配电电缆状态监测技术研究

发布时间：2018-10-30 12:55

【摘要】：随着城市电网电缆化率的不断提高，电缆故障已成为影响供电可靠性的重要因素，并呈现上升趋势。配电电缆隐蔽缺陷是其发生故障的前奏，而配电电缆缺陷通常表现为绝缘损坏，局部放电和温度异常是绝缘损坏的常见征兆和表象，二者既相对独立有具有一定的联系，局部放电会导致线芯及绝缘层温度异常；长期温度异常也会绝缘老化而发生诱发局部放电。由于电缆多敷设与地下，通过传统的巡视难以发现其局部放电及过热的隐蔽缺陷，从而导致电缆故障率居高不下。现有的检测电缆绝缘的方法多为耐压试验或者震荡波试验，但都需要停电，而且需要大量人力物力。对配电电缆进行状态监测的目的在于及时发现隐蔽缺陷，以便运行维护人员在缺陷处于萌芽状态时，就能够及早将其消除，从而避免停电等事故的发生。由于传统的巡视检查难以发现局部放电以及温度过高等隐蔽缺陷，致使缺陷逐步恶化，最终导致线路故障甚至同沟电缆起火等事故。状态监测可以通过先进的技术手段将这些隐蔽缺陷传送到后台，并发出警告信号，维护人员无需到达现场就可以掌握设备的运行状况，大大提高了缺陷处置效率，节省人力，降低故障率及运营成本。本文对配电电缆的状态监测技术做了很多研究，通过将交联聚乙烯电力电缆局部放电和温度异常的发生发展机理的研究，建立了与典型电缆绝缘缺陷类型对应的局部放电信号及温度特征库，并开发了基于计算机、集合多种识别算法的监测诊断系统。该诊断系统能通过采集局部放电信号及温度值进行缺陷辨别，能够实现在不停电状态下对电缆绝缘状态进行实时监测，可以避免绝缘检测造成的停电，减少人力物力成本。本文结合超高压电缆状态监测研究成果，从配电电缆局放监测和温度监测两个方面来阐述配电电缆在线监测技术中的研究成果，在局部放电信号特征分析、早期绝缘老化和温度监测技术创新的基础上，实现局部放电信号识别技术和温度监测相结合的技术突破。为公司搭建配电电缆状态监测系统提供了理论依据。
[Abstract]:With the continuous improvement of cable conversion rate in urban power network, cable faults have become an important factor affecting the reliability of power supply, and the trend is on the rise. The hidden defect of distribution cable is the prelude to its failure, while the defect of distribution cable is usually shown as insulation damage, partial discharge and temperature anomaly are common signs and appearances of insulation damage, both of which are relatively independent and have certain relationship. Partial discharge will lead to abnormal temperature of wire core and insulation layer. Long-term temperature anomalies will also cause insulation aging and induce partial discharge. Due to the cable laying and underground, it is difficult to find the hidden defects of partial discharge and overheating through the traditional inspection, which leads to the high failure rate of cable. Most of the existing methods for detecting cable insulation are voltage withstand test or shock wave test, but they all need power outages and a great deal of manpower and material resources. The purpose of monitoring the state of distribution cable is to find hidden defects in time, so that the operators can eliminate the defects as soon as they are in the bud, thus avoiding the occurrence of accidents such as power outages. Because it is difficult to find hidden defects such as partial discharge (PD) and excessive temperature in traditional inspection, the defects worsen gradually, and eventually lead to line failure or even accidents such as cable fire in the same ditch. State monitoring can transmit these hidden defects to the background by advanced technical means, and issue warning signals. Maintainers can master the operation status of the equipment without having to arrive at the scene, which greatly improves the efficiency of handling defects and saves manpower. Reduce failure rate and operating cost. In this paper, a lot of research has been done on the condition monitoring technology of distribution cable, and the mechanism of occurrence and development of partial discharge and temperature anomaly of XLPE power cable has been studied. The partial discharge signal and temperature signature database corresponding to typical cable insulation defect types are established and a monitoring and diagnosis system based on computer is developed. The diagnosis system can detect defects by collecting partial discharge signals and temperature values, and can realize real-time monitoring of cable insulation state without power failure. It can avoid blackout caused by insulation detection and reduce manpower and material cost. Combined with the research results of the condition monitoring of EHV cables, this paper expounds the research achievements in the on-line monitoring technology of distribution cables from two aspects of partial discharge monitoring and temperature monitoring, and analyzes the characteristics of partial discharge signals. Based on the innovation of early insulation aging and temperature monitoring technology, the technology breakthrough of partial discharge signal recognition and temperature monitoring is realized. It provides a theoretical basis for the company to build the distribution cable condition monitoring system.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM75

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