220KV变电站外文翻译

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1、山东理工大学毕业设计外文翻译材料）学院：电气与电子工程学院 专业：电气工程及其自动化 学生姓名：指导教师：State enumeration technique combined with a labelingbusset approach for reliability evaluation ofsubstationconfiguration in power systems1. IntroductionSubstation reliability can be assessed using either Monte Carlo simulation or analytical method

2、s 17. There are two popular enumeration techniques for reliability evaluation of substation configuration in power systems: cut set enumeration 69 and network state enumeration 1,2. There exist two essential differences between the two techniques. The first one is that in the cut set method, the min

3、imum cut sets that lead to a network failure have to be identified before all of them are enumerated, whereas in the network state technique, network states are enumerated first and then an appropriate approach is used to identify whether each of the states is a failure one or not. The second one is

4、 that a cut set contains only failed components whereas a network state is defined by both failed and non-failed components.The network state technique has following features compared to the minimum cut set method: Dependent failures between components can be easier to incorporate, such as one compo

5、nent failure causing outages of multiple components, cascading failures, etc. 1,2. Multiple failure modes of network components can be easier to consider, such as active and passive failures of a component in a substation configuration 1,2. Operation actions can be taken into consideration. This req

6、uires a model for multiple states of components, such as success, repair and switching states for a component in a substation configuration 1,2. Network states could be mutually exclusive if the enumeration is properly performed. The first three features are due to the fact that the network state te

7、chnique focuses on a state of whole network that can easily cover any status of substation components including operational switching and cascading failure sequences. The fourth merit can result in significant simplification in calculations compared to the minimum cut set method. The total failure p

8、robability is simply a sum of probabilities of mutually exclusive network failure states in the network state technique. Identifying2. ExampleThe example is a simple substation network as shown in Fig. 4. The network includes three breakers and two transformers.Losing load at the bus load is used as

9、 the criterion of substation network failure.2.1. Considering only open circuit failuresIn order to compare the network state technique with the minimum cut set method, it has been first assumed that only open circuit failures of transformers and breakers are considered and all short circuit faults

10、are ignored. To obtain a relatively simple analytical expression of the result, it is assumed that the open circuit failure probability of all the breakers and transformers is identical and it is U. In the computer program, different failure probability values for different components can be easily

11、specified in the data file. Using the cut set method, four minimum cut sets are identified.They are: S1 = (T1, T2; S2 = (B1, B2), S3 = (B1, B3, T2);S4 = B2, B3, T1). The probability of substation network failure is calculated by Fig. 4. A simple substation network.Pf = P(S1US2US3US4)=2U2+ 2U3 5U4+ 2

12、U5(4)As usual, the four minimum cut sets are not mutually exclusive. The calculations from the left side of the second equality sign to its right side are associated with intersections among the minimum cut sets. For this simple case, it can be expressed asfollows:Pf =P(S1 U S2 U S3 U S4)=P(S1) + P(

13、S2) + P(S3) + P(S4) P(S1 n S2)p(si n S3) P(S1 n S4) p(s2 n S3) p(s2 n S4)-p(s3 n S4)+ p(si n S2 n S3)+ p(si n S2 n S4)+p(si n S3 n S4)+ p(s2 n S3 n S4) -P(S1 n S2 n S3 n S4) (5)For a relatively large network, identifying all minimum cut sets and performing calculations of the union of non-mutually e

14、xclusive cut sets require considerable computational efforts. Using the presented network state enumeration with the labeling bus set approach, 16 network states are identified as failure states that lead to loss of load. Generally, although the number of network failure states is more than the numb

15、er of minimum cut sets, it is much easier and faster to identify them using the labeling bus set approach in programming. Particularly, once the network failure states are identified, the total network failure probability is just the sum of probabilities of all network failure states without any cal

16、culation associated with the union and intersections. In this example, we can have the following analytical expression of substation network failure probability:Pf = 2U2(1 - U)3 + 8U3(1 - U)2 + 5U4(1 - U) + U5 (6)It is interesting to note that Eqs. (4) and (6) look so different but they lead to the

17、same result. This can be proven by assign Ua value. For instance, by letting U= 0.015, the substation network failure probability from both the equations is identical, which is 0.000456498.2.2. Considering both open circuit failures and short circuit faultsIt is relatively difficult for the cut set

18、method to incorporate dependent failure events, multiple failure modes and switching actions, which are associated with short circuit faults and need to be modeled in reliability evaluation of a substation configuration.It has been assumed in this example that the breakers can clear their own short

19、circuit faults and only the short circuit faults on the two transformers are considered. When a short circuit fault happens on either transformer, the breakers B1 and B2 will be opened by a protection action. This results in a switching state. In this state, B1 and B2 are still healthy components. T

20、heir outages are not due to a failure and cannot be treated as components in a cut set. Then, the switches (not shown in the figure) at both sides of the failed transformer are manually opened to isolate it, and B1 and B2 are re-closed so that the load may be supplied through another transformer if

21、the second transformer is not simultaneously down. This second state corresponds to a repairing state of the faulted transformer.3. ConclusionsThe network state enumeration technique combined with the labeling bus set approach proposed in the paper is suitable for reliability evaluation of a substat

22、ion configuration or a looped distribution network that needs to model dependent failures, multiple failure modes and multiple states of components.Another advantage of the presented network state enumeration technique is that enumerated network states are mutually exclusive resulting in great simpl

23、ification in calculating the total network failure probability compared to the minimum cut set method. The key in the presented technique is identification of whether a state is a failure one or not. The labeling bus set approach has been proposed for this purpose.A substation configuration is used

24、to explain the procedure including a switching action associated with dependent outages and multiple states of network components. The presented method is easy to program and can be applied to any substation or looped distribution networks.The example of a substation network demonstrates that in the

25、 case of considering only open circuit failures, the same result is obtained using the proposed method and the minimum cut set method. The example also shows that the presented technique can handle the case of considering both open failures and short circuit faults which are associated with switchin

26、g actions and protection logic.结合国家统计技术在电力系统的配置标签母线变电站集方法的可靠性评价1 介绍 变电站的可靠性可以使用蒙特卡洛仿真法或者分析法进行评估 1-7。变 电站电力系统配置的可靠性评估有两种流行的列举方法：割集枚举 6-9 和网 络状态枚举 1，2。这两种方法存在两个本质区别。第一，在割集枚举中， 引起网络故障的最小割集数必须在进行枚举前确定，然而在网络状态枚举中 首先进行网络状态枚举，然后才用恰当的方式来判定状态是否故障。第二， 割集枚举只包含故障部分，而网络状态枚举包括故障部分和正常部分。网络状态枚举具有以下特点：*可以轻松包容组件之间的依赖

27、性故障，例如一个部件引起的多部件断 电，串联故障，等等 1，2。*可以轻松考虑到网络组件的多故障模型，例如在变电所结构中组件的 积极，消极故障 1，2.*可预料的操作行动。这需要一个多状态组件的模型，例如变电所结构 中组件的成功，修理和转换状态 1，2.*如果枚举正常进行，网络状态可能会相互排斥。前三个特点是由于网络状态枚举法重点关注可以轻松涉及包含操作转 换和串联故障在内的任何变电所结构状态的整个网络。第四个特点是由于相对于最小化割集枚举更简化的运 算造成的，总故障概率是网络状态枚举中相互排斥网络故障率的总和。变电站的可靠性可以使用蒙特卡洛仿真法或者分析法进行评估 1-7。变 电站电力系统配

28、置的可靠性评估有两种流行的列举方法：割集枚举 6-9 和网 络状态枚举 1，2。这两种方法存在两个本质区别。第一，在割集枚举中， 引起网络故障的最小割集数必须在进行枚举前确定，然而在网络状态枚举中 首先进行网络状态枚举，然后才用恰当的方式来判定状态是否故障。第二， 割集枚举只包含故障部分，而网络状态枚举包括故障部分和正常部分。网络状态枚举具有以下特点：*可以轻松包容组件之间的依赖性故障，例如一个部件引起的多部件断电，串联故障，等等 1，2。*可以轻松考虑到网络组件的多故障模型，例如在变电所结构中组件的 积极，消极故障 1，2.*可预料的操作行动。这需要一个多状态组件的模型，例如变电所结构 中组

29、件的成功，修理和转换状态 1，2.*如果枚举正常进行，网络状态可能会相互排斥。 前三个特点是由于网络状态枚举法重点关注可以轻松涉及包含操作转 换和串联故障在内的任何变电所结构状态的整个网络。第四个特点是由于相对于最小化割集枚举更简化的运 算造成的，总故障概率是网络状态枚举中相互排斥网络故障率的总和。2例子图 4 是一个普通变电所网络。网络包括三个断路器和两个变压器。总线 负载的损失负载作为变电所网络故障标准。2-1 只考虑开路故障 为了比较最小割集枚举方法和网络状态枚举方法，首先假设只考虑变压 器和断路器的开路故障，忽视所有短路故障。为了简化结果表达式，假设变 压器和断路器的所有失效概率都为U

30、。在计算机程序中，不同组件的失效概 率可以在数据文件中轻易找到。使用割集枚举，确定四个最小割集数：S1 = (Tl, T2; S2 = (Bl, B2), S3 = (B1, B3, T2);S4 = B2, B3, Tl).变电站网络故障概率公式：Pf = P(S1 U S2 U S3 U S4) = 2U2 + 2U3 ? 5U4 + 2U5 (4)图四，简单变电站网络。 像往常一样，四个最小割集数不互相排斥。第二个等式的左右两边表明与最小割集数取交集。对于这种情况，原等 式可以表达为：Pf = P(Sl U S2 U S3 U S4)=P(S1) + P(S2) + P(S3) + P(

31、S4) -P(S1 n S2)-p(si n S3) - P(S1 n S4) - P(S2 n S3) - P(S2 n S4)-p(S3 n S4)+ p(si n S2 n S3)+ p(si n S2 n S4)+p(si n S3 n S4)+ p(S2 n S3 n S4)-p(S1 n S2 n S3 n S4) (5)对于一个相对大型网络，确定所有最小割集数并且计算不发生出相互排 斥的割集需要相当大的计算量。利用网络状态枚举和标记总线设置方法。16 个网络状态故障会导致丢失负载。通常，尽管网络状态枚举数要比最小割集 数多，但使用标记总线程序它可以更方便快捷的确定它们。特别是在网

32、络状 态故障已经确定时，不用计算相关的交集与合集，总失效概率就是所有网络 状态故障率总和。在这个例子中，我们可以得到以下关于变电站网络故障率 的表达式：pf = 2U2(1 ? U)3 + 8U3(1 ? U)2 + 5U4(1 ? U) + U5 (6)等式4与等式6看上去不同，但他们的结果相同。这可以通过给Va负 值验证。例如，设 U=0.015.变电站的故障率可以通过两个等式获得， 0.000456498.2.2 同时考虑开路和短路故障对于割集枚举法来说，与短路故障结合的合并从属故障，多重故障模式 和转换行为非常困难，需要变电站构造可靠性评估的模式化。假设在例子中 断路器可以忽视自己电路

33、中的短路故障，所以只考虑两个变压器中的短路故 障。当任意一个变压器发生短路。断路器B1,B2会出于保护目的开启。这就 导致了转换状态。在这种状态下，B1,B2还都是正常组件。它们断电是由于 一个故障，所以不能按照一个割集原件处理。然后，故障变压器两端的断路 器手动打开用来隔绝它，B1,B2重新关闭，所以，假如另一个变压器没有坏， 可以依靠正常变压器提供负载。这第二种状态相当于修复故障变压器状态。在网络技术应用领域，无论是有关所举例子的具体描述还是大体的演算 都是相当直接和简单的，这将在第二部分简单的描述。关键是要确定一个网 络状态的列举是否是一个失败的或不存在的例子。这需要确定相互间的电源 母

34、线和每个负载母线的连接情况。对母线连接情况的说明是为了提出并解释 第三部分中使用的变电站配置。第四部分是举例。3总结这篇文章中，将网络技术举例和母线连接情况相结合的办法的提出是为 了评估变电所配置的可靠性或者利用模型、多种故障模式和组件的多个情况 来说明一个环网分布网络。另一个方法是利用网络状态列举技术是列举网络 状态的相互排斥使计算极大的简化，造成与最小割集方法相比，整个网络失 败的可能性增加。关键是要确定一个网络状态的列举是否是一个失败的或不 存在的例子。对母线情况的说明也表明了这一目的。变电站配置是一个程序 的整体，包括一个简单的开关的切换动作都是网络部分多种状况和多重中断 的联合反映。该方法易于编程，可以适用于任何变电站或环状分布网络。该 网络的一个变电站的例子表明，在只考虑开路故障时，使用该方法和最小割 集的方法得到相同的结果。这个例子也表明，该技术可以处理同时考虑空载 和短路情况下，开关动作和程序保护设置的一致性。外文翻译（译文）