电气工程及其自动化专业英语(二)(3)

（2）Use synchronous machines for generation of electricity. （2）使用电力同步一代机器。 Prime movers convert the primary energy (fossil, nuclear, and hydraulic) to mechanical energy that is, in turn, converted to electrical energy by synchronous generators. 牵引车转换的一次能源（化石，核能和水力）为机械能就是反过来，中，转换为电能的同步发电机。

（3）Transmit power over significant distances to consumers spread over a wide area. This requires a transmission system comprising subsystems operating at different voltage levels. （3）重大的距离发射功率超过的面积分布在一个广大消费者。这就要求传输系统的子系统组成的经营水平在不同的电压。

The basic elements of a modern power system in USA are shown in Fig.6-1. 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. 系统在美国一个现代化强国的基本要素是：1显示在图6 -。电功率）产生于发电厂（GS和传播给消费者通过一个复杂网络的各个组成部分，包括输电线路，变压器和开关设备。

It is common practice to classify the transmission network into the following subsystems: Transmission system; Subtransmission system; Distribution system. 它通常的做法是分类 传输网络分为以下子系统：传输系统; Subtransmission制度;分配制度。

Fig.6-1 图6 - 1

Basic elements of a power system 电力系统的基本要素1

The transmission system interconnects all major generating stations and main load centers in the system. 该传输系统互连所有主要发电厂在系统中心和主要负载。 It forms the backbone of the integrated power system and operates at the highest voltage levels (typically, 230 kV and above in USA). 它形成了系统的骨干力量的整合和经营水平在最高电压（通常为230千伏及以上美国）。 The generator voltages are usually in the range of 11 to 35 kV. 发电机的电压范围通常在11至35千伏。 These are stepped up to the transmission voltage level, and power is transmitted to transmission substations where the voltages are stepped down to the subtransmission level (typically, 69 to 138 kV). 这是加强宣传，电压等级输电和电力传输到传输）变电站的电压在那里下台的subtransmission水平（通常是69至138千伏。 The generation and transmission subsystems are often referred to as the bulk power system. 发电和传输子系统通常称为大容量电源系统。

The subtransmisson system transmits power in small quantities from the transmission substations to the distribution substations. 该系统传输subtransmisson变电站的电力由分布在小批量的输电站通过。 Large industrial customers are commonly supplied directly from the subtransmission system. In some systems, there is no clear demarcation between subtransmission and transmission circuits. 大工业用户通常

直接供应subtransmission制度。在一些系统中，没有明确划分输电线路之间subtransmission和。 As the system expands and higher voltage levels become necessary for transmission, the older transmission lines are often relegated to subtransmission function. 随着系统的扩展和更高电压等级输电成为必需的，旧的输电线路往往沦为subtransmission功能。

The distribution system represents the final stage in the transfer of power to the individual customers. The primary distribution voltage is typically between 4.0 kV and 34.5 kV. Small industrial customers are supplied by primary feeders at this voltage level. The secondary distribution feeders supply residential and commercial customers at 120/240 V. 分配制度代表了个人客户的最后阶段中的转移权力的。主要分布电压一般为4.0千伏和34.5千伏。小型电压等级的工业客户提供的主要是饲养在此。二次配电馈线供应住宅和五，商业用户在120/240

Small generating plants located near the load are also connected to the subtransmission or distribution system directly. Interconnections to neighboring power systems are usually formed at the transmission system level. The overall system thus consists of multiple generating sources and several layers of transmission networks. This provides a high degree of structural redundancy that enables the system to withstand unusual contingencies without service disruption to the customers. 小型发电厂附近的负载也连接到subtransmission直接或分配制度。系统互连到邻近的权力通常形成于水平的传输系统。整个系统网络由多个从而产生源的传播和若干层。这为一个客户高度结构性过剩，使系统中断承受无异常紧急服务。

三。翻译成中文以下

Instability may also be encountered without loss of synchronism. 不稳定性也可能会遇到不同步的损失。 For example, a system consisting of a synchronous generator feeding an induction motor load through a transmission line can become unstable because of the collapse of load voltage. 例如，一个系统包括一个同步发电机喂养通过传输线的感应电动机负荷的电压不稳定，因为可以成为负载的崩溃。 Maintenance of synchronism is not an issue in this instance; instead, the concern is stability and control of voltage. This form of instability can also occur in loads covering an extensive area supplied by a large system. 同步维修的问题不是一个实例在此，而是值得关注的是稳定和电压控制。这种不稳定的形式也可以在负载发生大面积覆盖的系统提供了一个大。 This kind of stability is referred to "voltage stability". 这种稳定性种被称为“电压稳定”。Rotor angle stability is the ability of interconnected synchronous machines of a power system to remain in synchronism. 转子角稳定系统的能力是一个相互关联的权力留在同步电机同步。 It 它 is most important to power system stability problems. 最重要的是电力系统的稳定性问题。 The stability problem involves the study of the electromechanical oscillations inherent in power system. 稳定问题涉及到电力系统的研究中固有的机电振荡。 A fundamental factor in this problem is the manner in which the power outputs of synchronous machines vary as their rotors oscillate. 阿在这个问题最根本的因素是何种方式的同步机的功率输出为不同的转子振荡。