發(fā)布時(shí)間：2019-04-19 05:52

【摘要】：目前國內(nèi)配電網(wǎng)中應(yīng)用的傳統(tǒng)自動(dòng)重合閘裝置在重合閘之前不自動(dòng)判斷故障性質(zhì),不論故障性質(zhì)如何,進(jìn)行盲目重合,當(dāng)重合于帶永久性故障的線路時(shí),不僅會(huì)使斷路器的工作條件惡劣,還給電力系統(tǒng)造成沖擊。特別是隨著國內(nèi)配電網(wǎng)的升級(jí)改造,電纜線路大量使用,既有架空線又有電纜線的混合線路大量涌現(xiàn),傳統(tǒng)自動(dòng)重合閘重合失敗率升高,使得自動(dòng)重合閘可以提高供電可靠性的優(yōu)勢無法充分發(fā)揮。因此研究一種在重合之前判斷配電線路上是否還有故障的配電網(wǎng)自適應(yīng)重合閘技術(shù)有十分重要的意義。本文針對(duì)目前配電網(wǎng)自動(dòng)重合閘技術(shù)存在的上述問題,提出了一種基于諧波阻抗測量技術(shù)的配電網(wǎng)三相自適應(yīng)重合閘方法。對(duì)于三相跳閘后完全失電狀態(tài)下的配電線路,由于其本身所含電壓電流信息量少,需要采用有源法對(duì)其施加激勵(lì)以獲得響應(yīng)進(jìn)而對(duì)其進(jìn)行故障判定。本文所述方法的基本思想是當(dāng)中壓配電線路因相間故障三相自動(dòng)跳閘且故障點(diǎn)電弧去游離結(jié)束后,將一逆變電源通過一個(gè)晶閘管瞬時(shí)加在低壓線路上,基于產(chǎn)生的暫態(tài)電壓電流計(jì)算系統(tǒng)的諧波阻抗,進(jìn)而判斷線路中是否還存在故障。利用系統(tǒng)測量點(diǎn)處諧波阻抗虛部與實(shí)部之比值斜率做判據(jù),據(jù)此判斷線路是否還帶有故障,進(jìn)而通過通訊方式通知饋線出口斷路器(或其它斷路器)是否進(jìn)行重合閘。通過靈活調(diào)節(jié)觸發(fā)角,可以靈活改變暫態(tài)電壓的峰值,既不會(huì)給線路帶來過大的沖擊,又可以發(fā)現(xiàn)線路上的隱性故障。本文用理論分析推導(dǎo)出了瞬時(shí)性故障和永久性故障下系統(tǒng)的諧波阻抗表達(dá)式,據(jù)此得出兩個(gè)理論判據(jù),經(jīng)過對(duì)比,最終選擇基于諧波阻抗虛部實(shí)部比值斜率的判據(jù)。仿真實(shí)驗(yàn)及實(shí)驗(yàn)室模擬實(shí)驗(yàn)是檢驗(yàn)理論有效性的重要實(shí)踐手段,對(duì)不同觸發(fā)角和不同故障電阻下的瞬時(shí)性故障和永久性故障進(jìn)行實(shí)驗(yàn)分析,驗(yàn)證了該方法的有效性。線路上的電動(dòng)機(jī)會(huì)對(duì)測量結(jié)果產(chǎn)生影響,計(jì)及帶不同類型負(fù)載的電動(dòng)機(jī)停電后轉(zhuǎn)速下降情況和失電殘余電壓兩個(gè)影響因素,采用本文方法對(duì)電動(dòng)機(jī)的諧波阻抗進(jìn)行了理論分析和仿真實(shí)驗(yàn),證明本文所述方法對(duì)含電動(dòng)機(jī)負(fù)載的配電系統(tǒng)依然有效。該方法所依據(jù)的理論原理清晰,物理概念明確,為國內(nèi)配電網(wǎng)自適應(yīng)重合閘問題的解決提供了一種可行的方案。
[Abstract]:At present, the traditional automatic reclosing devices used in domestic distribution networks do not automatically judge the nature of faults before reclosing, regardless of the nature of the faults, blindly reclosing, when they are coincident with lines with permanent faults. It will not only make the working conditions of circuit breaker poor, but also impact the power system. Especially with the upgrading of the domestic distribution network, the cable lines are used in large numbers, the mixed lines with both empty and cable lines emerge in large numbers, and the failure rate of the traditional automatic reclosing and reclosing is increased. The advantages of automatic reclosing can improve the reliability of power supply can not be fully developed. Therefore, it is of great significance to study an adaptive reclosing technique for distribution network to determine whether there is any fault or not before coincident. In this paper, a three-phase adaptive reclosing method for distribution network based on harmonic impedance measurement is proposed to solve the problems mentioned above in the automatic reclosing technology of distribution network. For the distribution line under the condition of complete loss of electricity after three-phase tripping, it is necessary to use the active method to excite the distribution line in order to obtain the response and then judge the fault because it contains less information of voltage and current. The basic idea of the method described in this paper is that after the three-phase automatic tripping due to the phase-to-phase fault and the end of arc ionization at the fault point, a inverter power supply is temporarily added to the low-voltage line through a thyristor. The harmonic impedance of the system is calculated based on the generated transient voltage and current, and then the fault in the line is judged. The ratio slope of harmonic impedance imaginary part to real part at the measurement point of the system is used as a criterion to judge whether the line still has faults or not. Then the feeder outlet circuit breaker (or other circuit breaker) is notified by means of communication whether the circuit breaker (or other circuit breaker) is reclosing or not. By flexibly adjusting the trigger angle, the peak value of transient voltage can be changed flexibly, which will not bring too much impact on the line, but also can find the hidden fault on the line. In this paper, the expressions of harmonic impedance of the system under transient fault and permanent fault are derived by theoretical analysis, and two theoretical criteria are obtained. After comparison, the criterion based on the ratio slope of the real part of the imaginary part of harmonic impedance is selected. Simulation experiment and laboratory simulation experiment are important practical means to verify the theoretical validity. The experimental analysis of transient faults and permanent faults under different trigger angles and different fault resistors proves the effectiveness of the proposed method. The motor on the line has an effect on the measurement results, taking into account the two factors that affect the motor speed drop after the power outage with different types of loads and the residual voltage of loss of electricity. In this paper, the harmonic impedance of the motor is analyzed theoretically and simulated. It is proved that the proposed method is still effective for the distribution system with motor load. The theoretical principle and physical concept of this method are clear, which provides a feasible scheme for solving the problem of adaptive reclosing in domestic distribution network.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TM762.2

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本文編號(hào)：2460657