Research Of Marine Cable On-line Monitoring System Based On ZigBee Technology

Malfunction of the marine power system may lead to unpredictable disaster as vessels are relatively isolated environment. Power cable’s parameters such as current, temperature can help people acknowledge the problem that may occur in the power system. And research about cable thermal aging need a big deal of real data about cable current and temperature. Current on-line cable monitoring system has a large number of wires to connect sensors with the main device, and this structure is not suitable for the narrow and complex space in vessels, or distributed monitoring spot on cables. To solve this problem, we developed a new on-line cable monitoring system which is based on ZigBee technology. This new system can monitor and store the current and temperature parameters of several spots on cables.This system is based on ZigBee technology. We choose RF module CC2430, which is produced by Wuxianlong Company, as basic hardware to build ZigBee network. And we use Z-stack, which is developed by TI company, as the core software of the system.The wireless network of the system used tree topology. There are three kinds of nodes that are different form each other in hardware structure. One of them is called Collecting Node, and it works as the coordinator in this ZigBee network. Collecting Node’s mission includes building a new ZigBee network, displaying and storing cable parameter gathered from other nodes, and providing a operation interface for users. The hardware of Collecting Node consists of LCD, keys, clock chip and MicroSD card. Another kind of node is named Sensor Node. Normally, they work as the end-devices in the wireless network. If constant power source can be provided for Sensor Node, they can also work as routers. There are3current sensors,3temperature sensors and1temperature and humidity sensor hooked on each of Sensor Node. In every work cycle, Sensor Nodes gather the data of the cables from sensors hooked on them and send to Collecting Node wirelessly, and spend rest of time in sleep mode to save power. Sensor Nodes need to optimize their radio frequency output power to reduce the power consumption of battery,and an appropriate output power may lead to less electromagnetic interference. The third kind of node is call battery node. Their hardware merely include a ZigBee module and a battery. They are used to connect the Sensor Nodes that can not be covered by wireless network. And their only task is routing the data from Sensor Node to Collecting Node.To test the function of this new marine cable monitoring system, we built a experimental platform which consist of a piece of marine cable and a constant current source. The cable monitoring system was applied on the cable of the experimental platform, and a wireless sensor network was set up. And the power consumption of Sensor Node was assessed. It approved that the system can complete the job of displaying and storing the parameters of multipoint on marine cables.