This paper puts forward an on-line monitoring system of power transformer which could online collect multiple physical parameters of power transformer at the same time without using electricity sensor. In this case, the sensor will not affected by the strong electric field, magnetic field and electromagnetic wave. The system analysis the running state of power transformer according to physical parameters accurately, as current technology can only measure single physical parameters, it can solve this problem that the measurement results lack of association. Moreover, the system improves the reliability of power transformer operation and security of online measurement, ensuring the safe operation of power system.

Power transformer of rural is prone to theft and damage, we always put the transformer in the house or take care of it to solve this problem, however, the shortage of these two methods is to increase the cost of power supply, bringing inconvenience for people's production and life. This system is the device that can overcome the shortage of technology and provide base-station dual positioning of GPS and GSM, it will locate and track the transformer, preventing the transformer to stolen effectively.

The estimate of the remaining capacity of power battery is one of the most important function of battery management system. Using traditional methods is difficult to estamate the remaining capacity, this paper put forward a new method which is based on the battery model and extended Kalman filter.Then carries on the concrete analysis and discussion.