Lightning arrester detection method for automatically detecting loaded current-limiting resistor

Abstract

The invention discloses a lightning arrester detection method for automatically detecting and loading a current-limiting resistor, and the method comprises the following specific steps: connecting a plurality of detection units in parallel, each detection unit being connected to a DC high-voltage measurement and control unit, each detection unit comprising a detected lightning arrester, a microammeter and an automatic detection and loading current-limiting resistor unit which are sequentially connected in series; the direct-current high-voltage measurement and control unit outputs a direct-current high-voltage signal, the direct-current high-voltage signal passes through the lightning arrester to be detected, and the microammeter records a current signal of the lightning arrester to be detected; a current signal enters a detection unit, and whether a current-limiting resistor is loaded in the detection unit is judged. According to the invention, the plurality of detection units and the automatic detection loading current-limiting resistor unit are arranged, so that the reference voltage and leakage current of a plurality of sections of detected lightning arresters are automatically detected at one time, and the detection efficiency of the lightning arresters is greatly improved; meanwhile, the influence caused by the reference voltage difference of multiple sections of lightning arresters to be detected is eliminated, and the situation that the lightning arresters are easy to age due to overlarge current in the detection process is prevented.

Description

Technical Field

[0001] The invention relates to the field of lightning arrester detection, and in particular to a lightning arrester detection method for automatically detecting a loaded current limiting resistor. Background Art

[0002] The leakage current of a metal oxide arrester is an important indicator of its quality. The DC 1mA voltage is U 1mA and 0.75U 1mA The leakage current is two important parameters for judging the insulation characteristics of gapless metal oxide arresters. 1mA and 0.75U 1mA The change of leakage current can directly reflect the aging and deterioration degree of the arrester.

[0003] At present, the leakage current detection of lightning arresters is generally carried out by removing the high-voltage lead. The specific process is as follows: after removing the high-voltage lead at the top of the lightning arrester, the tester needs to use a lift or escalator to climb up, connect the high-voltage end of the DC generator to the top of the upper lightning arrester, and ground the bottom of the upper lightning arrester to test the insulation characteristics of the upper lightning arrester; after the test is completed, the high-voltage end of the DC generator and the connection line between the top of the upper lightning arrester and the grounding line at the bottom of the upper lightning arrester are removed, and the high-voltage end of the DC generator is connected to the top of the lower lightning arrester to test the insulation characteristics of the lower lightning arrester. However, this detection method has the following disadvantages: ① Only one lightning arrester is tested each time, which is repetitive and time-consuming; ② During the test, the upper and lower sections of the lightning arrester are measured separately, and the tester needs to climb up many times and repeatedly disassemble and install the leads. The work is relatively dangerous and easy to cause hidden dangers such as lead damage and poor contact of screws.

[0004] In the prior art, for two series-connected lightning arresters, there is also a method of not removing the high-voltage leads, which requires two microammeters to measure simultaneously. However, this test method is slow in increasing and decreasing the voltage and takes too long. Moreover, at least three people are required to read the readings, which has low work efficiency. Summary of the invention

[0005] The present invention provides a lightning arrester detection method for automatically detecting a loaded current limiting resistor. By setting a plurality of detection units and an automatic detection unit for loading a current limiting resistor, the reference voltage and leakage current of multiple sections of the lightning arresters to be tested are automatically detected at one time, thereby greatly improving the lightning arrester detection efficiency. At the same time, the influence caused by the difference in the reference voltage of the multiple sections of the lightning arresters to be tested is eliminated, thereby preventing the occurrence of excessive current during the detection process, which makes the lightning arrester easy to age.

[0006] The technical solution adopted by the present invention is: A lightning arrester detection method for automatically detecting a loaded current limiting resistor comprises the following specific steps: S1, connecting a plurality of detection units in parallel, each detection unit is connected to a DC high voltage measurement and control unit, wherein each detection unit comprises a lightning arrester to be tested, a microammeter and an automatic detection loading current limiting resistor unit connected in series in sequence; S2. The DC high voltage measurement and control unit outputs a DC high voltage signal. The DC high voltage signal passes through the arrester under test, and the microammeter records the current signal of the arrester under test. S3. The current signal enters the detection unit to determine whether a current limiting resistor is loaded in the detection unit: if the rate at which the current of the measured arrester changes with time, that is, the current slope of the measured arrester exceeds the set value, the current limiting resistor is loaded; otherwise, the current limiting resistor is not loaded.

[0007] Furthermore, the automatic detection loading current limiting resistor unit comprises a current slope detection circuit, a relay control circuit and a relay which are sequentially connected in series.

[0008] Furthermore, the process of loading the current limiting resistor in step S3 is as follows: the relay control circuit controls the normally open contact of the relay to connect the current limiting resistor.

[0009] Furthermore, the process of not loading the current limiting resistor in step S3 is as follows: the relay control circuit controls the normally closed contact of the relay to be connected to the current slope detection circuit.

[0010] Compared with the prior art, the present invention has the following beneficial effects: During detection, the present invention connects multiple detection units in parallel to realize one-time simultaneous detection of multiple lightning arresters, greatly improving the detection efficiency of the lightning arresters under test; by setting an automatic detection loading current limiting resistor unit, a current limiting resistor is loaded when the current slope exceeds a set value, thereby eliminating the influence of the reference voltage difference of the multiple lightning arresters under test, and preventing excessive current from occurring during the detection process, which makes the lightning arresters easy to age. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments: Figure 1 It is a flow chart of a method for automatically detecting a lightning arrester loaded with a current limiting resistor according to the present invention; Figure 2 It is a schematic diagram of parallel detection wiring of multi-section lightning arresters in the present invention; Figure 3 It is a circuit principle block diagram of the automatic detection loading current limiting resistor unit in the present invention; Figure 4 It is a schematic diagram of a current slope detection circuit for current variation with time in the present invention. DETAILED DESCRIPTION Example

[0012] like Figure 1A method for automatically detecting a lightning arrester loaded with a current limiting resistor comprises the following specific steps: S1, connecting a plurality of detection units in parallel, each detection unit is connected to a DC high voltage measurement and control unit, wherein each detection unit comprises a lightning arrester to be tested, a microammeter and an automatic detection loading current limiting resistor unit connected in series in sequence; S2. The DC high voltage measurement and control unit outputs a DC high voltage signal. The DC high voltage signal passes through the arrester under test, and the microammeter records the current signal of the arrester under test. S3. The current signal enters the detection unit to determine whether a current limiting resistor is loaded in the detection unit: if the rate at which the current of the measured arrester changes with time, that is, the current slope of the measured arrester exceeds the set value, the current limiting resistor is loaded; otherwise, the current limiting resistor is not loaded.

[0013] Specifically, Figure 2 The figure shows a schematic diagram of parallel detection wiring of multiple lightning arresters, in which the DC high-voltage measurement and control unit outputs a DC high-voltage signal for lightning arrester detection; the detection unit includes a lightning arrester to be tested, a microammeter and an automatic detection loading current limiting resistor unit connected in series in sequence, and the detection unit forms a branch for DC high-voltage signal loading, and several branches are connected in parallel to detect the lightning arrester on each branch, so as to realize simultaneous detection of multiple lightning arresters; in addition, the number of branches depends on the capacity of the DC high-voltage measurement and control unit. Point A in the figure is the current signal after passing through the lightning arrester to be tested; point B is the output current signal after passing through the detection unit.

[0014] Figure 3 The circuit principle block diagram of the automatic detection loading current limiting resistor unit is shown, and the automatic detection loading current limiting resistor unit includes a current slope detection circuit, a relay control circuit and a relay connected in series in sequence; wherein Figure 3 Points A and B are Figure 2 Points A and B in the figure, point D is the output control level after passing through the current slope detection circuit, point a is the normally closed contact of the relay, and point b is the normally open contact of the relay.

[0015] Figure 4 It is the current change rate over time, that is, the current slope detection circuit, where points A and D in the figure are Figure 3 Points A and D in the circuit, and point C is the master control switch. Working principle: U1~U3 are operational amplifiers, and U4 is an AND gate; U1 and its peripheral components R1 and R2 play the role of converting current changes into voltage changes, and U2 and its peripheral components R3 and C0 play the role of converting current slope into voltage, and U3 is a voltage comparator function; the current signal enters from point A, and when point C is at a low level, the current slope detection circuit is locked, and the current slope detection cannot be judged. In addition, when D always outputs a low level, Figure 3 The relay is in the normally closed state; when point C is high level, the current slope detection circuit is turned on, and then Figure 4 U3 output level, Figure 3 The relay control circuit controls the relay to contact point a or b, so that the detection unit is not loaded or loaded with a current limiting resistor, so that the current of the lightning arrester under test will not increase too quickly during the voltage boosting process of the DC high-voltage measurement and control unit.

[0016] The present invention provides a plurality of detection units and an automatic detection loading current limiting resistor unit, and automatically detects the reference voltage and leakage current of multiple sections of the lightning arresters under test at one time, thereby greatly improving the detection efficiency of the lightning arresters; at the same time, the influence caused by the difference in the reference voltage of the multiple sections of the lightning arresters under test is eliminated, and the excessive current is prevented from occurring during the detection process, which makes the lightning arresters easy to age.

[0017] The embodiments described above are merely descriptions of preferred implementation modes of the present invention and are not intended to limit the scope of the present invention. Without departing from the principles and essence of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the scope of protection determined by the claims of the present invention.

Claims

1. A lightning arrester detection method for automatically detecting a loaded current limiting resistor, characterized in that: The specific steps include: S1, connecting a plurality of detection units in parallel, each detection unit is connected to a DC high voltage measurement and control unit, wherein each detection unit comprises a lightning arrester to be tested, a microammeter and an automatic detection loading current limiting resistor unit connected in series in sequence; S2. The DC high voltage measurement and control unit outputs a DC high voltage signal. The DC high voltage signal passes through the arrester under test, and the microammeter records the current signal of the arrester under test. S3. The current signal enters the detection unit to determine whether a current limiting resistor is loaded in the detection unit: if the rate at which the current of the measured arrester changes with time, that is, the current slope of the measured arrester exceeds the set value, the current limiting resistor is loaded; otherwise, the current limiting resistor is not loaded.

2. A lightning arrester detection method for automatically detecting a loaded current limiting resistor according to claim 1, characterized in that: The automatic detection loading current limiting resistor unit comprises a current slope detection circuit, a relay control circuit and a relay which are connected in series in sequence.

3. A lightning arrester detection method for automatically detecting a loaded current limiting resistor according to claim 2, characterized in that: The process of loading the current limiting resistor in step S3 is as follows: the normally open contact of the relay under the control of the relay control circuit is connected to the current limiting resistor.

4. A lightning arrester detection method for automatically detecting a loaded current limiting resistor according to claim 2, characterized in that: The process of not loading the current limiting resistor in step S3 is as follows: the normally closed contact of the relay under the control of the relay control circuit is connected to the current slope detection circuit.

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