scholarly journals Talking about the significance of optimizing the condition evaluation standard of small power grid equipment such as voltage transformer

2020 ◽  
Vol 185 ◽  
pp. 01049
Author(s):  
Suya Li ◽  
Cong Zhao ◽  
Yanwei Dong ◽  
Songyuan Li ◽  
Nan Li ◽  
...  
Keyword(s):  
Power Systems ◽  
High Efficiency ◽  
Low Cost ◽  
Power Grid ◽  
Stable Operation ◽  
Voltage Transformer ◽  
Evaluation Standards ◽  
Evaluation Standard ◽  
State Evaluation ◽  
Condition Evaluation

Power grid equipment condition evaluation and condition maintenance is a kind of operation and maintenance means with strong reliability, low cost and high efficiency in power grid equipment operation management. At present, when carrying out state assessment of power grid equipment such as, grounding devices, capacitors, reactors, because of the features of large number, frequent failures, complex and changeable operating environment, etc, existing state evaluation standards have obvious deficiencies, which makes it difficult to meet management needs. Optimizing state evaluation standards, formulating scientific and effective state evaluation guidelines are of great significance for improving equipment safety and ensuring safe and stable operation of power systems.

scholarly journals Performance Index: A Simple Selection Method of Appropriate Energy Storage for Specific Application

2018 ◽  
Vol 171 ◽  
pp. 01002
Author(s):  
Hussein Ibrahim ◽  
Mazen Ghandour ◽  
Sabine Saad
Keyword(s):  
Energy Storage ◽  
Power Systems ◽  
Performance Index ◽  
High Efficiency ◽  
Low Cost ◽  
Storage Devices ◽  
Renewable Power ◽  
Storage Methods ◽  
Simple Selection ◽  
Term Storage

The efficiency and cost of renewable power systems using intermittent resources could significantly be improved by developing low cost, high efficiency and more sustainable energy storage systems. There are various types of storage methods, some of which are already in use, while others are still in development. A comparison study between energy storage options is presented in this paper. We have taken a look at the main characteristics of the different electricity storage techniques and their field of application (permanent or portable, long-or short-term storage, maximum power required, etc.). These characteristics will serve to make comparisons in order to determine the most appropriate technique for each type of application. Based the results obtained in this study, a “performance index” have been determined for each storage technology in order to facilitate the comparison between the different storage devices.

scholarly journals H7 three phase transformerless inverter for photovoltaic grid-tied system with maximum power point operation

2021 ◽  
Vol 12 (3) ◽  
pp. 1853
Author(s):  
Essam Hendawi ◽  
Sherif Zaid
Keyword(s):  
Power Systems ◽  
Leakage Current ◽  
High Efficiency ◽  
Low Cost ◽  
Harmonic Distortion ◽  
Boost Converter ◽  
Phase Inverter ◽  
The Earth ◽  
Three Phase ◽  
Three Phase Inverter

<span lang="EN-US">One of the most important and common parts of the modern power systems is the grid-connected photovoltaic (PV) systems. Recently, these systems have gotten a big revolution due to the introduction of the transformerless inverters. It has the merits of small size, low cost, and high efficiency. However, transformerless inverters has a general safety problem related to the earth leakage current. Various researches were directed toward evolving their performance and diminishing the leakage current to the standard limits. This article proposes an application of the H7 controller to a PV powered grid-tied three phase transformerless inverter. The transformerless inverter is linked with the grid through a boost converter. The boost converter inductance is rearranged and divided to reduce the earth leakage current of the system. simulations are carried out for the proposed H7 PV grid-tied system and for a system that uses the conventional three phase inverter. The simulation results show that the H7 inverter provides lower leakage current, higher efficiency, and lower total harmonic distortion (THD) compared to the conventional three phase inverter.</span>

Recent Patents on Wall Climbing Robot with Negative Pressure Adsorption

2019 ◽  
Vol 13 (3) ◽  
pp. 201-211
Author(s):  
Dedong Tang
Keyword(s):  
Negative Pressure ◽  
Manufacturing Industry ◽  
High Efficiency ◽  
Low Cost ◽  
Nuclear Industry ◽  
Stable Operation ◽  
Human Beings ◽  
Climbing Robot ◽  
Fire Control ◽  
Human Labor

Background: The wall climbing robot is an automatic mechanical device capable of being adsorbed on the wall surface and carrying out various predetermined work. Compared with human labor, the wall climbing robot has the advantages of high efficiency, low cost and stable operation quality. It can replace human beings to accomplish various dangerous work, reduce the risk and labor intensity of high-altitude operation, and greatly promote the improvement of productivity. At present, wall climbing robot has been widely used in the construction industry, fire control, nuclear industry, petrochemical industry and manufacturing industry. Objective: I will review related patents of wall climbing robot with negative pressure adsorption and illustrate their structure and working principle. The results of the analysis can provide some meaningful reference for the optimal design of this kind of robot. Methods: Based on the comparative analysis for the latest patents related to wall climbing robot with negative pressure adsorption, the key problem and future development of the wall climbing robot are put forward. Results: The patents of the wall climbing robot with negative pressure adsorption are classified in the paper. Studies show that remarkable improvements have been achieved in the invention on the climbing robot. Conclusion: In the tomorrow, the adsorption technology, optimization of moving mode, structure miniaturization and intelligent control should be further studied.

Low cost regulation and load control system for low power wind turbine

2017 ◽  
Vol 10 (28) ◽  
pp. 1391-1399
Author(s):  
Yonatan Ochoa ◽  
Jhon Rodriguez ◽  
Fredy Martinez
Keyword(s):  
Wind Turbine ◽  
Electric Power ◽  
Low Income ◽  
High Performance ◽  
High Efficiency ◽  
Low Cost ◽  
Power Grid ◽  
Load Control ◽  
Regulation System ◽  
Control Circuits

Context: Electric power generation systems designed as a point solution to supply needs away from the power grid typically make use of the energy resources available in the area. These systems are custom designed to supply a specific need, and with high efficiency criteria in mind. A fundamental element in these systems are the batteries charge and control circuits. Method: The regulation system was designed for the wind turbine prototype of the Francisco Jos de Caldas District University, campus of the Technological Faculty, and considering its use in low-income housing. The module has three intermediate stages of regulation: rectification and conditioning, DC/DC regulation and battery charging, and voltage inversion. Results: We achieved a prototype of high efficiency, low cost and high performance in laboratory tests. Conclusions: The load control and regulation system is a low-cost, high-performance alternative to solve problems of supplying electric power in non-interconnected areas of the Colombian power grid.

Research on a Transonic Supercritical Carbon Dioxide Centrifugal Turbine

2019 ◽  
Vol 5 (4) ◽  
Author(s):  
Zehai Yang ◽  
Dan Luo ◽  
Diangui Huang
Keyword(s):  
Carbon Dioxide ◽  
Numerical Simulation ◽  
Performance Analysis ◽  
Supercritical Carbon Dioxide ◽  
Energy Conversion ◽  
High Efficiency ◽  
Low Cost ◽  
Thermodynamic Cycle ◽  
Stable Operation ◽  
Supercritical Carbon

Recently, the supercritical carbon dioxide Brayton (SCO2) cycle gained a lot of attention for its application to next-generation nuclear reactors. Turbine is the key component of the energy conversion in the thermodynamic cycle. Transonic centrifugal turbine has advantages of compatibility of aerodynamic and geometric, low cost, high power density, and high efficiency; therefore, it has opportunity to become the main energy conversion equipment in the future. In this paper, a transonic nozzle and its corresponding rotor cascade of the single-stage centrifugal turbine were designed. In addition, the three-dimensional (3D) numerical simulation and performance analysis were conducted. The numerical simulation results show that the predicted flow field is as expected and the aerodynamic parameters are in good agreement with one-dimensional (1D) design. Meanwhile, the off-design performance analysis shows that the transonic centrifugal turbine stage has wide stable operation range and strong load adaptability. Therefore, it can be concluded that the proposed turbine blade has good performance characteristics.

Identification of topology changes in power grids via reduced admittance matrix

2021 ◽  
Author(s):  
Ling Lin ◽  
Li Ding ◽  
Zhengmin Kong ◽  
Chaoyang Chen
Keyword(s):  
Power Systems ◽  
Power Grid ◽  
Measurement Data ◽  
Least Square Method ◽  
Least Square ◽  
Measurement Unit ◽  
Stable Operation ◽  
Admittance Matrix ◽  
Topology Changes ◽  
Grid Topology

Frequent changes in power grid topology bring risks to the stable operation of power systems. It is essential to identify changes in the power grid topology quickly and accurately. This paper presents a novel method named network reduction-based topology change identification (NR-TCI) algorithm to identify topology changes in multi-machine power systems. The proposed algorithm can quickly identify power grid topology changes using only phasor measurement unit (PMU) data sampled during the system’s transient process. The NR-TCI algorithm uses the network order reduction method to reduce the order of a bus admittance matrix and then uses PMU measurement data to estimate the reduced admittance matrix by least square method. Finally, the reduced admittance matrix is adopted to find topological information, and the Sherman–Morrison formula is utilized to identify the topology changes. The effectiveness of the proposed NR-TCI algorithm is verified with a case study of a 3 machine 9 bus system in Matlab. In addition, the influence of PMU sampling frequency on the effectiveness of the proposed algorithm is also studied.

Shaped Magnetic Field in Resonance Technology and its Application to Transportation System

2015 ◽  
Author(s):  
Dong-Ho Cho ◽  
Nam Pyo Suh ◽  
Uooyeol Yoon ◽  
Guho Jung
Keyword(s):  
Magnetic Field ◽  
Electric Vehicles ◽  
High Speed ◽  
High Efficiency ◽  
Low Cost ◽  
Power Grid ◽  
High Capacity ◽  
Power Transfer ◽  
Charging Infrastructure ◽  
The Road

KAIST has developed the Shaped Magnetic Field in Resonance (SMFIR) technology that transfers a large amount of energy to electric vehicles when they are running or stationary. The wireless charging SMFIR technology provides a solution to the commercialization barriers of electric vehicles such as the problems of batteries and charging infrastructure. Using 20-kHz wireless power transfer system based on the SMFIR technology, our eco-friendly On Line Electric Vehicle (OLEV) bus was wirelessly powered by 100 kW through a power grid embedded under the road. On the other hand, using high-capacity, high-efficiency and low-cost 60kHz power supply and pickup systems based on the SMFIR technology, tram and high speed train were wirelessly powered by 180 kW and 1 MW through a power grid built in rail roads, respectively. The commercial OLEV tram has been operated commercially from July 2011 in Seoul National Grand Park. Also, the OLEV shuttle bus has been operated for convenience of students and faculty members at KAIST campus since Oct. 2012. In addition, the world’s first intra-city OLEV bus with 100 KW pickup capacity has been operated commercially at Gumi city from March 2014. Then, airgap is about 20 cm and maximum power transfer efficiency is 85 %.

scholarly journals Application of Hybrid HS and Tabu Search Algorithm for Optimal Location of FACTS Devices to Reduce Power Losses in Power Systems

2016 ◽  
Vol 6 (6) ◽  
pp. 1217-1220 ◽  
Author(s):  
Z. Masomi Zohrabad
Keyword(s):  
Tabu Search ◽  
Power Systems ◽  
Energy Demand ◽  
Power Flow ◽  
Search Algorithm ◽  
Low Cost ◽  
Power Grid ◽  
Harmony Search ◽  
Unified Power Flow Controller ◽  
Tabu Search Algorithm

Power networks continue to grow following the annual growth of energy demand. As constructing new energy generation facilities bears a high cost, minimizing power grid losses becomes essential to permit low cost energy transmission in larger distances and additional areas. This study aims to model an optimization problem for an IEEE 30-bus power grid using a Tabu search algorithm based on an improved hybrid Harmony Search (HS) method to reduce overall grid losses. The proposed algorithm is applied to find the best location for the installation of a Unified Power Flow Controller (UPFC). The results obtained from installation of the UPFC in the grid are presented by displaying outputs.

Lifetime Optimization for a Grid-Friendly DC Fast Charge Station With Second Life Batteries

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Matilde D’Arpino ◽  
Massimo Cancian
Keyword(s):  
Power Systems ◽  
Second Life ◽  
Low Cost ◽  
Power Grid ◽  
Management Control ◽  
Fast Charge ◽  
Grid Connection ◽  
Concurrent Optimization ◽  
Lifetime Optimization ◽  
Definition Of

Abstract Electrified vehicle (EV) batteries that have reached the automotive end of life are providing a low-cost energy storage solution for grid-connected systems, such as DC fast charge stations (DCFCs). There are several challenges associated with the integration of second life batteries (SLBs) in power systems, such as the definition of a systematic approach for the concurrent optimization of performance and lifetime with the aim of minimizing the investment and operating costs. This paper proposes the application of automotive SLBs to DCFC stations where high-power grid connection is not available or feasible. The SLBs are charged using a low-power grid connection and then provide DCFC power to the EVs. An optimal control problem has been formulated to identify the energy management control (EMC) strategy that allows minimizing the replacement rate of the SLBs, while ensuring the EV load request is match.

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