CN106405242B - On-line monitoring device and detection method for direct-current resistance of isolating switch - Google Patents
On-line monitoring device and detection method for direct-current resistance of isolating switch Download PDFInfo
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- CN106405242B CN106405242B CN201610865373.4A CN201610865373A CN106405242B CN 106405242 B CN106405242 B CN 106405242B CN 201610865373 A CN201610865373 A CN 201610865373A CN 106405242 B CN106405242 B CN 106405242B
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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
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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
- G01R31/327—Testing of circuit interrupters, switches or circuit-breakers
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- Measurement Of Current Or Voltage (AREA)
- Measurement Of Resistance Or Impedance (AREA)
Abstract
The invention discloses an on-line monitoring device and a detection method for a direct-current resistor of an isolating switch, wherein the on-line monitoring device comprises a first branch and a second branch which are connected in parallel, and the first branch is sequentially connected with a current-limiting resistor, a first coupling capacitor, a high-frequency power supply, a second coupling capacitor, a precision resistor and a first coupling inductor in series, wherein the precision resistor is connected with a first voltage measurement module for measuring voltages at two ends of the precision resistor; a third coupling capacitor, a fourth coupling capacitor and a second coupling inductor are sequentially connected in series on the second branch, and meanwhile, a wiring is led out between the third coupling capacitor and the fourth coupling capacitor and is connected with a second voltage measurement module; the first voltage measurement module and the second voltage measurement module are connected with the controller, and the controller is connected with the display module, the power-on display module, the communication module and the storage module. The invention can know the state of the isolating switch in time, eliminates the heating problem of the isolating switch in sprouting, and reduces the infrared temperature measurement of the transformer substation for special inspection staff.
Description
Technical Field
The invention relates to the technical field of online monitoring of power systems, in particular to an online monitoring device and a detection method for a direct-current resistor of an isolating switch.
Background
A disconnector, an electrical device, in which the contacts have a switching device which, in the separated position, has a contact opening which corresponds to a defined insulation distance and which is distinct, and in the closed position, is capable of carrying both a current under normal circuit conditions and a current under abnormal conditions (for example, short circuits) for a defined period of time.
The isolating switch has contact resistance between the contact and the contact (or contact finger) in the working process, the contact resistance of the contact can be increased by the isolating switch which is separated and combined for many times in the running process, the contact resistance is increased to heat the contact, and the contact can be burnt out under severe conditions to cause power failure accidents. At present, three methods exist for preventing the heat generation of the disconnecting switch contact: the color of the contact is observed manually, the loop resistance is measured periodically, and the infrared temperature measurement method is adopted. All three methods need workers to go to the transformer substation site to patrol, and have large workload, low working efficiency and incapability of finding problems in time.
Disclosure of Invention
The invention aims to solve the problems, and provides an on-line monitoring device and a detection method for a direct-current resistor of a disconnecting switch, which can know the state of the disconnecting switch in time and eliminate the heating problem of the disconnecting switch in sprouting.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the on-line monitoring device for the direct-current resistor of the isolating switch comprises a first branch and a second branch which are connected in parallel, wherein a current-limiting resistor, a first coupling capacitor, a high-frequency power supply, a second coupling capacitor, a precision resistor and a first coupling inductor are sequentially connected in series on the first branch, and the precision resistor is connected with a first voltage measuring module for measuring voltages at two ends of the precision resistor;
a third coupling capacitor, a fourth coupling capacitor and a second coupling inductor are sequentially connected in series on the second branch, and meanwhile, a wiring is led out between the third coupling capacitor and the fourth coupling capacitor and is connected with a second voltage measurement module;
the first voltage measurement module and the second voltage measurement module are connected with the controller, and the controller is connected with the display module, the power-on display module, the communication module and the storage module.
The first voltage measurement module comprises an operational amplifier U3, wherein the positive input end of the operational amplifier U3 is connected with analog ground, the negative input end of the operational amplifier U3 is connected with a precision resistor, a capacitor R1 and a capacitor C1 are connected in parallel between the negative input end and the output end, the output end is connected with the capacitor C4 and then connected with analog ground, and meanwhile, the output end is connected with the positive input end of the operational amplifier U2 in series with the capacitor C2 and the capacitor C3;
a resistor R2 is connected in series between the common end of the capacitor C2 and the capacitor C3 and the output end of the operational amplifier U2, a resistor R5 is connected in series between the common end of the capacitor C2 and the capacitor C3 and the analog ground, a resistor R6 is connected between the negative input end of the operational amplifier U2 and the analog ground, and a resistor R7 is connected in series between the negative input end of the operational amplifier U2 and the output end of the operational amplifier U2;
the output end of the operational amplifier U2 is connected with the positive input end of the operational amplifier U1 in series with the resistor R4, and the negative input end of the operational amplifier U1 is connected with the output end of the operational amplifier U1 and then connected to the input end of the controller.
The second voltage measurement module comprises an operational amplifier U6, wherein the positive input end of the operational amplifier U6 is connected with analog ground, the negative input end of the operational amplifier U6 is connected between the third coupling capacitor and the fourth coupling capacitor, a capacitor R8 and a capacitor C5 are connected in parallel between the negative input end and the output end, the output end is connected with the capacitor C8 and then connected with analog ground, and meanwhile, the output end is connected with the positive input end of the operational amplifier U5 in series with the capacitor C6 and the capacitor C7;
a resistor R9 is connected in series between the common end of the capacitor C6 and the capacitor C7 and the output end of the operational amplifier U5, a resistor R12 is connected in series between the common end of the capacitor C6 and the capacitor C7 and the analog ground, a resistor R13 is connected between the negative input end of the operational amplifier U5 and the analog ground, and a resistor R14 is connected in series between the negative input end of the operational amplifier U5 and the output end of the operational amplifier U5;
the output end of the operational amplifier U5 is connected with the positive input end of the operational amplifier U4 in series with the resistor R11, and the negative input end of the operational amplifier U4 is connected with the output end of the operational amplifier U4 and then connected with the input end of the controller.
The storage module comprises an electrically erasable programmable read-only memory chip, a clock end of the electrically erasable programmable read-only memory chip is connected with a crystal oscillator, a serial clock pin and a serial data pin are respectively connected with resistors R19 and R20 and then connected with a 3.3V power supply, and meanwhile, the serial clock pin and the serial data pin are connected with the controller; meanwhile, the backup power input pin of the EEPROM chip is connected with the diode D1 and then connected with a 3.3V power supply.
The power-on display module comprises a light emitting diode D5, wherein the negative electrode of the light emitting diode D5 is grounded, the positive electrode of the light emitting diode D5 is connected with one end of a resistor R17 and the input end of an inverter U9A, the other end of the resistor R17 is connected with a power supply, a resistor R15 and a light emitting diode D3 are connected between the output end of the inverter U9A and the power supply, and the power supply is also connected with a resistor R16 and a light emitting diode D4 and then connected with the output end of an inverter U9B; the input end of the inverter U9A and the input end of the inverter U9B are connected with pins of the controller.
The display module adopts a liquid crystal display.
The detection method adopting the on-line monitoring device for the direct-current resistance of the isolating switch comprises the following steps: the first branch and the second branch are connected in parallel and then connected in series with the isolating switch to be tested, the voltage V1 at two ends of the precise resistor is measured through the first voltage measuring module, and the voltage V2 at two sides of the isolating switch is measured through the second voltage measuring module;
the first voltage measurement module and the second voltage measurement module send the measured results to a controller, and the controller sends the measured results to the controller according to the formula: calculating V1/V2 = R1'/R2' to obtain a direct current resistor R2 'of the isolating switch, wherein R1' is a resistor of the precision resistor;
the controller displays the calculated direct current resistance of the isolating switch through the display module and sends the acquired resistance value to an external terminal needing data through the communication module.
The invention has the beneficial effects that:
the device provided by the invention can detect the direct current resistance of the isolating switch in real time, can know the state of the isolating switch in time, eliminates the heating problem of the isolating switch in sprouting, and reduces the infrared temperature measurement of the transformer substation by special inspection staff.
Drawings
FIG. 1 is a schematic diagram of the present invention;
FIG. 2 is a circuit diagram of a controller according to the present invention;
FIG. 3 is a circuit diagram of a first voltage measurement module;
FIG. 4 is a circuit diagram of a second voltage measurement module;
FIG. 5 is a circuit diagram of a power-on display module;
FIG. 6 is a circuit diagram of a memory module;
fig. 7 is a circuit diagram of a display module.
Wherein, 1-isolator.
Detailed Description
The invention will be further described with reference to the drawings and examples.
As shown in fig. 1, an on-line monitoring device for a direct current resistor of an isolating switch comprises a first branch and a second branch which are connected in parallel, wherein a current-limiting resistor RR1, a first coupling capacitor CC1, a high-frequency power supply, a second coupling capacitor CC3, a precision resistor RR2 and a first coupling inductor LL1 are sequentially connected in series on the first branch, and the precision resistor RR2 is connected with a first voltage measurement module V1 for measuring voltages at two ends of the precision resistor;
the second branch is sequentially connected with a third coupling capacitor CC2, a fourth coupling capacitor CC4 and a second coupling inductor LL2 in series, and meanwhile, a lead-out wiring between the third coupling capacitor CC2 and the fourth coupling capacitor CC4 is connected with a second voltage measurement module V2;
the first voltage measurement module and the second voltage measurement module are connected with the controller, and the controller is connected with the display module, the power-on display module, the communication module and the storage module.
The first coupling capacitor CC1 plays an isolating role, the second coupling capacitor CC3 and the first coupling inductor LL1 jointly form a coupling filter, and the coupling filter can block the power frequency current of 50Hz through the high-frequency current of 1MkHz to prevent the high voltage of the power frequency from entering a measuring loop. The two sides are respectively provided with a set of filtering structure for preventing the whole loop from being conducted when one coupling capacitor is broken down when the isolating switch is positioned at the opening position, so that the isolating switch is short-circuited, and the isolating switch loses the closing function; and the voltage at two ends of the isolating switch can be divided when the isolating switch is disconnected, so that the circuit board is prevented from being burnt out after the voltage enters the control loop. The third coupling capacitance CC2, the fourth coupling capacitance CC4 and the second coupling inductance LL2 are the same principle as mentioned above for CC1, CC3, LL 1.
The function of the precision resistor is to provide a reference resistor, and the resistor of the isolating switch is calculated through the voltage at two ends of the precision resistor and the voltage ratio at two sides of the isolating switch.
The current limiting resistor RR1 has the function of limiting high-frequency current, reducing power consumption and prolonging the service life of equipment.
The resistance value of the current-limiting resistor RR1 is 10Ω, the capacitance value of the first coupling capacitor CC1 is 100pF, and the high-frequency power supply is a 5V power supply of 1 MHz; the capacitance value of the second coupling capacitor CC3 is 100pF; the resistance value of the precision resistor RR2 is 0.1Ω, and the inductance value of the first coupling inductance LL1 is 0.127mH.
The capacitance value of the third coupling capacitor CC2 is 100pF; the capacitance value of the fourth coupling capacitor CC4 is 100pF; the inductance value of the second coupling inductance L2 was 0.127mH.
In this embodiment, the controller is a TMS 320LF2407 controller, and fig. 2 is a circuit diagram of the controller.
As shown in fig. 3, the first voltage measurement module includes an operational amplifier U3, where a positive input end of the operational amplifier U3 is connected to analog ground, a negative input end of the operational amplifier U3 is connected to a precision resistor, a capacitor R1 and a capacitor C1 are connected in parallel between the negative input end and the output end, the output end is connected to the capacitor C4 and then to analog ground, and meanwhile, the output end is connected to the positive input end of the operational amplifier U2 in series with the capacitor C2 and the capacitor C3;
a resistor R2 is connected in series between the common end of the capacitor C2 and the capacitor C3 and the output end of the operational amplifier U2, a resistor R5 is connected in series between the common end of the capacitor C2 and the capacitor C3 and the analog ground, a resistor R6 is connected between the negative input end of the operational amplifier U2 and the analog ground, and a resistor R7 is connected in series between the negative input end of the operational amplifier U2 and the output end of the operational amplifier U2;
the output end of the operational amplifier U2 is connected with the positive input end of the operational amplifier U1 in series with the resistor R4, and the negative input end of the operational amplifier U1 is connected with the output end of the operational amplifier U1 and then connected to the input end of the controller.
As shown in fig. 4, the second voltage measurement module includes an operational amplifier U6, where a positive input end of the operational amplifier U6 is connected to analog ground, a negative input end of the operational amplifier U6 is connected between the third coupling capacitor and the fourth coupling capacitor, a capacitor R8 and a capacitor C5 are connected in parallel between the negative input end and the output end, the output end is connected to the capacitor C8 and then to analog ground, and meanwhile, the output end is connected to the positive input end of the operational amplifier U5 in series with the capacitor C6 and the capacitor C7;
a resistor R9 is connected in series between the common end of the capacitor C6 and the capacitor C7 and the output end of the operational amplifier U5, a resistor R12 is connected in series between the common end of the capacitor C6 and the capacitor C7 and the analog ground, a resistor R13 is connected between the negative input end of the operational amplifier U5 and the analog ground, and a resistor R14 is connected in series between the negative input end of the operational amplifier U5 and the output end of the operational amplifier U5;
the output end of the operational amplifier U5 is connected with the positive input end of the operational amplifier U4 in series with the resistor R11, and the negative input end of the operational amplifier U4 is connected with the output end of the operational amplifier U4 and then connected with the input end of the controller.
As shown in fig. 6, the memory module includes an eeprom chip X1226, clock terminals X1 and X2 of the eeprom chip are connected to a crystal oscillator, a serial clock pin SCL and a serial data pin SDA are respectively connected to resistors R19 and R20 and then connected to a 3.3V power supply, and the serial clock pin SCL and the serial data pin SDA are connected to the controller; meanwhile, a backup power input pin VSACK of the EEPROM chip is connected with a diode D1 and then connected with a 3.3V power supply.
As shown in fig. 5, the power-on display module includes a light emitting diode D5, where a negative electrode of the light emitting diode D5 is grounded, a positive electrode is connected to one end of a resistor R17 and an input end of an inverter U9A, another end of the resistor R17 is connected to a power supply, a resistor R15 and a light emitting diode D3 are connected between an output end of the inverter U9A and the power supply, and the power supply is further connected to a resistor R16 and a light emitting diode D4 and then connected to an output end of the inverter U9B; the input end of the inverter U9A and the input end of the inverter U9B are connected with pins of the controller.
The display module adopts a liquid crystal display, and fig. 7 shows a pin connection diagram of the liquid crystal display.
The detection method adopting the on-line monitoring device for the direct-current resistance of the isolating switch comprises the following steps: the first branch and the second branch are connected in parallel and then connected in series with the isolating switch 1 to be tested (as shown in figure 1), the voltage V1 at two ends of the precise resistor is measured by a first voltage measuring module, and the voltage V2 at two sides of the isolating switch is measured by a second voltage measuring module;
the first voltage measurement module and the second voltage measurement module send the measured results to a controller, and the controller sends the measured results to the controller according to the formula: calculating V1/V2 = R1'/R2' to obtain a direct current resistor R2 'of the isolating switch, wherein R1' is a resistor of the precision resistor;
and the controller displays the calculated direct current resistance of the isolating switch through a display module.
While the foregoing description of the embodiments of the present invention has been presented in conjunction with the drawings, it should be understood that it is not intended to limit the scope of the invention, but rather, it is intended to cover all modifications or variations within the scope of the invention as defined by the claims of the present invention.
Claims (5)
1. The on-line monitoring device for the direct-current resistor of the isolating switch is characterized by comprising a first branch and a second branch which are connected in parallel, wherein a current-limiting resistor, a first coupling capacitor, a high-frequency power supply, a second coupling capacitor, a precision resistor and a first coupling inductor are sequentially connected in series on the first branch, and the precision resistor is connected with a first voltage measuring module for measuring voltages at two ends of the precision resistor;
a third coupling capacitor, a fourth coupling capacitor and a second coupling inductor are sequentially connected in series on the second branch, and meanwhile, a wiring is led out between the third coupling capacitor and the fourth coupling capacitor and is connected with a second voltage measurement module;
the method comprises the steps of connecting a first branch and a second branch in parallel and then connecting the first branch and the second branch with a to-be-detected isolating switch in series, measuring voltage V1 at two ends of a precise resistor through a first voltage measuring module, measuring voltage V2 at two sides of the isolating switch through a second voltage measuring module, and measuring the voltage at two sides of the isolating switch through the second voltage measuring module after connecting the first branch and the second branch in series with the to-be-detected isolating switch;
the first voltage measurement module and the second voltage measurement module are connected with a controller, and the controller is connected with a display module, a power-on display module, a communication module and a storage module;
the power-on display module comprises a light emitting diode D5, wherein the negative electrode of the light emitting diode D5 is grounded, the positive electrode of the light emitting diode D5 is connected with one end of a resistor R17 and the input end of an inverter U9A, the other end of the resistor R17 is connected with a power supply, a resistor R15 and a light emitting diode D3 are connected between the output end of the inverter U9A and the power supply, and the power supply is also connected with a resistor R16 and a light emitting diode D4 and then connected with the output end of an inverter U9B; the input end of the inverter U9A and the input end of the inverter U9B are connected with pins of the controller;
the display module adopts a liquid crystal display.
2. The on-line monitoring device for the direct current resistance of the isolating switch according to claim 1, wherein the first voltage measuring module comprises an operational amplifier U3, the positive input end of the operational amplifier U3 is connected with analog ground, the negative input end of the operational amplifier U3 is connected with a precision resistor, a capacitor R1 and a capacitor C1 are connected in parallel between the negative input end and the output end, the output end is connected with the capacitor C4 and then connected with analog ground, and the output end is connected with the positive input end of the operational amplifier U2 in series with the capacitor C2 and the capacitor C3;
a resistor R2 is connected in series between the common end of the capacitor C2 and the capacitor C3 and the output end of the operational amplifier U2, a resistor R5 is connected in series between the common end of the capacitor C2 and the capacitor C3 and the analog ground, a resistor R6 is connected between the negative input end of the operational amplifier U2 and the analog ground, and a resistor R7 is connected in series between the negative input end of the operational amplifier U2 and the output end of the operational amplifier U2;
the output end of the operational amplifier U2 is connected with the positive input end of the operational amplifier U1 in series with the resistor R4, and the negative input end of the operational amplifier U1 is connected with the output end of the operational amplifier U1 and then connected to the input end of the controller.
3. The on-line monitoring device for the direct current resistance of the isolating switch according to claim 1, wherein the second voltage measuring module comprises an operational amplifier U6, the positive input end of the operational amplifier U6 is connected with analog ground, the negative input end of the operational amplifier U6 is connected between the third coupling capacitor and the fourth coupling capacitor, a capacitor R8 and a capacitor C5 are connected in parallel between the negative input end and the output end, the output end is connected with the capacitor C8 and then connected with analog ground, and the output end is connected with the positive input end of the operational amplifier U5 in series with the capacitor C6 and the capacitor C7;
a resistor R9 is connected in series between the common end of the capacitor C6 and the capacitor C7 and the output end of the operational amplifier U5, a resistor R12 is connected in series between the common end of the capacitor C6 and the capacitor C7 and the analog ground, a resistor R13 is connected between the negative input end of the operational amplifier U5 and the analog ground, and a resistor R14 is connected in series between the negative input end of the operational amplifier U5 and the output end of the operational amplifier U5;
the output end of the operational amplifier U5 is connected with the positive input end of the operational amplifier U4 in series with the resistor R11, and the negative input end of the operational amplifier U4 is connected with the output end of the operational amplifier U4 and then connected with the input end of the controller.
4. The on-line monitoring device for the direct current resistance of the isolating switch according to claim 1, wherein the memory module comprises an electrically erasable programmable read-only memory chip, a clock end of the electrically erasable programmable read-only memory chip is connected with a crystal oscillator, a serial clock pin and a serial data pin are respectively connected with a resistor R19 and a resistor R20 and then connected with a 3.3V power supply, and meanwhile, the serial clock pin and the serial data pin are connected with the controller; meanwhile, the backup power input pin of the EEPROM chip is connected with the diode D1 and then connected with a 3.3V power supply.
5. The detection method adopting the on-line monitoring device for the direct-current resistance of the isolating switch according to claim 1 is characterized by comprising the following steps: the first branch and the second branch are connected in parallel and then connected in series with the isolating switch to be tested, the voltage V1 at two ends of the precise resistor is measured through the first voltage measuring module, and the voltage V2 at two sides of the isolating switch is measured through the second voltage measuring module;
the first voltage measurement module and the second voltage measurement module send the measured results to a controller, and the controller sends the measured results to the controller according to the formula: calculating V1/V2 = R1'/R2' to obtain a direct current resistor R2 'of the isolating switch, wherein R1' is a resistor of the precision resistor;
the controller displays the calculated direct current resistance of the isolating switch through the display module and sends the acquired resistance value to an external terminal needing data through the communication module.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201610865373.4A CN106405242B (en) | 2016-09-29 | 2016-09-29 | On-line monitoring device and detection method for direct-current resistance of isolating switch |
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| CN201610865373.4A CN106405242B (en) | 2016-09-29 | 2016-09-29 | On-line monitoring device and detection method for direct-current resistance of isolating switch |
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| CN106405242B true CN106405242B (en) | 2023-08-15 |
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| CN111308332B (en) * | 2019-11-07 | 2021-01-26 | 广东电网有限责任公司 | Voltage type relay protection tripping circuit contact resistance detection device |
| CN112578185A (en) * | 2020-11-13 | 2021-03-30 | 国网江苏省电力有限公司电力科学研究院 | Device and method for testing direct current resistance of conductor bearing electromagnetic coupling induced potential |
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| CN106405242A (en) | 2017-02-15 |
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