Applied Mechanics and Materials Vol. 793

Abstract: This paper discusses the use of the intelligent microcontroller and also discusses the results from the simulation application of fuzzy logic theory to the control of the high voltage direct and alternation current (HVDC)& (HVAC) power station systems. The application considered their implementation in both low and high level control systems in HVDC& HVAC power station systems. The results for the fuzzy logic based controller shows many improvements compared to the conventional HVDC& HVAC control system. The fuzzy logic based controller concept was further successfully extended to high level control of optimization problems such as the power swings. Based on simulation results, HVDC and HVAC breaker design are online protection against unwanted incidents happening to the system.

Abstract: Grounding of electrical installation is primarily concerned with ensuring safety. The main purpose of grounding is to channel the fault current straightly to the earth. To produce a good grounding system, the value of earth resistance must be reduced as low as possible. Otherwise, current may flows through to those who touch the damage electrical equipment instead of flowing through grounding system. In this project, a 3 meter length of copper, galvanized iron and pure steel rod were installed in formatting of grounding system. The installation of the grounding rods was based on the fall of potential method. Both single rod testing and parallel rod testing were performed in this project. A comparison on grounding resistance value for copper rod, steel rod and galvanized iron rod was examined and the selection of the best grounding rod was determined from the experimental data. Result shows that different types of rod will produce different value of resistivity in which depend on installation technique and soil condition.

Abstract: Power system stability is the ability of an electric power system unit, for giving operating conditions beginning to recover operating state of equilibrium after being subjected to a physical interference. Power system stability has been recognized as an important problem for safe operation of system unit. Stability of power system is similar to the stability of any dynamic system, and has basic mathematical. Concepts from the mathematics and theoretical stability control are first revised to provide background information related to stability of dynamic system generally and establish a connection theoretical. This paper presents to improve of dynamic power system stability using frequency response as tuning of system stabilizer. It is started by electrical power systems mathematic modeling in state variable equation then set the expertise function of frequency response as tuning of system stabilizer. The plant controlled by function of frequency response is tuned to left half plane (LHP) as system stabilizer which their input from the rotor speed. When the system occur fault, the rotor speed should be synchronized, for this case one electrical controller is needed to make sure the system is stable.

Abstract: Examples of solid and liquid electrical insulations for power transformer are mineral oil and cellulose based paper. As transformers performed their function to step-up or step-down voltage level, its’ insulations will be degraded. Paper insulation is considered the most critical component in a transformer insulation system because it is not easily replaced if compared to oil where it is easily reconditioned in-order to remove water and contaminants. Studies show that temperature, moisture contents and oxygen contributed to paper insulation degradation. Moisture and furanic compound were produced from these deterioration processes. This paper is focused on the formation and effect of moisture to Kraft paper’s life. Levels of moisture contents were obtained from in-service power distribution transformers. These data then is used to assess the Kraft paper’s life by means of Weibull plot. This study shows that level of moisture contents can be used to assess the life of Kraft paper insulation.

Abstract: Recently, a new partial discharge location technique called three-point technique had been introduced to locate partial discharge on underground cable. It is the improvement of double-end technique. In this paper, the mathematical formula of three-point technique had been simplified from previous research. Alternative Transient Program (ATP) was being used to simulate both double-end and three-point technique. The results of the simulation were compared and analysed based on the accuracy, cost of implementation and algorithm complexity of the technique. Three-point technique had shown significant improvement in the accuracy of partial discharge location on underground cable.

Abstract: Electrical systems and devices suffer from unexpected failures due to various reasons such as input voltage fluctuation and low or high voltages. This paper discussedabout the development of a device for detecting imminent failure of electric products such as refrigerators, ovens, Air-conditions and etc. The main objective of this developed preventive device is todetect voltage drop or rise and produce an alarmsignal to enable and activates other protection circuitry.The mechanismof the detector/sensing circuit is based on differentiating the voltage level using dualcomparator; this makes the system more considerate. The method enables real-time monitoring of stability boundaries and the corresponding margin to the observed operating point, which is used to provide an early warning for emerging stability problems.

Abstract: Battery Energy Storage System (BESS) is one of the most popular and established options used to decouple the timing of generation and consumption of electric energy. In spite of variety types of energy storage exists, BESS has proven to be widely used in these three main energy applications, which are Renewable Energy (RE) integration, load leveling and peak shaving. Concurrently, managing stored energy and generated power is a real challenge where the load control system plays the decisive role to ensure better energy management efficiency with stabilized and guaranteed energy supply. This paper presents an analysis of various load control algorithms and methods used, integrated with BESS to achieve the required output. Besides that, recent research works are also summarized in this paper. Based on the study, battery State of Charge (SOC) is widely and mainly used in the load control algorithm and proven as effective and reliable load control strategy.

Abstract: Partial Discharge (PD) is one of a symptom in the underground cable before the fault happens.This paper concerned with estimation and detection problems related to PD phenomena in buried underground cables. The Rogowski coil has been implemented to analyze this symptom. The various sizes of nominal cross-sectional area cross-linked polyethylene (XLPE) cable with 6.35/11 KV single core unarmored aluminum conductors that follows Nexans manufacturer datasheet based on design standard IEC 60502 has been used in the simulation using Electromagnetic Transient Program-Alternative Transient Program (EMTP-ATP) software. The Lumped parameter is used for the Rogowski coil sensor model. Meanwhile, for Double-end measurement using J-Marti model is designed to evaluate the parameter changing in the measurement.Based on the measurement, the value of amplitude voltage and current is proportional increase depends on the size of cross-sectional area of conductor XLPE cable.

Abstract: Generally this project is to improve the dynamic power system stability using fuzzy logic power system stabilizer (FLPSS) which applied to the excitation system. This research is started by electric power system mathematic modelling (state variable equation) and block diagram then set membership function of fuzzy logic power system stabilizer (FLPSS). Block diagram model (plant system) is formed from state variable equation. The plant is controlled by fuzzy logic power system stabilizer (FLPSS) which its input and output from the rotor speed and to excitation system, respectively. To observe the oscillation of dynamic power system stability, the electrical power is varied ± 0.1 pu (positive and negative value indicate an increasing and decreasing electrical power, respectively). The result shows that using FLPSS, the oscillation of dynamic power system can be improved. The overshoot of electric power and rotor speed change oscillation after the disturbance is smaller than the conventional, and also the time to reach the steady state is faster.

Abstract: Distribution transformer in Malaysian electricity network is categorized as major element on delivering electricity throughout the nation. Advanced diagnostic tools are used to monitor any technical problem of transformer to sustain its capability in the long run. One type of it which is currently being used in worldwide is Frequency Response Analysis (FRA). The reliability from this method is proven worldwide in diagnosing transformer condition especially a mechanical movement. FRA technique is done by comparing the response result in transformer initial condition to its current condition. The interpretation of transformer condition from the response is based on frequency sub-bands. Each frequency sub-bands are indicating any movement parts of transformer and electrical faults. Currently, there are three worldwide standards established for interpreting the FRA results but both of them are different in frequency sub-bands range. Up to now, there are no research papers comparing the fault detection capabilities from frequency sub-bands range for both standards. In this paper, comparative study is done to visualize and interpret the capabilities from three standards (IEEE Std C57.149 2012, DL/T911-2004 and Cigre WG A2/26); by focus on the frequency sub-bands range.