配电线路故障指示器现状分析

如今是一个个电力的时代无处不需要电力的使用,但是巨大的、复杂的输配电线路网络中总会出现多多少少的故障问题,而电路线路出现故障常常也就表现为断路跳闸;只是出现这些故障的时候如果没有检测的设备靠人工去一点一点检查出具体的配电线路故障位置显然是不太实际的;而如今我国的配电线路故障指示器使用的现状又是怎样的,故障指示器的工作原理以及使用过程中需要注意的问题都需要我们去探讨。     

试析电力调控运行系统的优化方法

运行操作系统在电力系统规模不断扩大的过程中日趋复杂化,用户对供电质量以及供电安全提出了更高的要求,因此,电力调度系统管理水平以及调度人员的职业能力需要进一步提升,若电网出现故障或者相关人员操作失误都将出现严重的后果,并且带来较大的经济损失,所以,必须要对电力调控运行系统进行优化。本文主要阐述了电力调控运行的重要性,分析了电力调控运行系统应用的现状及运行中存在的问题,提出了电力调控运行系统的优化措施。     

试析提高电力采集系统故障时刻精度的方法

随着世界经济、科技的发展,电力的使用也是越来越广泛。电力采集系统的准确度则是比较重要的,电力采集系统出现数据故障就是电力发展中的弊端。所以相关部门要想办法来排除电力采集系统数据的故障来使得电力充分地被利用。生活中有的人为减少自家的用电量,则钻电力采集系统的漏洞,想办法使自己家的电表上的数据减少一点,这时相关部门得来的这些数据就是不准确的,这也造成了社会生活中的不公平,也为电力数据的采集带来了一定的弊端。     

基于继电保护隐性故障的电力系统可靠性分析

变电站继电保护运行面临着多种二次回路隐性故障,破坏了继电保护设备安全运行效率.面对早期电力系统改造存在的问题,要从可靠性角度展开深入分析,提出符合继电保护隐性故障防控的可行性对策,提高变电站继电保护作业效率.据此,本文结合电力系统可靠性标准,对继电保护隐性故障提出科学的处理方案.     

基于改进序列模式挖掘算法的告警关联模型

在电力故障发生时,会产生大量的电力故障告警信息数据,如何从电力故障告警信息中挖掘出可靠的关联规则,对后续电力的调度运维有着重要的影响。广义序列模式（Generalized Sequential Pattern,GSP）算法通过增加时间上的约束条件提高算法的效率,适合应用于电力故障告警信息挖掘的场景。针对GSP算法中的关键参数多和不同的参数组合影响算法的准确性和可靠性的问题,将遗传算法与GSP算法相结合,自适应地得到一组较好的参数,将参数代入GSP算法,从而得到更加可靠的关联规则,以此来解决在电力故障告警信息应用中很难为不同的数据集找到合适的参数组合的问题。通过实例验证,电力故障告警信息数据应用遗传算法结合GSP算法能够有效地得到更加准确和可靠的计算结果。     

电力营销实时信息系统建设的实践和思考

在市场竞争日益激烈的今天，电力企业要想持续健康的发展，需要调整电力的营销战略，需．要咖强实时信息的系统建设。资源的交换和共享是以现有的实时数据为基础的，电力营销实时信息系统的建设对于实时数据的利用有着促进作用。笔者从电力营销实时信息系统建设存在的问题进行了分析，并且从自己的角度提出了相应的解决策略。     

电力变压器状态评估及故障诊断方法研究

电力变压器在电力输送系统中占有至关重要的作用,它是电网中能量的传输和转换的重要设备,因此,电力变压器在运行过程中的可靠性和安全性直接影响着电力输送网的稳定性和安全性。在实际的输电网建设过程中,既要选择使用质量可靠、技术过关的变压器,还要随时监控与评估电力变压器的运行状态,以便能及时发现故障而进行维护检修,确保电力变压器的稳定运行。在我国,很多的电力变压器的使用年限都超过了15年,这就导致了在运行时出现一系列的故障,此时就更加需要正确评估电力变压器的运行状态了。本文简述了电力变压器状态评估和故障诊断的几种常用方法,希望能给读者提供一些帮助。     

电力通信在未来智能电网中的应用

电力工业生产的各个环节都贯穿着电力通信网,智能电网能够保证电网的稳定运行。在电力市场中,电力通信将会应用于智能电网中,在电力通信技术中,其有着很高的安全性和功能性,电力通信的性能也要求很高。电力通信在承载方面不能通过运营商通信网络,电力部门必须要根据电力通信的特殊要求来满足用户的需求。整个电力系统生产、传输环节都需要电力通信网的连接,智能电网在我国要积极开展的实践研究工作,随着智能电网的规划和推进,电力通信在未来智能电网中也将被的应用起来。     

基于PCM的保护通道在超高压电力线路继电保护信号传输中的应用

在电力系统中，220kV及以上的超高压电力线路往往是主干的输电线路，由于这些线路的电压高．传输容量大，供电范围广，一旦出现故障将造成重大的事故，危及到系统的安全稳定运行．给人民的生命财产造成巨大损失。因此对这些超高压电力线路．一般都是通过继电保护装置来快速切除发生故障的线路。     

浅谈电力输送故障维护

文章将从电力输送过程中产生的故障问题出发,系统全面地论述在电力输送和运行中关于电力管理与维护的一些措施,然后研究了关于电力输送中产生故障的维护和措施。     

大功率光纤连接器插损测试技术研究

插入损耗是表征光纤连接器性能的重要光学参数,随着光纤在功率传输领域的应用,大功率(>1mW)光纤连接器的插损测量成为目前急待解决的技术.在搭建了测试平台的基础上,采用直接测量法对不同传输功率下光纤连接器的插入损耗进行了测量,试验结果表明插入损耗是随传输能量不断变化的,并存在一个功率值让其达到最小值,文中所用连接器的拐点在0.1W左右.     

配电网线损分析和降损策略分析

发电的电能变成高压通过电网输送至供电地区,之后由变电站降压处理后提供给用户。这个过程不可避免的损失一部分电能,该损失即为线损。在供电过程中线损无法杜绝,但供电企业为了提高管理水平积极思考怎样降低线损,并且在降低线损时增加企业效益。近些年来,供电企业在线损管理中引入新技术,主动实行降损处理,帮助企业实现节能增效。     

Losses in a high-temperature superconductor exposed to AC and DCtransport currents and magnetic fields

Summary form only given, as follows. The development of high-temperature superconductors (HTSs) is for the moment intensive and it is likely that HTSs will be used in different electric devices in a few years. In some of these devices that conductor will be exposed to both AC and DC transport currents and magnetic fields. In the design of electric devices, the power loss is indeed one of the most important parameters. Therefore there is a need of models that predict the power loss in an HTS under application-like conditions. In this paper, the authors present a semi-empirical model including a transport current and an applied magnetic field with both AC and DC components. The semi-empirical model is mainly based on the critical state theory. The results of the model are compared and found to be in good agreement with experimental results obtained with a calorimetric experimental set-up. The power loss was measured on a multi-filamentary Bi-2223 tape as function of transport current and applied magnetic field at a fixed temperature and frequency     

DualBoostPFC电路拓扑的研究

传统的BoostPFC电路的整流桥损耗是通信开关电源的主要损耗之一。无整流桥的拓扑更具有效率优势。由于无桥BoostPFC省略了整流桥模块，效率显著的提高。文中分析了一种高效率的DualBoostPFC的大功率应用，通过实验证明了DualBoostPFC电路效率比传统的BoostPFC提高1个百分点，还介绍了电阻采样控制电路的使用和如何降低EMI干扰。     

On the Matching of Transmission Cavity Stabilized Microwave Oscillators

A matching condition is derived for a transmission cavity stabilized microwave oscillator, which takes account for the power loss in the diode mounting structure. In addition, the power dissipated in the damping resistor--which is commonly used in order to eliminate mode jumping problems--is minimized, thus leading to a useful improvement in both output power and loaded Q-factor of the compound oscillator structure. The effectiveness of the design procedure is finally demonstrated by applying it to a Gunn oscillator realization: at 15 GHz a loaded Q-factor of 6500 could be achieved at the sacrifice of only 2.4-dB overall power loss.     

基于改进遗传算法的配电网无功优化研究

有效降低配电网有功损失是配电网安全、经济运行的重要课题。为解决局部地区网损偏大的问题,文中将改进的遗传算法用于无功补偿优化。在考虑配电网拓扑结构的同时,设计了自适应遗传算子并构造了指数型适应度函数来提升遗传算法收敛速度和精度,充分发挥了遗传算法的全局随机快速搜索能力。优化某16节点算例的结果表明,配电网有功网损由6.76%下降到5.16%,电压达标率从70.61%提高到92.86%,表明该方法能够提高全局寻优精度,改善区域网络电压质量,同时也证明了该改进遗传算法用于无功优化的可行性和实用性。     

QoS based fair resource allocation in multi-cell TD/CDMA communication systems

Abstract-In a wireless multimedia code division multiple access (CDMA) system, the resources in terms of transmission rate and power should be efficiently distributed to each user to guarantee its quality-of-service (QoS) requirements. In, this paper, a resource allocation algorithm which combines packet scheduling and power assignment is proposed to achieve efficient resource utilization under QoS constraints. The packet scheduling is based on the fair packet loss sharing (FPLS) principle, and the power assignment is determined by the received power limited (RPL) scheme. The basic idea of FPLS is to schedule the transmission of multimedia packets in such a way that, all the users have a fair share of packet loss according to their QoS requirements, which maximizes the number of the served users with QoS satisfaction. The RPL scheme minimizes the received power for each packet. Given the propagation path loss, it in turn minimizes the transmitted power as well. The intercell interference from the scheduled packets is also limited in order to increase the system capacity.     

Magnetization Loss and Shield Effect in Multi-Stacked Tapes With Various Stacking Configurations

AC loss is one of the major topics in large AC power applications using high temperature superconductor such as power transformers, transmission cables and fault current limiters because it is closely related to operation efficiency. Multi-stacked tape conductors should be used to transport the large current in those power applications. A research of various arrangements of HTS tapes for multi-stacked tapes has been performed to increase the capacity of transport current in HTS power applications. In this paper, we studied magnetization loss and shield effect from several different arrangements of BSCCO tapes such as Face-to-Face type, regular matrix type (m$times$2) and irregular matrix type. The results show that the magnetization loss of the Face-to-Face arrangement was lower than those of the other matrix types for the same stacking numbers. We think that the result was due to the shield effect by demagnetization of adjacent HTS tapes which were located as face to face.     

一种Ka波段基片集成波导功率合成器的设计

笔者设计了一种结构简单,容易制造的基片集成波导功率分配器／合成器,该分配器／合成器采用渐变微带线——波导的过渡结构,并且厚度只有1．254mm。通过HFSS仿真软件,设计了一个中心频率为35GHz的Ka频段的功率分配器。仿真结果显示此种结构具有极低的插入损耗和较低的回波损耗。     

Minimum current magnitude control of surface PM synchronous machines during constant power operation

The dual-mode inverter control (DMIC) was initially developed to provide broad constant power speed range (CPSR) operation for a surface mounted permanent magnet machine (PMSM) having low inductance. The DMIC interfaces the output of a common voltage source inverter (VSI) to the PMSM through an ac voltage controller. The ac voltage controller consists of three pairs of anti-parallel silicon controlled rectifiers (SCRs), one anti-parallel SCR pair in series with each winding of the motor. In a recent paper a fundamental frequency model of DMIC type controllers was developed using an equivalent reactance interpretation of the in-line SCRs. In this work, the same fundamental frequency model is used to show that the DMIC may have considerable loss reduction benefits even if the motor winding inductance is large. Specifically, it is shown that the SCRs enable maximum watts per rms amp control during constant power operation. The rms motor current can be minimized for any given power level and sufficiently large speed with DMIC. A fixed winding inductance and a conventional inverter can only be optimized for a single speed and power level. The performance predicted by the fundamental frequency model of the DMIC is compared to that of a conventional PMSM drive where the motor has sufficiently large inductance to achieve an infinite CPSR. It is shown that the SCRs can reduce motor current by a factor of 0.7071 at high speed and rated power. This would reduce the motor copper losses by 50% and reduce the conduction losses in the VSI by 29.3%. At less than rated power the percentage of motor/VSI loss reduction enabled by the SCRs is seen to be even larger.