24-09-2013, 12:32 PM
TYPES OF POWER SYSTEM TRANSIENTS
TYPES OF POWER SYSTEM.docx (Size: 17.63 KB / Downloads: 60)
1. Depending duration of transient:
ultrafast transient (lighting and switching)
medium fast transient (short circuit)
slow transient (mechanical oscillation)
2. According to source of transient:
Lighting transient (lighting as source)
Switching transient (closing & reclosing of switches)
TYPES:
Electrical power system contains energy storage element in the form of inductance and capacitance of electrical components and inertia of rotating machine.
So any sudden changes in such system will be raise to transients.
Ultrafast transient:
It is caused by lighting or by the sudden but normal network chances resulting for normal switching operation.
It is an electrical in nature.
It is generally lost only for few milliseconds.
This transient give rise to high voltage which provides a basic of insulation designs in the system.
Medium fast transients:
Thus transient occur for due to short circuit in the system .this causing abnormal structural change in the system.
It is the electrical in nature.
It is responsible for excess current in system.
This transient may be present in system for a long period.
Slow transient:
It is caused by mechanical oscillation of rotor of synchronous machine.
It is electro mechanical in nature.
This oscillation causes instability of the interconnected power system by putting some all machines out of synchronism.
Transient exist in the system for a much longer period of ranging from a fraction of second to a second or more.
Depending upon the control to the transient.