24-12-2012, 05:03 PM
Voltage and Reactive Power Planning and Control
Voltage and Reactive.ppt (Size: 1.58 MB / Downloads: 72)
Purpose of Presentation:
Identify key challenges for all transmission, distribution in maintaining voltage and reactive power control and reliability
Scope of Presentation:
Fundamentals of voltage and reactive power.
Relationship between voltage and overall reactive power and overall system reliability.
Voltage & Reactive power planning And Assessment Practices.
What is Reactive Power?
While active power is the energy supplied to run a motor, heat a home, or illuminate an electric light bulb, reactive power provides the important function of regulating voltage.
If voltage on the system is not high enough, active power cannot be supplied.
Reactive power is used to provide the voltage levels necessary for active power to do useful work.
Reactive power is essential to move active power through the transmission and distribution system to the customer.
How Are Voltages Controlled?
Voltages are controlled by providing sufficient reactive power control margin to “modulate” and supply needs through:
Shunt capacitor and reactor compensations
Dynamic compensation
Proper voltage schedule of generation.
Voltages are controlled by predicting and correcting reactive power demand from loads
Voltage Must be Maintained Within Acceptable Levels:
Under normal system conditions, both peak or off peak load conditions, the voltages need to be maintained between 95% and 105% of the nominal.
Low voltage conditions could result in equipment malfunctions:
Motor will stall, overheat or damage
Reactive power output of capacitors will be reduced exponentially
Generating units may trip.
High voltage conditions may:
Damage major equipment – insulation failure
Automatically trip major transmission equipment.
Conclusion:
The August 2003 Blackout study team concluded that inadequate voltage and reactive power planning were contributing factors to the incident.