CN102736049B - An Analog Dielectric Loss Device with Wireless Remote Control - Google Patents

Abstract

The invention discloses a wireless-remote-control simulated dielectric loss device, which comprises a singlechip, a signal conditioning circuit, a phase-shifting circuit, a constant current output circuit and a infrared signal receiving circuit, wherein the signal conditioning circuit is used for converting a current signal flowing through a standard capacitor to a voltage signal; the phase-shifting circuit is used for performing phase shift on the input voltage signal, and the phase-shifting circuit comprises a plurality of electronic phase shifters, and an input end of each electronic phase shifter is connected with an output end of the signal conditioning circuit through an electronic switching circuit, and an control end of each electronic switching circuit is connected with a corresponding loss value gear output signal output end of the singlechip; and the constant current output circuit is used for converting a phase-shifted voltage signal output by a phase shifter unit to a phase-shifted current signal so as to be output to a tested end of a dielectric loss tester to be tested; and the infrared signal receiving circuit is connected with a signal input port of the singlechip. The wireless-remote-control simulated dielectric loss device provided by the invention is wirelessly controlled by remote control, and the security of operating personnel is ensured, and the work efficiency is also improved.

Description

An Analog Dielectric Loss Device with Wireless Remote Control

technical field

The invention relates to the technical field of dielectric loss measuring equipment in power systems, in particular to a remote-controllable analog dielectric loss device.

Background technique

The insulation status of high-voltage electrical equipment plays a vital role in the safe operation of power systems. Many accidents in the power system are caused by insulation problems. In order to ensure the safe operation of the power system, an insulation test must be carried out. The dielectric loss measurement test is a highly sensitive insulation test.

At present, most dielectric loss measurements use high-voltage capacitor bridges as test equipment, and the accuracy of the measurement results is directly related to the safety of power production. In order to ensure the reliability of the measurement results, it is necessary to regularly calibrate the test equipment.

The standard loss method or the standard bridge comparison method is commonly used for the calibration of the dielectric loss bridge (or dielectric loss tester).

The standard loss method is to use the calibrated dielectric loss bridge to measure standard loss devices with different capacitance and dielectric loss values, and then obtain the measurement error. The standard bridge comparison method is to use a standard bridge and a bridge to be verified to measure the same tested product at the same time, and then calculate the deviation from the standard bridge. No matter which method is used, a loss device is required.

Usually the laboratory or field is used to calibrate various dielectric loss testers. The standard loss device used is composed of a standard capacitor connected in series with different resistors to achieve the purpose of adjusting different loss values. The working principle of this type of loss device is simple, but it has the following disadvantages:

1. When the loss value is large, the series resistor needs to withstand high voltage and high power. It cannot meet the withstand voltage requirements of the low-voltage end of general standard capacitors. And the resistance power is too large, which is not suitable for commercial production.

2. When a standard capacitor with a small capacity is selected, the resistance value that needs to be connected in series is large when the dielectric loss value is large, and it is easily affected by distributed capacitance and resistance changes (large resistance resistance is easily affected by temperature and humidity). The loss value is unstable.

3. Usually the dielectric loss value (tgδ) of this model can only be 0~0.1.

4. The loss value shift needs to be switched by a mechanical switch, and the contacts are prone to aging and unsafe.

Contents of the invention

The technical problem to be solved by the present invention is to aim at the problems existing in the existing standard loss devices when calibrating various dielectric loss testers. From the perspective of the stability of the loss device and minimizing the limitation of environmental conditions, combined with the high-voltage capacitor bridge Forward and reverse wiring characteristics, and provide an analog dielectric loss device that can be wirelessly controlled. The wireless remote-controlled simulated dielectric loss device can easily check the test system to eliminate faults in the test. Simultaneously, the analog dielectric loss device capable of wireless remote control of the present invention can also be used in the calibration work of the high-voltage capacitor bridge in the metering department.

The technical problem to be solved by the present invention can be realized through the following technical solutions:

An analog dielectric loss device capable of wireless remote control, comprising:

A single-chip microcomputer, said single-chip microcomputer has several loss value gear output signal output terminals;

A signal conditioning circuit for converting the current signal flowing through the standard capacitor into a voltage signal, the input terminal of the signal conditioning circuit inputs the current signal that will flow through the standard capacitor;

A phase shifting circuit for phase shifting the input voltage signal, the phase shifting circuit includes a number of electronic phase shifters, wherein the input end of each electronic phase shifter is connected to the output of the signal conditioning circuit through an electronic switch circuit terminal connection, the control terminal of each electronic switch circuit is connected with the corresponding loss value gear output signal output terminal in the single-chip microcomputer;

A constant current output circuit for converting the phase-shifted voltage signal output by the phase shifter unit into a phase-shifted current signal and outputting it to the tested end of the dielectric loss tester; the constant current output circuit The input end is connected to the output end of each electronic phase shifter in the phase shifting circuit;

An infrared signal receiving circuit connected to the signal input port of the single-chip microcomputer;

An infrared transmitter that sends a loss value gear signal to the infrared signal receiving circuit.

In a preferred embodiment of the present invention, a keyboard for inputting loss value gear signals is also connected to the signal input port of the single-chip microcomputer.

In a preferred embodiment of the present invention, a display for displaying the currently set dielectric loss gear parameter is connected to the display signal output port of the single-chip microcomputer.

The wireless remote control analog dielectric loss device in the present invention adopts the current signal phase-shifting method to simulate different dielectric loss values, has low input impedance, is not affected by the length of the test lead, and does not appear high voltage at the standard capacitor measurement terminal. . Since the phase shifting components are all low-temperature drift resistors and capacitors, the loss can be kept stable at room temperature. The dielectric loss value shift adopts an electronic switch, which is safe and reliable without mechanical electric shock. The shifting operation can be controlled wirelessly by the remote controller, which ensures the safety of the operator and improves the work efficiency.

Description of drawings

Fig. 1 is a schematic diagram of the electrical principle of the present invention.

Detailed ways

In order to make the technical means, creative features, goals and effects achieved by the present invention easy to understand, the present invention will be further described below in conjunction with the accompanying drawings.

Referring to Fig. 1, a wireless remote control analog dielectric loss device shown in the figure includes a single-chip microcomputer 100, and the chips of the single-chip microcomputer 100 adopt C8051F120/2/3/6, C8051F130/2, and C8051F020/2 type chips. The single-chip microcomputer 100 has several loss value gear output signal output terminals.

The input terminal of the signal conditioning circuit 200 is connected to the current signal flowing through the standard capacitor, and the current signal flowing through the standard capacitor is digital-to-analog converted into a voltage signal for output.

The phase shifting circuit 300 includes several electronic phase shifters 301, 302...30n, and the electronic phase shifters 301, 302...30n are all composed of operational amplifiers OPA2277 and peripheral circuits. The input terminals of the electronic phase shifters 301, 302...30n The electronic switch circuits 401, 402 ... 40n are connected to the output terminals of the signal conditioning circuit 200, and the electronic phase shifters 301, 302 ... 30n are connected to the corresponding loss value gear output signal output terminals in the single-chip microcomputer 100; the single-chip microcomputer 100 outputs different losses The output signal of the value gear triggers the conduction of different electronic phase shifters 301, 302...30n, and the different electronic phase shifters 301, 302...30n shift the phase of the input voltage signal. Adopt electronic switch circuit 401, 402...40n, no mechanical electric shock, safe and reliable.

The voltage signals phase-shifted by the electronic phase shifters 301, 302...30n are input to the constant current output circuit 500 through the output terminals of the electronic phase shifters 301, 302...30n and the input terminal of the constant current output circuit 500, and the constant current output circuit 500 transforms the phase-shifted voltage signals output by the electronic phase shifters 301, 302...30n into phase-shifted current signals and outputs them to the tested end of the dielectric loss tester under test.

The loss value gear output signal output by the single-chip microcomputer 100 can be controlled by the infrared signal receiving circuit 600 or the keyboard 700 connected to the signal input port of the single-chip microcomputer 100 . The infrared transmitter sends the loss value gear signal to the infrared signal receiving circuit 600 or inputs the loss value gear signal through the keyboard 700 . After calculation, the single-chip microcomputer 100 outputs output signals of different loss value gears. A display 800 for displaying the currently set dielectric loss gear parameter is also connected to the display signal output port of the single-chip microcomputer 100 .

Main technical indicators of the present invention are as follows:

Rated working environment temperature: 0～40℃

Rated working environment humidity: 30% to 80%

Rated signal frequency: 50Hz, other frequency points can be designed as required

Working power: DC 16V, built-in rechargeable lithium-ion battery

Charger working power: 220V/50Hz

Input current range: 100uA ~ 100mA (can be expanded as needed)

Output current range: 100uA ~ 100mA (can be expanded as needed)

Output current error: ±0.2% of input current

Analog dielectric loss error: ±(0.2% of reading+0.0001)

Input impedance: 2Ω

Load capacity: ≤20Ω.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and that described in the above-mentioned embodiments and the description only illustrates the principles of the present invention, and the present invention also has various aspects without departing from the spirit and scope of the present invention. Variations and improvements all fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (1)

1. a simulation medium loss device that can wireless remote control, is characterized in that, comprising:

One single-chip microcomputer, described single-chip microcomputer has several loss value gear output signal output terminals;

In order to the current signal of the standard capacitor of flowing through is converted to the signal conditioning circuit of voltage signal, the input end of described signal conditioning circuit is inputted the current signal of the standard capacitor of flowing through;

In order to the voltage signal of input is carried out to the phase-shift circuit of phase shift, described phase-shift circuit comprises some electronic phase shifters, wherein the input end of each electronic phase shifter is connected with the output terminal of described signal conditioning circuit by an electronic switching circuit, and the control end of each electronic switching circuit connects with the corresponding loss value gear output signal output terminal in described single-chip microcomputer;

In order to the voltage signal after phase shift of phase-shift circuit output is transformed into the constant current output circuit that exports the tested end of tested dielectric loss measuring instrument through the current signal of phase shift to; The input end of described constant current output circuit is connected with the output terminal of each electronic phase shifter in described phase-shift circuit;

One is connected to the infrared signal receiving circuit of the signal input of described single-chip microcomputer;

One infrared transmitter to described infrared signal receiving circuit transmission loss value gear signal;

On the signal input of described single-chip microcomputer, also connect a keyboard in order to input loss value gear signal;

Display delivery outlet at described single-chip microcomputer also connects one in order to show the display of the dielectric loss gear parameter of current setting.