CN107356833B - Control measurement circuit of power frequency follow current test device - Google Patents
Control measurement circuit of power frequency follow current test device Download PDFInfo
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Abstract
The invention provides a control measurement circuit of a power frequency follow current test device, and belongs to the field of control measurement of power equipment. The control measurement circuit includes: the system comprises a primary side measuring circuit, a signal conditioning circuit, a control circuit and a controller; the primary side measuring circuit is used for collecting measuring signals from the primary side circuit and transmitting the measuring signals to the signal conditioning circuit; the signal conditioning circuit is used for performing signal conditioning and digital-to-analog conversion on the measurement signals and transmitting the converted measurement signals to the controller; the controller is used for outputting a control signal to the control circuit according to the converted measurement signal, and the control circuit triggers a surge voltage generator in the primary side circuit to generate surge overvoltage; the control circuit, the signal conditioning circuit and the controller are powered by one path of voltage respectively, and all paths of voltages are mutually isolated. The invention can effectively prevent the damage of the impulse overvoltage generated by the impulse voltage generator in the primary side circuit to the control measuring circuit of the power frequency flywheel test device.
Description
Technical Field
The invention relates to the field of control and measurement of power equipment, in particular to a control and measurement circuit of a power frequency follow current test device.
Background
The electric lightning arrester is widely applied to power supply and railway power systems and is used for guiding lightning current to the ground so as to inhibit the influence of lightning wave overvoltage on power users. The current common electric lightning arrester is a zinc oxide lightning arrester. The quality of the electric power arrester directly influences the lightning protection performance of the electric power system, so that experimental research on the current recovery characteristic of the zinc oxide arrester under the action of lightning waves is carried out, namely, the industrial frequency follow current test of the arrester is carried out, and the electric power arrester has very important engineering practical value.
The industrial frequency follow current test of the lightning arrester needs to realize industrial frequency and impact combined pressurization, and compared with an independent industrial frequency and impact voltage generator, the industrial frequency follow current test device requires that the impact overvoltage can be overlapped at any point of the industrial frequency alternating voltage, and has higher requirements on control precision. Meanwhile, as the amplitude of the impulse voltage is high and the steepness is high, the impulse overvoltage is overlapped on the power frequency power supply, and the power frequency voltage supply can be damaged. Therefore, the reliability and stability requirements of the power frequency follow current test device are higher.
In the related art, a control measurement circuit of a power frequency follow current test device is provided, and a power frequency power supply generates power frequency voltage by adopting an RLC oscillation loop. Such a power frequency freewheel test device often can not necessarily produce resonance in the test, and the oscillation frequency is not necessarily 50Hz power frequency, leads to the randomness of this kind of power frequency freewheel test very big. In addition, according to IEC (International Electro technical Commission ) standards, most of the existing industrial frequency flywheel test devices use a power grid connected test transformer to generate industrial frequency voltage, a surge voltage generator generates surge overvoltage, and a surge gap is adopted between an industrial frequency power supply and a surge power supply for isolation. When the power frequency freewheel test device is used for testing, the control circuit, the measuring circuit and the power supply are overlapped with the alternating current power supply due to the impact overvoltage, so that the control measuring equipment of the power frequency freewheel test device is likely to be damaged greatly.
Disclosure of Invention
The present invention provides a control measurement circuit for a power frequency freewheel test device that overcomes or at least partially solves the above-mentioned problems.
The control measurement circuit of the power frequency follow current test device comprises: the system comprises a primary measurement circuit, a signal conditioning circuit, a control circuit and a controller;
the primary side measuring circuit is used for collecting measuring signals from the primary side circuit and transmitting the measuring signals to the signal conditioning circuit; the signal conditioning circuit is used for performing signal conditioning and digital-to-analog conversion on the measurement signals and transmitting the converted measurement signals to the controller; the controller is used for outputting a control signal to the control circuit according to the converted measurement signal, and the control circuit triggers the impulse voltage generator in the primary side circuit to generate impulse overvoltage; the control circuit, the signal conditioning circuit and the controller are powered by one path of voltage respectively, and all paths of voltages are mutually isolated.
The control measurement circuit further comprises a first photoelectric isolation module; the primary side measuring circuit is used for transmitting the measuring signal to the first photoelectric isolation module, and the first photoelectric isolation module is used for carrying out photoelectric isolation on the measuring signal and transmitting the measuring signal after photoelectric isolation to the signal conditioning circuit.
The control measurement circuit further comprises a second photoelectric isolation module; the control circuit is used for outputting a control signal to the second photoelectric isolation module according to the converted measurement signal; the second photoelectric isolation module is used for performing photoelectric isolation on the control signal and outputting the control signal subjected to photoelectric isolation to the control circuit.
The measuring signals comprise power frequency voltage signals, voltage signals at two ends of the sample and current signals flowing through the sample; the primary side measuring circuit comprises a resistor-capacitor voltage divider, a capacitive voltage divider and a rogowski coil, wherein the resistor-capacitor voltage divider is used for measuring power frequency voltage signals, the capacitive voltage divider is used for measuring voltage signals at two ends of a sample, and the rogowski coil is used for measuring current flowing through the sample.
The control circuit, the signal conditioning circuit and the controller are powered by a preset power supply; the preset power supply is connected with the isolation transformer, and outputs multiple paths of voltages to the control circuit, the signal conditioning circuit and the controller through the isolation transformer, wherein the control circuit, the signal conditioning circuit and the controller respectively correspond to one path of voltage.
Wherein the preset power supply is an uninterruptible power supply.
The primary side circuit comprises a power frequency alternating current voltage source and a surge voltage generator; the power frequency alternating current voltage source, the tested article and the impulse voltage generator are connected in parallel.
The power frequency alternating current voltage source comprises a voltage regulator and a test transformer; the voltage regulator is connected in parallel with the test transformer.
The beneficial effects that this application provided technical scheme brought are:
firstly, through isolating each branch voltage corresponding to the control circuit, the signal conditioning circuit and the controller, the damage to the control circuit caused by the overvoltage generated by the impulse voltage generator in the primary side circuit can be effectively prevented, and the damage to the control measuring equipment of the power frequency follow current test device can be effectively prevented.
And secondly, the power frequency power supply and the impulse power supply can be controlled to jointly pressurize, and the outlet voltage of the test transformer and the voltage and current applied to the test sample are measured, so that the capability of extinguishing the power frequency arc of the lightning arrester equipment under the action of lightning waves is evaluated.
In addition, the primary side measuring circuit adopts a voltage divider to measure the power frequency voltage and the voltages at two ends of the tested product; the current flowing through the test article is measured using a rogowski coil. The voltage and current signals obtained by measuring the voltage divider and the rogowski coil are transmitted to the signal conditioning and A/D conversion circuit after being subjected to photoelectric isolation, and the voltage and current signals are converted into digital quantities and transmitted to the controller, so that the measured distortion caused by the electromagnetic interference problem can be effectively prevented.
Finally, the triggering conduction time of the impulse voltage generator can be calculated according to the measured power frequency voltage signal and the conduction phase angle input by the user, and the relay triggers the impulse voltage generator to conduct, so that the impulse and the power frequency voltage are overlapped at any phase, and further the combined pressurization is realized.
Drawings
FIG. 1 is a schematic diagram of a control measurement circuit of a power frequency flywheel test device according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a signal conditioning circuit according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a control circuit according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a primary side measurement circuit according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a power supply according to an embodiment of the present invention;
FIG. 6 is a flow chart of a synchronous trigger algorithm according to an embodiment of the present invention;
fig. 7 is a schematic diagram of a primary-side circuit according to an embodiment of the invention.
Detailed Description
The following describes in further detail the embodiments of the present invention with reference to the drawings and examples. The following examples are illustrative of the invention and are not intended to limit the scope of the invention.
In a specific embodiment, the invention is further described with reference to the accompanying drawings. Referring to fig. 1, fig. 1 shows a control measurement circuit of a power frequency flywheel test device, where the control measurement circuit includes: a primary side measurement circuit 101, a signal conditioning circuit 102, a control circuit 103, and a controller 104.
The primary side measuring circuit 101 is used for collecting a measuring signal from the primary side circuit and transmitting the measuring signal to the signal conditioning circuit 102; the signal conditioning circuit 102 is configured to perform signal conditioning and digital-to-analog conversion on the measurement signal, and transmit the converted measurement signal to the controller 104; the controller 104 is configured to output a control signal to the control circuit 103 according to the converted measurement signal, and the control circuit 103 triggers a surge voltage generator in the primary side circuit to generate a surge overvoltage; the control circuit 103, the signal conditioning circuit 102 and the controller are respectively powered by one voltage, and the voltages of the two paths are mutually isolated.
After the measurement signal transmitted by the primary side measurement circuit 101 is transmitted to the signal conditioning circuit 102 through an optical fiber, the signal conditioning circuit 102 can convert the received optical signal into an electrical signal on the secondary side, and after the signal conditioning processes such as operational amplification and level conditioning, the electrical signal can be transmitted to an a/D (analog to digital) conversion circuit, and after the a/D conversion circuit converts the analog signal into a digital signal, the digital signal can be transmitted to a control circuit on the computer side for processing. The signal conditioning circuit 102 is a secondary side signal conditioning circuit, and fig. 2 is a schematic diagram of the structure of the signal conditioning circuit 102.
According to the control and measurement circuit of the power frequency follow current test device, provided by the embodiment of the invention, the control circuit 103, the signal conditioning circuit 102 and the controller 104 are mutually isolated from each other according to the voltage of each branch, so that the damage to the control circuit 103 caused by the overvoltage generated by the surge voltage generator in the primary side circuit can be effectively prevented, and the damage to the control and measurement equipment of the power frequency follow current test device can be effectively prevented.
As an alternative embodiment, the control measurement circuit further comprises a first opto-isolator module 105; the primary side measurement circuit 101 is configured to transmit a measurement signal to the first photoelectric isolation module 105, where the first photoelectric isolation module 105 is configured to perform photoelectric isolation on the measurement signal, and transmit the measurement signal after photoelectric isolation to the signal conditioning circuit 102.
The photoelectric isolation module is a new device formed by a semiconductor sensitive device and a light-emitting diode. Its main function is to realize insulation isolation during transmission, input and output of electric signals. In addition, when the signal is transmitted in one direction, no feedback influence can be realized through the photoelectric isolation module, and the signal has the characteristics of strong anti-interference performance, high response speed and the like. In operation, the opto-isolator module typically applies an input signal to the input terminal to cause the light emitting tube to emit light. The photosensitive device outputs photocurrent under magneto-optical radiation, thereby realizing the twice conversion of the photosites.
The first photoelectric conversion module 105 is used for carrying out photoelectric isolation on the measurement signals, so that the output end of the primary side measurement circuit 101 and the input end of the signal conditioning circuit 102 are electrically isolated, namely, the output measurement signals have no influence on the input end of the signal conditioning circuit 102, the anti-interference capability of the measurement signals is enhanced, and the transmission efficiency of the measurement signals is improved.
As an alternative embodiment, the control measurement circuit further comprises a second opto-isolator module 106; the control circuit 103 is configured to output a control signal to the second optoelectronic isolation module 106 according to the converted measurement signal; the second photoelectric isolation module 106 is configured to perform photoelectric isolation on the control signal, and output the control signal after photoelectric isolation to the control circuit 103.
The second photoelectric conversion module 106 is used for photoelectrically isolating the control signal, so that the output end of the control circuit 103 and the input end of the controller 104 are electrically isolated, that is, the output control signal has no influence on the input end of the controller 104, the anti-interference capability of the measurement signal is enhanced, and the transmission efficiency of the control signal is improved.
In addition, after the control signal is transmitted to the second photoelectric isolation module 106 through the data line transmission mode, photoelectric isolation can be performed. The photoelectrically isolated control signals may be transmitted to the controller 104 through an optical fiber. After receiving the control signal, the controller 104 can generate a corresponding control level according to the instruction of the computer end, so as to control the impulse capacitor of the impulse voltage generator to charge or trigger discharging, so as to generate impulse overvoltage. The structure of the control circuit 103 may be as shown in fig. 3.
As an alternative embodiment, the measuring signals comprise power frequency voltage signals, voltage signals at two ends of the sample and current signals flowing through the sample; the primary side measurement circuit 101 includes a resistor-capacitor voltage divider, a capacitive voltage divider, and a rogowski coil, where the resistor-capacitor voltage divider is used to measure a power frequency voltage signal, the capacitive voltage divider is used to measure a voltage signal across a tested object, and the rogowski coil is used to measure a current flowing through the tested object.
Specifically, the voltage signal V1 across the test article can be measured by a pulse capacitance divider in the primary side measurement circuit 101. The power frequency voltage signal V2 can be measured by a resistor-capacitor voltage divider in the primary side measurement circuit 101. The current signal i flowing through the test object can be measured by the rogowski coil in the primary side measurement circuit 101. After the power frequency voltage signal V2, the voltage signal V1 at two ends of the tested article and the current signal i flowing through the tested article are measured, the three signals may be used as measurement signals, and the measurement signals may be transmitted to the signal conditioning circuit 102 through the first photoelectric conversion module 105 in an optical signal manner, which is not limited in particular in the embodiment of the present invention. As shown in fig. 4, the first left diagram in fig. 4 is a schematic diagram of the structure of the rogowski coil, the middle diagram in fig. 4 is a schematic diagram of the structure of the pulse capacitive voltage divider, and the right diagram in fig. 4 is a schematic diagram of the structure of the resistor-capacitor voltage divider.
As an alternative embodiment, the control circuit 103, the signal conditioning circuit 102 and the controller 104 are powered by a preset power supply; the preset power supply is connected with an isolation transformer, and outputs multiple paths of voltages to the control circuit 103, the signal conditioning circuit 102 and the controller 104 through the isolation transformer, wherein the control circuit 103, the signal conditioning circuit 102 and the controller 104 respectively correspond to one path of voltage.
Specifically, the preset power source may be located at the secondary side, that is, the secondary power source in fig. 1. The control circuit 103, the primary side measurement circuit 101 and the controller 104 are isolated from the primary side power grid power supply by a preset power supply. The preset power supply outputs 220V alternating voltage and is connected with the isolation transformer. The primary winding and each secondary winding of the isolation transformer are isolated from each other. The preset power supply can output multiple paths of power supplies after passing through the secondary winding of the isolation transformer, so as to respectively provide one path of voltage for the control circuit 103, the primary side measurement circuit 101 and the controller 104. Specifically, the multiple power supplies of the preset power supply output may include: an analog signal conditioning circuit alternating current power supply; an A/D sampling circuit power supply; a computer power supply; a PLC (Programmable Logic Controller ) controller power supply; the impulse voltage generator controls the power supply and the impulse voltage generator operates the power supply. The structure of the preset power supply can be shown in fig. 5.
As an alternative embodiment, the preset power source is an uninterruptible power source.
The analog signal conditioning circuit power supply, the A/D sampling circuit power supply and the computer power supply are grounded together, and the ground potentials among the three power supplies are connected through magnetic beads. The PLC controller power supply is connected with the impulse voltage generator control power supply ground potential through magnetic beads. Accordingly, the remaining power supplies are isolated from each other. It should be noted that the controller 104 may be the PLC controller, which is not particularly limited in the embodiment of the present invention.
Specifically, the preset power source may be a UPS (Uninterruptible Power System/Uninterruptible Power Supply, uninterrupted) power source, which is not specifically limited in the embodiments of the present invention. For the UPS, the direct-current electric energy can be continuously supplied to the load by the inverter switching mode to ensure that the load keeps normal operation, and the software and the hardware of the load can be protected from damage.
In order to facilitate understanding of the control process of the surge overvoltage, a synchronous triggering method of the power frequency freewheel device provided by the embodiment of the invention is described. The algorithm may be preconfigured on the computer side, which is not particularly limited in the embodiment of the present invention. Specifically, the input quantity of the synchronous triggering algorithm is power frequency voltage, impulse voltage amplitude and triggering phase angle. The amplitude and the current phase angle of the power frequency voltage are obtained through calculation, and when the current phase angle of the power frequency voltage reaches the trigger phase angle, an instruction is sent to the controller 104 to control the impulse voltage generator to trigger generation of impulse overvoltage. The impulse voltage amplitude signal is input to a processor at the computer end by a user, and the processor at the computer end controls the charging time of the capacitor of the impulse voltage generator and the distance between the impulse balls, so as to control the impulse voltage amplitude. The control process of the synchronous triggering algorithm can refer to fig. 6.
As an alternative embodiment, the primary side circuit includes a power frequency ac voltage source and a surge voltage generator; the power frequency alternating current voltage source, the tested article and the impulse voltage generator are connected in parallel.
As an alternative embodiment, the power frequency ac voltage source includes a voltage regulator and a test transformer; the voltage regulator is connected in parallel with the test transformer.
Specifically, as shown in fig. 7. In fig. 7, a dashed box 1 represents a mains frequency AC voltage source, which is input by a mains voltage AC, connected to a voltage regulator and to a test transformer T. Wherein, the test transformer outputs 50Hz power frequency voltage. The dashed box 2 shows a surge voltage generator, when the trigger gap breaks down, the charge capacitor discharges the load to generate a surge voltage. The dashed box 3 represents the tested article, wherein S1 represents the serial gap of the tested article, and RT1 represents the zinc oxide resistance of the tested article; s2, an isolation ball gap between an impulse voltage source and a power frequency power supply is shown; RT2 represents a transformer outlet protection lightning arrester, and L and R respectively represent a protection inductance and a protection resistance for protecting the test transformer from damage. V1 and V2 represent the voltage on the sample and the voltage at the output port of the transformer, respectively, i represents the current flowing through the sample, V1, V2 and i belong to the measured, and are transmitted as measurement signals to the measurement circuit 102.
The embodiment of the invention can control the combined pressurization of the power frequency power supply and the impulse power supply, and measure the outlet voltage of the test transformer and the voltage and current applied to the test sample, thereby evaluating the capability of extinguishing the power frequency arc of the lightning arrester equipment under the action of lightning waves.
The primary side measuring circuit 101 provided by the embodiment of the invention adopts a voltage divider to measure the power frequency voltage and the voltages at two ends of a sample; the current flowing through the sample was measured using a rogowski coil. The voltage and current signals measured by the voltage divider and the rogowski coil are transmitted to a signal conditioning and A/D conversion circuit after being subjected to photoelectric isolation, and the voltage and current signals are converted into digital quantities and then transmitted to the controller 104. The control measurement circuit provided by the embodiment of the invention can effectively prevent the measured distortion caused by the electromagnetic interference problem.
According to the power frequency voltage signal obtained through measurement and the conduction phase angle input by a user, the control circuit 103 calculates the triggering conduction time of the impulse voltage generator, and the relay triggers the impulse voltage generator to conduct, so that the impulse and the power frequency voltage are overlapped in any phase, and further combined pressurization is realized.
The power supply part of the invention adopts UPS power supply to supply power independently, the power supplies of the control circuit 103, the primary side measuring circuit 101 and the controller 104 are isolated from each other, and the damage to the control circuit 103 and the primary side measuring circuit 101 caused by the surge overvoltage generated by the surge voltage generator can be effectively prevented.
Finally, the methods of the present application are only preferred embodiments and are not intended to limit the scope of the invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
1. The utility model provides a control measurement circuit of power frequency freewheel test device which characterized in that includes: the system comprises a primary side measuring circuit, a signal conditioning circuit, a control circuit and a controller;
the primary side measuring circuit is used for collecting measuring signals from the primary side circuit and transmitting the measuring signals to the signal conditioning circuit; the signal conditioning circuit is used for performing signal conditioning and digital-to-analog conversion on the measurement signals and transmitting the converted measurement signals to the controller; the controller is used for outputting a control signal to the control circuit according to the converted measurement signal, and the control circuit triggers a surge voltage generator in the primary side circuit to generate surge overvoltage; the control circuit, the signal conditioning circuit and the controller are powered by one path of voltage respectively, and all paths of voltages are mutually isolated;
the control measurement circuit further comprises a first photoelectric isolation module; the primary side measuring circuit is used for transmitting the measuring signal to the first photoelectric isolation module, and the first photoelectric isolation module is used for carrying out photoelectric isolation on the measuring signal and transmitting the measuring signal after photoelectric isolation to the signal conditioning circuit;
the control measurement circuit further comprises a second photoelectric isolation module; the control circuit is used for outputting a control signal to the second photoelectric isolation module according to the converted measurement signal; the second photoelectric isolation module is used for performing photoelectric isolation on the control signal and outputting the control signal subjected to photoelectric isolation to the control circuit.
2. The control measurement circuit of claim 1, wherein the measurement signal comprises a power frequency voltage signal, a voltage signal across the sample, and a current signal through the sample; the primary side measuring circuit comprises a resistor-capacitor voltage divider, a capacitor voltage divider and a rogowski coil, wherein the resistor-capacitor voltage divider is used for measuring the power frequency voltage signal, the capacitor voltage divider is used for measuring voltage signals at two ends of a tested article, and the rogowski coil is used for measuring current flowing through the tested article.
3. The control and measurement circuit of claim 1, wherein the control circuit, the signal conditioning circuit, and the controller are powered by a preset power source; the preset power supply is connected with an isolation transformer, multiple paths of voltages are output to the control circuit, the signal conditioning circuit and the controller through the isolation transformer, and the control circuit, the signal conditioning circuit and the controller correspond to one path of voltage respectively.
4. A control and measurement circuit according to claim 3, wherein the predetermined power source is an uninterruptible power source.
5. The control and measurement circuit of claim 2, wherein the primary side circuit comprises a power frequency ac voltage source and a surge voltage generator; the power frequency alternating current voltage source, the tested article and the impulse voltage generator are connected in parallel.
6. The control and measurement circuit of claim 5, wherein the power frequency ac voltage source comprises a voltage regulator and a test transformer; the voltage regulator is connected in parallel with the test transformer.
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| CN201352251Y (en) * | 2009-01-21 | 2009-11-25 | 许继集团有限公司 | Impact test device of high voltage direct current (HVDC) power transmission converter valve |
| CN102544842A (en) * | 2010-12-13 | 2012-07-04 | 徐新东 | Socket with improved impact resistance and insulating property |
| CN202041584U (en) * | 2011-01-10 | 2011-11-16 | 西安交通大学 | Measuring device for impulse grounding resistance of movable tower |
| CN104267277B (en) * | 2014-09-23 | 2015-07-22 | 广东电网有限责任公司佛山供电局 | Overvoltage protective performance testing device for overvoltage protective device and control method and system |
| CN104237831B (en) * | 2014-10-13 | 2017-08-22 | 国家电网公司 | A kind of counter of lightning arrester tester calibration device |
| CN106054006B (en) * | 2016-08-08 | 2019-04-05 | 国网湖南省电力公司 | The low pressure starting the arc and the adjustable power frequency continued flow experimental rig of clearance distance and test method |
| CN106646307A (en) * | 2016-10-14 | 2017-05-10 | 国家电网公司 | Lightning arrester counter calibration device |
| CN207366648U (en) * | 2017-07-19 | 2018-05-15 | 国网湖南省电力公司 | A kind of control measuring circuit of power frequency continued flow experimental rig |
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