Steady-state operating conditions of very long EHVAC cable lines: Two case studies

The paper deals with the operation of very long EHV AC cable lines in a well-developed bulk power system, by simulating two 400 kV-50 Hz single circuit cable lines, 80-100 km long, installed at different locations of the Italian transmission network, both standing alone and in parallel to an existing overhead line. The power transmission limits of the considered cable lines are assessed analytically, as well as the required amount of shunt compensation and its location, at line terminals or also at mid-line; a criterion for sizing mid-line shunt compensation is also proposed. In order to check theoretical analyses carried out by analytical formulas, AC load flow simulations of the transmission network with the hypothetical cable lines in place are evaluated, referring to severe loading conditions in both normal and post-contingency operation. Open-ended cable operation and shunt compensation contingencies are also addressed. Results show that power transmission limits due to cable ampacity and higher active power flows due to low cable reactance do not pose special constraints on the operation of the powerful network under examination. Appropriate shunt compensation minimizes the effects of surplus cable reactive power, allowing to operate long 400 kV-50 Hz cable lines (up to 100 km at least) with reactors at line terminals only. Moreover, if shunt compensation is installed also at mid-line, operating capabilities of the long cable lines are enhanced and losses reduced.     

对高压并联电容器组中电容器单元安装间距的研究

通过对各种容量并联电容器,在不同安装间距下的温升研究,确定不同的安装间距对电容器组温升的影响,本项试验研究成果,可作为《并联电容器装置设计规范》修订相关条文的依据,为电容器和电力用户的并联电容器成套装置的设计提供参考。     

500kV壳式三相并联电抗器开发设计

介绍了500kV壳式三相并联电抗器的设计开发情况,其中包括壳式并联电抗器的基本设计、振动计算、电场计算分析和结构上的抗震措施等内容。     

特高压1000kV并联电抗器首端引线两种出线方式的分析与研究

本文中作者介绍了1 000kV并联电抗器首端两种引线出线方式的结构,利用Elec Net软件对两者进行了仿真分析,并进行了经济性对比。     

并补CSR特高压线路静态稳定受限的机理分析

针对在电力系统中越来越多地投入使用并联电抗器的情况,为正确认识并联电抗器的作用,采用基于波过程和二端口网络理论相结合的方法,对并联电抗器降低特高压输电线路静态稳定性的机理进行了研究,通过改变并联电抗器的某些重要参数,分析特高压输电线路静态稳定功率极限的变化情况,得出了一些重要结果。     

并联型有源电力滤波器直流电容电压的控制

控制有源电力滤波器(APF)直流侧电压为适当值是保证其具有良好补偿性能的一个重要因素,以并联型有源电力滤波器交流和直流侧瞬时功率平衡为基础,对并联型有源电力滤波器直流电容平均电压与脉动电压的变化规律进行研究,分析了它们对并联型有源电力滤波器性能的影响。为了克服这种影响,提出了在补偿电流中注入基波有功电流和增大直流侧电容量控制直流电压稳定的一种方法。仿真结果验证了所提出方法的正确性和有效性。     

直流耦合并馈PDM广播发射机

本文通过在１ＫＷ发射机上作“直流耦合并馈ＰＤＭ机”的过渡试验，介绍该机的基本原理及其特点，并把它与我国正在运行的几种串馈，并馈ＰＤＭ发射机作比较，指出其优、缺点及其应用前景。     

双极堆式电池中的漏电电流

本文根据28篇参考文献简短地述及双极电堆中漏电电流的产生、测量、计算及它的减小和消除。     

Design and analysis of a flat gain and linear low noise amplifier using modified current reused structure with feedforward structure

In this paper, a Low Noise Amplifier (LNA) with the current reused topology is proposed for wideband applications. To increase input impedance matching common source with inductive degeneration and RC shunt feedback structure is used. To extend the bandwidth, inductive series peaking technique is utilized. In the next stage, two parallel structure is hired to have a high voltage gain with low power consumption in addition to improve linearity. Also, by using the self-forward-body-bias (SFBB) technique, supply voltage is reduced and as a result power consumption is decreased further. The proposed LNA exhibits the high and flat gain of 14.7–15.4 ​dB, input return loss of less than −11 ​dB and noise figure range of 2.3–4.4 ​dB from 1 ​GHz up to 8 ​GHz. It consumes 5.4 ​mW from a 1.2 ​V power supply. The achieved IIP3 range for the proposed LNA is 0 ​dBm up to +2.7 ​dBm. The proposed LNA occupies 0.45 ​mm² in 0.18-μm CMOS technology.