On-line diagnostics of high voltage power components by utilising naturally occurring transients

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Project abstract

The key question to be addressed in this project is how one can use naturally occurring transients to diagnose the status of electric power equipment, and in particular the status of the electrical insulation.

Two concepts will be treated:

1) The linear response of the power component and in particular the dielectric response of the insulation system. The main task is to identify how one can measure certain characteristics of the insulation from the stimulus of different transients of different amplitude and bandwidth, i.e. typically overvoltages of lightning, switching and temporarily nature and long-time duration.

2) The non-linear nature of defects that in-particular may start to generate partial discharges (PD) after a transient. The behaviour and progression of the PD activity before, during and after a transient situation.

Summary of work

2015. The focus of the second part of the project (2015 and 2016) was on progression of the PD activity before, during and after a transient is undergoing. Interesting results have been obtained about the effect of transients on the surface discharge characteristics of oil-paper and polyethylene. To perform the measurements in the same condition as in the field, a system to generate AC with superimposed impulse has been arranged. The interpretation of results can be helpful in diagnostics and health checking of power components.

Life-time estimation of the component based on the natural transient stresses is another topic that has been worked on. Suitable models have been investigated to predict the remaining life time of the components insulation.

2015. The visit to University of Utah was spent with a group that uses diagnostic measurement data as an input for system reliability studies. This period was educational as a complement to the laboratory studies that have been the focus of the rest of the project.

2016. On return to KTH, the remaining months of the project were spent using the laboratory setup for PD measurements under combined ac and impulse voltage, that was developed in 2015. The changes of AC PD activity around the time of a voltage impulse were studied in detail for normal transformer papers with AC voltage below and above PD inception and with varied moisture content, with surface and cavity PD. Another study of surface PD was made comparing special paper samples including ones with nanoparticles and varied lignin content. Two journal papers have been written on this subject, one of which is already accepted for publication in IEEE TDEI.

2016. A further study was made of dielectric response measurements using impulse voltages as the stimulus: in contrast to earlier work, the measurement used HV impulse and was performed with the AC source also active, as a proof of concept of dielectric response measurements on a real transformer bushing with online voltage conditions, although performed in the lab. This work has been accepted for publication in IEEE TDEI.

2016. In June 2016 the PhD thesis was presented.

Event log

2012. Diploma for Young Scientists, International Conference on Lightning Protection, ICLP 2012 Vienna, Austria

2013. SweGRIDS conference Best Poster award, Stockholm, Sweden

2013. Young Researcher Award, 18th International Symposium on High Voltage Engineering, ISH 2013, Seoul, Korea

2015. Roya had a 4-month visit at University of Utah at the end of this year, to study more about equipment reliability modelling. This was a "mobility" within the KIC InnoEnergy PhD school.

2016. Student Excellence Award (of High Voltage Association), at the 2016 IEEE International Power Modulator and High Voltage Conference (2016 IPMHVC) in San Francisco. The inscription is "For outstanding contributions in the field of Dielectrics, Insulation, and Breakdown - Effect of High Voltage Impulses on Partial Discharge Characteristics of oil-Impregnated Paper for Online Diagnostics".

Project reference-group

Tord Bengtsson,  ABB
Hans Edin,  KTH
Nathaniel Taylor,  KTH

Publications by this researcher

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Non-parametric Regression Model for Continuous-time Day Ahead Load Forecasting with Bernstein Polynomial
Roya Nikjoo,   A. Estebsari,   Mohammad Nazari.
2019,   19th IEEE International Conference on Environment and Electrical Engineering and 2019 IEEE Industrial and Commercial Power Systems Europe, EEEIC/I and CPS Europe 2019

Dynamic Resistance Measurements and Result Interpretation for Various On-Load Tap Changers
Alexandar Boricic,   Danilo Laban,   Bruno Moedim,   Almudena Conde Lopez,   Benjamin Molinari,   Zain Riaz,   Roya Nikjoo.
2019,   2019 IEEE Milan PowerTech, PowerTech 2019

Dielectric response measurement by impulse stimulus on AC : Measurement considerations, and laboratory testing on a bushing
Roya Nikjoo,   Nathaniel Taylor,   Hans Edin.
2017,   IEEE transactions on dielectrics and electrical insulation, vol. 24(1)

Dielectric Response and Partial Discharge Diagnostics of Insulation Systems by Utilizing High Voltage Impulses
Roya Nikjoo.
2016,   Thesis (PhD), KTH Royal Institute of Technology, TRITA-EE 2016:080

Effect of superimposed impulses on AC partial discharge characteristics of oil-impregnated paper
Roya Nikjoo,   Nathaniel Taylor,   Hans Edin.
2016,   IEEE transactions on dielectrics and electrical insulation, vol. 23(6)

Effect of High Voltage Impulses on Partial Discharge Characteristics of Oil-Impregnated Paper for Online Diagnostics
Roya Nikjoo,   Nathaniel Taylor,   Hans Edin.
2016,   IEEE International Power Modulator and High Voltage Conference (IPMHVC), San Francisco, 8 Jul 2016

Effect of High Voltage Impulses on Surface Discharge Characteristics of Polyethylene
Roya Nikjoo,   Nathaniel Taylor,   Hans Edin.
2015,   Nordic Insulation Symposium (Nord-IS)

Insulation condition assessment of power transformer bushings by utilizing high voltage lightning impulses
Roya Nikjoo,   Nathaniel Taylor,   Hans Edin.
2015,   IEEE Eindhoven PowerTech, PowerTech 2015, 29 June 2015 through 2 July 2015

The effect of PD by-products on the dielectric frequency response of oil-paper insulation comprising of a small cavity
Respicius Clemence Kiiza,   Mohamad Ghaffarian Niasar,   Roya Nikjoo,   Xiaolei Wang,   Hans Edin.
2015,   IEEE transactions on dielectrics and electrical insulation, vol. 22(5)

Dielectric Response of Oil-impregnated Paper by Utilizing Lightning and SwitchingTransients
Roya Nikjoo,   Nathaniel Taylor,   Respicius Clemence Kiiza,   Hans Edin.
2015,   IEEE transactions on dielectrics and electrical insulation, vol. 22(1)

Effect of High Voltage Transients on Surface Discharge Characteristics of Oil-Paper Insulation
Roya Nikjoo,   Nathaniel Taylor,   Hans Edin.
2015,   33rd IEEE Electrical Insulation Conference (EIC), JUN 07-10, 2015, Seattle, WA

Diagnostics of Oil-Impregnated Paper Insulation Systems by Utilizing Lightning and Switching Transients
Roya Nikjoo.
2014,   Thesis (Licentiate), KTH Royal Institute of Technology, TRITA-EE 2014:018

Change in Partial Discharge Activity as Related to Degradation Level in Oil-Impregnated Paper Insulation : Effect of High Voltage Impulses
Respicius Clemence Kiiza,   Mohamad Ghaffarian Niasar,   Roya Nikjoo,   Xiaolei Wang,   Hans Edin.
2014,   IEEE transactions on dielectrics and electrical insulation, vol. 21(3)

Dielectric Response of Aged Transformer Bushings Utilizing Power System Transients
Roya Nikjoo,   Nathaniel Taylor,   Respicius Clemence Kiiza,   Hans Edin.
2013,   2013 4th IEEE/PES Innovative Smart Grid Technologies Europe, ISGT Europe 2013

Effect of Dielectric Material on Decay of Surface Charge Deposited by Corona Discharge
Xiaolei Wang,   Respicius Clemence Kiiza,   Mohamad Ghaffarian Niasar,   Roya Nikjoo,   Nathaniel Taylor,   Hans Edin.
2013,   18th International Symposium on High Voltage Engineering (ISH), 2013 Korea

Insulation Condition Diagnostics of Oil-impregnated Paper by Utilizing Power System Transients
Roya Nikjoo,   Nathaniel Taylor,   Respicius Clemence Kiiza,   Hans Edin,   Mohamad Ghaffarian,   Xiaolei Wang.
2013,   18th International Symposium on High Voltage Engineering

Effect of High Voltage Impulses on Surface Discharge at the Oil-Paper Interface
Respicius Clemence Kiiza,   Mohamad Ghaffarian Niasar,   Roya Nikjoo,   Xiaolei Wang,   Hans Edin.
2013,   Nordic Insulation Symposium (NORD-IS)

Effect of high voltage impulses on partial discharge activity in a cavity embedded in paper insulation
Respicius Clemence Kiiza,   Roya Nikjoo,   Mohamad Ghaffarian Niasar,   Xiaolei Wang,   Hans Edin.
2012,   2012 IEEE Conference on Electrical Insulation and Dielectric Phenomena, CEIDP 2012

Comparison of phase resolved partial discharge patterns in small test samples, bushing specimen and aged transformer bushing
Respicius Clemence Kiiza,   Mohamad Ghaffarian Niasar,   Roya Nikjoo,   Xiaolei Wang,   Hans Edin,   Z. Ahmed.
2012,   2012 IEEE Conference on Electrical Insulation and Dielectric Phenomena, CEIDP 2012

Dielectric response measurement of power transformer bushing by utilizing high voltage transients
Roya Nikjoo,   Nathaniel Taylor,   Mohamad Ghaffarian Niasar,   Hans Edin.
2012,   2012 IEEE Conference on Electrical Insulation and Dielectric Phenomena, CEIDP 2012, 14 October 2012 through 17 October 2012, Montreal, QC

Changes in phase resolved partial discharge patterns in a cavity embedded in paper insulation due to AC voltages andhigh voltage impulses
Respicius Clemence Kiiza,   Roya Nikjoo,   Hans Edin.
2012,   proceedings 10th NORDAC 2012, Espoom Fubdabdm 10-11 Septenber 2012

Effect of transformer winding on the transient response of power transformer bushings
Roya Nikjoo,   Hans Edin.
2012,   2012 31st International Conference on Lightning Protection, ICLP 2012, 2 September 2012 through 7 September 2012, Vienna

Effect of temperature on surface discharge in oil
Mohamad Ghaffarian Niasar,   Respicius Clemence Kiiza,   Xiaolei Wang,   Roya Nikjoo,   Hans Edin.
2012,   2012 IEEE Conference on Electrical Insulation and Dielectric Phenomena, CEIDP 2012

Publication list last updated from DiVA on 2024-08-22 22:56.

Page started: 2011-12-01
Last generated: 2024-08-22