Anti-interference electric field measurement system

Abstract

The invention specifically relates to an anti-interference electric field measurement system, and belongs to the technical field of power equipment measurement. The device comprises an electric field sensor, two groups of conditioning circuits, a first digital-to-analog converter, a second digital-to-analog converter and an adder, two groups of conditioning circuits are added on the basis of a traditional capacitive electric field sensor and are respectively connected to the center and the edge of the capacitive electric field sensor through twisted pairs; twisted pairs adopted by the two groups of conditioning circuits have the same parameters and are close to each other, so that the same interference is ensured; meanwhile, components adopted by the two groups of conditioning circuits are completely the same, so that the offset voltages of the components are ensured to be the same; and finally, the models obtained by the two groups of conditioning circuits are processed by an adder, so that an interference-removed electric field signal can be obtained, and the problem that an existing capacitive electric field sensor is easily influenced by an edge electric field and in-station environment interference during electric field measurement in a transformer substation is solved. And the accuracy of electric field intensity measurement in the transformer substation is greatly improved.

Description

Technical Field

[0001] The invention specifically relates to an anti-interference electric field measurement system, belonging to the technical field of power equipment measurement. Background Art

[0002] In recent years, with the promotion of the application of one-button sequential control technology, the use of heterogeneous sensors to judge the switch position has attracted more and more attention. The switch opening and closing is accompanied by a sudden change in the electric field strength, which is a relatively superior judgment method. The electromagnetic environment in the substation is complex, and the interference signal is particularly significant at the moment of switch opening and closing. At this time, the accurate measurement of the electric field strength faces challenges. Whether the electric field strength can be accurately measured at this time is directly related to whether the electric field characteristic quantity can be used for switch position judgment in one-button sequential control.

[0003] Electric field sensors based on capacitor plates are currently a more common solution and can be used for daily maintenance and live detection of primary substation equipment. However, due to the complex electromagnetic environment at the substation site, such as the presence of multiple charged bodies, especially charged bodies with different voltage levels, traditional electric field sensors based on single-pole plates will receive strong electromagnetic interference, resulting in inaccurate measurement of electric field strength. Summary of the invention

[0004] The technical problem to be solved by the present invention is: how to accurately measure the electric field strength in a transformer substation.

[0005] In order to solve the above technical problems, the technical solution proposed by the present invention is: an anti-interference electric field measurement system, comprising an electric field sensor, two groups of conditioning circuits, a first digital-to-analog converter, a second digital-to-analog converter and an adder; one end of one group of conditioning circuits in the two groups of conditioning circuits is connected to the center of the electric field sensor through a twisted pair, and the other end is connected to the first digital-to-analog converter; one end of the other group of conditioning circuits in the two groups of conditioning circuits is connected to the edge of the electric field sensor, and the other end is connected to the second digital-to-analog converter; the first digital-to-analog converter is connected to the adding end of the adder, and the second digital-to-analog converter is connected to the subtracting end of the adder; the electric field sensor comprises an upper plate, a lower plate and an equipotential ring; the radius of the upper plate is smaller than the radius of the lower plate; the upper plate and the equipotential ring are located in the same plane and are parallel to the plane where the lower plate is located; there is no electrical connection between the upper plate and the equipotential ring; the upper plate, the lower plate and the equipotential ring are electrically insulated; the conditioning circuit comprises an operational amplifier, two basic resistors, two conditioning resistors and a potential bias device; one end of one of the two basic resistors is connected to the non-inverting input end of the operational amplifier, and the other end is connected to the potential bias device; the other basic resistor of the two basic resistors is connected to the inverting input end of the operational amplifier; the two conditioning resistors A conditioning resistor in One end of the resistor is connected to the non-inverting input end of the operational amplifier, and the other end is grounded; the two conditioning resistors Another conditioning resistor in One end of is connected to the output end of the operational amplifier, and the other end of is connected to the inverting input end of the operational amplifier.

[0006] The beneficial effects of the present invention are as follows: on the basis of the traditional capacitive electric field sensor, the present invention adds two groups of conditioning circuits which are respectively connected to the center and edge of the capacitive electric field sensor through twisted pair cables; the twisted pair cables used by the two groups of conditioning circuits have the same parameters and are close to each other, ensuring that the interference they receive is the same; at the same time, the components used by the two groups of conditioning circuits are also exactly the same, ensuring that the offset voltages of the components are the same; finally, the models obtained by the two groups of conditioning circuits are processed by an adder to obtain an electric field signal with interference removed, thereby overcoming the problem that the existing capacitive electric field sensor is easily affected by the edge electric field and the station environment when performing electric field measurement in the substation, and greatly improving the accuracy of the electric field strength measurement in the substation. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a structural schematic diagram of an anti-interference electric field measurement system of the present invention.

[0008] Figure 2 It is a structural schematic diagram of an electric field sensor in an anti-interference electric field measurement system of the present invention. DETAILED DESCRIPTION

[0009] The following is a further description of an anti-interference electric field measurement system of the present invention in conjunction with the accompanying drawings and specific embodiments.

[0010] Example

[0011] The anti-interference electric field measurement system in this embodiment is as follows: Figure 1 As shown, it includes an electric field sensor, two groups of conditioning circuits, a first digital-to-analog converter, a second digital-to-analog converter and an adder; one end of one group of conditioning circuits in the two groups of conditioning circuits is connected to the center of the electric field sensor through a twisted pair, and the other end is connected to the first digital-to-analog converter; one end of the other group of conditioning circuits in the two groups of conditioning circuits is connected to the edge of the electric field sensor, and the other end is connected to the second digital-to-analog converter; the first digital-to-analog converter is connected to the adding end of the adder, and the second digital-to-analog converter is connected to the subtracting end of the adder.

[0012] like Figure 2As shown, the electric field sensor includes an upper plate, a lower plate and an equipotential ring; the radius of the upper plate is smaller than the radius of the lower plate; the upper plate and the equipotential ring are located in the same plane and are parallel to the plane where the lower plate is located; there is no electrical connection between the upper plate and the equipotential ring; the upper plate, the lower plate and the equipotential ring are electrically insulated.

[0013] The conditioning circuit includes an operational amplifier, two basic resistors, and two conditioning resistors. and a potential bias device; one end of one of the two basic resistors is connected to the non-inverting input terminal of the operational amplifier, and the other end is connected to the potential bias device; the other basic resistor of the two basic resistors is connected to the inverting input terminal of the operational amplifier; two conditioning resistors A conditioning resistor in One end is connected to the non-inverting input terminal of the operational amplifier, and the other end is grounded; two conditioning resistors Another conditioning resistor in One end of is connected to the output end of the operational amplifier, and the other end is connected to the inverting input end of the operational amplifier.

Claims

1. An anti-interference electric field measurement system, characterized in that: The invention comprises an electric field sensor, two groups of conditioning circuits, a first digital-to-analog converter, a second digital-to-analog converter and an adder; one end of one group of conditioning circuits in the two groups of conditioning circuits is connected to the center of the electric field sensor through a twisted pair, and the other end is connected to the first digital-to-analog converter; one end of the other group of conditioning circuits in the two groups of conditioning circuits is connected to the edge of the electric field sensor, and the other end is connected to the second digital-to-analog converter; the first digital-to-analog converter is connected to the adding end of the adder, and the second digital-to-analog converter is connected to the subtracting end of the adder; the electric field sensor comprises an upper plate, a lower plate and an equipotential ring; the radius of the upper plate is smaller than the radius of the lower plate; the upper plate and the equipotential ring are located in the same plane and are parallel to the plane where the lower plate is located; there is no electrical connection between the upper plate and the equipotential ring; the upper plate, the lower plate and the equipotential ring are electrically insulated; the conditioning circuit comprises an operational amplifier, two basic resistors, two conditioning resistors and a potential biasing device; One end of one of the two basic resistors is connected to the non-inverting input terminal of the operational amplifier, and the other end is connected to the potential biasing device; The other basic resistor of the two basic resistors is connected to the inverting input terminal of the operational amplifier; the two conditioning resistors A conditioning resistor in One end of the resistor is connected to the non-inverting input end of the operational amplifier, and the other end is grounded; the two conditioning resistors Another conditioning resistor in One end of is connected to the output end of the operational amplifier, and the other end of is connected to the inverting input end of the operational amplifier.

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