Muhammad Irfan Jambak

Advanced laboratory scale model of high phase conversion power transmission line

Theory of high phase order conversion system i.e: six-phase transmission line has proved as an alternative to new line construction or voltage upgrading, the economic and technical viability of three to six phase conversion (termed high phase order conversion) of an existing double circuit line permitting about 73% more energy transmission without any change of the existing line tower, conductors and ROW area. Up to date there are many works done in this SPTL field reductions were only based on digital simulations and calculations. Tests on actual line settings and configuration which are needed during a study are challenges to researchers who have limited access to the lines. It will be more challenging especially reconfiguration exercises for HPO conversion of three phase to six phase system. This paper describes in the development of scaled down six phase transmission line (SPTL) model developed in the IVAT laboratory to serve the purpose of study of the steady state and transient behavior of high phase system.

Evaluation and mitigation of underground gas pipeline coating stress due to nearby lightning stroke

Rapid economic developments have forced power networks and pipeline networks to share the same pathway. Induced voltages and currents appear on pipelines running parallel with high voltage transmission line when the transmission line is hit by lightning strike. In this study, a simulation had been carried out to determine the first lightning stroke effect on an underground pipeline coating stress. CDEGS software was used to solve Maxwell equations; in particular, HIFREQ and FFTSES tools were utilized. A 2-km underground pipeline and a 345-kV transmission line (TL) tower had been modeled. A suitable TL-pipeline distance need to determined based on lightning current, surrounding soil properties, and coating withstand voltage. In addition, horizontal and vertical rods are able to reduce the overvoltage across the coating. The first layer soil resistivity and thickness are important factors to be considered when carrying out mitigation in a non-uniform soil.

AC breakdown strength performance of plasma treated mineral oil-based nanofluids

Nanofluids have been identified to be one of the suitable approaches to increase the breakdown strength of transformer oil. However, the nanofluids tend to form sediment which nullifies its full capabilities in increasing the electrical properties such as higher AC breakdown strength. In view of foregoing, this paper presents an approach to enhance the AC breakdown strength of the transformer oil by using plasma treated silica nanoparticles to form plasma treated nanofluids. The surface of silica nanoparticle was functionalized by using atmospheric pressure plasma discharge to enhance the interfacial interaction in order to improve the sedimentation issue in nanofluids. Plasma treated nanoparticles with desired surface functionality can strongly interact with liquid molecules with better dispersed into the base fluid to form a stable suspension. The AC breakdown strength of oil samples before and after surface modification of nanoparticles were measured accordance to IEC 60156 standard. Based on obtained results, it was found that the plasma treated nanofluids had higher AC breakdown voltage compared to the pure oil and the untreated nanofluids.

Evaluation of grounding system for AC substation using sub-ground (SG) software for novice professionals: Interpretation based on IEEE Std. 80-1986

Grounding system plays very important role in AC substation station for person and equipment safety. Proper design of grounding system is achievable by following IEEE Std-80 on safety in AC substation grounding but novice professionals find it not easy to use. The advantage of this paper presents evaluation of grounding system for AC substation by case studies presentation thus easing the understanding of IEEE Std-80 and its usage. This was carried out by using homegrown Sub-ground software with capability to identify the safety status of a grounding system design procedures. The grounding system is evaluated with six different cases. Different parameter is changed in each case to observe the result of the grounding system. The result shows that there are several important parameters in designing a grounding system. The parameters are grounding grid size, number of parallel rod, level of fault current, crush rock layer, cross sectional area of ground rod and level of soil resistivity. The tolerable and calculated step and touch voltage as well as the mesh voltage of the grounding system are presented in manner to tutor novice professionals on AC grounding system design. Last but not least the software developed in the laboratory useful for novice professionals training for AC substation grounding system.

Comparison of the effect of fixed metallic defects in coaxial gas insulated switchgear condition monitoring

Gas insulated switchgear assumes an indispensable equipment for high voltage transmission of electrical energy because of its focal points of high unwavering quality and execution, smaller in measurements and extraordinary compatibility with the environment. It utilizes sulphur hexafluoride gas as its insulant and coolant in view of its high dielectric quality and superb circular segment extinguishing capacity. Gas insulated switchgear in operation suffers the challenge of its insulation deterioration that leads to its failure due to the activities of partial discharge that is caused by defects. This failure is calamitous and it will prompt to whole power out stage that will affect all classes of human exercises. In order to monitor the condition of GIS, in this studies a simulated coaxial decomposition chamber was designed and used to simulate the decomposition of SF6 under the effect of fixed copper (Cu) and aluminium (Al) foil metallic artificial defect on the surface of the spacer in the chamber at the pressure of 0.2MPa when energizing with high voltage for a period of about 50 hours. The decomposition products of Cu and Al foil fixed defects detected offline by FTIR spectrometer are HF, SOF2, SOF4, SO2F2, SO2F10, SiF4, SO2, CO, C2F6, CF4 and SO2, SO2 F2, C3F8 and C2F6 respectively. These decomposed products and its concentration identify the type and the magnitude of fault in switchgear (contamination fault) and it shows that Cu fixed defect is more harmful to GIS than fixed Al foil defect.

Sulphur hexafluoride gas decomposition products of fixed metallic defect in coaxial gas insulated switchgear

A reliable diagnostic technique of Gas insulated switchgear condition monitoring is used in this research for the detection of Sulphur hexafluoride gas (SF6) decomposition products due to its high sensitivity and anti-electromagnetic interference; it is known as decomposition by-product method. A simulated coaxial decomposition chamber was designed and used to simulate the decomposition of SF6 under the effect of fixed metallic artificial defect on the surface of the spacer at the pressure of 0.2MPa when the chamber is energized at a 45KV experimental voltage over the period of 30 hours due to the presence of partial discharge caused by the artificial defect. The decomposition products (HF, SOF<inf>2</inf>, SOF<inf>4</inf>, SO<inf>2</inf>F<inf>2</inf>, SO<inf>2</inf>F<inf>10</inf>, SiF<inf>4</inf>, SO<inf>2</inf>, CO, C<inf>2</inf>F<inf>6</inf> and CF<inf>4</inf>) were detected offline by FTIR spectrometer. These decomposed products and its concentration can be used detect and identify the type and the level of fault in switchgear (contamination fault) before failure for purpose of preventive maintenance.

Atmospheric electric field measurement advances in Southern peninsular Malaysia

Lightning, which is also known as electrical charge separation in atmosphere, performs energetic discharge. By monitoring the atmospheric electric field (AEF), it helps to give precaution against the risk of lightning. The rotating electric field mill (REFM) is a sensor used in measuring AEF. REFM comprises of signal processing circuit (consists of amplification unit, filtering, conversion, and signal conditioning unit) for connection to data acquisition equipment in order to display, collect, and analyse the data. An investigation of different materials on REFM rotor and stator was performed to reveal their sensitivity and stability towards the high voltage atmosphere. The calibration results showed that aluminium sensor had been more suitable for AEF measurement compared to stainless steel sensor. The research purpose was to track the thundercloud development processes and movement. In addition, in order to investigate the characteristics of the signal from a thunderstorm cloud prior to cloud ground lightning discharges, the REFM was installed in UTM area. The data collected on-site revealed the characteristic signals of AEF in the atmosphere and the characteristics of the signal from a thunderstorm cloud prior to CG lightning discharges.