CN201876537U - Detector for online arrester monitoring device - Google Patents

Abstract

The lightning arrester on-line monitoring device tester involves a temperature compensation circuit, a nonlinear compensation circuit, a standard sine wave signal generator, a voltage and current conversion device, R232, a single-chip microcomputer, a liquid crystal display and a keyboard. The temperature compensation circuit and the non-linear compensation circuit arranged side by side are respectively connected with the standard sine wave signal generator, and the standard sine wave signal generator is connected to the voltage-current conversion device and the single-chip microcomputer at the same time, and the single-chip microcomputer is connected to R232 at the same time. to the LCD display and keyboard. The standard sine wave signal generator generates a fixed voltage signal, and the voltage-current conversion device converts this voltage signal into the required current signal of 0.2mA~10mA. The single-chip microcomputer is the control core, which mainly completes the man-machine interface function and data interface function. The human-machine interface function is composed of a liquid crystal display and a keyboard. The user sets parameters through the keys, and the system displays the parameters and test results through the liquid crystal display. The utility model has the advantages of simple overall structure, convenient operation and use, good stability and high reliability.

Description

Surge arrester online monitoring device detector

technical field

The utility model relates to an online detection device of a lightning arrester monitoring device, in particular to a detector for a lightning arrester online monitoring device.

Background technique

Measuring the AC leakage current under the operating voltage is the main function of the metal oxide arrester on-line monitor. Through the size of the leakage current, the on-site operation status of the metal oxide arrester can be judged to determine whether it is damaged or whether it is affected by water or damp. At present, the lightning arresters in the substation have been equipped with lightning arrester online monitoring devices. Through the operation in recent years, the following problems have been found: 1. In the routine preventive tests after the lightning arresters are put into operation, only the action of the lightning arrester online monitor can be monitored. There is no way to judge the correctness of the current indication range. 2. During the operation of the lightning arrester online monitoring device, affected by the environmental conditions, the indication is often incorrect, which makes the operating personnel doubt its operation safety. Some lightning arrester on-line monitor indications are incorrect due to the operating environment, for example, in rainy or foggy weather, the leakage current indication generally increases or the alarm indicator light is activated; and sometimes the indication value is small or zero, it may be the insulation base of the arrester Insulation level drop or short circuit. Based on the above reasons, it is found that in the routine preventive test after the arrester is put into operation, only the action of the arrester on-line monitor can be detected, and the action indicator is only used to record the number of actions of the arrester under overvoltage, and its current indication There is no means of judging the correctness of the range is the problem. Although the regulations do not stipulate the calibration of the leakage current range of the arrester on-line monitor in the preventive test, from the actual operation situation, the calibration of the leakage current range of the arrester on-line monitor through the preventive test is the key to judging whether the monitor is normal or not. No important means.

Contents of the invention

The purpose of this utility model is to overcome the deficiencies of the prior art and provide a lightning arrester on-line monitoring device detector, according to the on-line monitor milliampere meter detection circuit principle and the counter action principle, in accordance with the national metrology verification regulations (JJG124-93 "Verification Regulations for Ammeters, Voltmeters, Power Meters, and Resistance Meters") stipulates that the online monitor milliampere meter detection and counter action detection should be integrated to facilitate on-site use.

The lightning arrester online monitoring device detector described in the utility model involves a temperature compensation circuit, a nonlinear compensation circuit, a standard sine wave signal generator, a voltage-current conversion device, R232, a single-chip microcomputer, a liquid crystal display and a keyboard. The temperature compensation circuit and the non-linear compensation circuit arranged side by side are respectively connected with the standard sine wave signal generator, and the standard sine wave signal generator is connected to the voltage-current conversion device and the single-chip microcomputer at the same time, and the single-chip microcomputer is connected to R232 at the same time. to the LCD display and keyboard. The 50Hz standard sine wave signal generator generates a fixed voltage signal, and the voltage-current conversion device converts this voltage signal into the required current signal of 0.2mA~10mA. Since the external temperature change will cause the output voltage amplitude to drift, record the output voltage of the standard sine wave signal generator at different temperatures, and obtain the temperature coefficient table, with a step size of 5°C, according to the temperature collected by the semiconductor temperature sensor value, adding the temperature system to a standard sine wave signal generator. Due to the non-linearity of the circuit transmission parameters, the output current signal of 0.2mA~10mA has a certain non-linearity. In order to compensate for this error, the output current is measured at a step size of 0.1mA to measure the current value in the entire range. Multiplication and nonlinear fitting are performed to obtain a fitting 5th degree polynomial, and this fitting coefficient is compensated into a standard sine wave signal generator circuit. After temperature compensation and nonlinear compensation processing, the linearity and stability of the current generator circuit are greatly improved, fully meeting the test requirements of the system. In order to obtain maximum current amplitude and waveform steepness, the inductance of the discharge loop must be minimized. Therefore, when designing an inrush current device, its rationality should be fully considered in terms of the structure of the device and the choice of components.

Capacitive energy storage: Energy storage in the charging circuit is an important part of the inrush current device. It is impossible to directly obtain a strong inrush current with a certain waveform from the grid. Generally, the energy is stored in a longer period of time by means of an energy storage system. Store it for a long time, and then release it instantaneously to obtain a strong shock current. There are many ways to store energy, such as capacitive energy storage, inductive energy storage, mechanical energy storage, battery energy storage, etc. Among them, capacitive energy storage is the most widely used and the technology is mature. In the impulse current device scheme, we adopt the capacitive energy storage method. Based on the principle of reducing inductance, we choose low inductance pulse capacitors. When wiring, keep the wires as short as possible, and the wires with the same direction of current as far away as possible to make the mutual inductance as small as possible; while the wires with different current directions are as close as possible to make the mutual inductance as large as possible. According to the calculation of the energy calculation formula W=1/2CU ² of the capacitor, it is concluded that the value of the capacitor is about 20μF, and when the charging voltage of the capacitor is 700-800V, through the triggering of the gap, a waveform of 8/20μs and a current amplitude of 100A can be obtained. Inrush current output.

Wave modulation resistor: In the impulse current device, the function of the wave modulation resistor is to adjust the output waveform parameters of the impulse current. In order to make the loop generate as large an inrush current as possible, the equivalent inductance of the loop is required to be as small as possible, which brings certain difficulties to the design of the modulating resistor. On the one hand, the equivalent inductance of the modulating resistor is required to be as small as possible. The shock current wave of the duration, the wave-modulating resistor must have an appropriate resistance value. The equivalent resistance and equivalent inductance of the modulating resistor are a pair of contradictory parameters. When the resistance value is large, the corresponding inductance must also be large. Therefore, when we choose to make wave-modulating resistors, manganese-copper wire, an alloy material with high resistivity and good stability, is the first choice. In the winding manufacturing process, we adopted the S-fold method, which automatically offsets the inductance of the resistor through the direction of the current in and out, and obtained a satisfactory effect.

As the single-chip microcomputer in the whole machine is the control core of this system, it mainly completes the man-machine interface function and data interface function. The human-machine interface function is composed of a liquid crystal display and a keyboard. The user sets parameters through the keys, and the system displays the parameters and test results through the liquid crystal display. The data interface communicates with the host computer through R232, and uploads the measurement data to the host computer.

The detection instrument for the on-line monitoring device of the arrester described in the utility model has the advantages of simple overall structure, convenient operation and use, good stability and high reliability, and can perform on-site detection on the on-line monitoring device of the zinc oxide arrester. After starting up, the instrument automatically performs current calibration. After the current verification is completed, the counter operation check is automatically performed.

Description of drawings:

Accompanying drawing 1 is the overall structure diagram of the arrester on-line monitoring device detector described in the utility model. 1—Temperature compensation circuit 2—Nonlinear compensation circuit 3—Standard sine wave signal generator 4—Voltage and current conversion device 5—R232 6—Single chip computer 7—LCD display 8—Keyboard

Detailed ways:

With reference to accompanying drawing 1 now, description is as follows in conjunction with embodiment: The surge arrester on-line monitoring device detection instrument described in the utility model relates to temperature compensation circuit 1, non-linear compensation circuit 2, standard sine wave signal generator 3, voltage-current conversion device 4. Composed of R232 5, single-chip microcomputer 6, liquid crystal display 7 and keyboard 8. The temperature compensation circuit 1 and the nonlinear compensation circuit 2 arranged side by side are respectively connected with the standard sine wave signal generator 3, and the standard sine wave signal generator 3 is connected to the voltage-current conversion device 4 and the single-chip microcomputer 6 at the same time, and the single-chip microcomputer 6 is connected At the same time as R232 5, it is connected to the liquid crystal display 7 and the keyboard 8. The 50Hz standard sine wave signal generator 3 generates a fixed voltage signal, and the voltage-current conversion device 4 converts this voltage signal into the required 0.2mA~10mA current signal. Since the external temperature change will cause the output voltage amplitude to drift, the output voltage of the standard sine wave signal generator 3 at different temperatures is recorded, and the temperature coefficient table is obtained, with 5°C as the step size, according to the temperature collected by the semiconductor temperature sensor Temperature value, add the temperature system to the standard sine wave signal generator 3. Due to the non-linearity of the circuit transmission parameters, the output current signal of 0.2mA~10mA has a certain non-linearity. In order to compensate for this error, the output current is measured with a step size of 0.1mA to measure the current value in the entire range, using the minimum square meter Multiplication and non-linear fitting are performed to obtain a fitting polynomial of degree 5, and this fitting coefficient is compensated into the standard sine wave signal generator 3 circuit. After temperature compensation and non-linear compensation processing, the linearity and stability of the current generator circuit in the voltage-current conversion device 4 will be greatly improved, fully meeting the test requirements of the system. In order to obtain maximum current amplitude and waveform steepness, the inductance of the discharge loop must be minimized. Therefore, when designing an inrush current device, its rationality should be fully considered in terms of the structure of the device and the choice of components.

Capacitive energy storage: Energy storage in the charging circuit is an important part of the inrush current device. It is impossible to directly obtain a strong inrush current with a certain waveform from the grid. Generally, the energy is stored in a longer period of time by means of an energy storage system. Store it for a long time, and then release it instantaneously to obtain a strong shock current. There are many ways to store energy, such as capacitive energy storage, inductive energy storage, mechanical energy storage, battery energy storage, etc. Among them, capacitive energy storage is the most widely used and the technology is mature. In the impulse current device scheme, we adopt the capacitive energy storage method. Based on the principle of reducing inductance, we choose low inductance pulse capacitors. When wiring, keep the wires as short as possible, and the wires with the same direction of current as far away as possible to make the mutual inductance as small as possible; while the wires with different current directions are as close as possible to make the mutual inductance as large as possible. According to the calculation of the energy calculation formula W=1/2CU ² of the capacitor, it is concluded that the value of the capacitor is about 20μF, and when the charging voltage of the capacitor is 700-800V, through the triggering of the gap, a waveform of 8/20μs and a current amplitude of 100A can be obtained. Inrush current output.

Wave modulation resistor: In the impulse current device, the function of the wave modulation resistor is to adjust the output waveform parameters of the impulse current. In order to make the loop generate as large an inrush current as possible, the equivalent inductance of the loop is required to be as small as possible, which brings certain difficulties to the design of the modulating resistor. On the one hand, the equivalent inductance of the modulating resistor is required to be as small as possible. The shock current wave of the duration, the wave-modulating resistor must have an appropriate resistance value. The equivalent resistance and equivalent inductance of the modulating resistor are a pair of contradictory parameters. When the resistance value is large, the corresponding inductance must also be large. Therefore, when we choose to make wave-modulating resistors, manganese-copper wire, an alloy material with high resistivity and good stability, is the first choice. In the winding manufacturing process, we adopted the S-fold method, which automatically offsets the inductance of the resistor through the direction of the current in and out, and obtained a satisfactory effect.

As the single-chip microcomputer 6 in the whole machine, it is the control core of the system, and mainly completes the man-machine interface function and the data interface function. The human-machine interface function is composed of a liquid crystal display 7 and a keyboard 8. The user sets parameters through keys, and the system displays parameters and test results through the liquid crystal display 7. The data interface communicates with the host computer through R2325, and uploads the measurement data to the host computer. The detection instrument for the on-line monitoring device of the arrester described in the utility model has the advantages of simple overall structure, convenient operation and use, good stability and high reliability, and can perform on-site detection on the on-line monitoring device of the zinc oxide arrester. After starting up, the instrument automatically performs current calibration. After the current verification is completed, the counter operation check is automatically performed.

Claims (1)

1. The lightning arrester online monitoring device detector is characterized in that the temperature compensation circuit (1) and the nonlinear compensation circuit (2) are arranged in parallel, respectively connected to the standard sine wave signal generator (3), and the standard sine wave signal generator (3) is connected to the voltage-current conversion device (4) and the single-chip microcomputer (6) at the same time, and the single-chip microcomputer (6) is connected to the liquid crystal display (7) and the keyboard (8) while being connected to the R232 (5).