Webinar "Grounding and lightning protection for electrical substations", page 1

Grounding and lightning protection for electrical substations

– Today, it is our fourth webinar of the "Simply about installing grounding and lightning protection" series. Let me remind you. In our previous webinars, we examined the regulatory documents that the electrical specialists work with, and looked into such facilities as private houses, apartment buildings, and commercial facilities. Today, we will proceed to the more complex facilities, such as electrical substations. We will also consider the traditional issues of how to correctly perform calculations and installation of the lightning protection grounding and meet all the respective requirements. Moreover, upon request of the webinar participants, we have included the issue of arranging the grounding and lightning protection for the diesel electrical station.
We will talk about it in the end of the webinar. This webinar series is led by our lecturer, Sergei Tolstopyatov. He is the director general of OOO NGN Group, and an experienced electrical specialist as well as the ZANDZ.com Club expert. The ZANDZ technical specialists are also present in the webinar. They will respond to your questions. Please ask them in the chat. Upon the request of our technical specialists, I made a questionnaire in the respective tab. Please visit it at the end of the webinar and answer all questions. It will not take longer than three minutes. Now, my introduction is over. I give my turn to the lecturer. Good afternoon, Sergei Alekseevich!

– Hello. Let me greet you in our next webinar. Please do not forget to take our questionnaires. The webinar will be held as follows. I will show you the files and tell about them. In the course of the story, you may ask your questions. We have two engineers here who will respond to them quickly. I will answer all questions that have not been answered by our engineers or those that will be asked for me personally. Aleksey will control this and help me. He will concentrate them and read at the end of the webinar.

Substation grounding purpose

– Well, the substation grounding has the following purposes:

1. Electrical safety for the personnel. I think it is the major one. In the normal and emergency modes, i.e. at short circuits, we must not have an electric shock.
2. Electrical compatibility of the equipment.
3. Reliable grounding of the lightning protection devices and overvoltage limiters.
4. Work grounding installation.

The grounding device is also required for the secondary substation equipment that serves to protect the substation in emergencies and to automate the processes. 
 

Equipment grounding

– Depending on the neutral type, different requirements are applied to the grounding device resistance. For the substation with the voltage of 110 kV and more, in accordance with electrical installations code 1.7.90, the standard for the electrical units with the efficiently grounded neutral wire is specified and is usually 0.5 Ohm. 
 

Grounding calculation

– The grounding calculations can be performed in the software developed by the Energy Institute named after G. M. Krzhizhanovsky and by the ZANDZ Technical Center. To do this, we need to receive the requests from you. Do not hesitate to ask questions in any form. We will help you in navigating and perform the design for grounding the high-voltage electrical substations.

Substation grounding

– In order to equalize the potential, the grid step reduces down to the grid having a 1-meter step in the workplaces near the equipment. The smaller the grid, the lower the step and touch voltages. To reduce the pulse touch at the current entry points as well as the pulse current of the lightning, the vertical electrodes of up to 5 meters are installed. Points with the vertical grounding devices are shown in the picture.