Power Quality Evaluation of 480-V, 2-MVA UPS Systems

This study is aimed at designing, fabrication and evaluation of an efficient UPS based on locally obtainable material and conditions, for local application in academic environments. From a load survey, a load of 1.2 kW was obtained for Nigeria academics offices, which lead to the design of a 1.5 kVA UPS. A standard oscillating circuit based on CD4047 was adopted and adapted in the design. By loading requirements, 8 units of IRF250 MOSFETs were evaluated for the design. To improve the reliability (increase time to failure of battery) and effectiveness of the design, a battery charging controller and level detector were evaluated for addition to the design. The oscillatory circuit was tested using oscilloscope, and the open circuit and short circuit tests of the designed transformer for the construction was carried to define its efficiency. From the design, a square waveform of output voltage was obtained. The designed transformer efficiency obtained for the designed UPS is approximately 82%. A comparative technical and costs assessment show that the constructed UPS is cheaper but of less efficiency when compared with the imported 1.5 kVA products available in the Nigerian market

International journal of engineering research and technology, 2013

This paper evaluates the performance of common and popular brands of uninterruptible power supply in commercial sectors as power quality (PQ) mitigating equipment. The study was carried out in two phase. In the first phase, a sample of commercial users of UPS was collected from the population of users through a survey method and data collected were analyzed. The primary data were garnered using a well-structured questionnaire about UPS and field measurements. Descriptive statistics such as frequencies and bar chart were used in the analysis of data obtained from the survey. Also, series of tests were carried out on two brands of UPS (i.e. Mercury and Zinox brand of UPS) in order to ascertain their operating parameters against the standard. The survey shows relatively high rating of UPS as PQ mitigating equipment by the end-users. Also, the performance test carried out shows that they met the required standard and that locally branded type competes favourably with the foreign type. Appropriate recommendations were therefore made to ensure that both locally and imported manufactured UPS conforms to the required standard.

Procedia Technology, 2012

This paper provides the research and development of a solar powered UPS in Pakistan's market to meet the alternate energy source requirements of homes and small offices. It includes the design, analysis, research methodology used and the findings of the market study during the research. The design of the solar UPS includes a specially designed inverter circuit and a solar panel. The inverter circuit has been designed according to the requirements and specifications of solar panel. Many sample circuits have been studied to optimize the existing circuit. Assistance has also been taken from design engineers of existing UPSs in the market to see possible alternatives in case of any components' failure or unavailability. The paper provides study of possibilities of design and functionality of a solar powered UPS. It suggests that solar UPS can be a highly efficient and successful alternative to electrical UPSs in the market. There are two main components in the design: An outdoor solar panel comprising of solar cells, which will convert solar energy into electrical energy and inverter circuit that will convert that energy into alternating current to be used for home appliances.

International Journal for Research in Applied Science & Engineering Technology (IJRASET), 2022

This paper includes the research and development of a solar powered UPS in India's electrical market to satisfy the alternate energy source requirements of homes and tiny offices. During this paper circuit configuration, inspection, research pattern used and also the findings of the market study. The planning of the solar UPS includes a specially designed inverter circuit and a solar battery. The inverter circuit has been designed in keeping with the wants of domestic needs. The paper shows study of possibilities of design and functionality of a solar powered UPS. It gives concept that solar UPS is a highly efficient and successful alternative to electrical UPSs within the electrical market. There are two parts during this research first one is solar array which converts solar power into voltage and second is solar inverter which converts DC into electricity.

Energy Procedia, 2019

District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand-outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and validated by the authors. The results showed that when only weather change is considered, the margin of error could be acceptable for some applications (the error in annual demand was lower than 20% for all weather scenarios considered). However, after introducing renovation scenarios, the error value increased up to 59.5% (depending on the weather and renovation scenarios combination considered). The value of slope coefficient increased on average within the range of 3.8% up to 8% per decade, that corresponds to the decrease in the number of heating hours of 22-139h during the heating season (depending on the combination of weather and renovation scenarios considered). On the other hand, function intercept increased for 7.8-12.7% per decade (depending on the coupled scenarios). The values suggested could be used to modify the function parameters for the scenarios considered, and improve the accuracy of heat demand estimations.

IEEE Open Journal of Industry Applications, 2021

A challenge for industries nowadays is to enhance the functionality of their critical processes. Based on their design specifications and accuracies expected, these processes often tend to have a low tolerance to power disturbances. They require a high integrity power supply to guarantee their correct functioning, increase their robustness against the damaging effect of these disturbances. Network instability, lower energy availability, and poor power quality cannot guarantee this integrity of supply. The old coal-fired power stations have reached the end of their lives, and their reliability has decayed. The country now faces a major electricity crisis, which is why many industries are looking for systems that reduce their reliance on the national grid. The concept of critical power is going through a period of rapid changes. Uninterruptible power supplies (UPS) are required to increase their availability and manageability of power. Facilities are, therefore, called to revisit their concept of critical power and develop new supply methodologies. There is now a strong need to bring up innovative ways that dispatch the battery stored energy differently. Facilities must continually evaluate their time of energy use in relation to their tariff structures for better energy management and costs control. Time-of-use tariffs are structured to reward consumer who lowers their consumption during peak periods. The paper will present a comprehensive assessment that offers a site-specific solution to strengthen energy efficiency and reduce carbon footprint [24]. It will evaluate the financial impact that tariff structures and various modelled energy dispatch have on the facility energy budget. INDEX TERMS Utility tariff, return on investment, lithium-ion battery, battery storage system, total cost of ownership, storage capacity models, consumer price index.

International journal of advanced research in computer science and software engineering, 2017

Uninterruptible Power Supply (UPS) is increasingly becoming popular as a means of providing conditioned and uninterrupted power supply to sensitive and non-sensitive loads at critical and non-critical times.Sensitive modern equipment with very low tolerance for power fluctuation and failures are on the increase due to advancement in science and technology, theseequipment however require power backed up if they are to perform optimally. This study focuses on modification of the UPS in order to extend its running time.A used and dumped UPS working at a backup time of between 0 to 10mins was modified to accommodate two, 75AH Lead acid batteries, using 1400VA Zinox UPS. An extended backup time of between 2hrs to 8hrs on the same UPS using Lead Acid/Deep Cycle batteries was achieved which at the same time operating within a very low budget.

2013 15th European Conference on Power Electronics and Applications (EPE), 2013

Efficiency is a fundamental UPS performance criterion. Remarkably, UPS efficiency in field applications may deviate from controlled laboratory conditions. This paper focuses on the impact of mains supply on double-conversion UPS efficiency. As the mains supply mostly affects the rectifier section, the results also provide a reference on the impact of mains supply on rectifier efficiency.

International Journal of Electrical and Computer Engineering (IJECE), 2020

Energy-saving, improving energy efficiency, and finding a new efficient way to use energy are considered as an urgent problem in over the world. In this paper, we consider the economics of energy use in combination with energy storage units where two forms of electricity exist in the power system. Then the problem of optimizing the installation capacity (to optimize the investment costs for energy storage) is presented and investigated in connection with the conversion systems. The topic opens a very significant result, including the introduction of a mathematical model to calculate the simulation in optimizing the installation capacity of the equipment in the system, multi-source power, as well as voltage and power stability benefits. 1. INTRODUCTION This paper considers the problem, which related to the research project to improve economic and technical efficiency in the current period of the Russian Federation power systems. In fact, there have a two-price mechanism exists (electricity prices vary between peak and off-peak times) it is possible to receive some degree of energy cost savings when installing units. energy storage [1-12]. In this paper, we proposed the followings problems as 1) The level of cost savings of how energy is achieved and how to control the operation of the UPS to save costs; 2) The correlation of the capacity components of the load, the capacity of the supply network, the capacity of the converter and the capacity of the energy storage to how to save maximum cost; 3) the ability to stabilize the voltage in the system. These problems are the aim of this paper. The investment and operation of an energy storage device are significant for the owner of the load if it reduces energy costs. The power supply system can also finance the investment and operation of storage devices if it helps reduce the unevenness of the network. In optimizing energy consumption costs, it means that we will consider the issue of energy efficiency from the owners' perspective [13, 14]. This paper develops and solves the problem of determining the minimum cost of energy consumption when the ratios of power consumption of load components, converter power, and storage capacity amount. Assume that energy consumers consume only active power. The load characteristics are

iaeme

Increasing application of electronics to all kinds of appliances makes possible real time communication and continuous operation. This improves facilities performance levels through effective data & energy management. But electronic devices are non linear loads and introduce disturbance in the facility they are fed by. Therefore facilities & sensible equipment are becoming more dependent on both quality & continuity of electric power supply. In this paper an attempt is made to compare power quality aspects of DG set with utility supply. Harmonics at the out of DG set & single phase UPS (load fed from DG) were measured using Fluke 434 Analyzer. Harmonic effects are more pronounced when operated on DG because of its high internal impedance.