A GIS loop resistance measurement device and method

Abstract

The present invention relates to a GIS loop resistance measuring device and method, the device comprises a GIS device (5), a current collection element (9), a super capacitor (2) and a switch element (3) connected in sequence, the super capacitor (2) is connected to a charger (1), the GIS device (5) is connected to a voltage collection element (8), the GIS device (5), the current collection element (9), the super capacitor (2) and the switch element (3) constitute a main discharge circuit of the device, the device also comprises a discharge branch (4), the discharge branch (4) is connected in parallel with the GIS device (5) and the current collection element (9) to constitute a sub-discharge circuit. Compared with the prior art, the present invention has the advantages of high accuracy and high efficiency.

Description

Technical Field

[0001] The present invention relates to a GIS state assessment technology, and in particular to a GIS loop resistance measurement device and method. Background Art

[0002] Gas Insulated Switchgear (GIS) has the advantages of small footprint, low failure probability, high safety performance, low environmental impact, and easy installation and maintenance, which can greatly improve the reliability of power supply. GIS may cause poor internal electrical contact due to problems in the materials, assembly process, equipment transportation and installation of its equipment. The conductive loop resistance of GIS has always been an important technical indicator for evaluating the quality and operating status of equipment. The test items for measuring the GIS loop resistance are specified in the relevant national standards and industry standards. Through actual measurement, it is determined whether the conductive loop resistance value is within the allowable range to check the equipment installation quality and the integrity of the loop, and to find the defect of poor contact early, so as to ensure the ability of GIS equipment to carry current for a long time and pass the limiting current during short circuit. In engineering applications, the traditional method for measuring the conductive loop resistance of GIS is the DC method, which applies a DC current greater than or equal to 100A to the conductive loop, measures the loop voltage drop, and obtains the loop resistance value. Due to the difference between the DC measurement state and the AC operation state of the conductive connector, this method has defects.

[0003] The prior art also provides some solutions. Chinese patent CN201310131893.9 proposes a method for measuring the electrical parameters of a GIS conductive loop. A second-order non-oscillating circuit is used to generate a kiloampere-level impulse current. The voltage drop signal of the standard resistor and the GIS conductive rod is collected through a voltage isolation sensor to obtain the impulse current peak value, that is, the instantaneous current value at the moment when the current change rate is zero and the voltage drop of the conductive connector at the corresponding moment. The loop resistance is measured to eliminate the influence of the conductive rod inductance component on the loop resistance measurement. On the basis of accurately measuring the loop resistance, the slope of the impulse current is extracted, and the inductance of the GIS conductive rod is measured according to the corresponding conductive rod voltage drop.

[0004] However, this patent has the following problems:

[0005] After the capacitor is fully charged, it is discharged to generate an impact current, obtain the current waveform and voltage drop waveform of the GIS conductive rod, and calculate the loop resistance of the GIS conductive rod once. After that, the capacitor needs to be charged again before the next measurement can be continued. The measurement efficiency is low, the data sample for one measurement is small, and the error of a single test result is relatively large. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a GIS loop resistance measurement device and method with high accuracy and high efficiency.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] A GIS loop resistance measuring device comprises a supercapacitor, a switch element, a current collection element, a voltage collection element, and a discharge branch. The GIS equipment, the current collection element, the supercapacitor, and the switch element are connected in sequence to form a main discharge circuit. The switch element is connected to a controller to control the on and off of the switch element. The supercapacitor is connected to a charger. The voltage collection element is connected to the GIS equipment. The discharge branch comprises a discharge resistor. The discharge branch is connected in parallel with the GIS equipment and the current collection element to form a sub-discharge circuit. The current collection element collects current signals, and the voltage collection element collects voltage signals at both ends of the GIS equipment.

[0009] The charger charges the supercapacitor to a set value and then stops charging; then the switch element is turned on, the main discharge circuit is turned on, the supercapacitor discharges the main discharge circuit, generates an impact current, and the voltage of the supercapacitor decreases; when the set conditions are met, such as the current passing through the GIS device reaches a peak value and then drops to the set value or the duration reaches the set time, the switch element is cut off, and the inductance of the GIS circuit discharges the sub-discharge circuit; when the repeated measurement conditions are met, such as the supercapacitor voltage is higher than the set value or the number of measurements is less than the set value, the switch element is turned on again, and the supercapacitor continues to discharge the main discharge circuit; when the set conditions are met, the switch element is turned off, and the inductance of the GIS circuit discharges the sub-discharge circuit; the cyclic discharge process of the main discharge circuit and the sub-discharge circuit is continued for multiple times, and the measurement ends when the repeated measurement set conditions are not met. The addition of a discharge branch enables the supercapacitor to obtain loop resistance values ​​under multiple current values ​​after charging once, and the change of the loop resistance value with the current can be obtained, which improves the measurement efficiency of the loop resistance, reduces the measurement error, and has high accuracy of the test results. The data sample volume for judging the contact state of the circuit is increased, and the judgment accuracy is improved.

[0010] Furthermore, the switching element is an IGBT, which has high withstand voltage, low on-state voltage and fast switching speed.

[0011] Furthermore, the controller is connected to an acquisition card, which is connected to the voltage acquisition element and the current acquisition element, and the controller controls the acquisition card to acquire current and voltage signals.

[0012] Furthermore, the current collection element is a Rogowski coil.

[0013] Furthermore, the voltage acquisition element is a voltage differential probe.

[0014] A measurement method using the GIS loop resistance measurement device is specifically as follows:

[0015] S1: the switch element is disconnected, the charger charges the supercapacitor, and the supercapacitor is disconnected from the charger after being fully charged;

[0016] S2: The switch element is turned on, the supercapacitor discharges the main discharge loop, the current acquisition element and the voltage acquisition element respectively collect the current signal and the voltage signal of the GIS device, the current passing through the GIS device reaches the peak value, and the loop resistance of the GIS device is calculated according to the current and voltage. When the set conditions are met, the switch element is disconnected, the inductor in the GIS device discharges the sub-discharge loop, and the loop resistance of the GIS device is calculated again;

[0017] S3: When the repeated measurement condition is met, step S2 is repeated to achieve multiple measurements of the loop resistance of the GIS equipment; otherwise, the measurement ends.

[0018] Furthermore, the setting condition is any one of the following:

[0019] The current passing through the GIS equipment passes a peak value and then drops to the set value;

[0020] The current passing through the GIS equipment reaches a peak value and lasts for a set period of time.

[0021] Furthermore, the repeated measurement condition is any one of the following:

[0022] The voltage of the supercapacitor is higher than the set value;

[0023] The number of measurements is less than the set value.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The present invention sequentially connects GIS equipment, current collection elements, supercapacitors and switch elements to form a main discharge circuit. The supercapacitor is connected to a charger, and the GIS equipment is connected to a voltage collection element. The GIS equipment and the current collection element are also connected in parallel with a discharge branch, which forms a sub-discharge circuit with the GIS equipment and the current collection element. After the supercapacitor is charged once, the switch element is turned on, and the supercapacitor discharges the main discharge circuit once. After the switch element is turned off, the inductor in the GIS equipment discharges the sub-discharge circuit once. When the supercapacitor voltage is higher than the set value or the number of measurements is less than the set value, the switch element is turned on again, and the supercapacitor continues to discharge the main discharge circuit. The cycle is repeated as above. After the supercapacitor is charged once, the loop resistance values ​​under multiple current values ​​can be obtained, which facilitates the acquisition of the change of the loop resistance value with the current, improves the measurement efficiency of the loop resistance, reduces the measurement error, and has high accuracy of the test results. The data sample volume for judging the contact state of the loop is increased, and the accuracy of the judgment is improved.

[0026] (2) The present invention uses IGBT as a switching element, which has high withstand voltage, low on-state voltage and fast switching speed;

[0027] (3) The present invention adopts Rogowski coil to collect high frequency and large current, has good linearity, is easy to install, and has no risk of secondary open circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A circuit topology diagram of the present invention;

[0029] Figure 2 It is a simulation circuit diagram of the present invention;

[0030] Figure 3 This is a curve diagram of the supercapacitor voltage changing with time within 0.1s;

[0031] Figure 4 It is a curve diagram of the current passing through the GIS circuit changing with time within 0.1s;

[0032] Figure 5 It is a curve diagram of the voltage change of GIS circuit over time within 0.1s;

[0033] Figure 6 This is the change diagram of the loop resistance value within 0.1s;

[0034] Figure 7 It is a curve diagram of the supercapacitor voltage changing with time within 1s;

[0035] Figure 8 It is a curve diagram of the current passing through the GIS circuit changing with time within 1 second;

[0036] Fig. 9It is a curve diagram of the voltage change of the GIS circuit over time within 1s;

[0037] Fig.10 This is the change diagram of the loop resistance value within 1s;

[0038] Description of the numbers in the figure:

[0039] 1. Charger, 2. Supercapacitor, 3. Switching element, 4. Discharge branch, 5. GIS equipment, 6. Controller, 7. Acquisition card, 8. Voltage acquisition element, 9. Current acquisition element. DETAILED DESCRIPTION

[0040] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0041] Example 1

[0042] A GIS loop resistance measuring device, such as Figure 1 It includes a supercapacitor 2, a switch element 3, a voltage acquisition element 8, a current acquisition element 9, a discharge branch 4 and a controller 6. The GIS device 5, the current acquisition element 9, the supercapacitor 2 and the switch element 3 are connected in sequence to form a main discharge circuit. The supercapacitor 2 is connected to a charger 1. The voltage acquisition element 8 is connected to the GIS device 5. The discharge branch 4 is connected in parallel with the GIS device 5 and the current acquisition element 9 to form a sub-discharge circuit. The controller 6 is connected to the switch element 3 to send a trigger signal to the switch element 3. The industrial computer is connected to an acquisition card 7. The acquisition card 7 is connected to the voltage acquisition element 8 and the current acquisition element 9 to collect voltage signals and current signals. The current acquisition element 9 adopts a Rogowski coil, and the voltage acquisition element 8 is a voltage differential probe with a model of KEYSIGHT N2791A.

[0043] The simulation circuit diagram is as follows Figure 2 As shown, the capacitance of supercapacitor 2 is 165F, and the internal resistance R in The resistance R of the GIS device 5 is 0.0001Ω, the inductance L is 1μH, the sampling rate of the acquisition card 7 is set to 200kHz, and the discharge branch 4 adopts R f , R f When the IGBT is turned off, R f, R and L form a loop, and L discharges. When the current on the GIS device 5 passes a peak and drops by 100A, the controller 6 turns off the IGBT, the main discharge loop is disconnected, and the inductor L discharges through the sub-discharge loop. When the current in the sub-discharge loop drops to 100A, the industrial computer controls the IGBT module to turn on again, the main discharge loop is turned on, and the supercapacitor 2 discharges the GIS device 5 again. The sampling rate of the acquisition card 7 remains unchanged, the Rogowski coil collects the real-time waveform of the current, and the voltage differential probe collects the real-time waveform of the voltage. The voltage change curve of the supercapacitor 2 within 0.1s is shown in the figure below. Figure 3 As shown, the current variation curve of the GIS device 5 within 0.1s is as follows Figure 4 As shown, the voltage variation curve of GIS equipment 5 within 0.1s is as follows Figure 5 As shown, Figure 6 The R resistance value calculated when the current value passing through the GIS device 5 reaches the extreme point, and the voltage change curve of the supercapacitor 2 within 1s is as follows: Figure 7 As shown, the current variation curve of the GIS device 5 within 1s is as follows Figure 8 As shown, the voltage variation curve of GIS equipment 5 within 1s is as follows Fig. 9 As shown, Fig.10 It is the R resistance value calculated when the current value passing through the GIS device 5 reaches the extreme point within 1s. The rate of change of resistance with current is used to judge whether the contact of the GIS device 5 is good. The greater the rate of change of resistance with current, the worse the contact. When it exceeds the set value, it is determined that the GIS device 5 has poor contact.

[0044] For GIS device 5, multiple on-off measurements can reduce errors. The trend of the measured contact resistance changing with current can also be studied. The curve of resistance changing with current can be used to determine the resistance. The simulation setting here is a resistance R of 0.0001Ω, and the error comes from the sampling frequency, etc.

[0045] Example 2

[0046] A GIS loop resistance measurement method corresponding to Example 1 is specifically as follows:

[0047] S1: Switching element 3 is disconnected, charger 1 charges supercapacitor 2, and after full charge, supercapacitor 2 is disconnected from charger 1;

[0048] S2: The switch element 3 is turned on, the supercapacitor 2 discharges the main discharge loop, the current acquisition element 9 and the voltage acquisition element 8 respectively collect the current signal and the voltage signal of the GIS device 5, the current through the GIS device 5 reaches the peak value, and the loop resistance of the GIS device is calculated according to the current and voltage. When the set conditions are met, the switch element 3 is disconnected, the inductor in the GIS device 5 discharges the sub-discharge loop, and the loop resistance of the GIS device is calculated again;

[0049] S3: When the repeated measurement condition is met, step S2 is repeated to achieve multiple measurements of the loop resistance of the GIS equipment; otherwise, the measurement ends.

[0050] Set the condition to any of the following:

[0051] The current passing through the GIS device 5 passes through a peak value and then drops to a set value;

[0052] The current passing through the GIS device 5 reaches a peak value and lasts for a set time.

[0053] The repeated measurement conditions are any of the following:

[0054] The voltage of supercapacitor 2 is higher than the set value;

[0055] The number of measurements is less than the set value.

[0056] Embodiment 1 and embodiment 2 propose a GIS loop resistance measurement device and method. The supercapacitor 2 can obtain the loop resistance value of the GIS equipment 5 under multiple current values ​​after being charged once, which is convenient for obtaining the change of the loop resistance value with the current, improves the measurement efficiency of the loop resistance, reduces the measurement error, has high accuracy of the test results, increases the data sample size for judging the contact status of the loop, and improves the accuracy of the judgment.

[0057] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A GIS loop resistance measurement method, implemented by using a GIS loop resistance measurement device, the GIS loop resistance measurement device comprising a GIS device (5), a current collection element (9), a super capacitor (2) and a switch element (3) connected in sequence, the switch element (3) being connected to a controller (6), the super capacitor (2) being connected to a charger (1), and the GIS device (5) being connected to a voltage collection element (8), characterized in that: The measuring device further comprises a discharge branch (4); the GIS device (5), the current collection element (9), the super capacitor (2) and the switch element (3) constitute a main discharge circuit of the device; the discharge branch (4) is connected in parallel with the GIS device (5) and the current collection element (9) to constitute a sub-discharge circuit; The measuring method is: S1: the switch element (3) is disconnected, the charger (1) charges the supercapacitor (2), and after the supercapacitor (2) is fully charged, the supercapacitor (2) is disconnected from the charger (1); S2: the controller (6) controls the switch element (3) to be turned on, the supercapacitor (2) discharges the main discharge circuit, the current acquisition element (9) and the voltage acquisition element (8) respectively collect the current signal and the voltage signal of the GIS device (5), the current passing through the GIS device (5) reaches a peak value, and the loop resistance of the GIS device is calculated based on the current and the voltage. When the set conditions are met, the controller (6) controls the switch element (3) to be turned off, the inductor in the GIS device (5) discharges the sub-discharge circuit, and the loop resistance of the GIS device is calculated again; S3: When the repeated measurement condition is met, step S2 is repeated to achieve multiple measurements of the loop resistance of the GIS equipment, otherwise the measurement ends.

2. A GIS loop resistance measurement method according to claim 1, characterized in that: The controller (6) is connected to a data acquisition card (7), and the data acquisition card (7) is connected to a voltage acquisition element (8) and a current acquisition element (9).

3. A GIS loop resistance measurement method according to claim 1, characterized in that: The switching element (3) is an IGBT.

4. A GIS loop resistance measurement method according to claim 3, characterized in that: The IGBT is AUIRGDC0250.

5. A GIS loop resistance measurement method according to claim 1, characterized in that: The current collection element (9) is a Rogowski coil.

6. A GIS loop resistance measurement method according to claim 1, characterized in that: The voltage collection element (8) is a voltage differential probe.

7. A GIS loop resistance measurement method according to claim 6, characterized in that: The model of the voltage differential probe is KEYSIGHT N2791A.

8. A GIS loop resistance measurement method according to claim 1, characterized in that: The setting condition is any one of the following: The current passing through the GIS device (5) passes through a peak value and then drops to a set value; The current passing through the GIS device (5) reaches a peak value and lasts for a set period of time.

9. A GIS loop resistance measurement method according to claim 1, characterized in that: The repeated measurement condition is any one of the following: The voltage of the supercapacitor (2) is higher than a set value; The number of measurements is less than the set value.

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