【摘要】：多饋入直流輸電換相失敗故障發(fā)生頻繁,研究電網(wǎng)換相直流輸電(Line-Commutated-Converter High Voltage Direct Current, LCC-HVDC)系統(tǒng)換相失敗和多饋入直流輸電耦合作用是解決多饋入直流輸電換相失敗故障的基礎(chǔ)研究?jī)?nèi)容,有必要對(duì)其進(jìn)行研究。 文章從換相失敗的故障機(jī)理及影響因素兩個(gè)方面對(duì)換相失敗進(jìn)行研究,以此為基礎(chǔ)提出了基于觸發(fā)角上限和快速提前觸發(fā)的換相失敗預(yù)防方法,該方法由基于觸發(fā)角上限的換相失敗預(yù)判方法和快速提前觸發(fā)換相失敗預(yù)防方法組成�；谟|發(fā)角上限預(yù)判方法的核心理論依據(jù)為觸發(fā)角上限的計(jì)算方法,該方法由換相電壓時(shí)間面積這一概念推導(dǎo)得出。提出快速提前觸發(fā)換相失敗預(yù)防方法的目的是為了提供一種簡(jiǎn)單可靠、迅速的預(yù)防指令,用以快速的提前觸發(fā)晶閘管,預(yù)防換相失敗。在PSCAD/EMTDC環(huán)境下仿真的結(jié)果表明該方法可以有效降低由單相故障引起換相失敗的概率。 為從穩(wěn)定運(yùn)行區(qū)間分析多饋入直流輸電耦合作用,引入了視在短路比增量這一穩(wěn)態(tài)指標(biāo),該指標(biāo)將直流子系統(tǒng)間的相互影響等效為對(duì)受端交流系統(tǒng)短路比的增量。隨后對(duì)視在短路比的計(jì)算方法進(jìn)行研究,分析了直流電流、直流子系統(tǒng)容量、電氣距離對(duì)視在短路比的影響,進(jìn)而分析了系統(tǒng)運(yùn)行特性隨這些影響因素變化的趨勢(shì)。進(jìn)行了PSCAD仿真,仿真結(jié)果表明了將視在短路比增量用于分析雙饋入直流輸電系統(tǒng)的正確性和有效性。 為從電壓穩(wěn)定性角度分析多饋入直流輸電耦合作用,提出無功潮流耦合作用分析方法,該方法通過無功潮流的變化分析了當(dāng)某子系統(tǒng)受到無功擾動(dòng)之后,各子系統(tǒng)電壓變化的機(jī)理。為定量分析多饋入直流輸電各子系統(tǒng)之間的無功潮流支撐作用,提出了無功潮流支撐系數(shù)這一穩(wěn)態(tài)指標(biāo),并推導(dǎo)了該指標(biāo)的表達(dá)式�；跓o功潮流耦合作用分析方法,推導(dǎo)了雙饋入系統(tǒng)中多饋入靜態(tài)電壓穩(wěn)定性的表達(dá)式。該表達(dá)式揭示了無功潮流支撐系數(shù)、多饋入交互作用因子與靜態(tài)電壓穩(wěn)定性之間的關(guān)系,結(jié)合表達(dá)式對(duì)無功潮流支撐系數(shù)的影響因素進(jìn)行分析。最后,在PSCAD環(huán)境下的雙饋入直流輸電模型中進(jìn)行仿真,驗(yàn)證理論推導(dǎo)的正確性。
[Abstract]:Commutation failure of multi-infeed DC transmission occurs frequently. The research of power grid commutation DC transmission (Line-Commutated-Converter High Voltage Direct Current,) LCC-HVDC) system commutation failure and multi-feed DC transmission coupling are the basic research contents to solve the commutation failure fault of multi-infeed HVDC transmission, so it is necessary to study them. In this paper, the commutation failure is studied from two aspects: the fault mechanism of commutation failure and the influencing factors. Based on this, a method of commutation failure prevention based on the upper limit of trigger angle and fast early trigger is proposed. This method is composed of two methods: commutation failure prediction method based on the upper limit of trigger angle and fast early trigger commutation failure prevention method. The calculation method of the upper limit of trigger angle is based on the core theory of the upper limit prediction method of trigger angle, which is derived from the concept of time area of commutation voltage. The purpose of this paper is to provide a simple, reliable and rapid preventive instruction to trigger the thyristor in advance and to prevent the commutation failure. The simulation results in PSCAD/EMTDC environment show that this method can effectively reduce the probability of commutation failure caused by single-phase fault. In order to analyze the coupling effect of multi-fed HVDC transmission from stable operation interval, a steady-state index, apparent short-circuit ratio increment, is introduced, which equates the interaction between DC subsystems to the increment of short-circuit ratio to the receiving AC system. The influence of DC current, DC subsystem capacity and electrical distance on the apparent short-circuit ratio is analyzed, and the variation trend of system operating characteristics with these influencing factors is analyzed. The PSCAD simulation results show that the apparent short-circuit ratio increment is correct and effective in the analysis of double-fed HVDC transmission systems. In order to analyze the coupling effect of multi-feed HVDC transmission from the angle of voltage stability, a reactive power flow coupling analysis method is proposed. The mechanism of voltage variation in each subsystem. In order to quantitatively analyze the support function of reactive power flow between subsystems of multi-fed HVDC transmission, the steady-state index of support coefficient of reactive power flow is proposed, and the expression of the index is derived. Based on the coupling analysis method of reactive power flow, the expression of multi-feed static voltage stability in double-feed system is derived. The expression reveals the relationship between reactive power flow support coefficient, multi-feed interaction factor and static voltage stability. Combined with the expression, the influence factors of reactive power flow support coefficient are analyzed. Finally, the simulation of double feed in DC transmission model under PSCAD environment is carried out to verify the correctness of the theoretical derivation.
【學(xué)位授予單位】：華北電力大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TM721.1

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本文編號(hào)：2412902