无功补偿外文翻译

西南交通大学本科毕业设计英文文献翻译年级: 2010级学号: **********: ***专业: 电气工程及其自动化****: ***2014年6月西南交通大学本科毕业设计（论文）第页2第2页Industrial enterprises of reactive power compensationFrom:Power System Analysis and DesignAbstractThe improvement of industrial enterprises is to improve the power factor of electric power efficiency，an important means of saving energy. In this paper，theoretical analysis and application examples of the industrial enterprises，the significance of reactive power compensation and the role and view of the current power system，industrial enterprises，the problems for the proposed improvements and measures.IntroductionIn industrial enterprises，the vast majority of electrical equipment belongs to perceptual load，these devices in operation to absorb a large number of reactive power. An increase in reactive power supply system power factor to lower system voltage drop to occur，electrical equipment not fully utilized，increasing line losses and lower-powered equipment，power supply capacity and so on. In situ reactive power compensation and thus improve the power factor of the Energy Conservation has extremely important significance.The choice of method of compensationCompensation for reactive power compensation is divided into centralized and decentralized compensation for three kinds of compensation and in situ. Focus on compensation，that is，high and low voltage power distribution set up by several groups within the capacitor，capacitor connected to the power distribution bus，the compensation for the distribution of power within the reactive power，and to reach the required value of the total power factor above. This method of compensation can compensate for high and low voltage bus routes prior to the reactive power，which is equivalent to the reactive power source to move the electricity distribution companies，allowing users to power the systemrequirements for reactive power has been reduction in the electricity sector to achieve the required power factor. And their distribution within the enterprise bus following the line of transformer and reactive power compensation can not play a role，there is still a large number of reactive power line flows within the enterprise and generate losses. Dispersion compensation is the capacitors were installed at various workshops at the switchboard，which will enable installation of distribution transformer and the substation to the plant lines can be due to a decrease in reactive load compensation effect. Local compensation is the reactive power compensation device directly connected to the induction motor terminals on the side or into the line. Focus on compensation methods used in the capacity of capacitor compensation or in-place than the grouping of compensation should be small，its utilization rate is even higher disadvantage is the change in distribution has not been compensated by the feeders，only lightened the load reactive power grid. Dispersion compensation in the way the utilization of capacitor compensation than the in situ high，so the total requirement of compensation is smaller than the spot is an economical and reasonable remedy. Reactive power compensation should follow the "overall planning，rational distribution，classification of compensation，in-place balance; focus on compensation and dispersion compensation combine to spread-based compensation; high compensation and low voltage compensation combined with low-pressure-based compensation; Regulator combined with lower losses，down are the main loss "principle [1]. Compensation capacity to determineIn the power grid in the reactive power consumption is a big，about 50% of the reactive power consumed in transmission，transformation and the device，50% of the consumed electricity users. In order to reduce reactive power consumption，it is necessary to reduce the reactive power in the grid where flow. The best way to start from the user to increase reactive power compensation，improve user load power factor，so that Generator reactive power can be reduced and the reduction of transmission，transformation and distribution equipment in the reactive power consumption，so as to achieve the purpose of reducing wear and tear [2]. Compensation for reactive power capacity of Qc for22121111cos cos c av Q P ϕϕ⎡⎤=---⎢⎥⎣⎦ Load changes can be decided according to the static or dynamic compensation mode. When the load change is relatively stable ， we should use the static method of compensation ， which can not only reduce the line losses ， and investment; when the load change is large ， dynamic compensation method should be used ， stable voltage [3]. Reduce line lossesIs located at a rated voltage ， active power is constant ， due to power factor changes ， the line loss rate of change ΔP% for the212cos %1()100%cos P ϕϕ⎡⎤=-⨯⎢⎥⎣⎦ As can be seen from Table 1 to improve the power factor in lowering power consumption ， improving economic efficiency plays an important role.Table 1 Power factor and power loss percentage of the corresponding dataIf a constant active power condition ， the original power factor cosφ1 of 0.59， compensated power factor cosφ2 of 0.98， its line loss rate reduction ΔΡ% to 64%. Dynamic compensation device ，Group to track the power capacitor compensation ， power factor can be different from the stability provided in the context of the power factor to achieve adequate compensation purposes.Lines ， transformer capacity increaseLines ， transformer capacity increased ΔS for the12cos 1cos S S ϕϕ⎛⎫=⨯- ⎪⎝⎭Additional compensation device ， may improve the power factor ， power factor on the business of direct economic benefit is obvious. Because the state electricity system ， starting from the rational use of energy ， according to the power company to adjust the price due to high and low values. The compensation device for enterprise and the entire power system economic operation all have significant economic effects .To improve the voltage qualityTo improve the voltage quality is the dynamic reactive power compensation equipment installed around the role of place in the line voltage compensation has increased slightly . 12211100%U U tg x U Q R tg xϕϕ-=⨯=+ Where tgφ1 - compensation device is not installed before the φ1 angle tangent; tgφ2 - compensation equipment installed after the φ2 angle tangent; R ， x --- line resistance ， reactance.Industrial enterprises for the power system problems and solutionFig 1 for a diagram of power supply systems for heavy machine tool plant. At present ， the total capacity of the plant transformer 17660kV A ， a total of 20 transformers (1 # ~ 20， # transformers)， each transformer capacity range of 50 ~ 1250 kV A ， changing the ratio of 10kV / 014kV . Transformer low voltage side of the load is mainly motor ， shown in the M1， M2 Mn shown. In general the rate of transformer load is basically maintained at 28% ~ 29%， and the maximum load of 7000kW.High and low voltage compensation to replace a combination of high concentration of compensationFrom the figure we can see the plant supply network focused on high-voltage power factor compensation is compensation that is only in the high-voltage busbar 10kV substation capacitor banks on the pick ， while the low pressure has not taken any compensation measures. The fixed capacitor compensation method there have been compensation or due compensation ， and right below the second power supply bus powerfactor compensation circuit does not work. As the low power factor caused by the line losses and transformer equipment is a big loss，so compensation as far as possible whengrading，installation of capacitors near the load. Therefore proposed that the high side to focus compensation and dispersion compensation for low-voltage side of a combination of method of compensationFigure 1Power Supply System of a Heavy Machine Tool Plant diagramTo change the power supply as much as possible to avoid the "big horse-drawn cart" phenomenonIn making our selection，we should consider leaving a certain margin，to prevent heavy damage to equipment when，so most of the time caused by equipment，and severe underrun underrun the formation of the "big horse-drawn cart" Run. As the plant load factor of the transformer is basically 28% ~ 29%，and shows the transformer capacity is too large，transformer capacity can not be fully utilized，not only a waste of investment in equipment has increased the power loss. Rational choice by the transformer capacity and electrical equipment to reduce or limit the light-load or no load time to prevent the "big horse-drawn cart" phenomenon.To avoid the no-load operation of equipmentAt present，the plant is running a serious load of some equipment. Improving thepower factor，the first consideration should be given a reasonable run the equipment to improve power factor of power the device itself. The plant main load is AC motor，its power factor load with it change，motor idling，the power factor of about 0.1 ~ 0.3 between the rated load at 0.8 ~ 0.85 between the motor and thus should be made near the. rated load state run. We should improve the motor power factor，the simplest way is to use capacitors and electric motors in parallel，so to avoid the no-load operation device is to improve the power factor equipment，an important way.Economic Benefit AnalysisTo the factory power supply system in two # transformers，for example，installation of capacitors in the low voltage side，so that high-pressure side of the plant to focus on compensation and dispersion compensation combination of low-voltage side of a compensation formula，shown in Figure 2. Graph 2 #transformer capacity of 800kV A，model S9 - 800 / 10，rated copper loss for the 715kW，transmission line model YJV22. Get price of 0.55 yuan / kWh. The power factor by the compensation prior to 0.59 to compensate for post-0.98，Table 2 is the use of measuring instruments measured in the field of transformer secondary side run-time data are analyzed by calculating the loss of reactive power compensation reduced energy efficiency.Figure 2 foundry supply diagramTable 2 transformer secondary-side run-time data tableThe energy-saving high-voltage power linesThroughout the year to save electricityΔW = 1P hWhere 1P l- the increase in electric power lines ，22112cos 31cos P I R ϕϕ⎡⎤⎛⎫⎢⎥=- ⎪⎢⎥⎝⎭⎣⎦ The number of annual operating hours ， whichever 5000h. The calculation of annual energy savings 162217kW.h ， within one year to reduce electricity consumption costs 81.92 million yuan.Transformer-savingThe loss of main transformer iron loss and copper loss. Transformer secondary side to improve the power factor ， can reduce the total load current ， thereby reducing the copper loss. Transformer copper loss of the year to save energy ΔW = (ΔPCu1 - ΔPCu2) h where ΔPCu1 - compensation for the actual run-time before the transformer copper loss of electric power ，211Cu CuN N I P P I ⎛⎫= ⎪⎝⎭ ΔPCu2 - compensated transformer copper loss of electric power ，21212cos cos Cu CuN P P ϕϕ⎛⎫= ⎪⎝⎭ The calculation of annual energy savings 3150kWh ， within a year to save electricity transformer copper loss of 173，518 yuan.Power Factor Adjustment tariffUsers within a year to reduce spending more than the low power factor penalty: 800 × 0. 589 × 5000 × 0.55 × 17.22% (increase rate) = 221.31 million yuan of compensation within one year after the users get the power factor bonus: 800 × 0. 589 × 5000 × 0.55 × 2.7% (reduced rate) 3.15 million total of 251.81 million yuan from the two above calculations we can see an overall increase within one year of net income 341.73 million yuan ， according to the capacity required to compensate for equipment investment 27.15 million yuan ， 9 months will be able to recover their investments. This shows that the plant foundry for the specific circumstances of the transformer secondary side compensation for use of decentralized approach to reactive power compensation is feasible and can achieve long-term and significant economic effects.10kv无功补偿摘自——《电力系统分析和设计》摘要提升工业企业用电效率、节约电能的重要手段和方法就是改善电能消耗的功率因数。