住宅负荷特性及其应用研究

发布时间：2018-07-12 11:33

本文选题：住宅负荷 + 计算负荷　；参考：《重庆大学》2014年硕士论文

【摘要】：随着人们生活水平的提高，家用电器使用数量和种类不断增加，导致目前住宅负荷用电特性有了很大改变，对住宅计算的负荷估计出现较大偏差，这些新型用电设备多为单相非线性负荷，使得配电系统中谐波问题越来越严重，因此需要对此开展全面系统的研究。论文通过实测数据对住宅负荷的用电特性进行分析。给出了低压配电系统不同配电点的日负荷曲线，并针对负荷曲线的特征参数以及目前住宅供电变压器负荷率普遍偏低的问题进行了分析。通过对大量单户负载的实验数据分析得到其在每半小时的功率分布情况，采用核密度估计方法对每个时间段的数据做拟合，提出通过随机抽样建立与住宅户数对应的日负荷曲线，并进行需要系数确定的方法。该方法可有效利用自动抄表系统数据，及时更新负荷计算所需的基本计算参数——需要系数，从而避免负荷计算结果与实际使用结果偏差较大的问题。单相非线性性质的用电设备大量使用，导致在低压配电系统中含有很多的高次谐波电流，尤其是3次谐波电流含量较大，谐波问题已经是配电系统中不可忽视的问题。为了知道住宅负荷的配电系统中具体的谐波情况，在本文中对某住宅小区不同位置的配电线路上谐波电流进行了分析，依据实验数据，分别对一天内和一年中的电流谐波特性进行了对比分析，另外对某办公室进线上的电流谐波特性进行了分析。本文工作为低压配电系统中的谐波评估、谐波治理奠定了基础。 3次谐波电流含量较大是目前低压配电系统负荷的普遍特征，利用这一特征，对中性线断线故障检测方法方法进行了研究。其基本原理是通过检测线路首端三次谐波变化来判断是否发生中性线断线故障。仿真和实测分析表明：无论故障点以后的负荷是否平衡，当中性线断线时线路首端三次谐波均会呈现不同程度变化，故障点越接近线路首端，故障导致的三次谐波变化就越显著。本文对中性线断线故障时线路首端三次谐波和基波的突变规律，以及正常运行时，负荷三次谐波和基波的波动规律进行了研究和分析，，获得了将故障和正常运行状态进行有效区分的故障判据和故障判别流程。利用实测负荷的波动数据进行仿真研究，验证了故障检测判据在负荷平衡和不平衡状态下对中性线断线故障判别的有效性。
[Abstract]:With the improvement of people's living standard, the quantity and variety of household appliances are increasing, which leads to great changes in the characteristics of residential load, and there is a great deviation in the calculation of residential load. Most of these new electrical equipment are single phase nonlinear load, which makes the harmonic problem more and more serious in the distribution system, so it is necessary to carry out a comprehensive and systematic study. Based on the measured data, the paper analyzes the electrical characteristics of residential load. The daily load curve of different distribution points in low voltage distribution system is given. The characteristic parameters of load curve and the problem that the load rate of residential power supply transformer is generally low at present is analyzed. By analyzing the experimental data of a large number of single-family loads, the power distribution in every half hour is obtained, and the data of each time period is fitted by the kernel density estimation method. The daily load curve corresponding to the number of residential units is established by random sampling and the method of determining the demand coefficient is put forward. This method can effectively utilize the data of automatic meter reading system, and update the basic calculation parameter-the required coefficient of load calculation in time, so as to avoid the problem that the result of load calculation deviates greatly from the result of actual use. The large use of single-phase nonlinear power equipment leads to a lot of high-order harmonic currents in the low-voltage distribution system, especially the large content of the third harmonic current. The harmonic problem has become a problem that can not be ignored in the distribution system. In order to know the specific harmonics in the distribution system of residential load, the harmonic current on the distribution line of different positions in a residential district is analyzed in this paper, and according to the experimental data, The current harmonic characteristics in one day and one year are compared and analyzed respectively. In addition, the current harmonic characteristics on the incoming line of an office are analyzed. This paper lays a foundation for harmonic evaluation and harmonic control in low voltage distribution system. The high third harmonic current content is the universal characteristic of the load of low voltage distribution system at present. The fault detection method of neutral line break is studied. The basic principle is to detect the change of the third harmonic at the first end of the line to determine whether the breakage of neutral line occurs. Simulation and measured analysis show that the third harmonics of the first end of the line will change in varying degrees, regardless of whether the load after the fault point is balanced or not, the closer the fault point is to the first end of the line, the more close the fault point is to the first end of the line. The more significant the third harmonic change caused by the fault. In this paper, the sudden changes of the first and third harmonic and fundamental wave of the line when the neutral line is broken, and the fluctuation law of the third harmonic and the fundamental wave of the load in normal operation are studied and analyzed. A fault criterion and a fault identification flow are obtained to distinguish the fault from the normal operation state. By using the measured load fluctuation data, the validity of the fault detection criterion for the fault diagnosis of neutral line breakage is verified under load balance and unbalance.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM714

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