| With the rapid development of power industry and Communication System in China,VSC-HVDC TECHNOLOGY has gradually become an advanced technology in power engineering applications.The failure of IGBT components is common in the flexible DC converter system due to its high temperature,how to monitor and adjust the temperature of IGBT components in real time is an important problem and research hotspot in recent years.The existing domestic monitoring means of the flexible direct converter valve is relatively scarce,which is limited to the judgment of the good or bad operation of the equipment and can not realize the monitoring and analysis of the process data.Therefore,monitoring the temperature state of the core component of the flexible HVDC converter valve and adjusting its power consumption in time are not only important to maintain the good working state of the system,but also to operate safely and reliably,it can also consolidate the international leading position of our country’s DC transmission technology and the future DC project upgrading and transformation services.In this thesis,the key technology of on-line monitoring of the temperature of the converter valve in the flexible HVDC transmission system is studied.In flexible HVDC system is studied in this thesis the flow valve,the key technology of temperature monitoring based on FBG temperature sensing principle,this thesis proposes a suitable for converter valve sensor design scheme of temperature measurement,the scheme will be slotted,radiator,the plan of integrated internal measurement can remedy the defects of the existing temperature measurement technology,real-time monitoring of IGBT component temperature,up a machine real-time warning,improve measurement accuracy and timeliness.The high precision temperature demodulation system and MZI type optical comb filter are studied.A double difference mathematical model index is proposed to measure the filter quality.A uniform design algorithm is proposed to solve the optical comb filter.The temperature demodulation system and the remote discrete control system suitable for the monitoring system are built according to the theoretical research.The research results show that the project enhances the reliability of the flexible DC converter valve to ensure power quality and utilization.In this whole thesis,the major work and origination are as follows:(1)A type is used to measure the MZI optical comb filter quality metrics have been proposed,suitable for different filter structure,the"double difference model" by the optical comb filter output curve and curve length difference between the target square wave and optical comb filter and the target square wave output curve integral integral area of difference between,capable of embodying the of the output function and the corresponding square wave function phase of the opposite sex,the thesis illustrates the "double difference value criterion" build process,its better than other metrics,can comb filter increased choice and speed.(2)A uniform design algorithm is proposed to solve the parameters of the comb filter.When the parameters are selected,this method can quickly and accurately solve the parameters and optimal values such as the product of the coupling coefficient and the effective sum length,and the length difference of the interference arm.In order to solve the complex and high-dimensional calculation problem of filter parameters,the nested uniform design is carried out based on the idea of recursive call to obtain more accurate parameters.The three MZI structures of the optical comb filter are analyzed by example and waveform simulation,and the performance of the comb filter is compared with that of genetic algorithm and particle swarm optimization algorithm.The research results show that the uniform design algorithm can solve the parameters,and the quality of the comb waveform is better,and the calculation efficiency is higher.Optimizing the structural parameters of the optical comb filter can effectively improve the crosstalk characteristics,enhance the channel isolation degree and the passband flattop degree,and has a good application prospect.(3)A sensor design scheme suitable for the temperature measurement of flexible converter valve is proposed.The scheme introduces FBG into the IGBT module and then encapsulates it,which can realize the integrated direct measurement and obtain the accurate real-time temperature monitoring value.It has the advantages of modularization,miniaturization and micro-power consumption,and solves the pain point in power grid engineering projects.Study temperature demodulation principle,structures,WDM optical comb filter demodulation scheme,the development platform based on c++ language and Qt 5 write online temperature demodulation software,engineering prototype has,through the sensitivity,stability,noise immunity test,for supporting platform and verify the feasibility of the system under high temperature,for soft straight system of converter valve provides a new method for on-line monitoring. |
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