What should be the general procedure of back feeding the electrical equipment through 400 kV line?

There are many obstacles, before you get ready with a back feeding link.
In first stage, the advance of both Generation plants or S.S.'s must be planned to get the link ready between them before the back fed is needed.
If not ready, then get ready with daily penalties. Review your contract in small letters.

Second stage, be sure the plant to be fed is really ready, when you are not ready and conciliate the finish of the link.

Third stage: If you are not ready but the plant to be fed is, look for a portable Generation plant with enough capacity and voltaje, to supply the energy for testing of the plant, to be fed. Open a daily book and ask the plant manager to sign it, and record hour per hour, current, voltaje and power consumed. This way you will not to be fined.

Don't trust if the manager of the plant say that you are a brotherhood. At the end they will try to fine you some way.

If the line is already energized, power up the transformer and the busses including station service.

Not sure what you are wanting to know due to incompleteness of the question. Please provide better scenario or description, try to be more than 25 words.

In the absence to details re your constraints to use 400 kv line for. Charging equipment is technically not prudent solution. General opinions re solution will not. Help. You as there are n number of factors to. Be considered based on real scenario you. Have not described ..

Many Thanks for the Feedbacks and your posts!
Now the topic I wanted to discuss, let me explain that in detail->
We are about to commission a 100 MW Hydro power Project. Our Dry commissioning is already done. First, we are going to charge our power transformer and 400 kV cable through the 400 kV transmission line ( back charging) as the water for spinning the machine is not available.
I already prepared Electrical Sequences for opening and closing of Circuits. To brief, we have Outdoor switchyard, then GAS insulated switchgear then 400 kV cable and last Generator transformer. All these equipment will come into picture during back feeding.
Transmission line is also a new line to be synchronised with existing grid.
I require expert Advise, Experience sharing of all, problems faced etc. on this Topic.
Thanks in Advance !

If you do not have other local generators for var support you "may" have starting issue.

If you decouple the prime mover, it may help.

I personally do not see the need to motor the generator for testing, but not my station. It will likely consume 25 MW of power to run with the turbine connected and half that decoupled.

If you get it to spin at sync speed, please your power requirements. It woulld me more interesting to get a trace during breaker closing until the unit comes to sync speed.

Watch the line voltage at the other end, especially if it is a weak source.

Good luck !

As Umesh has stated, this is not a trivial exercise! The time to ask this question was in the planning stages, not just prior to commissioning. If the transmission line is of any appreciable length then someone has to tell you what the Ferranti Rise will be on this unloaded line and how it varies throughout the day.

With that information you must determine whether your equipment can tolerate the potentially high voltages and/or switching surges that may occur, plus any voltage regulation issues that may arise as your plant equipment is loaded and unloaded from the line.

I guess, part of the intention is to back feed up to the Power Generation Control Room for lighting, compressors and test Control and Protection system of generation plant is it?.
Or only to test, up to the Generation Transformer?
If it is the second stage, you do not have any problem, just give some time getting hot every part sepparate.

For the line, leave it hot enough time, while you watch, hear or search for abnormal sounds and lights.

Then for the transformer energize it and leave it for twelve hours in no load condition.

I do not know where this energy is coming from. From a Transmission line or from another Generation Plant.

I guess you have to modify your energy meters and protection system, because the energy is going backwards and you have to recalibrate relays because youir back feed is a load not a source.

Ashish pl feel free to share what your company wants to achoieve by charging equipment and to be more specific it is not advisable to keep it charged for various techno commercial implications. Like penalty applicable as per gridcode for pumping reactive power in the grid and risk of overvoltage to equipment. Anyway your plan to backcharging equipment calls for detailed risk analysis. In. Similar situation we have successfully charged 7 bay GIS station along with 2x90 mva transformer with 33 kv GIS 18 bays from 33 kv/440vstation service transformer using DG set of 1Mva with controlled voltage condition by modified field circuit. You may think on similar lines as charging of equipment for remotely set up hydro plan ( actually it may be under installation and its. Completion may take years). Here because line is available you are tempted to. Use it for charging. The method I mentioned is useful when no source is available.