【正文】 10 volts. The current inputs must be converted to voltages by resistive shunts. As the normal current transformer secondary currents may be as hundreds of amperes, shunts of resistance of a few milliohms are needed to produce the desired voltage for Analog to Digital Converter (ADC). An alternative arrangement would be to use an auxiliary current transformer to reduce the current to lower level. An auxiliary current transformer serves another function: that of providing electrical isolation between the min CT secondary and the puter input system.Since the digital puter can be programmed to perform several functions as long as it has the input and output signals needed for those functions. It is simple matter to the relaying puter to do many other substation tasks, for example, measuring and monitoring flows and voltages in transformers and transmission lines, controlling the opening and closing of circuit breakers and switches, providing backup for other devices that have failed, are functions that can be taken over by the relaying puter. With the program ability and munication capability, the puterbased relaying offers yet another possible advantage that is not easily realizable in a conventional system. This is the ability to change the relay characteristics (settings) as the system conditions warrant it. With reasonable prospects of having affordable puterbased relaying which can be dedicated to single protection function, attention soon turned to the opportunities offered by puterbased relaying to integrate them into a substation, perhaps even a systemwide network. Integrated puter systems for substations which handle relaying, monitoring, and control tasks offer novel opportunities for improving overall system performance. Computer relayingThe electric power industry has been one of the earliest users of the digital puter as a fundamental aid in the various design and analysis aspects of its activity. Computerbased systems have evolved to perform such plex tasks as generation control, economic dispatch (treated in chapter 11)and loadflow analysis for planning and operation , to name just a few application areas. research efforts directed at the prospect using digital puters to perform the tasks involved in power system protection date back to the miensixties and were motivated by the emergence of processcontrol puters a great deal of research is going on in this field, which is now referred to as puter relaying. Up to the early 1980s there had been no mercially availability protection systems offering digital puterbased relays. However, the availability of microprocessor technology has provided an impetus to puter relaying.*Microprocessors used as a replace*and solid state relays non provide a number of advantages while meeting the basic protection philosophy requirement of decentralization.There are many perceived benefits of a digital relaying system:1. Economics: with the steady decrease in cost of digital hardware, coupled with the increase in cost of conventional relaying. It seems reasonable to assume that puter relaying is an attractive alternative. Software development cost can be expected to be evened out by utilizing economies of scale in producing microprocessors dedicated to basic relaying tasks. 2. Reliability: a digital system is continuously active providing a high level of a selfdiagnosis to detect accidental failures within the digital relaying system.3. Flexibility: revisions or modifications made necessary by changing operational conditions can be acmodated by utilizing the programmability features of a digital system. This would lead to reduced inventories of parts for repair and maintenance purposes4. System interaction: the availability of digital hardware that monitors continuously the system performance at remote substations can enhance the level of information available to the control center. Post fault analysis of transient data can be performed on the basis of system variables monitored by the digital relay and recorded by the peripherals. The main elements of a digital puterbased relay are in。3氣象資料 本廠所在地區(qū)的年最高溫度為，年平均氣溫為，年最低氣溫為，年最熱月平均最高氣溫為，年最熱平均氣溫為，當地主導風向為東北風，年雷暴數為20。為滿足工廠二級負荷可采用高壓線由鄰近的單位取得備用電源。該干線的的導線型號LGJ150，導線為等邊三角形排列，線距為2m；干線首端所裝設的高壓斷路器斷流容量為500MVA。該紡織廠中鍛工車間、紡紗車間、軟水站是二級負荷，其余均為三級負荷。該廠有二級負荷這三級負荷。另外，我也向為本次設計提供資料的校圖書館及在本次設計過程中給予我?guī)椭睦蠋熀屯瑢W表示衷心的感謝。在此我要特別要感謝趙順東、段曉明老師，他們?yōu)槲覀儾晦o辛苦的點撥，給我們解決了不少課題中的疑難問題，提供了很多指導性的意見?！甭尻柪砉W院畢業(yè)設計論文謝 辭在老師的精心指導下，經過2個多月的努力，我終于順利完成了本次設計任務。結　論本次畢業(yè)是對紡織廠供配電系統的設計，通過完成負荷計算 、主接線設計、電源進線及工廠高壓配電線路的設計、短路計算、高低壓電氣設備選擇、變電站幾點保護和防雷接地，使得一個完成的工廠供配電系統呈現在我們的面前。接地干線均采用25mm4mm的鍍鋅扁鋼。管間用40mm4mm的鍍鋅扁鋼焊接相連。（3）在380V低壓架空出線桿上，裝設保護間隙，或將其絕緣子的鐵腳接地，用以防護沿低壓架空線侵入的雷電波。（2）在10kV高壓配電室內裝設GG1A（F）54型高壓開關柜，其中配有FS410型避雷器，靠近主變壓器。 雷電侵入波的防護（1）在10kV電源進線的終端桿上裝設FS410型閥式避雷器。 變電所的防雷保護 直擊雷防護 在變電所屋頂裝設避雷針或避雷帶，并引出兩根接地線與變電所公共接地裝置相連。當線路上出現危及設備絕緣的雷電過電壓時，避雷器的火花間隙就被擊穿，或由高阻變?yōu)榈妥瑁惯^電壓對大地放電，從而保護了設備的絕緣。避雷器是用來防止雷電產生的過電壓波沿線路侵入變配電所或其它建筑物內，以免危及被保護設備的絕緣。接閃的金屬帶稱為避雷帶。接閃的金屬稱為避雷針。表66 變電所車間低壓斷路器型號低壓電流互感器型號和變比 車間變電所鍛工車間DZ20100/3（20/5）紡紗車間DZ20630/3（600/5）制條車間DZ20630/3（600/5）軟水站DZ20200/3（150/5） 車間變電所倉庫出線DZ20400/3（300/5）機修車間DZ20100/3（50/5）辦公樓DZ20100/3（50/5） 車間變電所織工車間DZ201250/3（700/5）染工車間DZ20630/3（700/5）食堂車間DZ20100/3（60/5） 車間變電所鍋爐房DZ20400/3（300/5）水泵房DZ20200/3（200/5）油泵房DZ20100/3（50/5）化驗區(qū)DZ20100/3（100/5） 車間變電所生活區(qū)DZ20400/3（400/5）第7章 防雷與接地設計防雷的設備主要有接閃器和避雷器。（電流比為400/5）,低壓斷路器DZ20400/3。所以選擇低壓斷路器DW15400，低壓刀開關HD13400/30，（電流比為400/5）均滿足負荷電流的要求。，（電流比為100/5）低壓斷路器DZ20100/3。，（電流比為200/5）低壓斷路器DZ20200/3。該車間變電所下屬鍋爐房、水泵房、油泵房、化驗區(qū)。 車間變電所。,（電流比為700/5），低壓斷路器DZ20630/3。該車間變電所下屬織工車間、染工車間、食堂。 車間變電所 。，（電流比為50/5），低壓斷路器為DZ20100/3。 該車間變電所下屬機修車間、倉庫、辦公樓。 車間變電所 。，（電流比為600/5），低壓斷路器DZ20630/3。，（電流比為20/5），低壓斷路器DZ20100/3。根據上述選型得出10kV側一次設備表如表65表65