基于諧波阻抗測量技術的配電網(wǎng)三相自適應重合閘技術研究
發(fā)布時間：2019-04-19 05:52
【摘要】：目前國內(nèi)配電網(wǎng)中應用的傳統(tǒng)自動重合閘裝置在重合閘之前不自動判斷故障性質(zhì),不論故障性質(zhì)如何,進行盲目重合,當重合于帶永久性故障的線路時,不僅會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)自動重合閘重合失敗率升高,使得自動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)自適應重合閘技術有十分重要的意義。本文針對目前配電網(wǎng)自動重合閘技術存在的上述問題,提出了一種基于諧波阻抗測量技術的配電網(wǎng)三相自適應重合閘方法。對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,需要采用有源法對其施加激勵以獲得響應進而對其進行故障判定。本文所述方法的基本思想是當中壓配電線路因相間故障三相自動跳閘且故障點電弧去游離結束后,將一逆變電源通過一個晶閘管瞬時加在低壓線路上,基于產(chǎn)生的暫態(tài)電壓電流計算系統(tǒng)的諧波阻抗,進而判斷線路中是否還存在故障。利用系統(tǒng)測量點處諧波阻抗虛部與實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出了瞬時性故障和永久性故障下系統(tǒng)的諧波阻抗表達式,據(jù)此得出兩個理論判據(jù),經(jīng)過對比,最終選擇基于諧波阻抗虛部實部比值斜率的判據(jù)。仿真實驗及實驗室模擬實驗是檢驗理論有效性的重要實踐手段,對不同觸發(fā)角和不同故障電阻下的瞬時性故障和永久性故障進行實驗分析,驗證了該方法的有效性。線路上的電動機會對測量結果產(chǎn)生影響,計及帶不同類型負載的電動機停電后轉速下降情況和失電殘余電壓兩個影響因素,采用本文方法對電動機的諧波阻抗進行了理論分析和仿真實驗,證明本文所述方法對含電動機負載的配電系統(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.
【學位授予單位】：山東大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TM762.2
本文編號：2460657
[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.
【學位授予單位】：山東大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TM762.2
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，本文編號：2460657
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