体制转型与企业文化建设的战略思考

企业文化是企业核心竞争力之所在，处于体制转型过程中的国有企业，一方面要建立合乎市场经济要求的现代企业制度，另一方面要实现企业文化的延续与创新。论述了要在全面把握改革前和改革过渡时期国企的企业文化特征的基础上，正确处理企业文化建设的几个基本关系。     

基于白鲸优化算法的配电网故障恢复方法

提出了一种基于白鲸优化（BWO）算法的配电网故障恢复方法。首先,建立光储、风储系统模型以及负荷模型,以故障后重要负荷损失量最小为目标函数,进行配电网的初步孤岛划分。其次,以网络损耗和开关操作次数加权求和最小为目标,采用BWO算法求解,获取孤岛划分与开关操作配合的故障恢复结果。然后,通过3种场景对比,验证了所提方法能够在不同故障时段获得配电网故障恢复的最优结果。最后,将BWO算法与二进制粒子群优化算法、灰狼优化算法的运行结果进行对比,验证了BWO算法寻优效果更好。     

Evaluating expectations about negative emotional states of aggressive boys using Bayesian model selection.

Researchers often have expectations about the research outcomes in regard to inequality constraints between, e.g., group means. Consider the example of researchers who investigated the effects of inducing a negative emotional state in aggressive boys. It was expected that highly aggressive boys would, on average, score higher on aggressive responses toward other peers than moderately aggressive boys, who would in turn score higher than nonaggressive boys. In most cases, null hypothesis testing is used to evaluate such hypotheses. We show, however, that hypotheses formulated using inequality constraints between the group means are generally not evaluated properly. The wrong hypotheses are tested, i.e.. the null hypothesis that group means are equal. In this article, we propose an innovative solution to these above-mentioned issues using Bayesian model selection, which we illustrate using a case study. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

基于ARM的主动频率偏移孤岛检测法的实现

阐述了一种基于ARM的主动频率偏移检测孤岛效应的方法。通过计算,验证了SPWM对频率偏移精度调整的可行性。利用正反两次调整频率偏移量,达到快速,准确并且对电网不产生任何干扰的情况下检测出孤岛效应。     

Hybrid intelligent water drop bundled wavelet neural network to solve the islanding detection by inverter-based DG

In this paper, a passive neuro-wavelet based islanding detection technique for grid-connected inverter-based distributed generation was developed. The weight parameters of the neural network were optimized by intelligent water drop (IWD) to improve the capability of the proposed technique in the proposed problem. The proposed method utilizes and combines wavelet analysis and artificial neural network (ANN) to detect islanding. Connecting distributed generator to the distribution network has many benefits such as increasing the capacity of the grid and enhancing the power quality. However, it gives rise to many problems. This is mainly due to the fact that distribution networks are designed without any generation units at that level. Hence, integrating distributed generators into the existing distribution network is not problem-free. Unintentional islanding is one of the encountered problems. Discrete wavelet transform (DWT) is capable of decomposing the signals into different frequency bands. It can be utilized in extracting discriminative features from the acquired voltage signals. In passive schemes with a large non-detection zone (NDZ), concern has been raised on active method due to its degrading power quality effect. The main emphasis of the proposed scheme is to reduce the NDZ to as close as possible and to keep the output power quality unchanged. The simulation results from Matlab/Simulink shows that the proposed method has a small non-detection zone, and is capable of detecting islanding accurately within the minimum standard time.     

光伏并网发电系统中孤岛效应的研究和应用

光伏并网发电系统除了具有过压、欠压、过频、欠频等常规保护外,还应具有一种特殊的保护功能——孤岛保护。被动孤岛保护相对简单并易于实现,但当PV系统输出功率和负载匹配时,被动式孤岛检测方法失效。因此,本文采用被动式孤岛检测和主动频率偏移(AFD)相结合的孤岛检测方法,实现了孤岛效应的检测和故障保护。     

对多机并联下应用频移式孤岛检测法面临问题的探讨

针对目前广泛应用的频移式孤岛检测方法——简称频移法,指出当只有部分逆变器采用该方法时,其扰动能力可能不足以撼动孤岛的频率并使其超限,从而提出采用频移法的逆变器比例和频移法正反馈增益的调节等2个问题。针对采用频移法的逆变器比例问题,在最不利情况下进行分析,获得了该比例与逆变器最大过载倍数之间的关系,发现逆变器过载能力越大,采用频移法的逆变器比例可越小;关于频移法正反馈增益的调节问题,本文推导出了正反馈增益与采用频移法逆变器比例的关系,表明正反馈增益必须根据采用频移法的逆变器的比例同步增大。仿真结果验证了上述结论。     

分布式并网发电系统孤岛检测方法综述

分布式发电系统并网运行时处于孤岛状态会对设备造成损坏,影响电力系统安全正常运行,严重时甚至可能会威肋到线路检修人员的人身安全.因此,对分布式发电系统孤岛检测方法的研究具有现实意义.本文综述了分布式并网发电系统孤岛检测的基本方法,并对其进行分类,最后对该领域的研究方向作出了展望.     

自然增长与计划增长

可靠性增长有两种方式：一种是自然增长,另一种是计划增长。前者是不与可靠性目标值相联系的增长方式;后者是受可靠性目标值制约的增长方式。讨论了自然增长和计划增长的概念、内涵和特点,并举例阐述了二者之间的本质区别。     

Improved Active Islanding Detection Technique for Multi-Inverter Power System

Due to the increased penetration of multi-inverter distributed generation (DG) systems, different DG technologies, inverter control methods, and other inverter functions are challenging the capabilities of islanding detection. In addition, multi-inverter networks connecting the distribution system point of common coupling (PCC) create islanding at paralleling inverters, which adds the vulnerability of islanding detection. Furthermore, available islanding detection must overcome more challenges from non-detection zones (NDZs) under reduced power mismatches. Therefore, in this study, a new method called parameter self-adapting active islanding detection was utilized to minimize the dilution effect and reduce NDZs in multi-inverter power systems. The method utilizes an active frequency drift (AFD) method and applies a positive feedback gain of adoption parameters, which significantly minimizes NDZs at parallel inverters. The simulation and experimental outcomes indicate that the proposed method can effectively weaken the dilution effect in multi-inverter networks connecting the distribution system PCC.