An arrester detection method for automatically detecting and loading a current-limiting resistor

Abstract

The present invention discloses a method for detecting a lightning arrester by automatically detecting and loading a current-limiting resistor, which includes the following steps: Connect multiple detection units in parallel, and each detection unit is connected to a DC high-voltage measurement and control unit. Each detection unit includes a lightning arrester under test, a microammeter, and an automatic detection and loading current-limiting resistor unit connected in series in sequence; the DC high-voltage measurement and control unit outputs a DC high-voltage signal, the DC high-voltage signal passes through the lightning arrester under test, and the microammeter records the current signal of the lightning arrester under test; the current signal enters the detection unit to determine whether a current-limiting resistor is loaded in the detection unit. By setting multiple detection units and an automatic detection and loading current-limiting resistor unit, the present invention automatically detects the reference voltage and leakage current of multiple sections of lightning arresters under test at one time, greatly improving the detection efficiency of the lightning arrester; at the same time, eliminating the influence brought by the reference voltage difference of multiple sections of lightning arresters under test and preventing excessive current from occurring during the detection process, which may cause the lightning arrester to age easily.

Description

Technical Field

[0001] The present invention relates to the field of arrester detection. Specifically, it relates to an arrester detection method for automatically detecting and loading a current-limiting resistor. Background Art

[0002] The leakage current of a metal oxide arrester is an important indicator to characterize its quality status. The DC 1 mA voltage, i.e., U 1mA and the leakage current at 0.75U 1mA are two important parameters for judging the insulation characteristics of a gapless metal oxide arrester. After operating for a certain period, the changes in U 1mA and the leakage current at 0.75U 1mA can directly reflect the aging and deterioration degree of the arrester.

[0003] Currently, the general method for detecting the leakage current of an arrester is to remove the high-voltage lead. The specific process is as follows: After removing the high-voltage lead at the top of the arrester, the test personnel need to use an elevated work platform or a ladder to climb high, connect the high-voltage end of the DC generator to the top of the upper section of the arrester, and ground the bottom of the upper section of the arrester to conduct an insulation characteristic test on the upper section of the arrester; after the test is completed, climb high again to remove the connection line between the high-voltage end of the DC generator and the top of the upper section of the arrester and the grounding wire at the bottom of the upper section of the arrester, and connect the high-voltage end of the DC generator to the top of the lower section of the arrester to conduct an insulation characteristic test on the lower section of the arrester. However, this detection method has the following disadvantages: ① Only one section of the arrester is measured each time, with a large amount of repetitive labor and long time consumption; ② During the test process, the upper and lower sections of the arrester are measured separately, and the test personnel need to climb high multiple times, repeatedly disassemble and assemble the leads, and the work is relatively dangerous and prone to hidden dangers such as lead damage and poor screw contact.

[0004] In the prior art, for two series-connected arresters, there is also a method of not removing the high-voltage lead, which requires two microammeter to measure simultaneously. However, with this test method, the voltage increase and decrease are slow, and the time consumption is too long; and at least 3 people are required for reading, resulting in low work efficiency. Summary of the Invention

[0005] The present invention provides an arrester detection method for automatically detecting and loading a current-limiting resistor. By setting multiple detection units and an automatic detection and loading current-limiting resistor unit, the reference voltage and leakage current of multiple sections of the arrester to be measured are automatically detected at one time, greatly improving the arrester detection efficiency; at the same time, eliminating the influence caused by the reference voltage difference of multiple sections of the arrester to be measured, and preventing excessive current from occurring during the detection process, which may cause the arrester to age easily.

[0006] The technical solution adopted by the present invention is as follows:

[0007] An arrester detection method for automatically detecting and loading a current-limiting resistor, including the following specific steps:

[0008] S1. Connect multiple detection units in parallel, and each detection unit is connected to a DC high-voltage measurement and control unit. Each detection unit includes a lightning arrester under test, a microammeter, and an automatic detection and loading current-limiting resistance unit connected in series in sequence.

[0009] S2. The DC high-voltage measurement and control unit outputs a DC high-voltage signal. The DC high-voltage signal passes through the lightning arrester under test, and the microammeter records the current signal of the lightning arrester under test.

[0010] S3. The current signal enters the detection unit to determine whether a current-limiting resistance is loaded in the detection unit: If the rate of change of the current of the lightning arrester under test with time, that is, the current slope of the lightning arrester under test, exceeds the set value, the current-limiting resistance is loaded; otherwise, the current-limiting resistance is not loaded.

[0011] Furthermore, the automatic detection and loading current-limiting resistance unit includes a current slope detection circuit, a relay control circuit, and a relay connected in series in sequence.

[0012] Furthermore, the process of loading the current-limiting resistance in step S3 is as follows: The relay control circuit controls the normally open contact of the relay to connect the current-limiting resistance.

[0013] Furthermore, the process of not loading the current-limiting resistance in step S3 is as follows: The relay control circuit controls the normally closed contact of the relay to connect to the current slope detection circuit.

[0014] The present invention has the following beneficial effects compared with the prior art:

[0015] When detecting, the present invention connects multiple detection units in parallel to realize the simultaneous detection of multiple sections of lightning arresters at one time, greatly improving the detection efficiency of the lightning arrester under test; by setting the automatic detection and loading current-limiting resistance unit to load the current-limiting resistance when the current slope exceeds the set value, the influence caused by the reference voltage difference of multiple sections of lightning arresters under test is eliminated, and it is prevented that too large current appears during the detection process, which makes the lightning arrester easy to age. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The following further describes the present invention in conjunction with the drawings and specific embodiments:

[0017] Figure 1 is a schematic flow chart of a method for detecting a lightning arrester with automatic detection and loading current-limiting resistance according to the present invention;

[0018] Figure 2 is a schematic wiring diagram of parallel detection of multiple sections of lightning arresters according to the present invention;

[0019] Figure 3 is a schematic circuit block diagram of the automatic detection and loading current-limiting resistance unit according to the present invention;

[0020] Figure 4It is a schematic diagram of the current slope detection circuit where the current changes with time in the present invention. Detailed implementation mode Embodiment

[0021] Such as Figure 1 , an arrester detection method for automatically detecting and loading a current-limiting resistor, includes the following steps:

[0022] S1. Connect multiple detection units in parallel, and each detection unit is connected to a DC high-voltage measurement and control unit. Each detection unit includes a arrester under test, a microammeter, and an automatic detection and loading current-limiting resistor unit connected in series in sequence;

[0023] 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;

[0024] 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 arrester under test changes with time, that is, the current slope of the arrester under test, exceeds the set value, then load the current-limiting resistor; otherwise, do not load the current-limiting resistor.

[0025] Specifically, as Figure 2 shown, it represents a schematic diagram of the parallel detection wiring of multiple-section arresters. The DC high-voltage measurement and control unit outputs a DC high-voltage signal for arrester detection; the detection unit includes a arrester under test, a microammeter, and an automatic detection and loading current-limiting resistor unit connected in series in sequence. The detection unit forms a branch for loading the DC high-voltage signal. Several branches are connected in parallel to detect the arresters on each branch, realizing the simultaneous detection of multiple-section 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 arrester under test; point B is the output current signal after passing through the detection unit.

[0026] Figure 3 is a circuit principle block diagram of the automatic detection and loading current-limiting resistor unit. The automatic detection and loading current-limiting resistor unit includes a current slope detection circuit, a relay control circuit, and a relay connected in series in sequence; where Figure 3 Points A and B in Figure 2 are respectively points A and B in

[0027] Figure 4 is a circuit for detecting the rate at which the current changes with time, that is, the current slope. Points A and D in the figure are Figure 3Points A and D, and point C is the master control switch. Working principle: U1 to U3 are operational amplifiers, and U4 is an AND gate; U1 and its peripheral components R1 and R2 function to convert the current change into a voltage change, U2 and its peripheral components R3 and C0 function to convert the current slope into a voltage, and U3 functions as a voltage comparator; the current signal enters from point A. When point C is at a low level, the current slope detection circuit is locked, and it is impossible to judge the current slope detection. Additionally, when D always outputs a low level, Figure 3 the relay in it is in the normally closed state; when point C is at a high level, the current slope detection circuit is opened, and then Figure 4 according to the output level of U3 in it, Figure 3 the relay control circuit controls the relay to contact point a or b, so that the detection unit does not load or loads a current-limiting resistor, realizing that the current of the arrester under test does not increase rapidly during the boosting process of the DC high-voltage measurement and control unit.

[0028] The present invention automatically detects the reference voltage and leakage current of multiple arresters under test at one time by setting multiple detection units and an automatic detection and loading current-limiting resistor unit, greatly improving the arrester detection efficiency; at the same time, eliminating the influence brought by the reference voltage difference of multiple arresters under test and preventing the occurrence of excessive current during the detection process, which is likely to cause the arrester to age.

[0029] The embodiments described above are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the principle and essence of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An arrester detection method for automatically detecting and loading a current-limiting resistor, characterized in that It includes the following steps specifically: S1. Connect multiple detection units in parallel, and each detection unit is connected to a DC high-voltage measurement and control unit. Each detection unit includes a lightning arrester under test, a microammeter, and an automatic detection and loading current-limiting resistance 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 lightning arrester under test, and the microammeter records the current signal of the lightning arrester under test; S3. The current signal enters the detection unit to judge whether a current-limiting resistance is loaded in the detection unit: If the rate of change of the current of the lightning arrester under test, that is, the current slope of the lightning arrester under test, exceeds the set value, then load the current-limiting resistance; otherwise, do not load the current-limiting resistance; Among them, the automatic detection and loading current-limiting resistance unit includes a current slope detection circuit, a relay control circuit, and a relay connected in series in sequence; The process of loading the current-limiting resistance is as follows: The normally open contact of the relay is connected to the current-limiting resistance under the control of the relay control circuit; The process of not loading the current-limiting resistance is as follows: The normally closed contact of the relay is connected to the current slope detection circuit under the control of the relay control circuit; Specifically, the current slope detection circuit is as follows: The resistor R1 is connected to the "-" terminal of U1. The output terminal of U1 is connected to the "-" terminal of U2 through the capacitor C0. The resistor R2 is connected between the "-" terminal and the output terminal of U1. The "+" terminal of U1 is grounded; The output terminal of U2 is connected to the "+" terminal of U3. The resistor R3 is connected between the "-" terminal and the output terminal of U2. The "+" terminal of U2 is grounded; One end of the resistor R5 is connected to the "-" terminal of U3, and the other end is connected to the power supply; One end of the resistor R4 is connected to the "-" terminal of U3, and the other end is grounded. The output terminal of U3 is connected to one input terminal of U4. The other input terminal of U4 is connected to point C. The output terminal of U4 is connected to point D; The current signal enters from point A. When point C is at a low level, the current slope detection circuit is locked, and it is impossible to judge the current slope detection. In addition, when point D always outputs a low level, the relay is in the normally closed state; When point C is at a high level, the current slope detection circuit is opened. According to the output level of U3, the relay control circuit controls the relay to contact point a or point b to realize that the detection unit does not load or loads the current-limiting resistance; Among them, U1~U3 are operational amplifiers, and U4 is an AND gate; Point A is the current signal after passing through the lightning arrester under test; Point B is the output current signal after passing through the detection unit; Point C is the master switch; 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; U1 and its peripheral components, namely the resistors R1 and R2, play the role of converting the current change into a voltage change. U2 and its peripheral components, namely the resistors R3 and the capacitor C0, play the role of converting the current slope into a voltage; U3 functions as a voltage comparator.

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