440 / 2017-04-28 18:15:46

Research on the Temperature Real-time Monitoring Technology of High Voltage Disconnectors

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With the continuous development of electric power industry and the construction of smart gridin China, there is a growing demand for intelligent electrical equipment and its operational reliability.As the class switchgear equipment, disconnector has the largest amount of usage in electrical power system. Operating in a state of high voltage and heavy current, the operational reliability and the rise ofcontact temperature are closely related. In the course of power grid operation, the contact of open type disconnectoris influenced largely by external environment. The safe and stable operation of the power grid is seriouslyaffected by the overheat of contact, which caused by reasons such as unclean contact surface, oxidation of contact, electric shock, mechanical deformation and looseness, unfulfillment of closing, overload etc. These reasons can lead to the deteriorating condition of the contact, which even result in occasional power outage.It is displayed that the heating problems account for more than 60% among all faults and defects of disconnector. Therefore, measurement for the temperature of contact must be carried out to prevent overheat faults.The temperature real-time monitoring technology withlowcost and high efficiency is researched in this paper. Defects of abnormal heating are discovered in time, which is of great significance for ensuring the safe operation and improving power distribution reliability.
At the moment, the common temperature measurement method mainly contains infrared temperature measurement, fiber temperature measurement, sensor temperature measurement etc.Infrared temperature measure technology equipped with infrared imager is mainly applied in power line patrol. However, the application of infrared imager is restrictedto a great extent due to the limited infrared penetration and short communication distance.In the technology of fiber temperature measurement, the fiber optic isintertwined on the surface of moving button contact or fixed feeler lever of the disconnecting switch.Moreover, temperature data of high voltage switchcontact is transmitted to the monitoring center through fiber optic signal.Potential safety hazard exists in outdoor high voltage disconnecting switch as this technology is implemented by means of wire communication. The temperature of high voltage contact is detected by temperature sensor in the sensor temperature measurement technology in which the thermocouple, thermal resistance and semiconductor temperature sensor are its major temperature monitoring methods. Traditional thermocouple or thermistor temperature measurement method has mature technology whose performance is reliable. However, problems such asthe passivity and wireless communication anti-jamming ability remain to be solved.
The temperature distribution of disconnector contact is analyzed in this paper under different influential factors by means of numerical simulation calculation of temperature field and temperature rise test.Contact materials of various kinds, loop resistance in defect situation as well as the corresponding relation between loop resistance and contact temperature are designed in this paper.The online temperature measurement technology combined with the structure and principle of disconnector is analyzed and verified in this paper based on power supplied by the inductive current and wireless communication technique, solving problems in the online temperature measure system such as wireless data transmission, sensor operating supply and equipment high reliabilityin an environment of high voltage and strong electromagnetic.