| The closed busway slot is a power distribution device with high efficiency in the power system.As a substitute for power cable,it is widely used in commercial buildings,large factories and subway airports.Busway slot is made up of multistage connections.The advantage of this structure is that it can meet the needs of distribution system's economic,reasonable and simple wiring.But at the same time,the connection of the busway slot is the weakest part,which leads to the increase of the contact resistance in the process of operation.The temperature rise has a serious effect on the performance of the busway,and the temperature rise above the specified value will lead to serious electrical accidents.The installation location of busway in the building makes on-site inspection difficult,so it is very important to monitor the connection of bus slot.The location monitoring is of no significance.It is significant to locate the outliers of monitoring parameters and help the staff to deal with faults quickly.Busway installation of the building interior environment is complex,in order to overcome the interference quickly find the busway connector temperature anomaly monitoring node,combined with Zigbee wireless monitoring busway system node network layout,using an improved RSSI(Received Signal Strength Indication)weighted centroid localization method.The simulation experiment proves the effectiveness of the positioning method,and realizes the visual display of the position of the phase anomaly node in the software.The main work is as follows:(1)Based on the Zigbee busway monitoring system and its network structure,the busway joint monitoring is adaptively sampled.When the temperature rises,the sampling frequency is increased.When the temperature rise reaches the set threshold,the abnormal node is determined and a positioning request is initiated.(2)In order to overcome the shelter and movement of the floors and walls,the reflection,refraction,diffraction and multipath effects of signals are generated,resulting in the ranging error of RSSI value,and the RSSI signal loss model is improved.The RSSI effective value optimization in order to reduce the randomness and variability of environmental parameters;the influence of the complexity of real-time correction of anchor node abnormal nodes nearby;using the corrected parameters of anchor node self-localization of secondary correction of measuring errors,improve the precision of ranging RSSI.(3)Two kinds of node coordinate calculation methods suitable for three-dimensional space are analyzed.Aiming at the problem that the quadrangle measurement method may not solve and the maximum likelihood estimation method has a large amount of computation,an improved weighted two center centroid computation method based on weighted centroid is proposed.RSSI received four anchor nodes form the largest four triangles with abnormal nodes,a triangular centroid calculation of anchor nodes consisting of a tetrahedron or quadrilateral centroid;RSSI distance as a weighted centroid,obtained two centroid coordinates,as the estimated abnormal node coordinate value.(4)The abnormal node coordinates are converted into physical location,namely,which layer of the building is located in the building,and how many distances to move to the specific floor after the arrival of the specified floor,and the software is designed to display the upper computer.3 RSSI ranging models are simulated and compared,which shows that the accuracy of the improved ranging method is improved.Referring to the simulation of a bus slot structure,the effectiveness of the improved method is verified.The abnormal point location of the monitoring parameters of the busway can make the staff know where to find the fault,and provide the convenience for the fast troubleshooting.The error of the simulation experiment satisfies the requirement of the location of the parameter anomaly point. |
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