和谐校园建设中高校管理法治化的问题及对策

文章主要探讨了和谐校园建设中高校管理的程序和实体法律问题,提出要实现和谐校园建设的整体目标,必须从法制保障建设、法治文化建设、行为规范建设以及权力制约等方面着手,将高校管理纳入到法治化的进程。     

A CMOS DCO design using delay programmable differential latches and a novel digital control scheme

A novel 16-bit CMOS digitally controlled oscillator (DCO) is described. This CMOS DCO design is based on a delay programmable differential latch and a novel digital control scheme which yields improved phase noise characteristics. Simulations of a 4-stage CMOS DCO using the 0.5 μm Agilent CMOS process parameters achieved a controllable frequency range of 750 MHz–1.6 GHz with a monotone tuning range of around 1 GHz. Monte Carlo simulations indicate that the time-period jitter due to random supply voltage fluctuations is under 250 ps for worst-case considerations. Also, phase noise was found to be in the range of −175 dBc at a frequency of 600 KHz from the carrier at 1.5 GHz (for digital control word of 1512 H) after numerous iterations of Monte Carlo simulations. FFT analysis indicate a total harmonic distortion (THD) of around − 57 dB for the DCO output signal. This CMOS design would thus provide considerable performance enhancement in digital PLL applications.     

非正弦情况下无功功率的测量

本文提出采用单片微机组成检测系统,在时域,频域两个方面实现对非正弦情况下的有功功率,无功功率各个分量等各项参数的测量,并阐述测量原理、算法、硬件组成和框图。     

并联补偿装置运行中的异常现象及对策

就并联补偿装置运行中较易发生的异常现象和合闸涌流引起的过电压、并联补偿装置切除时开关重燃引起的过电压以及系统高次谐波和投入空载变压器对并联补偿装置的影响和危害,进行了详细的分析,提出了有针对性的解决办法.     

基于BP神经网络的高精度基波频率检测方法研究

电力系统谐波检测过程对基波频率的检测精度要求越来越高。针对这一需求,在对比了各种常用基波检测方法后,提出一种基于BP(Back Propagation)神经网络的高精度基波频率检测方法。既通过充分有效地学习和训练,构建出了合理的BP神经网络模型,并利用Matlab软件对其进行仿真验证。结果表明,算法对频率测量精度达10-3~10-5,并且任一频率(50 Hz除外)BP神经网络算法的频率测量都比加汉宁窗的FFT算法高2~3个数量级。     

48脉波整流变压器组的谐波电流

分析了48脉波整流变压器组中的谐波电流,说明了多脉波整流变压器对馈入电网的谐波电流的影响.     

谐波齿轮传动模糊可靠性设计

介绍了将模糊可靠性设计应用到谐波齿轮传动中,确定了隶属函数,推导了模糊可靠度公式,给出了各项强度计算的功能函数和标准差。举例说明计算过程,计算结果说明了由于同时考虑了变量的随机性和模糊性,在相同条件下模糊可靠度大于常规可靠度。     

发电机励磁变压器几个关键问题的分析

以三峡发电机励磁变压器为例,对励磁变压器几个关键问题进行了分析。     

Implementation of the shunt harmonic voltages compensation approach

Instead of injecting harmonic currents to compensate those drawn by distorting loads, in this paper a shunt active filter is used for generating harmonic voltages to compensate harmonic voltages at the point of common coupling; the main advantage in using such a compensation approach is that, when the aim is to reduce or eliminate the harmonic voltages at the point of common coupling only one active filter is required. For determining the harmonic voltages such a filter must generate, two simple and practical methods are proposed in this paper; the effectiveness of these methods was evaluated using a 1-kW prototype of an active filter operating according to the shunt harmonic voltage compensation approach. In addition, the laboratory results were comparable to those obtained with the ATP-EMTP simulation software.     

浅议发电厂电能质量与监测分析

谐波是电能质量的5项指标之一,也是目前问题比较多、受用户影响比较大的一项指标。因谐波超标而损坏电器和给电网安全运行带来的事故时有报导,并给电能计量带来误差。本文介绍了淮北发电厂进行电能质量监测的目的和工作开展情况,简要论述了谐波是如何产生的,谐波的出现对电力设备的危害,列出了部分监测数据,并对监测数据进行了分析,提出了防范建议。