Method for calibrating a sulfur hexafluoride density relay

Abstract

The present application relates to a kind of sulfur hexafluoride density relay verification method, comprising the following steps: being connected with the test loop of DC power supply by being calibrated relay, the output voltage of DC power supply is set as first test voltage;Using oscilloscope acquisition calibrated relay's electrical contact voltage, while collecting the current value of test loop, according to the voltage value of the oscilloscope and the current value of test loop, judge the open-close state of calibrated relay, if it is off state, then perform downlink verification, if it is closed state, then perform uplink verification;In downlink verification, reduce the pressure of calibrated relay, based on the voltage value of the oscilloscope and the current value of test loop, judge whether calibrated relay is normal action based on the change situation;In uplink verification, increase the pressure of calibrated relay, based on the voltage value of the oscilloscope and the current value of test loop, judge whether calibrated relay is normal action based on the change situation.Compared with prior art, the present application has the advantages of high accuracy, reduce misjudgment etc..

Description

Technical Field

[0001] This invention relates to the field of power equipment testing technology, and in particular to a method for calibrating a sulfur hexafluoride density relay. Background Technology

[0002] Using sulfur hexafluoride (SF6) gas as the insulating medium in Class I GIS high-voltage switchgear effectively reduces the overall size, improves the arc-extinguishing capability of the break, and enhances the safety of the equipment. However, preventing SF6 gas leakage in a sealed state has always been a challenge. In engineering practice, SF6 gas density relays are installed in the gas chamber storing SF6. By monitoring changes in internal pressure, leaks are detected and warned of. The performance of these relays directly affects the reliable and safe operation of SF6 electrical equipment. According to technical supervision regulations, the SF6 gas density relays must be calibrated regularly.

[0003] During field calibration of sulfur hexafluoride density relays, faults such as relay failure to conduct are common. Research has revealed that some of these failures are indeed due to poor contact between electrical contacts or the influence of oil film and impurities on conductivity, while others are misjudgments caused by incomplete sampling by the calibration instrument. To address this issue in existing calibration methods, a new, accurate, and effective testing method for sulfur hexafluoride density relays is needed. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a highly accurate sulfur hexafluoride density relay calibration method that reduces misjudgments.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for calibrating a sulfur hexafluoride density relay includes the following steps:

[0007] Connect the relay to be calibrated to a DC power supply to form a test circuit, and set the output voltage of the DC power supply as the first test voltage;

[0008] The voltage of the electrical contacts of the relay under test is acquired using an oscilloscope, and the current value of the test circuit is acquired at the same time. The open and closed state of the relay under test is determined based on the voltage value of the oscilloscope and the current value of the test circuit. If it is in the open state, the downlink verification is performed; if it is in the closed state, the uplink verification is performed.

[0009] In the downlink verification, the pressure on the relay under test is reduced, and the relay under test is judged to be operating normally based on the changes in the voltage value of the oscilloscope and the current value of the test circuit.

[0010] In the uplink verification, the pressure on the relay under test is increased, and the relay under test is judged to be operating normally based on the changes in the voltage value of the oscilloscope and the current value of the test circuit.

[0011] Furthermore, determining the open / closed state of the relay under test based on the voltage value of the oscilloscope and the current value of the test circuit specifically involves:

[0012] When the voltage value on the oscilloscope is the output voltage of the DC power supply, and the current value of the test circuit is 0, it is judged to be in an open state.

[0013] When the voltage value of the oscilloscope is 0 and there is a certain current value in the test circuit, it is judged to be in a closed state.

[0014] Furthermore, in the downlink verification, the pressure on the relay being verified is reduced until the voltage value of the oscilloscope fluctuates and then stabilizes at a certain value before stopping.

[0015] Furthermore, in the downlink verification, determining whether the relay being verified is operating normally specifically involves:

[0016] If the voltage value on the oscilloscope fluctuates and then becomes 0, and at the same time a certain current value is generated in the test circuit, then the relay under test is determined to be operating normally.

[0017] If the voltage value on the oscilloscope fluctuates and becomes a non-zero value, and at the same time a certain current value is generated in the test circuit, then it is determined that the relay under test has a poor contact defect.

[0018] If the voltage value of the oscilloscope fluctuates and becomes the output voltage of the DC power supply, and the current value of the test circuit is 0, then it is determined that the relay being calibrated is not conducting.

[0019] Furthermore, in the uplink verification, the pressure on the relay being verified is increased until the voltage value of the oscilloscope fluctuates and then stabilizes at a certain value before stopping.

[0020] Furthermore, in the uplink verification, determining whether the relay being verified is operating normally specifically involves:

[0021] If the voltage value of the oscilloscope fluctuates and becomes the output voltage of the DC power supply, and the current value of the test circuit is 0, then the relay under test is determined to be operating normally.

[0022] If the voltage value of the oscilloscope bounces too many times during the process of becoming the output voltage of the DC power supply, then the relay being calibrated is considered to be faulty.

[0023] Furthermore, the pressure of the relay being calibrated can be reduced or increased using an SF6 pressure controller.

[0024] Furthermore, the SF6 pressure controller is connected to the relay being calibrated via a gas pipeline.

[0025] Furthermore, the current value of the acquisition test circuit is obtained using a milliampere-level ammeter.

[0026] Furthermore, the method also includes:

[0027] Adjust the output voltage of the DC power supply to the second test voltage, and repeat the downlink and uplink verification.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. This invention uses an oscilloscope to collect real-time data on changes in electrical contact voltage. By observing the real-time voltage data collected by the oscilloscope, the change in the opening and closing state can be determined. At the same time, the current value in the test circuit is used to assist in the judgment of the opening and closing state. Through double confirmation, the opening and closing state of the sulfur hexafluoride density relay can be accurately determined. Based on this, the action value of the relay can be accurately recorded, reducing misjudgments.

[0030] 2. This invention can accurately distinguish between conduction faults and increased resistance caused by poor contact in the relay being calibrated by collecting changes in oscilloscope voltage and test circuit current values, making it highly targeted for accurate status identification. Attached Figure Description

[0031] Figure 1 This is the waveform that an oscilloscope may display during the downlink verification of this invention;

[0032] Figure 2 This is a schematic diagram of the verification process during the downlink verification of the present invention;

[0033] Figure 3 This is the waveform that an oscilloscope may display during the uplink verification of this invention;

[0034] Figure 4 This is a schematic diagram of the verification process during the uplink verification of this invention. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0036] This embodiment provides a method for calibrating a sulfur hexafluoride density relay, including the following steps: connecting the relay to be calibrated to a DC power supply to form a test circuit, and setting the output voltage of the DC power supply as a first test voltage; using an oscilloscope to acquire the electrical contact voltage of the relay to be calibrated, and simultaneously acquiring the current value of the test circuit; determining the open / closed state of the relay to be calibrated based on the voltage value of the oscilloscope and the current value of the test circuit; if it is in an open state, performing a downward calibration; if it is in a closed state, performing an upward calibration; in the downward calibration, reducing the pressure on the relay to be calibrated, and determining whether the relay to be calibrated operates normally based on the changes in the voltage value of the oscilloscope and the current value of the test circuit; in the upward calibration, increasing the pressure on the relay to be calibrated, and determining whether the relay to be calibrated operates normally based on the changes in the voltage value of the oscilloscope and the current value of the test circuit.

[0037] In the above method, the identification of the open / closed state of the sulfur hexafluoride density relay specifically involves: using an oscilloscope to collect real-time data on changes in the electrical contact voltage; observing the real-time voltage data collected by the oscilloscope to determine the change in the open / closed state; and simultaneously using the current value in the test circuit to assist in the determination of the open / closed state. This double confirmation improves the accuracy of the inspection. This invention can accurately distinguish between situations such as poor contact, increased resistance, and incomplete sampling in the sulfur hexafluoride density relay.

[0038] In this specific implementation, the DC power supply uses an adjustable test voltage, with an adjustment range between 24V and 110V. The pressure of the relay under test is increased or decreased using an SF6 pressure controller connected to the relay via a gas pipeline. The current value of the test circuit is obtained using a milliampere-level ammeter.

[0039] In this embodiment, the implementation process of the above method includes:

[0040] 1. Experimental System Setup

[0041] Connect the DC power supply and the relay to be calibrated to form a test circuit → Connect a current-limiting resistor in the test circuit → Connect a milliampere ammeter in the test circuit → Connect the signal line of the meter to be calibrated to an oscilloscope to measure the voltage value of the relay to be calibrated → Connect the gas pipeline of the SF6 pressure controller and the relay to be calibrated.

[0042] 2. Downlink verification

[0043] Set the DC power supply output voltage to 24V, turn on the calibrator and DC power supply. If the meter is normal, the oscilloscope voltage value will be the DC power supply output voltage, and the ammeter reading will be 0. Start the SF6 pressure controller to reduce the pressure of the meter being calibrated, and simultaneously observe the changes in the voltage value on the oscilloscope and the current value on the ammeter. When the voltage value fluctuates and then stabilizes at a certain value, observe whether the ammeter reading shows any value. When both the voltage and current change, determine that the state of the sulfur hexafluoride density relay has changed. This can be determined according to... Figure 2 The process shown determines the status of the meter being calibrated.

[0044] like Figure 1 and Figure 2 As shown in (1a), if the voltage value of the oscilloscope fluctuates and then becomes 0, and a certain current value is generated in the test circuit, then the relay under test is determined to be operating normally, and the operating value is recorded at this time; if the voltage value of the oscilloscope fluctuates and then becomes a non-zero value, as shown in (1b), and a certain current value is generated in the test circuit, then the resistance of the electrical contact is increased due to poor contact, oil film, etc., the pressure value is recorded, and the relay under test is determined to have a poor contact defect; if the voltage value of the oscilloscope fluctuates and then becomes the output voltage of the DC power supply, as shown in (1c), and the current value of the test circuit is 0, then the relay under test is determined to be non-conductive (i.e. not closed), and there is a fault.

[0045] 3. Uplink verification

[0046] Turn on the calibrator and DC power supply. If the meter is normal, the oscilloscope voltage will be 0, and the ammeter will show a certain reading. Start the SF6 pressure controller to increase the pressure of the meter being calibrated, and simultaneously observe the changes in the voltage value on the oscilloscope and the current value on the ammeter. When the voltage value fluctuates and then stabilizes at a certain value, observe whether the ammeter reading is 0. When both the voltage and current change, determine that the state of the sulfur hexafluoride density relay has changed. This can be determined according to... Figure 4 The process shown determines the status of the meter being calibrated.

[0047] like Figure 3 and Figure 4 As shown in (3a), if the voltage value of the oscilloscope fluctuates and then becomes the output voltage of the DC power supply, and the current value of the test circuit is 0, then the relay under test is determined to be operating normally, and the operating value at this time is recorded. If there are too many bounces during the process of the voltage value of the oscilloscope fluctuating and becoming the output voltage of the DC power supply, as shown in (3b), then the relay under test is determined to be faulty. When the electrical contact changes from the closed position to the open position, a discharge arc is generated between the electrical contacts, and the arc cannot be extinguished quickly, resulting in too many bounces. This problem will cause the background system to misjudge the operation of the electrical contacts.

[0048] 4. Defect handling

[0049] To address the issue of increased contact resistance due to poor contact or oil film during downlink calibration, this test method provides a follow-up test measure: increasing the DC power supply voltage to 110V and repeating both downlink and uplink calibrations to obtain the calibration results at 110V. Increasing the DC power supply voltage to 110V makes it easier for the oil film or oxide layer between the contacts to break down due to the increased voltage. After the oil film or oxide layer is broken down, the contact performance can be restored.

[0050] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for calibrating a sulfur hexafluoride density relay, characterized in that, Includes the following steps: Connect the relay to be calibrated to a DC power supply to form a test circuit, and set the output voltage of the DC power supply as the first test voltage; The voltage of the electrical contacts of the relay under test is acquired using an oscilloscope, and the current value of the test circuit is acquired at the same time. The open and closed state of the relay under test is determined based on the voltage value of the oscilloscope and the current value of the test circuit. If it is in the open state, the downlink verification is performed; if it is in the closed state, the uplink verification is performed. In the downlink verification, the pressure on the relay under test is reduced until the voltage value of the oscilloscope fluctuates and stabilizes at a certain value before stopping. Based on the changes in the voltage value of the oscilloscope and the current value of the test circuit, it is determined whether the relay under test is operating normally. In the uplink verification, the pressure on the relay under test is increased until the voltage value of the oscilloscope fluctuates and stabilizes at a certain value before stopping. Based on the changes in the voltage value of the oscilloscope and the current value of the test circuit, it is determined whether the relay under test is operating normally. In the downlink verification, determining whether the relay being verified is operating normally specifically involves: If the voltage value on the oscilloscope fluctuates and then becomes 0, and at the same time a certain current value is generated in the test circuit, then the relay under test is determined to be operating normally. If the voltage value on the oscilloscope fluctuates and becomes a non-zero value, and at the same time a certain current value is generated in the test circuit, then it is determined that the relay under test has a poor contact defect. If the voltage value of the oscilloscope fluctuates and becomes the output voltage of the DC power supply, and the current value of the test circuit is 0, then it is determined that the relay under test is not conducting. In the uplink verification, determining whether the relay being verified is operating normally specifically involves: If the voltage value of the oscilloscope fluctuates and becomes the output voltage of the DC power supply, and the current value of the test circuit is 0, then the relay under test is determined to be operating normally. If the voltage value of the oscilloscope bounces too many times during the process of becoming the output voltage of the DC power supply, then the relay being calibrated is considered to be faulty.

2. The sulfur hexafluoride density relay calibration method according to claim 1, characterized in that, The specific steps for determining the open / closed state of the relay under test based on the voltage value of the oscilloscope and the current value of the test circuit are as follows: When the voltage value on the oscilloscope is the output voltage of the DC power supply, and the current value of the test circuit is 0, it is judged to be in an open state. When the voltage value of the oscilloscope is 0 and there is a certain current value in the test circuit, it is judged to be in a closed state.

3. The sulfur hexafluoride density relay calibration method according to claim 1, characterized in that, The pressure of the relay being calibrated can be reduced or increased using an SF6 pressure controller.

4. The sulfur hexafluoride density relay calibration method according to claim 3, characterized in that, The SF6 pressure controller is connected to the relay being calibrated via a gas pipeline.

5. The sulfur hexafluoride density relay calibration method according to claim 1, characterized in that, The current value of the acquisition test circuit is obtained using a milliampere ammeter.

6. The sulfur hexafluoride density relay calibration method according to claim 1, characterized in that, The method also includes: Adjust the output voltage of the DC power supply to the second test voltage, and repeat the downlink and uplink verification.

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