Abdulrehman Ali Al-Arainy

Grounding Pit Optimization Using Low Resistivity Materials for Applications in High Resistivity Soils

Grounding arrangement is very important to maintain safe and reliable operation of a power system and to ensure safety of the power apparatus and operating personnel. In Saudi Arabia, the weather is dry and the soil resistivity varies significantly from area to area because the geodetic terrain varies from sea shore to the arid desert and dry mountains. In most of the inland desert areas, the soil resistivity is significantly high and it is difficult to get low earth resistance with conventional methods. Therefore, an economical and efficient grounding system design of the earthing pit is necessary which can be achieved by using a low resistivity material (LRM). When such material is used, it is important to optimize the pit design. This paper presents different configurations of grounding pits commonly used with LRM applications. Different parameters that affect the grounding resistance are studied in detail and an optimized pit design is suggested that can effectively reduce the grounding resistance to an acceptable value. The suggested method can be readily used by engineers to obtain a good earthing pit configuration for efficient grounding of the power system components in high resistivity soils.

Loss and Recovery of Hydrophobicity of EPDM Insulators in Simulated Arid Desert Environment

Electrical insulators form a very important component of high voltage electric power networks. Along with the traditional insulators i.e. glass and porcelain, etc. presently the polymeric insulators are also used world widely. These polymeric insulators are very sensitive to various environmental parameters such temperature, environmental pollution, UV-radiations, etc. which seriously effect their electrical, chemical and hydrophobic properties. The UV radiation level in the central region of Saudi Arabia is high as compared to the IEC standard for the accelerated aging of the composite insulators. Commonly used suspension type of composite EPDM (ethylene propylene diene monomer) insulator was subjected to accelerated stress aging as per modified IEC standard simulating the inland arid deserts atmospheric condition and also as per IEC-61109 standard. The hydrophobic characteristics were studied by measuring the contact angle along the insulator surface before and after the accelerated aging of the samples. It was found that EPDM insulator loses it hydrophobic properties more proportional to the intensity of UV radiations and its rate of recovery is very low as compared to Silicone Rubber insulator. The effect of water salinity and drop size on the contact angle characteristics was also investigated.

Environmental friendly power dispatch in Saudi Arabia with renewable energy and energy storage

Optimization of the total amount of pollutants emitted from the hybrid power plants is the main objective of the Environmental Friendly Dispatch (EFD). The EFD problem decides the amount of generation to be allocated to each generating unit including renewable sources so that the total emission of polluting gases is minimized without violating the system constraints. This type of optimization becomes more efficient in countries like Saudi Arabia where high potential of crude oil and renewable resources exists. This paper considers the problem of EFD for hybrid power system including solar, wind and the storage. High potential of solar and wind in Saudi Arabia ensures the availability of renewable sources to some extent. A consistent optimum EFD can be obtained by extracting maximum renewable energy during the available period and using it for both available and unavailable periods with the aid of energy storage. This paper illustrates the optimization of EFD with renewable storage using MATLAB simulation. The simulations have been done using IEEE-30 test bus data with 6 generators.

A review of condition monitoring of underground power cables

Power distribution system relies heavily on a vast network of medium voltage (MV) underground cables for power delivery. Condition monitoring technologies can, therefore, play a vital role in attempting to target the cables that pose the most urgent reliability concerns. Maintaining or increasing a power systems reliability at minimal cost is an important issue for most network owners. Condition monitoring gives the information needed for safe and reliable operation, replacement strategy and hence increases the system reliability. Demands for reliable power causes a growing tendency to apply different strategies in the form of condition based maintenance. Partial discharge (PD) monitoring is one of the successful diagnostic tools for accessing the insulation condition of MV cables. Data acquired by online PD measurements can help in identifying the upcoming faults in such cable networks and possibly forecast the remaining life of the insulation. This paper reviews the condition monitoring and diagnostic techniques used for underground power cables.

Investigation of attenuation characteristics of PD pulse during propagation in XLPE cable

Wave propagation characteristics of partial discharge (PD) pulses in underground medium voltage cables are important when online PD monitoring system is implemented for cable diagnostics and condition assessment. There are three important parameters that can influence the wave propagation characteristics along a cable. These are the length of the cable, cable loading conditions and propagation characteristics of the cable. Propagation losses occur in power cables as PD pulses propagate along the cable. Since different types of cables have different parameters, the wave propagation characteristics such as attenuation and propagation speed will also vary accordingly. This paper presents the results of an experimental study performed to investigate the attenuation behavior of PD pulses as they propagate along a medium voltage XLPE cable and undergo reflections. It is shown that PD pulses attenuate as these propagate and higher frequency components suffer more in attenuation. This in turn decreases the magnitude and increases rise and fall time of pulses.

HYDROPHOBIC CHARACTERISTICS OF COMPOSITE INSULATORS IN SIMULATED INLAND ARID DESERT ENVIRONMENT

Presently along with traditional insulators i.e. glass and porcelain, etc., the polymeric insulators are also used world widely. These polymeric insulators are very sensitive to various environmental parameters e.g. UV radiations, heat, etc. The UV radiation level in the central region of Saudi Arabia is high as compared to the recommended IEC‐61109 standard for the accelerated aging of the composite insulators. In this study, thermoplastic elastomer (TPE) and Ethylene Propylene Diene Monomer (EPDM) insulators were subjected to accelerated aging stress as per IEC standard as well as modified IEC standard simulating the inland arid desert’s atmospheric conditions. The hydrophobic characteristics were studied by measuring the contact angle along the insulator surface before and after the accelerated aging of the samples. It was found that TPE loses its hydrophobic properties more as compared to EPDM insulator. This loss was proportional to the intensity of UV irradiation. The rate of recovery is also low fo...