本文選題：周期性 + 惡劣天氣��； 參考：《長沙理工大學》2014年碩士論文

【摘要】：在電力系統(tǒng)的各種事故中,大停電是危害最為嚴重的一種。新世紀以來,研究人員先后發(fā)現(xiàn)世界各國大停電規(guī)模服從冪律分布而并非經(jīng)典可靠性理論假設的指數(shù)分布。研究表明,電力系統(tǒng)作為一個復雜系統(tǒng)具有自組織臨界性。大停電作為電力系統(tǒng)的動態(tài)行為,其規(guī)模服從冪律分布,并具有長程自相關性。在外界擾動和負荷增長的推動下,電力系統(tǒng)會不斷逼近自組織臨界態(tài)。臨界狀態(tài)下,外界擾動導致線路跳閘后,在潮流轉移作用下,可能引發(fā)連鎖過負荷和繼電保護系統(tǒng)的隱形故障,擴大事故范圍,造成大停電事故的冪律分布特性。電網(wǎng)大停電時,常伴隨有大量故障。研究表明,電網(wǎng)故障和大停電一樣具有冪律分布特性和長程自相關性。但電網(wǎng)故障對大停電的冪律分布特性有何種作用,未見報道；電網(wǎng)故障長程自相關性的形成機理,也缺乏相關研究。論文針對此類問題展開研究。為探明外界擾動所致電網(wǎng)故障對大停電冪律特性的影響,文章從北美大停電記錄數(shù)據(jù)和我國電網(wǎng)故障數(shù)據(jù)中找尋外界擾動獨立導致大停電冪律特性的證據(jù)。首先,抓住冪律分布和指數(shù)分布的差異,分析了造成北美大停電冪律特性厚尾部分的29條極值大停電記錄,發(fā)現(xiàn)其中有10起發(fā)生在惡劣天氣條件下且僅限于配網(wǎng)故障。因配電網(wǎng)為環(huán)網(wǎng)設計、開環(huán)運行,發(fā)生連鎖過負荷的概率遠小于輸電網(wǎng),該部分極值大停電可能為外界擾動獨立引起而并非連鎖故障作用；其次,還分析了國內(nèi)9處具有冪律分布特征的輸、配電網(wǎng)故障數(shù)據(jù)。分析江西數(shù)據(jù)表明,該省冰災期間負荷僅為正常情況下的一半,不會發(fā)生連鎖過負荷。此外,該省輸電網(wǎng)冰災期間線路跳閘146次,而確定為繼電保護誤動的僅有1次,同樣沒有明顯的連鎖故障。因江西電網(wǎng)冰災大停電系該省最大規(guī)模的停電事故,這從另一個角度證明了外界擾動可以在沒有連鎖故障的情況下引起大停電的冪律特性。為驗證電網(wǎng)故障長程自相關性由惡劣天氣引起的故障高峰所致,文章還分析了長沙和南昌電網(wǎng)故障數(shù)據(jù)。將故障數(shù)據(jù)按日極值故障數(shù)從高到低依次剔除最大日故障數(shù)據(jù),并利用趨勢波動法計算出各數(shù)據(jù)序列的Hurst指數(shù),發(fā)現(xiàn)Hurst值隨日故障最大值的減小呈下降趨勢,當日故障最大值降至10或9時,Hurst指數(shù)值甚至小于0.5。這意味著電網(wǎng)故障的長程自相關性主要是由惡劣天氣等外界擾動引起的故障高峰所致。
[Abstract]:Among all kinds of power system accidents, blackout is the most serious one.Since the new century, researchers have found that the power law distribution is not the exponential distribution of the classical reliability theory hypothesis.It is shown that the power system as a complex system has self-organizing criticality.As the dynamic behavior of power system, power outage is distributed according to power law and has long range autocorrelation.Driven by external disturbances and load growth, the power system will continue to approach the self-organized critical state.Under the critical condition, after the line tripping caused by the external disturbance, the cascading overload and the hidden fault of the relay protection system may be caused under the action of the power flow transfer, and the power law distribution characteristic of the blackout accident will be caused by enlarging the range of the accident.A large number of faults are often accompanied by power outages.It is shown that power law distribution and long range autocorrelation are similar to power outages.However, there is no report on the effect of power law distribution on power law distribution of power outages, and the formation mechanism of long range autocorrelation of power grid faults is also lack of relevant research.This paper focuses on this kind of problems.In order to find out the influence of power law characteristics caused by external disturbances on power law characteristics of power outages, this paper looks for evidence of power law characteristics caused by external disturbances from North American blackout record data and China power grid fault data.First of all, the difference between power law distribution and exponential distribution is grasped, and 29 extreme blackouts in the thick-tailed part of power law characteristic of power outages in North America are analyzed. It is found that 10 of them occur in severe weather conditions and are limited to distribution network failures.Because the distribution network is designed for loop network, the probability of occurrence of cascading overload is much smaller than that of transmission network. This part of extreme blackout may be caused by external disturbance but not cascading fault. Secondly,The fault data of power law distribution network in 9 places in China are also analyzed.The analysis of Jiangxi data shows that the load during ice disaster in this province is only half of that under normal conditions and there will be no interlocking overload.In addition, 146 trip trips were made during the ice disaster period of the provincial transmission network, but only one time was identified as relay protection maloperation, and there was also no obvious cascading fault.Since the ice disaster blackout in Jiangxi power grid is the largest power outage in the province, it is proved from another angle that the power law characteristic of the outage can be caused by external disturbance without cascading faults.In order to verify the fault peak caused by bad weather, the fault data of Changsha and Nanchang power networks are analyzed.The maximum daily fault data are eliminated according to the daily maximum number of faults from high to low, and the Hurst exponent of each data sequence is calculated by using trend fluctuation method. It is found that the Hurst value decreases with the decrease of daily maximum fault number.The maximum value of Hurst exponent is even less than 0.5.This means that the long range autocorrelation of power grid faults is mainly caused by the peak of faults caused by external disturbances such as bad weather.
【學位授予單位】：長沙理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TM732

【共引文獻】

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本文編號：1741276