place ground electrodes to a great depth in a frozen ground. The task is more complicated when the protected equipment is located in the city streets, with not much space for ground electrodes. ZANDZ technical center has recently faced such a problem.

We got a request from Yakutsk to calculate grounding of a video surveillance system installed on supports. ZANDZ engineers were quick to find a proper solution: the best choise for complicated permafrost and stony grounds – electrolytic grounding. It enables to effectively protect the equipment and make the ground electrode compact. You can read more about advantages of this grounding here. One set of electrolytic grounding ZANDZ ZZ-100-102-6МВ should be used to protect one support; it is installed 3 meters from the support base. Below you will see a detailed calculation of the grounding device.

Task

Repeated grounding for video surveillance supports in Yakutsk. The events should be carried out in accordance with EIC 7th edition Chapter 1.7.

Solution

The set of measures on providing necessary requirements to video surveillance grounding is presented as follows:

Image 1 – Plan of grounding device elements layout

Calculation of grounding device resistance

According to the customer’s requirement the calculated ground resistance of permafrost is taken equal to 1500 Om*m.

Warning. In case of inaccuracy and limitedness of the ground data offered by the customer, the given calculation of the grounding device is considered to be incorrect. In case of getting a different ground resistivity from the calculated one, it is necessary to carry out calculation with the actual value. When the normalized resistance of the grounding device is exceeded, it is necessary to change the structure:

Horizontal electrode resistance:

where C – non-dimensional coefficient, describing the content of electrolyte in the surrounding ground;

Lверт  - ground electrode length, m;

d – ground electrode diameter, m;

p – ground resistivity, Om*m.

Grounding device impedance:

where n – number of kits;

k_исп  – use ratio

Calculated grounding device resistance is 28,3 Om, which is less than the required value of 30 Om in accordance with point 1.7.103 of EIC.

Components for grounding video surveillance systems

 

Do you have questions on grounding in the conditions of the far North and permafrost? Ask help at ZANDZ Technical center!

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