無功規(guī)劃及其在功率管理中的運行畢業(yè)論文外文翻譯

1、<p><b>　　中文1970字</b></p><p>　　Reactive Power Planning</p><p>　　and Operating in the Deregulated Power Utilities</p><p>　　Ⅰ. INTRODUCTION</p><p>　　The p

2、urposes of this paper are to review the current strategy of reactive power management and search for proper reactive power strategy, which is expected to result in a more efficient and economic way in reactive power mana

3、gement. These goals are actually consistent with the spirit of the deregulation of power industry. Reactive power affects system voltages, energy loss as well as system security. As power system deregulation has been wid

4、ely accepted by power industry, the philosophy of react</p><p>　　Reactive power is always required during power delivery in an AC system even there are no reactive power loads. However, unlike real power, re

5、active power is not consumed by any elements of a power system. Reactive power is swapping twice per voltage cycle between capacitive elements and inductive elements. When capacitive elements are absorbing reactive power

6、, inductive elements must be releasing reactive power, and vise versa. The capacities of these capacitive/inductive elements are not alway</p><p>　　Reactive power compensation can be made at different levels

7、: distribution, transmission and generation. For a vertically integrated utility, the costs of reactive power compensation might be included into distribution cost or transmission cost depending on where the compensation

8、 devices are installed. The costs of reactive power supplied by generators might not be listed separately, or even the reactive power capacities of generators are not considered as the costs of reactive power. When utili

9、t</p><p>　　Under deregulation circumstance, power system security faces more threats than ever. Due to the potential dynamic power trading, the reactive power requirements are also dynamically changing. Some

10、 generation units are inefficient in generating real power and are not competitive on power market. However, they are necessary to stay online in order to maintain system voltage. This type of must-run units causes few a

11、rguments in the regulated power industry. Not all must-run units must be on-line all</p><p>　?、?REACTIVE POWER COMPENSATION ATDISTRIBUTION LEVEL</p><p>　　Main purposes of reactive power compensa

12、tion at load sites are to reduce long distance transmission of reactive power and reduce the reactive power flow within distribution network, thus reduce MW loss and voltage dip. Reactive power itself is sort of energy s

13、wapping between reactive element and capacitive element and is not consumed for pure reactive and capacitive elements. If most of reactive power load can be supplied at load sites, the amount of reactive power flow in ei

14、ther transmission ne</p><p>　　Fig. 1 is a 12-bus sample system which is a small piece of distribution network of New York City. The loads and shunt compensations shown in the figure are three phase total. Ba

15、lanced three-phase load is assumed in the calculation. Four compensation cases are presented to illustrate the effects on MW loss and voltage dip. All four cases are under same load conditions as shown in Fig. 1 except t

16、hat the reactive power compensations are different:</p><p>　　Case 1 : Without reactive power compensation.</p><p>　　Case 2: Reactive power compensations are shown in Fig. 1.</p><p>

17、　　Case 3: Total reactive power compensation of case 2(1380 KVAR) is made at Bus # 1</p><p>　　Case4: Reactive power compensation at Bus #1 is increased to obtain unity power factor.</p><p>　　Simi

18、lar situation can be found from bus voltages. Compensation method of case 2 is most effective in voltage improvement among those cases. Case 3 and case 4 have no direct effects on bus voltages of distribution network.<

19、;/p><p>　?、?REACTIVE POWER COMPENSATION IN TRANSMISSION NETWORK</p><p>　　For normal operation the compensation should be sufficient to keep the voltages of feeders within an acceptable range. For e

20、mergency operation the compensation should be able to keep the voltages within a wider acceptable range with the reactive power support from generation companies.</p><p>　　Fig. 2 is a small system of 110 bus

21、es, 136 branches including 71 transformers and 33 generators. System load is about 400 MW. Individual bus loads are not shown in the figure. The first case is base case. In the base case power factors of generators are n

22、ot necessary the same and, similarly, power factors of load buses are not necessary the same either. In the second case, load conditions are the same as base case, including 3 shunt compensations, but with the generators

23、 operating near unity pow</p><p>　?、?REACTIVE POWER RESREVE OF GENERATORS</p><p>　　The proposed reactive power management scheme assumes that generators are not responsible for reactive power su

24、pply under normal operation conditions. The generators, however, have to have sufficient reactive power reserve for contingencies. An important issue is how much reserve is necessary for each generator since reactive pow

25、er capacity directly affects generator price. Properties of contingency, location of power plant and criteria of voltage quality all affect the required amount of reacti</p><p>　　Ⅴ.CONCLUSIONS</p><

26、;p>　　This paper suggests that the distribution companies are responsible for the compensation of reactive power loads and the transmission companies are responsible for the necessary reactive power compensation to ens

27、ure the power delivery under normal conditions. The generation companies are responsible for reactive power requirements under contingency conditions. Transmission companies are entitled to charge to distribution compani

28、es for supplying reactive power load if the distribution companies a</p><p><b>　　英文文獻譯文</b></p><p>　　無功規(guī)劃及其在功率管理中的運行</p><p><b>　　Ⅰ、緒論</b></p><p>

29、;　　這篇論文的目的是評論無功管理的發(fā)展策略和尋找一個更適當?shù)臒o功策略，即期望其在無功管理中更有效更經(jīng)濟的方法。這些目標事實上是和電力工業(yè)異常時的精神是一致的。無功功率影響系統(tǒng)的電壓、能量損耗及系統(tǒng)安全。隨著電力系統(tǒng)違規(guī)規(guī)則被廣泛接受，為了會合規(guī)則的精神和安全需求，電力系統(tǒng)管理和電力系統(tǒng)運行方面的專家被寄予不同的期望。在一個垂直的、完整的效用體系中，無功設(shè)備通過相同的效用承認和運行。無功補償?shù)拇鷥r和貢獻并不是實際的估值。在違規(guī)條件下，無

30、功設(shè)備所有者的權(quán)利和職責成為本質(zhì)的事件，不僅影響電力工業(yè)的投資回報還影響電力系統(tǒng)的安全。這種情形在幾個自給的互相聯(lián)絡(luò)的系統(tǒng)中甚至更復雜。</p><p>　　無功功率在一個甚至沒有無功負載的交流系統(tǒng)的功率傳輸中也是必需的，不像有功，無功不被電力系統(tǒng)中的任何一個元件消耗。無功在容性元件和感性元件之間每一電壓周期交換兩次。當容性元件吸收無功，則感性元件必須發(fā)出無功，而且數(shù)值相同。這些容性/感性元件的容量并不常常是不變

31、的。線性負荷無功的量是均衡的，相關(guān)的連續(xù)電抗也是均衡的。</p><p>　　無功補償可以被調(diào)整在不同的標準：分配、傳輸、產(chǎn)生。作為一個垂直的完整的設(shè)備，無功補償器的成本或許包括在配電成本中或者在輸電成本中取決于補償設(shè)備的安裝位置。發(fā)電機無功補償?shù)墓┙o成本可能不被分離列出，或者甚至發(fā)電機的無功能量作為無功成本不被考慮。當設(shè)備作為無功規(guī)劃，不同的設(shè)備可能有不同的考慮。不管無功補償?shù)某杀驹鯓?，他們怎樣編制計劃，電費始

32、終反映這部分費用。在電力工業(yè)中，有幾個不嚴重的在控制時代被討論的問題被提出，像：誰負責無功功率的補償？是無功補償裝置提供，消費者是否需要支付無功負載的費用？發(fā)電機應(yīng)該在無功功率補償中擔當什么角色？等等。</p><p>　　在違規(guī)情況下，電力系統(tǒng)安全比以前面臨更多的威脅。由于電力潛在的動態(tài)交換，無功需求也是動態(tài)變化的。一些發(fā)電廠發(fā)出有功效率低下及在電力市場不具有競爭力。但是它們?yōu)榱思訌娤到y(tǒng)電壓保持上電網(wǎng)是必要的。

33、這種必須運行的電廠在被管制的電力工業(yè)引起一些爭議。依據(jù)負荷和運行條件，它們中的一些可以不用上網(wǎng)但是必須作為后備，另一些僅在確定的條件下必須上網(wǎng)。大部分發(fā)電機有實際最小視在功率輸出的限制，并且不能簡單地作為同步電容器運轉(zhuǎn)。它們的運行費用應(yīng)該包含視在功率成本。</p><p>　　II、配電網(wǎng)絡(luò)中的無功補償 </p><p>　　負載點無功補償?shù)闹饕康氖菧p小長距離輸電的無功功率和減少配電網(wǎng)絡(luò)

34、的無功潮流，以及減少功率損耗和電壓降落。無功功率自身是電抗性元件和電容性元件的能量轉(zhuǎn)化，及不被純電抗性元件和電容性元件所消耗。如果大部分無功功率負荷能被負載點提供，無功功率潮流的量不僅在輸電網(wǎng)絡(luò)而且在配電網(wǎng)絡(luò)中都可以減少。圖1是紐約城的配電網(wǎng)絡(luò)的一小部分關(guān)于12條母線的示例。圖中的負載和補償器都是三相的。對稱三相負載是在計算時被假設(shè)的。安裝4個補償器是為了舉例說明其在功率損耗和電壓降落中的影響。四個例子像圖1中所示是在相同的負載條件下除

35、非無功補償不同。</p><p><b>　　例1：沒有無功補償</b></p><p>　　例2：無功補償像圖1所示</p><p>　　例3：例2（1380 KVAR）在母線1所構(gòu)成的所有無功</p><p>　　例4：增加母線1 的無功以得到統(tǒng)一的功率因數(shù)</p><p>　　相似的條件可以

36、從母線電壓處找到。例2的補償方式在電壓改變中是所有例子中最有效的。例3和例4對配電網(wǎng)絡(luò)的母線電壓沒有直接的效應(yīng)。</p><p>　　III、輸電網(wǎng)絡(luò)中的無功補償</p><p>　　為了正常運行無功補償必須充足的以保持支流電壓在一個可接受的范圍內(nèi)。為了緊急運行無功補償必須能保持電壓在一個更寬的可接受的范圍從發(fā)電廠發(fā)出的無功。圖2 是110母線，136條支流包含71個變壓器和33個發(fā)電機系

37、統(tǒng)的小部分。初始母線負載沒有在圖中顯示。第一例是基礎(chǔ)的例子，在這個基礎(chǔ)的例子中發(fā)電機的功率因數(shù)不是必須相同，相似的負載母線的功率因數(shù)也不必要相同。在第二個例子中，負載條件和舉出例子是一樣的，包括3個補償器，但是發(fā)電機幾乎運行在統(tǒng)一的功率因數(shù)。第四個例子，發(fā)電機運行幾乎統(tǒng)一的功率因數(shù)而且所有的負載母線的功率因數(shù)分別為1.0，0.95，0.9，0.85。</p><p>　?、?、發(fā)電廠的無功儲備</p>

38、<p>　　被提議的無功管理策略假定在正常運行條件下發(fā)電機不負責無功的提供。但是發(fā)電機必須有充足的無功儲備。一個重要的問題是每個發(fā)電機應(yīng)該儲備多少的無功，因為無功的容量影響發(fā)電機的價格。偶然事故、電廠的地理位置、電能質(zhì)量的標準都影響發(fā)電機所需要的儲備無功的容量。在互相連接的系統(tǒng)中，連接的強度和鄰近的系統(tǒng)也有一定的作用。它不同于有功儲備的預(yù)算，電廠的儲運損耗必然沒有無功設(shè)備故障那么嚴格。所以發(fā)電廠為偶然事故的所準備的無功儲備應(yīng)