1. Fault Analysis in HVDC Systems Using Signal Processing Techniques
Benish Paily
School of Electrical and Electronic Engineering
You Supervisors’ Names Here
Dr. Malabika Basu
Dr. Michael Conlon
29th November, 2013

2. Presentation Overview1
HVDC - Next Dimension 2
HVDC Projects 3
Fault Analysis of HVDC System

3. HVDC-Next Dimension 1954 1980 FUTURE Current Link HVDC System
LCC HVDC
1954
VSC HVDC
1980
MULTITERMINAL HVDC
FUTURE
Current Link HVDC System
Voltage Link HVDC System
Total 200,000MW HVDC Transmission
Capacity in operation or under construction
170 Projects around the world
ABB: 90 Projects, 120,000MW
HVDC Light Technology
Siemens: HVDC Plus Technology

4. HVDC Projects HVDC Projects in Europe (ABB)
East West Interconnector (HVDC Light)2013, connecting Ireland and Wales
Link between Ireland and Wales
Power rating: 500MW
AC Voltage: 400 kV
DC Voltage:± 200kV
DC Underground cable: 2*75 km
DC Submarine cable: 2*186 km

5. Fault Analysis of HVDC Systems
HVDC system subjected to
DC Line Fault
HVDC system subjected to
AC line fault at Rectifier & Inverter side
Single line to ground fault (SLG)
Line to line fault (LL)
Double line to ground fault (DLG)
Triple line to fault (3L)
Line to ground fault
Line to line fault

6. Faults in HVDC System AC Faults DC Faults
DC Current increases to 2.2 p.u.
AC Faults
DC Current
DC Voltage
DC Voltage falls to zero at the rectifier

7. Fault Identification in HVDC System
abc to dq0 transformation
Computes the direct axis, quadratic axis and zero sequence quantities in a two-axis rotating reference frame for a three-phase sinusoidal signal
Known as Park transformation

8. abc to dq0 transform in DC and AC fault of HVDC
Peak Magnitude of DQ under DC faults
Parameter
Distance (km)
DQ magnitude
Normal Operation
12.38
DC Fault 50
26.58
100
27.48
150
28.09
200
28.18
250
28.40

9. abc to dq0 transform (conti.)
Peak Magnitude of DQ values under AC faults at Rectifier side
AC Faults at Rectifier side
Peak Magnitude of dq in unit
No Fault
12.38
Single line to ground fault
99.23
Line to line fault
150.60
Double line to ground fault
144.96
Triple line to ground fault
223.18

10. Wavelet Transform Mathematical Technique
2. Analysing signals simultaneously in time and frequency

11. Wavelet transform in DC and AC fault of HVDC
DC faults at
150 km, 250 km
Absolute maximum value of five levels wavelet coefficients of dc line current for dc fault at various fault distances
DC Fault
Normal
Operation
50 km
100 km
150
200
250 Km
Max. value of
wavelet
coefficients in five level
0.09
0.18
0.28
0.67
0.78
0.83

12. Wavelet transform (cont.)
SLG and LL
Fault
Absolute maximum value of five levels wavelet coefficients of dc current for various ac fault at rectifier side
AC Fault at
Rectifier side
Normal Operation
SLG LL
DLG
LLL
Maximum coefficients
0.09
0.35
0.43
0.25
0.41

13. Conclusions
1. Fault Identification in HVDC system is a challenging process because it should be accurate and fast
2. abc to dq0 and wavelet transform can be applied to fault identification
3. In fault identification abc to dq0 transform performed very well but the accuracy of fault distance estimation was poor.
4. Wavelet transform is considered as a powerful signal processing tool for transient analysis of signal
5. Wavelet transformation effectively proved that it can detect the abrupt changes of the signal indicative of a fault.

14. Thank you