IEEE Standard for Synchrophasors for Power Systems

IEEE Standard 1344, Synchrophasors for Power Systems, was completed in 1995. It sets parameters required to ensure that phasor measurement will be made and communicated in a consistent manner. It specifies requirements for the timing signal used for phasor synchronization and the time code needed for input to a measurement unit. GPS is the recommended time source and IRIG-B is the basic format used for time communication. The standard requires correlating phasors computed from unsynchronized and synchronized sampling to a common basis. Timetagging accurately and consistently is essential for wide area comparison of phase. The standard specifies information exchange and control message formats. These include data output, configuration, and command messages. It includes 7 annexes that discuss the concepts covered in the body of the standard     

Design for ASIC reliability for low-temperature applications

A design for reliability methodology has been developed for electronics for low-temperature applications. A hot carrier aging (HCA) lifetime projection model is proposed to take into account the HCA impact on technology, analysis of parametric degradation versus critical circuit path degradation, transistor bias profile, transistor substrate current profile, and operating temperature profile. The most applicable transistor size can be determined in order to meet the reliability requirements of the electronics operating under low temperatures. This methodology and approach can also be applied to other transistor-level failure and/or degradation mechanisms for applications with varying temperature ranges.     

短路电流计算模式的选择

针对中国电力科学研究院开发的《PSD-SCCPC电力系统短路电流程序》中基于潮流和基于网络的两种短路电流计算模式计算结果存在一定差异的情况,从计算结果真实性、可比性、准确性和对电网的指导作用等方面分析、比较两种计算模式的适用环境。得出结论：基于潮流的计算模式,其计算结果能真实反映实际系统运行情况,适用于电网规划中的网架校验;基于网络的计算模式具有较强的可比性,适用于运行方式的安排和校验。最后提出开展基于网络计算模式修正系数取值研究工作的建议。     

Optimal control schemes for SSSC for dynamic series compensation

This paper presents two novel control schemes for static synchronous series compensator (SSSC) for dynamic series compensation and voltage regulation. The SSSC model comprises a harmonic neutralized multilevel 48 pulse voltage source converter. This paper investigates two novel control schemes for optimal series compensation, which are indirect control (constant reactance control) and direct control (constant voltage control) using pulse width modulation (PWM) switching techniques. The proposed model of SSSC within the power system is performed in Matlab/Simulink using the power system blockset. The performance of the SSSC schemes connected to the 230 kV grid is evaluated in both capacitive and inductive modes of operation under load excursions. The operation of the proposed controllers is also tested in a weak power in order to compare their performance for securing SSSC stability in response to system contingencies.     

Method for calculating iron loss for inductor motors

A method for calculating iron loss in switched-reluctance motors is given. It is necessary to separate the elements of the magnetic system of an electric motor in order to calculate the magnetic flux density according to the turning angle of the rotor. Then, calculations of losses due to hysteresis and eddy current are conducted. The described method can be applied for the verification and design of inductor motors.     

New Algorithms for Computer Based Power System Measurements for Relaying

Abstract

The paper presents two new algorithms for power system measurements for computer relaying. The algorithms involve the design of a discrete-time digital filter which interpolates the signal samples and generates Fourier Co-efficients either by using spectral observations or a functional expansion technique. Sample designs are presented for voltage and current phasor estimation during system transients. A method for including decaying dc and harmonic frequency components in the filter design is also described in the paper. Both computational and on-line test results using an LSI-11/23 microcomputer for power system phasor estimation are presented in the paper.     

寻呼机用电池

寻呼机用电池要求小电流连续放电加上间歇中电流脉冲。使用碱性锌锰电池,不是用其特长,大材小用。高容量电池适于小电流放电,但防漏性能差,不宜用于寻呼机。改变配方后的高功率电池,增加了小电流放电容量,从性能价格比考虑,较适于寻呼机使用。     

真空触头制造设备的改进

介绍了真空触头制造设备改进的几个例子,为真空设备的维护提供了参考。     

带电旁路作业用插拔式快速电缆终端和接头

基于电场有限元数值计算和界面沿面放电试验研究结果,研制了优化绝缘结构设计的插拔式快速终端和接头,其应力锥的绝缘材料采用三元乙丙橡胶,外屏蔽为不锈钢。,终端和中间接头插拔配合的过盈值、复合界面压强值的理论计算值和按IEC、GB、Q/WLT等标准进行型式和补充试验的结果基本一致,寿命可达1000次。     

An Algorithm for Generating Sets of Acceptable Energy Supply Values for Intelligent Systems for Carrying Heavy Trains

Russian Electrical Engineering - This article deals with an algorithm for generating a set of acceptable values of energy supply indicators. This algorithm has been designed for use in intelligent...