| With the increasing demand for traditional non-renewable energy,the energy crisis and ecological problems have caused the development and utilization of new energy to gradually become a research focus for scholars at home and abroad.Since the thermoelectric power generation technology that can convert domestic and industrial waste heat energy into electrical energy has attracted attention,its application in the field of cathodic protection has also been expanded.The substation grounding grid is easy to corrode in the soil,and cathodic protection is a very effective and economical way to solve this problem.However,the cathodic protection method of sacrificial anode does not perform well in the environment with high soil resistivity,and the anode needs to be replaced frequently;the cost and maintenance cost of the traditional cathodic protection method of impressed current is relatively high and the area is large,So cathodic protection law is very important.Based on the analysis of the principle of thermoelectric power generation and the volt-ampere characteristics of thermoelectric cells,this paper studies the working characteristics of thermoelectric materials and the arrangement characteristics of semiconductor thermoelectric cells,and designs the structure of thermoelectric power generation components and their hot and cold ends.The overall cathodic protection system is designed using Simulink software.The system includes a maximum power point tracking module based on the disturbance observation method,a Boost boost circuit,a PI-controlled voltage stabilization module,and an energy storage module with bidirectional DC-DC conversion,and conducted a simulation analysis of the designed cathodic protection system.By selecting the BQ25504 chip and TPS78001 voltage regulator chip that can realize the energy harvesting of the maximum power point tracking mode,the cathodic protection device is built with the peripheral circuit they match,and the designed circuit and the temperature difference are used to generate electricity.After the components are connected,a simulation analysis is performed.The potential standard of cathodic protection was studied,and the protection effect of the device was tested through simulation tests.Finally,according to the scale and arrangement characteristics of the grounding grid of Shangzhidong Substation,the actual process design of the thermal cathodic protection device designed in this paper is applied to this substation.Field survey data and heat source test results show that the upper casing of the transformer has a relatively high temperature,which is sufficient as a heat source for the thermoelectric battery.The simulation analysis results show that the cathodic protection system designed in this paper can continuously provide a stable protection current for the grounding grid metal.Through the temperature difference cathodic protection simulation test,the potential of the steel plate of the grounding body using this device was measured,and the result was-0.936 V,which met the requirements of the protection potential.Through the process design,the amount of protection current required by the substation and the type and amount of auxiliary anodes are determined,and finally the area of each device that can protect the grounding grid is obtained. |
