High-voltage cable line hidden danger discharge on-line monitoring circuit

Abstract

The utility model discloses a high voltage cable line hidden danger discharge on-line monitoring circuit, comprising a protection circuit, a front end amplification circuit, a chopping amplification and filter circuit and a frequency adaptive selection circuit which are connected in sequence, a signal input end of the protection circuit is connected to a terminal joint of a high voltage cable line or a cross interconnection grounding box; the signal output end of the frequency adaptive selection circuit is connected with a processor. The cable hidden danger discharge signal acquisition device is simple in circuit structure, reasonable in design, convenient to realize, capable of effectively realizing acquisition of cable hidden danger discharge signals, favorable for better monitoring the operation state of a cable line and guaranteeing stable operation of an electric power system, good in use effect and convenient to popularize and use.

Description

Technical Field

[0001] The utility model belongs to the technical field of electric power systems, and in particular relates to an online monitoring circuit for hidden danger discharge of a high-voltage cable line. Background Art

[0002] With the rapid advancement of urbanization in my country, the population and key power equipment are becoming increasingly concentrated. Traditional overhead lines are unable to meet the power needs of modern life and production, and are gradually being replaced by cross-linked polyethylene lines with small footprint and stable performance, making them the main force for urban power transmission. Significantly different from overhead lines, when cross-linked polyethylene lines fail, they often show progressive hidden failures that are difficult to capture through manual visual monitoring. Therefore, it is crucial to develop an effective monitoring device for the operating status of high-voltage cable lines.

[0003] Distributed cable line monitoring devices usually have the main task of capturing the traveling wave current during a fault. This type of fault traveling wave current has obvious characteristics, significant amplitude and low frequency, so it is relatively easy to capture. However, for progressive faults in cable lines, it is quite challenging to obtain the early hidden danger discharge signals. The hidden danger discharge signal has a high frequency, decays rapidly, and has a relatively small amplitude, which is difficult to capture effectively by traditional traveling wave current acquisition methods. Therefore, identifying hidden danger discharge information in cable lines has become a major problem. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide an online monitoring circuit for hidden danger discharge of high-voltage cable lines in view of the deficiencies in the above-mentioned prior art. The circuit structure is simple, the design is reasonable, and the implementation is convenient. The circuit can effectively realize the collection of hidden danger discharge signals of cables, which helps to better monitor the operating status of cable lines and ensure the stable operation of power systems. The utility model has good use effect and is easy to promote and use.

[0005] In order to solve the above technical problems, the technical solution adopted by the utility model is: an online monitoring circuit for hidden danger discharge of a high-voltage cable line, comprising a protection circuit, a front-end amplifier circuit, a chopper amplifier and filter circuit and a frequency adaptive selection circuit connected in sequence, the signal input end of the protection circuit is connected to the terminal joint of the high-voltage cable line or the cross-connection grounding box, and the signal output end of the frequency adaptive selection circuit is connected to a processor.

[0006] The above-mentioned online monitoring circuit for hidden danger discharge of a high-voltage cable line, the protection circuit includes a varistor MOV and a thermistor RT, one end of the varistor MOV and one end of the thermistor RT are both connected to the signal input terminal CT, and the other end of the varistor MOV and the other end of the thermistor RT are both grounded.

[0007] The above-mentioned high-voltage cable line hidden danger discharge online monitoring circuit, the front-end amplifier circuit includes a programmable amplifier U1 of model AD8253, a non-polar capacitor C1, a non-polar capacitor C2, a non-polar capacitor C3, a non-polar capacitor C4, a non-polar capacitor C5, a non-polar capacitor C6, a non-polar capacitor C7, a non-polar capacitor C8, a resistor R1, a resistor R2, a resistor R3, a resistor R5, a resistor R6 and a resistor R7, one end of the resistor R1 is connected to one end of the thermistor RT, one end of the non-polar capacitor C1 and one end of the non-polar capacitor C2 are both connected to the other end of the resistor R1, one end of the resistor R2 and one end of the non-polar capacitor C3 are both connected to the other end of the non-polar capacitor C2, the other end of the non-polar capacitor C3 and one end of the resistor R3 are both connected to the programmable amplifier The 10th pin of the program-controlled amplifier U1 is connected, the 1st pin, the 2nd pin, the 3rd pin and the 9th pin of the program-controlled amplifier U1, the other end of the non-polar capacitor C1, the other end of the resistor R2, the other end of the resistor R3, the two ends of the non-polar capacitor C4 and the two ends of the non-polar capacitor C5 are all grounded; the 8th pin of the program-controlled amplifier U1, one end of the non-polar capacitor C6 and one end of the non-polar capacitor C7 are all connected to VDD, the other end of the non-polar capacitor C6 and the other end of the non-polar capacitor C7 are all grounded, the 5th pin of the program-controlled amplifier U1 is grounded through the resistor R5, the 4th pin of the program-controlled amplifier U1 is grounded through the resistor R6, the 7th pin of the program-controlled amplifier U1 is connected to one end of the resistor R7, and the other end of the resistor R7 is grounded through the non-polar capacitor C8.

[0008] The above-mentioned high-voltage cable line hidden danger discharge online monitoring circuit, the chopper amplification and filtering circuit includes an operational amplifier U2 of model ICL7650, a diode D1, a diode D2, a non-polar capacitor C9, a non-polar capacitor C10, a non-polar capacitor C11, a non-polar capacitor C12, a resistor R8, a resistor R9, a resistor R10, a resistor R11 and a resistor R12, one end of the resistor R8, one end of the non-polar capacitor C9 and one end of the resistor R9 are all connected to the other end of the resistor R7, the 5th pin of the operational amplifier U2, the anode of the diode D1, the cathode of the diode D2 and one end of the non-polar capacitor C10 are all connected to the resistor R9 The other end of the resistor R8, the other end of the non-polar capacitor C9 and the other end of the non-polar capacitor C10 are all grounded, the 4th and 9th pins of the operational amplifier U2, the cathode of the diode D1, the anode of the diode D2 and one end of the resistor R12 are all connected to one end of the resistor R11, the other end of the resistor R11 is grounded, the 10th pin of the operational amplifier U2 and one end of the resistor R10 are all connected to the other end of the resistor R12, the 1st pin of the operational amplifier U2 is connected to the 8th pin through the non-polar capacitor C11, and the 2nd pin of the operational amplifier U2 is connected to the 8th pin through the non-polar capacitor C12.

[0009] The above-mentioned high-voltage cable line hidden danger discharge online monitoring circuit, the frequency adaptive selection circuit includes a programmable amplifier U3 of model AD8253, a non-polar capacitor C13, a non-polar capacitor C14, a non-polar capacitor C15, a resistor R13, a resistor R14 and a resistor R15, the first pin of the programmable amplifier U3 is connected to the other end of the resistor R10 through the resistor R13, and is grounded through the non-polar capacitor C13, the 10th pin of the programmable amplifier U3 is connected to the other end of the resistor R10 through the non-polar capacitor C15, and is connected to the 7th pin of the programmable amplifier U3, the 7th pin of the programmable amplifier U3 is connected to one end of the resistor R15, the other end of the resistor R15 is grounded through the non-polar capacitor C14, and is the signal output terminal Vout connected to the processor, the 3rd pin of the programmable amplifier U3 is grounded, and the 2nd pin of the programmable amplifier U3 is grounded through the resistor R14.

[0010] In the above-mentioned online monitoring circuit for hidden danger discharge of high-voltage cable lines, the processor adopts STM32F103C6T6.

[0011] Compared with the prior art, the utility model has the following advantages: the utility model has a simple circuit structure, a reasonable design, and is easy to implement. It can effectively realize the collection of cable hidden danger discharge signals, help to better monitor the operating status of the cable line, and ensure the stable operation of the power system. It has good use effect and is easy to promote and use.

[0012] The technical solution of the utility model is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a circuit schematic diagram of the utility model.

[0014] Description of reference numerals:

[0015] 1—protection circuit; 2—front-end amplifier circuit; 3—chopper amplifier and filter circuit;

[0016] 4—Frequency adaptive selection circuit. DETAILED DESCRIPTION

[0017] like Figure 1 As shown, the utility model of the high-voltage cable line hidden danger discharge online monitoring circuit includes a protection circuit 1, a front-end amplifier circuit 2, a chopper amplifier and filter circuit 3 and a frequency adaptive selection circuit 4 connected in sequence, the signal input end of the protection circuit 1 is connected to the terminal joint of the high-voltage cable line or the cross-connection grounding box, and the signal output end of the frequency adaptive selection circuit 4 is connected to a processor.

[0018] In this embodiment, Figure 1 As shown, the protection circuit 1 includes a varistor MOV and a thermistor RT, one end of the varistor MOV and one end of the thermistor RT are both connected to the signal input terminal CT, and the other end of the varistor MOV and the other end of the thermistor RT are both grounded.

[0019] In specific implementation, the protection circuit is completed by the cooperation of the varistor MOV and the thermistor RT. If there is an overvoltage or overheating situation, the MOV varistor can effectively cut off the power frequency continuous current, and the RT can also be cut off to protect the circuit.

[0020] In this embodiment, Figure 1As shown, the front-end amplifier circuit 2 includes a programmable amplifier U1 of model AD8253, a non-polar capacitor C1, a non-polar capacitor C2, a non-polar capacitor C3, a non-polar capacitor C4, a non-polar capacitor C5, a non-polar capacitor C6, a non-polar capacitor C7, a non-polar capacitor C8, a resistor R1, a resistor R2, a resistor R3, a resistor R5, a resistor R6 and a resistor R7, one end of the resistor R1 is connected to one end of the thermistor RT, one end of the non-polar capacitor C1 and one end of the non-polar capacitor C2 are both connected to the other end of the resistor R1, one end of the resistor R2 and one end of the non-polar capacitor C3 are both connected to the other end of the non-polar capacitor C2, the other end of the non-polar capacitor C3 and one end of the resistor R3 are both connected to the 10th lead of the programmable amplifier U1. The first pin, the second pin, the third pin and the ninth pin of the programmable amplifier U1, the other end of the non-polar capacitor C1, the other end of the resistor R2, the other end of the resistor R3, the two ends of the non-polar capacitor C4 and the two ends of the non-polar capacitor C5 are all grounded; the eighth pin of the programmable amplifier U1, one end of the non-polar capacitor C6 and one end of the non-polar capacitor C7 are all connected to VDD, the other end of the non-polar capacitor C6 and the other end of the non-polar capacitor C7 are all grounded, the fifth pin of the programmable amplifier U1 is grounded through the resistor R5, the fourth pin of the programmable amplifier U1 is grounded through the resistor R6, the seventh pin of the programmable amplifier U1 is connected to one end of the resistor R7, and the other end of the resistor R7 is grounded through the non-polar capacitor C8.

[0021] In this embodiment, Figure 1 As shown, the chopper amplifier and filter circuit 3 includes an operational amplifier U2 of model ICL7650, a diode D1, a diode D2, a non-polar capacitor C9, a non-polar capacitor C10, a non-polar capacitor C11, a non-polar capacitor C12, a resistor R8, a resistor R9, a resistor R10, a resistor R11 and a resistor R12, one end of the resistor R8, one end of the non-polar capacitor C9 and one end of the resistor R9 are all connected to the other end of the resistor R7, the 5th pin of the operational amplifier U2, the anode of the diode D1, the cathode of the diode D2 and one end of the non-polar capacitor C10 are all connected to the other end of the resistor R9, and the The other end of the resistor R8, the other end of the non-polar capacitor C9 and the other end of the non-polar capacitor C10 are all grounded, the 4th and 9th pins of the operational amplifier U2, the cathode of the diode D1, the anode of the diode D2 and one end of the resistor R12 are all connected to one end of the resistor R11, the other end of the resistor R11 is grounded, the 10th pin of the operational amplifier U2 and one end of the resistor R10 are all connected to the other end of the resistor R12, the 1st pin of the operational amplifier U2 is connected to the 8th pin through the non-polar capacitor C11, and the 2nd pin of the operational amplifier U2 is connected to the 8th pin through the non-polar capacitor C12.

[0022] In specific implementation, the front-end amplifier circuit 2 cooperates with the chopper amplifier circuit to achieve chopping and amplification of the weak cable hidden danger discharge traveling wave signal by adjusting the size of the resistor; a noise filter circuit is added to the filter circuit to eliminate the white noise signal in the filter signal and the interference signal outside the filter bandwidth, thereby improving the signal stability.

[0023] In this embodiment, Figure 1 As shown, the frequency adaptive selection circuit 4 includes a programmable amplifier U3 of model AD8253, a non-polar capacitor C13, a non-polar capacitor C14, a non-polar capacitor C15, a resistor R13, a resistor R14 and a resistor R15. The first pin of the programmable amplifier U3 is connected to the other end of the resistor R10 through the resistor R13 and is grounded through the non-polar capacitor C13. The 10th pin of the programmable amplifier U3 is connected to the other end of the resistor R10 through the non-polar capacitor C15 and is connected to the 7th pin of the programmable amplifier U3. The 7th pin of the programmable amplifier U3 is connected to one end of the resistor R15, and the other end of the resistor R15 is grounded through the non-polar capacitor C14 and is a signal output terminal Vout connected to the processor. The 3rd pin of the programmable amplifier U3 is grounded, and the 2nd pin of the programmable amplifier U3 is grounded through the resistor R14.

[0024] In this embodiment, the processor adopts STM32F103C6T6.

[0025] In the specific implementation, the actual cable hidden danger discharge frequency (20kHz-30kHz) is subdivided according to the scene, and the weak discharge signal is extracted by combining the adaptive selection circuit 4 with the STM32F103C6T6.

[0026] When the utility model is used, the signal input terminal CT is connected to the terminal joint of the high-voltage cable line or the cross-connected grounding box, the front-end amplifier circuit 2 and the chopper amplifier and filter circuit 3 are used to chop and amplify the weak cable hidden danger discharge traveling wave signal and filter the interference signal, and then the cable hidden danger discharge frequency is subdivided by the adaptive selection circuit 4 and the processor to realize the extraction of the weak discharge signal. When a fault occurs in the cable line, the high-frequency transient signal transmitted along the core wire or the sheath grounding wire of the cable line can be used to monitor the state of the cable line in real time, so as to accurately locate the fault point and provide powerful troubleshooting support for the operation and maintenance personnel.

[0027] The above is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Any simple modification, change and equivalent structural change made to the above embodiments according to the technical essence of the present invention shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. An online monitoring circuit for hidden danger discharge of high-voltage cable lines, characterized in that: The invention comprises a protection circuit (1), a front-end amplifier circuit (2), a chopping amplifier and filter circuit (3) and a frequency adaptive selection circuit (4) which are connected in sequence, wherein the signal input end of the protection circuit (1) is connected to a terminal joint of a high-voltage cable line or a cross-connection grounding box, and the signal output end of the frequency adaptive selection circuit (4) is connected to a processor.

2. According to the online monitoring circuit for hidden danger discharge of high-voltage cable lines as claimed in claim 1, it is characterized in that: The protection circuit (1) comprises a varistor MOV and a thermistor RT, one end of the varistor MOV and one end of the thermistor RT are both connected to the signal input terminal CT, and the other end of the varistor MOV and the other end of the thermistor RT are both grounded.

3. According to the online monitoring circuit for hidden danger discharge of high-voltage cable lines as claimed in claim 2, it is characterized in that: The front-end amplifier circuit (2) comprises a programmable amplifier U1 of model AD8253, a non-polar capacitor C1, a non-polar capacitor C2, a non-polar capacitor C3, a non-polar capacitor C4, a non-polar capacitor C5, a non-polar capacitor C6, a non-polar capacitor C7, a non-polar capacitor C8, a resistor R1, a resistor R2, a resistor R3, a resistor R5, a resistor R6 and a resistor R7, one end of the resistor R1 is connected to one end of the thermistor RT, one end of the non-polar capacitor C1 and one end of the non-polar capacitor C2 are both connected to the other end of the resistor R1, one end of the resistor R2 and one end of the non-polar capacitor C3 are both connected to the other end of the non-polar capacitor C2, and the other end of the non-polar capacitor C3 and one end of the resistor R3 are both connected to the tenth pin of the programmable amplifier U1. The first pin, the second pin, the third pin and the ninth pin of the programmable amplifier U1, the other end of the non-polar capacitor C1, the other end of the resistor R2, the other end of the resistor R3, the two ends of the non-polar capacitor C4 and the two ends of the non-polar capacitor C5 are all grounded; the eighth pin of the programmable amplifier U1, one end of the non-polar capacitor C6 and one end of the non-polar capacitor C7 are all connected to VDD, the other end of the non-polar capacitor C6 and the other end of the non-polar capacitor C7 are all grounded, the fifth pin of the programmable amplifier U1 is grounded through the resistor R5, the fourth pin of the programmable amplifier U1 is grounded through the resistor R6, the seventh pin of the programmable amplifier U1 is connected to one end of the resistor R7, and the other end of the resistor R7 is grounded through the non-polar capacitor C8.

4. A high-voltage cable line hidden danger discharge online monitoring circuit according to claim 3, characterized in that: The chopper amplifier and filter circuit (3) comprises an operational amplifier U2 of model ICL7650, a diode D1, a diode D2, a non-polar capacitor C9, a non-polar capacitor C10, a non-polar capacitor C11, a non-polar capacitor C12, a resistor R8, a resistor R9, a resistor R10, a resistor R11 and a resistor R12, one end of the resistor R8, one end of the non-polar capacitor C9 and one end of the resistor R9 are all connected to the other end of the resistor R7, the fifth pin of the operational amplifier U2, the anode of the diode D1, the cathode of the diode D2 and one end of the non-polar capacitor C10 are all connected to the other end of the resistor R9, and the The other end of the resistor R8, the other end of the non-polar capacitor C9 and the other end of the non-polar capacitor C10 are all grounded, the 4th pin and the 9th pin of the operational amplifier U2, the cathode of the diode D1, the anode of the diode D2 and one end of the resistor R12 are all connected to one end of the resistor R11, the other end of the resistor R11 is grounded, the 10th pin of the operational amplifier U2 and one end of the resistor R10 are all connected to the other end of the resistor R12, the 1st pin of the operational amplifier U2 is connected to the 8th pin through the non-polar capacitor C11, and the 2nd pin of the operational amplifier U2 is connected to the 8th pin through the non-polar capacitor C12.

5. A high-voltage cable line hidden danger discharge online monitoring circuit according to claim 4, characterized in that: The frequency adaptive selection circuit (4) comprises a programmable amplifier U3 of model AD8253, a non-polar capacitor C13, a non-polar capacitor C14, a non-polar capacitor C15, a resistor R13, a resistor R14 and a resistor R15, wherein the first pin of the programmable amplifier U3 is connected to the other end of the resistor R10 through the resistor R13 and is grounded through the non-polar capacitor C13, the tenth pin of the programmable amplifier U3 is connected to the other end of the resistor R10 through the non-polar capacitor C15 and is connected to the seventh pin of the programmable amplifier U3, the seventh pin of the programmable amplifier U3 is connected to one end of the resistor R15, the other end of the resistor R15 is grounded through the non-polar capacitor C14 and is a signal output terminal Vout connected to the processor, the third pin of the programmable amplifier U3 is grounded, and the second pin of the programmable amplifier U3 is grounded through the resistor R14.

6. A high-voltage cable line hidden danger discharge online monitoring circuit according to claim 5, characterized in that: The processor used is STM32F103C6T6.

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