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How Electricity Is Delivered To Consumers

Source: https://www.eia.gov/Energyexplained/index.cfm?page=electricity_delivery

(本文僅做翻譯練習之用，粗體字為練習時有感窒礙處，如有錯誤請不吝指正)

Electricity is delivered to consumers through a complex network

電力透過複雜網絡輸送抵用電者

Electricity is generated at power plants and moves through a complex system, sometimes called the grid, of electricity substations, transformers, and power lines that connect electricity producers and consumers. Most local grids are interconnected for reliability and commercial purposes, forming larger, more dependable networks that enhance the coordination and planning of electricity supply.

       電力由電廠製造，於變電站、變壓器以及連接發電者與用電者的電纜線組成的複雜系統──或稱為電網──上流動。出於可依賴性以及商業目的的考量，大部分本地端的電網會被相互連接以產生更大型、更可靠的網絡，有益網絡的協調性以及電力供輸的規劃。

In the United States, the entire electricity grid consists of hundreds of thousands of miles of high-voltage power lines and millions of miles of low-voltage power lines with distribution transformers that connect thousands of power plants to hundreds of millions of electricity customers all across the country.

        在美國，整個電網包含數十萬浬的高壓電纜以及數百萬浬的低壓電纜，配合著變壓器連接數以千計的發電廠以及整個國家裡的數百萬消費者。

The stability of the electricity grid requires the electricity supply to constantly meet electricity demand, which in turn requires coordination of numerous entities that operate different components of the grid. The U.S. electricity grid consists of three large interconnected systems that operate to ensure the stability and reliability of the grid. To ensure coordination of electric system operations, the North American Electric Reliability Corporation developed and enforces mandatory grid reliability standards approved by the Federal Energy Regulatory Commission (FERC).

       電網的穩定來自於電力供給量能夠持續與需求量相應，要達成此一目標需要大量電網中運作不同功能部分的協作。美國電網包含了三大相連系統運作以保證穩定性以及可依賴性。為了確保穩定性以及可依賴性，北美電力可靠度公司(NERC)發展並實施聯邦能源管理委員會(FERC)核可強制性的電網可依賴性標準。

Electricity comes from various sources and types of providers

電力來自於不同來源以及類型的提供者

The origin of the electricity that consumers purchase varies. Some electric utilities generate all the electricity they sell using just the power plants they own. Other utilities purchase electricity directly from other utilities, power marketers, and independent power producers or from a wholesale market organized by a regional transmission reliability organization.

       消費者購買的電力有著於不同的來源。有些電力公司自己生產所銷售的電力，有些則會直接購買來自其他電力公司、電力經銷商、獨立發電廠或是區域

輸電組織(RTO)組成的批發市場的電力。

The retail structure of the electricity industry varies from region to region. The company selling you power may be a not-for-profit municipal electric utility; an electric cooperative owned by its members; a private, for-profit electric utility owned by stockholders (often called an investor-owned utility); or in some states, you may purchase electricity through a power marketer. A few federally-owned power authorities—including the Bonneville Power Administration and the Tennessee Valley Authority, among others—also generate, buy, sell, and distribute power. Local electric utilities operate the distribution system that connects consumers with the grid regardless of the source of the electricity.

       電力產業的零售結構會隨著區域而不同。零售電力的公司可能是非營利政府電力部門、會員組成的電力合作社、私人持股的公司，或是在某些州裡，個人可以透過電力經銷商購買電力。一些聯邦擁有的電力組織，包括邦尼維爾電力管理局、田納西河谷管理局等，也會生產、購買、銷售以及分配電力。無論電力來源為何，區域電力公司運作電力配送系統連接消費者以及電網。

The process of delivering electricity

電力運輸過程

The electricity power plants generate is delivered to customers over transmission and distribution power lines. High-voltage transmission lines, like those that hang between tall metal towers, carry electricity over long distances to where it is needed. Higher voltage electricity is more efficient and less expensive for long distance electricity transmission. Lower voltage electricity is safer for use in homes and businesses. Transformers at substations increase (step up) or reduce (step down) voltages to adjust to the different stages of the journey from the power plant on long distance transmission lines to distribution lines that carry electricity to homes and businesses.

　　電廠生產的電力透過電纜已及配電線輸送到消費者手上。連接高聳金屬塔的那些高壓電纜線攜帶電力至所要運送的遙遠某處，對於長程電力運輸而言，高壓電是更有效率以及成本較低的選擇。家用以及商用目的則以低電壓系統較為安全。電力從電廠出發，經由長途的輸送線到配電線，最後抵達民宅或商店的這段旅途中，變電站裡有著變壓器扮演著提高或降低電壓以符合各階段應用的角色。

Evolution of the electric power grid

電網的演變

At the beginning of the 20th century, more than 4,000 individual electric utilities operated in isolation from each other. As the demand for electricity grew, especially after World War II, utilities began to interconnect their transmission systems. These connections allowed utilities to share the economic benefits of building large and often jointly-owned electric generating units to serve their combined electricity demand at the lowest possible cost. Interconnection also reduced the amount of extra generating capacity that each utility had to hold to ensure reliable service during times of peak demand. Over time, three large interconnected systems evolved in the United States.

        二十世紀初，有超過四千個獨立運作的電力單位。隨著對電力的需求增加，特別是在二戰後，這些部門開始互相串連。單位間互相連結、建造共同持有的大型發電廠以較低的成本獲得電力來供給各自的需求，因而享有經濟利益。這種互聯也降低了各個部門所需準備用以應付尖峰用電時間的發電容量。隨著時間過去，美國出現了三個大型的互聯電力系統。

U.S. electrical systems are now interconnected

美國的電力系統已經互聯

Local electricity grids are interconnected to form larger networks for reliability and commercial purposes. At the highest level, the U.S. power system in the Lower 48 states is made up of three main interconnections, which operate largely independently from each other with limited transfers of electricity between them.

        出於有益於可依賴性以及商業的目地，區域電網透過互聯來形成更大的網絡。就最高的層級而言，美國電力系統中由三個主要的連結組成，除了彼此間一些受限的電力輸送，有很大的部分為獨立運作。

●The Eastern Interconnection encompasses the area east of the Rocky Mountains and a portion of the Texas panhandle.

●The Western Interconnection encompasses the area from the Rockies west.

●The Electric Reliability Council of Texas (ERCOT) covers most of Texas.

 　　東部連通電網(The Eastern Interconnection)觸及洛磯山脈以東以及部分德州西北部的區域。西部連通電網(The Western Interconnection)觸及洛磯山脈以西的區域。德州電力可靠協調會(ERCOT)則覆蓋了大部分德州。

The Eastern and Western Interconnections in the United States are also linked with the Canadian power grid. The network structure of the interconnections helps maintain the reliability of the grid by providing multiple routes for power to flow and by allowing generators to supply electricity to many load centers. This redundancy helps prevent transmission line or power plant failures from causing interruptions in service to retail customers.

        東部連通電網以及西部連通電網也與加拿大電網相連。互連的網絡結構透過提供多種電力傳輸路徑及允許發電端提供電力給多個用電端幫助維持了電網的可依賴性。這些重複性幫助避免了發生於傳輸電纜或者電廠的問題干擾零售用電端電力服務的使用。

Balancing authorities manage grid operations

平衡管制單位管理電網運作

These three interconnections describe the large-scale physical structure of the grid. The regional operation of the electric system is managed by entities called balancing authorities, whose primary job is to ensure that electricity supply constantly matches power demand. Most of the balancing authorities are electric utilities that have taken on the balancing responsibilities for a specific part of the power system. All of the regional transmission organizations in the United States also function as balancing authorities. ERCOT is unique in that the balancing authority, interconnection, and the regional transmission organization are all the same entity and physical system.

這三個互連單位構建了電網大尺度的物裡結構。區域電力系統的運作則由被稱為平衡管制單位的組織來管理，該組織首要的任務即為確保電力供給持續與需求相符。大部分的平衡管制單位為那些負有電力系統中特定區域平衡責任的電力公司，此外，多數的區域輸電組織(RTO)也有著平衡管制的功能。德州電力可靠協調會(ERCOT)特別在於其平衡管制單位、互連單位以及區域輸電組織都屬於同一個部門與物理系統。

A balancing authority ensures that electricity demand and supply are finely balanced to maintain the safe and reliable operation of the power system. If demand and supply fall out of balance, local or even widespread blackouts can result. Balancing authorities maintain appropriate operating conditions for the electric system by ensuring that a sufficient supply of electricity is available to serve expected demand, which includes managing transfers of electricity with other balancing authorities.

平衡管制單位必須確保電力供需的良好平衡以維持電力系統安全可依賴的運轉。如果供需失去平衡，則可能導致區域性或更廣闊區域的斷電事件發生。平衡管制單位透過確保對預期電力需求的足夠供給作為維持電力系統適當運轉所需的條件，這過程也包含管理與其他平衡管制單位之間的電力輸送。

Electric reliability organizations set standards for grid operations

電力可靠度組織為電網運作訂定標準

Electric utilities are responsible for maintaining the safety of their systems and planning for the future power needs of their customers. Initially, voluntary standards were developed by the electric power industry to ensure coordination of linked interconnection operations. Today, mandatory reliability standards for planning and operating power systems and for addressing security concerns at critical electrical infrastructure are in place. The North American Electric Reliability Corporation and its member organizations developed and enforces these standards, which FERC approved. In Canada, Canadian regulators fill this role.

        電力公司有責任維持電力系統安全以及規劃應對未來消費者對電力的需求。最初，電力公司自發性發展標準以確保互連電網間的協作；時到今日，用於規劃與運轉電力系統以及關注重要電力基礎建設安全性議題的強制性可依賴性標準以經到位。北美電力可靠度公司(NERC)及其子公司發展且實施了通過聯邦能源管理委員會(FERC)審核的標準；在加拿大，監管機構亦引入該標準。

Challenges facing the power grid

電網面臨著挑戰

Construction of electricity infrastructure in the United States began in the early 1900s and investment was driven by new transmission technologies, by central station generating plants, and by growing electricity demand, especially after World War II. Now, some of the older existing transmission and distribution lines have reached the end of their useful life and must be replaced or upgraded. New power lines are also needed to maintain the electrical system's overall reliability and to provide links to new renewable energy generation resources, such as wind and solar power, which are often located far from where electricity demand is concentrated.

　　在美國，電力基礎建設的建造始於二十世紀早期，新式的傳輸科技、中央發電廠、成長鍾的電力需求，特別是二戰後，也持續趨動著投資。今天，一些較老舊的書配電線已經來到使用年限的盡頭必須被更換或升級，需要新的電纜維持電力系統的可依賴性及連接新的可再生能源發電端，比如風力發電或太陽能發電，這些可再生能源發電端多位於遠離需求的地點。

Several challenges exist for improving the infrastructure of the grid:

●Siting new transmission lines (getting approval of new routes and obtaining rights to the necessary land)

●Determining an equitable approach for recovering the construction costs of a new transmission line built in one state when the line provides benefits to consumers in other states

●Addressing the uncertainty in federal regulations regarding who is responsible for paying for new transmission lines, which affects the private sector's ability to raise money to build transmission lines

●Expanding the network of long-distance transmission lines to renewable energy generation sites where high-quality wind and solar resources are located, which are often far from where electricity demand is concentrated

●Protecting the grid from physical and cyber attacks

        改善電網建設所面臨的一些挑戰：

        ●為新電纜選址(獲得新路線的核可與能夠通過必經之地的同意)

        ●當建設於某州的新電纜有益於其他州的消費者時，需提出公平的方案來攤

 平建設成本。

●處理關於誰有責任出資建設電纜的聯邦規範所帶來的不確定性，這些不確

 定通常會影響私部門集資建造的能力。

        ●拓展長程網絡到通常遠離電力需求處，卻有著高品質風力與太陽能的地點。

        ●保護電網不受物理性侵犯與網路攻擊。

The smart grid

智慧電網

The smart grid incorporates digital technology and advanced instrumentation into the traditional electrical system, which enables utilities and customers to receive information from and communicate with the grid. A smarter grid makes the electrical system more reliable and efficient by helping utilities reduce electricity losses and to detect and fix problems more quickly. The smart grid can help consumers intelligently manage energy use, especially at times when demand reaches significantly high levels or when a reduced energy demand is needed to support system reliability.

        智慧電網將數位科技及先進的儀器儀表應用於傳統的電力系統，使得電力公司以及消費者能夠從電網獲得資訊並與之溝通。智慧電網幫助電力公司減少電力損耗，也能夠快速修補問題，使得電力系統更可依賴也更有效率；另一方面，智慧電網也能夠幫助消費者更有智慧的管理能源使用，特別是尖峰用電時期或者需要減少電力使用以幫助系統穩定的時候。

Smart devices in homes, offices, and factories can inform consumers and their energy management systems of times when an appliance is using relatively higher-priced electricity. This helps consumers, or their intelligent systems, to optimally adjust settings that, when supported by demand reduction incentives or time-of use electricity rates, can lower their energy bills. Smart devices on transmission and distribution lines and at substations allow a utility to more efficiently manage voltage levels and more easily find out where an outage or other problem is on the system. Smart grids can sometimes even remotely correct problems in the electrical distribution system by digitally sending instructions to equipment that can adjust the conditions of the system.

        當某個設備使用了相對高價的電力時，裝設於家戶、商辦空間及工廠的智慧設備能夠通知消費者以及電力管理系統，這對於消費者或者智慧系統來說，配合著減少用電獎勵或依時用電費率，能夠最佳化的調整設定以降低電費。裝設於輸配電線以及變電站的智慧設備使得電力公司能夠更有效率的管理不同層級間的電壓值，也更容易找出造成停電或者其他問題的部位，並且可以透過發出指令遠端調整並修復配電系統中的問題。