CN113295964B - Power supply circuit for cable comprehensive test - Google Patents
Power supply circuit for cable comprehensive test Download PDFInfo
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- CN113295964B CN113295964B CN202110560325.5A CN202110560325A CN113295964B CN 113295964 B CN113295964 B CN 113295964B CN 202110560325 A CN202110560325 A CN 202110560325A CN 113295964 B CN113295964 B CN 113295964B
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- 238000012360 testing method Methods 0.000 title claims abstract description 63
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- 239000004065 semiconductor Substances 0.000 claims abstract description 56
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 42
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 42
- 239000010703 silicon Substances 0.000 claims abstract description 42
- 230000008878 coupling Effects 0.000 claims abstract description 40
- 238000010168 coupling process Methods 0.000 claims abstract description 40
- 238000005859 coupling reaction Methods 0.000 claims abstract description 40
- 238000005259 measurement Methods 0.000 claims description 16
- 238000004891 communication Methods 0.000 claims description 10
- 238000011016 integrity testing Methods 0.000 claims description 3
- 238000001514 detection method Methods 0.000 abstract description 9
- 230000010354 integration Effects 0.000 abstract description 8
- 238000010586 diagram Methods 0.000 description 13
- 238000000034 method Methods 0.000 description 10
- 230000008569 process Effects 0.000 description 5
- 230000003287 optical effect Effects 0.000 description 4
- 238000005070 sampling Methods 0.000 description 4
- 230000002457 bidirectional effect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 238000004146 energy storage Methods 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 230000003139 buffering effect Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/083—Locating faults in cables, transmission lines, or networks according to type of conductors in cables, e.g. underground
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R1/00—Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00
- G01R1/28—Provision in measuring instruments for reference values, e.g. standard voltage, standard waveform
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
- G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant
- G01R27/26—Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
- G01R27/2688—Measuring quality factor or dielectric loss, e.g. loss angle, or power factor
- G01R27/2694—Measuring dielectric loss, e.g. loss angle, loss factor or power factor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
- G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
- G01R31/58—Testing of lines, cables or conductors
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
The application discloses a power supply circuit for cable combined test includes: the negative polarity high-voltage power supply circuit comprises a first adjustable high-frequency alternating-current power supply, a first high-frequency high-voltage transformer, a first resistor group, a first capacitor group, a first light-operated semiconductor switch group and a first high-voltage silicon stack group; the positive polarity high-voltage power supply circuit comprises a second adjustable high-frequency alternating-current power supply, a second high-frequency high-voltage transformer, a second resistor group, a second capacitor group, a second light-operated semiconductor switch group and a second high-voltage silicon stack group; the voltage division coupling unit comprises a third resistor group and a third capacitor group; the dielectric loss measuring unit comprises a voltage dividing resistor group, a current transformer, a collecting card and an industrial personal computer; the current transformer is electrically connected with one end of the cable to be tested. The application can solve the technical problems that the mechanical switch in the existing topological circuit is high in reversing noise, poor in high-voltage resistance and low in circuit integration level, actual operation efficiency is poor, and comprehensive requirements of multiple state detection cannot be met.
Description
Technical Field
The application relates to the technical field of cable state detection, in particular to a power supply circuit for a cable comprehensive test.
Background
In recent years, distribution cables and related equipment are gradually popularized and widely applied to distribution networks, but the faults of the distribution cables occur frequently, and the power supply reliability is seriously influenced. At the present stage, no convenient, reliable and economic state detection means is provided for the distribution cable. At present, tests of the distribution cable mainly comprise a voltage withstanding test, a partial discharge test and a dielectric loss test, each test corresponds to a professional device, the integration level is not high, the time consumption of the field tests in sequence is long, and the operation is inconvenient.
Usually, a damped oscillatory wave power supply is mostly used for a field partial discharge test and cannot meet the requirements of a voltage-resistant and dielectric loss test; the ultra-low frequency sine wave high-voltage power supply can be used for field voltage resistance and dielectric loss tests, and can not meet the field partial discharge test requirement due to the equivalence problem.
Most of the existing topological circuits for generating the ultralow frequency cosine square-wave power supply adopt mechanical switches, and the power supply commutation noise under the control of the mechanical switches is high, so that the good dielectric loss detection of partial discharge signals can be influenced; moreover, the power supply reversing switch needs to bear higher voltage in the reversing process, so that certain circuit risk exists; in addition, the current topological circuit cannot simultaneously meet the comprehensive requirement of detecting multiple states of the cable because of low integration level.
Disclosure of Invention
The application provides a power supply circuit for cable combined test for it is big to solve the mechanical switch switching-over noise among the current topological circuit, and high voltage resistance can be relatively poor, and circuit integration is lower, leads to actual operating efficiency relatively poor, and can't satisfy the technical problem of the comprehensive demand that multiple state detected.
In view of the above, the first aspect of the present application provides a power circuit for cable integrity test, including: the device comprises a negative polarity high-voltage power supply circuit, a positive polarity high-voltage power supply circuit, a voltage division coupling unit, a cable to be tested and a dielectric loss measurement unit;
the negative polarity high-voltage power supply circuit comprises a first adjustable high-frequency alternating-current power supply, a first high-frequency high-voltage transformer, a first resistor group, a first capacitor group, a first light-operated semiconductor switch group and a first high-voltage silicon stack group;
the positive polarity high-voltage power supply circuit comprises a second adjustable high-frequency alternating-current power supply, a second high-frequency high-voltage transformer, a second resistor group, a second capacitor group, a second light-operated semiconductor switch group and a second high-voltage silicon stack group;
the voltage division coupling unit comprises a third resistor group and a third capacitor group;
the dielectric loss measuring unit comprises a voltage dividing resistor group, a current transformer, a collecting card and an industrial personal computer;
and the current transformer is electrically connected with one end of the cable to be tested.
Optionally, the negative polarity high voltage power supply circuit and the positive polarity high voltage power supply circuit have the same circuit connection structure and are connected in parallel.
Optionally, the method further includes: a high voltage inductor;
the high-voltage inductor is connected between the negative polarity high-voltage power supply circuit and the voltage division coupling unit.
Optionally, the first optical control semiconductor switch group includes a first optical control semiconductor switch and a second optical control semiconductor switch;
the second light-operated semiconductor switch group comprises a third light-operated semiconductor switch and a fourth light-operated semiconductor switch;
the first high-voltage silicon stack group comprises a first high-voltage silicon stack and a second high-voltage silicon stack;
the second high-voltage silicon stack group comprises a third high-voltage silicon stack and a fourth high-voltage silicon stack.
Optionally, the first resistor group includes a first resistor and a second resistor;
the second resistor group comprises a third resistor and a fourth resistor;
the third resistor group comprises a fifth resistor and a sixth resistor;
the voltage division resistor group comprises a seventh resistor and an eighth resistor.
Optionally, the first capacitor bank includes a first capacitor and a second capacitor;
the second capacitor bank comprises a third capacitor and a fourth capacitor;
the third capacitor bank includes a fifth capacitor and a sixth capacitor.
Optionally, one end of the fifth resistor is connected to one end of the sixth resistor;
one end of the fifth capacitor is connected with one end of the sixth capacitor;
the other end of the fifth resistor and the other end of the fifth capacitor are both connected with the voltage dividing resistor group;
the other end of the sixth resistor and the other end of the sixth capacitor are both connected with the PD coupling unit.
Optionally, the seventh resistor and the eighth resistor in the voltage dividing resistor group are connected in series, and one end of the eighth resistor is grounded.
Optionally, the current transformer and the voltage dividing resistor group are both connected with the input end of the acquisition card;
and the output end of the acquisition card is connected with the input end of the industrial personal computer.
Optionally, the dielectric loss measurement unit further includes: a communication module;
the communication module is connected with the industrial personal computer and used for communicating the industrial personal computer with the upper computer.
According to the technical scheme, the embodiment of the application has the following advantages:
in this application, a power supply circuit for cable combined test is provided, include: the device comprises a negative polarity high-voltage power supply circuit, a positive polarity high-voltage power supply circuit, a voltage division coupling unit, a cable to be tested and a dielectric loss measurement unit; the negative polarity high-voltage power supply circuit comprises a first adjustable high-frequency alternating-current power supply, a first high-frequency high-voltage transformer, a first resistor group, a first capacitor group, a first light-operated semiconductor switch group and a first high-voltage silicon stack group; the positive polarity high-voltage power supply circuit comprises a second adjustable high-frequency alternating-current power supply, a second high-frequency high-voltage transformer, a second resistor group, a second capacitor group, a second light-operated semiconductor switch group and a second high-voltage silicon stack group; the voltage division coupling unit comprises a third resistor group and a third capacitor group; the dielectric loss measuring unit comprises a voltage dividing resistor group, a current transformer, a collecting card and an industrial personal computer; the current transformer is electrically connected with one end of the cable to be tested.
According to the power supply circuit for the cable comprehensive test, the ultralow-frequency cosine square-wave power supply is formed by the negative-polarity high-voltage power supply circuit and the positive-polarity high-voltage power supply circuit to provide the voltage required in the test process; the light-operated semiconductor switch group is selected in the power circuit to realize power supply commutation, the light-operated semiconductor switch takes laser beams as switching-on signals, high voltage and low voltage are completely isolated, and the insulating property is excellent; the bidirectional voltage resistance of the light-operated semiconductor switch before being switched on is good; the high-voltage testing device has no noise when being switched on, and can meet the detection requirements of partial discharge signals and dielectric loss in high-voltage testing; the partial discharge test and the dielectric loss test can be realized through the partial pressure coupling unit and the dielectric loss measurement unit, and the integrated circuit design integration level is high. Therefore, the technical problems that the mechanical switch in the existing topological circuit is high in reversing noise, poor in high-voltage resistance and low in circuit integration level, actual operation efficiency is poor, and comprehensive requirements of multiple state detection cannot be met can be solved.
Drawings
Fig. 1 is a schematic diagram of a topology of a power circuit for cable integrity test according to an embodiment of the present disclosure;
FIG. 2 is a schematic diagram illustrating operation of a negative power supply commutation circuit according to an embodiment of the present application;
FIG. 3 is a schematic diagram illustrating the operation of a forward power supply commutation circuit according to an embodiment of the present application;
FIG. 4 is a system of components of a power supply circuit for cable integrity testing as provided herein;
FIG. 5 is a schematic diagram of an application of the power supply circuit of the present application;
fig. 6 is a schematic diagram of an operation topology of a voltage withstand test circuit based on a power supply circuit of the present application;
fig. 7 is a diagram of an operation topology of a withstand voltage plus partial discharge test circuit based on a power supply circuit of the present application;
fig. 8 is a diagram of an operation topology of a voltage-withstanding and dielectric loss test circuit based on a power supply circuit of the present application;
fig. 9 is a topology diagram of the operation of the voltage-withstand, partial-discharge and dielectric-loss test circuit based on the power circuit of the present application;
reference numerals are as follows:
a negative polarity high voltage power supply circuit 1; a positive polarity high voltage power supply circuit 2; a voltage division coupling unit 3; a cable 4 to be tested; a dielectric loss measuring unit 5; a forward high-voltage-multiplying and reversing component 6; a negative high voltage doubling and reversing component 7; a high voltage inductive device 8; a high voltage inductive strut 9; a high voltage inductor base 10; a roller 11; a high-pressure equalizing device 12; a resistive-capacitive divider high voltage arm 13; a ground post 14; a low-voltage arm and PD coupling unit 15; a dielectric loss measurement module 16; a compensation capacitor 17; a voltage-withstand, partial-discharge and dielectric loss integrated device 18; a high-voltage lead wire 19; a source terminal partial discharge measurement module 20.
Detailed Description
In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The applicant finds that the ultralow frequency cosine square-wave power supply can theoretically perform the detection of voltage resistance, partial discharge and dielectric loss, the ultralow frequency cosine square-wave power supply can perform the voltage resistance test when the positive voltage or the negative voltage is maintained, and the ultralow frequency cosine square-wave power supply can perform the partial discharge and dielectric loss test when the power supply is commutated.
For ease of understanding, referring to fig. 1, the present application provides an embodiment of a power circuit for cable integrity test, comprising: the device comprises a negative polarity high-voltage power supply circuit 1, a positive polarity high-voltage power supply circuit 2, a voltage division coupling unit 3, a cable to be tested 4 and a dielectric loss measuring unit 5;
the negative polarity high-voltage power supply circuit 1 comprises a first adjustable high-frequency alternating-current power supply S1, a first high-frequency high-voltage transformer T1, a first resistor group, a first capacitor group, a first light-operated semiconductor switch group and a first high-voltage silicon stack group; the positive polarity high voltage power circuit 2 comprises a second adjustable high frequency alternating current power supply S2, a second high frequency high voltage transformer T2, a second resistor group, a second capacitor group, a second photo-controlled semiconductor switch group and a second high voltage silicon stack group. The first adjustable high-frequency alternating current power supply S1 and the second adjustable high-frequency alternating current power supply S2 are the same in specification, the power supply frequency is 10 KHz-100 KHz, and the voltage peak value is not lower than 300V. The first high-frequency high-voltage transformer T1 and the second high-frequency high-voltage transformer T2 are also the same, the working frequency is 10 KHz-100 KHz, and the voltage ratio of the primary side to the secondary side is not less than 1: and 60, the secondary side output has the withstand voltage to the ground of not less than 30 KV. The first resistor group and the second resistor group are used for limiting current and used as protection elements of the high-voltage-multiplying and reversing assembly, and the resistance value of the resistors is not less than 20k omega. The first light-operated semiconductor switch group and the second light-operated semiconductor switch group control the working state of the switching component through the on-off time sequence of the switches. The first high-voltage silicon stack group and the first capacitor group form a negative voltage-multiplying circuit, and the second high-voltage silicon stack group and the second capacitor group form a positive voltage-multiplying circuit.
The voltage division coupling unit 3 includes a third resistor group and a third capacitor group. The voltage division coupling unit 3 is mainly used for collecting power supply voltage and coupling high-frequency partial discharge signals excited by a high-voltage power supply. Therefore, besides the resistor and the capacitor, the device also comprises a PD coupling unit which has partial discharge coupling impedance and is mainly used for coupling high-frequency partial discharge signals, and the PD coupling unit can be controlled by a host computer. Specifically, the third resistor group is used for collecting power supply voltage, and according to a resistor voltage division principle, a certain relation exists between voltage collected by voltage division and the power supply voltage, and the voltage and the power supply voltage can be calculated and expressed according to a circuit principle. And the third capacitor bank is used for coupling high-frequency partial discharge signal acquisition. And the third resistor group and the third capacitor group can be balanced and adjusted to meet the circuit requirement.
The dielectric loss measuring unit 5 comprises a voltage dividing resistor group, a current transformer CT1, an acquisition card and an industrial personal computer; the current transformer CT1 is electrically connected to one end of the cable 4 to be tested. The dielectric loss measurement unit 5 is used for collecting key dielectric loss parameters and analyzing and calculating the key dielectric loss parameters, and the dielectric loss measurement unit 5 is connected with an upper computer through an industrial personal computer and controlled by the upper computer. The voltage resistance group is composed of high-precision resistors and is used for acquiring a precise voltage value applied to a tested cable. The current transformer CT1 is a high-precision current transformer, is electrically connected with the cable 4 to be tested, and is used for obtaining the current value on the cable to be tested. The acquisition card is a dual-channel acquisition card not lower than 100MS/s, and voltage and current signals enter the acquisition card through an amplifying and buffering circuit. The industrial personal computer is used for calculating the dielectric loss value through the dielectric loss key parameters acquired by the acquisition card.
Further, the negative polarity high voltage power supply circuit 1 and the positive polarity high voltage power supply circuit 2 have the same circuit connection structure and are connected in parallel.
Referring to fig. 1, the negative polarity high voltage power circuit 1 and the positive polarity high voltage power circuit 2 are symmetrically distributed, and one end of the first high frequency high voltage transformer T1 and one end of the second high frequency high voltage transformer T2 are grounded.
Further, the method also comprises the following steps: a high-voltage inductor L; the high-voltage inductor L is connected between the negative polarity high-voltage power supply circuit 1 and the voltage division coupling unit 3.
The high-voltage inductor L is used as an energy storage element, and forms an LC loop with the cable 4 to be tested when the power supply is switched, no measurable partial discharge signal is required under the highest working voltage of the equipment, and the value of the inductor is in the range of 0.6-2H.
Further, the first group of the photo-semiconductor switches comprises a first photo-semiconductor switch K1 and a second photo-semiconductor switch K2; the second photo semiconductor switch group includes a third photo semiconductor switch K3 and a fourth photo semiconductor switch K4.
Referring to fig. 1, each of the photo-semiconductor switches includes two switches, and in the two-pole high-voltage power supply circuit, the operation state of the power supply direction is controlled by the first photo-semiconductor switch K1, the second photo-semiconductor switch K2, the third photo-semiconductor switch K3 and the fourth photo-semiconductor switch K4.
The first high-voltage silicon stack group comprises a first high-voltage silicon stack D1 and a second high-voltage silicon stack D2; the second high voltage silicon stack group includes a third high voltage silicon stack D3 and a fourth high voltage silicon stack D4. The two high-voltage silicon stacks are respectively connected with the two light-operated semiconductor switches, and the working state control of the voltage doubling circuit is realized through the on-off of the switches.
Further, the first resistor group comprises a first resistor R1 and a second resistor R2; the second resistor group comprises a third resistor R3 and a fourth resistor R4; the third resistor group comprises a fifth resistor R5 and a sixth resistor R6; the voltage dividing resistor group comprises a seventh resistor R7 and an eighth resistor R8.
Referring to fig. 1, one end of the first resistor R1 and one end of the second resistor R2 are both connected to the first high-frequency high-voltage transformer T1 and are distributed on different sides. One end of the third resistor R3 and one end of the fourth resistor R4 are both connected with the second high-frequency high-voltage transformer T2 and are also distributed on different sides.
Further, the first capacitor bank includes a first capacitor C1 and a second capacitor C2; the second capacitor bank comprises a third capacitor C3 and a fourth capacitor C4; the third capacitance group comprises a fifth capacitance C5 and a sixth capacitance C6.
Referring to fig. 1, the connection relationship of the negative polarity high voltage power circuit 1 is: one end of a first capacitor C1 is connected with the other end of the first resistor R1, and the other end of the first capacitor C1 is connected with one end of the first photo-semiconductor switch K1 and the output end of the second high-voltage silicon stack D2. The other end of the first light-operated semiconductor switch K1 is connected with the input end of a first high-voltage silicon stack D1; the input end of the second high-voltage silicon stack D2 is connected with one end of a second light-operated semiconductor switch K2. The second resistor R2 and the second capacitor C2 are connected in series between the other end of the second photo-semiconductor switch K2 and the output end of the first high-voltage silicon stack D1. The secondary side of the first high-frequency high-voltage transformer T1 is connected between the first resistor R1 and the output end of the first high-voltage silicon stack D1, and the primary side of the first high-frequency high-voltage transformer T1 is connected with a first adjustable high-frequency alternating current power supply S1.
It can be understood that the structure of the positive polarity high voltage power supply circuit 2 is the same as that of the negative polarity high voltage power supply circuit 1, and therefore, the connection relationship between the second adjustable high frequency ac power supply S2, the second high frequency high voltage transformer T2, the resistor in the second resistor group, the capacitor in the second capacitor group, the switch in the second photo-controlled semiconductor switch group, and the second high voltage silicon stack in the second high voltage silicon stack group is similar to that in the negative polarity high voltage power supply circuit 1, except that the connection directions of some devices are different, for example, the connection directions of the third high voltage silicon stack D3 and the fourth high voltage silicon stack D4 are opposite to those of the first high voltage silicon stack D1 and the second high voltage silicon stack D2, so as to meet the positive and negative polarity requirements of the power supply.
The other end of the second photo-semiconductor switch K2 and the other end of the fourth photo-semiconductor switch K4 are connected to one end of a high-voltage inductor L as the output terminal of the power supply circuit. The other end of the high-voltage inductor L is respectively connected with the fifth resistor R5, the fifth capacitor C5, the seventh resistor R7 and the other end of the cable 4 to be tested.
Further, one end of the fifth resistor R5 is connected to one end of the sixth resistor R6; one end of the fifth capacitor C5 is connected with one end of the sixth capacitor C6; the other end of the fifth resistor R5 and the other end of the fifth capacitor C5 are both connected with the voltage dividing resistor group; the other end of the sixth resistor R6 and the other end of the sixth capacitor C6 are both connected with the PD coupling unit. The voltage division coupling unit 3 is used for collecting power voltage and coupling partial discharge signals, the specific third resistor group is a fifth resistor R5 and a sixth resistor R6, and according to the resistor voltage division principle, the voltage and the power voltage collected by voltage division can be expressed as follows according to the formula:
wherein v is Sampling For the voltage acquired, v Power supply Is the supply voltage. The third capacitor bank comprises a fifth capacitor C5 and a sixth capacitor C6, which are two coupling capacitors, and values of the resistors and the capacitors in the voltage division coupling circuit can be obtained through the following formula:
R5×C5＝R6×C6；
the above is the connection relationship and the specific adjustment mechanism of each device of the voltage division coupling circuit.
Further, the seventh resistor R7 in the voltage dividing resistor group is connected in series with the eighth resistor R8, and one end of the eighth resistor R8 is grounded. The voltage dividing resistor group is a device in the dielectric loss measuring unit 5, and a high-precision resistor is selected to be used as the voltage dividing device, so that the voltage on the cable 4 to be measured is accurately obtained.
Furthermore, the current transformer CT1 and the divider resistor group are both connected with the input end of the acquisition card; the output end of the acquisition card is connected with the input end of the industrial personal computer. Referring to fig. 1, an input terminal of the current transformer CT1 is connected to one end of the cable 4 to be tested, an output terminal of the current transformer CT1 is connected to an input terminal of the acquisition card, and the input terminal of the acquisition card is connected to one end of the seventh resistor R7 and the other end of the eighth resistor R8 for obtaining voltage. The industrial personal computer is connected with the output end of the acquisition card through the USB interface, and key parameters are acquired from the industrial personal computer.
Further, the dielectric loss measuring unit 5 further includes: a communication module; the communication module is connected with the industrial personal computer and used for communicating the industrial personal computer with the upper computer. The communication module can be wifi communication mechanism, and the data that the industrial computer acquireed or calculated can be transmitted for the host computer through wifi's form, handles.
When the circuit starts to operate, the power supply works in a voltage-multiplying rectification state by switching the light-operated semiconductor switch of the high-voltage-multiplying and reversing assembly, the high-voltage alternating-current input voltage is adjusted, and the equipment can generate a positive or negative direct-current high-voltage power supply. Because the power cable to be tested is embodied as a capacitive load to the direct current high-voltage power supply, the high-voltage power supply charges the cable 4 to be tested through the high-voltage inductor L at the moment, and the charging is maintained after the charging reaches a preset voltage.
The power supply circuit for the cable comprehensive test provided by the embodiment of the application mainly generates cosine square wave type ultralow frequency voltage. It should be emphasized that when the power supply is commutated, the ac high voltage input needs to be stopped, by controlling the high voltage doubling and the direction of the switch in the commutation component, the high voltage inductor L and the cable 4 to be tested form an LC loop, the commutation of the power supply is realized, and the commutation waveform frequency of the power supply can be calculated by the following formula:
and C is the equivalent capacitance of the cable 4 to be measured.
The operation procedure of generating the target voltage may be divided into the following operations:
1) negative boost
As shown in fig. 2, when the power supply starts to operate, at 0S, the first photo-controlled semiconductor switch K1 and the second photo-controlled semiconductor switch K2 are closed, the third photo-controlled semiconductor switch K3 and the fourth photo-controlled semiconductor switch K4 are opened, the actual execution process may be delayed for a period of time, for example, 20ms, at this time, the high-voltage doubling and reversing component is in a negative power voltage doubling circuit state, the amplitude of the first adjustable high-frequency ac power supply S1 is adjusted, the device may be controlled to output the amplitude of the negative dc high voltage, the negative dc high voltage charges the cable 4 to be tested through the high-voltage inductor L for energy storage, the voltage is maintained after charging to the preset negative dc voltage, the negative dc high voltage maintaining time is determined according to the frequency of the power supply that needs to be generated, a timer may be used for timing, and the negative dc high voltage maintaining time may be calculated according to the following formula:
2) forward power supply commutation
As shown in fig. 3, after the negative voltage dc high voltage holding time is up, the first adjustable high frequency ac power supply S1 is first turned off, then the first photosemiconductor switch K1 and the second photosemiconductor switch K2 are sequentially turned off, the third semiconductor photoswitch K3 and the fourth semiconductor photoswitch K4 are turned on, and at this time, the equivalent capacitor C of the cable 4 to be tested and the high voltage inductor L form an LC oscillating wave loop, so that the direction of the power supply voltage is changed from negative to positive, and the power supply commutation waveform frequency can be calculated by the following formula:
the power supply commutation time is typically 2-6 ms. The field test is used for carrying out partial discharge and dielectric loss measurement when the power supply is commutated, and the switching element involved in commutation is required to have no measurable partial discharge signal under commutation voltage when the power supply is commutated.
3) Forward voltage holding
The power supply is switched to the positive direction and the negative direction, the switching state is kept, the high-voltage doubling and reversing assembly is in the state of a positive power voltage doubling circuit at the moment, the second adjustable high-frequency alternating-current power supply S2 is switched on and adjusted, the amplitude of positive direct-current voltage can be controlled and output, the positive direct-current high voltage is charged and stored for the cable 4 to be tested through the high-voltage inductor L, the voltage is kept after the positive direct-current high voltage is charged to the preset positive direct-current voltage, and the keeping time is the same as the keeping time of the negative direct-current voltage.
4) Negative power supply commutation
As shown in fig. 2, after the forward high voltage holding time is up, the second adjustable high frequency ac power supply S2 is first turned off, then the third photosemiconductor switch K3 and the fourth photosemiconductor switch K4 are turned off in sequence, and the first photosemiconductor switch K1 and the second photosemiconductor switch K2 are turned on, at this time, the equivalent capacitor C of the cable 4 to be tested and the high voltage inductor L form an LC oscillating wave loop, so that the direction of the power supply voltage is changed from the forward direction to the negative direction.
Repeating the above 4 operation processes can generate the cosine square wave type ultralow frequency voltage.
According to the power supply circuit for the cable comprehensive test, the ultralow-frequency cosine square-wave power supply is formed through the negative-polarity high-voltage power supply circuit and the positive-polarity high-voltage power supply circuit to provide voltage required by the test process; the light-operated semiconductor switch group is selected in the power circuit to realize power supply commutation, the light-operated semiconductor switch takes laser beams as switching-on signals, high voltage and low voltage are completely isolated, and the insulating property is excellent; the bidirectional voltage resistance of the light-operated semiconductor switch before being switched on is good; the high-voltage testing device has no noise when being switched on, and can meet the detection requirements of partial discharge signals and dielectric loss in high-voltage testing; the partial discharge test and the dielectric loss test can be realized through the partial pressure coupling unit and the dielectric loss measurement unit, and the integrated circuit design integration level is high. Therefore, the technical problems that the mechanical switch in the existing topological circuit is high in reversing noise, poor in high-voltage resistance and low in circuit integration level, actual operation efficiency is poor, and comprehensive requirements of multiple state detection cannot be met can be solved.
For easy understanding, a component system of a power supply circuit for a cable comprehensive test is provided, and please refer to fig. 4, specifically includes a positive high-voltage-multiplying and reversing component 6, a negative high-voltage-multiplying and reversing component 7, a high-voltage inductor device 8, a high-voltage inductor support 9, a high-voltage inductor base 10, a roller 11, a high-voltage equalizing device 12, a high-voltage arm 13 of a resistance-capacitance voltage divider, a ground post 14, a low-voltage arm and PD coupling unit 15, and a dielectric loss measurement module 16. The specific operation mode is as above, and is not described in detail.
For easy understanding, a field device application case of a power supply for cable integrity test is provided; referring to fig. 5, the device includes a compensation capacitor 17, a voltage-withstanding, partial-discharge and dielectric loss integrated device 18, a high-voltage lead 19, a cable 4 to be tested, and a source partial-discharge measurement module 20. Through the application case, a voltage withstanding test, a voltage withstanding plus partial discharge test, a voltage withstanding plus dielectric loss test and a voltage withstanding and partial discharge plus dielectric loss test can be respectively carried out, and the test circuit diagrams shown in the figures 6 to 9 can be obtained according to different circuit working modes.
Fig. 6 is a voltage withstand test circuit operation topological diagram, the upper computer controls to turn off the PD coupling unit and partial circuit functions of the dielectric loss measurement unit 5, only the voltage sampling circuit composed of the fifth resistor R5 and the sixth resistor R6 normally operates, at this time, the device operates in a voltage withstand mode, and after voltage boosting, a voltage withstand test can be performed on the cable 4 to be tested.
Fig. 7 is a voltage withstand voltage plus partial discharge test circuit operation topological diagram, the upper computer controls to close the dielectric loss measurement unit 5, the fifth resistor R5 and the sixth resistor R6 form a voltage sampling circuit, the fifth capacitor C5, the sixth capacitor C6 and the PD coupling unit form a partial discharge coupling circuit to work, at this time, the device works in a voltage withstand voltage plus partial discharge mode, after voltage boost, not only is the voltage withstand test performed on the cable to be tested, but also partial discharge is measured while voltage withstand, and after the test, a voltage withstand voltage and partial discharge conclusion can be given.
Fig. 8 is a voltage-withstand voltage plus dielectric loss test circuit operation topological diagram, the upper computer controls to close the PD coupling unit, the fifth resistor R5 and the sixth resistor R6 form a voltage sampling circuit, and the dielectric loss measurement unit 5 operates as a circuit, at this time, the device operates in a voltage-withstand voltage plus dielectric loss mode, after voltage boosting, not only the voltage-withstand test is performed on the cable to be measured, but also the dielectric loss value is measured while voltage-withstand, and after the test, a voltage-withstand voltage and dielectric loss conclusion can be given.
Fig. 9 is a voltage-withstand, partial-discharge and dielectric-loss integrated test circuit operation topological diagram, the voltage-dividing coupling unit 3 and the dielectric-loss measuring unit 5 both work normally, at this time, the device works in a voltage-withstand, partial-discharge and dielectric-loss mode, after voltage boosting, not only is the voltage-withstand test performed on the tested cable, but also the partial-discharge and dielectric-loss values are measured while voltage is being withstand, and voltage-withstand, partial-discharge and dielectric-loss conclusions can be given after the test.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one position, or may be distributed on multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit may be implemented in the form of hardware, or may also be implemented in the form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be substantially implemented or contributed to by the prior art, or all or part of the technical solution may be embodied in a software product, which is stored in a storage medium and includes instructions for executing all or part of the steps of the method described in the embodiments of the present application through a computer device (which may be a personal computer, a server, or a network device). And the aforementioned storage medium includes: a U disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.
Claims (8)
1. A power supply circuit for cable integrity testing, comprising: the device comprises a negative polarity high-voltage power supply circuit, a positive polarity high-voltage power supply circuit, a voltage division coupling unit, a cable to be tested and a dielectric loss measurement unit;
the negative polarity high-voltage power supply circuit comprises a first adjustable high-frequency alternating-current power supply, a first high-frequency high-voltage transformer, a first resistor group, a first capacitor group, a first light-operated semiconductor switch group and a first high-voltage silicon stack group;
the positive polarity high-voltage power supply circuit comprises a second adjustable high-frequency alternating-current power supply, a second high-frequency high-voltage transformer, a second resistor group, a second capacitor group, a second light-operated semiconductor switch group and a second high-voltage silicon stack group;
the negative polarity high-voltage power supply circuit and the positive polarity high-voltage power supply circuit have the same circuit connection structure and are connected in parallel;
the first light-operated semiconductor switch group comprises a first light-operated semiconductor switch and a second light-operated semiconductor switch;
the second light-operated semiconductor switch group comprises a third light-operated semiconductor switch and a fourth light-operated semiconductor switch;
the first high-voltage silicon stack group comprises a first high-voltage silicon stack and a second high-voltage silicon stack;
the second high-voltage silicon stack group comprises a third high-voltage silicon stack and a fourth high-voltage silicon stack;
the voltage division coupling unit comprises a third resistor group and a third capacitor group;
the dielectric loss measuring unit comprises a voltage dividing resistor group, a current transformer, a collecting card and an industrial personal computer;
and the current transformer is electrically connected with one end of the cable to be tested.
2. The power supply circuit for cable complex test according to claim 1, further comprising: a high voltage inductor;
the high-voltage inductor is connected between the negative polarity high-voltage power supply circuit and the voltage division coupling unit.
3. The power supply circuit for cable integrity testing of claim 1, wherein said first resistor group comprises a first resistor and a second resistor;
the second resistor group comprises a third resistor and a fourth resistor;
the third resistor group comprises a fifth resistor and a sixth resistor;
the voltage division resistor group comprises a seventh resistor and an eighth resistor.
4. The power supply circuit for cable complex testing according to claim 3, wherein said first capacitor bank comprises a first capacitor and a second capacitor;
the second capacitor bank comprises a third capacitor and a fourth capacitor;
the third capacitor bank includes a fifth capacitor and a sixth capacitor.
5. The power supply circuit for cable complex test according to claim 4, wherein one end of the fifth resistor is connected to one end of the sixth resistor;
one end of the fifth capacitor is connected with one end of the sixth capacitor;
the other end of the fifth resistor and the other end of the fifth capacitor are both connected with the voltage dividing resistor group;
the other end of the sixth resistor and the other end of the sixth capacitor are both connected with the PD coupling unit.
6. The power supply circuit for cable complex test according to claim 4, wherein the seventh resistor and the eighth resistor in the voltage dividing resistor set are connected in series, and one end of the eighth resistor is grounded.
7. The power supply circuit for cable comprehensive test according to claim 6, wherein the current transformer and the voltage dividing resistor group are both connected with the input end of the acquisition card;
and the output end of the acquisition card is connected with the input end of the industrial personal computer.
8. The power supply circuit for cable complex test according to claim 1, wherein the dielectric loss measuring unit further comprises: a communication module;
the communication module is connected with the industrial personal computer and used for communicating the industrial personal computer with an upper computer.
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| CN106990341B (en) * | 2017-05-26 | 2023-05-02 | 西安交通大学 | Ultralow-frequency cosine square wave high-voltage generator and method for insulation diagnosis of distribution cable |
| CN107449970A (en) * | 2017-09-28 | 2017-12-08 | 国网安徽省电力公司检修公司 | Insulaion resistance and the test integrated device of dielectric loss |
| CN111624452B (en) * | 2020-05-14 | 2022-07-26 | 广东电网有限责任公司 | High-voltage generator for insulation test of distribution cable |
| CN111693802A (en) * | 2020-05-22 | 2020-09-22 | 国网河北省电力有限公司电力科学研究院 | Frequency-adjustable cosine square wave voltage generation device and method |
| CN111880064A (en) * | 2020-08-03 | 2020-11-03 | 国网山东省电力公司威海供电公司 | Cable voltage-withstanding partial discharge synchronous detection device |
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