一种新型基于电流控制的静止无功发生器

一种新型基于电流控制的静止无功发生器

季　方,陈乔夫,张　宇,李新华,田　军(华中科技大学电气与电子工程学院,武汉430074)

摘　要:为了研究新型的静止无功发生器,用电路理论中的替代定理,提出了一种基于电流控制的静止无功发生

器(ASV G )的原理。该ASV G 由一个二次侧“多绕组”变压器和IG B T 逆变器构成,把变压器一次侧并联接入电网中,二次侧的每个绕组与一个IG B T 逆变器连接,通过控制变压器二次侧电流和一次侧电压的相位差,使整个变压器对于电网等效成纯电抗或纯电容负载。理论分析了这种原理,并与现有ASV G 比较后给出了一种具体实现方法。样机试验验证了基于电流控制的新型静止无功发生器原理的正确性及相对与传统静止无功发生器控制简单,谐波小的优点。

关键词:静止无功发生器;电流控制;变压器;多绕组;IG B T ;灵活交流输电系统中图分类号:TM43文献标志码:A 文章编号:100326520(2008)0521005205

基金资助项目:国家自然科学基金(50477047)。

Project Supported by National Natural Science Foundation of China (50477047).

Novel Advanced Static V ar G enerator with Current Control

J I Fang ,C H EN Qiao 2f u ,ZHAN G Yu ,L I Xin 2hua ,TIAN J un

(School of Electrical and Elect ronic Engineering ,Huazhong University of Science

and Technology ,Wuhan 430074,China )

Abstract :A novel Advanced Static Var Generator (ASV G )based on current control is proposed in terms of the Sub 2stitution Theorem in circuit theory.Firstly ,the principle of the novel Advanced Static Var Generator (ASV G )is analyzed.In the novel ASV G ,a transformer with one primary winding and multiple secondary windings is chosen and its primary winding is shunted with load while the multiple secondary windings are connected with multiple IG 2B T inventers.When the phase error between the current of secondary windings and voltage of primary winding sat 2isfies a certain relation ,the transformer exhibits an equivalent inductive or capacitive component for power system ,so that the conclusion could be drawn ,which instruct the Research on a Novel Advanced Static Var G enerator (AS 2V G )Based on Current Control.Secondly ,during the realization novel Advanced Static Var G enerator (ASV G ),several key technical problems are analyzed.As to the current detection ,the existing methods are illustrated.Con 2sidering all the methods mentioned ,the method based on the instantaneous reactive power is adopted.As to the problem of adaptability for the high voltage and large capacity ,several popular approaches are addressed.Among them ,the multiple windings topology is applied.As to the control algorithms and tactics ,the Triangle Wave Com 2parison PWM (Pulse Width Modulation )current control method is adopted ,it is all digital control system.Finally ,the validity of the novel ASV G is verified by the experimental results ,as well as the advantages compared to the more conventional ,such as simple control tactics and low harmonic component.K ey w ords :ASV G;current control ;transformer ;multiple windings ;IG B T ;FACTS

0　引　言

先进的静止无功发生器(ASV G )在国际会议上也被建议称为STA TCOM (Static Synchronous Compensator ),是灵活交流输电系统(FACTS )的一个重要的组成部分。作为新一代的并联型无功补偿装置,它具有传统固定容量的电容器及静止无功补偿装置(SVC )等无功补偿装置无法比拟的优点[1]。

从ASV G 装置研究现状来看,1994年清华大学与河南电力局联合开发的±20MVA 的ASV G

装置于2000年在河南投入运行[2,3];2005年,清华大学又与上海电网公司合作研制了50MVA 的STA TCOM [4,5]。在国外,自1980年日本三菱公司和关西电力推出的世界上第一台采用晶闸管强迫换流的20MVA SV G 并网运行以来,世界各大电力公司都竞相研究并力图抢占这一发展领域。到目前为止,除中国外有日本(Toshiba ,Mit subishi 公司),美国(西屋电气),德国(Siemens 公司),瑞典(ABB 公司),英国(Alstom 公司)和韩国(韩国电力研究院)等均有ASV G 装置投入运行[6]。

但是以上提到的ASV G 装置应用的原理无一例外均是将方波电压通过叠加,构造出近似的正弦波电压源再通过连接电抗器接到电网[6],区别只在于叠加的方式不尽相同。具体有:①二极管或电容

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5001・ 第34卷第5期

2008年 5月

高　电　压　技　术

High Voltage Engineering

Vol.34No.5

May 2008