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1.
Reliability of power distribution schemes can always be improved at the expense of cost and size. The addition of extra paths proves to increase the continuity of supply but it adds more complexity to the system and the system structure may become very complex. In complex distribution system, there are several difficulties in reliability evaluation: reliability, availability and MTBF. Subsystems may follow various failure distributions; subsystems may conform to arbitrary failure and repair distributions for maintained systems; the failure data of subsystems are sometimes not sufficient and reliability test sample sizes tend to be small. Hence, simplification for the reliability inputs, electrical parameters and load data are needed.In this paper, a simple reliability-oriented method to calculate some complex distribution system reliability such as ring and triple-bus systems is presented. The major purpose is to simplify the reliability inputs, electrical parameters and load data. The simplification assumes that the repair time here is a random variable, and certain values of repair times are usually so small that can be neglected at each load point. Therefore complete reliability analysis with repair time omission and modified availability (reliability) and unavailability (h/year) can be obtained at each load feeder point using the simple methods of probability and the theory of sets. This approach is dealt with in this paper and a general formula for calculation of n-feeder ring-bus reliability is developed and applied to some practical distribution schemes.In an n-feeder ring-bus system, it is found that the reliability of each feeder is decreased by increasing the number of the outgoing feeders, so it is recommended that the total number of the outgoing feeders in this scheme should be carefully decided.A meshed network (triple-bus scheme), which makes it possible to serve the consumers from three sources is also considered. With this scheme, the reliability of the outgoing feeders is largely improved as compared with the ring-bus system.  相似文献   
2.
This paper presents a novel model for optimal coordinated voltage emergency control (OCVEC). It takes account of the dynamics of loads and discrete/continuous nature of controls with coordination of dissimilar controls at different geographical locations in order to keep the desired voltage profiles against voltage collapse during an emergency. An integration index of the bus voltage deviation is adopted as the voltage stability performance index. The sensitivities of this performance index with respect to controls are derived using the optimal control theory. Since the sensitivities can be evaluated using the fast quasi-steady-state time domain simulation results, the intractable OCVEC model can be transformed into a tractable problem of quadratic programming. The effectiveness of the proposed model and its solution strategy is validated by case studies on the New England 39-bus and Nordic 32 power systems.  相似文献   
3.
This paper provides a probabilistic method to assess the impact of wind turbines (WTs) integration into distribution networks within a market environment. Combined Monte Carlo simulation (MCS) technique and market-based optimal power flow (OPF) are used to maximize the social welfare by integrating demand side management (DSM) scheme considering different combinations of wind generation and load demand over a year. MCS is used to model the uncertainties related to the stochastic variations of wind power generation and load demand. The market-based OPF is solved by using step-controlled primal dual interior point method considering network constraints. The method is conceived for distribution network operators (DNOs) in order to evaluate the effect of WTs integration into the network. The effectiveness of the proposed method is demonstrated with an 84-bus 11.4 kV radial distribution system.  相似文献   
4.
Multistage distribution network expansion because of load growth is a complex problem in distribution planning. The problem includes minimizing cost of objective function subject to technical constraints. The objective function consists of investment, operation and reliability costs. In this paper, HV/MV substations, main and reserve MV feeders, dispatchable DG sources and storage units are considered as possible solutions for multistage distribution expansion planning. A three-load level is used for variable load and some strategies are proposed for DG and storage units operation. A modified PSO algorithm is applied to solve the complex optimization problem. Numerical results of the case studies show the ability of the modification. Moreover, the proposed strategies improve the distribution network from both economical and reliability points of view compared with the other methods.  相似文献   
5.
设计了一种针对多媒体彩铃项目Portal系统的统一开发框架,并举例说明该框架在多媒体彩铃业务中的应用.UP(Unify Portal)框架基于传统的Spring+Hibernate开发框架,延续并优化了分层的体系结构;使用了面向接口编程和AOP(Aspect Oriented Programming,面向切面编程)的设...  相似文献   
6.
高成熟度的CMMI模型强调过程稳定与量化管理和统计管理的思想在项目中的应用,而量化管理的根本是建立完善的度量体系.重在介绍支撑量化管理的方法和工具,从过程执行力、质量、工作量偏差这几项目标分别介绍量化判断的方法.本企业通过这些方法和工具的使用,在项目管理过程中得到准确的统计数据,不断提高量化管理的水平,从而帮助企业不断...  相似文献   
7.
本文分析了污水提升泵站格栅除污机及螺旋输送机自动控制运行原理,以西门子S7-300系列PLC为例,设计出了PLC控制程序.  相似文献   
8.
随着互联网技术的不断发展,其相关技术也在逐渐完善,其中物联网作为新兴的事物开始走入人们的视线.物联网的核心就是通过物与物之间的交互来完成工作的自动化.目前,我国医药流通过程复杂,尤其经过了繁多的流通过程,大大的增加了药品的价格,且流通效率低.本文的研究内容主要针对物联网技术在医药流通领域的应用.  相似文献   
9.
针对某炼钢车间除尘控制系统改造过程中的实际需要,借助于IM- 308C模板,实现了 S7与S5 PLC之间的数据交换,成功解决了HMI 画面与S7 300 PLC间的通讯问题.  相似文献   
10.
针对卟啉传感阵列(PSA)图像中卟啉点阵列可能发生倾斜的现象,设计了一种自动校正算法.算法之初对图像进行滤波、对比度增强操作,并求得图像的二值形态学边界,利用此二值边界图像作为求取倾斜角度运算的输入,减少了噪声的影响,同时也降低了时间的花费;而后利用radon变换与功率谱结合的方法来求取倾斜角度,解决了单纯的radon...  相似文献   
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