Performance Analysis of PWM Based Full Wave Bridge Inverter

An obvious device for the utilization of renewable energy sources is inverter and Pulse Width Modulation technique is widely used method for voltage source inverters. This paper deals with the generation of PWM signals by analog circuit, where the comparison of sine wave and sawtooth wave for the operation of power circuit takes place. The above mentioned technique is studied and verified by Simulating the circuit. The prototype of PWM based, single phase, full bridge inverter is developed and the results are verified for the nominal voltage and frequency with the help of simulation and hardware is designed. Keywords: Inverter, SPWM, VSI, Simulation, MATLAB

Reducing Power Losses by Voltage Stabilization at the DC Rolling Stock Current Collector

The invention relates to an energy-efficient method for voltage stabilization at the electric rolling stock current collector through traction substation control means which provide a nominal voltage value during the electric train movement by an interstation section. The dependence of potential distribution in the contact wire during the electric rolling stock movement by an interstation section was investigated. Also researched and developed are the new ways of voltage stabilization at the current collector of the electric rolling stock based on synchronous (the same for two adjacent traction substations) and asynchronous paths of voltage regulation at DC buses of traction substations related to one synchronous and two asynchronous ways of voltage stabilization in the contact network with obtaining the energy performance describing them. The energy performance of the investigated methods of voltage stabilization in the contact network is compared, and the energy efficiency of each of them is determined. It is proved that the use of modern types of semiconductor converters such as an active rectifier – voltage source in the power equipment of DC traction substations will enable to implement adaptive voltage stabilization systems at the rolling stock current collector, providing nominal voltage values of traction motors on the interstation section without using additional equipment on the rolling stock and, as a consequence, justification and application of these methods is suitable for upgrading the existing and designing new traction substations.

Estimation of stator and rotor forms distortions influence on operating parameters of a hydrogenerator

The field calculation was carried out using finite element method of the Ansys Maxwell software package and verification in the Matlab Simulink software. It should be noted that there are several regulatory documents that describe criteria for permissible distortion of the rotor shape, where the air gap between the stator and the rotor at diametrically opposite points should not differ from each other by more than ± 20% from the average value equal to their halfsum. In this work, a calculation was carried out covering this interval of diameter change; an analysis was carried out considering change in range of ± 35% of the air gap’s width’s value. Results of the research showed that a change in a value of the air gap up to 10% would make a significant contribution to magnitude of magnetic field induction, which increases the value of main losses in a core of magnetic circuit of the generator. Also, there is a significant decrease in voltage (from 25 to 50%) of a nominal voltage in nominal power mode, which requires increase in current in field magnetizing coil, leading to ohmic losses’ increase in rotor’s windings.

14-bit ADC as voltage monitoring device for power supply module 6 using I2C interface

<p>Thereare recorded downtime in the current testing processes of microelectronic packages. The available test equipment, the isolation of the power supply modules and the processes of testing must be changed in order to minimize the downtime. This study presents the design and development of a voltage monitoring device made of a 14-bit analog to digital converter (ADC) interfaced through inter-integrated circuit (I2C) for power supply module 6 (PS6). It is built to address the downtime in isolation and testing process of PS6. This setup is able to monitor and display three output voltages operating in 4-12V signals through athin film transistor (TFT) monitor. Tests were conducted for the nominal voltage and current setting scalled the three-point tests. In result, the fault detection and calibration process of PS6 are able to minimize downtimes. The developed voltage monitoring device has an acceptable percentage of 0.04572% which also canbe a replacement for digital multimeters (DMMs) for specific applications to PS6.</p>

Simulasi ETAP untuk Evaluasi Proteksi Gangguan Tegangan Lebih Generator Unit 3 PLTP Kamojang

AbstrakPada penelitian ini dilakukan evaluasi proteksi gangguan tegangan lebih pada generator Unit 3 PLTP Kamojang yang diproteksi oleh sebuah relay tegangan lebih menggunakan simulasi pada software ETAP. Simulasi dilakukan untuk melihat bagaimana cara kerja relay tegangan lebih dan bentuk tegangan lebih yang terjadi pada terminal generator. Skenario simulasi yang digunakan yaitu melakukan pelepasan beban 50,7 MW dan relay yang digunakan dalam simulasi berfungsi untuk menyalakan alarm saat terjadi tegangan lebih. Hasil simulasi memperlihatkan bahwa pada saat terjadi pelepasan beban, relay tegangan lebih menyalakan alarm 1,1 detik setelah membaca tegangan naik hingga 13 kV atau sebesar 110% dari tegangan nominalnya, kemudian tegangan terminal generator naik hingga 13,2 kV hingga kembali ke kondisi steady state 5 detik setelah terjadi kenaikkan tegangan. Hasil simulasi tersebut menunjukkan bahwa relay tegangan lebih yang terpasang pada terminal generator Unit 3 bekerja sesuai dengan fungsinya yaitu untuk memberikan alarm ketika tegangan lebih terjadi.Kata kunci: pelepasan beban, proteksi generator, relay proteksi, simulasi generator, tegangan lebihAbstractThis study evaluates overvoltage fault protection on the generator Unit 3 PLTP Kamojang which is protected by an overvoltage relay using simulation on ETAP software. Simulations are carried out to see how the overvoltage relay works and the form of overvoltage that occurs at the generator terminals. The scenario used is by do a load shedding of 53,3MW, the relay used in this simulation has a function to turn on the alarm when overvoltage occurs. The results show that when a load shedding occurs, the overvoltage relay turns on the alarm 1,1 seconds after reading the voltage up to 13 kV or 110% of the nominal voltage, then the generator terminal voltage rises to 13.2 kV until it returns to steady state 5 seconds after the voltage increase. The simulation results indicate that the overvoltage relay installed at the generator terminal Unit 3 works according to its function, namely to provide a warning when an overvoltage occurs.Keywords: generator protection, load shedding, overvoltage, protection relay, generator simulation

Principles of electrical grid configuration management and tasks of their implementation

THE PURPOSE. To consider and analyze the definitions of the concepts "configuration of the electrical grid", "control of the configuration of the electrical grid ", "parameters of the configuration of the electrical grid ". To justify the need to manage the configuration of electrical grid, describe the principles and methods of managing the configuration of the electrical grid. To demonstrate the implementation of the principles of managing the configuration of the electrical grid on the example of an electrical grid with a nominal voltage of 0.4 kV with the use of proprietary technical configuration management tools. METHODS. Based on the literature review, the study identified the wording of key concepts, such as" configuration of the electrical grid"," management of the electrical grid configuration", "parameters of the electrical grid configuration". Methods of managing the configuration of the electrical grid are shown. The principles of electrical grid configuration management proposed by the authors are considered, which include observability, manageability, segmentability, flexibility of the electrical grid configuration, equipment intellectualization, and integration into the economy. The essence of each of the management principles is revealed and the effects of their implementation are shown. The effects of implementing the configuration management principles are to reduce the number of power supply interruptions and reduce the time of power supply interruptions to consumers, mismatch the quality parameters of the electricity supplied to them, as well as to increase the availability of electricity infrastructure. The rationale for the need to manage the configuration of electrical grid is given. Within the framework of the conducted research, the method of system analysis, methods of comparisons and analogies, and expert assessments were used. RESULTS. On the example of the scheme of power supply to consumers at a voltage of 0.4 kV, the implementation of the principles of control of the configuration of electrical grid with the use of proprietary technical means – multi-contact switching systems, input-accounting-distribution devices integrated into the monitoring systems of the parameters of the operating modes of electrical grid and other devices is illustrated. CONCLUSION. The implementation of the principles of configuration management of electrical grid allows to increase the efficiency of power supply systems for consumers and at the same time causes the need to develop new technical means of automation and monitoring of parameters of operating modes of electrical grids.

A Comparison of Batteries for the MECS Project

In the context of the MECS project, the batteries are required to operate cooking appliances. In off-grid applications they are needed to store solar PV electricity. In weak-grid or mini-grid applications, batteries are needed to store electricity for later use, when grid electricity is more expensive, insufficiently powerful, or unavailable.All the batteries tested have a nominal capacity of 100Ah and a nominal voltage of 12V. In the case of lead-carbon, a single 100Ah battery was used. In the case of VRLA and LiFePO4, two 50Ah batteries of each were used to make a total of 100Ah when connected in parallel. Of the three battery chemistries tested, the lithium-iron-phosphate (LiFePO4) is clearly superior to the lead-acid and lead-carbon. It maintains a higher open-circuit voltage and can deliver much more energy at high power.

Analisis Pengaruh Sudut Penyalaan TRIAC terhadap Pengaturan Kecepatan Motor Induksi Satu Fasa Menggunakan Cycloconverter

ABSTRACTA single-phase induction motor is one type of electric motor that is most widely used in everyday’s life, especially for running small loads. The application of this single phase induction motor is not only in households but also in shops, shopping centers, and industry. In its operation, single-phase induction motors can be operated with constant speed and variable speed. The operation of a single-phase induction motor at a constant speed can be done by inputting the nominal voltage and frequency of the motor. Meanwhile, the operation of a single-phase induction motor with varying speeds can be done by adjusting the input frequency of the motor. In this study, an induction motor speed control was carried out using a cycloconverter to regulate the speed of a single-phase induction motor by changing the input frequency of the motor into three variations, namely f / 1, f / 2 and f / 3 at the base frequency of 50 Hz. The cycloconverter switching was designed using TRIAC and then a study was carried out on the effect of the TRIAC’s firing angle on the speed, voltage and output power of the motor by varying firing angles by 0?, 30?, 45?, 60? and 90?. The result show, it is found that increasing the firing angle, the motor output voltage decrease, the motor output power also decrease, except at the angle of 60 ? rises then at the angle of 90 decrease again, while the motor speed increases at the same frequency. Keyword: cycloconverter, firing angle, TRIAC.

Wavelet Transform and Fractal Theory for Detection and Classification of Self-extinguishing and Fugitive Power Quality Disturbances

In this paper, fractal theory and wavelet transform are combined to detect and classify self-extinguishing and fugitive scenarios of power quality disturbances (PQDs). After deciding whether the disturbance is simple or complex, the additional voltage is denoised through Discrete Wavelet Transform (DWT); the denoising process is adapted according to whether the distorted voltage contains oscillatory transients or not. At the detection stage, the grille fractal dimension of the DWT decomposition detail is computed. Then, a threshold is deduced to detect the start and end moments of the disturbance. The results reveal that the proposed detection scheme yields accurate location of PQDs even in the presence of high oscillatory transients. An algorithm based on geometric and statistical approaches is developed at the classification stage to recognize PQDs automatically. The geometric classification is based on Continuous Wavelet Transform (CWT), whereas the statistical classification is based on Multifractal Detrended Fluctuations Analysis (MFDFA) and an energy metric. The results prove that the combination of geometric and statistical classification can serve as an effective discrimination tool for PQDs. The major strength of the proposed approach is its ability to interpret the impact of each disturbance on the multifractal behavior of the nominal voltage, thus giving the possibility to draw the necessary generalizations for real-time applications.