1. Survey of power system transient stability event
-- Brazilian Blackout 2009
Christine Garcia1 , Blair Johnson1 , Dr. Jing Wang2
Lenoir City High School 1 , West High School 1, Xinjiang University2
Introduction
In November of 2009, Itaipu Dam was shut down in Brazil because of an instability problem. Shutting the dam down caused a massive blackout that not only affected 18 out of Brazil’s 26 states, but its neighboring country Paraguay as well. There were many factors put into play to encourage this blackout to occur.
Power System Model
PT (Constant)
Objectives
Understanding the cause of the blackout as well as the way the power system is built.
Modeling the fault occurring on the system using
Matlab/Simulink.
Understanding the different parameters within the power system that could have been altered to prevent the power outage.
Electrical
Power Pe
Load
Angle δ0
Stable Situation
Methods
The first step in this process was to model the Itaipu Dam, its transformers, transmission lines, and the rest of the Brazilian grid.
We first ran a reference test to determine the power output and load angle of the system under normal conditions.
The next test was to determine what would have happened, had the breakers on the transmission lines opened quickly enough.
The final test was to model the fault as it actually happened, in which the ageing breakers opened opened too slowly to prevent massive instability.
Electrical
Power Pe
Load
Angle δ0
Breaker time at 0.07s
Electrical
Power Pe
Load
Angle δ0
Breaker time at 0.21s
Analysis
Load angle refers to the lag (in degrees) between the rotating magnetic field, and the magnetic field of the stator. Too much variation in this angle causes instability in the generator.
When comparing the control test to the test with correct timings, the control is very stable and has very little variation after the initial surge. In contrast, the system that did not suffer from slow breakers experienced instability at the beginning, but stabilized as time went on.
The system representative of the actual blackout experienced sporadic instability at the time of the fault and continued to show instability throughout the simulation.
Conclusions
The data suggests that the massive fluctuations in power and load angle at the time of the blackout could have been controlled by faster breakers.
Load Angle δ ω PT Pe ωN δ0
SPONSORS: “This work was supported in part by the Engineering Research Center
Program of the National Science Foundation and the Department of Energy
under NSF Award Number EEC and the CURENT Industry Partnership
Program. "