课程设计35KV电网继电保护设计——距离保护.doc

35kv电网继电保护课程设计摘 要本次课程设计的题目是35KV电网继电保护设计距离保护。主要任务是为保证电网的安全运行,需要对电网配置完善的继电保护装置.根据该电网的结构、电压等级、线路长度、运行方式以及负荷性质的要求，给35KV的输电线路设计合适的继电保护。根据给定的相关数据，首先设计了输电线路图，然后进行整定计算。根据对距离保护I，II， III段保护的整定计算，熟悉距离保护的基本原理。根据这次设计总结距离保护的优缺点。并对这次设计进行总结。关键词：35kv继电保护、整定计算、故障分析、短路电流计算第一章 概论21.1继电保护的基本概念2第二章 距离保护的要求32.1 电力系统距离保护32.1.1距离保护概念及适用范围32.1.2距离保护的时限特性32.2 阻抗继电器4第三章 距离保护的计算53.1 系统电路图53.2 短路电流计算53.3 距离保护的整定83.4本设计的具体计算133.4.1距离保护I段的整定计算133.4.2距离保护II段的整定计算和校验133.4.3距离保护III段的整定计算和校验14第四章 距离保护的评价154.1距离保护的优缺点和应用范围15第五章 设计心得16参考文献17第一章 概论1.1继电保护的基本概念 在电力系统运行中，外界因素（如雷击、鸟害等）、内部因素（绝缘老化，损坏等）及操作等，都可能引起各种故障及不正常运行的状态出现，常见的故障有：单相接地；三相接地；两相接地；相间短路；短路等。 电力系统非正常运行状态有：过负荷，过电压，非全相运行，振荡，次同步谐振，同步发电机短时失磁异步运行等。 电力系统继电保护和安全自动装置是在电力系统发生故障和不正常运行情况时，用于快速切除故障，消除不正常状况的重要自动化技术和设备。电力系统发生故障或危及其安全运行的事件时，他们能及时发出告警信号，或直接发出跳闸命令以终止事件。 继电保护的基本任务： （1）自动迅速，有选择的跳开特定的断路器（2）反映电气元件的不正常运行状态 电力系统对继电保护的基本要求 ：速动性，选择性，灵敏性,可靠性。第二章 距离保护的要求2.1 电力系统距离保护2.1.1距离保护概念及适用范围距离保护是反应故障点至保护安装地点之间的距离（或阻抗）。并根据距离的远近而确定动作时间的一种保护装置。该装置的主要元件为距离（阻抗）继电器，它可根据其端子上所加的电压和电流测知保护安装处至短路点间的阻抗值，此阻抗称为继电器的测量阻抗。当短路点距保护安装处近时，其测量阻抗小，动作时间短；当短路点距保护安装处远时，其测量阻抗增大，动作时间增长，这样就保证了保护有选择性地切除故障线路。 用电压与电流的比值(即阻抗)构成的继电保护，又称阻抗保护，阻抗元件的阻抗值是接入该元件的电压与 电流的比值：U/I=Z，也就是短路点至保护安装处的阻抗值。因线路的阻抗值与距离成正比，所以叫距离保护或阻抗保护。距离保护分为接地距离保护和相间距离保护等。 距离保护分的动作行为反映保护安装处到短路点距离的远近。与电流保护和电压保护相比，距离保护的性能受系统运行方式的影响较小。距离保护分为接地距离保护和相间距离保护等。距离保护适用于35kv及以上的电压等级电路。2.1.2距离保护的时限特性距离保护一般都作成三段式，第1段的保护范围一般为被保护线路全长的8085，动作时间为保护装置的固有动作时间。第段的保护范围需与下一线路的保护定值相配合，一般为被保护线路的全长及下一线路全长的3040，其动作时限要与下一线路距离保护第1段的动作时限相配合，一般为05s左右。第段为后备保护，其保护范围较长，包括本线路和下一线路的全长乃至更远，其动作时限按阶梯原则整定。2.2 阻抗继电器阻抗继电器针对的是线路的阻抗而言，故而分析线路阻抗是非常必要的。通常起动元件采用过电流继电器或阻抗继电器。为了提高元件的灵敏度,也可采用反应负序电流或零序电流分量的复合滤过器来作为起动元件。第三章 距离保护的计算3.1 系统电路图图3-13.2 短路电流计算当K2点发生短路时，短路电流的计算如下：最大运行方式下，K2点短路的等值电路图 图3-2-1 等值简化电路图图3-2-2最大运行方式下k2短路时，A电站、C电站到短路点的转移电抗分别为：XAK=5.333/2+0.75=3.417XCK=0.292+0.876+0.75+4/2=3.918A电站、C电站到短路点的计算电抗为：XJSA=3.417×(2×3/0.8)/100=0.256 XJSC=3.918×(2×4/0.8)/100=0.391查运算曲线图，得A、C短路电流标幺值为：IA0.2*=3.175 IC0.2*=2.412 有名值为：IAK0.2=3.175×15/(37×)=0.74KA ICK0.2=2.412×10/(37×）=0.38KA最小运行方式下，K2点短路的等值电路图图3-2-3等值简化电路图：图3-2-4最小运行方式下k2短路时，A电站、C电站到短路点的转移电抗分别为XAK=0.75+5.333=6.083XCK=0.292+0.876+0.75+4=5.917计算电抗为XJSA=6.083×3.75/100=0.228 XJSC=5.917×5/100=0.30查运算曲线图，得A、C短路电流标幺值为IB0.2*=3.433 IC0.2*=2.950 有名值为IAK0.2=3.433×3.75/(37×）=0.201KA ICK0.2=2.950×5/(37×）=0.23KA按照上述方法，可求得K3、K4、K5、K6、K7、K8点短路时相应的短路电流。3.3 距离保护的整定 （1）距离I段的整定距离保护段无延时的速动段它应该只反映本线路的故障，下级出口处发生短路故障时应可靠不动作，所以测量元件的阻抗整定应该躲过本线路末端短路时的测量阻抗来整定。即其中<1因为距离保护是欠量保护，考虑到继电器误差、互感器误差和参数测量等误差等因素一般取0.80.85是被保护线路的长度是被保护线路单位长度的正序阻抗（2） 距离段的整定1、分支电路对测量阻抗的影响。在距离保护段整定时，类同于电流保护，应考虑分支电路对测量阻抗的影响，如图所示。 （a）助增分支电路对测量阻抗的影响（b）外汲分支电路对测量阻抗的影响图中k1点发生三相短路时，保护1处的测量阻抗为 式中：母线B与短路点之间线路的正序阻抗；：分支系数。在助增分支电路和外汲分支电路中不同。2、段的整定阻抗。距离保护段的整定阻抗，应按照以下两个原则进行计算。（1）与相邻线路距离保护段相配合。距离段的整定阻抗为： 式中，为可靠系数，一般取0.8；（2）与相邻变压器的快速保护相配合。距离段的整定阻抗为： 为可靠系数，考虑变压器阻抗误差较大，一般取0.70.75。当被保护线路末端母线上既有出线又有变压器时，距离段的整定阻抗应分别按上述两种情况计算，取其中的较小者作为整定阻抗。3、灵敏度校验距离保护段，应能保护线路的全长，本线路末端短路时，应有足够的灵敏度。考虑到各种误差因素，要求灵敏系数应满足 如果不满足要求，则距离保护1的段应改为与相邻元件的保护段相配合，计算方法与上面类似。4、动作时间的整定距离保护段的动作时间，应与之配合的相邻元件保护动作时间大一个时间级差，即 式中为与本保护配合的相邻元件保护段（x为或段）最大的动作时间。（3）距离段的整定1、段的整定阻抗。距离保护第段的整定阻抗，按以下几个原则计算：（1）按与相邻下级线路距离保护段配合时，段的整定阻抗为 可靠系数的取法与段整定中类似，分支系数应取各种情况下的最小值。如果与相邻下级线路距离保护段配合灵敏系数不满足要求，则应改为与相邻下级线路距离保护的段相配合。（2）按与相邻下级变压器的电流、电压保护配合整定。定值计算为： 式中为电流、电压保护的最小保护范围对应的阻抗值。（3）按躲过正常运行时的最小负荷阻抗整定。当线路上的负荷最大且母线电压最低时，负荷阻抗最小，其值为 式中为正常运行母线电压的最低值；为被保护线路最大负荷电流；为母线额定电压。参照过电流保护的整定原则，考虑到电动机自启动的情况下，保护段必须立即返回的要求，若采用全阻抗特性，则整定值为：式中为可靠系数，一般取1.21.25；为电动机自启动系数，取1.52.5；为阻抗测量元件（欠量动作）的返回系数，取1.151.25。若采用方向圆特性，必须考虑动作阻抗随阻抗角的变化，由躲开的负荷阻抗换算成整定阻抗值，整定阻抗可由下式给出,式中为整定阻抗的阻抗角；为负荷阻抗的阻抗角。按上述三个原则进行计算，取其中的较小者作为距离段的整定阻抗。2、灵敏度校验。距离保护的段，既作为本线路、段保护的近后备，又作为相邻下级设备保护的远后备，灵敏度应分别进行校验。作为近后备时，按本线路末端短路校验，计算式为作为远后备时，按相邻设备末端短路校验，计算式为式中为相邻设备（线路、变压器等）的阻抗；为分支系数最大值，以保证在各种运行方式下保护动作的灵敏性。3、动作时间的整定。距离保护段的动作时间，应比与之配合的相邻设备保护动作时间大一个时间级差，但考虑到距离段一般不经历震荡闭锁，其动作时间不应小于最大的震荡周期（1.52s）。3.4本设计的具体计算3.4.1距离保护I段的整定计算(1) 动作阻抗对输电线路，按躲过本线路末端短路来整定,则取=0.85，所以=0.85*10*0.4=3.4(2)动作时限距离保护段的动作时限是由保护装置的继电器固有动作时限决定，人为延时为零，即=0s。3.4.2距离保护II段的整定计算和校验(1)动作阻抗：按下列三个条件选择。与相邻线路34的保护的段配合式中，取=0.85, =0 .8，为保护2的段末端发生短路时对保护2而言的最小分支系数。当保护2的段末端发生短路时，分支系数为：=I12/I34=1于是(2)动作时间，与相邻保护2的段配合，则t1"=t2'+t=0.5 s它能同时满足与相邻线路34保护配合的要求。(3) 灵敏性校验：/=9.52/3.4=2.8>1.5, 满足要求。3.4.3距离保护III段的整定计算和校验(1)动作阻抗：按躲开最小负荷阻抗整定；Kzq=1,=1.15,=0.83， =1.5，I =1.75KAZL·min=0.9Ue/1.732If·max=0.9×35/1.732×1.75=10.39=（ ZL·min）/ ( Kzq)=(0.83*10,39) /(1.5*1.15)=5(2)动作时间：断路器1的动作时间为：= +t=1.5+0.5=2 s断路器2的动作时间为：t2= +t=2.0+0.5=2.5 s取其中较长者，于是,断路器1的动作时间为：t1= +t=2.0+0.5=2.5 s(3)灵敏性校验： 本线路末端短路时的灵敏系数为： /Z12=5/0=>1.5 ，满足要求。第四章 距离保护的评价4.1距离保护的优缺点和应用范围主要优点：能满足多电源复杂电网对保护动作选择性的要求；阻抗继电器是同时反应电压的降低和电流的增大而动作的，因此距离保护较电流保护有较高的灵敏度。其中段距离保护基本不受运行方式的影响，而、段受系统运行变化的影响也较电流保护要小一些，保护区域比较稳定。主要缺点：不能实现全线瞬动。对双侧电源线路，将有全线的3040的第段时限跳闸，这对稳定有较高要求的超高压远距离输电系统来说是不能接受的。阻抗继电器本身较长复杂，还增设了振荡闭锁装置，电压断线闭锁装置，因此距离保护装置调试比较麻烦，可靠性也相对低些。应用范围：对不要求全线速动的线路，可作为主保护，否则，可作为相间或接地故障的后备保护。第五章 设计心得本次设计是针对35KV输电线路在双回路情况下进行的分析计算和整定的。在进行设计时首先要设计线路图。然后根据设计要求进行距离保护的整定，并且对其进行灵敏度较验。我认为，在这次的课程设计中，在收获知识的同时，还收获了阅历，收获了成熟，在此过程中，我通过查找大量资料，与同学探讨，以及不懈的努力，不仅培养了独立思考、动手操作的能力，在各种其它能力上也都有了提高。更重要的是，通过本次课程设计，我学会了很多学习的方法。而这是日后最实用的，真的是受益匪浅。要面对社会的挑战，只有不断的学习、实践，再学习、再实践。此次课程设计能顺利的完成与同学和老师的帮助是分不开的，在对某些知识模棱两可的情况下，多亏有同学的热心帮助才可以度过难关；更与老师的悉心教导分不开，在有解不开的难题时，多亏老师们的耐心指导才使设计能顺利进行。很感谢学校和老师给我们安排了这次课程设计，让我真正感受到的是合作的重要，许多时候都是组员的讨论，老师的指导中的一句半句启发了我，就出现的让人欣喜的结果；理论知识同样很重要，有些问题都是由于基础知识掌握不好才出现的。在此衷心再次感谢老师的悉心教导和各位同学的帮助！参考文献待添加的隐藏文字内容21 崔家佩.电力系统继电保护及安全自动整定计算.北京：中国电力出版社，20062 张保会，尹项根.电力系统继电保护（第二版）. 北京：中国电力出版社,20093 许建安.继电保护整定计算. 北京：中国水利水电出版社，20034 李光琦.电力系统暂态分析（第三版）.北京：中国电力出版社，20075 贺家李. 电力系统继电保护原理（第四版）. 中国电力出版社.Employment tribunals sort out disagreements between employers and employees.You may need to make a claim to an employment tribunal if:· you don't agree with the disciplinary action your employer has taken against you· your employer dismisses you and you think that you have been dismissed unfairly.For more information about dismissal and unfair dismissal, see Dismissal.You can make a claim to an employment tribunal, even if you haven't appealed against the disciplinary action your employer has taken against you. However, if you win your case, the tribunal may reduce any compensation awarded to you as a result of your failure to appeal.Remember that in most cases you must make an application to an employment tribunal within three months of the date when the event you are complaining about happened. If your application is received after this time limit, the tribunal will not usually accept it.If you are worried about how the time limits apply to you, take advice from one of the organisations listed under Further help.Employment tribunals are less formal than some other courts, but it is still a legal process and you will need to give evidence under an oath or affirmation.Most people find making a claim to an employment tribunal challenging. If you are thinking about making a claim to an employment tribunal, you should get help straight away from one of the organisations listed under Further help.If you are being represented by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out of your compensation if you win the case. This is known as a damages-based agreement. In England and Wales, your solicitor can't charge you more than 35% of your compensation  if you win the case.If you are thinking about signing up for  a damages-based agreement, you should make sure you're clear about the terms of the agreement. It might be best to get advice from an experienced adviser, for example, at a Citizens Advice Bureau.  To find your nearest CAB, including those that give advice by e-mail, click on nearest CAB.For more information about making a claim to an employment tribunal, see Employment tribunals.The (lack of) air up there Watch mCayman Islands-based Webb, the head of Fifa's anti-racism taskforce, is in London for the Football Association's 150th anniversary celebrations and will attend City's Premier League match at Chelsea on Sunday."I am going to be at the match tomorrow and I have asked to meet Yaya Toure," he told BBC Sport."For me it's about how he felt and I would like to speak to him first to find out what his experience was."Uefa has opened disciplinary proceedings against CSKA for the "racist behaviour of their fans" during City's 2-1 win.Michel Platini, president of European football's governing body, has also ordered an immediate investigation into the referee's actions.CSKA said they were "surprised and disappointed" by Toure's complaint. In a statement the Russian side added: "We found no racist insults from fans of CSKA."Age has reached the end of the beginning of a word. May be guilty in his seems to passing a lot of different life became the appearance of the same day; May be back in the past, to oneself the paranoid weird belief disillusionment, these days, my mind has been very messy, in my mind constantly. Always feel oneself should go to do something, or write something. Twenty years of life trajectory deeply shallow, suddenly feel something, do it.一字开头的年龄已经到了尾声。或许是愧疚于自己似乎把转瞬即逝的很多个不同的日子过成了同一天的样子；或许是追溯过去，对自己那些近乎偏执的怪异信念的醒悟，这些天以来，思绪一直很凌乱，在脑海中不断纠缠。总觉得自己自己似乎应该去做点什么，或者写点什么。二十年的人生轨迹深深浅浅，突然就感觉到有些事情，非做不可了。The end of our life, and can meet many things really do?而穷尽我们的一生，又能遇到多少事情是真正地非做不可？During my childhood, think lucky money and new clothes are necessary for New Year, but as the advance of the age, will be more and more found that those things are optional; Junior high school, thought to have a crush on just means that the real growth, but over the past three years later, his writing of alumni in peace, suddenly found that isn't really grow up, it seems is not so important; Then in high school, think don't want to give vent to out your inner voice can be in the high school children of the feelings in a period, but was eventually infarction when graduation party in the throat, later again stood on the pitch he has sweat profusely, looked at his thrown a basketball hoops, suddenly found himself has already can't remember his appearance.童年时，觉得压岁钱和新衣服是过年必备，但是随着年龄的推进，会越来越发现，那些东西根本就可有可无；初中时，以为要有一场暗恋才意味着真正的成长，但三年过去后，自己心平气和的写同学录的时候，突然就发现是不是真正的成长了，好像并没有那么重要了；然后到了高中，觉得非要吐露出自己的心声才能为高中生涯里的懵懂情愫划上一个句点，但毕业晚会的时候最终还是被梗塞在了咽喉，后来再次站在他曾经挥汗如雨的球场，看着他投过篮球的球框时，突然间发现自己已经想不起他的容颜。Originally, this world, can produce a chemical reaction to an event, in addition to resolutely, have to do, and time.原来，这个世界上，对某个事件能产生化学反应的，除了非做不可的坚决，还有，时间。A person's time, your ideas are always special to clear. Want, want, line is clear, as if nothing could shake his. Also once seemed to be determined to do something, but more often is he backed out at last. Dislike his cowardice, finally found that there are a lot of love, there are a lot of miss, like shadow really have been doomed. Those who do, just green years oneself give oneself an arm injection, or is a self-righteous spiritual.一个人的时候，自己的想法总是特别地清晰。想要的，不想要的，界限明确，好像没有什么可以撼动自己。也曾经好像已经下定了决心去做某件事，但更多的时候是最后又打起了退堂鼓。嫌恶过自己的怯懦，最终却发现有很多缘分，有很多错过，好像冥冥之中真的已经注定。那些曾经所谓的非做不可，只是青葱年华里自己给自己注射的一支强心剂，或者说，是自以为是的精神寄托罢了。At the moment, the sky is dark, the air is fresh factor after just rained. Suddenly thought of blue plaid shirt; Those were broken into various shapes of stationery; From the corner at the beginning of deep friendship; Have declared the end of the encounter that haven't start planning. Those years, those days of do, finally, like youth, will end in our life.此刻，天空是阴暗的，空气里有着刚下过雨之后的清新因子。突然想到那件蓝格子衬衫；那些被折成各种各样形状的信纸；那段从街角深巷伊始的友谊；还有那场还没有开始就宣告了终结的邂逅计划那些年那些天的非做不可，终于和青春一样，都将在我们的人生中谢幕。Baumgartner the disappointing news: Mission aborted. r plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.The supersonic descent could happen as early as Sunda.The weatheThe balloon will slowly drift to the edge of space at 120,000 feet ( Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform.Below, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, he'll be traveling fast, so despite the distance, it will not be like diving into the deep end of a pool. It will be like he is diving into the shallow end. Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to Earth. But this will not be enough to stop him completely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes it's not needed. Instead, he plans to deploy his 270-square-foot (25-square-meter) main chute at an altitude of around 5,000 feet (1,524 meters).In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everything goes as planned, it won't. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters).cause there