Research And Implementation Of Highly Reliable Monitoring System In The Nuclear Power Field

With the energy crisis intensified,the nuclear power industry is developing rapidly,and nuclear power safety is the most important in the development of nuclear energy.The loudspeaker broadcasting system is an important system for providing emergency protection in nuclear power plants.However,nuclear power plants are generally built in coastal areas with high air humidity,loudspeakers in nuclear power plants will inevitably have problems with equipment damage and transmission line aging.In order to ensure the reliability of the loudspeaker broadcasting system,a monitoring system for loudspeaker condition is urgently needed.Based on the actual requirements of the Daya Bay nuclear power plant and the actual installation of loudspeaker broadcasting system.In this thesis,a remote monitoring system based on loudspeaker condition monitoring is proposed,which is suitable for nuclear power field.The main task and innovations are as follows:Firstly,according to the premise that the installation of monitoring equipment in nuclear power plant can not add new lines,a scheme which integrates Power Line Carrier(PLC)technology and Wireless Sensor Networks(WSN)technology is proposed to guarantee the reliable communication with a distance of 1km.The scheme combines communication technology,automatic control technology and sensor technology to realize remote and reliable monitoring of the loudspeaker condition in the nuclear power field.Secondly,this paper analyses the realization principle and core technology of PLC and WSN technology,a PLC audio line data transmission scheme based on G3 standard and a wireless data transmission scheme based on Sub-GHz technology are proposed.In addition,the system architecture with PLC data concentrator,WSN data concentrator and wireless node as core modules is designed.Aiming at the problem of passive loudspeaker terminal's power supply,a method for outputting a sinusoidal excitation signal by using a digital power amplifier in the loudspeaker broadcasting system and transmitting the signal through the audio line to excite loudspeakers is proposed.The method enables the loudspeaker to emit a fixed frequency sound signal to be detected,and also provides power to the terminal detection modules.Then,the hardware design and software implementation of the monitoring system are completed.On the hardware,the simulation and design of the core circuit is realized according to the communication standard,and the hardware architecture of the system is designed.In the implementation of software,in order to realize the reliability of data transmission,the communication protocol of the monitoring system is developed.Aiming at the problem that many functions need to be completed by the core module of the system,a software implementation scheme based on TI-RTOS is proposed to enhance the flexibility of scheduling between tasks,so as to reduce the time loss of the monitoring process.Finally,in the test section,500 tests were performed on the overall function of the monitoring system in laboratory environment.The reliability of the monitoring system can be verified according to the monitoring accuracy of the system is over 98%.In the actual test of the nuclear power plant,the condition monitoring of loudspeakers farthest from the control room has been successfully realized.And the monitoring process takes only 50 s,which verified that the system meets the needs of practical applications.In summary,the terminal power supply and data transmission of the monitoring system are completed through the audio line,so that the additional erection of the communication line and the power supply line is avoided.The monitoring system has higher accuracy in judging the condition of loudspeaker,and the successful integration of PLC technology and WSN technology makes the data transmission stable.This paper provides a new solution for remote monitoring of the loudspeaker condition.