Study On System For Substation Electromagnetic Field Of High Voltage Based On B/S Structure

With the development of the power industry, the voltage level gradually improves.The number of high-voltage substation increases rapidly. Electromagneticenvironmental issues caused by power frequency electromagnetic fields becomeincreasingly prominent. Strong electromagnetic field will make long-term mannedsubstation attendants has some adverse physical symptoms such as dizziness andfatigue. The accuracy and stability of electronic products, including measurementdevices, communication systems, relay protection and so on, will also be disturbed.Therefore, it is necessary to establish a system for substation electromagnetic field ofhigh voltage to assess the electromagnetic environment inside the substation.This paper develops a system for substation electromagnetic field of high voltagebased on B/S structure and builds the main framework of the electromagneticenvironment data management and analysis platform for high voltage substation,which achieve some functions such as user management, data entry and modification,data query, print and electromagnetic field theory calculations. MFC technique is usedto develop the electrical drawing module. ActiveX control developed technology isintroduced to transfer the graphics module into an ActiveX control, which achievesthe interaction between the main body of the system and the graphics module. Matlabsoftware is used to compile the electromagnetic field calculation program. Thedynamic link library technology is used to achieve data transfer between matlab andMFC.The field sources of frequency electric field and magnetic field produced in thesubstation are analyzed in this paper, which are simplified as three linear conductors,namely three-phase finite wire, three-phase parabolic wire and three-phasesemi-infinite wire. This paper chooses to use the simulation charge method tocalculate the magnetic field of three-phase finite wire and three-phase parabolic wireon the basis of a more detailed study of the current frequency electric field andmagnetic field calculation method. Biot-Savart Law is used to deduce the functionwhich can calculate the magnetic field of three-phase finite wire, three-phaseparabolic wire and three-phase semi-infinite wire. When the issue of the electric field in the substation generated byincoming-outgoing transmission lines of high-voltage is talked, transmission line isconcerned as semi-infinite wire relative to the substation which is fixed at one end andthe other end is infinite. We cannot directly use the existing frequency electric fieldand magnetic field calculation methods of three-phase finite and infinite wire tocalculate its’. This paper combines simulation charge method and Genetic algorithmand develops a new way to calculate the electric field and magnetic field in thesubstation of the three-phase semi-infinite wire, namely “Simulation Charge-GeneticAlgorithm (CS-GA) method”. In CS-GA method, the effective calculating length isdetermined by genetic algorithm method’s optimization, which in other words,half-infinite length wire is substituted for limited length wire in calculating theelectric field intensity inside of the substation. The simulation results indicated thatCS-GA method is a relatively accurate, efficient and reasonable way on calculatingthe power frequency electric field inside of the substation.In this paper, a simplified mathematical model for a substation local area isestablished, which simplifies the linear conductor in this area as finite conductor,parabolic conductor and semi-infinite conductor. Simulation charge method andBiot-Savart Law is used to calculate the frequency electric field and magnetic field.