Identification of Optimum Location of STATCOM in Transmission Line Employing RCGA Optimization Technique

Abstract: This study inspects the optimum location of STATCOM device in long transmission line to acquire the maximum power system transient stability improvement. STATCOM is a kind of prominent and effective shunt FACTS device which is used in power system to enhance the power system stability and to regulate the line voltage. When it has been placed at the center point of a transmission line, play a key role in controlling the reactive power flow and enhancing the power system transient stability. The active power losses caused by transmission line resistance alter the neutral position or optimum location of STATCOM in transmission line. RCGA optimization due to have high ability to solve non-linear objective function has been implanted to identify the optimum location of STATCOM. The results of non-linear simulation under severe disturbance approve that the optimum location of STATCOM in order to access the maximum power system transient stability by reducing the active power losses approaches to midpoint of transmission line

Extending vase life of cut rose (Rosa hybrida L.) cv. Bacara by essential oils

Recent studies showed that some essential oils functions as antibacterial compounds. In this study results showed treatment with essential oils promoted vase life of cut roses via decreasing bacteria number inside the stem. We investigated components in the hydrodistilled essential oils of Bunium persicum Bioss, Mentha spicata L., Thymus vulgaris L. and Satureja hortensis L., as hold solutions, and their effects on relative fresh weight, water uptake, vase life, electrolyte leakage, anthocyanin content, soluble sugar content and number of bacteria at stem end of cut flowers of rose. GC-MS analysis of the extracted essential oil of B. persicum, M. spicata, Th. vulgaris and S. hortensis L. led to the identification of 14, 20, 13 and 14 major compounds, respectively. In cut rose, the treatment containing the essential oils extended flower opening period longer than the control. The 200 µl l-1 essential oil of M. spicata treatment almost doubled the vase life of cut roses. Hence these essential oils might be powerful, environmentally friendly substitutes for the chemical compounds currently added to vase waters to control bacterial content

The Dynamic Sliding Mode Controller with Observer of Coincident Perturbations and States for Buck Converter of Fuel Cell Source

Buck converter has been widely used in the DC renewable energy system application. The Fuel Cell (FC) based DC renewable energy is offered as a high-performance and low-emission power supply, which replaces conventional DC sources. Its relevant control system has regulated the output voltage under input voltage and load resistance variations to track the desired reference signal. To control the current sensorless-based buck converter with matched and mismatched uncertainties, the sys-tem must be modeled in such a way that by measuring the output voltage, both the inductor current and system perturbations can be estimated. The purpose of the work is suggestion of a novel dynamic sliding mode controller (DSMC) based on observer of coincident perturbations and states (CSPO) to enhance its controllability and tracking performance. The significance of the work lies in low cost and reduced losses due to the inductor current measurement. Lacking an exact value for inductor current, it is not possible to estimate and compensate the perturbations caused by parametric uncertainties in the buck converter. These objectives were achieved by modeling in the canonical form. The canonical model somehow converts both the matched and mismatched perturbations into the matched perturbation, in which the system states and perturbations can be merely estimated using only an output volt-age value and a CSPO. The most important results are the fastness and robustness of the DSMC to control the buck converter and compensate the effect of mismatched uncertainties and nonlinear dis-turbances and chattering phenomenon

Enhancement of DFIG-Wind Turbine’s LVRT capability using novel DVR based Odd-nary Cascaded Asymmetric Multi-Level Inverter

One of the most prominent issues relevant to Doubly Fed Induction Generator (DFIG) is augmentation of its Low Voltage Ride Through (LVRT) capability. Dynamic Voltage Restorer (DVR) is a series kind of Distributed-Flexible AC Transmission Systems (D-FACTS) that is here occupied to preserve the DFIG from the voltage sag whenever a fault to be occurred in the power system. Multi-Level Inverter (MLI) is the beating-heart of DVR with unique responsibility of synthesizing a staircase sinusoidal voltage from the DC voltage sources. In this regard, it is immensely important a high performance and cost-effective MLI to be embedded into the DVR. In this paper, a novel MLI is introduced to provide a staircase sinusoidal voltage with high level numbers against less switch numbers as compared to the other kinds of MLIs. By adding the bi-directional switches and capacitors of sub-MLI as well as amount of DC sources, the held forth MLI can also operate as so-called “Odd-nary” Cascaded Asymmetric Multi-Level Inverter (OCAMLI). The performance of proposed DVR based on OCAMLI i.e., DVR-OCAMLI has been thoroughly evaluated under deep and shallow balanced and unbalanced voltage sags so that its LVRT capability to be cleared up. To more scrutinize the performance of DVR-OCAMLI, it has been withal dealt with under severe and slight voltage swells as well as harmonic voltage. The accuracy and performance of DVR-OCAMLI has been furthermore compared with conventional DVR. To sum up, the relevant analytical study along with the simulation results has transparently corroborated the performance of OCAMLI as compared to other MLIs. Meanwhile, the DVR-OCAMLI has significantly compensated deep and shallow symmetric and asymmetric voltage sags to enhance the LVRT capability of DFIG; correspondingly, the severe and slight symmetric and asymmetric voltage swells as well as voltage harmonic have been exceptionally compensated as compared to conventional DVR

Optimal placement of distribution network‐connected microgrids on multi‐objective energy management with uncertainty using the modified Harris Hawk optimization algorithm

Abstract Considering the importance of the renewable energy sector in the distribution systems, energy operation, and management which are connected to the distribution network (DN) in the form of multiple microgrids (MMGs) is crucial in reducing cost and pollution. Hence, this paper aims to propose optimal energy management for MMGs in the DN. Different objective functions have been taken into account in this optimization, including network cost, pollution reduction, and distribution network power losses. To design the multi‐objective optimization problem, a fuzzy method has been adopted for simultaneous multi‐objective calculations. Furthermore, the effect of the placement of distributed generations (DGs) and microgrids (MGs) is considered to reduce the distribution network power losses. Information gap decision theory (IGDT) has formulated uncertainties about renewable sources and consumers. To solve this optimization problem, a new method of the modified Harris Hawk optimization (MHHO) algorithm has been implemented, compared with the original HHO and genetic algorithm (GA). Finally, the proposed method has been analysed under the IEEE 33‐bus distribution network for a 24‐hour time horizon, including three MGs considering different renewable energy sources (RESs). The simulation results have demonstrated the high performance of the allocated network with the MHHO algorithm compared to the other scenarios