Transmission line cable temperature monitoring device
Technical Field
The invention relates to a power transmission line cable temperature monitoring device used in the field of power online monitoring.
Background
Among the various existing grid faults, a line fault should constitute a central grid fault. From the current state of the art, line faults as a whole exhibit a frequency and a diverse characterization, including diverse fault sources. Wherein, because the cable insulation is ageing or the obstacle appears in the circuit and leads to the local resistance increase of cable, the temperature rise will lead to the cable to take place incident such as fire. Especially, due to the complexity of the transmission line, the conventional temperature monitoring means is difficult to realize, and if long-term online temperature monitoring and early warning are carried out on the transmission line, the overall stability and safety of a power grid can be threatened.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a power transmission line cable temperature monitoring device which can realize online temperature monitoring and early warning of cables.
One technical scheme for achieving the above purpose is as follows: a power transmission line cable temperature monitoring device comprises a passive wireless sensor and a reader;
the wireless passive temperature sensor is arranged in the packaging box and comprises a PCB (printed Circuit Board) and a surface acoustic wave element, the upper surface of the surface acoustic wave element is flush with the open surface of the packaging box, and the packaging box is bound on the outer side of the cable through a polyvinyl chloride lantern ring, so that the surface acoustic wave element is tightly attached to the surface of the outer side of the cable;
the PCB board connects out through receiving and dispatching antenna, receiving and dispatching antenna accesss to nearest neighbour's pole and arranges along the pole, is equipped with the access in the bottom of pole receiving and dispatching antenna read the ware.
Further, the PCB board adopts heat conduction ceramic or FR4 material.
Further, when the PCB is made of FR4 material, the side surfaces of the PCB and the contact bonding surface are coated with copper, and the PCB area at the bottom of the surface acoustic wave element is also coated with copper.
Furthermore, heat-conducting silicone grease is coated on the connecting surface of the surface acoustic wave element and the PCB.
According to the power transmission line cable temperature monitoring device, the wireless passive temperature sensor and the transceiving antenna thereof are bound on the cable, the transceiving antenna is connected to the reader fixed at the bottom of the electric pole along the cable, and the reader transmits the excitation signal and acquires the echo signal representing the temperature information. After installing wireless passive temperature sensor, need not change the cable junction mode, the cable overall dimension is unchangeable, can directly assemble on current cable conductor. The outer packaging material is made of polyvinyl chloride which is the same as the outer insulating material of the cable, so that the temperature sensor is attached to the packaging material which is connected with the cable into a whole, the temperature of the cable can be accurately measured, and meanwhile, the system can monitor the temperature change condition of the contact in time through measures of reducing thermal resistance.
Drawings
Fig. 1 is a schematic view of an installation structure of a transmission line cable temperature monitoring device on a cable according to the present invention;
fig. 2 is a schematic structural diagram of a wireless passive temperature sensor of the transmission line cable temperature monitoring device of the invention;
FIG. 3 is a schematic diagram of a surface acoustic wave element of the power transmission line cable temperature monitoring device of the present invention;
fig. 4 is a schematic diagram of a specific position of a reader of the power transmission line cable temperature monitoring device according to the present invention.
Detailed Description
In order to better understand the technical solution of the present invention, the following detailed description is made by specific examples:
please refer to fig. 1-2. According to the transmission line cable temperature monitoring device, the wireless passive temperature sensor 1 is arranged in the packaging box, the wireless passive temperature sensor 1 comprises the PCB 4 and the surface acoustic wave element 3, and the upper surface of the surface acoustic wave element 3 is flush with the open surface of the packaging box. The packaging box is bound on the outer side of the cable through the polyvinyl chloride lantern ring 2, so that the surface acoustic wave element 3 is tightly attached to the surface of the outer side of the cable. The passive temperature sensor 1 receives radio frequency energy of an external reader through the transceiving antenna 5 and sends back a signal, and the polarization direction of the transceiving antenna 5 is over against the transceiving antenna of the reader.
The wireless passive temperature sensor 2 is made by adopting a surface acoustic wave technology, and comprises a PCB 4 and a surface acoustic wave element 3. The PCB 4 is made of heat conductive ceramic or FR4 material, and when FR4 material is used, copper is coated in a large area on the side where the PCB 4 and the contact are bonded, and copper is coated in the PCB region at the bottom of the surface acoustic wave element 3. The two copper-coated surfaces are connected through a plurality of metallized holes. And heat-conducting silicone grease is coated between the bottom of the surface acoustic wave element 3 and the PCB 4. The above measures are all for reducing the temperature difference between the surface acoustic wave element 3 and the cable to measure the accurate contact point temperature.
Referring to fig. 3, the surface acoustic wave element 3 is packaged with a piezoelectric substrate 8 on which an interdigital transducer 6 and a reflection grating 7 are printed. A radio frequency excitation signal sent by the reader 9 is captured by the interdigital transducer 6, generates surface acoustic waves in the piezoelectric substrate 8, is enhanced by the reflection grating 7, returns to the interdigital transducer 6, and is converted into a radio frequency echo signal through inverse piezoelectric effect and sent back. The wave speed of the surface acoustic wave is related to the temperature of the piezoelectric substrate, the wave speed determines the resonant frequency of the piezoelectric substrate 8, the reader 9 emits a series of radio frequency signals with different frequencies, and the resonant frequency is detected through amplitude mutation of echo signals, so that the current sensor temperature is obtained. When a plurality of sensors exist, the sensors can be distinguished by changing the center frequency, adjusting the spacing of the reflecting grids, realizing coding by the width and the like.
Referring to fig. 4, the PCB 4 is connected out through the transceiving antenna 5, the transceiving antenna 5 leads to the nearest electric pole and is arranged along the electric pole, and the reader 9 connected into the transceiving antenna is arranged at the bottom of the electric pole. The temperature data is uploaded after being summarized by the reader 9. The remote device evaluates the health condition of the line cable by comparing the actual current with the cable temperature rise data, and sends out an alarm signal when the temperature rise is found to be abnormal.
It should be understood by those skilled in the art that the above embodiments are only for illustrating the present invention and are not to be used as a limitation of the present invention, and that changes and modifications to the above described embodiments are within the scope of the claims of the present invention as long as they are within the spirit and scope of the present invention.