Harmonic Power Components Research Articles

The power harmonic components distribution study in the power circuit of a dynamic voltage restorer

Purpose. Investigation of the distribution of harmonic power components in the power circuit of a dynamic voltage restorer. Methodology. On the basis of the differential equations of the power circuit of a dynamic restorer, a search for the relationship between the mode parameters and the parameters of the circuit elements is performed. On the basis of the obtained expressions, a model of a dynamic voltage regulator was created using the methods of mathematical modeling in the visual programming environment.. Findings. The equations that reflect the relationship between the mode parameters of a dynamic voltage restorer and the parameters of circuit elements are obtained. As a result of modeling the mode with different harmonic composition of current and voltage, the following features of the distribution of instantaneous power components are revealed. Originality. It has been established that the presence of different current and voltage harmonics acting in the transformer of a dynamic restorer causes additional power harmonics that are transformed in the windings. It is noted that the low-frequency power harmonics of the LC filter dominate on the capacitor, which is connected in parallel to the transformer winding, while the level of high-frequency components caused by PWM modulation for the capacitor and the filter choke differ slightly. The zero-frequency power component of the storage capacitor corresponds to a tripled zero-time power component at the output of the converter, which is due to its operation in three phases. This cannot be extended to the second and third harmonics of the powers of the converter and the capacitor; these components are absent in the latter, which is due to energy exchange processes between the phases of the converter. Practical value. Using the obtained expressions, the principle of determining the parameters of the elements of the power circuit of a dynamic voltage restorer, in particular, the storage elements, is formulated.

Voltage and current profile improvement of a PV-integrated grid system employing sinusoidal current control strategy based unified power quality conditioner

The basic aim of the electric power sector is to produce power as when required at the suitable sites, then transmitting and distributing to various load centres retaining the quality and fidelity of supply with economical tariff. This paper focuses on mitigation of power quality (PQ) issues in a PV-integrated grid system by implementing constant Sinusoidal current control strategy (SCCS) based simulation of UPQC (Unified Power Quality Conditioner) using MATLAB R2016a in association with various loads. SCCS is a time domain control strategy established on instantaneous pq - theory. The UPQC is implemented to alleviate the harmonic component and again to countervail the complex power owed to their explicit and audacious exercise. The suggested technique assures sinusoidal quantities from source. Due to reactive power compensation, the current and voltage compensated components are in phase. As harmonic power is drawn due to non-linear loads, UPQC manages in supplying these harmonic power components restricting the same to be drawn from the supply. It manages harmonic power of the load as well as zero sequence power resulting to imbalances in the system. The results have been given and described in details explaining efficacy of the control strategy. SCCS is a simple and effective control strategy with tremendous potential to be applied in the Distributed Generation environment.

Macromodel of Spatial Smoothing in Wind Farms

Departing from aerodynamics (micromodel), the macromodel begins with the power output of a single wind turbine generator (WTG). The N units of WTGs in a wind farm are characterized by the time delays it takes wind, at average velocity, to traverse the distances separating them. Predictions from simulations are in agreement with recorded wind farm data. Smoothing of high-frequency power components is by a factor close to N-1/2. Smoothing of low-frequency harmonic power components is small because the wind farm is limited in size. A theory, based on Fourier analysis, is presented to explain how the macromodel simultaneously copes with: 1) the high-frequency components of wind velocity (which have poor correlation) even for short distances and 2) the low-frequency components (which have some correlation)

Correlation of damage, dry band arcing energy, and temperature in inclined plane testing of silicone rubber for outdoor insulation

Silicone rubber samples, filled with 30% alumina trihydrate, subjected to the ASTM inclined plane test, show good correlation between the measured harmonic power components of dry band arcing and the surface temperature recorded with a thermovision camera. The simultaneous study of the low frequency fast Fourier transform and variations in temperature shows that when the temperature rises above 100/spl deg/C there is a well defined increase in the low frequency harmonic components of the measured power; however, this trend is not verified by the fundamental component. The eroded mass of the samples is measured independently by a laser approach and a model to rank the tested samples using the inclined plane test is developed. The model is validated by applying it to both the recorded harmonic power components and temperature, resulting in the correct ranking of damage on the samples tested in the inclined plane test.