电气专业英语翻译!高手帮忙!Voltage stabilityVoltage stability is the ability of a power system to maintain steady acceptable voltages at all buses in the system under normal operating conditions and after being subjected to a disturbance.

电气专业英语翻译!高手帮忙!Voltage stabilityVoltage stability is the ability of a power system to maintain steady acceptable voltages at all buses in the system under normal operating conditions and after being subjected to a disturbance.
电气专业英语翻译!高手帮忙!Voltage stability
Voltage stability is the ability of a power system to maintain steady acceptable voltages at all buses in the system under normal operating conditions and after being subjected to a disturbance. A system enters a state of voltage instability when a disturbance, increase in load demand, or change in system condition causes a progressive and uncontrollable drop in voltage. The main factor causing instability is the inability of a power system to meet the demand for reactive power. The heart of the problem is usually the voltage drop that occurs when active power flow through inductive reactances associated with the transmission network.
Progressive drop in bus voltages can also be associated with rotor angles going out of step. For example, the gradual loss of synchronism of machines as rotor angles between two groups of machines approach or exceed 180° would result in very low voltages at intermediate points in the network. In contrast, the type of sustained fall of voltage that is related to voltage instability occurs where rotor angle stability is not an issue.
Voltage instability is essentially a local phenomenon; however, its consequences may have a widespread impact. Voltage collapse is more complex than simple voltage instability and is usually the result of a sequence of events accompanying voltage instability leading to a low-voltage profile in a significant part of the power system. Voltage instability may occur in different ways.
For purpose of analysis, voltage stability is usually classified into the following two subclasses:
(1) Large-disturbance voltage stability is concerned with a system’s ability to control voltages following large disturbances such as system faults, loss of generation, or circuit contingencies. This ability is determined by the system load characteristics and the interactions of both continuous and discrete controls and protections. A criterion for large-disturbance voltage stability is that, following a given disturbance and following system-control actions, voltages at all buses reach acceptable steady-state levels.
(2) Small-disturbance voltage stability is concerned with a system’s ability to control voltages following small perturbations such as incremental changes in system load. This form of stability is determined by the characteristics of load, continuous controls, and discrete controls at a given instant of time. A criterion for small-disturbance voltage stability is that, at a given operating condition for every bus in the system, the bus voltage magnitude increases as the reactive power injection at the same bus is increased. A system is voltage-unstable if, for at least one bus in the system, the bus voltage magnitude decreases as the reactive power injection at the same bus is increased.

电气专业英语翻译!高手帮忙!Voltage stabilityVoltage stability is the ability of a power system to maintain steady acceptable voltages at all buses in the system under normal operating conditions and after being subjected to a disturbance.
电压稳定性是指电力系统在正常的运行条件下或者在受到扰动时所有的节点都能维持可接受的稳定电压的能力.当系统因扰动、负荷增大或系统条件变化而导致电压失控而逐渐降低时,系统将进入电压不稳定状态.导致不稳定的主要因素是当电力系统无法满足对无功功率的需求的情况.这个问题的核心是电压降低通常发生在当有功功率流过感性阻抗连接的输电网络中.
电压的逐渐降低同样会体现在转角的失步.例如,两组机器逐渐失去同步,转角接近或超过180°将会导致电网的连接点的低电压.相反,与电压不稳定相关的电压持续下降发生在转角稳定性不是问题的条件下.
电压稳定性本来属于系统自身的现象,然而,它可能带来扩散性的后果.电压崩溃比单纯的电压不稳定更加复杂.电压崩溃通常是由一系列的电压不稳定事件所导致的,并会使得着电力系统某些重要部分的电压大幅度降低.电压不稳定的产生有不同的方式,为了分析方便,电压不稳定通常划分为以下两个子类：
（1）大扰动下的电压稳定性是指一个系统在受到大的扰动,譬如系统故障,发电机退出运行或线路意外事故等情况时系统控制电压的能力.这个能力是由系统的负荷属性和连续及离散的控制和保护的交互作用决定的.一个衡量大扰动下电压稳定性的标准就是在给定的扰动下经过系统控制,各个节点的电压肯以维持在可以接受的稳定水平.
（2）小扰动下的电压稳定性是指系统在受到小的扰动时,譬如系统负荷的小幅增加,系统控制电压的能力.这种能力是由负荷特性,连续控制和某指定时刻的离散控制来决定的.一个衡量小扰动下电压稳定性的标准是不论系统的哪一个节点,当给该节点注入无功功率时,其电压幅值会随之升高.若系统中至少有一个节点在注入无功功率时电压下降,则该系统为电压不稳定系统.