Abstract: A warning device for preventing underground cables against accidental excavation comprises an optical fiber vibration sensor having a mode recognition function, a signal processing unit, a wireless communication unit and a power supply unit, wherein the signal processing unit is connected to the optical fiber vibration sensor, the wireless communication unit and the power supply unit, and the optical fiber vibration sensor is installed within a set range of a cable and is used to monitor vibration signals around the cable, so that once a behavior possibly endangering the cable occurs, an alarm is given out in time to reduce power transmission and transformation accidents. Compared with the prior art, the warning device has the advantages of low false alarm rate, rapid response and accurate localization region.

Abstract: A device for preventing cables against external damage based on sound source localization comprises a power supply unit, and a sound source sensor unit, a camera unit, a signal processing unit and a wireless communication unit which are electrically connected to the power supply unit. The signal processing unit is connected to the sound source sensor unit, the camera unit and the wireless communication unit. The camera unit is associated with the sound source sensor unit. When the sound source sensor unit recognizes a target signal, the signal processing unit sends a trigger signal to the camera unit, and then the camera unit is triggered to replay a surveillance video to determine whether or not a target really exists. Compared with the prior art, the device has the advantages of being good in safety, high in reliability and the like.

Abstract: The method for state estimation based on the measured data of data-acquisition system in electric power system relates to the field of power system analysis technique, characterized in that the method comprises: distributing the said measured data into an operating power system to form a calculation model, defining the injection power of the link nodes as 0 and taking the maximum active power output, maximum reactive power output of the generator as the constraints, constructing a mathematic model for estimation, resolving the optimum solution of the voltage amplitude and voltage phase angle for every node, and calculating the estimated values of the voltage, the active power and the reactive power by using the optimum solution of the state variables, if the difference between the measured value and the estimated value was less than a parameter ? that is predetermined under different voltage levels, the estimated value is qualified.