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The rapidly growing amount of social interaction makes geographical names an important and indispensable medium for people in social and economic exchanges. Especially in today's information age, the frequency of usage of name information has increased greatly. In this paper, a method for the construction of a cities' names database is proposed. This will include the processing of the outcome data...
Micro-grid architecture design is the basis of the micro-grid construction. It is necessary to follow certain design principles when designing micro-grid architecture, which differs from traditional distribution network designing. This paper describes several micro-grid architecture design principles, taking into consideration in the partition and hierarchy principle, as well as resource utilization...
HVDC converter produces a large number of harmonics, and these harmonics impact the surrounding environment. So it is need to reduce them effectively. This paper describes the mechanism of harmonics, and analysis of the characteristic of the harmonics. According to the characteristic, it puts forward corresponding suppression measures. Ac filter can absorb harmonic and reduce the harmonic at the connection...
The paper analyzes current researches on energy saving and evaluation of energy efficiency as well as the status of their applications. Based on the in-depth analysis and detailed study on energy consumption and energy efficiency, this paper put forward the concept of target energy and the concepts of working energy consumption, early energy consumption and extended energy consumption, expounding...
The global upsurge in research of smart grid and demand response (DR) is opening up new opportunities and challenges to China's power industry in recent years. The smart grid emphasize the interaction with user particularly, including the information interaction and power interaction, which are achieved through the deployment of various types of DR programs. Meanwhile, the development of smart grid...
In this paper, we mainly study the impacts of a small photovoltaic power station on voltage sag. Firstly, simulation model of photovoltaic power station is made in PSCAD. Secondly, we make the fault probability model of voltage sag based on Monte-Carlo method, and analyze two kinds of cases on grid-connected PV system: the same capacity in different location and the same location with different capacity...
Three-level inverters are increasingly being used in high power middle voltage applications due to their superior performance compared to two-level inverters. However, The neutral point fluctuation problem associated with the traditional three-level inverter like neutral-point clamped inverter is difficult to deal with. This paper proposes a novel three-level topology which is constructed by two three-phase...
Four kinds of compound carrier disposition PWM schemes are discussed, two of which are proposed for the first time in the paper. Methods for analyzing the amplitudes and harmonics of the output voltage of single-phase multi-level cascaded inverter are introduced for these PWM schemes, whose carrier waves could be equivalent to the ones of phase-shifted-PWM. Features of these PWM schemes are summarized...
Distributed generation technologies have emerged against bad environment and energy crisis, and they have been developed well in recent years. Lots of people have paid more and more attention to smart grid at home and abroad. This article analyzes the important role of the distributed power generation in the modern network's security and reliability, particularly the application and development of...
At present, the development of rural power grid can't meet the requirements of rapid economic development. The traditional single power grid is difficult to meet the request, and distributed power generations have a lot of advantages compared to it, particularly it's close to the end users, and they have been developed well and applied widely in recent years. This paper presents a distributed energy...
As one of the major problems of modern power quality, voltage sag will bring huge economic losses. From the economic point of view, assessment of voltage sags is discussed in the paper, on the basis of analyzing the main factors of voltage sag causing economic losses. According to the composition ratio and changes in voltage tolerance range of sensitive equipments, voltage tolerance curve (VTC) of...
In this paper, familiar means of energy storage are compared with respect to both performance and cost, on the basis of which some general rules are discussed on how to select proper energy storage means. Based on integrative analysis of capacity-fluctuation's impact on system and customers, some technical requirements of energy storage capacity configuration are determined. Proper capacity proportion...
A novel hybrid supplying system with DG based on the concept of energy pool is proposed in the paper. The hybrid supplying system consists of two layers: the dc layer collects unconstant power provided by distributed energy sources and forms an energy pool with some energy storage units; and the ac layer connects to the common power grid and exchanges energy as needed between the local supplying system...
A hybrid approach of load modeling based on statistics and typical models applying system response records under abnormal conditions is proposed in the paper. The major idea is to define load classes according to load composition, reproduce the composite loads in EMTDC to observe their characteristics, find static parameters from least squares methods, get motor parameters by weight average, and then...
Equivalent of multi-winding isolating transformers used in cascading power electronic devices havenpsilat gotten enough attention. In the paper, several sufficient conditions for radial equivalent of those transformers are discussed in detail, which are helpful for manufacturers to design and make such a transformer having radial equivalent circuit. Error analysis shows the effects of nonideal mutual...
It is difficult to find a reasonable and accepted index to evaluate the comprehensive level of power quality because of the great difference in characteristics and effects among all the individual problems. A new evaluation method is proposed which responses to what the customers care, based on the economical considerations. Example is given to show the advantages of the proposed method, including...
After analyzing typical structure of microgrids with distributed energy sources, a new idea of microgrid based on "DC energy pool" is proposed in the paper, whose energy exchanging process is also discussed. The new idea lays stress on the skillfully control of energy stored in the energy-storage device. Since the power balance within the microgrid is realized in a way with the help of distributed...
Under the guidance of Weiner's attribution theory, the author investigated and analyzed the college-students' attribution of computer rank examination in Zhejiang Province through interview and questionnaire survey. Results showed that there were defects in the student's attitudes as they regarded the external factors were more important and ignored the internal factors. In the examination, such factors...
Remarkable increase of agricultural load due to concentrative irrigation arrangement will consume a large amount of energy and impact the operation of power system. Traditional waterwheels require wind and water being together and can only deal with surface water, as will be unpractical in many areas. An irrigation system applying wind power generation is proposed. Wind energy is converted to electric...
Overall understanding on the nature and characteristics of the harmonics penetration between different voltage levels is necessary and significative. Factors affecting harmonic penetration are checked in the paper. After comprehensive analysis considering more than one factor simultaneously with the help of 3-dimension mesh plots, the distribution characteristics of with respect to key factors in...
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