| Recent years,people's demand for electric power increase continually with the rapid growth of national economy and the expansion of cities and towns.For the feature that primary energy source and productive forces are imbalance in our country,important electric energy bases are often thousands of kilometers away from load center,that makes long-distance,high-voltage electricity transmission an inevitable choice.To guarantee the quality and reliability of power supply,it's necessary to build substations that can support high voltage grid in densely populated region,and the potential hazard to human body caused by power frequency electric field of high-voltage substations draws the attention of people gradually,that includes electric shock caused by electrostatic effect of power frequency electric field and the short term and long term effect on organisms when exposing to power frequency electric field.There are various kinds of conductors complexly placed in 500kV substations,that make power frequency electromagnetic field strong and complex in and near substation,simulation and analysis of electric field before building up a substation has contribution to the optimization design of the structure of substation,that makes the research of simulation method of electric field in substation an important subject.The paper aiming at the problem of simulation and measurement of electric field in substations,choosing Charge Simulation Method(CSM)as the foundation algorithm of simulation,carry out research on the application of CSM to substations,the effect of conductor height on the electric field in substation,and the design of electric field measuring system,with three points of details and innovations as follows:(1)Traditional CSM are usually used to calculate the electric field of long-distance overhead transmission line,assuming the jointed conductors has equal sag and span.The paper base on the Theory of CSM,improving CSM using distributed parameter according to the feature of substation conductor that are short-spanned,various-shaped,densely-placed and complexly-jointed.The improved CSM can superimpose the electric field of conductors of different span and sag,and it can be applied to calculating electric field in substations.(2)The paper proposes a sensitivity coefficient model for electric field based on CSM,sensitivity coefficient is acquired by using the electric field formula to get the derivation of the conductor height factor.The model can be used to analyze the variation tendency of electric field,avoiding calculating electric field twice when using CSM,speeding up calculation.(3)Using a flat plate capacitance as electric field sensor,Designing the area and measuring capacitance of the sensor,an electric field strength meter based on MSP430 microcontroller is made using this sensor.The amplify,filter,rectification,measuring and control circuit are designed,software is written.The instrument has the functions of measure and display electric field,and alert when electric field tensely exceeds limitation. |
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