Electrical Energy Transmission（电能输送）毕业论文外文翻译.doc

Page1 Electrical Energy Transmission（电能输送） From reference 1 Growing populations and industrializing countries create huge needs for electrical energy. Unfortunately, electricity is not always used in the same place that it is produced, meaning long-distance transmission lines and distribution systems are necessary. But transmitting electricity over distance and via networks involves energy loss.So, with growing demand comes the need to minimize this loss to achieve two main goals: reduce resource consumption while delivering more power to users. Reducing consumption can be done in at least two ways: deliver electrical energy more efficiently and change consumer habits.Transmission and distribution of electrical energy require cables and power transformers, which create three types of energy loss:the Joule effect, where energy is lost as heat in the conductor (a copper wire, for example);magnetic losses, where energy dissipates into a magnetic field;the dielectric effect, where energy is absorbed in the insulating material.The Joule effect in transmission cables accounts for losses of about 2.5 % while the losses in transformers range between 1 % and 2 % (depending on the type and ratings of the transformer). So, saving just 1 % on the electrical energy produced by a power plant of 1 000 megawatts means transmitting 10 MW more to consumers, which is far from negligible: with the same energy we can supply 1 000 - 2 000 more homes.Changing consumer habits involves awareness-raising programmers, often undertaken by governments or activist groups. Simple things, such as turning off lights in unoccupied rooms, or switching off the television at night (not just putting it into standby mode), or setting tasks such as laundry for non-peak hours are but a few examples among the myriad of possibilities.On the energy production side, building more efficient transmission and distribution systems is another way to go about it. High efficiency transformers, superconducting transformers and high temperature superconductors are new technologies which promise much in terms of electrical energy efficiency and at the same time, new techniques are being studied. These include direct current and ultra high voltage transmission in both alternating current and direct current modes.出自文献 1：人口增长和工业化国家导致电力能源的庞大需求量. 不幸的是, 电力的使用和生产常常不是在相同的地方，意味着长距离传输线路配电系统是必需的. 然而长距离输电以及通过网络这就涉及到能量损耗的问题。.所以，随着需求的增长，就要使得这个损耗最小化，以达到两个主要目标: 在减少资源消耗，同时为用户传送更多电能。至少有两种方式可以实现减少消耗量：更有效地传送电能以及改变用户的习惯。电能的传输和分配需要电缆和电力变压器, 他们产生三种类型的能量损失：焦耳效应, 那些在导体发热过程中损失的能量(例如铜金属线)；电磁损耗, 这部分能量被转化为电磁场；电介质效应, 这部分能量在绝缘材料中被吸收。传输电缆中的焦耳效应导致大约2.5 % 的损耗，电力变压器中这个损耗大约在 1 %到 2 %之间 (取决与变压器的类型和电压等级). 所以在1000兆瓦的发电厂产出的电能中节省仅仅1%就意味着向用户传输了10 MW 能量，这是远不可忽视的：和它相同的能量，我们可以提供给1 000 - 2 000个家庭。 改变消费习惯涉及到宣传计划，这常常由政府或积极团体进行。这仅是些简单的小事，例如关掉无人房间的灯，或在晚上关掉电视（不只是把它进入待机模式），或把洗衣服安排在非高峰时段，这仅仅是无数的可行性中的几个例子。 在能源生产方面，建立更有效的传输和分配系统是减少损耗的另一种方式。高效变压器、超导变压器、高温超导体是能够保证电能效率的新技术，同时我们要研究新的工艺。这包括交直流切换模式下的直流和特高压输电。 From reference 2Disturbing loads like arc furnaces and thyristor rectifiers draw fluctuating and harmonic currents from the utility grid. These non sinusoidal currents cause a voltage drop across the finite internal grid impedance, and the voltage waveform in the vicinity becomes distorted. Hence, the normal operation of sensitive consumers is jeopardized.Active filters are a means to improve the power quality in distribution networks. In order to reduce the injection of non sinusoidal load currents shunt active filters are connnected in parallel to disturbing loads (Fig. 1). The active filter investigated in this project consists of a PWM controlled three-level VSI with a DC link capacitor.The VSI is connected to the point of common coupling via a transformer. The configuration is identical with an advanced static var compensator.The purpose of the active filter is to compensate transient and harmonic components of the load current so that only fundamental frequency components remain in the grid current. Additionally, the active filter may provide the reactive power consumed by the load. The control principle for the active filter is rather straightforward: The load current ismeasured, the fundamental active component is removed from the measurement, and the result is used as the reference for the VSI output current.In the low voltage grid, active filters may use inverters based on IGBTs with switching frequencies of 10 kHz or more. The harmonics produced by those inverters are easily suppressed with small passive filters. The VSI can be regarded nearly as an ideally controllable voltage source. Inmedium voltage applications with power ratings of several MVA, however, the switching frequency of todays VSIs is limited to some hundred Hertz. Modern high power IGCTs can operate at around 1 kHz. Therefore, large passive filters are needed in order to remove the current ripple generated by the VSI. Furthermore, in fast control schemes the VSI no longer represents an ideal voltage source because the PWM modulator produces a considerable dead-time. In this project a fast dead-beat algorithm for PWM operated VSIs is developed 1.This algorithm improves the load current tracking performance and the stability of the active filter. Normally, for a harmonics free current measurement the VSI currentwould be sampled synchronously with the tips of the triangular carriers. Here, the current acquisition is shifted in order to minimize the delays in the control loop. The harmonics now included in themeasurement can be calculated and subtracted from the VSI current. Thus, an instantaneous current estimation free of harmonics is obtained.出自文献 2：例如电弧炉和可控硅整流器这样的配电网负载会对公用电网产生扰动和谐波电流。这些非正弦电流导致有穷网络的内部阻抗电压下降，在附近的电压波形产生畸变。因此，对电压敏感的用户的正常运作受到损害。 有源滤波器是一种手段，以提高配电网电能质量。为了减少注入的非正弦负荷电流，通过并联有源滤波器来重新分配负荷(图1)。有源滤波器包括了PWM三级控制逆变器的直流环节的电容器。逆变器通过变压器进行公共连接，这样的配置等同于一种先进的静态变量补偿器有源滤波器的目的是为了补偿瞬态和谐波分量负载电流的基本频率成分,所以只留在栅极电流。此外,有源滤波器可以提供无功功率被负荷。控制原理,介绍了有源滤波器很简单:负载电流活性成分,将测量结果用作参考电压源逆变器输出电流。在低电压电网,有源滤波器可以使用的基础上,IGBTs逆变器的开关频率10千赫或更多。那些产生的谐波的逆变器很容易抑制与小被动过滤器。逆变器的几乎可以把被作为一种理想的可控的电压源等。然而，在几兆伏安电力级别的中压的应用中,如今的VSIs仅限于几百赫兹。现代高功率IGCTs可以操作的大约1千赫兹。因此,需要大规模无源滤波器,以清除脉动电流产生。逆变器的。此外,在快速控制方案不再逆变器的代表一个理想的电压源PWM调制生产因为dead-time相当大。在这个项目dead-beat算法快速发展VSIs PWM操作1该算法提高了跟踪性能和负载电流稳定的有源滤波器。通常,一个自由的谐波电流测量逆变电流。将被采样时同步的三角形尖端的载体。在这里,当前的收购是为了最大限度地减少了控制回路的延迟。现在谐波的包括时能计算和衰减逆变电流。因此,可以估计出摆脱了谐波的瞬时电流。From reference 3This report provides background information on electric power transmission and related policy issues. Proposals for changing federal transmission policy before the 111th Congress include S. 539, the Clean Renewable Energy and Economic Development Act, introduced on March 5, 2009; and the March 9, 2009, majority staff transmission siting draft of the Senate Energy and Natural Resources Committee. The policy issues identified and discussed in this report include:Federal Transmission Planning: several current proposals call for the federal government to sponsor and supervise large scale, on-going transmission planning programs. Issues for Congress to consider are the objectives of the planning process (e.g., a focus on supporting the development of renewable power or on a broader set of transmission goals), determining how much authority new interconnection-wide planning entities should be granted, the degree to which transmission planning needs to consider non-transmission solutions to power market needs, what resources theexecutive agencies will need to oversee the planning process, and whether the benefits for projects included in the transmission plans (e.g., a federal permitting option) will motivate developers to add unnecessary features and costs to qualify proposals for the plan.Permitting of Transmission Lines: a contentious issue is whether the federal government should assume from the states the primary role in permitting new transmission lines. Related issues include whether Congress should view management and expansion of the grid as primarily a state or national issue, whether national authority over grid reliability (which Congress established in the Energy Policy Act of 2005) can be effectively exercised without federal authority over permitting, if it is important to accelerate the construction of new transmission lines (which is one of the assumed benefits of federal permitting), and whether the executive agencies are equipped to take on the task of permitting transmission lines.Transmission Line Funding and Cost Allocation: the primary issues are whether the the federal government should help pay for new transmission lines, and if Congress should establish a national standard for allocating the costs of interstate transmission lines to ratepayers.Transmission Modernization and the Smart Grid: issues include the need for Congressional oversight of existing federal smart grid research, development, demonstration, and grant programs; and oversight over whether the smart grid is actually proving to be a good investment for taxpayers and ratepayers.Transmission System Reliability: it is not clear whether Congress and the executive branch have the information needed to evaluate the reliability of the transmission system. Congress may also want to review whether the power industry is striking the right balance between modernization and new construction as a means of enhancing transmission reliability, and whether the reliability standards being developed for the transmission system are appropriate for a rapidly changing power system.出自文献 3：该报告提供了背景资料的电力传输和相关的政策问题。改变政策建议111届前联邦传输539 .国会,包括清洁的可再生能源和经济开发条例,介绍了2009年3月5日,2009年3月9日,多数员工传输选址参议院的草案能源和自然资源委员会。确定的政策问题,讨论了这份报告包括:联邦传输计划:几个前沿建议呼吁联邦政府制定并监督大的规模,持续的传输规划中。国会的问题的目标是需要考虑的规划过程(例如,作出了重点扶持的可再生能源的发展上,或者在一个更广泛的套传动目标),决定新多的权力广泛关联规划实体应该被授予,传输计划的程度,需要考虑无输送解决电力市场的需要,有哪些资源执行机构需要检查计划的过程中,是否在项目包括福利传动方案(比如,一个联邦允许选择)鼓励开发者增加不必要的特点、成本晋级提案的计划。允许的输电线路:一个有争议的话题是美国联邦政府是否从美国应当承担的主要角色,来允许新的输送线。相关问题,包括国会是否要看管理和扩展栅格里,主要是一个国家或民族问题,是否在国家权威机构的电力输送网的可靠度(国会成立能源政策法案的2005)可以有效地执行联邦权威没有在允许的情况下,如果它是很重要的,加快建设新的输电线路(假定的好处之一),联邦政府的允许是否有执行机构的任务,以允许输电线路。传输线的资金和成本分摊:主要问题是否有联邦政府将帮助支付新的传输线,如果国会不应确立一个全国范围的成本分配标准地方纳税人输电线路对号州际公路。传输现代化和聪明的网格:课题包含需要国会忽略了现有的联邦聪明的网格研究、发展、示范,并给予和监管程序;实际上是聪明阀是否证明自己是一个不错的投资纳税人和地方纳税人。传动系统可靠性:不清楚国会和行政部门有所需的信息的可靠性进行了评价的传输系统。国会也可能要检讨电力行业是否之间找到平衡点现代化建设、新建设作为一种手段,提高传输的可靠性,以及处理可靠性的标准被开发出来用于传动系统适合一个快速变化的电力系统。Page2 Requirements of an Electric Supply System(供电系统需求)From reference1Connections to external 330 kV power grids are provided using an open 330 kV switchyard. The plant is connected to the Lithuanian power grid using two transmission lines L-454 and L-453, 330 kV each, to the Belorussian power grid using three transmission lines L-450, L-452 and L-705, and to the Latvian power grid using one transmission line L-451.Connections to external power grids at 110 kV are provided using the first section of the open 110 kV switchyard. The plant is connected to the Lithuanian power grid using one transmission line “Zarasai” 110 kV, and to the Latvian power grid using one transmission line L-632. Connections between the open switchyards at 330 kV and 110 kV are established using two coupling autotransformers AT-1 and AT-2, types ATDCTN- 200000/330. Power of each autotransformer is equal to 200 MV×A. The autotransformers have a device for voltage regulation under load. The device type is RNOA-110/1000. 15 positions are provided to regulate voltage in a range (115 ± 6) kV.The open 330 kV switchyard is designed using "4/3" principle (four circuit breakers per three connections) and consists of two sections. Circuit breakers are placed in two rows. The first section of the open switchyard 110 kV is designed using “Double system of buses with bypass” structure. The second section of open switchyard 110 kV is connected to the first section through two circuit breakers C101 and C102. The second section has the same design as the first one. The following transmission lines are connected to the second section: L-Vidzy, L-Opsa, L-Statyba, LDuk Ötas. These transmission lines are intended for district power supplies, so they are not essential for electric power supply for the plant in-house operation.Air circuit breakers of VNV-330/3150A type are used in the open 330 kV switchyard. Air circuit breakers of VVBK-110B-50/3150U1 type are used in open switchyard 110 kV. To supply power loads on voltage level 330 kV and 110 kV, aerial transmission lines are used. Electrical connections of external grids 110 and 330 kV are presented in Fig. 8.1.Keywords: transmission lines出自文献 1：连接到外部330千伏电网使用一个公开的330千伏提供送变电。植物被连接到立陶宛电网输电线路使用两L-454和L-453,需要330名千伏各电网的使用三输电线路,L-450 L-452和L-705,拉脱维亚电网输电线路L-451使用。连接到外部力量,提供110千伏网格使用第一部分开放的110千伏送变电。植物被连接到立陶宛电网输电线路使用110千伏和拉脱维亚电网输电线路L-632使用。打开开关之间的连结在330千伏及110千伏建立了耦合自耦变压器 AT-1使用两AT-2、类型ATDCTN,200000/330。能对各自耦变压器等于200 MV。自耦变压器有一个装置的在荷载作用下,电压调整。是该设备类型RNOA-110/1000。15个新职位提供给调节电压范围(115±6)千伏。开放330千伏送变电设计使用“4/3”的原则(4断路器每三连接),由两个部分。断路器被安置在两排。第一部分开放送变电110千伏使用“双系统设计的公车搭桥”的结构。第二部分开放送变电110千伏被连接到第一部分通过两个断路器C101和C102。第二部分有相同的设计的第一次。下面的输电线路连接到第二条L-Vidzy,L-Opsa L-Statyba,以LDuk,。这些输电线路的目的是为地区电力供应,所以他们不是必需的电力供应植物内部运作。空气断路器的类型VNV-330/3150A用于开放330千伏送变电。空气断路器的使用VVBK-110B-50/3150U1类型在公开送变电110千伏。提供电力负载电压水平330千伏及110千伏、空中输电线路使用。电气连接外部网格110、330千伏了图8.1。关键词：输电线From reference 2AbstractThis paper addresses sustainability criteria and the associated indicators allowingoperationalization of the sustainability concept in the context of electricity supply. The criteria and indicators cover economic, environmental and social aspects. Some selected results from environmental analysis, risk assessment and economic studies are shown. These studies are supported by the extensive databases developed in this work. The applications of multi-criteria analysis demonstrate the use of a framework that allows decision-makers to simultaneously address the often conflicting socio-economic and ecological criteria. “EnergyGame”, the communication-oriented software recently developed by the Paul Scherrer Institute (PSI), provides the opportunity to integrate the central knowledge-based results with subjective value judgments. In this way a sensitivity map of technology choices can be constructed in an interactive manner. Accommodation of a range of perspectives expressed in the energy debate, including the concept of sustainable development, may lead to different internal rankings of the options but some patterns appear to be relatively robust.IntroductionThe public, opinion leaders and decision-makers ask for clear answers on issues concerning the energy sector and electricity generation in particular. Is it feasible to phase out nuclear power in countries extensively relying on nuclear electricity supply and simultaneously reduce greenhouse gas emissions? What are the environmental and economic implications of enhanced uses of cogeneration systems, renewable sources and heat pumps? How do the various energy carriers compare with respect to accident risks? How w