分布式静止同步串联补偿器的潮流控制技术研究开题报告

 2020-02-10 10:02
1.目的及意义(含国内外的研究现状分析)

1.论文(设计)选题的意义

在电力系统的运行上,长期存在的巡回功率潮流使系统容量相对减少,大系统的低频振荡也曾使系统耗费很大精力应付,而快速可控的电力电子装置正是消除巡回功率和低频振荡的有力手段。尤其21世纪,输电系统运行将承担着更大的来自环境和电力市场等方面的压力,由于土地征用困难和人们对高压电场的恐惧,目前修建新的输电线的阻力比以往大得多, 这就要求电力公司充分发挥已有输电线的潜力,使其运行趋近于稳定和热极限。而提高动态和暂态稳定的最有效手段是采用快速反应的可控电力电子装置。随着电力市场机制的逐步推进,巨大的发电量由发电公司先卖到市场,再转卖给用户,这就需要增大输送能力。功率输送的变化次数也要快速增加 ,系统的控制会更复杂;电力市场还要求系统经过特定的“合同途径”去控制功率流向,在互联电网中如果再使用传统的控制方法已经不能满足大幅度调节的要求。以电子控制器来加强可控性和增大电力传输能力的交流输电系统可适应现今电力系统的发展。而FACTS技术正是可解决此类问题的有效途径。

上述的压力产生了增大输送能力 、保持系统稳定 、优化系统运行等需求。针对上述压力和需求应运而生的FACTS从根本上改变了交流输电网过去基本只依靠机械型、慢速、间断及不精确的控制和优化技术措施的局面。FACTS装置为交流输电网提供了空前快速 、连续和精确的控制以及优化潮流功率的能力,同时可以确保系统稳定性,并有助于在事故时防止连锁反应造成的大停电结局。

但由于目前各种 FACTS 装置具有大功率、高电压、设计周期长、投资大及维护成本高等特点,限制了 FACTS 技术的广泛应用。针对这种情况,美国电力电子专家 Divan. D. M 教授提出了分布式柔性交流输电系统(Distributed FACTS,D-FACTS)概念,它可以较好地解决以上问题。D-FACT的核心是小额定容量(10kVA)的静止串行补偿器DSSC,DSSC 的一个重要部分是单匝变压器(SingIe Turn Transformer,STT),STT 使DSSC机械地夹在传输线上,传输线作为 STT 的次级绕组。DSSC 采用SSSC的控制方法,注入传输线一个与输电线电流呈合适相角的电压来改变输电线路的有效阻抗,控制线路潮流。

在此背景下,本课题研究分布式静止同步串联补偿器的潮流控制的关键技术。

In the operation of the powersystem, the long-standing power flow of the tour makes the system capacityrelatively reduced. The low-frequency oscillation of the large system alsomakes the system consume a lot of energy, and the fast and controllable powerelectronic device eliminates the tour power and low-frequency oscillation. apowerful means. Especially in the 21st century, transmission system operationwill bear greater pressure from the environment and electricity market,especially in developed countries, due to difficulties in land acquisition andpeople’s fear of high-voltage electric fields, the current resistance to buildnew transmission lines. Much larger than before, this requires power companiesto take full advantage of the potential of existing transmission lines to bringtheir operations closer to stability and thermal limits. The most effectivemeans of improving dynamic and transient stability is the use of fast-reactingcontrollable power electronics. With the gradual advancement of the powermarket mechanism, huge power generation is sold to the market by the powergeneration company and then resold to users, which requires an increase in thetransmission capacity. The number of changes in power transmission also needsto increase rapidly, and the control of the system will be more complicated.The power market also requires the system to control the power flow through aspecific “contract path”. If the traditional control method is used in theinterconnected power grid, it cannot meet the large Adjustment requirements. AnAC transmission system that uses electronic controllers to enhancecontrollability and increase power transmission capacity can adapt to thedevelopment of today's power systems. And FACTS technology is an effective wayto solve such problems.

The above pressures create the needto increase transport capacity, maintain system stability, and optimize systemoperation. FACTS, which has emerged from the above pressures and demands,fundamentally changed the situation that the AC transmission network relied onmechanical, slow, intermittent and inaccurate control and optimizationtechniques in the past. The FACTS unit provides unprecedented fast, continuousand precise control of the AC grid and the ability to optimize tidal powerwhile ensuring system stability and helping to prevent large outages caused bychain reactions in the event of an accident.

However, due to the high power, highvoltage, long design cycle, large investment and high maintenance cost ofvarious FACTS devices, the wide application of FACTS technology is limited. Inresponse to this situation, Professor Divan. D. M, a US power electronicsexpert, proposed the concept of distributed flexible AC transmission system(Distributed FACTS, D-FACTS), which can better solve the above problems. Thecore of D-FACT is the small serial capacity (10kVA) static serial compensatorDSSC. An important part of DSSC is the single-turn transformer (SingIe TurnTransformer, STT). STT mechanically clamps the DSSC on the transmission line.The transmission line acts as the STT. Secondary winding. The DSSC uses theSSSC control method to inject a voltage at the appropriate phase angle of thetransmission line to change the effective impedance of the transmission lineand control the line current.

In this context, this paper studiesthe key techniques of power flow control for distributed static synchronousseries compensators.

二. 分布式静止同步串联补偿器的相关研究

1.灵活柔性交流输电技术FACTS的起源

1.1FACTS定义

柔性交流输电技术,也称灵活交流输电技术,它是综合电力电子技术 、微处理和微电子技术 、通信技术而形成的用于控制交流输电的新技术。 FACTS概念是由美国著名电力专家 N. G. Hingorani于 1986年创建的。所谓 “柔性控制 ”,主要是区别和相对于原来交流电网中的常规 “刚性控制 ”而言。这不仅是由于前者主要依靠电子型技术,后者常是机械型或机电型技术,更重要的差别在于其控制作用的快速性、精确性 、连续性、柔韧性、有效性等。对于 FACTS的含义和界面一直众说纷纭,存在不少的争论,就连创建人自己的说法也一变再变 。N. G. Hingorani对 FACTS早期的定义是:FACTS就是基于晶闸管组件的控制器, 其中包括移相器、新型静止无功补偿器 、电气制动器 、串联电容调节器 、带负荷抽头调节器 、故障电流限制器以及其他一些尚未发明的控制器。

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