Received voltage, transmission power system

Click For Summary

Discussion Overview

The discussion revolves around calculating the receiving end voltage for a power transmission system with a specified load of 10 MW at a power factor of 0.9, sourced from a 66 kV substation. Participants explore various methods for determining the voltage drop and the current needed for these calculations, as well as the implications of iterative methods in achieving accurate results.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant presents initial calculations for transmission line impedance and seeks confirmation on the correctness of their approach, specifically regarding the voltage drop and the method to find current.
  • Another participant suggests using an iterative method to solve the problem, emphasizing the importance of referring all values to a single voltage level and calculating backwards from the load to the source.
  • A request for clarification on starting the calculations at a chosen voltage level of 132 kV is made, along with a question about what constitutes an acceptable deviation in results.
  • Another participant proposes an alternative method involving calculating the current drawn from the load and using it to find the voltage at the source, suggesting a threshold for deviation to determine when to iterate.

Areas of Agreement / Disagreement

Participants present multiple methods for solving the problem, indicating that there is no consensus on a single approach. The discussion remains unresolved as participants explore different techniques and clarify their understanding of acceptable deviations.

Contextual Notes

Participants express uncertainty regarding the definitions of acceptable deviation and the iterative process, as well as the specific calculations needed to determine current and voltage drop. There are also unresolved mathematical steps in the proposed methods.

greg997
Messages
105
Reaction score
2
Perhaps sb is able to point in the right direction. The task is to calculate the value of the receivig end volatge, for a load of 10 MW at 0.9 pf taken from 66 kV substation.
First I calculated the transmission line impedance
Zlinebase=(Vbase^2)/MVAbase
Zlinebase=132^2/100=174.24Ohm
Zlinepu= 150/174=j0.862
Sbase= 100 MVA
Load impedance = S=P+jQ
S=10+j4.84
Spu=0.1+j0.048 MVA
T1= j0.1 pu and T2= j0.12 pu
So the total impedace = T1+T2+Line+Load= j0.1+j0.2+j0.862+ 0.1+j0.048= 0.1+j1.21 ohm
Is that correct?
I know that the received volatge is Vr= Vs - Voltage drop. But how can I find the voltage drop? I need current for that, so how to find current?
Any help appreciated.According to MATLAB simulation the received voltage shoud be 57kV Line rms. Is that correct?
 

Attachments

  • 1.JPG
    1.JPG
    11.5 KB · Views: 523
Last edited:
Physics news on Phys.org
Iteration is one simple an accurate way to solve it.

First of all refer all your values to one voltage level.

Assume 66<0 V at the load, calculate backwards to the source, compare your calculated voltage to the original source voltage. If deviation is large, do another iteration with corrected load voltage. Repeat until deviation is acceptable.
 
Could you please show me how to start with it? If I choose the one voltage level to be 132k then what next? And what do you mean by acceptable deviation? If I got 10900 Vs then is it acceptable?Thank you
 
There are other methods for solving the problem. If you don't know(or have learned) this method maybe your teacher thinks of another method.

But to help you on the way. I would choose V_load = 66kV<0 at the load.

Calculate the current drawn from the load.

Then calculate the voltage at the source; V_calc = V_load + sqrt(3)* Z*I

Compare this voltage to the original source voltage (ref. 66kV) If deviation is over, let's say 5%, do another iteration.

New voltage at load is: 66kV * V_load / V_calc =

Repeat process until deviation is under "acceptable %".

A bit hard to explain in text but hope you get the picture.
 

Similar threads

Symmetrical component example: can't understand solution
  • · Replies 1 ·
Replies
1
Views
2K
Improving Electrical Supply System for Lower Fault MVA: Analysis and Solutions
  • · Replies 2 ·
Replies
2
Views
3K
Question on: Smith charts, power and transmission lines
  • · Replies 1 ·
Replies
1
Views
1K
Electrical Engineering, power system, transmission line
  • · Replies 10 ·
Replies
10
Views
2K
Calculating Line Voltage and Power Factor in a 3-Phase System: A Case Study
  • · Replies 1 ·
Replies
1
Views
2K
Transmission Line, Max Real Power Transfer
  • · Replies 1 ·
Replies
1
Views
2K
Determine the load voltage levels in feeder systems
  • · Replies 15 ·
Replies
15
Views
2K
Transmission line with 2x termination
  • · Replies 6 ·
Replies
6
Views
1K
How transmission lines deliver (established?) power from generator
  • · Replies 8 ·
Replies
8
Views
3K
Answer: Calculating Average Power Delivered to Load Resistors on 50 Ohm Line
  • · Replies 3 ·
Replies
3
Views
3K