Transmission System Operations

System Restoration The earlier courses in this series have mainly dealt with the elements of the power system when it is operating in its normal state. The previous course extends that knowledge into some of the abnormal situations that can occur on the power system and describes how different pieces of apparatus can act under those conditions. Several actual incidents are described. This course extends that discussion to the situation where the system or a part of it collapses and the possibilities for system restoration.

At the end of this course you should be able to:

• List 3 critical parameters to be determined after a major system upset
• Describe the importance of communications
• List 3 items of circuit breaker status
• List 3 events which can cause the breakers to open
• Describe how cold weather affects breakers
• Suggest alternatives possible if a control center is blacked out
• List 3 reasons to sectionalize a blacked out system
• List 3 things to be done before intentionally separating from a system that is descending into a blackout
• Describe the procedure for reenergizing a blacked out system from a neighboring healthy system
• Describe the procedures for connecting generation and load
• Describe the requirement for re-establishing direct current connections
• Describe how to establish a power source within a blacked out system
• Describe how to pick up load and transmission from a power source within a blacked out system
• Understand the black start characteristics of different types of power plants.
• List the minimum requirements for standby power at a fossil steam plant
• Explain why nuclear plants are not suitable for black start
• Describe the characteristics of heating and lighting loads
• Describe the characteristics of motor loads
• Describe the characteristics of thermostatically controlled loads
• Draw the curve of current vs. time for a reconnected feeder
• List 4 ways that the inrush on a re-energized feeder can be reduced
• Describe the precautions required when starting synchronous condensers after a blackout
• Define the amount of synchronized generation which must be on line to start a synchronous condenser
• Define the amount of synchronized generation which must be on line to pick up a block of load
• Prioritize feeders for pick-up
• List 4 things to be considered when picking up load
• Draw a re-energization route map for a part of a system
• Describe how lines may trip out again if oscillations occur
• List 6 ways of reducing oscillations when rebuilding the system
• Describe the precautions necessary when synchronizing islands
• Explain how to control frequency when picking up loads
• Describe how to prepare a system which will be islanded deliberately
• List the limitations of fossil fired steam plants in islanded operation
• Describe the operation of nuclear units in an island
• Recognize the different perspective of independent power producers
• List allowable normal and emergency voltage deviations
• Describe how reactors and load current can be used to reduce the voltage rise on transmission lines
• Describe why cables have a much greater voltage rise than overhead lines
• Describe how parallel and series ferroresonance occurs
• Draw typical wave forms of a system experiencing ferroresonance
• Explain how a trapped charge can cause high voltage on a transmission line
• List 4 communication media which could be used for system control
• Estimate how long to wait before starting to pick up lines in the absence of any communications
• List 2 tests which can be performed without disrupting customers
• Describe how restoration simulations could be carried out
• List 10 training priorities suggested by NERC
• List the classes of disturbances which must be reported to the Department of Energy in the United States
• Define the 3 disturbance severity levels used by CIGRE
• List the 9 initiating causes used by CIGRE
• Recognize the importance of gathering post disturbance information