Power Flow Studies Essay, Research Paper
Power-flow surveies are of great importance in planning and planing the future enlargement of power systems every bit good as in finding the best operation of bing systems. The chief information obtained from a power-flow survey is the magnitude and stage angle of the electromotive force at each coach and the existent and reactive power fluxing in each line. The best manner to happen the values of the other parametric quantities is the computing machine. In our instance we use the POWER WORLDE SIMULASION PROGRAM ( PWSP ) . By utilizing this plan we can cognize what go on to the system at any clip and we can modify the system and see the alteration in the system. In this undertaking we will utilize ( PWSP ) to imitate the information of the five coach system & # 8217 ; s and besides to happen two solutions to the system.
THE DATA TABLES:
The line informations and the coach informations of a five coach system are given below:
The informations line tabular array
FROM-TO Impedance ( p.u ) Entire Line Charging ( p.u. ) Tap place ( p.u. ) MVA Rating
1 to 2 0.02+j0.072 j0.03 115
1 to 3.08+j0.288 1.05 115
2 to 3 0.06+j0.216 j0.02 69
2 to 4.06+j0.216 j0.02 57.5
2 to 5 0.04+j0.144 j0.015 57.5
3 to 4 0.01+j0.036 80.5
4 to 5 0.08+j0.288 j0.025 0.95 57.5
The coach informations tabular array
Bus Code Bus Voltage ( p.u. ) PG ( MW ) QG ( MVAR ) PL ( MW ) QL ( MVAR ) Qmin ( MVAR ) Qmax ( MVAR )
1 1.06+j0.0 & # 8211 ; – 0 0
2 1.02+j0.0 40 & # 8211 ; 25 15 20 60
3 & # 8211 ; 0 0 65 45
4 & # 8211 ; 0 0 70 35
5 & # 8211 ; 0 0 0 0
1- The simulation clip requires is two hours with speedup 60s.
2- The burden fluctuation is 100 % to 200 % during the two hours.
3- Showing the alive flows on the individual line diagram.
4-Enforce the line overloads
The individual line diagram:
By utilizing the information that are in the tabular array and the above options we draw the following individual line diagram.
Single line diagram without alteration
Problems Faced During Simulation Time:
There were many jobs in the above five coachs system. The first thing at get downing clip, the per-unit electromotive force at coach 3 was.87 p.u. , bus 4 was.87 p.u. , and at coach 5 was.93 p.u. , which are non in the scope. After 13 proceedingss line 2-4 near to bus two started to be overload. At 00:28 the same line but near to bus 4 burned. 4 proceedingss subsequently, the per-unit electromotive force at coach 2 goes down to.94 p.u. .At 00:40, line 2-3 started to be overload near to bus 2. At 01:01 line 1-2 near to bus 1 overloaded, line 2-4 besides overloaded, but near to bus 4, and & # 8216 ; Line 2-4 overheats! Protective steps take consequence & # 8217 ; massage appeared, In the same clip the system stopped working, the following massage appeared direct after the last massage was & # 8216 ; system can non Longer provide burden BLACKOUT! ! ! Simulation must Be restarted & # 8217 ; , line 2-4 was disconnected, all lines that connected to bus 2 burned, besides line 1-3 from the way of coach 3 overloaded. At that clip the per-unit electromotive forces at the coachs were, bus one 1.00 p.u. , coach two.0.85p.u. , bus three 0.55 p.u. , bus four 0.53 p.u, and bus five 0.73 p.u. . The system changed from the above diagram to the following diagram during one hr and one minute.
Single-line diagram after simulation of 01:01 hr
Parks About The System:
We have in the system two generators that give the power to the system, transmittals lines and transformers to convey the power, and the tonss. These three things consist any power system. For normal operation, the entire power supplied by the beginnings must be to the entire power used by the tonss plus the losingss that happen during the transmittal procedure. Bacillus
Greenwich Mean Time in our system when the burden varies the power that has to convey through the transmittal line more than the maximal power that can be transmitted through the line 2-4. When the line 2-4 disconnected the power that has to be supply by the other lines which means more power will be transmitted through these lines. In this instance the power will be more than the upper limit, which caused overloaded in these lines. After that the system can non work more, so it stopped.
Solutions To The System:
We faced many jobs in our system and the system stopped working before finished two-hour simulation. For that, we will present two solutions for the original system
A: First solution:
We fined that the first line overloaded was line 2-4.for that we have to allow the power be transmitted through other line from coach 2 to bus 4, but we can non set it in analogue to the original line. There is another manner to make that, by increasing the figure of the circuit from 1 to 2.By making this the power that transmitted through line 1-2 will be divided into two line. But the other lines stayed the same. After that I changed the figure of the circuit in the other lines and the transformers. By this manner the system works for two hours and this means the power transmitted through dual line non in one line. But, the per-unit electromotive force at coach 3, and 4 were non in 1.05-0.95 ring. To increase the per-unit electromotive force I put capacitance bank at bus 3 and 4. Adding capacitance bank means we supply excess reactive power to these coachs. The evaluation values for both capacitance bank is 80 ( MVAR ) .
By making that the system works for two hours without any job as in the following diagram.
Bacillus: Second Solution:
From the bus-data tabular array we fined that coach 2 has a restricting rang of ( MVAR ) between 20-60 ( MVAR ) and from the original single-line diagram we fined that the line 2-4 was the first line overloaded for that we can take this line as the 2nd solution. But, in this instance the power will be supplies by the other lines to bus 2 and 4, which will caused excess power through the other lines that will allow the other lines be overloaded. We can work out this job by altering the circuit figure from one to two, this means we doubled the lines and the transformers and this will convey the power through two parallel lines no in one. The system after these alteration works without any overload in any line. But, the per-unit electromotive force at coach 2 and 4 were non in the rang. For that we put capacitor Bankss at coach 2 and 4 with evaluation value 80 ( MVAR ) each. After all these alterations the system was simulated without any job during the two hours. The diagram of the 2nd solution after two hours simulation is:
Second solution after two hours simulation
Comparison and Discussion
The chief point that the applied scientists care about is the cost. My comparing will see this point. We can state that solution one better than solution two because:
1- we removed complete transmittal line that was in the original system ( 2-4 ) .this means we loss the cost of that line.
2- By taking line 2-4 the power will be supplied to bus 2 and 4 by the other lines, which means more power will be transmitted by these lines, which my overloaded them.
3- In the 2nd solution the capacitance Bankss have higher evaluation value ( 100 MVAR ) so the first 1 ( 80 MVAR )
4- If we want to alter the simulation clip, we will happen the first solution till take more clip to halt working than the 2nd.
The power flow surveies are really of import for any power system that will be built. And the best manner to acquire the right solution is the computing machine plan such as ( PWSP ) .This manner we can salvage a batch of many and clip.