弧光接地是中性点不接地配电网中最常见的故障,对电网设备的绝缘性能有严重威胁,从而影响电网运行的稳定性,亟需进行弧光接地故障研究.研究提出弧光接地的物理模拟方法,设计实现弧光模拟装置,通过精确控制放电间隙及放电极移动速度,实现稳定模拟的电弧接地、间歇性电弧接地、弧光渐变等各种弧光接地现象.记录试验波形,并进行分析波形,发现弧光放电的规律.结果表明,物理模拟方法能够可控模拟弧光现象,记录下的波形数据可为处理弧光接地故障提供参考.

在现代电力系统中,柔性直流输电和柔性交流输电技术提高了电能的转换和传输效率,增强了电网的调控能力与灵活性,大幅提升了风、光等新能源的消纳能力,在实现碳达峰和碳中和目标中发挥着重要作用.为了加强理论教学与工程实际的紧密结合,在电力系统动态模拟实验室中搭建了柔性输电系统的物理模型,设计了实验教学内容,并融入现代电力系统综合实验课程的教学中.实践表明,通过实验教学的训练,加深了学生对柔性输电系统理论知识的理解,积累了柔性输电装备的运行经验,提高了学生对柔性输电技术掌握与应用创新能力.

The application of Flexible DC power transmissi on and Flexible AC power transmission technology in modern power system improves the conversion and transmission efficie ncy of electric energy, enhances the control ability and flexibilit y of power grid, and greatly improves the absorption capacity of new energy such as solar energy. Flexible transmission tech nology plays an important role in achieving the goal of carbon peak and carbon neutrality. In order to strengthen the combin ation of theory teaching and engineering practice, the author se ts up the physical model of the flexible transmission system in t he power system dynamic simulation laboratory, designs the ex perimental teaching content, and integrated it into the course o f Comprehensive Experiment of Modern Power System, and carr ied out the teaching experiment. The practice results show that through the training of experimental teaching, the students hav e deepened their understanding of the theory knowledge of flex ible transmission system, accumulated the operation experienc e of flexible transmission equipment, and improved the student s' ability to master and apply the flexible transmission technolo gy.

针对柔性直流配电网现有保护手段应对高阻接地故障灵敏性较差的问题,提出一种基于深度置信网络(DBN)的柔性直流配电网高灵敏故障辨识策略.该策略利用DBN的特征提取能力对正负极暂态电压时域波形数据进行特征提取,以进行故障辨识.利用仿真采集样本数据对DBN进行训练,获取模型最优参数,形成适用于直流配电网故障辨识的DBN模型.基于PSCAD/EMTDC仿真平台对模型性能进行测试.测试结果表明,所提辨识策略对于高阻接地故障具有较好的灵敏性,并且具有较强的泛化能力.

Existing arc generator is usually integrated with a simplified systematic Thevenin equivalent circuit to study the dynamic arc behavior. It cannot be used for the arc fault detection and location research in the neutral non-effectively grounded distribution system (NGDS) because the interaction between the arc fault and the distribution system is ignored. In this paper, one arc generator with additional fault condition control module is proposed, discussed and realized. At the meantime, one scaled-down NGDS is also realized to integrate with our proposed arc generator. The accomplished devices are detailed illustrated and discussed. The effectiveness of the proposed testing platform integrated with the analogous distribution system and the arc fault generator have been validated by the recorded voltage and current waveforms in the experiments

世界上首个特高压三端混合直流输电工程“昆柳龙直流工程”将在2021年建成投运,该工程是将云南大容量水电能源采用先进的直流输电技术送到广西和广东.为了研究特高压远距离架空直流输电线路各种故障特征,探索发现更好的直流保护新判据,分析了直流输电线路的零序电阻和电感频率特性,提出了换流站接地极简化模型,设计了昆柳线、柳龙线两条直流线路模型,建成了一套含接地极的完整分布参数动态物理模型.试验表明,该模型系统达到设计要求,能正确反映原型系统物理特性,可以开展不同故障点的各种类型短路实验,为直流输电技术研究提供了宝贵的试验数据.

研制了一种大容量高精度组合开关和具有多路参考电压的合闸角程序控制器,能够对开关跳合闸角度进行精确控制,实现了对电力系统的短路时刻、变压器励磁涌流实验角度和转换性故障的转换时间等精确控制;能动态模拟再现实际电力系统各种故障波形,能开展0～360°不同时刻的故障实验和故障波形分析.实验表明,该开关的控制精度可由原来的±5 ms提高到±0.1 ms,满足了科学研究实验需要.

This paper designs dynamic model system of a smart distribution network which can be used to analysis on ground fault and experimental study of self-healing control technology of the distribution network, as well as the system test of automation equipment, develops special equipment for carrying out fault location tests and faulty fault line selection test in ungrounded systems, and built the flexible power distribution system dynamic model system. The research achievements have been applied in many universities, power research institutes, ship propulsion system research centers in China.

新能源接入配电网给配电系统继电保护及自动化技术带来了挑战,文中设计了一种能开展接地故障分析及配电网自愈控制技术试验研究、配电网自动化相关装置系统性测试的动态模拟试验平台,研制了开展故障指示器试验和小电流接地选线试验所需的特殊设备,搭建了含新能源和储能的配电系统通用试验模型。实验结果证明了该模拟实验系统的可行性和有效性。

设计开发了一种基于转子位置测量法的动态功角测量装置,该装置不仅能实时跟踪测量发电机的动态功角和转速变化,还能测量电力系统中发电机对不同母线或者不同母线之间的功角.实验表明,该装置具有精度高 、功能多 、灵活性强等特点,能够满足实验教学和科研的需要.

针对配电网故障定位系统研究和试验检测存在的问题,对配电网动态模拟元件进行了研究,研制了升流器、升压器和零序电流互感器等特殊模型实验设备,搭建了一种能开展接地故障分析、小电流接地选线装置试验及故障指示器系统性测试的配电网动态模型.试验表明,该动态模型可以开展故障定位及配电自动化产品的测试研究,成果已推广到国内多所高校和电科院.

In light of the research on and development of the experimental and teaching system for electric power engineering program, an open multifunctional experimental-teaching system is built with the theory and practice of all major professional courses combined for not only their auxiliary teaching experiments, but also the comprehensive application of and research on professional knowledge. Thus students are enabled to train in work on comprehensive experimental topics and application topics using what knowledge acquired to cultivate their hands-on ability, multiple application ability and innovative ability. Applications of the system in China's 100-odd universities are favorably commented on by students for its excellent instructional effects.

The magnetizing inrush possibly occurs when the transformer is energized in the case of no load or a light load. The reason rests with the saturation state or even deep saturation state of the transformer core due to many factors such as inception angles, residual flux, and so on. Both the transformer itself and the power quality in the power system will be adversely impacted by the magnetizing inrush. By utilizing the tertiary winding of a three‐windings transformer, a new technique called ‘magnetizing inrush suppressor’ (MIS) is proposed to eliminate the inrush. When the transformer is switched on, it allows the voltage on the tertiary winding to climb gradually and ensures that the voltages on both sides have the same phase but different magnitudes. In this case, the inrush current can be eliminated successfully. Finally, simulation tests based on PSCAD are performed and analyzed in detail, and the validity of the proposed approach is confirmed. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

The wind energy is one of the fastest growing and most competitive new energy now,it’s quite necessary to develop an experimental platform which can be used for the scientific research and teaching on wind power technology in the laboratory environ-ment.This paper analyzes the characteristics of different wind velocities and wind turbines,proposes a physical model which fit the sci-entific research and teaching,developes a simulated doubly -fed wind power system experimental platform and the capacity of the mod-el is 10kW,The platform can run independently or connect with the power system dynamic simulation system,and can be connected to the WDT -III power system comprehensive experimental teaching system which is widely used in the national universities.The experi-ment results show that the dynamic characteristic of the model is consistent with the theory characteristic of the wind turbine,and can be used for the research and teaching experiment,the experimental platform has been applied in more than ten scientific research insti-tutions and colleges.

The author analyses the infinite bus power source model used in the power system dynamic simulation lab, and make further study on the industry standard for the Dynamic Test of the Power System Protective Products, then introduced a design scheme for the infinite bus system dynamic model, based on which an infinite bus system model for different voltage levels is proposed. The experimental results show that the proposed model can well reflect the dynamic process of the prototype.

This paper aims at the appropriate applications of two important current differential protection criteria by quantitative analyses. Combining theoretical analysis with simulation tests, the overall performances of two typical percentage differential protection criteria are compared in terms of the operation sensitivity and security. First, with appropriate parameter settings, the comparative sensitivity analysis between the phase‐current‐based criterion and the superimposed‐component‐based criterion is done. Further, the security of these criteria is compared, and some disadvantages of the criterion based on phase current directly are reported. The performance of the criteria during the current transformer (CT) saturation when experiencing heavy external faults are studied, and some valuable findings are reported as well. With the conclusion drawn from this paper, the applications of both criteria can be arranged more reasonably. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

While the high‐resistance earth fault frequently occurs on extra high voltage (EHV) transmission lines, existing protection schemes show great limitation for coping with this kind of fault scenario when the fault resistance is very high. In this paper, a novel protection methodology combining the measured impedance of the two ends is introduced, and a so‐called summation impedance protection, making use of this critical information, is thus put forward and assessed. Emphasis is placed on the principle of the summation impedance protection and its adaptive thresholds. A simulation model based on EMTDC/PSCAD, by which the performance of the summation impedance protection is evaluated, is then established. As confirmed by quantitative theoretical and experimental studies, the results indicate that the proposed protection scheme works well even when the fault resistance is extremely high under the internal fault condition, and it keeps itself from maloperation as an effect of its adaptive thresholds wherever an external fault occurs. These results highlight the necessity to work in conjunction with the existing main protections of transmission lines, by which means an enhanced ability to cope with the high‐resistance single‐phase earth fault can be achieved. © 2015 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Conventionally, the Doubly-fed Induction Generator (DFIG) has no impacts on the arrangement and the setting of the feeder overcurrent protection in the large-scale, concentrated wind farm, since the DFIG has long been regarded as a normal load under the fault conditions. As a result, existing overcurrent protection equipped on a sound feeder may mal-operate when a fault occurs on adjacent feeders, if the DFIG feeding current on the corresponding sound feeder is high enough. To prevent this, further investigation is thereby undertaken in this paper. The characteristics of the DFIG feeding current is analyzed under various fault conditions in the first place. Secondly, the feeder overcurrent protection is set according to currently-applied principles, based on which the corresponding mal-operation zone and the mal-operation risk are calculated under different system operation conditions. It can be deduced from the results that a reasonable DFIG crowbar resistance value and an optimized wind farm arrangement can be of positive effect to limit the mal-operation risk. Directional element must be configured for the existing protection if above countermeasures are not available and the mal-operation risk still exists.

鉴于电力技术的高速发展对物理模拟试验系统提出了更多新的要求,提出了新型电力系统模拟试验系统,分析了系统的各部分主要功能,并基于对模型系统与原型系统一致性的理论分析,以典型的单机—无穷大系统为例,分析了该系统在试验过程中出现的物理现象和参数变化过程.结果表明,线路发生两相故障时,故障超前相和落后相电流的大小关系取决于故障前发电机向系统输送的负荷大小;保持发电机电势不变,增加有功功率输出,当线路阻抗大于发电机同步电抗时发电机处于迟相运行,反之则处于进相运行.

Accompanied by the popularization of EVs, the planning of electric vehicle (EV) charging stations becomes an important concern of distribution network planning. In this paper, the load density method is introduced to determine the optimal capacity of the EV charging stations in the areas to be planned, and the difference between 1 and the weight coefficients obtained by the analytic hierarchy process (AHP) method is used to calculate the cost coefficients of the charging station. The objective function of the optimal distribution network planning model should be the minimal cost of the fixed investments, the operational costs and the maintenance costs including the substations, charging stations and feeders. In this model, the effect of vehicle-to-grid (V2G) is considered, i.e., the EV is respectively treated as both the load and the source. Moreover, the electricity price volatility has been taken into consideration. In this case, EV owners can be guided to charge and discharge EV orderly. The ordinal optimization approach is applied to get the best solution. The results of the case study based on IEEE 54 nodes model show the feasibility and effectiveness of the proposed model.