CHAPTER 1第一章 ELECTRICAL POWER SYSTEM OVERCURRENTS電力系統(tǒng)過電流 This manual establishes the criteria for design, coordination, and construction of power systems for military projects.本手冊規(guī)定了設(shè)計(jì)，協(xié)調(diào)的標(biāo)準(zhǔn)，和軍事項(xiàng)目的電力系統(tǒng)的建設(shè)。 A secondary purpose is to acquaint designers with the general applications, philosophies, and purposes for the selection, calibration, setting, and testing of protective devices.次要的目的是與一般的應(yīng)用程序，哲學(xué)了解設(shè)計(jì)師和甄選，校準(zhǔn)的目的，設(shè)置和保護(hù)裝置的測試。 1-2. 1-2。 Scope范圍 This manual describes protection techniques for electrical power supply and distribution systems.本手冊介紹了電力供應(yīng)和分配系統(tǒng)的保護(hù)技術(shù)。 Guidance is included for coordination techniques and selection of protective devices.指導(dǎo)，協(xié)調(diào)，是包括技術(shù)和保護(hù)裝置的選擇。 1-3. 1-3。 References參考文獻(xiàn) Appendix A contains a list of references used in this document.附錄A本文件中使用的引用列表。 1-4. 1-4。 Electrical power systems電力系統(tǒng) Electric power systems consist of four major categories: generating stations, transmission lines, distribution lines, and utilization systems.電力系統(tǒng)包括四大類：發(fā)電廠，輸電線路，配電線路，并利用系統(tǒng)。 The electric power system industry converts and transports energy for utilization by numerous industrial, commercial, and residential customers.電力系統(tǒng)行業(yè)的轉(zhuǎn)換和傳輸，利用眾多工業(yè)，商業(yè)和住宅用戶的能源。 One of the largest users of electric energy in the United States is the US Government.對在美國電能的最大用戶之一，是美國政府。a.字母a. Generation.代。 The majority of electrical power produced in the United States is generated by steam-turbine plants.在美國電力生產(chǎn)所產(chǎn)生的大多數(shù)是蒸汽渦輪機(jī)工廠。 Hydro-electric generation accounts for only a small percentage because most available water sources have already been placed into service.水電只占很小的百分比占發(fā)電，因?yàn)榇蠖鄶?shù)可用水源已投入服務(wù)上。 Gas-turbines are used primarily for peaking during short periods of high demand.燃?xì)鉁u輪機(jī)主要用于在高需求的短期見頂。 Fuel for steam-turbine plants is, for the most part, coal or nuclear.燃油蒸汽渦輪機(jī)工廠是，在大多數(shù)情況下，煤電或核。 b.灣 Transmission lines.傳輸線。 The voltage rating of large generators employed at primary generating stations ranges from 13.8kV to 24kV.對小發(fā)電站從13.8kV到24KV級不等就業(yè)大型發(fā)電機(jī)電壓等級。 Generator voltage is stepped up to transmission voltage level using transformers.發(fā)電機(jī)電壓是加強(qiáng)輸電電壓等級變壓器使用。 Transmission voltage levels in the United States range from 115kV to 765kV.在美國范圍內(nèi)傳輸從115kV電壓等級為765kV。 Standard voltages are 115kV, 138kV, 230kv, 345kV, 500kV, and 765kV.標(biāo)準(zhǔn)電壓115kV，138kV，230kv，345kV，500千伏和765kV。 c.角 Distribution lines.配電線路。 Transmission line voltage is stepped down to lower levels at main substations.輸電線路電壓下臺水平較低，主要變電站。 These lower voltage levels range from about 34.5kV to 138kV.這些更低電壓范圍從34.5kV至138kV。 Distribution substations further step the voltage down to distribution voltage level which is in the range of 5kV to 34.5kV.配電站進(jìn)一步加強(qiáng)了電壓下降到電壓水平分布在5kV的范圍是34.5kV。 Popular standard voltages at the distribution level are 4.16kV 12.47kV, 13.2kV, 13.8kV, and 34.5kV.在分配水平受歡迎的標(biāo)準(zhǔn)電壓4.16kV 12.47kV，13.2kV，13.8kV，和34.5kV。 d. d. Utilization.利用。 Distribution transformers are used to step the distribution voltage down to utilization levels, usually at 600V.配電變壓器用于步驟分配電壓下降到利用水平，通常在600V的。 Standard utilization voltages include 480Y/277V, 460V, 208Y/120V, 240V, and 120V.標(biāo)準(zhǔn)利用率電壓包括480Y/277V，460伏，208Y/120V，240伏，和120V。 Higher-level voltages, such as 6.9kv and 4.16kV, are popular standard voltages for supplying large industrial motor loads.更高層次的電壓，如6.9kv和4.16kV，為大工業(yè)提供電機(jī)負(fù)載流行的標(biāo)準(zhǔn)電壓。 提問者： gz_fung - 一級