Influence of Ev on Grid Power Quality and Optimizing the Charging Schedule to Mitigate Voltage Imbalance and Reduce Power Loss

EE524 Transient Analysis In Power System

Final Project

Anchen Li

USC-ID: 2950996947

Email: anchenli@usc.edu

1. Introduction        

An electrical transient is the outward manifestation of a sudden change in circuit conditions, as when a switch opens or closes or a fault occurs on a system. These transient periods are extremely important, for it is at such times that the circuit components are subjected to the greatest stresses from excessive currents or voltages. In extreme cases damage results, this may disable a machine, shut down a plant, or black out a city, depending upon the circuit involved. In this great course EE524, we start to learn how it varies and what we can do to reduce the risk. Now, we come to a project using the EMTP, wish to find what is going on in the transient time.

2. Objective        

From this project, I want to study what the electrical transients will be when we open or close the switch in a power system. With the help of EMTP, I want to clearly see the voltage and current’s changing of the devices.  

3. Circuit        Schematics        

In this project, I choose the following power system to do the analysis.

[pic 1]

The upper graph shows a small power system. There are five buses and two generators in it.

[pic 2]

This figure shows the circuits I draw in the EMTP. I use “π” model to simulate the transmission line. All the data are based on the book.

4. Circuit        Data

The following figure shows all the parameters of the power system. This is a practical circuit, so we can easily get the analysis data which is close to the reality.

[pic 3]

5. Modeling        and        Testing

• Test 1:

Let’s make the switch 4 open initially, then at 10ms, the switch 4 turns to closed and keep at that state.

[pic 4]

For all other switches, we make them closed from beginning to end like the following figure shows.

[pic 5]

• Test 2:

This time, we set the switch 4 closed initially and then, at 10ms later, we make it open.