Reactive Power Compensation and Harmonic Suppression for Power Supply System of HT-7U Superconductive Tokamak

In this paper, a strategy for the reactive power compensation and harmonic suppression of the power supply system in HT-7U superconductive Tokamak is proposed. The optimized approach is given in the parameters design for passive filter. Also a controlling method with fast response time and good accuracy is put forward for the compensator, which is more suitable for the dynamic load.

Analysis on the Application of Reactive Power Compensation Technology in Electrical Automation

This paper introduces in detail the reactive power compensation technology and its characteristics, to reduce the loss of reactive power compensation technology 1N power distribution system and the electrical automation, improve the utilization rate, and realize the control of the voltage amplitude in the system network, voltage stability of power distribution system, has carried on the system analysis to reduce failure of the harmonic current to the power supply system and other functions. And the paper in-depth study on the application of reactive power compensation technology in electrical automation from the reactive compensation technology, substation and distribution line reactive power compensation, power users of reactive power compensation and other aspects.

Design to conditioning circuits of dynamic compensation of reactive power in the intelligence voltage controller

The paper introduces one design idea that making use of SCM to control Real-timely the dynamic compensation of reactive power.Firstly,design one Circuit to Sample the voltage and current,and by these datas we can easily calculate the power factor,and Voltage controller in the microcontroller to determine whether input the compensation capacitance according to the size of power factor,the paper also analyzes the principle of capacitance compensation and calculation method. Dynamic compensation for the entire process is quick and accurate.

Microcontroller Control of Reactive Power Compensation for Growing Industrial Loads

Many industrial installations in developing countries start-up as small factories, without regard for the need of compensation of reactive power, leading to significant financial losses in the long term. By improving the power factor, the customer can reduce its power demand and potentially increase efficiency of their equipment. A PIC microcontroller is used to switch capacitor banks to compensate for the reactive power. In order to determine the size of the capacitor bank needed, the microcontroller calculates the phase difference between the voltage and the current. The results obtained based on the lagging power factor for three test loads show an improvement in the power factor from 0.52 to 0.96 under different test load conditions.

Fuzzy Decision Method Applied in Action of Reactive Power Compensation Devices in Wind System

Frequent occurrence of large-scale cascading trip-off of wind turbine raises the concern about the decision process of ordered control of reactive power compensation devices. The theory of fuzzy multi-attribute decision making is adopted to ascertain the action sequence of reactive power compensation devices. First, a set of evaluation indexes including control sensitivity, regulation margin, response time, response level and cost is set up, and fuzziness of the proposed qualitative indexes is introduced to make them comparable to the proposed quantitative indexes. Then a method to calculate fuzzy weight of each index is put forward for evaluating relative importance of the proposed indexes. Finally, the action sequence of reactive power compensation devices is determined through the theory of fuzzy compromise decision making. The case study shows that the proposed method is effective to obtain the action sequence of reactive power compensation device which correspond to experience.

The design and simulation of TCR(thyristor control reactor) reactive power compensation system based on Arene

Inevitably, the question of reactive power compensation was aroused by applied of power electronics. Based on the study of the instantaneous reactive power theory, the designs of TCR(thyristor control reactor) thyristor control reactor reac- tive power compensation system and TCR single closed loop strategy was pro- posed. In addition, as digital simulation software, Arene was applied to simulate the Jining coal mine No.2 system. The simulation results validate that the design is effective to improve power factor and stabilization of the system.

Optimal Reactive Power Compensation of Distribution Network to Prevent Reactive Power Reverse

The capacitive reactive power reversal in the urban distribution grid is increasingly prominent at the period of light load in the last years.In severe cases,it will endanger the security and stability of power grid.This paper presents an optimal reactive power compensation method of distribution network to prevent reactive power reverse.Firstly,an integrated reactive power planning(RPP)model with power factor constraints is established.Capacitors and reactors are considered to be installed in the distribution system at the same time.The objective function is the cost minimization of compensation and real power loss with transformers and lines during the planning period.Nodal power factor limits and reactor capacity constraints are new constraints.Then,power factor sensitivity with respect to reactive power is derived.An improved genetic algorithm by power factor sensitivity is used to solve the model.The optimal locations and sizes of reactors and capacitors can avoid reactive power reversal and power factor exceeding the limit.Finally,the effectiveness of the model and algorithm is proven by a typical high-voltage distribution network.

Reactive Power in One-phase Circuits with Periodical Voltages - Reactive Power Compensation

The article states about reactive power compensation methods for circuits with non-sinusoidal voltages. An basic introduction to reactive power theory has been given, together with the optimal capacitance selection theory. There have been presented selected theories application in order to compensate the reactive power in one-phase circuits. The measurement results before the compensation have been discussed and measurement results after compensation of an actual object supplied from an non-sinusoidal voltage source were presented. The algorithms of optimal capacity selection were given, which connected in parallel to the circuit with inductive character will cause current root-mean-square value minimization. The measurement results after applying the reactive power minimization algorithm have shown improvement in compensation of strongly nonlinear receivers supplied with distorted signals.

Research on the Technology of Low Voltage Intelligent Reactive Compensation

In order to improve the power factor of the circuit, the article takes STM32 as core circuit to development reactive power compensation controller for low voltage intelligent reactive compensation. Circuit can detect electricity distribution network parameters, and send messages to mobile phone via SMS text messages by TC35 module, remote control compensation capacitor configuration parameters. Circuit with a flexible, reliable, convenient and practical features. This paper analyzes the structure of the controller hardware and software, and describes the hardware schematic circuit diagram and software diagram of the controller. Controller with integrated control, maximize the use of compensating equipment to improve grid power quality.

Reactive Power Problem and Solutions: An Overview

This article presents a comprehensive review for the dilemma of reactive power flow, while addressing different proposed remedy strategies: conventional and most update solutions. Robust analytical expressions were utilized to exploit the functionality of the proposed solutions and to show clearly the relation between the reactive power and control variables. The article, moreover, proposes a simple, innovative and robust analysis for static performance of the STATCOM. This approach shows clearly the advantages of the STA-TCOM in regulating reactive power and maintaining load voltage level within presumable limits. The approach, furthermore, reveals explicitly via analytical expressions the impact of the STATCOM operation on different aspects of the power system under concern.

Parameter Test and Analysis for Dynamic Compensation Devices in Wind Power Farms

The dynamic reactive power compensation equipment in Jiuquan Wind Power Base of above 10 GW consists of three different types of compensation devices, including： static var generator （SVG）, thyristor controlled compensator （TGR） and magnetically controlled reactor （MGR）. The lack of experimental verification of performance is not conducive to voltage/var management or full utilization of device capaci- ties. In order to solve the above problems, the compensation device performance test was performed. The test items and procedures were selected based on related national standards with the consideration for different grid structures and wind farm operation modes. The testing contents included dynamic regulating range, active power loss, dynamic response time, and harmonic voltage level. Three types of compensation devices installed in different wind farms, namely SVG, TCR and MCR, were chosen and tested. The performances were compared and analyzed according to the field test results.

Energy Efficiency of Reactive Dynamic Compensators

A parameter that allows an evaluation of power quality transmitted, or distributed, between energy source and the final user is electric system power factor. Among other aspects, a bigger power factor, close to unit value, relieves operational conditions of lines and cables, besides, it improves feeder＇s voltage behavior. Due to load variation along the day, the dynamic compensation of power factor allows maintaining this parameter close to the ideal. This paper brings a study about a reactive dynamic compensator based on the voltage control in a capacitive element, varying the reactive energy in accordance with the system demand, everything from the energy efficiency point of view. In distribution systems, the losses due to this variable compensation can be lower than in other compensation methods and also the voltage presents a better behavior, justifying its application.

The Actuality and Development Trend of Var Compensation for Distribution System

Effective reactive power compensation is very important to the safe,economical and high quality running of power system.The principle and characteristic of several main reactive power compensation devices were analyzed and compared in details, and the development trend and application prospect were viewed.

Allocation and sizing of reactive power compensators considering PV power and load demand uncertainty using beetle-antenna grey wolf optimization

Distributed photovoltaic(PV)systems play an important role in supplying many recent microgrids.The absence of reactive power support for these small-scale PV plants increases total microgrid losses and voltage-instability threats.Reactive power compensations(RPCs)should be integrated to enhance both microgrid losses and voltage profiles.RPC planning is a non-linear,complicated problem.In this paper,a combined RPC allocation and sizing algorithm is proposed.The RPC-integrating buses are selected using a new adaptive approach of loss sensitivity analysis.In the sizing process,the uncertainties in PV power and load demand are modelled using proper probability density functions.Three simulation techniques for handling uncertainties are compared to define the accurate and fast accurate method as follows:Monte Carlo simulation(MCS),scenario tree construction and reduction method,and point estimation method(PEM).The load flow equations are solved using the forward-backward sweep method.RPCs are optimally sized using the beetle-antenna-based strategy with grey wolf optimization(BGWO)to overcome the local minima problem that appeared in the other pre-proposed methods.Results have been compared using particle swarm optimization and conventional GWO.The proposed model is verified using the IEEE 33 radial bus system.The expected power loss has been reduced by 22% and 31% using compensation of 26% and 44%,respectively.The results obtained prove that the BGWO optimal power flow and PEM to handle the uncertainty can significantly reduce the computation time with sufficient accuracy.Under the study conditions,PEM reduces the computation time to 4 minutes compared with 4 hours for MCS,with only a 3% error compared with MCS as an uncertainty benchmark method.

含电动汽车和光伏的配电网演化动态博弈调度策略

针对大规模电动汽车的无序充电行为可能导致电网出现的三相不平衡问题,基于演化动态博弈模型,提出一种考虑三相负荷平衡和光伏消纳的电动汽车充电调度策略。首先,基于电动汽车接入时段的主观性以及光伏出力和负荷的不确定性,引入游牧集群和定居集群之间的演化动态博弈方程;然后,考虑用户侧和电网侧双方利益关系,设计以最小化电动汽车充电费用、三相负荷不平衡度和无功需求为目标的调度优化模型;最后,通过对某商业区配电网算例进行仿真求解,对比分析三相有功曲线、三相无功曲线以及荷电状态曲线的变化趋势。算例结果表明,该调度策略可有效降低三相不平衡度,满足无功补偿的需求以及改善用户充电成本。

动态电压恢复器(DVR)在化工企业的应用

在化工企业正常生产周期当中,关键电气设备的可靠及平稳运行至关重要,关键机组的润滑系统通常采用低压电机作为动力传动设备,在电网因各种原因发生电压暂降时,经常出现由于接触器低电压释放而导致的润滑系统失效,进而影响关键机组的正常运行的问题。为保证装置长周期运行、实现“抗晃电”的目标,在电源与用电设备间串联动态电压恢复器(DVR)可有效防止上述问题产生,对大机组平稳运行起到了重要保护作用。现将介绍动态电压恢复器(DVR)的功能及其特点,仿真故障状态下的补偿波形,并举例分析DVR在石化企业的应用情况,最后对DVR在未来化工企业中的进一步发展趋势进行了展望。

无功补偿与储能集成系统中H桥级联型功率变换器相内SoC快速均衡

无功补偿与储能集成系统应用于风、光电站具有经济性,其中H桥级联型功率变换器具有低功率因数运行特点,提升其相内SoC均衡速度有助于提升电池安全和储能系统容量利用率。在调制约束下,考虑相内SoC均衡中电压无功分量的叠加,分析不同功率因数时功率单元的SoC均衡能力。基于分析,提出相内SoC的快速均衡方法,设计均衡控制电压有功分量叠加方法,充分利用功率单元的SoC均衡能力。基于各功率单元叠加的电压有功分量设计相应单元的无功分量叠加方法,提升功率单元的SoC均衡能力。仿真分析验证了相内SoC快速均衡控制的有效性。

基于分布式协同控制技术的分散式无功补偿技术方案研究

结合实际工程的应用实例从分散式无功补偿方案的提出、分布式协同吸收方案的理论、具体工程方案的设计进行简单的论述。结合线路开通后的实际运行工况,利用设置于正线的能量回馈吸收装置实现了分散式无功补偿,该方案可减少或完全取消设置于主变电所侧的SVG容量,充分开发和利用了能馈吸收装置的能力,节约了工程投资,实现了既定设计目标。

基于轨道交通供电系统双向变流装置分散补偿无功的技术与应用研究

在城市轨道交通建设中,一般采用在新建主变电所内设置无功补偿装置等方式进行无功补偿,受安装场地、环控通风及供电线路无功特点等影响,补偿装置前期安装容量不宜过大。本文结合大功率可控双向变流装置的系统特征和应用情况,对双向变流装置分散补偿无功的原理及控制策略进行了论述及研究。依据实际工程案例对轨道交通供电系统无功情况进行分析,同时对采用双向变流装置分散补偿无功的可行性以及其系统接入、容量选择等方面进行分析,现场测试数据表明双向变流装置能够分散补偿地铁供电系统中压网络产生的容性无功,可供同类线路设计参考。

Voltage sag compensation strategy for unified power quality conditioner with simultaneous reactive power injection

Unified power quality conditioner(UPQC)holds the capability of solving power quality problems,especially shows good performance in the voltage sag compensation. In this paper, a compensation strategy based on simultaneous reactive power injection for UPQC(namely UPQC-SRI) is proposed to address the issue of voltage sag. The proposed UPQC-SRI determines the injection angle of compensation voltage with consideration of optimal configuration of UPQC current-carrying.Moreover, the compensation strategy also considers the current-carrying limit of UPQC, and then the zero active power injection region of UPQC-SRI(also called UPQCSRI region) is obtained. Under the conditions which exceed the UPQC-SRI region, the limit value of shunt current is determined by this proposed strategy. Finally, the proposed strategy and the corresponding algorithm are verified under the PSCAD/EMTDC platform. The result indicates the proposed UPQC-SRI strategy in this paper can provide more persistent voltage sag compensation than the previous strategies for the sensitive load.