Experimental verification of the effect of a voltage‐detection‐based shunt active filter for harmonic damping throughout a power distribution line

This paper is focused on a voltage‐detection‐based shunt active filter for installation on a power distribution system. A main objective of the active filter is to achieve damping of harmonic propagation coming from series/parallel resonance between capacitors for power factor correction and line inductors in the distribution system. The active filter installed at the end terminal of a distribution feeder is controlled in such a way as to present infinite impedance to the external circuit for the fundamental frequency, and to exhibit low resistance for harmonic frequencies. As a result, the active filter acts as a damping resistor for the harmonic propagation, like a 50‐Ω terminator installed at the end of a signal transmission line. It is verified by experiment that the active filter intended for harmonic termination has the capability of harmonic damping throughout the distribution feeder. © 2000 Scripta Technica, Electr Eng Jpn, 133(2): 1–10, 2000     

港口配电系统谐波分析及其治理措施

介绍了港口配电系统的谐波源及其特点,实际测量谐波源的谐波数据分析,港口谐波治理措施。     

Suppression of higher harmonics resonance in a distribution system

There are many PWM control devices, which are higher harmonics current sources, in distribution systems, and higher harmonics cause overcurrents by parallel resonance. To avoid overcurrents, it is necessary to suppress resonance. In this paper, a new suppression method, which uses the effect of source connected points in resonance circuits, is proposed. First it shows that the optimal point, which gives a minimum current amplification degree, is orthogonal to the static condenser voltage. Then, using the eigenvector of the state equation, the participation factor is defined. When the participation factor is zero, the orthogonality condition is introduced. Therefore, the optimal point is obtained with the participation factor. Finally, numerical investigation shows that multiple optimal points usually exist. Therefore, we can choose the most advantageous point as a source‐connected node. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 182(1): 18–29, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22307     

Current waveform control of a high‐power‐factor rectifier circuit for harmonic suppression of voltage and current in a distribution system

This paper presents the input current waveform control of the rectifier circuit which realizes simultaneously the high input power factor and the harmonics suppression of the receiving‐end voltage and the source current under the distorted receiving‐end voltage. The proposed input current waveform includes the harmonic components which are in phase with the receiving‐end voltage harmonics. The control parameter in the proposed waveform is designed by examining the characteristics of both the harmonic suppression effect in the distribution system and the input power factor of the rectifier circuit. The effectiveness of the proposed current waveform has been confirmed experimentally. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(4): 62–71, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10046     

三相四线制变频电网的谐波及无功电流检测

为了满足变频电网提高电能质量的需要,提出一种基于通用瞬时无功理论和正序基波滤波器的谐波、无功及不平衡电流检测方法.针对基于传统通用瞬时无功理论的方法在电源电压畸变或不对称时检测不准确的问题,提出了改进算法.详细分析了正序基波滤波器的特性,采用带有自适应参数的正序基波滤波器提取正序基波电压,采用平均值法获得平均功率,同时应用到改进算法中,适应了电网基频的各种变化,克服了低通滤波器在变频工况下使用的缺陷.在飞机交流变频电网并联APF系统中对所提方法进行了仿真验证,并与Ip-Iq改进法和PHC法进行了对比.研究表明所提方法在电网基频处于不同稳态值或在稳态值间快速变化时均能实现准确,快速地检测.与传统方法相比,具有检测精度高,受变频环境影响小的优点.     

城市轨道交通供电系统谐波分布研究

针对城市轨道交通供电系统,对系统产生的谐波类型进行了分析,指出了谐波的危害性,分析了其特征,并详细分析了不同情况下注入系统节点的谐波大小的计算方法,特别是计算了35kV 系统和 110kV 系统在不同负荷状态下的特征次谐波的大小,并进行了实际的测量,建立系统谐波计算的分布图.对 110kV 侧的谐波电流进行了收集整理和研究,提出了降低谐波的方法和必要性.在此基础上,明确指出轨道交通供电系统应安装滤波装置或者有源滤波装置(APF),这不但可以大大地减小对电网的影响,也可以提高自身系统的运行质量和可靠性.     

Suppression effects of active power filter on harmonics of distribution system including capacitors

Voltage distortion of 6.6-kV distribution systems has been increasing recently especially in commercial areas. Harmonic currents of certain orders are amplified and voltage distortions are generated by the resonance between system impedance and static capacitor under the leading power factor condition. This paper describes the results of a test on suppression effects on model systems and an actual system. The effect of the use of an active power filter on the resonant harmonics of the system including capacitor was verified.     

Calculation of distribution system voltage and power flow state using measured values

This paper describes a techique of calculating voltage and power flow state of a distribution system using the information measured with two or more switches with sensors installed in a distribution system. In the proposed technique, a set of the power distribution section where two or more switches with a sensor are connected is defined as the large section, and the active power and reactive power consumption in the large section are calculated based on measurement information, voltage (RMS), current (RMS), and power factor. Using the simple distribution system model consisting of the large sections, the power consumption of the large section is calculated by the power flow calculation to separate power consumption and power distribution loss. It is distributed to the small sections that constitute the large section, and detailed power flow calculation is performed. Verification of the proposed technique and basic estimation of the calculation error were performed using the simple power distribution system model. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(4): 33–42, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20416     

Effects of output power fluctuation on short‐circuit current of induction‐type wind power generators

Effects of the fluctuation inherent in wind speed are studied by a probabilistic method. The random variation in wind speed is responsible for random behavior in output power and internal voltage of a wind power generator. In case of fault occurrence at the instant of high internal voltage, the resultant short‐circuit current will be big, and vice versa. The DC component is also affected. According to the study, 2.4% and 1.3% increase of short‐circuit current in AC and DC components are observed respectively in a large variation case. This implies that the wind speed variation should be considered for accurate short‐circuit study. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(3): 27–36, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20721     

电力系统谐波检测的FFT加窗插值算法与小波分析方法的比较

对电力系统谐波检测中常用的FFT加窗插值算法和小波分析算法进行了分析比较:FFT加窗插值算法具有检测精度高、实现简单、功能多且使用方便的优点,但计算量较大,因而实时性不够好;小波分析实时性好,能够获取较精确的基波信号,然而对于其他整数次谐波的幅值和相位则较难精确的获得,且难于构造分频严格、能量集中的小波,检测精度也有待改善.并通过仿真实验验证上述结论.     

Development of high voltage harmonic measuring instruments for distribution systems using optical voltage sensor and current sensor

Application of an optical measuring technique was attempted in order to develop harmonic voltage and current measuring instruments for distribution systems. To develop the harmonic voltage measuring system using a Bi₁₂GeO₂₀ crystal as a sensing Pockels cell for high‐voltage distribution lines, zinc oxide elements were adopted as a voltage divider. Also, an optical current sensor system was improved on the harmonic current measuring system using an R₃Fe₅O₁₂ film as a Faraday device. In practical three‐phase distribution systems, the developed high voltage harmonic measuring devices using the optical voltage sensor and current sensor were compared with conventional harmonic analyzers for low voltage. As a result, it was confirmed that the developed high voltage harmonic measuring devices had satisfactory characteristics for practical use. © 1999 Scripta Technica, Electr Eng Jpn, 128(4): 84–93, 1999     

未来型电力系统的广域测量和通信

简述灵活交流输电系统FACTS、新型直流输电系统和全可控电力系统是未来型电力系统新技术的主流；论述基于相量测量单元PMU的广域相量测量系统WAMS的基本功能，並分析了延迟和响应时间等因素对WAMS可用性的影响；指出基于先进光纤通信技术的新一代高速率、低延迟的全光纤通信网络特别适合电力系统的实时测量和控制。     

南南铝业供配电系统无功补偿的技术改造

供配电网合理的无功补偿,能够有效维持系统的电压水平,降低有功线损,减少电能的损耗。以提高南南铝业供配电网功率因数、降低电能损耗为目的,提出了切合公司实际的一种无功补偿方式,即在各分厂的10kV变压器低压侧加装无功补偿设备,实行自动补偿,并在公司挤压厂进行了试点实施,取得了较好的节电效果。     

20kV配电系统的优越性及供电发展模式

综合对不同电压等级配电网的分析比较,指出了20kV电压等级系统的优越性,结合国内外20kV配电网的应用状况和实践经验,对20kV配电网供电发展的模式提出建议。     

配网自动化系统的通信方案设计

结合实例，论述了在配网自动化系统中针对自动化设备采用的以太网接口和自愈环串口两种不同的接口方式所对应的两种通信方案。     

LH8000配电站（房）智能测控系统主要功能

针对配电设备点多面广、相对分散和不易管理的问题,在遵循模块化设计的前提下成功的研制出了新一代的LH8000配电站（房）智能监控系统,推动了我国电网管理自动化、信息化、集中化和智能化的发展。本文对LH8000配电站（房）智能测控系统主要功能进行介绍并做出解释。     

Maximum output power control system of variable‐speed small wind generators

This paper proposes a maximum output power control system for variable‐speed small wind generators. The proposed control system adjusts the rotational speed of a single‐phase AC generator to the optimum rotational speed, which yields the maximum output power according to the natural wind speed. Since this adjustment is performed on‐line in order to adapt to variations in wind speed, the rotational speed of the single‐phase AC generator is adjusted by controlling the generated current flowing in an FET (field‐effect transistor) device, serving as the generated power brake, which is linked directly to the single‐phase AC generator. In order to reduce heat loss from the FET device, a PWM (pulse width modulation) controller is introduced. An experimental model of the proposed control system was built and tested, and the validity and practicality of the proposed control system were confirmed by the experimental results. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(1): 9–17, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20692     

Analysis of the current distortion factor of a three‐phase,three‐wire system

In a balanced three‐phase system, the three‐phase current distortion factor of three‐phase ac power sources has been expressed by applying the conventional single‐phase current distortion factor, which is defined for a single‐phase system. However, in an unbalanced three‐phase system, it is difficult to express the three‐phase current distortion factor for distorted three‐phase ac currents by means of the conventional single‐phase current distortion factor. For instance, the conventional current distortion factors for three‐phase ac currents are usually different from each other in the unbalanced three‐phase system. To solve the above problem, this paper proposes a novel definition of the three‐phase current distortion factor. The proposed three‐phase current distortion factor is quite effective for the unbalanced three‐phase system as well as the balanced three‐phase system. © 2000 Scripta Technica, Electr Eng Jpn, 131(4): 1–10, 2000     

Development of a city‐type compact wind power generation system

It is necessary to use renewable energy, such as photovoltaic, wind power, and biomass energy, from the viewpoint of CO₂ regulation and environmental protection of the Earth. In recent years, the tendency is toward larger wind power generation systems to achieve cheaper electricity. Generators having capacities of 1500 kW to 2000 kW tend to dominate the market. However, a large wind power generation system has limitations in terms of location and can be installed only in the suburbs. At the same time, a city‐type compact wind power generation system, designed for city needs, has more flexibility and can be installed in the residential areas of a city. In this paper, we introduce an original control operation system called a “pump‐up” operation system, designed to effectively use the city wind, and report the results of its field test. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(2): 56–63, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20440