Research on Faint Ground Fault Detection in Power Distribution Line

在今天的配电网络中必须实现的是将电力供应的解释率降低到尽可能低的水平，如果可能的话为零。本研究提出了一种尝试，这样的要求，并针对提供一种技术，它可以是一种有效的手段，找出微弱的恶化在配电线路的绝缘状态。本文讨论了本实验室研制的磁场传感器的适用性，并讨论了提高探测灵敏度的几个基本问题：（1）对于低强度磁场的探测，改进了灵敏度与噪声的关系;在这一点上的一个试验是通过在三相零相电流检测进行;（ii）在传感器中使用的核心的选择的核心噪声占据了很大的重量出现在传感器输出中的噪声的问题被澄清。研制了其测量系统，给出了两种不同类型岩心的具体测量结果。在此基础上，提出了一种寻找适合传感器的磁芯的方法;（3）在传感器电路的构成上，提出了一种新型的基准电压产生电路。这有可能提高传感器电路的精度。这些是实现传感器的高检测灵敏度所需的技术。考虑到它们，必须执行传感器的重构。通过现场测试验证了该方法对60 Hz电力线磁噪声的降噪效果。

What has to be achieved in the today's power distribution network is to reduce the interpretation rate of power supply to as low a level as possible, if possible to zero. This study presents a trial for such a requirement and is directed to provide a technique which can be an effective means for finding out faint deterioration in the insulation state of the distribution line. The applicability of the magnetic field sensor which has been developed in our laboratory are discussed and some fundamental problems for improving the detection sensitivity are treated : (i) with respect to such the detection of low level magnetic field, the relationship between the sensitivity and the noise is refined. One trial on this point is performed through the zero phase current detection in three phase ; (ii) on the choice of the core utilized in the sensor the problem of core noise which occupies a large weight in the noise appearing in the sensor output is clarified. Its measurement system is developed and concrete measurement result is presented on two different types of core. Based on this system, we obtain a means for searching the core fit for the sensor ; (iii) on constitution of the sensor circuit a new type of reference voltage generating circuit is presented. This has a possibility of improving the precision of the sensor circuit. These are the technology required for achieving the high detection sensitivity of the sensor. Taking into account them, the reconstitution of the sensor has to be performed. After that the proposed approach will be put into practice by certifying the degree of noise reduction of 60Hz power line magnetic noise rough the field testing.