Overhead transmission lines
Overhead transmission lines
(OP)
Hi All,
I am working on overhead transmission lines & as I am new to this field I want your help.
I have 2 Steam generators & a 100KVA DG feeding to a 415V bus. There is no transformer at incoming line. The bus will be charged by 2 Steam generators & DG will work only in emergency condition.
Then there 8 O/G feeders going to 8 different panels. The distance between main 415V bus & these 8 panels is about 2 Km & power will be transmitted by overhead lines.
Can anybody pls help me out to find the voltage drop in transmission & what do I need to do to compensate this Voltage drop?
I guess the Vd will be 180V & is capacitor bank a good solution to this problem? If yes, what will be its size?
Pls explain with the formula..
I am working on overhead transmission lines & as I am new to this field I want your help.
I have 2 Steam generators & a 100KVA DG feeding to a 415V bus. There is no transformer at incoming line. The bus will be charged by 2 Steam generators & DG will work only in emergency condition.
Then there 8 O/G feeders going to 8 different panels. The distance between main 415V bus & these 8 panels is about 2 Km & power will be transmitted by overhead lines.
Can anybody pls help me out to find the voltage drop in transmission & what do I need to do to compensate this Voltage drop?
I guess the Vd will be 180V & is capacitor bank a good solution to this problem? If yes, what will be its size?
Pls explain with the formula..






RE: Overhead transmission lines
The same issues concern the placement of the capacitor bank. What voltage rise are you shooting for?
RE: Overhead transmission lines
I used Vd=I*1.732*(R*cos(phi)+X*sin(phi))*length/(1000*No. of runs).
Is this formula correct?
The maximum current demand is 150 Amp,P.F at generating point is 0.8 lag & load side KW rating is 80 KW. As the design is at primary stage I don't have motor details like at what PF the motors will be running.
I considered 70 sqmm copper cable's data sheet (for R & X values) as i did not have ACSR conductor current carrying rating & other details.
My basic concern is voltage drop compensation..
RE: Overhead transmission lines
RE: Overhead transmission lines
RE: Overhead transmission lines
Alan
"The engineer's first problem in any design situation is to discover what the problem really is." Unk.
RE: Overhead transmission lines
Is the method of calculating voltage drop is correct? (I will use ACSR's data sheet once I get it)
The primary use of Capacitor bank is to improve PF but can it be used for voltage level improvement? KVAr=1.732*V*I*Sin(phi)? And here I will consider V=160V(As system's Vd is 160V) and based on this I will use a CapBank.
Is it a right solution?
RE: Overhead transmission lines
RE: Overhead transmission lines
Capacitance can improve voltage drop if your load is inductive, but not enough to fix this problem.
Alan
"The engineer's first problem in any design situation is to discover what the problem really is." Unk.
RE: Overhead transmission lines
To Davidbeach: I don't have transformer here thats my main problem.
Please suggest on using 25KVAr capacitor bank on receiving end considering PF at receiving end 0.85 or 0.9.
RE: Overhead transmission lines
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Overhead transmission lines
Your choices are:
1) Transmit at a higher voltage, with appropriate transformers at either end
2) Install outrageously large conductors to keep the resistive volt-drop within acceptable limits.
Option 1 is used by the utilities, not because it is complex but because it is economically viable. The alternative is to build something akin to the Brooklyn Bridge out of copper. If you choose that option please post some photos; it will be interesting. Let me know in advance - I'll be buying shares in Rio Tinto.
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If we learn from our mistakes I'm getting a great education!
RE: Overhead transmission lines
RE: Overhead transmission lines
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If we learn from our mistakes I'm getting a great education!
RE: Overhead transmission lines
http://www.arcflashtraining.net
http://www.arc-flash-training.com
RE: Overhead transmission lines
RE: Overhead transmission lines
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If we learn from our mistakes I'm getting a great education!
RE: Overhead transmission lines
Maybe this is what the Ferrani Effect is. I will check it out.
RE: Overhead transmission lines
What about for a loaded system that did have inductive loads and therefore a lagging current however a large amount of capacitance was added so that the capacitive current is greater than the inductive current and therfore forced the overall load current to be largely leading. This is of course assuming tha the transmission line itself exhibits a predominately inductive characteristic. Or is what I am suggesting here similar to the solution that the OP is suggesting and is simply not feasable in nature?
I know that the transformer is the correct solution but just for theoretical discussion I'm curious to the results of capacitor addition for such a case.
RE: Overhead transmission lines
I just wanted to know what formula do we consider while estimating voltage drop for overhead transmission line. Do we calculate by same formula or it will change considering 1 conductor?
RE: Overhead transmission lines