Introduction To Power Flow


Introduction


Power flow studies are great of importance in many applications of power system such as planning and designing the future expansion of power systems as well as in determining the best operation of existing system.
The principle information obtained from power flow study is
the magnitude and phase angle of the voltage at each bus and the real and reactive power flowing in each line. However, much additional information of value is provided by the print out of the solution from computer programs used by the electric utility companies.

The following table shows summery of some important practical applications of load flow studies and corresponding description:

Application
Description
Transmission planning

Use load flow to check for overloads ,voltage problems, and to identify location of network reinforce-ments
Contingency analysis
Teat for effect line and/or generator outages
VAR/ Voltage analysis
Evaluate effectiveness of VAR/voltage devices
Transfer capability analysis

Test for inter-utility power transfer limits.
On line control, security
analysis
Analyze effectiveness of corrective measures to alleviate emergencies 

Table (1-1) Practical application of load flow studies


Importance Of Power Flow Study


The importance of power flow study can be summarized as following:

The total generation power in the network supplied from the generator station must equal the demand plus the network losses at each moment , the individual generator outputs must be closely maintained at predetermined set points. It is remember that the demand undergoes slow but wide changes throughout the whole day. This means that a load flow configuration that fits the demand of a certain hour of the day may look quite different the next hour.

Transmission links can carry only power less than their stability or thermal limits (security constraints to avoid any over loads ).

The voltage level of the system buses are necessary to keep within certain tolerance (upper & lower limits ) .

The power system must fulfill certain contractual power –scheduling commitment via its tielines to neighboring systems.
The effects of system outage (generation units or transformers or lines) can be minimized by proper prefault power flow strategies.
Power flow analysis are very important in thy planning stages of new networks or extension to existing ones.
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Ahmad Mohammad

Hi. I’m Designer of Mawsoo3a Blog. I’m Electrical Engineer And Blogger Specializing In Electrical Engineering Topics. I’m Creative.I’m Working Now As Maintenance Head Section In An Industrial Company.

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