基于谐波阻抗测量技术的配电网三相自适应重合闸技术研究
发布时间：2019-04-19 05:52
【摘要】：目前国内配电网中应用的传统自动重合闸装置在重合闸之前不自动判断故障性质,不论故障性质如何,进行盲目重合,当重合于带永久性故障的线路时,不仅会使断路器的工作条件恶劣,还给电力系统造成冲击。特别是随着国内配电网的升级改造,电缆线路大量使用,既有架空线又有电缆线的混合线路大量涌现,传统自动重合闸重合失败率升高,使得自动重合闸可以提高供电可靠性的优势无法充分发挥。因此研究一种在重合之前判断配电线路上是否还有故障的配电网自适应重合闸技术有十分重要的意义。本文针对目前配电网自动重合闸技术存在的上述问题,提出了一种基于谐波阻抗测量技术的配电网三相自适应重合闸方法。对于三相跳闸后完全失电状态下的配电线路,由于其本身所含电压电流信息量少,需要采用有源法对其施加激励以获得响应进而对其进行故障判定。本文所述方法的基本思想是当中压配电线路因相间故障三相自动跳闸且故障点电弧去游离结束后,将一逆变电源通过一个晶闸管瞬时加在低压线路上,基于产生的暂态电压电流计算系统的谐波阻抗,进而判断线路中是否还存在故障。利用系统测量点处谐波阻抗虚部与实部之比值斜率做判据,据此判断线路是否还带有故障,进而通过通讯方式通知馈线出口断路器(或其它断路器)是否进行重合闸。通过灵活调节触发角,可以灵活改变暂态电压的峰值,既不会给线路带来过大的冲击,又可以发现线路上的隐性故障。本文用理论分析推导出了瞬时性故障和永久性故障下系统的谐波阻抗表达式,据此得出两个理论判据,经过对比,最终选择基于谐波阻抗虚部实部比值斜率的判据。仿真实验及实验室模拟实验是检验理论有效性的重要实践手段,对不同触发角和不同故障电阻下的瞬时性故障和永久性故障进行实验分析,验证了该方法的有效性。线路上的电动机会对测量结果产生影响,计及带不同类型负载的电动机停电后转速下降情况和失电残余电压两个影响因素,采用本文方法对电动机的谐波阻抗进行了理论分析和仿真实验,证明本文所述方法对含电动机负载的配电系统依然有效。该方法所依据的理论原理清晰,物理概念明确,为国内配电网自适应重合闸问题的解决提供了一种可行的方案。
[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.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM762.2
本文编号：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.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM762.2
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