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This paper proposed the modelling and simulation of generator protection for power system using digital reverse power relay. The operations of the power plant are often interrupted by the reverse power generation. Therefore, generators need to be closely monitored and controlled. In this study, 11 kV synchronous generators are connected to 220 kV load through a step-up transformer, and a new model of reverse power relay is added for generator protection. The reverse power relay proposed in this paper is a digital relay with high accuracy and high reacting speed. Several cases based on various types of mechanical inputs to the generator were studied to test the operation of the reverse power relay. This simulation was done using MATLAB/Simulink. The results show that the 11 kV generator protection is successful with this new model reverse power relay. Besides, the simulation results were similar result compared to the theory result. From the simulation results, the integral output of the relay will reach the threshold value ‘L’ whenever there is a reversed power flow fault found in the system. Consequently, the relay will be triggered to provide protection for the generator. This model has been added into online resources of MATLAB Power System Tools. In addition, this model may also help the engineers to develop the analytical skills under various conditions.

The alternating current (AC) total interference of power lines may pose a threat to personnel and equipment in its vicinity. The main objective of this work is to determine the electromagnetic distribution and induced voltages on human body, equipment, and houses due to the AC total interference for different soil resistivities. The electromagnetic field and induced voltages may cause health problems to the human body and put it at risk. Two main approaches were used to compute the electromagnetic and induced voltages, namely the field approach, which is based on electromagnetic field distribution, and the circuit approach, which uses the circuit grounding analysis to compute the conductive interference and then uses the circuit based models to compute the inductive interference. Human body, steel houses and 10-km-long transmission line were modelled. The soil resistivity was varied, and the induced voltages obtained from both approaches were compared. Soil resistivity and soil structure are important parameters that affect the AC interference level. The results show that the touch voltage increases when the distance between electromagnetic source and human body increases. For high soil resistivity, the danger of the touch voltage becomes more prominent compared to that for low soil resistivity. Power system voltage level and soil resistivity are two key factors influencing the induced voltage level.

Sulphur hexafluoride (SFo) gas insulated switchgear (GIS) is widely used in electrical power supply system and therefore needs regular preventive maintenance. In this research work, a reliable and effective diagnostic technique was used to detect SFo byproducts caused by partial discharge (PD) occuring as a result of more that one defect, named as a hybrid defect. A 0.2-MPa presurrised coaxial chamber prototype similar to that used in GIS was used to simulate the decomposition of SFo when partially discharging at 48 kV. Two hybrid defects, namely a protrusion-floating particle and a void-floating, were used. The corresponding detected byproducts using Fourier transform infrared spectrometer are SO2, HF, SOF2, SO2F2, SO2F10, SiF4, CO, and C2F6 for the former, and C3F8 and C2F6 for the later. It was found that the by-product combination together with the by-product concentration can be correlated to the type of hybrid defect. Results also show that the protrusion-floating particle hybrid can be potentially more harmful than the void-floating hybrid.

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, SO 2 F 2 , SO 2 F 10 , SiF 4 , SO 2 , CO, C 2 F 6 , CF 4 and SO 2 , SO 2 F2, C 3 F 8 and C 2 F 6 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.

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 2 , SOF 4 , SO 2 F 2 , SO 2 F 10 , SiF 4 , SO 2 , CO, C 2 F 6 and CF 4 ) 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.

The stability of transmission lines relies on the health of the insulators, such as glass string insulators, which may occasionally flashover during an overvoltage. The likelihood of flashover increases notably when the glass insulator is wrapped by a wet contaminant layer. In this paper a study of the surface thermal profile of glass disc insulators insulation had been carried out for both clean and polluted surfaces. A finite-element simulation with time dependent model was carried out using COMSOL Multiphysics software. The variation of the insulator surface temperature with applied voltage as well as with pollution layer thickness is explained. The results illustrate the significant effect of pollution conductivity on heat propagate along the surface of the glass insulators with the increase higher voltages' magnitudes. Study of the aging level impact on a steady state thermal for glass insulation surface is also carried out.

Suitable diagnostic techniques for outdoor glass insulators are important for ensuring the reliablilty and stability of power system. The possibility of insulator flash-over increases, especially when the insulator is covered by pollution layers or has an internal defect. In this paper, a new technique to detect the pollution level and invisible damage by measuring the surface temperature of glass disc insulators is proposed. A high definition camera had been used to determine the surface temperatures of four glass insulators. The effects of applied voltage on the surface temperature and its distribution were studied. The results show the possibility of using the infrarad camera to detect the aging level and invisible damages of the glass insulators.

Electromagnetic pulses produced by lightning return strokes travel both above and underground for long distances. Lightning electromagnetic pulses are caused significant effects and disturbances on the function of nearby systems such as power, communications, and etcetera. Electromagnetic fields are propagate into both above and underground for long distances. This study purposes to increase the comprehensive about the effect of distance on the lightning electromagnetic propagation over frequency-dependent soil. The modified transmission line with exponential decay (MTLE) model is used to model the lightning return stroke channel. The return stroke, and electromagnetic propagation models were modeled using RF-Module in the form of finite elements analysis via COMSOL software. The studied electromagnetic components are radial electric field, vertical electric field and azimuthal magnetic field with various distance from lightning channel. Furthermore, their behaviors with different soil water content up to 100% were as well studied. Peak values, wave shapes, and polarities of the above/using frequency domain solvers under ground electric and magnetic fields are influenced by distance from lightning channel. The aboveground fields are differently affected by the soil water content for various distances. In contrast, the behaviors of soil water content of underground fields are non-significantly affected by the distance from lightning channel.

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.