Integrally-controlled power cable partial discharge simulation method and device

Abstract

The invention discloses an integrated control power cable partial discharge simulation method and device. High voltage is applied to a detection position of a power cable to be detected, partial discharge is simulated at the detection position through a partial discharge model, the type and size of the simulated partial discharge are integrally controlled through an external PC terminal, and a partial discharge detector receives a partial discharge signal. If the terminal joint of the simulated cable is partially discharged, taking the terminal joint of the cable to be detected as a detection position; if the partial discharge of the intermediate joint of the simulated cable is simulated, the connection and conduction part of the two cables is used as a detection part. And the PC end controls the on-off of the numerical control voltage-regulating power supply and controls the voltage boosting and reducing amplitude of the transformer through the numerical control voltage-regulating power supply. The partial discharge model adopts one or more of a point discharge model, a suspension discharge model, an air gap discharge model and a creeping discharge model. According to the invention, simulation of various discharge types is realized, the workload and manual operation errors are reduced, and the convenience and accuracy of power cable discharge simulation are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric power equipment, and in particular relates to a method and device for simulating partial discharge of a power cable with integrated control. Background Art

[0002] During the operation and maintenance of power cables, cable partial discharge detection is not only a critical measure but also an effective method for uncovering potential defects and hidden dangers. Given the diversity and complexity of partial discharge (PD) types, realistic and dynamic simulation of power cable PD facilitates experimental research and training, improving the accuracy and effectiveness of PD identification.

[0003] Existing methods for simulating partial discharge in power cables primarily exploit existing defects in returned power cables or artificially create insulation defects (such as air gaps and scratches). This method is costly, time-consuming, and cannot simulate discharges at cable terminals and intermediate joints individually. Discharge control, voltage control, and partial discharge detection in these existing fault simulation methods are all performed manually. Discharge type, magnitude, and generation and disappearance cannot be precisely controlled, and the simulated discharge types are limited. Existing discharge simulation methods are cumbersome, labor-intensive, lack robust linkage, lack precise control, and produce inaccurate data, significantly impacting the convenience and accuracy of power cable partial discharge simulation. Summary of the Invention

[0004] An object of the present invention is to address the deficiencies of the prior art and provide a method for simulating partial discharge of power cables with integrated control.

[0005] The method of the present invention applies high voltage to the detection point of the power cable to be tested, simulates partial discharge at the detection point through a partial discharge model, controls the type and size of the simulated partial discharge through an external PC end integration, and a partial discharge detector receives the partial discharge signal and sends it to the PC end.

[0006] The detection location is the terminal joint or intermediate joint of the cable to be tested; if partial discharge at the cable terminal joint is simulated, high voltage is applied to the end of one cable, and partial discharge is simulated at the cable end through a partial discharge model, and the shielding layer and armor layer of the cable are grounded; if partial discharge at the cable intermediate joint is simulated, one end of the two cables are connected and conducted, high voltage is applied at the connection point, and partial discharge is simulated at the connection point through a partial discharge model, and the shielding layer and armor layer of both cables are grounded.

[0007] The application of high voltage is achieved through a digitally controlled voltage-regulating power supply and a transformer. The PC controls the switch of the digitally controlled voltage-regulating power supply and controls the voltage step-up and step-down amplitude of the transformer through the digitally controlled voltage-regulating power supply.

[0008] The partial discharge model is one or more of a tip discharge model, a suspension discharge model, an air gap discharge model, and a surface discharge model. The PC end controls the linear motion of the partial discharge model. When the head of the partial discharge model touches the detection point, partial discharge is generated.

[0009] Another object of the present invention is to provide a power cable partial discharge simulation device for implementing the method.

[0010] The device of the invention comprises a simulated partial discharge tube, a control cabinet and a partial discharge model component; the simulated partial discharge tube is arranged above the control cabinet, and the partial discharge model component is arranged on the simulated partial discharge tube.

[0011] The simulated partial discharge cylinder comprises three coaxially arranged parts: a left cylinder, a middle cylinder and a right cylinder; the left cylinder and the right cylinder are both closed at one end by an end cover, and the other end is connected to the middle cylinder; the two end covers are respectively provided with cable connectors, and the left cylinder and the right cylinder are respectively provided with conductive rods, the two conductive rods are located in the same straight line, one end of the two conductive rods is respectively connected to the corresponding cable connector, and the other end is arranged opposite to each other in the middle cylinder; a conductive disk is provided in the middle cylinder, and a conductive column is fixedly provided on the conductive disk, the conductive column is arranged perpendicular to the conductive rod, and the ends of the two conductive rods are both connected to the conductive column.

[0012] The control cabinet is provided with a digitally controlled voltage-regulating power supply, a transformer, an electrode controller, a coupling capacitor, a detection impedance and a partial discharge detector; the digitally controlled voltage-regulating power supply is connected to the low-voltage side input end of the transformer, and the digitally controlled voltage-regulating power supply is controlled by an external PC end; one end of the coupling capacitor is connected to the high-voltage side output end of the transformer, and the other end of the coupling capacitor is connected to the partial discharge detector through the detection impedance, the partial discharge detector detects the discharge type and discharge size data in real time, and the partial discharge detector is connected to the external PC end; the electrode controller is connected to the PC end, and the PC end sends a control signal to the electrode controller to control the partial discharge model component; the high-voltage side output end of the transformer is connected to the conductive column through a cable.

[0013] The partial discharge model assembly includes multiple partial discharge models arranged in parallel. The multiple partial discharge models are controlled to extend and retract by respective stepping motors. The multiple partial discharge models are arranged corresponding to the conductive disks, and the movement direction is perpendicular to the plane of the conductive disks. When the head of the partial discharge model touches the conductive disk, partial discharge is generated.

[0014] The present invention integrates the control of the rise and fall of the test voltage, the start and stop, switching of the fault discharge model, and partial discharge detection, so that the discharge size, discharge type, generation and disappearance of the discharge in the power cable partial discharge simulation process can be controlled, and multiple discharge type simulations can be realized. It also reduces the workload, reduces human errors, and improves the convenience and accuracy of power cable discharge simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The overall structure of the device of the present invention and the internal schematic diagram of the discharge tube; Figure 2 The overall structure of the device of the present invention and the internal schematic diagram of the control cabinet; Figure 3 The overall structure of the device of the present invention and the internal schematic diagram of the partial discharge model component; Figure 4 It is a schematic diagram of the discharge model control device; Figure 5 Schematic diagram of the tip discharge model structure in the present invention; Figure 6 Schematic diagram of the structure of the suspension discharge model in the present invention; Figure 7 Schematic diagram of the air gap discharge model structure in the present invention; Figure 8 Schematic diagram of the structure of the surface discharge model in the present invention. DETAILED DESCRIPTION

[0016] An integrated control method for simulating partial discharge of power cables is disclosed. The method applies high voltage to a detection point of the power cable to be tested, simulates partial discharge at the detection point through a partial discharge model, and integrates control of the type and size of the simulated partial discharge through an external PC end. The partial discharge detector receives the partial discharge signal and sends it to the PC end.

[0017] The test location is the terminal or intermediate joint of the cable under test. To simulate partial discharge at a cable terminal joint, high voltage is applied to the end of one cable, and partial discharge is simulated at the cable end using a partial discharge model. The cable shield and armor are grounded. To simulate partial discharge at an intermediate joint, one end of two cables is connected, high voltage is applied to the connection, and partial discharge is simulated at the connection using a partial discharge model. The shield and armor of both cables are grounded.

[0018] The application of high voltage is achieved through a digitally controlled voltage-regulating power supply and a transformer. The PC controls the switch of the digitally controlled voltage-regulating power supply and controls the voltage step-up and step-down amplitude of the transformer through the digitally controlled voltage-regulating power supply.

[0019] The local discharge model is one or more of a tip discharge model, a suspension discharge model, an air gap discharge model, and a surface discharge model. The PC end controls the linear motion of the local discharge model. When the head of the local discharge model touches the detection point, discharge is generated.

[0020] like Figure 1 、 2As shown in FIG3 , the device for implementing the above method includes a simulated partial discharge tube 1, a control cabinet 2, and a partial discharge model assembly 3. The simulated partial discharge tube 1 is arranged above the control cabinet 2, and the partial discharge model assembly 3 is arranged on the simulated partial discharge tube 1.

[0021] like Figure 1 The simulated partial discharge tube 1 includes three coaxially arranged parts, namely the left cylinder 11, the middle cylinder 12 and the right cylinder 13. The left cylinder 11 and the right cylinder 13 are both closed at one end by an end cover 14, and the other end is connected to the middle cylinder 12. Cable connectors 15 are respectively provided on the two end covers 14, and conductive rods 16 are respectively provided in the left cylinder 11 and the right cylinder 13. The two conductive rods 16 are located on the same straight line. One end of the two conductive rods 16 is connected to the corresponding cable connector 15, and the other end is arranged opposite to each other in the middle cylinder 12. A support frame 17 is provided in the simulated partial discharge tube 1, and the two conductive rods 16 are fixed in the simulated partial discharge tube 1 through the support frame 17. A conductive disk 18 is provided in the middle cylinder 12, and a conductive column 19 is fixed on the conductive disk 18. The conductive column 19 is arranged perpendicular to the conductive rod 16, and the ends of the two conductive rods 16 are connected to the conductive column 19.

[0022] like Figure 2 The control cabinet 2 includes a cabinet body 21, which houses a digitally controlled voltage-regulating power supply 22, a transformer 23, an electrode controller 24, a coupling capacitor 25, a detection impedance 26, and a partial discharge detector 27. The digitally controlled voltage-regulating power supply 22 is connected to the low-voltage input of the transformer 23 and is controlled by an external PC (not shown). One end of the coupling capacitor 25 is connected to the high-voltage output of the transformer 23, and the other end of the coupling capacitor 25 is connected to the partial discharge detector 27 via a detection impedance 26. The partial discharge detector 27 detects discharge type and magnitude in real time and is connected to the external PC. The electrode controller 24 is connected to the PC, which sends control signals to the electrode controller 24 to control the partial discharge model component 3. The high-voltage output of the transformer 23 is connected to the conductive column 19 via a cable, thereby applying pressure to the conductive rod.

[0023] like Figure 3The partial discharge model assembly 3 includes a model tube 31, which is fixedly mounted on the middle cylinder 12 and forms a three-way connection with the middle cylinder 12. A model bracket 32 is disposed within the model tube 31, and multiple partial discharge models 33 are disposed in parallel on the model bracket 32. Each partial discharge model 33 is fixed to the model bracket 32 via a corresponding stepper motor 34, and the model bracket 32 is fixed within the model tube 31. The multiple partial discharge models are one or more of a tip discharge model, a suspended discharge model, an air gap discharge model, and a surface discharge model. The stepper motor 34 is connected to the electrode controller 24. The PC controls each stepper motor 34 through the electrode controller 24, thereby controlling the expansion and contraction of each partial discharge model 33.

[0024] like Figure 4 The lead screw 35 of the stepper motor 34 is threadedly connected to a slider 36, which is movably connected to a guide rod 37. The slider 36 can slide up and down along the guide rod 37. The slider 36 is connected to the partial discharge model 33 via a connecting rod 38, controlling the linear motion of the partial discharge model 33. The head of the partial discharge model 33 is positioned corresponding to the conductive disk 18, and the direction of motion of the partial discharge model 33 is perpendicular to the plane of the conductive disk 18.

[0025] The PC host computer is internally installed with centralized control software. The PC is connected to the CNC voltage-regulating power supply signal, controlling its on / off state and, through it, the transformer's step-up and step-down voltages. The PC is also connected to the electrode controller signal, which controls the movement of the partial discharge model. The PC is also connected to the partial discharge detector signal, processing the partial discharge signals received by the detector. The PC host computer issues control commands to the CNC voltage-regulating power supply and electrode controller, which then feed back execution data to the PC host computer. The electrode controller controls the rotation direction of the stepper motors connected to each partial discharge model, controlling the on / off switching of each partial discharge model.

[0026] The specific structures of the four discharge models are as follows: like Figure 5As shown, the tip discharge model includes a fixedly connected front tube 411 and rear tube 412. The front and rear tubes 411, 412 are made of insulating material, forming a discharge chamber. A metal needle 413 is disposed within the discharge chamber. A protrusion is provided on the end surface of the front tube 411, through which a first conductive rod 414 passes and is fixedly mounted on the end surface of the front tube 411. One end of the first conductive rod 414 is fixedly connected to and electrically connected to a metal sheet 415 within the discharge chamber, while the other end extends beyond the protrusion on the end surface of the front tube 411. A portion of the first conductive rod 414 and one end of the first metal adjustment member 417 are disposed within a first metal sleeve 416, which is fixedly connected to the protrusion on the end surface of the front tube. A first spring 418 is disposed between the first metal adjustment member 417 and the first conductive rod 414. The first metal sleeve 416, first metal adjustment member 417, and first conductive rod 414 are coaxially arranged. As the first metal adjustment member 417 moves up and down along the axis, it maintains electrical contact with the first conductive rod 414. A first metal mounting seat 419 is fixedly mounted on the bottom surface of the rear tube 412. This first metal mounting seat 419 is connected to one end of the connecting rod 47. The base of the metal needle 413 is fixedly connected and electrically connected to the first metal mounting seat 419, with its tip facing the metal plate 415. During operation, the tip discharge model is pushed forward as a whole. When the first metal adjustment member 217 contacts the conductive disk 18, a tip discharge is generated. During this contact, the first spring 218 cushions the pressure of the tip discharge model, protecting the model.

[0027] like Figure 6As shown, the suspended discharge model includes an insulating tube 421 and an insulating seat 422. The insulating seat 422 is fixedly connected to the open end of the insulating tube 421. The insulating tube 421 and the insulating seat 422 enclose a discharge chamber. A metal dummy 423 is located within the discharge chamber and fixedly mounted on the insulating seat 422. A protrusion is provided on the end surface of the insulating tube 421, through which a second conductive rod 424 passes. One end of the second conductive rod 424 extends into the discharge chamber, while the other end extends beyond the protrusion on the end surface of the insulating tube 421. The metal dummy 423 corresponds to the second conductive rod 424, with a gap between them. A portion of the second conductive rod 424 and one end of the second metal adjustment member 425 are located within a second metal sleeve 426, which is fixedly connected to the protrusion on the end surface of the insulating tube. A second spring 427 is located between the second metal adjustment member 425 and the second conductive rod 424. The second metal sleeve 426, the second metal adjustment member 425, and the second conductive rod 424 are coaxially arranged. As the second metal adjustment member 425 moves up and down along this axis, it maintains electrical contact with the second conductive rod 424. A second metal mounting base 428 is fixed to the insulating base 422 and connected to one end of the connecting rod 47. The second metal mounting base 428 is insulated from the metal simulation member 423 by the insulating base 422. During operation, the suspended discharge model is pushed forward as a whole. When the second metal adjustment member 425 contacts the conductive disk 18, a suspended discharge is generated. During this contact, the second spring 427 cushions the pressure of the suspended discharge model, protecting the model.

[0028] like Figure 7As shown, the air-gap discharge model includes a first insulating block 431, a first metal rod 432, and a third conductive rod 433. The first insulating block 431 is made of solid polyester with air bubbles dispersed within it. The first metal rod 432 and the third conductive rod 433 extend from either side of the first insulating block 431. The heads of the first metal rod 432 and the third conductive rod 433 are positioned opposite each other and insulated by the first insulating block 431. Portions of the third conductive rod 433 and one end of the third metal adjustment member 434 are positioned within a third metal sleeve 435, which is fixedly connected to the first insulating block 431. A third spring 436 is interposed between the third metal adjustment member 434 and the third conductive rod 433. The third metal sleeve 435, the third metal adjustment member 434, and the third conductive rod 433 are coaxially arranged. As the third metal adjustment member 434 moves up and down along this axis, it maintains electrical contact with the third conductive rod 433. The third metal mounting base 437 is fixedly mounted on the first insulating block 431 and is fixedly connected to and electrically conductive with the first metal rod 432. The third metal mounting base 437 is connected to one end of the connecting rod 47. During operation, the air gap discharge model is pushed forward as a whole. When the third metal adjustment member 434 contacts the conductive disk 18, an air gap discharge is generated. During this contact between the air gap discharge model and the conductive disk 18, the third spring 436 provides a buffering effect, protecting the model.

[0029] like Figure 8 As shown, the creeping discharge model includes a second insulating block 441, a second metal rod 442, and a fourth conductive rod 443. The second insulating block 441 is made of solid polyester and is supported by two insulating plates 448. The two insulating plates 448 are arranged parallel to each other, with their planes perpendicular to the central axis of the creeping discharge model. The second metal rod 442 and the fourth conductive rod 443 extend from either side of the second insulating block 441 into the second insulating block 441. The heads of the second metal rod 442 and the fourth conductive rod 443 are positioned opposite each other and insulated by the second insulating block 441. A portion of the fourth conductive rod 443 and one end of the fourth metal adjustment member 444 are positioned within a fourth metal sleeve 445, which is fixedly connected to the second insulating block 441. A fourth spring 446 is disposed between the fourth metal adjustment member 444 and the fourth conductive rod 443. The fourth metal sleeve 445, fourth metal adjustment member 444, and fourth conductive rod 443 are coaxially arranged. As the fourth metal adjustment member 444 moves up and down along this axis, it maintains electrical contact with the fourth conductive rod 443. A fourth metal mounting seat 447 is fixedly mounted on the second insulating block 441 and is fixedly connected and electrically conductive to the second metal rod 442. The fourth metal mounting seat 447 is connected to one end of the connecting rod 47. During operation, the entire surface discharge model is pushed forward. When the fourth metal adjustment member 444 contacts the conductive disk 18, surface discharge is generated. During contact between the surface discharge model and the conductive disk 18, the fourth spring 446 provides pressure relief to protect the model.

[0030] The specific working steps are as follows: Step (1) Cable connection: If you need to simulate partial discharge at the middle joint of the cable, connect one end of the two cables to be tested to two cable joints respectively, and the shielding layer and armor layer of the cable are grounded; if you need to simulate partial discharge at the terminal joint of the cable, connect one end of the cable to be tested to one cable joint, and the shielding layer and armor layer of the cable are grounded.

[0031] Step (2) local discharge type simulation: different types of local discharge models (surface, suspension, tip or air gap) are selected as test discharge models on the centralized control platform of the PC host computer to simulate the discharge of the power cable. For example, the "manual closing" parameter of the tip discharge model is selected, and the PC host computer sends a command to the electrode controller. The electrode controller executes the PWM signal to drive the stepper motor screw corresponding to the tip discharge model to rotate clockwise, driving the tip discharge model to move forward. The head of the tip discharge model touches the conductive disk, that is, it is connected to the conductive rod, generating local discharge at the cable tip.

[0032] Step (3) Controlling the magnitude of partial discharge: Enter any step from 1V to 10V in the "Voltage Adjustment Amplitude" parameter on the PC-side host computer centralized control platform. Select the "Boost" parameter multiple times. The PC-side host computer sends a step-by-step voltage-boosting command signal to the digital control voltage-regulating power supply. The digital control voltage-regulating power supply executes the received PWM signal to accurately and slowly adjust the boost value, precisely controlling the magnitude of partial discharge in the power cable.

[0033] Step (4) Switching the simulated partial discharge type model: After selecting the "Reduced Voltage to 0V" parameter on the PC host computer centralized control platform, select the "Manual Separation" parameter for the current test discharge model on the PC host computer centralized control platform. The PC host computer sends a command to the electrode controller. The electrode controller executes the PWM signal to drive the stepper motor corresponding to the test discharge model to rotate counterclockwise, driving the test discharge model to move backward and separate from the conductive disk. Switch to the next test discharge model on the PC host computer centralized control platform, and repeat the operation to complete the switching of the simulated partial discharge model type.

Claims

1. An integrated control method for simulating partial discharge of power cables, characterized by: The method is to apply high voltage to the detection point of the power cable to be tested, and simulate partial discharge at the detection point through a partial discharge model. The type and size of the simulated partial discharge are controlled by an external PC end. The partial discharge detector receives the partial discharge signal and sends it to the PC end. The detection location is the terminal joint or intermediate joint of the cable to be tested; if partial discharge at the cable terminal joint is simulated, high voltage is applied to the end of one cable, and partial discharge is simulated at the cable end using a partial discharge model, with the shielding layer and armor layer of the cable grounded; if partial discharge at the cable intermediate joint is simulated, one end of the two cables are connected and conducted, high voltage is applied at the connection, and partial discharge is simulated at the connection using a partial discharge model, with the shielding layer and armor layer of both cables grounded; The application of high voltage is achieved through a digitally controlled voltage-regulating power supply and a transformer. The PC controls the switch of the digitally controlled voltage-regulating power supply and controls the voltage step-up and step-down amplitude of the transformer through the digitally controlled voltage-regulating power supply. The PC side controls the linear motion of the partial discharge model. When the head of the partial discharge model touches the detection point, partial discharge is generated.

2. A power cable partial discharge simulation device for implementing the method according to claim 1, characterized in that: It includes a simulated partial discharge tube, a control cabinet and a partial discharge model component; the simulated partial discharge tube is arranged above the control cabinet, and the partial discharge model component is arranged on the simulated partial discharge tube; The simulated partial discharge cylinder comprises three coaxially arranged parts: a left cylinder, a middle cylinder, and a right cylinder; the left cylinder and the right cylinder are both closed at one end by an end cap, and the other end is connected to the middle cylinder; the two end caps are respectively provided with a cable connector, and the left cylinder and the right cylinder are respectively provided with a conductive rod, the two conductive rods are located in the same straight line, one end of the two conductive rods is connected to the corresponding cable connector, and the other end is arranged opposite to each other in the middle cylinder; a conductive disk is provided in the middle cylinder, and a conductive column is fixedly provided on the conductive disk, the conductive column is arranged perpendicular to the conductive rod, and the ends of the two conductive rods are both connected to the conductive column; The control cabinet is provided with a digitally controlled voltage-regulating power supply, a transformer, an electrode controller, a coupling capacitor, a detection impedance, and a partial discharge detector; the digitally controlled voltage-regulating power supply is connected to the low-voltage side input end of the transformer, and the digitally controlled voltage-regulating power supply is controlled by an external PC end; one end of the coupling capacitor is connected to the high-voltage side output end of the transformer, and the other end of the coupling capacitor is connected to the partial discharge detector through the detection impedance, the partial discharge detector detects the discharge type and discharge size data in real time, and the partial discharge detector is connected to the external PC end; the electrode controller is connected to the PC end, and the PC end sends a control signal to the electrode controller to control the partial discharge model component; the high-voltage side output end of the transformer is connected to the conductive column through a cable; The partial discharge model assembly includes multiple partial discharge models arranged in parallel. The multiple partial discharge models are controlled to extend and retract by respective stepping motors. The multiple partial discharge models are arranged corresponding to the conductive disks, and the movement direction is perpendicular to the plane of the conductive disks. When the head of the partial discharge model touches the conductive disk, partial discharge is generated.

3. The integrated control power cable partial discharge simulation method according to claim 1, characterized in that: The PC end controls the voltage step-up and step-down of the transformer, and the voltage adjustment step is optional in the range of 1-10V.

4. The integrated control power cable partial discharge simulation method according to claim 1, characterized in that: The local discharge model is one or more of a tip discharge model, a suspension discharge model, an air gap discharge model, and a surface discharge model.

5. The power cable partial discharge simulation device according to claim 2, characterized in that: The partial discharge model assembly also includes a model tube, which is fixedly arranged on the middle cylinder and is arranged in a three-way manner with the middle cylinder; a model bracket is arranged in the model tube, and each partial discharge model is fixed to the model bracket through its own corresponding stepping motor, and the model bracket is fixed in the model tube; the stepping motor is connected to the electrode controller, and the PC end controls each stepping motor through the electrode controller, thereby controlling the expansion and contraction of each partial discharge model.

6. The power cable partial discharge simulation device according to claim 2, characterized in that: The multiple local discharge models are one or more of a tip discharge model, a suspension discharge model, an air gap discharge model, and a creeping discharge model.

7. The power cable partial discharge simulation device according to claim 2, characterized in that: A support frame is provided in the simulated partial discharge tube, and two conductive rods are fixed in the simulated partial discharge tube through the support frame.

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