CHAPTER 3
SIMULATION OF LINE OUTAGE
3.1 Linearised expressions for Real And Reactive Power Flow Changes In Transmission Line
3.1.1 Line outage
In a power system, when the transmission line between any two bus bars is opened, then it is known as line outage.
Let, the transmission line between two bus-bars(let, the bus numbers be Kth and Mth ) is opened. This is known as line outage between the bus-bars. Then no power transmission takes place between the bus-bars. It means, it will not take any power from the power system.
Let, the outage line ‘j’ is assumed to be connected between Kth & Mth buses. When the line is not opened, then real and reactive power flows take place in the transmission line.
3.1.2 Linearised expression for real &reactive power flows
The real and reactive power flows in a transmission line connecting buses k and m are given by,
pkm = gjvk2- gjvkvm cosδkm + bjvkvm sinδkm (3.1)
pmk = gjvm2- gjvkvm cosδkm - bjvkvm sinδkm (3.2)
qkm = bjvk2 - bjvkvm cos δkm - gjvkvm sinδkm (3.3)
qmk = bjvm2- bjvkvm cos δkm + gjvkvm sinδkm (3.4)
Where pkm : real power flow from kth bus to mth bus.
qkm : reactive power flow from kth bus to mth bus.
pmk : real power flow from mth bus to kth bus.
qmk : reactive power flow from mth bus to kth bus.
vk and vm : are the bus voltages at kth bus to mth bus.
δkm : phase angle between at kth bus to mth bus.
where
gj = rj/(rj2+xj2) and bj =xj/(rj2+xj2)
rj : resistance of jth transmission line connected between kth and mth buses.
xj : reactance of jth transmission line connected between kth and mth buses.
bji = bj- bsh,j
bsh,j = Half of the line charging susceptance of jth...