A lightning arrester live detection device and detection method

Abstract

The present invention provides a lightning arrester live detection device and detection method, which mainly solves the problem that the leakage current of the existing input monitoring host is the leakage current after being transformed by the current transformer installed at the grounding end of the lightning arrester, and cannot be used by an external live detection instrument, thus affecting the live detection test. It includes a monitoring host, a signal acquisition module connected to the grounding end of the monitored lightning arrester, a front module connected to the input end of the monitoring host, and a live detection instrument connected to the front module. Through the scheme of the present invention, during monitoring, the leakage current can be collected by the signal acquisition module, and then coupled to the monitoring host for detection through the transformation of the front module; when performing live detection of the operating parameters of the lightning arrester, the leakage current can be diverted to the live detection device before being transformed by the front module, which is convenient and quick. Only one live detection instrument is needed to detect multiple lightning arresters, which can effectively reduce costs.

Description

Technical Field

[0001] The invention relates to a live detection device and a detection method, and in particular to a live detection device and a detection method for a lightning arrester. Background Art

[0002] When monitoring a lightning arrester, resistive current is a key parameter that directly reflects the operating status of the arrester. However, the circuit of the device for online monitoring of resistive current is complex, and it is costly to configure an online monitoring device for measuring resistive current for each lightning arrester.

[0003] Monitoring device for lightning arrester in switch cabinet of power transmission and transformation system, such as Figure 1 As shown, it is generally composed of two parts: a current transformer TA and a monitoring host 1. The current transformer TA is installed at the grounding end of the lightning arrester in the high-voltage room, and the monitoring host 1 is installed on the door panel of the secondary room of the switch cabinet. The current transformer TA and the monitoring host 1 are electrically connected by a signal line 4.

[0004] When conducting a live detection test, it is necessary to directly collect the leakage current of the lightning arrester for testing. However, in the existing monitoring device, the leakage current input to the monitoring host is the leakage current converted by the current transformer installed at the grounding terminal of the lightning arrester, which cannot be used by an external live detection instrument, thus affecting the conduct of the live detection test. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problem that the leakage current input into the monitoring host of the monitoring device existing in the prior art is the leakage current converted by the current transformer installed at the grounding terminal of the lightning arrester, which cannot be used by the external live detection instrument, thus affecting the live detection test, and to provide a lightning arrester live detection device and detection method.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] A lightning arrester live detection device includes a monitoring host, and is special in that it also includes a signal acquisition module connected to the grounding end of the monitored lightning arrester, a front module connected to the input end of the monitoring host, and a live detection instrument connected to the front module;

[0008] The live detection instrument comprises a live detection circuit JC and a sampling resistor R3 connected in parallel with the live detection circuit JC, wherein the sampling resistor R3 is used to connect to the front module during live detection;

[0009] The front module includes a live detection terminal J1, a live detection terminal J2, a damping resistor R1, a current transformer TB, an electric control switch, a detection control circuit and a current transformer TA;

[0010] The input coil of the current transformer TB includes a first coil and a second coil connected in sequence, the first coil and the second coil have the same number of turns and opposite winding directions, and the live detection terminal J1 is connected to the connection point of the first coil and the second coil;

[0011] The other end of the second coil is connected to one end of the electric control switch through the damping resistor R1, the other end of the electric control switch is connected to an input end of the current transformer TA, the other input end of the current transformer TA is connected to the live detection terminal J2, the two output ends of the current transformer TB are respectively connected to the two input ends of the detection control circuit, the two output ends of the detection control circuit are respectively connected to the control end of the electric control switch, and the two output ends of the current transformer TA are respectively connected to the two input ends of the monitoring host, so that when the output current of the current transformer TB is not 0, the electric control switch is in a disconnected state;

[0012] The live detection terminal J1 and the live detection terminal J2 are respectively connected to the two ends of the sampling resistor R3 during live detection;

[0013] The other end of the first coil is connected to an output end of a signal acquisition module, and the other output end of the signal acquisition module is connected to a live detection terminal J2.

[0014] Furthermore, the signal acquisition module includes a nonlinear resistor RV1, a protection resistor R2 and a bidirectional breakdown diode TVS1;

[0015] The nonlinear resistor RV1 is connected in series to the grounding end of the monitored lightning arrester, one end of the protection resistor R2 is connected to one end of the nonlinear resistor RV1, the other end of the protection resistor R2 is connected to one end of the bidirectional breakdown diode TVS1, and is also connected to the other end of the first coil, the other end of the bidirectional breakdown diode TVS1 is connected to the other end of the nonlinear resistor RV1, and is also connected to the live detection terminal J2.

[0016] Furthermore, two ends of the bidirectional breakdown diode TVS1 are respectively connected to the other end of the first coil and the power detection terminal J2 through signal lines.

[0017] Furthermore, the electronically controlled switch is a relay KP.

[0018] At the same time, the present invention also provides a method for detecting a lightning arrester that is charged, which is based on the above detection device and is special in that it includes the following steps:

[0019] 1) When monitoring the leakage current of the arrester, the leakage current flows through the current transformer TB, the damping resistor R1, the electronically controlled switch and the current transformer TA. At this time, since the output current of the current transformer TB is 0, the detection control circuit detects that the output current is 0, controls the electronically controlled switch to remain closed, and couples the leakage current to the monitoring host to monitor the leakage current;

[0020] 2) When the operating parameters of the arrester are tested live, the two input terminals of the live detection instrument are connected to the live detection terminals J1 and J2, and a part of the leakage current flows through the sampling resistor R3. At this time, the output current of the current transformer TB is not 0. The detection control circuit detects that the output current is not 0, and controls the electric control switch to be disconnected, so that all the leakage current flows through the sampling resistor R3, and the live detection is completed through the live detection circuit JC;

[0021] 3) After the live detection is completed, when the connection between the live detection instrument and the live detection terminals J1 and J2 is disconnected, the output current of the current transformer TB becomes 0, the detection control circuit detects that the output current is 0, controls the electronic control switch to close, couples the leakage current to the monitoring host, and re-monitors the leakage current of the arrester.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The leakage current is collected through the signal acquisition module. The leakage current flows through the current transformer TB, the damping resistor R1, the electric control switch and the current transformer TA. The leakage current is coupled to the monitoring host to complete the leakage current monitoring. When the live detection test is required, the live detection instrument is connected through the live detection terminals J1 and J2. At this time, part of the leakage current enters the live detection instrument, so that the output current of the current transformer TB is not 0. The electric control switch is disconnected through the detection control circuit, and all the leakage current is introduced into the live detection instrument. The live detection test can be directly carried out, which is convenient and fast. In addition, only one live detection instrument is needed for the whole station to detect the resistive current of the arrester of the whole station, which can effectively reduce the cost.

[0024] 2. The live detection instrument in the present invention does not require the input resistance to be 0, and adopts sampling resistance for sampling, which belongs to direct sampling and has better measurement accuracy. Compared with the existing live detection scheme, the input resistance of the live detector is required to be 0 so that the leakage current can be introduced into the live detector, and the signal sampling is generally carried out by using a zero-flux current transformer which is expensive and has high process requirements. The live detector in the present invention is low-cost and has low process requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is the circuit schematic diagram of the existing monitoring device;

[0026] Figure 2 The present invention is a circuit diagram of an embodiment of a lightning arrester live detection device and a detection method.

[0027] In the figure, 1- monitoring host, 2- signal acquisition module, 3- front module, 4- signal line, 5- detection control circuit, 6- live detection instrument. DETAILED DESCRIPTION

[0028] In order to make the purpose, advantages and features of the present invention clearer, the following is a further detailed description of a lightning arrester live detection device and detection method proposed by the present invention in combination with the accompanying drawings and specific embodiments. According to the following specific implementation methods, the advantages and features of the present invention will be clearer. It should be noted that: the drawings are all in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention; secondly, the structure shown in the drawings is often part of the actual structure.

[0029] In the description of the present invention, it should be noted that the terms “first” and “second” are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0030] like Figure 2 As shown, a lightning arrester live detection device of the present invention includes a monitoring host 1, a signal acquisition module 2 connected to the grounding end of the monitored lightning arrester, a front module 3 connected to the input end of the monitoring host 1, and a live detection instrument 6 connected to the front module 3.

[0031] The front module 3 includes a live detection terminal J1, a live detection terminal J2, a damping resistor R1, a current transformer TB, an electric control switch, a detection control circuit 5 and a current transformer TA; wherein the electric control switch is a relay KP, and of course, it can also be other electric control switches that can be electrically controlled in the prior art; the detection control circuit 5 adopts the prior art, when it is detected that the output current of the current transformer TB is 0, the relay KP is not controlled to act, and when it is detected that the output current of the current transformer TB is not 0, the relay KP is controlled to act, so that the relay KP The line where the contact interface is located is in an open circuit state, and the input coil of the current transformer TB includes a first coil and a second coil connected in sequence. The first coil and the second coil have the same number of turns and opposite winding directions. When the leakage current flows through the first coil and the second coil in sequence, the current flowing through the first coil and the second coil is equal, and the magnetic fields generated by the first coil and the second coil will cancel each other out. Therefore, the output current of the current transformer TB is 0; the live detection terminal J1 is connected to the connection point of the first coil and the second coil, and one input end of the current transformer TB is connected to the first contact of the relay KP through the damping resistor R1, and the second contact of the relay KP is connected to an input end of the current transformer TA, and the other input end of the current transformer TA is connected to the live detection terminal J2. When the live detection terminal J1 and the live detection terminal J2 are connected to the live detection instrument 6, a part of the leakage current will be diverted to the live detection instrument 6. At this time, the currents flowing through the first coil and the second coil are not equal, resulting in that the magnetic fields generated by the first coil and the second coil cannot be canceled out, and the output current will be induced on the output coil, and then the relay KP is controlled by the detection control circuit 5. Disconnect, and guide all the leakage current into the live detection instrument 6, the two ends of the output coil of the current transformer TB are respectively connected to the two input ends of the detection control circuit 5, the two output ends of the detection control circuit 5 are respectively connected to the two coil interfaces of the relay KP, and the two output ends of the current transformer TA are respectively connected to the two input ends of the monitoring host 1; the live detection instrument 6 includes a live detection circuit JC and a sampling resistor R3 connected in parallel with the live detection circuit JC. When performing live detection, the live detection terminal J1 and the live detection terminal J2 are respectively connected to the two ends of the sampling resistor.

[0032] The signal acquisition module 2 includes a nonlinear resistor RV1, a protective resistor R2 and a bidirectional breakdown diode TVS1; the nonlinear resistor RV1 is connected in series to the grounding terminal of the monitored lightning arrester, one end of the protective resistor R2 is connected to one end of the nonlinear resistor RV1, the other end of the protective resistor R2 is connected to one end of the bidirectional breakdown diode TVS1, and is connected to the other end of the first coil through a signal line 4, the other end of the bidirectional breakdown diode TVS1 is connected to the other end of the nonlinear resistor RV1, and is connected to the live detection terminal J2 through the signal line 4.

[0033] A method for detecting a lightning arrester being charged comprises the following steps:

[0034] 1) When monitoring the leakage current of the arrester, the leakage current flows through the current transformer TB, the damping resistor R1, the electric control switch and the current transformer TA. At this time, since the output current of the current transformer TB is 0, the detection control circuit 5 detects that the output current is 0, controls the electric control switch to remain closed, and couples the leakage current to the monitoring host 1 to monitor the leakage current;

[0035] 2) When the operating parameters of the arrester (e.g., total current, resistive current, system voltage, harmonic voltage, etc.) are tested live, the two input terminals of the live detection instrument 6 are connected to the live detection terminals J1 and J2, and a part of the leakage current flows through the sampling resistor R3. At this time, the output current of the current transformer TB is not 0, and the detection control circuit 5 detects that the output current is not 0, and controls the electric control switch to be disconnected, so that all the leakage current flows through the sampling resistor R3, and the live detection is completed through the live detection circuit JC;

[0036] 3) After the live detection is completed, when the connection between the live detection instrument 6 and the live detection terminals J1 and J2 is disconnected, the output current of the current transformer TB becomes 0, and the detection control circuit 5 detects that the output current is 0, controls the electric control switch to close, couples the leakage current to the monitoring host 1, and re-monitors the leakage current of the lightning arrester.

Claims

1. A lightning arrester live detection device, comprising a monitoring host (1), characterized in that: It also includes a signal acquisition module (2) connected to the grounding end of the monitored lightning arrester, a front module (3) connected to the input end of the monitoring host (1), and a live detection instrument (6) connected to the front module (3); The live detection instrument (6) comprises a live detection circuit JC and a sampling resistor R3 connected in parallel with the live detection circuit JC, wherein the sampling resistor R3 is used to connect to the front module (3) during live detection; The front module (3) comprises a live detection terminal J1, a live detection terminal J2, a damping resistor R1, a current transformer TB, an electric control switch, a detection control circuit (5) and a current transformer TA; The input coil of the current transformer TB includes a first coil and a second coil connected in sequence, the first coil and the second coil have the same number of turns and opposite winding directions, and the live detection terminal J1 is connected to the connection point of the first coil and the second coil; The other end of the second coil is connected to one end of the electric control switch via a damping resistor R1, the other end of the electric control switch is connected to an input end of a current transformer TA, the other input end of the current transformer TA is connected to a live detection terminal J2, the two output ends of the current transformer TB are respectively connected to the two input ends of a detection control circuit (5), the two output ends of the detection control circuit (5) are respectively connected to the control end of the electric control switch, and the two output ends of the current transformer TA are respectively connected to the two input ends of a monitoring host (1), so that when the output current of the current transformer TB is not 0, the electric control switch is in an off state; When the output current of the current transformer TB is 0, the electric control switch is in a closed state; The live detection terminal J1 and the live detection terminal J2 are respectively connected to the two ends of the sampling resistor R3 during live detection; The other end of the first coil is connected to an output end of the signal acquisition module (2), and the other output end of the signal acquisition module (2) is connected to the live detection terminal J2.

2. A lightning arrester live detection device according to claim 1, characterized in that: The signal acquisition module (2) comprises a nonlinear resistor RV1, a protective resistor R2 and a bidirectional breakdown diode TVS1; The nonlinear resistor RV1 is connected in series to the grounding end of the monitored lightning arrester, one end of the protection resistor R2 is connected to one end of the nonlinear resistor RV1, the other end of the protection resistor R2 is connected to one end of the bidirectional breakdown diode TVS1, and is also connected to the other end of the first coil, the other end of the bidirectional breakdown diode TVS1 is connected to the other end of the nonlinear resistor RV1, and is also connected to the live detection terminal J2.

3. A lightning arrester live detection device according to claim 2, characterized in that: The two ends of the bidirectional breakdown diode TVS1 are respectively connected to the other end of the first coil and the live detection terminal J2 through a signal line (4).

4. A lightning arrester live detection device according to claim 3, characterized in that: The electronically controlled switch is a relay KP.

5. A lightning arrester charged detection method, based on a lightning arrester charged detection device according to any one of claims 1 to 4, characterized in that: 1) When monitoring the leakage current of the arrester, the leakage current flows through the current transformer TB, the damping resistor R1, the electric control switch and the current transformer TA. At this time, since the output current of the current transformer TB is 0, the detection control circuit (5) detects that the output current is 0, controls the electric control switch to remain closed, and couples the leakage current to the monitoring host (1) to monitor the leakage current; 2) When the operating parameters of the arrester are tested live, the two input terminals of the live detection instrument (6) are connected to the live detection terminals J1 and J2, and a part of the leakage current flows through the sampling resistor R3. At this time, the output current of the current transformer TB is not zero. The detection control circuit (5) detects that the output current is not zero, and controls the electric control switch to be disconnected, so that all the leakage current flows through the sampling resistor R3, and the live detection is completed through the live detection circuit JC; 3) After the live detection is completed, when the live detection instrument (6) is disconnected from the live detection terminals J1 and J2, the output current of the current transformer TB becomes 0, and the detection control circuit (5) detects that the output current is 0, controls the electric control switch to close, couples the leakage current to the monitoring host (1), and re-monitors the leakage current of the arrester.

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