电流互感器取电电源的研究与设计

发布时间：2018-06-24 23:27

本文选题：电流互感器 + 输电线缆　；参考：《浙江大学》2015年硕士论文

【摘要】：随着电力工业和智能电网产业的发展,对高压输电线缆的运行状态进行实时监测交得至关重要,为此需要在输电线缆周围部署大量的监测设备。然而输电线缆分布广阔且很多位于野外或地下,其周围一般没有常规电源,因此需设计特殊的电源为这些监测设备供电。在各种特殊电源中,使用电流互感器将原边即输电线缆的电流感应到副边为监测设备供电的电源能够提供的功率最大；但由于输电线缆电流变化范围极为宽泛,这种电流互感器取电电源存在原边电流小时供能不足和原边电流大时输出电压失控的问题。针对这些问题,本文对电流互感器取电电源在以下三个方面进行了研究,并将研究结果应用到了取电电源的设计中：首先,针对原边电流小时取电功率不足的问题,采取在电流互感器副边并联匹配电容的措施,显著增大了它的取电功率；并在电流互感器的参数已知或可测量的前提下,对它能够从某一特定的低原边电流取得的最大功率以及取得最大功率时电流互感器的副边电压、匹配电容容值等进行了定量的分析和计算,以便合理设计取电电源的电气参数,使之在原边电流为这一特定值时取得最大功率,满足输电线缆监测设备的需要。其次,针对原边电流大时取电电源输出电压失控的问题,在电流互感器副边并联旁路开关,并在每个原边电流周期内将其闭合一段时间,以将电流互感器的副边短路,中断它向取电电源的供电。为简化取电电源的硬件电路设计,采用将旁路开关集成到桥臂中的整流电路实现上述功能,提出了这一整流电路的一种控制方法,并对该整流电路在这种控制方法下的工作过程做了详细分析。此外,对取电电源的整流电路使用其他结构和控制方法时的工作过程和电路特性也做了讨论。最后,针对原边电流比上述特定值更低时取电电源的输出功率不足,无法保证对输电线缆监测设备正常供电的问题,起用后备电池和取电电源一同向监测设备供电,并使取电电源输出最大的功率,以减少对后备电池的依赖。经过分析比较,选择了Buck-Boost或Flyback拓扑作为取电电源的后级DC-DC变换器,使得在原边电流波动时,后级DC-DC变换器输出最大功率所需的占空比几乎保持不变,简化了DC-DC变换器的设计。
[Abstract]:With the development of power industry and smart grid industry, it is very important to monitor the running state of HV transmission cable in real time, so it is necessary to deploy a large number of monitoring equipment around the transmission cable. However, transmission cables are widely distributed and many of them are located in the field or underground, and there is usually no conventional power supply around them. Therefore, special power supply is needed to supply these monitoring equipment. Among all kinds of special power sources, current transformer is used to induce the current of the original side, the transmission cable, to the power supply supplied to the monitoring equipment by the secondary edge. However, because of the wide range of current variation of the transmission cable, The current transformer power supply has the problems of insufficient energy supply at the primary side current and out of control output voltage when the primary current is large. Aiming at these problems, this paper studies the current transformer power supply in the following three aspects, and applies the research results to the design of the power supply. Taking the measure of matching capacitance in parallel at the side of the current transformer, the power of the current transformer is increased significantly, and the parameters of the current transformer are known or can be measured. The maximum power which can be obtained from a particular low primary current and the secondary voltage of the current transformer and the capacitance capacity of the current transformer are quantitatively analyzed and calculated in order to reasonably design the electrical parameters of the power supply. The maximum power is obtained when the original side current is this particular value, which meets the needs of transmission cable monitoring equipment. Secondly, aiming at the problem that the output voltage of the current source is out of control when the primary current is large, the bypass switch is paralleled at the secondary side of the current transformer, and it is closed for a period of time during each primary current cycle to short-circuit the secondary edge of the current transformer. Interrupt its power supply to the power supply. In order to simplify the design of the hardware circuit of the power supply, the rectifier circuit which integrates the by-pass switch into the bridge arm is used to realize the above function. A control method of the rectifier circuit is proposed. The working process of the rectifier circuit under this control method is analyzed in detail. In addition, the working process and circuit characteristics of rectifier circuit with other structures and control methods are also discussed. Finally, in view of the problem that the output power of the power supply is insufficient when the original current is lower than the above specific value, it is impossible to guarantee the normal power supply to the monitoring equipment of the transmission line cable, so the backup battery and the power source are used to supply the power to the monitoring equipment together. And make the power supply output maximum power to reduce the dependence on the backup battery. After analysis and comparison, the Buck-Boost or Flyback topology is selected as the back stage DC-DC converter, which makes the duty cycle of the maximum output power of the back-stage DC-DC converter almost unchanged when the primary current fluctuates, and simplifies the design of the DC-DC converter.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM452;TM46

【参考文献】