Current control for a shunt hybrid active power filter using recursive integral PI

This paper presents a current control method for a shunt hybrid active power filter （HAPF） using recursive integral PI algorithm. The method improves the performance of the HAPF system by reducing the influence of detection accuracy, time delay of instruction current calculation and phase displacement of output filter. Fuzzy logic based set-point weighing algorithm is combined in the control scheme to enhance its robustness and anti-interference ability. The proposed algorithm is easy to implement for engineering applications and easy to compute. Experiment results have verified the validity of the proposed controller. Furthermore, the proposed recursive integral PI algorithm can also be applied in the control of periodic current as in AC drivers.

A novel digital control strategy of three-phase shunt active power filter under non-ideal mains voltages

A novel control strategy for three-phase shunt active power filter (SAPF) was proposed to improve its performance under non-ideal mains voltages. The approach was inspired by our finding that the classic instantaneous reactive power theory based algorithm was unsatisfactory in terms of isolating positive sequence fundamental active components exactly under non-ideal mains voltages. So, a modified ip-iq reference current calculation method was presented. With usage of the new method, not only the positive sequence but also the fundamental active current components can be accurately isolated from load current. A deadbeat closed-loop control model is built in order to eliminate both delay error and tracking error between reference voltages and compensation voltages under unbalanced and distorted mains voltages. Computer simulation results show that the proposed strategy is effective with better tracking ability and lower total harmonic distortion (THD). The strategy is also applied to a 10 kV substation with a local electrolysis manganese plant injecting a large amount of harmonics into the power system, and is proved to be more practical and efficient.

Open-circuit fault diagnosis and fault tolerance for shunt active power filter

The open-circuit fault of the power switches in shunt active power filter(SAPF) would exacerbate the harmonic pollution of power grid, and degrade the reliability of the devices and system. A fault diagnosis method is proposed based on reference model and an over-modulation strategy under hardware fault tolerance for SAPF. First, a mathematic model is established for SAPF. Second, the residuals are generated by comparing the outputs of reference model and those of actual model, and open-switch fault is detected and diagnosed by residual evaluation. After that, hardware fault tolerance is performed with the three-phase four-switch(TPFS) topology to isolate the faulty phase. Finally, the over-modulation strategy is proposed to increase the voltage transfer ratio of the TPFS topology. Simulation and experimental results verified the feasibility and effectiveness of the proposed method.

An Efficient Particle Swarm Optimization Technique for 4-Leg Shunt Active Power Filter

This paper describes the mitigation of harmonics in source and neutral current in three phase four wire system based on 4-leg shunt active power filter under balanced and unbalanced load conditions. Particle Swarm Optimization (PSO) and conventional Proportional Integral (PI) controller are used as control techniques to analyze the control performance of 4-leg shunt active power filter. The synchronous reference frame (SRF) method is used to extract reference current in 4-leg shunt active filter. The Hysteresis Current Controller (HCC) is used to generate gate pulses for Voltage Source Inverter (VSI) based 4-leg shunt active power filter. The proposed PSO technique gives less percentage of Total Harmonic Distortion (THD) value in source and neutral current and settling time of the DC capacitor voltage compared to conventional PI controller technique. The model of the proposed system performance was validated using MATLAB/Simulink environment.

Harmonic Reduction in Wind Power Generating System Using Shunt Active Filter with SPWM Technique

Due to environmental conditions, the wind power generation is fluctuating in nature. This affects the electrical network interconnected with these systems. When the wind power generators are connected to the nonlinear loads, there is distortion in the waveform. These distortions should be within limits according to national and international guidelines framed for power quality. This paper presents a mitigation technique with a shunt active filter, which reduces harmonic distortion to the permitted limit. Sine pulse width modulation (SPWM) control scheme is used to control shunt active filter. This technique eliminates harmonic distortion and maintains unity power factor. The simulation for proposed method is carried out using MATLAB/SIMULINK and results are validated.

A Novel Fuzzy—Adaptive Hysteresis Controller Based Three Phase Four Wire-Four Leg Shunt Active Filter for Harmonic and Reactive Power Compensation

This paper presents a fuzzy logic based three phase four wire four-leg shunt active power filter to suppress harmonic currents. Modified instantaneous p-q theory is adopted for calculating the compensating current. Fuzzy-adaptive hysteresis band technique is applied for the current control to derive the switching signals for the voltage source inverter. A fuzzy logic controller is developed to control the voltage of the DC capacitor. Computer simulations are carried out on a sample power system to demonstrate the suitability of the proposed control strategy, for harmonic reduction under three different conditions namely, ideal, unbalance, unbalance and distorted source voltage conditions. The proposed control strategy is found to be effective to reduce the harmonics and compensate reactive power and neutral current and balance load currents under ideal and non-ideal source voltage conditions.

Simulation and reliability analysis of shunt active power filter based on instantaneous reactive power theory

This paper first discusses the operating principle of instantaneous reactive power theory. Then, the theory is introduced into shunt active power filter and its control scheme is studied. Finally, Matlab/Simulink power system toolbox is used to simulate the system. In the simulation model, as the most common harmonic source, 3-phase thyristor bridge rectifier circuit is constructed. The simulation results before and after the shunt active filter was switched to the system corresponding to different firing angles of the thyristors are presented and analyzed, which demonstrate the practicability and reliability of the proposed shunt active filter scheme.

Particle swarm optimization algorithm for simultaneous optimal placement and sizing of shunt active power conditioner(APC)and shunt capacitor in harmonic distorted distribution system

Due to development of distribution systems and increase in electricity demand,the use of capacitor banks increases.From the other point of view,nonlinear loads generate and inject considerable harmonic currents into power system.Under this condition if capacitor banks are not properly selected and placed in the power system,they could amplify and propagate these harmonics and deteriorate power quality to unacceptable levels.With attention of disadvantages of passive filters,such as occurring resonance,nowadays the usage of this type of harmonic compensator is restricted.On the other side,one of parallel multi-function compensating devices which are recently used in distribution system to mitigate voltage sag and harmonic distortion,performs power factor correction,and improves the overall power quality as active power conditioner(APC).Therefore,the utilization of APC in harmonic distorted system can affect and change the optimal location and size of shunt capacitor bank under harmonic distortion condition.This paper presents an optimization algorithm for improvement of power quality using simultaneous optimal placement and sizing of APC and shunt capacitor banks in radial distribution networks in the presence of voltage and current harmonics.The algorithm is based on particle swarm optimization(PSO).The objective function includes the cost of power losses,energy losses and those of the capacitor banks and APCs.

多谐波源接入的城市配电网SAPF优化配置方法

针对分布式光伏和电动汽车充电设施等新谐波源渗透率高及分散接入造成的城市配电网谐波污染分散化与全网化问题,构建一种兼顾配电网谐波治理成本与治理成效的并联型有源电力滤波器选址定容双层优化模型。首先,外、内层模型分别以配电网谐波治理成本最小和电压畸变率最低为目标函数;然后,采用粒子群优化算法和遗传算法分别求解,实现配电网谐波治理效益最高的目标;最后,选取IEEE 33节点系统进行仿真,验证了所建模型对配电网谐波治理装置优化配置的有效性。

铯原子钟电子倍增器可调高压电源设计

电子倍增器用来放大并输出铯原子的跃迁信号。倍增器电源是其重要组成部分,针对电子倍增器在增益变化及衰减情况下的供电需求,提出了一种基于分流调整电路结合倍压整流电路的高压电源设计方案,该方案在低压部分采用分流调整技术实现了电源输出电压控制;采用变压器结合多级倍压整流电路对电压放大输出,实现了电源可调电压范围在-306~-3 150 V和低输出纹波,电源的遥测电路实现了输出电压遥测。星载铯原子钟经过长期在轨测试,测试结果表明,本设计的电源在控制范围内实现了宽范围电压输出和遥测,低于3.23 V的电源纹波,保证了铯原子钟稳定度指标。

并联电抗器补偿方案对500 kV海底电缆沿线过电压的分布影响

交流海底电缆是海上风电场交流输电技术的重要组成部分,但其充电电流问题限制了其在远距离、大容量海上风电中的应用。文中基于HYJQF41-F290/500 kV型号的单芯交流海底电缆,研究了该电缆在远距离、高压输电中不同工况下的沿线过电压分布情况。首先,建立该电缆的仿真模型,并对其参数进行修正。然后,针对并联电抗器的不同补偿度,对单端补偿、两端补偿等配置方案下并联电抗器的容量进行分析计算。最后,基于高压、远距离风电场模型中单相接地故障、合分闸等工况,对不同无功补偿方案下海底电缆沿线过电压的分布规律进行仿真研究。研究结果表明,海底电缆的最大过电压随着补偿方案的不同而出现在不同的位置。基于此,文中给出了在不同补偿方案下高压海底电缆选型以及变电站设备绝缘水平设计时过电压的选取方法,对工程实际具有一定指导意义。

基于虚拟导纳的LCL型并联有源电力滤波器鲁棒电流控制

基于电网电流和逆变侧电流的双环电流控制策略因其固有的有源阻尼作用而成为LCL型并联有源电力滤波器的研究热点,但控制回路中不同有源阻尼共存将导致系统特性难以确定。对此,通过虚拟导纳模型准确评估了系统的阻尼特性,发现其有源阻尼区域会随电网阻抗波动而变化,最大接近1/3采样频率;考虑LCL初始谐振频率处于不同的频率范围情况,利用开环极点及鲁棒性分析得到适用于不同情况的统一稳定性约束条件,并对应提出了一套鲁棒控制参数设计方法,从而充分保证电网阻抗波动下并联有源电力滤波器的稳定运行。在一台380V、45A的实验样机上验证了所提理论及控制策略的有效性。

电力系统并联电容器无功补偿技术分析

电力系统中存在着大量的感性负荷,电路中总电流滞后电压一定相位角,引起功率因数偏低,存在设备容量得不到充分的利用,在设备容量选择时偏大,线路中计算电流偏大的现状。为解决上述问题,对电路中并联电容器无功补偿进行研究,主要分析影响功率因数的主要因素、无功补偿的原理,通过理论计算以及利用实例在Multisim中仿真的方法,对并联电容器无功补偿的原理给以充分说明,并给出电容器容量计算的方法,最终通过实例仿真加以验证。

220 kV变压器低压侧10 kV无功补偿装置电容器绝缘故障分析

电容器无功补偿对提高系统的电压稳定、降低输电线损及变电损耗起着重要的作用。针对某220kV变电站10kV系统发生的电容器外熔断器保护全部熔断及本体烧毁事故,基于故障电容器的解剖情况,分析了电容器绝缘损坏的主要原因以及故障进一步扩大的原因,计算分析发现电容器不平衡保护整定值不合理性,并通过仿真软件PSCAD/EMTDC复现故障过程,验证故障结果,最后为避免故障再次发生提出了相应的处理建议,保证电容器的正常运行。

基于滤波的电力计量系统分流窃电行为动态识别方法

以准确识别电力计量系统分流窃电行为为目标,提出基于滤波的电力计量系统分流窃电行为动态识别方法。将去噪后的用电负荷数据作为基于模糊C均值聚类的用电负荷数据分类方法的分类目标,按照电压、电流等不同数据属性实现负荷数据分类;使用基于负荷数据局部异常因子的窃电行为检测方法,根据负荷数据点的邻域点密度阈值,判断电力计量系统在空间维度、时间维度是否存在分流窃电行为,并预估窃电量。实验结果显示:所提方法对某电力计量系统分流窃电行为动态识别精度较高,识别结果与实际相符。

旁路不停电作业分流异常的分析

随着企业和居民用户对供电可靠性需求提升,配网不停电作业已逐渐替换传统计划停电作业成为配电网线路设备主流检修手段。通过旁路作业法带负荷更换或安装开关、跌落式熔断器等设备是配网不停电作业常规复杂作业项目,电网企业各基层单位广泛开展该项作业。文章针对现场实际作业中发现的旁路系统分流异常问题开展分析,提出此类作业须注意问题和应采取措施,保障旁路作业安全有序开展。

UPS电控系统在降低海上平台电力关断风险中的应用

阐述钻采平台UPS系统的故障原因,通过对UPS系统馈线柜开关保护方式的优化升级,将欠压脱扣优化为分励脱扣,并对UPS电控系统、镍铬蓄电池备用电源系统优化,从而解决设计缺陷。

10 kV成套并联电容器无功补偿柜故障分析

针对某变电站一例10 kV成套并联电容器无功补偿柜柜内短路,引发10 kV系统短时电压波动的故障进行了分析,发现单相接地故障引发喷射式熔断器熔断,从而发展成三相短路,提出了相应的改造及防范措施。

出口德国内电混合动力调车机车燃油箱强度仿真研究

以出口德国内电混合动力调车机车燃油箱为研究对象,根据EN 12663-1:2010+A1:2014《铁路应用铁道机车车辆车体结构要求第1部分:机车和旅客列车(和货车的替代方法)》规定的运行工况分析燃油箱静强度和疲劳强度,根据VDI 2230-1:2015《高强度螺栓连接的系统计算单个圆柱螺栓连接》校核燃油箱安装螺栓强度,并进行燃油箱模态分析。结果表明,燃油箱能够满足德国内电混合动力调车机车的设计要求。