Optimal Configuration Method for Multi-Type Reactive Power Compensation Devices in Regional Power Grid with High Proportion of Wind Power

As the large-scale development of wind farms(WFs)progresses,the connection ofWFs to the regional power grid is evolving from the conventional receiving power grid to the sending power grid with a high proportion of wind power(WP).Due to the randomness of WP output,higher requirements are put forward for the voltage stability of each node of the regional power grid,and various reactive power compensation devices(RPCDs)need to be rationally configured to meet the stable operation requirements of the system.This paper proposes an optimal configuration method for multi-type RPCDs in regional power grids with a high proportion of WP.The RPCDs are located according to the proposed static voltage stability index(VSI)and dynamicVSI based on dynamic voltage drop area,and the optimal configuration model of RPCDs is constructed with the lowest construction cost as the objective function to determine the installed capacity of various RPCDs.Finally,the corresponding regional power grid model for intensive access to WFs is constructed on the simulation platform to verify the effectiveness of the proposed method.

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.

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.

Steady-state Voltage Reactive Compensation Method for Half-wavelength Transmission Lines Considering Equivalent Power Supply Impedance

Half-wavelength AC transmission(HWACT)refers to transmission along lines with an electrical distance of half the power frequency wavelength.The voltage amplitude at the sending terminal is equal to that at the receiving terminal in steady-state.Furthermore,the voltage at the receiving terminal does not vary with load.However,the electrical distance has been extended in actual HWACT lines because of the impact of the equivalent power supply impedance,so the attractive characteristics no longer hold.As a result,reactive power compensation methods with constant power factor and constant voltage are needed and these are presented in this paper.The steady-state operational characteristics,the calculation methods of additional reactive power compensation and the admittance of a controllable shunt reactor are also given.The methods proposed in this paper are relatively simple to implement,and the calculations involved are straightforward,resulting in effective voltage stabilization.The results indicate that such compensation methods can increase the transmission capacity while maintaining a relatively low voltage along the line.

Improved Hybrid Reactive Power Compensation System Based on FC and STATCOM and Its Control Method

The purpose of this study is to solve the main problems in distribution networks,including increased line loss and reduced power supply quality caused by insufficient capacitive reactive power.To reduce the capacity,voltage,and current stress of an active module of a compensation device and improve the cost performance of the device,an improved hybrid reactive power compensation system based on a fixed capacitor(FC)and a static synchronous compensator(STATCOM)is proposed.The topological structure and basic operating principle of the proposed reactive power compensation system are introduced.In addition,from the perspectives of output voltage,current,power,loss of the active part,and system compensation cost,the performances of the proposed reactive compensator and the inductively coupled STATCOM(L-STATCOM)are compared and analyzed.Furthermore,the key parameters of the proposed system are designed,and the joint optimization control strategy of the FC and STATCOM is studied.The correctness and effectiveness of the proposed topology structure and control method are verified by simulations.

基于背靠背变流器的牵引变电所群供电系统负序集中补偿方案

针对牵引变电所群供电系统导致的外部电源公共连接点处三相电压不平衡问题,提出了一种基于背靠背变流器的集中式有功型负序补偿方案。该方案的补偿装置可实现容量配置的最优解,且负序补偿的同时还可兼顾无功补偿。介绍了基于背靠背变流器的牵引变电所群供电系统拓扑结构;根据牵引变电所群供电系统及补偿装置间的功率关系分别阐述了该方案的负序、无功补偿原理,推导了补偿装置计算容量表达式,分析了补偿装置计算容量变化规律;为保证补偿装置快速、稳定运行,提出了适用于负序、无功补偿的双闭环控制策略;通过仿真证明所提方案的有效性和可行性。结果表明:所提方案对牵引变电所群供电系统具有良好的负序、无功补偿效果,且补偿装置容量配置实现了最优解,具有较强的经济性与应用潜力。

考虑柔性有载调压变压器的两阶段电压无功优化协调控制方法研究

随着配电网中分布式光伏(distributed photovoltaic,DPV)大量并网,电压越限和电压波动越来越严重,考虑新型电能质量治理装置的电压无功优化协调控制方法需要进一步完善,以适应电网的新变化。该文考虑了新型柔性有载调压变压器(on-load tap changer,OLTC)的电能质量调节作用,提出一种两阶段电压无功优化协调控制方法,其中一阶段为日前小时级调度阶段,根据分布式光伏和负荷的预测数据,通过潮流计算和迭代优化,获取DPV的有功出力结果、柔性OLTC分接头和电容器组的投切结果;二阶段为分钟级无功优化阶段,在第一阶段的基础上,考虑柔性OLTC和DPV的无功出力特性,调节装备无功出力的同时修正第一阶段电容器组投切组合,进一步降低各个节点最大电压偏差,使配电网电压分布更合理。搭建了IEEE33节点配电系统仿真模型,所提出的考虑柔性OLTC的两阶段电压无功优化协调控制方法能够在常规经济性最优目标下的88.07%DPV消纳水平基础上提高9.29%,同时满足全节点全时段电压偏差小于0.1pu,综合经济性提高7.8%,结果证明了所提方法的合理性和有效性。

基于DIgSILENT/PowerFactory的轻型直流输电系统建模和仿真

介绍了轻型直流输电系统的结构特点,建立了基于电力系统仿真软件DIgSILENT/PowerFactory的轻型直流输电系统模型,分析了基于同步d-q旋转坐标系下的电压源换流器的稳态数学模型和直流电压、有功功率和无功功率的控制策略,对系统在直流电压、有功功率及无功功率变化条件下的动态性能进行了仿真。仿真结果表明,该系统具有很好的动态响应能力和鲁棒性,可以稳定工作于2个电网之间,独立控制无功功率达到静态无功补偿的作用。