Research On The Method And Sensor Of Power Frequency Electric Field Measurement

The measurement of electric field has been used in many industries, such as power system, aerospace, medicine, etc. Electromagnetic environment problems induced by high voltage equipments arouse plenty of debates. Since State Grid Corporation of China put forward the strategy of constructing ultra-high-voltage (UHV) power grid in 2005, researches on the electromagnetic effects of UHV power grid to environment have sprung up in China. Obviously the debate on the electromagnetic pollution induced by UHV power grid would become more widely and last a long time. Compared with calculation, the measurement of electric field can demonstrate the environment situation more directly. In this paper, a power frequency electric field measure instrument is designed. The main contents include the following:①Learn the methods of electric field measurement. Alternating electric field sensor is chosen in this paper to meet the demand of measuring high-voltage power frequency electric field, based on the comparison of the different measuring methods, this kind of electric field sensor has the merits such as cheap, easy manufacture;②Learn the theory of alternating electric field measurement. Make a thorough research on the measure principle of spherical sensor. In this part, the spherical sensor's measure principles both in uniform electric field and in non-uniform electric field are discussed first, then the errors when measuring non-uniform electric field and when the sensor's axis not aligned with electric field's direction are analyzed;③Based on the measure principle, the influence of measure capacitor to signal sampled as current or voltage style is discussed first and then demonstrated by experiment data;④A power frequency electric field measure instrument is designed based on C8051F020 single-chip, in this apparatus an alarm system is implanted in according to national restrictions on human exposure to power frequency electromagnetic field;⑤Calibrate the instrument according to the data measured by oversea high-precision product;⑥Take contract tests with PMM8035A electromagnetic field measurement first under a 500kV transmission line and then in a substation, the results demonstrate the instrument made in this paper can not only work steadily in strong electric field environment but also measure the power frequency electric field correctly. Further work should improve the instrument's shortages to minimize the size, reduce the errors occurred when the electric field intensity is too small.