高压电网线路零序和距离保护计算实用程序

介绍了高压电网线路零序和距离保护计算实用程序，在广东省２２０ｋＶ后备保护的整定计算中发挥了作用，给出其整定原则和程序流程图。

计划中的高压电网线路

如果把整20世纪各个国家所有搭建的电网都连接起来，不难发现世界各个角落只要是有人的地方几乎都被电网连接在了一起。改善电网平衡需求和供给间波动的能力，需要建设新的高容量传输线路来大面积分配电力。

输电及高压配电架空线路检修及施工

输电及高压配电架空线路上,除个别线路装有少量管形避雷器外,只有部件,没有设备,因此,检修的特点是不管停电检修,还是带电检修,都是现场就地检修,没有将部件拆下送往检修车间检修,检修好后再运回现场装上的。而且所谓现场,也和变电设备检修现场真正是一个点完全不同,常常是几公里、几十公里的一条线。重点讨论了输电及高压架空线路的检修周期、检修管理、施工中注意的几个问题。

高压输电线路路径选择新方法探索

本文提出了用目标规划方法选择输电线路路径的两步求解法,即一是利用广义的复搜索法选择K条最小费用路径;二是考虑社会和环境因素(SEC)对路径选择的影响。将SEC问题表示成0-1目标规划模型,用隐枚举法解决。该两步求解法应用到两类问题的结果表明,假如能找到可接受的SEC标准,该方法用于路径的选择是合适的。

输电高压线路的检修与维护

输电高压线路,除个别线路装有少量管形避雷器外,只有部件,没有设备,因此,检修的特点是不管停电检修,还是带电检修,都是现场就地检修,没有将部件拆下送往检修车间检修,检修好后再运回现场装上的.而且所谓现场,也和变电设备检修现场真正是一个点完全不同,常常是几公里、几十公里的一条线.重点讨论了输电及高压架空线路的检修周期、检修管理、施工中注意的几个问题.

高压输配电架空线路检修及施工分析

电力系统是维持人们正常生活必不可少的一部分,同时其稳定运行也是社会发展的基础所在。而其中输配电线路的架空部分的检修需要工作人员重点关注,线路运行异常可能会造成严重的问题,甚至会引发连锁效应。相较于其他种类的线路来说,高压输配电线路的检修较为严格,因此深入分析架空线路的检修具有现实意义。本文重点分析高压输配电架空线路运行中可能出现的问题,并对检修项目深入研究,提出与检修项目有关的参考意见。

基于改进灰狼算法的多操纵面无人机在线路检测中的可行性研究

控制分配是用于解决多操纵面飞行器控制冗余问题的常用方法之一,其目的是在一定的约束条件下,将控制指令合理地分配到各个执行机构,从而提高飞行器的控制性能,且飞行器在工作中会出现操纵面故障的问题。在传统灰狼算法的基础上进行改进,并将其应用于解决控制分配和控制重分配问题,还将其实际应用到高压电塔的线路检修检测中。

阐述送电线路建设中对环境保护的影响及防治措施

随着环境保护意识及对国民经济可持续发展意识的提高，送电线路设计工作者和建设业主越来越认识到保护环境的重要性，并在设计和建设过程中得到重视。架空送电线路是一种洁净能源设施，在运行的全寿命过程中，不产生和排泄有毒化学污物，但是在运行时产生电磁辐射和无线电干扰、连续电磁性噪声，建设期可能造成基础土石方开挖引起的水土流失、植被破坏、拆迁改造等问题。

NEW PRINCIPLE FOR DIRECTIONAL COMPARISON CARRIER PROTECTION OF EHV TRANSMISSION LINES

The increasing scale and complexity of power systems require high performance and high reliability of power system protection.Protective relaying based on directional comparison with power line carrier or microwave channels is the most suitable protection scheme for long distance EHV transmission lines and is widely used in power systems.The key element of such protection is a directional relay used to discriminate the fault direction.In order to overcome the disadvantages of conventional directional relays,the authors of this paper put forward the directional comparison carrier protection based on the artificial neural network(ANN).The protection is extensively tested using electromagnetic transient program (EMTP) under various electric power system operating and fault conditions.It is proved that the directional comparison carrier protection based on ANN,which can recognize various fault patterns of the protected transmission line(such as fault direction,fault phases etc.)correctly in any kind of operating and fault conditions and the whole process,is satisfactory for EHV transmission line protection.

Nonlinear dynamical response of high-voltage transmission lines based on cable dropping

In order to study the dynamic response of high-voltage transmission lines under mechanical failure, a finite element model of a domestic 500-kV high-voltage transmission line system is established. The initial equilibrium condition of the coupling system model is verified by nonlinear static analysis. The transient dynamic analysis method is proposed to analyze the variation law of dynamic response under cable or insulator rupture, and the dynamic response of structural elements next to the broken span is calculated. The results show that upper crossarm cable rupture has no effect on cable tension at adjacent suspension points, but it has a significant influence on tension in the insulator and the tower component of the upper crossarm next to the broken span. The peak tension in the conductor of the upper crossarm at the suspension point exceeds the design value under insulator rupture. Insulator rupture has no effect on the tower component of the upper crossarm, but it has a significant influence on insulator tension of the upper crossarm. Insulator rupture should be taken into account in the design of overhead transmission lines. The research results can provide a theoretical basis for the design of transmission lines.

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Modeling of electrode system for three-phase electric arc furnace

To simulate the process of electrode operation, a dynamic model describing the electrode system of three-phase electric arc furnace was developed. This new model can be divided into three submodels in terms of the practical situation. They are the power supply system model the electric arc model and the hydraulic actuator system model. According to the basic circuit theory, the power supply system model where the high voltage transmission circuit and mutual inductances were considered, was set up. The electric arc model, which was novel for the electrode control, served as the electrical load and was connected to the power supply system model. The hydraulic actuator system model consists of the proportional valve part that is modeled to capture the dead-zone nonlinear characteristics and the hydraulic cylinder part where the impact of the load force is taken into account. By comparing simulation data and actual data, the results show that the electrode system model is proved to be accurate.

Geospatial Solutions in Practice for Smart Grids

Recently, smart grid solutions have started to extend the visibility of the electrical grid to the entire network; including high voltage transmission lines, medium voltage distribution networks, and the low voltage networks to households. The typical data monitored includes： voltage, current, phase, and power measurements, together with network events and alarms. This paper analyses the key challenges facing smart grid solutions in providing effective access to large volumes of sensory data that is distributed over a large geographic area. A case study is described that outlines how the use of geospatial technology together with Web 2.0 technologies may be applied to improve user access and control to this data. The results show that a geospatial solution provides an effective mechanism for visualizing telemetry data monitored within the smart grid.

Novel Algorithm for Estimating the Distance of Open-Conductor Faults in HV Transmission Lines

This paper presents an ANN （artificial neural networks）-based technique for improving the performance of distance relays against open-circuit faults in transmission networks. The technique utilizes the small capacitive current measured in the open-phase plus the currents in the two healthy phases in calculating the open-circuit fault distance. The results obtained show that a distance relay with the proposed scheme will not only be able to detect the open-conductor condition in HVTL （high voltage transmission line） but also to locate the place of this fault regardless the value of the pre-fault current loading. There is no need for especial communication schemes since the existing media could work properly for the needs of the proposed technique.

Analysis of the Correlation between the Level of Contact Degradation and the Dynamic Resistance Curve in Circuit Breakers

The DRM （dynamic contact resistance measurement） in high voltage circuit breakers is a manner of evaluating the internal ageing condition of the chamber. DRM is similar to static contact resistance measurement testing, but instead of measuring a single value when the breaker contacts are closed （static value）, the ohmic resistance is measured at various contact positions, from the beginning of the contact opening until a complete separation of the contacts. The relationship between the contact resistances of the new circuit breaker and the ageing circuit breaker in operation provides subsidy for the evaluation of both the main and arcing contact conditions. This research aims to analyze the correlation between the various levels of degradation of the contacts and the configuration of the DRM curve. This work considers curve samples from new acceleration tests. breaker chamber contacts and different levels of degradation by

A Novel Technology for Generation of Electricity and Cold by Using Energy Potential of Transmission Line＇s High Pressure Gas

The main objective of this paper is to develop a novel technology for combined generation of electricity and cold by using energy potential of transmission line＇s high pressure gas. For this purpose, the reduction of high pressure of the gas in gas distribution station instead of useless expansion throttling process is suggested to realize by adiabatic expansion, which is executed in a gas expanding turbine. Herewith, the gas distribution station is turned into energy and cold generating plant. Simultaneous operation of energy and cold generating plant is described. A method and appropriate formulas for determination of design characteristics of considered plant are suggested. A new method for reveres order of calculation and design of the cold store based on the use of expanded cold gas as cooling agent is developed. Calculations and analysis prove high energy efficiency of suggested technology, the wide use of which will provide significant production of cheap electricity and cold and as well as reduction of fossil fuel consumption.

Safe Distance for Inspection of 1 000 kV UHVAC Lines with Helicopter

Helicopter inspection of ultra high voltage （UHV） transmission lines has unmatched advantages compared to manual work due to the inspection angle and high-tech equipment on board, especially in detailed inspections of tower heads and defect-detections in virtue of infrared/ultraviolet techniques. This paper deals with some key technical problems in the inspections of i 000 kV UHVAC lines with a helicopter, such as the safe distance of live-line working, electromagnetic field intensity and flight control. Based on the study results, a set of UHV line inspection methods was worked out and applied to the inspection of live UHV lines.

Modeling of an ionized electric field on the building near the UHVDC transmission line

In this paper,a 3D upstream finite element method is developed to analyze the ionized electric field around the UHVDC transmission lines including the building near it.The ionized electric field around the building is reduced due to the shielding effect of the building and the shielding distance is about three times its height.The ionized electric field including the human body model on the building and away from the building is also taken into account.The ionized electric field distortion ratio of the human body model is discussed in this paper.The distortion ratios for the positions on the building are less than those on the ground.

Fault component integrated impedance-based pilot protection scheme for EHV/UHV transmission line with thyristor controlled series capacitor(TCSC) and controllable shunt reactor(CSR)

This paper analyzes the fundamental frequency impedance presents a novel transmission line pilot protection scheme characteristic of a thyristor controlled series capacitor （TCSC） and based on fault component integrated impedance （FCII） calculated for a transmission line with TCSC and controllable shunt reactor （CSR）. The FCII is defined as the ratio of the sum of the fault component voltage phasors of a transmission line with TCSC and CSR to the sum of the fault component current phasors where all the phasors are determined at both line＇s terminals. It can be used to distinguish internal faults occurring on the line from external ones. If the fault is an external one the FCII reflects the line＇s capacitive impedance and has large value. If the fault is an internal one on the line the FCII reflects the impedance of the equivalent system and the line and is relatively small. The new pilot protection scheme can be easily set and has the fault phase selection ability and also it is not affected by the capacitive current and the fault transition resistance. It is not sensitive to compensation level and dynamics of TCSC and CSR. The effectiveness of the new scheme is validated against data obtained in ATP simulations and Northwest China 750 kV Project.

Experimental and Theoretical Analysis of an Optical Current Sensor for High Power Systems

A magneto-optical sensor, using a dual quadrature polarimetfic processing scheme, was evaluated for current metering and protection applications in high voltage lines. Sensor calibration and resolution were obtained in different operational conditions using illumination in the 1550-nm band. Results obtained indicated the feasibility of interrogating such sensor via the optical ground wire （OPGW） link installed in standard high power grids. The polarimetric bulk optical current sensor also was theoretically studied, and the effects of different sources of error considering practical deployment were evaluated. In particular, the interference from external magnetic fields in a tree-phase system was analyzed.