UWE Bristol Engineering showcase 2015

Phan Giang Thai Ngoc
BENG (HONS) ELECTRICAL AND ELECTRONIC ENGINEERING
Project Supervisor
DR. HASSAN NOURI
Investigation into impact of pre-insertion resistors in Circuit breakers
Modelling representation and concept
Once when in use (open / close), switch time break causing
impacts to the circuit, called the overvoltage. The
methodology of analyzing the effects of the pre-insertion
resistor and pre-insertion inductor on the 138 KV
transmission line was modelled and simulated using PSCAD.
The full model of the transmission line circuit with bus line
and all component in PSCAD shown in the figure.
Result:
In this study, the 138 KV transmission line with break
time switch is built in PSCAD. The pre-insertion
impedance is considered in this project. The different
value of components are changed in many case. The
result in PSCAD is shown that:
I. Overvoltage in circuit which has break time switch
II. Uncontrolled overvoltage in transmission line
III. Controlled overvoltage in transmission line
I. Pre-insertion resistors
II. Pre-insertion inductor
IV. Comparison
Project summary
This project present the analyzing of pre-insertion
impedance in a 138V transmission line using
PSCAD/EMTDC. 50 ohm resistors and inductors 20mh
turn is inserted into the circuit. Overvoltage will be
measured at remote bus and capacitor bus what call
phase to phase overvoltage and ground to phase
overvoltage. A comparison is shown to see the best
method for different cases.
Project Objectives
• PSCAD Familiarization
• Understand the 1-phase circuit.
• Understand the 3-phase circuit
• Understand the circuit with break time
switch
• Understand the transmission line
• Analyzing the waves voltage in
uncontrolled and controlled voltage.
• This project will study the analyzing and
the comparison the voltage in circuit.
The complete line model consists of several
sub model representing the following
elements:
1. Transmission line and circuit components.
2. Break time switch are installed the closed
function.
3. Pre-insertion resistors and pre-insertion
inductor with different values
4. Voltage wave table.
Ground to phase uncontrolled overvoltage wave
Ground to phase pre-insertion resistor overvoltage
wave
Project Conclusion
Over 3 study optimal control circuit voltage of
transmission lines with break time switch.
Three ways are: fixed inductor, pre-insertion
resistor and inductor pre-insertion. Each
method has its own advantages and
disadvantages. Finally, pre-insertion inductor
is chosen as the most complete method to be
used.
Phase to phase pre-insertion resistor overvoltage
wave
Pre-insertion inductors.