电力专业英语翻译(第二版).doc

A decrease in the field current gives rise to lagging (inductive) current in the stator; and increase in the field current that overexcites the motor causes a leading (capacitive) current to appear in the stator. 励磁电流减小时，定子电流感性增强；励磁电流增加使电机过励时将在定子中产生容性电流。 An induction machine is an AC two-winding unit in which only one (primary, usually the stator) winding is supplied with an alternating current at a constant frequency 1 from an external source. 感应电机是一种具有双绕组的交流电气设备，它只有一个绕组（一次侧，通常是定子）通过外电源输入固定频率为1的交变电流。 Current transformers for protection are essentially similar to those used for the operation of ammeters, watthourmeters and other instruments. 保护用电流互感器基本上同操作用的电流表、电能表和其他仪器类似。 DG planning also involves arranging for connection of the renewable power generator with the local grid, and for support of any local electric load when the renewable source is not available. 分布式发电规划还包括安排可再生能源发电机与地方电网相连接，这样当可再生能源不可用时，本地电力负荷仍能得到支持。 Distributed generation can include renewable power generation resources such as wind, solar, or low-head hydropower production. 分布式发电可以包括可再生发电资源，例如风能、太阳能或低水头水力发电。 Distributed generation, or DG, includes the application of small generators, typically ranging in capacity from 15 kW to 10000 kW, scattered throughout a power system, to provide the electric power needed by electrical consumers. 分布式发电包括小型发电机组的应用，容量通常从15kW到10000kW不等，这些机组散布在整个电力系统中，为用户提供所需的电能。 Each single thyristor valve consists of a certain amount of series connected thyristors with their auxiliary circuits. 晶闸管阀由一定数量的串联晶闸管及其附属电路组成。 Each single valve in the converter bridge is built up with a certain number of series-connected IGBTs together with their auxiliary electronics. 换流器桥阀由一定数量的串联IGBT（绝缘栅门极晶体管）及其附属电路构成。 Electric power is produced at generating stations (GS) and transmitted to consumers through a complex network of individual components, including transmission lines, transformers, and switching devices. 电能由发电厂发出，然后通过由诸如输电线路、变压器、开关设备这些独立部件组成的复杂网络输送到用户。 However, the single serious problem encountered with EHV voltage levels is the overvoltages during switching operations, commonly called switching-surge overvoltages. 然而，超高压电压等级面临的一个严重问题是进行开关操作时产生的过电压，通常称为操作冲击过电压。 In the conversion process the converter consumes reactive power which is compensated in part by the filter banks and the rest by capacitor banks. 换流器转换时需要消耗无功，消耗的无功一部分由滤波器组补偿，另一部分由电容器组补偿。 Induction machines are also called “asynchronous” because their operating speed is slightly less than synchronous in the motor mode and slightly higher than synchronous in the generator mode. 感应电机也称“异步电机”，这是因为其作为电动机时，（转子）工作速度略小于同步速，作为发电机时，略高于同步速。 More often than not induction machines have a three-phase, symmetrical (balanced), heteropolar winding on the stator and a three (or poly-) phase, symmetrical heteropolar winding on the rotor. 感应电机的定子和转子上通常具有三相对称异极性的绕组。 Most types of distributed generators utilize traditional power generation paradigms diesel, combustion turbine, combined cycle turbine, low-head hydro, or other rotating machinery. 大多数类型的分布式发电机都利用像柴油机（狄赛尔机)、燃气轮机、联合循环汽轮机、低水头水力发电或者其他旋转机械这样的传统发电模式。 Prime movers convert the primary sources of energy (fossil, nuclear, and hydraulic) to mechanical energy that is, in turn, converted to electrical energy by synchronous generators. 原动机将一次能源（化石能源、核能、水能）转换为机械能，然后，再由同步发电机转变为电能。 The coordination of insulation must now be based on switching impulse levels (SIL) and not on lightning impulse levels only. 现在，绝缘配合不仅仅要取决于雷电冲击等级了，还必须考虑到操作冲击等级。 The fundamental progress that occurs in a HVDC system is the conversion of electrical current from AC to DC (rectifier) at the transmitting end, and from DC to AC (inverter) at the receiving end. 高压直流输电的基本过程是，在线路的送端，交流转换成直流（整流），在线路的受端，直流转换成交流（逆变）。 The main advantage of a synchronous motor is that it can operate on a leading current, i.e. it can act as a capacitive load for the power line. 同步电机的主要优点是它可以发出感性电流，即它可以作为电力线的容性负载。 The synchronous capacitor is a synchronous machine running without load and designed to improve the power factor of the AC system. 同步电容器是一种空载电气设备，其作用是提高交流系统的功率因数。 The use of series capacitors to increase power-handling capacity has brought its own problems such as increased current density, temperature rise of conductors, increased short-circuit current and subsynchronous resonance. 使用串联电容器提高功率处理容量的方法也存在问题，如导致电流密度增加，导体温度上升，短路电流变大，次同步谐振增大。 This measurement would be dangerous and expensive, and indeed impossible, to achieve if the actual load and fault currents, often very large, and at a very high v