CN216621506U - Cubical switchboard generating line temperature rise monitoring circuit - Google Patents
Cubical switchboard generating line temperature rise monitoring circuit Download PDFInfo
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- CN216621506U CN216621506U CN202220043855.2U CN202220043855U CN216621506U CN 216621506 U CN216621506 U CN 216621506U CN 202220043855 U CN202220043855 U CN 202220043855U CN 216621506 U CN216621506 U CN 216621506U
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- switch cabinet
- resistance
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- 238000012544 monitoring process Methods 0.000 title claims abstract description 30
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 38
- 229910052802 copper Inorganic materials 0.000 claims abstract description 37
- 239000010949 copper Substances 0.000 claims abstract description 37
- 239000003990 capacitor Substances 0.000 claims abstract description 17
- 230000000903 blocking effect Effects 0.000 claims abstract description 4
- 238000005259 measurement Methods 0.000 claims description 31
- 238000006243 chemical reaction Methods 0.000 claims description 19
- 238000005070 sampling Methods 0.000 claims description 11
- 239000004020 conductor Substances 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 238000009434 installation Methods 0.000 description 4
- 238000009529 body temperature measurement Methods 0.000 description 3
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 3
- 238000009413 insulation Methods 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 206010000369 Accident Diseases 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011900 installation process Methods 0.000 description 1
- 230000016507 interphase Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
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Abstract
The utility model discloses a switch cabinet bus temperature rise monitoring circuit which comprises a resistance measuring circuit, wherein according to the relation between resistance change and temperature change between two ends of a copper bus, the resistance change between the two ends of the copper bus of a switch cabinet is measured by the resistance measuring circuit to monitor the temperature rise state between the two ends of the copper bus of the switch cabinet, two resistance measuring ends of the resistance measuring circuit output direct current voltages, the two resistance measuring ends measured by the resistance measuring circuit are respectively connected with coil reactors, the other ends of the two coil reactors are connected with capacitors in parallel, the other ends of the two coil reactors are simultaneously connected with the two ends of the copper bus of the switch cabinet to be measured, the capacitors are used for short-circuiting alternating current voltages generated by alternating current flowing through the copper bus at the two ends of the copper bus, and the coil reactors are used for blocking the circulation of the alternating current generated by the alternating current voltage at the two resistance measuring ends of the resistance measuring circuit. The circuit is simple and reliable, and more choices are provided for monitoring the temperature rise of the switch cabinet bus.
Description
Technical Field
The utility model relates to a switch cabinet bus temperature rise monitoring circuit.
Background
The high-low voltage switch cabinet of the power distribution station is important electrical equipment in a power supply and distribution system, and in the long-term operation process of the equipment, due to ventilation faults of a power distribution room, when large current flows in a bus in the switch cabinet, the temperature of the bus is higher than a standard value, or the temperature of the bus is higher than the standard value, or the temperature of a main bus in the switch cabinet is higher than the standard value, or the temperature of the main bus in the switch cabinet is lower than the standard value, and the temperature of the main bus in the switch cabinet, the high-low voltage switch cabinet, and the high voltage switch cabinet are aged or the parts such as the contact of the switch contacts, so as the aging or the equipment, the high voltage of the high voltage, and the high voltage, the high voltage switch cabinet, the high voltage, the high. And the long-time overload operation of the bus, the overload protection has no reliable action, and the bus can be seriously heated under the action of the current heat effect. The performance of the adjacent insulating parts of the bus is degraded due to the overhigh temperature of the bus, so that inter-phase short circuit fault tripping and grounding short circuit fault tripping occur, and the reliability of power supply is influenced. In severe cases, even fire accidents occur, and the equipment of crisis personnel is safe, so that large-area accident power failure is caused. For this purpose, thermocouple temperature sensors, SW color chips, optical fiber technology can be used for contact measurement or infrared temperature measurement can be used for non-contact monitoring to avoid accidents. However, performing contact measurement requires multipoint installation, multipoint measurement, and installation is cumbersome, and each installation point needs to ensure stable insulation performance. Especially, when the high-voltage switch cabinet is installed, the insulating property of each installation point needs to be ensured, the installation process requirement is high, and the cost is high. When the non-contact measurement is carried out, the bus is in a high-current strong magnetic field environment, the wireless temperature measurement is easily interfered by the magnetic field, and the cost of the wireless temperature measurement complete equipment is high; in addition, to some narrow and small high tension switchgear in space, temperature acquisition equipment can't rationally install, for this reason, can find the mode of more suitable bus temperature control and provide the selection to cubical switchboard bus temperature rise monitoring.
Disclosure of Invention
The utility model aims to provide a switch cabinet bus temperature rise monitoring circuit, which realizes the monitoring of the bus temperature rise of a switch cabinet by adopting a mode of measuring the bus resistance change according to the physical phenomenon that the conductivity of a copper material is changed and increased along with the temperature rise, can realize the monitoring of the bus temperature rise of the switch cabinet by only connecting two measuring points of the circuit into two ends of the bus of the switch cabinet, is simple and reliable, and provides more choices for the monitoring of the bus temperature rise of the switch cabinet.
In order to achieve the purpose, the scheme of the utility model is as follows:
the utility model provides a cubical switchboard generating line temperature rise monitoring circuit, including resistance measurement circuit, resistance measurement circuit is according to the relation of resistance change and temperature variation between the copper generating line both ends, through surveying the resistance change monitoring cubical switchboard temperature rise state between the copper generating line both ends between the cubical switchboard copper generating line both ends, two resistance measurement ends output direct current voltage of resistance measurement circuit, wherein, two resistance measurement ends that resistance measurement circuit measured are connected with the coil reactor respectively, two coil reactor other ends connect simultaneously has electric capacity, the other end of two coil reactors connects the both ends of being surveyed cubical switchboard copper generating line simultaneously, electric capacity is used for short circuit copper generating line both ends by the alternating current that the copper generating line resistance produced, the circulation of alternating current that the coil reactor was used for blocking alternating current at two resistance measurement ends of resistance measurement circuit.
The scheme is further as follows: the resistance measuring circuit comprises a Wheatstone bridge resistance measuring circuit which is provided with two resistance measuring ends, the balance voltage output of the Wheatstone bridge resistance measuring circuit is connected with a voltage comparator, and the output of the voltage comparator is connected with an alarm through a driving circuit.
The scheme is further as follows: the balance voltage output of the Wheatstone bridge resistance measuring circuit is simultaneously connected with the analog input of the A/D conversion circuit, the digital output of the A/D conversion circuit is connected with the microprocessor circuit, the output of the microprocessor circuit is connected with the display, and the microprocessor circuit calculates and converts the input analog voltage value into a temperature value and outputs the temperature value to the display.
The scheme is further as follows: the resistance measuring circuit comprises a direct current constant current source, the two output ends of the direct current constant current source are the two resistance measuring ends, the two resistance measuring ends are simultaneously connected with a voltage comparator, and the output of the voltage comparator is connected with an alarm through a driving circuit.
The scheme is further as follows: the output of the direct current constant current source is simultaneously connected with the analog input of the A/D conversion circuit, the digital output of the A/D conversion circuit is connected with the microprocessor circuit, the output of the microprocessor circuit is connected with the display, and the microprocessor circuit calculates and converts the input analog voltage value into a temperature value and outputs the temperature value to the display.
The scheme is further as follows: the resistance measuring circuit comprises a direct current constant voltage source, the direct current constant voltage source outputs and forms the two resistance measuring ends after passing through a sampling resistor, two ends of the sampling resistor are connected with a voltage comparator, and the output of the voltage comparator is connected with an alarm through a driving circuit.
The scheme is further as follows: the two ends of the sampling resistor are simultaneously connected with analog input of the A/D conversion circuit, digital output of the A/D conversion circuit is connected with the microprocessor circuit, output of the microprocessor circuit is connected with the display, and the microprocessor circuit converts an input analog voltage value into a temperature value through calculation and outputs the temperature value to the display.
The utility model has the beneficial effects that: the circuit realizes the monitoring of the temperature rise of the bus of the switch cabinet by adopting a mode of measuring the resistance change of the copper bus according to the physical phenomenon that the conductivity of copper materials is increased along with the temperature rise, the monitoring of the temperature rise of the bus of the switch cabinet can be realized only by connecting two resistance measuring ends of the bus temperature rise monitoring circuit into two ends of the bus of the switch cabinet, and because an inductor and a short-circuit capacitor are connected into a voltage output end of the circuit, the input of alternating voltage and current is avoided, the circuit is simple and reliable, and more choices are provided for the monitoring of the temperature rise of the bus of the switch cabinet.
The utility model is described in detail below with reference to the figures and examples.
Drawings
FIG. 1 is a schematic diagram of the circuit structure of the present invention;
FIG. 2 is a schematic diagram of a Wheatstone bridge resistance measurement circuit for measurement according to the present invention;
FIG. 3 is a schematic diagram of the present invention using a DC constant current source for measurement;
FIG. 4 is a schematic diagram of the measurement performed by the DC constant voltage source according to the present invention.
In the figure: 1-a resistance measurement circuit; 101-resistance measuring terminal; 102-a wheatstone bridge resistance measurement circuit; 103-a direct current constant current source; 104-a direct current constant voltage source; 2-bus bar; 3-a voltage comparator; 4-a drive circuit; 5-an alarm; a 6-A/D conversion circuit; 7-a microprocessor circuit; 8-display.
Detailed Description
A temperature rise monitoring circuit for a switch cabinet bus is shown in figure 1 and comprises a resistance measuring circuit 1, wherein the resistance measuring circuit monitors the temperature rise state between two ends of the switch cabinet copper bus by measuring the resistance change between the two ends of the switch cabinet copper bus according to the relation between the resistance change and the temperature change between the two ends of the copper bus, the resistance measuring circuit is an active circuit, therefore, two resistance measuring ends 101 of the resistance measuring circuit output direct current voltages, wherein the two resistance measuring ends measured by the resistance measuring circuit are respectively connected with a coil reactor L, the other end of the two coil reactors L is connected with a capacitor C in parallel, the other end of the two coil reactors L is simultaneously connected with two ends of a tested switch cabinet copper bus 2, the capacitor C is used for short-circuiting alternating current voltages generated by alternating current flowing through the copper bus resistor at the two ends of the copper bus 2, and the coil reactor L is used for blocking alternating current voltages generated by the alternating current voltages at the two resistance measuring ends of the resistance measuring circuit And (4) current circulation.
As is well known, the magnitude of the dc resistance of any conductor is generally related to temperature, material, length, and cross-sectional area. For a conductor with a uniform cross section, the magnitude of the dc resistance value can be formulated as: r =
l/S, in the formula
Is the resistivity of the material (ohm/meter); l is the length of the conductor (meters); s is the cross-sectional area of the conductor (mm). While resistivity varies with the material and temperature of the conductor. The resistivity of the metal changes linearly with temperature, and the conductor has different direct current resistance values at different temperatures.
As shown in figure 1, a measurement point is taken as a point A on a bus line inlet side 2 of a certain phase of a switch cabinet, and a measurement point is taken as a point B on the tail end of the same phase of the bus line of the switch cabinet. A. B two points are respectively connectedA section of lead wire is produced, the lead wire can be a copper core insulated wire, for a high-voltage switch cabinet with the nominal voltage exceeding 1kV, the lead wire should be a test wire shielded by a high-voltage belt, and the resistance measuring circuit should meet the ground insulation requirement. The ends of the lead are respectively a and b, after the bus is electrified, the potential of the points a and b relative to the ground potential is a phase voltage effective value, and the potential of the points a and b relative to the other two phases of buses is a line voltage effective value. a. The end B is connected with a resistance measuring circuit which can send out direct current, when the direct current flows through a measured element, voltage drop is generated, according to ohm law, the direct current resistance of the element is equal to the voltage at two ends of the element divided by the current flowing through the element, when the bus works with a high-power load, the electric potentials of the point A and the point B are not equal any more, and UAB = UA-UB, namely the voltage loss value between the bus A and the bus B. At this time, Uab>0V, if the terminals a, b are directly connected to the resistance measuring circuit, a large measurement error occurs and the resistance measuring circuit is damaged. Therefore, a high inductance value reactor L is required to be connected in series between the two output ends of the resistance measurement circuit and the ends a and b, and a low capacitance reactance capacitor C is required to be connected between the ends a and b. The reactor has the function of isolating alternating current and direct current, and the capacitor C has the function of isolating alternating current and direct current. a. b low capacitive reactance capacitor C between the ends, the direct current output by the resistance measuring circuit can not flow through the capacitor, but the alternating current can directly flow and be short-circuited, at the moment, the Uab value is equal to the effective value of the alternating current flowing through the lead multiplied by the capacitive reactance value of the capacitor, the alternating current flowing through the lead can be regarded as the minimum part of the shared bus load current, the capacitive reactance value of the capacitor C is inversely proportional to the capacity of the capacitor C, and when the capacitor with the capacity of 2 farads is selected, Xc =1 ^ is selected
c = 1/(314 × 2) =0.0016 ohm, and if the effective value of the alternating current flowing through the lead is 30A, Uab =30 × 0.0016=0.048V, that is, Uab ≈ 0V. a. b high-inductance reactor L with two ends connected with resistance measuring circuit in series, the DC current output by the resistance measuring circuit can flow directly, and 5H inductor, X, is selectedL=
L =314 × 5=1570 ohms, and the high inductance can block the flow of alternating current from the lead into the resistance measurement circuit. Therefore, the measurement error of the resistance measurement circuit can be greatly reduced by the matching use of the capacitor and the reactor, and the resistance measurement circuit can not be damaged.
The resistance measuring circuit in the embodiment has several preferable schemes:
firstly, as shown in fig. 2, the resistance measuring circuit includes a known wheatstone bridge resistance measuring circuit 102, the wheatstone bridge resistance measuring circuit 102 includes resistors R2 and R3, an adjustable resistor R1 and a stable power source E, wherein the resistor Rx to be measured is a resistor between two ends of the copper bus, therefore, the two resistance measuring ends of the wheatstone bridge resistance measuring circuit are the two resistance measuring ends 101, two ends of the measuring voltage V in the wheatstone bridge resistance measuring circuit are balanced voltage outputs, calibration is performed before operation, that is, the adjustable resistor R1 is adjusted to make the voltage V display 0 under the normal room temperature and the state that the copper bus does not operate, the resistance increases with the temperature after the copper bus is electrified, so the voltage V display is not 0, the temperature increase of the copper bus can be displayed by the change of the voltage V, and monitoring is enabled, the balance voltage output in the Wheatstone bridge resistance measuring circuit is connected with a voltage comparator 3, the output of the voltage comparator 3 is connected with an alarm 5 through a driving circuit 4, and thus when the temperature rises to a certain degree, the output of the voltage comparator 3 drives the alarm 5 to alarm through the driving circuit 4.
To enable an intuitive temperature rise: the balance voltage output of the Wheatstone bridge resistance measuring circuit is simultaneously connected with the analog input of the A/D conversion circuit 6, the digital output of the A/D conversion circuit 6 is connected with the microprocessor circuit 7, the output of the microprocessor circuit is connected with the display 8, and the microprocessor circuit converts the input analog voltage value into a temperature value through calculation and outputs the temperature value to the display.
Second, as shown in fig. 3: the resistance measuring circuit comprises a direct current constant current source 103, two output ends of the direct current constant current source are the two resistance measuring ends 101, the two resistance measuring ends are simultaneously connected with a voltage comparator 3, and the output of the voltage comparator 3 is connected with an alarm 5 through a driving circuit 4.
To enable an intuitive temperature rise: the output of the direct current constant current source is simultaneously connected with the analog input of the A/D conversion circuit 6, the digital output of the A/D conversion circuit 6 is connected with the microprocessor circuit 7, the output of the microprocessor circuit is connected with the display 8, and the microprocessor circuit calculates and converts the input analog voltage value into a temperature value and outputs the temperature value to the display. Because the constant current source is adopted, when the temperature rising resistance of the copper bus is increased, in order to ensure that the voltage output by the direct current constant current source is increased as the current is not changed, the temperature change of the copper bus can be monitored by monitoring the voltage output by the direct current constant current source.
Third, as shown in fig. 4: the resistance measuring circuit comprises a direct current constant voltage source 104, the direct current constant voltage source 104 is output through a sampling resistor R4 to form two resistance measuring ends 101, two ends of the sampling resistor are connected with a voltage comparator 3, and the output of the voltage comparator 3 is connected with an alarm 5 through a driving circuit 4.
As in the first two, in order to be able to visualize the temperature increase: the two ends of the sampling resistor R4 are simultaneously connected with the analog input of the A/D conversion circuit 6, the digital output of the A/D conversion circuit 6 is connected with the microprocessor circuit 7, the output of the microprocessor circuit 7 is connected with the display 8, and the microprocessor circuit calculates and converts the input analog voltage value into a temperature value and outputs the temperature value to the display. Because the constant voltage source is adopted, when the temperature rising resistance of the copper bus is increased, the direct current is reduced when the voltage is not changed, the voltage at two ends of the sampling resistor R4 is reduced, and the temperature change of the copper bus can be monitored by monitoring the voltage change at two ends of the sampling resistor R4.
According to the physical phenomenon that the conductivity of copper materials is increased along with the temperature, the temperature rise of the switch cabinet bus is realized by measuring the resistance change of the copper bus, the temperature rise of the switch cabinet bus can be monitored by only connecting two resistance measuring ends of the bus temperature rise monitoring circuit into two ends of the switch cabinet bus, and because an inductor and a short-circuit capacitor are connected into a voltage output end of the circuit, the input of alternating voltage and current is avoided, the circuit is simple and reliable, and more choices are provided for monitoring the temperature rise of the switch cabinet bus.
Claims (7)
1. A temperature rise monitoring circuit for a switch cabinet bus comprises a resistance measuring circuit, wherein the resistance measuring circuit is used for measuring the temperature rise of the bus according to the relationship between the resistance change and the temperature change between two ends of a copper bus, the temperature rise state between the two ends of the copper bus of the switch cabinet is monitored by measuring the resistance change between the two ends of the copper bus of the switch cabinet, the two resistance measuring ends of the resistance measuring circuit output direct current voltage, the short-circuit switch cabinet is characterized in that two resistance measuring ends measured by the resistance measuring circuit are respectively connected with a coil reactor, the other ends of the two coil reactors are connected with a capacitor in parallel, the other ends of the two coil reactors are simultaneously connected with two ends of a copper bus of a tested switch cabinet, the capacitor is used for short-circuiting alternating-current voltage generated by alternating-current flowing through the copper bus resistance at the two ends of the copper bus, and the coil reactors are used for blocking the circulation of the alternating-current generated by the alternating-current voltage at the two resistance measuring ends of the resistance measuring circuit.
2. The switch cabinet bus temperature rise monitoring circuit according to claim 1, wherein the resistance measuring circuit comprises a Wheatstone bridge resistance measuring circuit having the two resistance measuring terminals, a balanced voltage output of the Wheatstone bridge resistance measuring circuit is connected to a voltage comparator, and an output of the voltage comparator is connected to the alarm through the driving circuit.
3. The switch cabinet bus temperature rise monitoring circuit according to claim 2, wherein a balanced voltage output of the Wheatstone bridge resistance measuring circuit is simultaneously connected with an analog input of the A/D conversion circuit, a digital output of the A/D conversion circuit is connected with a microprocessor circuit, an output of the microprocessor circuit is connected with a display, and the microprocessor circuit calculates and converts an input analog voltage value into a temperature value and outputs the temperature value to the display.
4. The switch cabinet bus temperature rise monitoring circuit according to claim 1, wherein the resistance measurement circuit comprises a direct current constant current source, two output ends of the direct current constant current source are the two resistance measurement ends, the two resistance measurement ends are simultaneously connected with a voltage comparator, and the output of the voltage comparator is connected with an alarm through a driving circuit.
5. The switch cabinet bus temperature rise monitoring circuit according to claim 4, wherein the output of the DC constant current source is simultaneously connected with the analog input of the A/D conversion circuit, the digital output of the A/D conversion circuit is connected with the microprocessor circuit, the output of the microprocessor circuit is connected with the display, and the microprocessor circuit converts the input analog voltage value into the temperature value through calculation and outputs the temperature value to the display.
6. The switch cabinet bus temperature rise monitoring circuit according to claim 1, wherein the resistance measurement circuit comprises a direct current constant voltage source, the direct current constant voltage source outputs through a sampling resistor to form the two resistance measurement ends, two ends of the sampling resistor are connected with a voltage comparator, and the output of the voltage comparator is connected with an alarm through a driving circuit.
7. The switch cabinet bus temperature rise monitoring circuit according to claim 6, wherein two ends of the sampling resistor are simultaneously connected with analog inputs of an A/D conversion circuit, digital outputs of the A/D conversion circuit are connected with a microprocessor circuit, an output of the microprocessor circuit is connected with a display, and the microprocessor circuit converts an input analog voltage value into a temperature value through calculation and outputs the temperature value to the display.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220043855.2U CN216621506U (en) | 2022-01-10 | 2022-01-10 | Cubical switchboard generating line temperature rise monitoring circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220043855.2U CN216621506U (en) | 2022-01-10 | 2022-01-10 | Cubical switchboard generating line temperature rise monitoring circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216621506U true CN216621506U (en) | 2022-05-27 |
Family
ID=81687500
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202220043855.2U Expired - Fee Related CN216621506U (en) | 2022-01-10 | 2022-01-10 | Cubical switchboard generating line temperature rise monitoring circuit |
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| Country | Link |
|---|---|
| CN (1) | CN216621506U (en) |
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2022
- 2022-01-10 CN CN202220043855.2U patent/CN216621506U/en not_active Expired - Fee Related
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Granted publication date: 20220527 |