Device and method for measuring temperature characteristic of resistor disc

Abstract

The invention discloses a device and method for measuring the temperature characteristic of a resistor disc, and belongs to the technical field of lightning arrester resistor disc testing. The device comprises a loop inductor, a loop resistor, an ignition sphere gap, a temperature simulation box and a parallel capacitor which are sequentially connected in series, the temperature simulation box can adjust the temperature, and a to-be-tested resistor disc sample is placed and connected in the temperature simulation box; the two ends of the resistor disc test object are connected in parallel with an adjustable resistance box; the two ends of the resistor disc sample are connected in parallel with a voltage divider used for voltage measurement. The lower end of the resistor disc sample is connected in series with a current collector for current measurement. According to the invention, the resistor disc test object is placed in the temperature simulation box so as to obtain different temperatures, the adjustable resistor box is additionally arranged so as to obtain the voltage under the current from dozens of milliamperes to dozens of amperes, and the resistance change trend and the positive and negative temperature coefficient turning point of the test object at different temperatures are further obtained; and an important basis is provided for selection of lightning arrester parameters.

Description

Technical Field

[0001] The invention belongs to the technical field of arrester resistor disc tests, and relates to a device and method for measuring the temperature characteristics of resistor discs. Background Art

[0002] An arrester is an electrical appliance used to protect electrical equipment from high transient overvoltages. The metal oxide resistor disc, an internal functional component thereof, exhibits a negative temperature coefficient characteristic in the small current region. Specifically, as the temperature of the resistor disc increases, its resistance value decreases accordingly, making it easier for current to pass through. However, in the operating environment of the arrester, this characteristic may cause a series of problems. Due to the limited internal space of the arrester and poor heat dissipation conditions, when active power loss generates heat, this heat is difficult to dissipate quickly, resulting in a gradual increase in the temperature of the resistor disc, far higher than the ambient temperature. The increase in the temperature of the resistor disc further exacerbates the resistive current of the arrester. As the temperature rises, the resistive current increases, which not only intensifies the heating of the resistor disc but also threatens the thermal stability of the entire arrester system. If the heat accumulation cannot be effectively controlled, a thermal breakdown phenomenon may occur, and in severe cases, it may even lead to the explosion of the arrester, causing catastrophic consequences to electrical equipment and the entire power system. Especially in multi-column parallel arresters in DC systems, due to factors such as complex structure and uneven current distribution, the risk of thermal breakdown is more significant.

[0003] To deeply study the electrical characteristics of resistor discs and accurately evaluate the performance of arresters, it is necessary to focus on the turning point of the positive and negative temperature coefficients of resistor discs. This turning point marks the critical state where the resistor disc changes from a negative temperature coefficient to a positive temperature coefficient, and is of great significance for studying the performance of resistor discs and designing arrester parameters. However, current research faces technical challenges: the turning point of the positive and negative temperature coefficients of resistor discs usually lies in the current range from milliamperes to amperes, and the measurement accuracy and coverage of existing test equipment in this range are limited, making it impossible to comprehensively and accurately obtain the temperature and resistance change trends in this range. Therefore, accurately measuring the turning point of the positive and negative temperature coefficients of resistor discs is of great significance for the study of resistor disc performance and the design of arrester parameters. Summary of the Invention

[0004] The purpose of the invention is to provide a device and method for measuring the temperature characteristics of resistor discs to solve the technical problem that it is difficult to accurately measure the turning point of the positive and negative temperature coefficients of resistor discs in the prior art.

[0005] To achieve the above purpose, the invention adopts the following technical solutions: In a first aspect, the present invention provides a device for measuring the temperature characteristics of a resistor chip, comprising a loop inductor, a loop resistor, a spark gap, a resistor chip specimen, and a parallel capacitor connected in series in sequence; the resistor chip specimen is disposed in a temperature simulation box capable of adjusting the temperature; adjustable resistor boxes are connected in parallel at both ends of the resistor chip specimen; a voltage divider is further connected in parallel at both ends of the resistor chip specimen for voltage measurement; and a current collector is connected in series with the resistor chip specimen for current measurement.

[0006] Further, the adjustable resistor box includes a plurality of shunt resistor chips connected in parallel, and the resistance is adjusted by the combination and switching of the plurality of shunt resistor chips.

[0007] Further, the performance parameters of the plurality of shunt resistor chips are consistent with those of the resistor chip specimen to be measured.

[0008] Further, the temperature simulation box includes a sealed box body; outlet bushings are installed on both the top surface and the bottom surface of the sealed box body and are respectively connected to the external high-voltage end and low-voltage end; an insulating platform is installed inside the sealed box body; a resistor chip specimen box is installed on the insulating platform, the resistor chip specimen box is connected to the outlet bushing, and the resistor chip specimen is placed in the resistor chip specimen box.

[0009] Further, the resistor chip specimen box includes an insulating cylinder and copper plates located at both ends of the insulating cylinder; an insulating rod is threadedly connected to the bottom end of the insulating cylinder, and the insulating rod passes through the insulating platform and is connected to the bottom of the sealed box body.

[0010] Further, the current collector is a through-core current transformer.

[0011] Further, the measurement accuracy of the through-core current transformer is 0.1.

[0012] Further, the voltage divider is a resistive voltage divider.

[0013] In a second aspect, the present invention provides a method for measuring the temperature characteristics of a resistor chip, based on the above device for measuring the temperature characteristics of a resistor chip, comprising the following steps: Select a plurality of shunt resistor chips and place them in the adjustable resistor box; Place the resistor chip specimen to be measured in the resistor chip specimen box in the temperature simulation box, and connect the resistor chip specimen box to the outlet bushing; Adjust the temperature of the temperature simulation box to heat the resistor chip specimen; Apply voltage to the resistor chip specimen under different waveforms by the combination of charging and discharging of the parallel capacitor, discharging of the spark gap, and the loop inductor and loop resistor; Collect the voltage and current values on the resistor chip specimen in each test through the voltage divider and the current collector.

[0014] Further, the step of selecting a plurality of shunt resistor chips and placing them in the adjustable resistor box specifically includes: Select resistor chips with the same batch performance parameters as the resistor chip samples to be measured, conduct a current sharing test, and select the resistor chips with a current non-uniformity coefficient less than a preset threshold as shunt resistor chips; place the selected shunt resistor chips in the adjustable resistor box.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a device and method for measuring the temperature characteristics of resistor chips. The resistor chip samples are placed in a temperature simulation box, and the temperature simulation box can accurately adjust and maintain the required temperature environment, providing a stable and variable temperature condition for the resistor chip samples, so as to comprehensively and accurately study the electrical characteristics of the resistor chips at different temperatures. A voltage divider is connected in parallel at both ends of the resistor chip samples to accurately measure the voltage across the resistor chips, providing key data for analyzing the voltage-current characteristics of the resistor chips. A current collector is connected in series at the lower end of the resistor chip samples to collect the current passing through the resistor chips in real time. Combining the voltage measurement data, the resistance value of the resistor chips and its variation law with temperature can be accurately calculated. An adjustable resistor box is connected in parallel at both ends of the resistor chip samples. By adjusting the resistance value of the adjustable resistor box, the total resistance in the circuit can be flexibly changed, thereby realizing the precise control of the current and voltage in the circuit. The present invention facilitates obtaining different temperatures by placing the resistor chip samples in the temperature simulation box, can obtain the voltage under currents from dozens of milliamperes to dozens of amperes by adding an adjustable resistor box, and further obtains the resistance change trend and the positive and negative temperature coefficient turning points of the samples at different temperatures, providing an important basis for the selection of arrester parameters. Description of the Drawings

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0017] Figure 1 It is the circuit schematic diagram of the present invention; Figure 2 It is the structural schematic diagram of the adjustable resistor box of the present invention; Figure 3 It is the structural schematic diagram of the temperature simulation box of the present invention.

[0018] Wherein: 1 - resistor chip sample; 2 - resistor chip sample box; 3 - adjustable resistor box; 4 - shunt resistor chip; 5 - parallel capacitor; 6 - loop inductance; 7 - loop resistance; 8 - ignition spark gap; 9 - current collector; 10 - voltage divider; 11 - temperature simulation box. Detailed implementation manners

[0019] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated in the accompanying drawings here can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0021] It should be noted that like reference numerals and letters denote like items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0022] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper", "lower", "horizontal", "inner", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, or the orientations or positional relationships in which the products of the invention are usually placed during use, it is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated devices or elements must have specific orientations, be constructed and operated in specific orientations, and therefore should not be construed as limiting the present invention. In addition, terms such as "first", "second", etc. are only used for descriptive distinction and cannot be construed as indicating or implying relative importance.

[0023] In addition, if the term "horizontal" appears, it does not mean that the component is required to be absolutely horizontal, but it can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but it can be slightly inclined.

[0024] In the description of the embodiments of the present invention, it should also be noted that unless otherwise clearly specified and limited, if terms such as "set", "installed", "connected", "connected" are understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] The present invention will be further described in detail below with reference to the accompanying drawings: Referring to Figure 1 , an embodiment of the present invention discloses a device for measuring the temperature characteristics of a resistor chip, which includes a loop inductor 6, a loop resistor 7, a spark gap 8, a resistor chip specimen 1 connected in series in sequence, and a parallel capacitor 5; the resistor chip specimen 1 is arranged in a temperature simulation box 11 capable of adjusting temperature; both ends of the resistor chip specimen 1 are connected in parallel with an adjustable resistor box 3; a voltage divider 10 is also connected in parallel at both ends of the resistor chip specimen 1 for voltage measurement; the resistor chip specimen 1 is connected in series with a current collector 9 for current measurement. This device simulates the resistance change trend of the resistor chip under different temperatures and different waveforms by the charge and discharge of the parallel capacitor 5, the discharge of the spark gap 8, and the adjustment of the waveforms by the loop inductor 6 and the loop resistor 7 to determine its temperature coefficient turning point. By measuring the resistance values of the resistor chip under different waveforms and temperatures, a curve of resistance varying with temperature can be plotted. Further analyzing this curve can determine the temperature coefficient turning point of the resistor chip, that is, the point where the rate of change of the resistance value with temperature changes significantly. The determination of this turning point is of great significance for in-depth research on the performance of the resistor chip, optimizing its design, and improving its reliability in practical applications.

[0026] In a feasible embodiment of the present invention, referring to Figure 2 , the adjustable resistor box 3 includes a plurality of shunt resistor chips 4 connected in parallel, and the resistance adjustment is achieved through the combination and switching of the plurality of shunt resistor chips 4. The plurality of shunt resistor chips 4 have the same performance parameters as the resistor chip specimen 1 to be measured.

[0027] In a feasible embodiment of the present invention, referring to Figure 3 , the temperature simulation box 11 includes a sealed box body; outlet bushings are installed on both the top surface and the bottom surface of the sealed box body and are respectively connected to the external high-voltage end and low-voltage end; an insulating platform is installed inside the sealed box body; a resistor chip specimen box 2 is installed on the insulating platform, the resistor chip specimen box 2 is connected to the outlet bushings, and the resistor chip specimen 1 is placed in the resistor chip specimen box 2. The resistor chip specimen box 2 includes an insulating cylinder and copper plates located at both ends of the insulating cylinder; an insulating rod is threadedly connected to the bottom end of the insulating cylinder, and the insulating rod passes through the insulating platform and is connected to the bottom of the sealed box body. In this embodiment, the temperature simulation box 11 adopts a sealed box body design, effectively isolating the interference of the external environment on the temperature inside the box and the resistor chip specimen 1, ensuring the stability and controllability of the experimental environment. This sealing is crucial for accurately simulating and measuring the performance of the resistor chip under different temperature conditions. The resistor chip specimen box 2 adopts a modular design, including an insulating cylinder and copper plates located at both ends of the insulating cylinder, which makes the placement and replacement of the resistor chip specimen 1 very convenient. When it is necessary to replace different specifications or types of resistor chip specimens, only the specimen box needs to be replaced, without major modifications to the entire temperature simulation box.

[0028] In a feasible embodiment of the present invention, the current collector 9 preferably adopts a through-core current transformer with an accuracy of 0.1. The voltage divider 10 preferably adopts a resistive voltage divider.

[0029] The embodiment of the present invention discloses a method for measuring the temperature characteristics of a resistor chip. Based on the above device for measuring the temperature characteristics of a resistor chip, it includes the following steps: Step 1, select resistor chips with the same batch performance parameters as the resistor chip sample 1 to be measured, conduct a current sharing test, and select the resistor chip with a current non-uniformity coefficient less than a preset threshold as the shunt resistor chip 4; Step 2, place several selected shunt resistor chips 4 in the adjustable resistor box 3; Step 3, place the resistor chip sample 1 to be measured in the resistor chip sample box 2 in the temperature simulation box 11, and connect the resistor chip sample box 2 to the outgoing line bushing; Step 4, adjust the temperature of the temperature simulation box 11 to heat the resistor chip sample 1; Step 5, realize the pressurization of the resistor chip sample 1 under different waveforms through the combination of charging and discharging of the parallel capacitor 5, discharging of the ignition sphere gap 8, the loop inductor 6 and the loop resistor 7; Step 6, collect the voltage and current values on the resistor chip sample 1 in each test through the voltage divider 10 and the current collector 9.

[0030] The working principle of the present invention is as follows: The present invention provides a device for measuring the temperature characteristics of a resistor chip, which includes a resistor chip specimen 1, a resistor chip specimen box 2, an adjustable resistor box 3, a shunt resistor chip 4, a parallel capacitor 5, a loop inductor 6, a loop resistor 7, an ignition spark gap 8, a current collector 9, a voltage divider 10, and a temperature simulation box 11. The resistor chip specimen box 2 contains the resistor chip specimen 1 to be tested inside, and the adjustable resistor box 3 contains the shunt resistor chip 4 inside. The resistor chip specimen 1 and the shunt resistor chip 4 are connected in parallel to obtain a small current. The resistor chip specimen box 2 is fixed on the insulating platform inside the temperature simulation box 11. The voltage divider 10 is connected in parallel with the resistor chip specimen 1 for voltage measurement, and the current collector 9 is connected in series at the lower end of the resistor chip specimen 1 for current collection. The parallel capacitor 5 for charging and discharging, the ignition spark gap discharge 8, and the loop inductor 6 and loop resistor 7 are connected to the resistor chip specimen 1 through series and parallel connections. The resistor chip specimen box 2 is composed of upper and lower copper plates, an insulating cylinder with threads, and an insulating rod, and test resistor chips can be placed inside. The adjustable resistor box 3 contains hundreds of shunt resistor chips 4 with the same performance parameters as the specimens in the same batch, and the current non-uniformity coefficient between them is less than a preset threshold K. At the same time, according to the required current magnitude, the number of resistor chips 4 inside the adjustable resistor box 3 can be connected by adjusting the wiring method. The temperature simulation box 11 is a sealed box with an adjustable range from room temperature to 150 °C. Its top and bottom are respectively equipped with outgoing line sleeves, which are connected to the external high-voltage end and low-voltage end respectively. An insulating platform is arranged inside the sealed box, and studs are arranged on the insulating platform to fix the resistor chip specimen box 2 on the insulating platform. The present invention facilitates obtaining different temperatures by placing the resistor chip specimen in the temperature simulation box 11, and can obtain the voltage under currents from dozens of milliamperes to dozens of amperes by adding the adjustable resistor box 3, and further obtain the resistance change trend and the positive and negative temperature coefficient turning points of the specimen at different temperatures, providing an important basis for the selection of arrester parameters.

[0031] Embodiment: This embodiment provides a device and method for measuring the temperature characteristics of a resistor chip. The device has the same structure as described above and is implemented according to the following steps: 1) Select D105 resistor chips of the same batch and the same specification as the resistor chip specimen 1 to be measured for the current sharing test. The current sharing test is carried out using an impulse wave, and the current sharing non-uniformity coefficient is less than 2%.

[0032] 2) The resistor chip specimen 1 is connected in parallel with 60 resistor chips through wiring to generate a test current of 2 A.

[0033] 3) Place the D105 resistor chip specimen 1 in the resistor chip specimen box 2, and fasten the resistor chip specimen box 2 on the insulating platform inside the temperature simulation box 11. The upper outgoing line sleeve of the temperature simulation box 11 is connected to the upper end of the specimen box.

[0034] 4) Heat the resistor chip specimen 1 to 120 °C.

[0035] 5) The voltage is applied to the test sample under different waveforms by the combined action of the charge and discharge of the shunt capacitor 5, the discharge of the ignition spark gap 8, and the loop inductance 6 and loop resistance 7.

[0036] 6) Through the voltage divider 10 and the current collector 9, the voltage across the resistor chip under a 2A current can be collected.

[0037] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and variations can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A device for measuring the temperature characteristics of a resistor, characterized in that: The invention comprises a loop inductor (6), a loop resistor (7), an ignition ball gap (8), a resistor sample (1) and a parallel capacitor (5) which are connected in series in sequence; the resistor sample (1) is arranged in a temperature simulation box (11) capable of adjusting the temperature; the two ends of the resistor sample (1) are connected in parallel to an adjustable resistance box (3); the two ends of the resistor sample (1) are also connected in parallel to a voltage divider (10) for voltage measurement; and the resistor sample (1) is connected in series to a current collector (9) for current measurement.

2. A device for measuring the temperature characteristics of a resistor according to claim 1, characterized in that: The adjustable resistance box (3) comprises a plurality of shunt resistors (4) connected in parallel, and resistance adjustment is achieved through the combination and switching of the plurality of shunt resistors (4).

3. The device for measuring the temperature characteristics of a resistor according to claim 2, characterized in that: The performance parameters of the plurality of shunt resistors (4) are consistent with those of the resistor sample (1) to be tested.

4. The device for measuring the temperature characteristics of a resistor according to claim 1, characterized in that: The temperature simulation box (11) comprises a sealed box body; outlet bushings are installed on the top and bottom surfaces of the sealed box body, respectively connected to an external high-voltage end and a low-voltage end; an insulating platform is installed inside the sealed box body; a resistor sample box (2) is installed on the insulating platform, the resistor sample box (2) is connected to the outlet bushings, and a resistor sample (1) is placed inside the resistor sample box (2).

5. The device for measuring the temperature characteristics of a resistor according to claim 4, characterized in that: The resistor test box (2) comprises an insulating tube and copper plates located at both ends of the insulating tube; an insulating rod is threadedly connected to the bottom end of the insulating tube, and the insulating rod passes through the insulating platform and is connected to the bottom of the sealed box.

6. The device for measuring the temperature characteristics of a resistor according to claim 1, characterized in that: The current collector (9) is a core-through type mutual inductor.

7. The device for measuring the temperature characteristics of a resistor according to claim 1, characterized in that: The measurement accuracy of the core-through type mutual inductor is 0.

1.

8. The device for measuring the temperature characteristics of a resistor according to claim 1, characterized in that: The voltage divider (10) is a resistive voltage divider.

9. A method for measuring the temperature characteristics of a resistor, characterized in that: A device for measuring the temperature characteristics of a resistor according to any one of claims 1 to 8, comprising the following steps: Select a number of shunt resistors (4) and place them in the adjustable resistance box (3); Placing a resistor sample (1) to be tested in a resistor sample box (2) in a temperature simulation box (11), and connecting the resistor sample box (2) to an outlet bushing; Adjusting the temperature of the temperature simulation box (11) to heat the resistor sample (1); The resistor sample (1) is pressurized under different waveforms by charging and discharging the parallel capacitor (5), discharging the ignition ball gap (8), and combining the loop inductance (6) and the loop resistance (7); The voltage and current values ​​on the resistor sample (1) in each test are collected through the voltage divider (10) and the current collector (9).

10. A method for measuring the temperature characteristics of a resistor according to claim 9, characterized in that: The step of selecting a plurality of shunt resistors (4) and placing them in the adjustable resistor box (3) specifically comprises: Resistors with the same performance parameters as the resistor sample (1) to be tested are selected from the same batch to perform a current sharing test, and resistors with a current non-uniformity coefficient less than a preset threshold are selected as shunt resistors (4); the selected shunt resistors (4) are placed in an adjustable resistor box (3).

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