電力系統(tǒng)中英文外文文獻(xiàn)翻譯-資料下載頁(yè)
2024-12-05 20:54本頁(yè)面
【導(dǎo)讀】傳輸、分配系統(tǒng)相關(guān)的經(jīng)濟(jì)、工程問題也隨之增多。這些系統(tǒng)構(gòu)成了一個(gè)完整的。生成電的能源以煤、石油，或水庫(kù)和湖泊中水的形式儲(chǔ)存起來，以。但這并不會(huì)降低用戶對(duì)發(fā)電機(jī)容量的需求。顯然，對(duì)電力系統(tǒng)而言服務(wù)的連續(xù)性至關(guān)重要。沒有哪種服務(wù)能完全避免可。能出現(xiàn)的失誤，而系統(tǒng)的成本明顯依賴于其穩(wěn)定性。戶要求等的綜合體現(xiàn)。然而，網(wǎng)絡(luò)可靠性的增加是通過應(yīng)用一定數(shù)量的生成單元。相對(duì)于其他交流系統(tǒng)而言，耗的情況下，三相系統(tǒng)所需銅或鋁僅為單相系統(tǒng)的75%。在大型蒸汽發(fā)電站中，蒸汽中的熱能通過渦輪輪轉(zhuǎn)換為功。裝在軸承上并封閉于汽缸中的軸或轉(zhuǎn)子。動(dòng)而平衡地轉(zhuǎn)動(dòng)。開渦輪后會(huì)通過一冷凝器。果，從而提高蒸汽的膨脹率、后繼效率及渦輪的輸出功率。蒸汽進(jìn)入渦輪時(shí)壓力較高、體積較小，而離開時(shí)。立的柴油發(fā)電機(jī)，以備緊急情況時(shí)使用。情況以確保系統(tǒng)處于最佳工作狀態(tài)。的其余設(shè)備仍繼續(xù)工作。
【正文】 y to avoid damage due to overload. As load increases from month to month, 6 points at which additional capacity of equipment is required may be recognized and provision made for the installation of additional equipment. Thus instrumentation serves as a guide for future construction in a growing power system. Occasionally, under emergency conditions, a system operator observes that his system load exceeds the ability of the available generating and transmission equipment. He is then faced with the problem of load shedding or ,more properly, load conservation. It is then necessary to drop selected loads where service interruption is least objectionable. In such an event, he relies on the many instruments which provide information relative to systemoperation conditions. Instruments may sound alarms as advance warnings of conditions requiring action to avoid damage to equipment operating beyond its design limitation. In the event of extreme conditions such as powersystem faults, defective equipment is switched out of service automatically. Instruments that continuously monitor current voltage, and other quantities must be able to identify the faulted equipment and to bring about operation of the circuit breakers which remove it from service, while leaving in service all other equipment on the operating system. The many different electrical devices on a power system and those owned by the customers are designed for operation within certain specified ranges. Operation, excessive deterioration, or (in extreme cases ) the destruction of the device. Careful attention to the conditions under which equipment is operating may indicate corrective action that must be taken. Overcurrent on all electrical devices is undesirable, as it produces excessive temperatures, inefficient operation, and reduced service life. Overcurrent in residential circuits may bring about disconnection of the circuit by fuse or breaker action. Overcurrent in motors may damage insulation, with possible early insulation failure. Undervoltage considerably reduces the efficiency of incandescent lamps and may result in nonoperation of fluorescent lamps. Undervoltage of the power supply to motors may result in excessive currents in the motors, with possible damage to windings. Overvoltage increases the light output of lamps but in many instances seriously shortens useful life. Overvoltage applied to motors and transformers may result in excessive losses within the iron, with possible damage to the iron or to the adjacent winding insulation. Overspeed of rotating machines may result in structural damage to rotating parts. The overspeed of the customers’ production equipment may result in an inferior quality of the product. An outofstep condition existing between two generators or between a generator and a synchronous motor results in an interruption of useful power transfer between the two machines. An outofstep condition should be recognized promptly and the machines separated from each other. They may then be resynchronized and brought back into service. Instruments of many different types must be installed at many locations on a power system and on the premises of the many customers. With such instruments, conditions existing on the system may be continuously monitored.
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