Multi-sample insulation and voltage resistance test system for insulating material

Abstract

The invention discloses a multi-sample insulation and voltage resistance test system of an insulation material, the system comprises a protection inductor and a plurality of test units, each test unit comprises a high-voltage relay, a high-voltage electrode, a low-voltage electrode, a detection impedance circuit, a protection resistor, an insulation support and a voltage monitoring unit, the protection inductor is preposed in the system, and the protection resistor is moved backwards; the high-voltage relay obtains power through the protection inductor, the high-voltage electrode is connected with the high-voltage relay, and the insulating material is arranged between the low-voltage electrode and the high-voltage electrode. The high-voltage end of the detection impedance circuit is connected with the low-voltage electrode, and the low-voltage end of the detection impedance circuit is grounded; the voltage monitoring unit is connected with the high-voltage end of the detection impedance circuit to monitor whether the voltage of the high-voltage end exceeds a preset value; and the circuit control end of the voltage monitoring unit is connected with the controlled end of the high-voltage relay, so that the high-voltage relay is in an off state when the voltage of the high-voltage end exceeds a preset value. According to the system, the test efficiency of the withstand voltage breakdown test of the insulating material can be enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of power grid safety, and in particular to a multi-sample insulation withstand voltage testing system for insulating materials. Background Art

[0002] As the demand for electricity in the whole society is increasing, people's requirements for the operational stability of the power system are also increasing, and the operational stability of power transformers plays an important role in the stable operation of the power system. The insulating materials used in power transformers mainly adopt the oil-paper insulation system, which can achieve electrical isolation between high, medium and low voltage windings and electrical isolation between metal box bodies, and play an important role in the safe operation of various power equipment in the power grid system. Therefore, in order to ensure the stable operation of power transformer equipment under long-term energized operation, it is generally necessary to conduct status detection of the equipment insulation materials during the equipment design, manufacturing and operation and maintenance stages. Among the many tests, the withstand voltage breakdown test of the insulation material is the simplest and most direct method to evaluate the status of the insulation material of the power equipment. In the process of selecting the insulation material of the power transformer equipment, optimizing the manufacturing process and operating and maintaining the equipment, corresponding tests will be carried out in accordance with the corresponding national standards and enterprise standards.

[0003] At present, the withstand voltage breakdown test of insulating materials is mostly carried out through an insulating multi-sample withstand voltage breakdown device. The test circuits where the test electrodes of each insulating material are set are connected in parallel. However, when one insulating material sample in the multiple circuits is broken down, other non-breakdown samples will have instantaneous overvoltage and the steady-state voltage will be forced to drop to zero due to the parallel relationship. At this time, it generally takes a period of time to increase the voltage and maintain it, which greatly prolongs the time required for the test. In addition, the instantaneous overvoltage when any sample breaks down will damage the non-breakdown insulating material samples, forcing the staff to handle the insulating material, seriously affecting the normal progress of the test and seriously reducing the efficiency of the withstand voltage breakdown test of the insulating material. Summary of the invention

[0004] In view of this, the present application provides a multi-sample insulation withstand voltage test system for insulating materials. The main purpose is to achieve continuous withstand voltage breakdown testing of multiple samples without power outage by not changing the voltage distribution on the samples in other test units when a sample in any test unit breaks down, so as to solve the technical problem of low efficiency of withstand voltage breakdown testing of insulating materials.

[0005] According to a first aspect of the present invention, there is provided a multi-sample insulation withstand voltage test system for insulating materials, the system comprising a protection inductor and a plurality of test units connected in parallel;

[0006] The first end of the protection inductor is used to connect to an external high-voltage power supply to obtain a test voltage and provide instantaneous current protection for each of the test units;

[0007] The test unit includes a high voltage relay, a high voltage electrode, a low voltage electrode, a protection resistor, a detection impedance circuit, a voltage monitoring unit and an insulating bracket;

[0008] The first connection end of the high-voltage relay is connected to the second end of the protection inductor to obtain a test voltage;

[0009] The high-voltage electrode is connected to the second connection end of the high-voltage relay, and an insulating material to be tested is arranged between the low-voltage electrode and the high-voltage electrode;

[0010] The protection resistor is connected in series between the low voltage electrode and the high voltage end of the detection impedance circuit to protect the test unit from overvoltage, and the low voltage end of the detection impedance circuit is grounded;

[0011] The voltage acquisition terminal of the voltage monitoring unit is arranged at the high voltage terminal of the detection impedance circuit to monitor the voltage value of the high voltage terminal voltage of the high voltage terminal;

[0012] The circuit control end of the voltage monitoring unit is connected to the controlled end of the high-voltage relay, so that when the voltage value of the high-voltage terminal voltage is greater than or equal to the preset judgment voltage value, the high-voltage relay is in an off state, so as to isolate the test unit where the high-voltage relay is located from the system;

[0013] The low-voltage electrode is arranged on the outside of the insulating bracket, and the protective resistor and the detection impedance circuit are arranged inside the insulating bracket, so that the low-voltage electrode, the protective resistor and the detection impedance circuit are fixed in the test unit through the insulating bracket, so that the voltage between the low-voltage electrode, the protective resistor and the detection impedance circuit and the grounding point of the system is isolated.

[0014] Optionally, the detection impedance circuit includes a diode, a capacitor, a fixed resistor and a variable resistor; the connection end after the negative end of the diode, the first end of the capacitor, the first end of the fixed resistor and the first end of the variable resistor are connected in parallel serves as the high voltage end of the detection impedance circuit and is connected to the protection resistor; the connection end after the positive end of the diode, the second end of the capacitor, the second end of the fixed resistor and the second end of the variable resistor are connected in parallel is grounded as the low voltage end of the detection impedance circuit.

[0015] Optionally, the voltage monitoring unit includes a voltage comparator, a trigger and a solid-state relay; the first access end of the voltage comparator is connected to the high-voltage end of the detection impedance circuit to collect the voltage value of the high-voltage end voltage, the second access end of the voltage comparator is used to access the preset judgment voltage value, and the output end of the voltage comparator sends a high-level pulse signal when the voltage value of the high-voltage end voltage is greater than or equal to the preset judgment voltage value; the access end of the trigger is connected to the output end of the voltage comparator, and the control output end of the trigger is connected to the access end of the solid-state relay. When the trigger obtains the high-level pulse signal, the signal output end of the trigger sends a breakdown trigger signal and sends a switch disconnection signal to the solid-state relay; the switch control end of the solid-state relay is connected to the controlled end of the high-voltage relay so that the high-voltage relay is in a disconnected state when the switch disconnection signal is received.

[0016] Optionally, the voltage monitoring unit also includes a photoelectric isolator; the first end of the photoelectric isolator is connected to the high voltage end of the detection impedance circuit, and the second end of the photoelectric isolator is connected to the first access end of the voltage comparator to establish electrical isolation between the detection impedance circuit and the voltage comparator.

[0017] Optionally, the system further comprises a high-voltage power supply; a power output terminal of the high-voltage power supply is connected to a first terminal of the protection inductor to supply power to each of the test units via the protection inductor.

[0018] Optionally, the system further includes a controller; the controller is connected to the voltage monitoring unit and the high-voltage power supply to obtain the breakdown trigger signal and control the working state of the high-voltage power supply.

[0019] Optionally, the system also includes an audible and visual alarm unit; the audible and visual alarm unit is connected to the controller; the controller is configured to perform the following processing: real-time monitoring of whether the test unit sends out the breakdown trigger signal; when the test unit sends out the breakdown trigger signal, sending out audible and visual prompt information including identification information of the test unit.

[0020] Optionally, the controller is configured to perform the following processing: in response to a received breakdown trigger signal, determine the test unit that issues the breakdown trigger signal; determine the length of time from when the high-voltage power supply starts to issue a test voltage to when the breakdown trigger signal issued by the test unit is received; and determine the length of time as the insulation life time of the insulating material in the test unit.

[0021] Optionally, the system further comprises a remote communication module; the remote communication module is connected to the controller and is used to establish a communication connection between the controller and a remote host computer.

[0022] Optionally, the remote communication module establishes a communication connection with the host computer via a cellular network.

[0023] The present invention provides a multi-sample insulation withstand voltage test system for insulating materials, which provides instantaneous current protection for each test unit through a protective inductor, and connects a protective resistor in series between a low-voltage electrode and a high-voltage end of a detection impedance circuit to protect the test unit from overvoltage. At the same time, an insulating bracket is used to set a low-voltage electrode to achieve ground isolation of the low-voltage electrode when it carries high voltage after the oil-paper insulation is broken down, thereby protecting the circuit safety of the system. When conducting the test, the insulating material to be tested is set between the high-voltage electrode and the low-voltage electrode of the test unit, and the voltage is obtained from the outside through a high-voltage relay that can be turned on and off, so as to perform a withstand voltage breakdown test on the insulating material. When the tested insulating material breaks down, the voltage at the high-voltage end of the detection impedance circuit will increase. When the voltage monitoring unit detects that the voltage value of the high-voltage end of the detection impedance circuit reaches the judgment value of the insulation material sample breakdown, the high-voltage relay is controlled to disconnect, and the broken-down insulating material is isolated from the test circuits of other test units, so as to isolate the test unit with insulation breakdown from the high-voltage withstand voltage breakdown test circuit, avoid affecting the test work of other samples that have not been broken down, and significantly improve the efficiency of the withstand voltage breakdown test of the insulating material.

[0024] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0026] Figure 1 A schematic diagram showing an equivalent circuit of an existing insulating multi-sample withstand voltage breakdown device provided by an embodiment of the present invention;

[0027] Figure 2 One of the structural schematic diagrams of a multi-sample insulation withstand voltage test system for insulating materials provided by an embodiment of the present invention is shown;

[0028] Figure 3 A schematic structural diagram of an impedance detection circuit provided by an embodiment of the present invention is shown;

[0029] Figure 4 A second structural schematic diagram of a multi-sample insulation withstand voltage test system for insulating materials provided by an embodiment of the present invention is shown;

[0030] Figure 5 A third structural schematic diagram of a multi-sample insulation withstand voltage test system for insulating materials provided by an embodiment of the present invention is shown;

[0031] Figure 6 A schematic diagram showing an equivalent circuit of a multi-sample insulation withstand voltage test system for insulating materials provided by an embodiment of the present invention;

[0032] Figure 7 A schematic diagram showing the circuit principle of a multi-sample insulation withstand voltage test system for insulating materials provided by an embodiment of the present invention when the insulating materials are not broken down;

[0033] Figure 8 A schematic diagram showing the circuit principle of a multi-sample insulation withstand voltage testing system for insulating materials provided by an embodiment of the present invention when the insulating material is broken down. DETAILED DESCRIPTION

[0034] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0035] The current dielectric breakdown test of insulating materials is mostly carried out through a dielectric multi-sample dielectric breakdown device. Each test circuit where the test electrodes of the insulating materials are set is connected in parallel. However, when one of the insulating material samples in the multi-circuit is broken down, other samples that have not been broken down will have transient overvoltage and the steady-state voltage will be forced to drop to zero due to the parallel relationship, which will affect the normal progress of the test. Specifically, Figure 1 As shown, the existing insulation multi-sample withstand voltage breakdown device includes multiple test loops connected in parallel, each test loop is used to set an insulation material sample T, the insulation material sample T in the test loop is connected in series with an impedance Z, and the impedance value Z of each impedance Z is 采 Much smaller than the resistance of the circuit protection resistor R 保 Furthermore, the high voltage source outputs a test voltage of Vout. When the insulating material sample T of a test loop is broken down, the sample voltage V on the insulating material sample T of the test loop is 样 And the impedance Z 样The voltage at the high-voltage end of the impedance Z of the test circuit is approximately equal to zero, which in turn causes the voltage at the high-voltage end of the insulating material sample T of other test circuits to be approximately equal to zero; further, the overvoltage at the moment of breakdown of any sample will damage the insulating material samples that have not been broken down, forcing the staff to handle the insulating multi-sample withstand voltage breakdown device, seriously reducing the efficiency of the withstand voltage breakdown test of the insulating material.

[0036] In view of the above problems, in one embodiment, Figure 2 As shown, a multi-sample insulation withstand voltage test system for insulating materials is provided. The insulation withstand voltage test of high-voltage maintaining oil paper as an insulating material is taken as an example for explanation. The system includes a protective inductor and multiple test units, each test unit is used to perform an insulation withstand voltage test on a portion of insulating material, thereby realizing voltage distribution on the insulating material sample.

[0037] Furthermore, each test unit includes a high-voltage relay, a high-voltage electrode, a low-voltage electrode, a detection impedance circuit, a protection resistor, an insulating bracket, and a voltage monitoring unit. Specifically, the first end of the protection inductor is used to connect to a high-voltage power supply to obtain a test voltage. Furthermore, the second end of the protection inductor is connected to the first connection end of the high-voltage relay of each of the test units to provide instantaneous current protection for each of the test units.

[0038] Furthermore, the high-voltage electrode is connected to the second connection end of the high-voltage relay, and the insulating material is arranged between the low-voltage electrode and the high-voltage electrode. In the actual testing process, the insulating material can be clamped by the high-voltage electrode and the low-voltage electrode for testing.

[0039] Furthermore, the protection resistor is connected in series between the low-voltage electrode and the high-voltage end of the detection impedance circuit to protect the test unit from overvoltage. Here, one end of the protection resistor is connected to the low-voltage electrode, and the other end of the protection resistor is connected to the high-voltage end of the detection impedance circuit, which is used to bear the high voltage of the insulation material sample breakdown and prevent the current in the test unit from exceeding the maximum output current set by the high-voltage power supply, thereby improving the operating stability of the test system.

[0040] Furthermore, the high voltage end of the detection impedance circuit is connected to the protection resistor, and the low voltage end of the detection impedance circuit is grounded. The voltage value between the high voltage end and the low voltage end of the detection impedance circuit is the judgment value of the insulation material sample breakdown. When the insulation material breaks down, the voltage value between the high voltage end and the low voltage end increases instantly.

[0041] Furthermore, the voltage acquisition end of the voltage monitoring unit is arranged at the high-voltage end of the detection impedance circuit, and the voltage acquisition end can be connected to the high-voltage end of the detection impedance circuit to monitor whether the voltage value of the high-voltage end voltage of the high-voltage end is greater than or equal to the preset judgment voltage value, and when the voltage value of the high-voltage end voltage is greater than or equal to the preset judgment voltage value, a breakdown trigger signal is sent to the outside; here, the preset judgment voltage value is used to calibrate the judgment amount of the insulation material sample breakdown, and its specific value can be determined according to the actual situation. Furthermore, when it is determined that the sample has a breakdown phenomenon, a breakdown trigger signal can be generated and sent to an external controller or other test control device, so that the controller and other devices can perform functions such as synchronous control reset and breakdown timing monitoring.

[0042] Furthermore, the circuit control end of the voltage monitoring unit is connected to the controlled end of the high-voltage relay, so that when the voltage value of the high-voltage end voltage is greater than or equal to the preset judgment voltage value, the high-voltage relay is in a disconnected state, so as to isolate the test unit where the high-voltage relay is located from the system, isolate the broken-down insulating material from the test circuits of other test units, and isolate the test unit with insulation breakdown from the high-voltage withstand voltage breakdown test circuit. Here, the controlled end of the high-voltage relay can be the control coil end of the relay.

[0043] Furthermore, the low-voltage electrode is arranged on the outside of the insulating bracket, and the protective resistor and the detection impedance circuit are arranged inside the insulating bracket, so that the low-voltage electrode, the protective resistor and the detection impedance circuit are fixed in the test unit through the insulating bracket, so that the voltage between the low-voltage electrode, the protective resistor and the detection impedance circuit and the grounding point of the system is isolated; further, the wire leading out of the protective resistor can pass through the insulating bracket to be connected to the low-voltage electrode, and the wire leading out of the voltage monitoring unit can pass through the insulating bracket to be connected to the detection impedance circuit.

[0044] Here, the insulating bracket is used to set the low-voltage electrode and realize the isolation of the low-voltage electrode from the ground when it carries high voltage after the oil-paper insulation is broken down. Here, the insulating bracket is used to achieve sufficient withstand voltage strength between the low-voltage electrode and the ground potential of the test unit, and realize the isolation from the ground when it carries high voltage after the insulation material is broken down; further, the protective resistor is placed on the low-voltage electrode side, which can withstand the high voltage when the insulation material sample is broken down. When the insulation material sample in any test unit breaks down and short-circuits, the low-voltage electrode and the high-voltage end of the protective resistor maintain the same potential high voltage with the high-voltage electrode of the test unit that has not broken down, thereby maintaining the voltage distribution on the insulation material sample in the test unit that has not broken down unchanged, so that the system does not have the problem of forced short circuit.

[0045] The multi-sample insulation withstand voltage test system for insulating materials provided by the present invention provides instantaneous current protection for each test unit through a protective inductor, and connects a protective resistor in series between a low-voltage electrode and a high-voltage end of a detection impedance circuit to perform overvoltage protection on the test unit. At the same time, an insulating bracket is used to set a low-voltage electrode to achieve ground isolation of the low-voltage electrode when it carries high voltage after the insulating material breaks down, thereby protecting the circuit safety of the system. When conducting the test, the insulating material to be tested is set between the high-voltage electrode and the low-voltage electrode, and the voltage is obtained from the outside through a high-voltage relay that can be turned on and off, so as to perform a withstand voltage breakdown test on the insulating material. When the insulating material breaks down, the voltage at the high-voltage end of the detection impedance circuit will increase. When the voltage monitoring unit detects that the voltage value at the high-voltage end of the detection impedance circuit reaches the judgment value of the insulation material sample breakdown, the high-voltage relay is controlled to be disconnected, and the broken-down insulating material is isolated from the test circuits of other test units, so as to isolate the test unit with insulation breakdown from the high-voltage withstand voltage breakdown test circuit to avoid affecting the test work of other non-breakdown samples, and to achieve that after any sample is tested and broken down, other non-breakdown samples still maintain a high-voltage state, and the withstand voltage breakdown test of other samples is continuously performed without power failure, which not only solves the damage of instantaneous overvoltage to non-breakdown samples, but also reduces the error between the insulation life obtained by the power-on timing after power failure and the continuous test timing of a single sample, and significantly improves the efficiency of the withstand voltage breakdown test of the insulating material.

[0046] Further, such as Figure 3 As shown, the detection impedance circuit includes a diode, a capacitor, a fixed resistor and a variable resistor; specifically, the connection end after the negative terminal of the diode, the first end of the capacitor, the first end of the fixed resistor and the first end of the variable resistor are connected in parallel serves as the high voltage end of the detection impedance circuit and is connected to the protection resistor; further, the connection end after the positive terminal of the diode, the second end of the capacitor, the second end of the fixed resistor and the second end of the variable resistor are connected in parallel serves as the low voltage end of the detection impedance circuit and is grounded. The voltage acquisition end of the voltage monitoring unit can be connected to the high voltage end of the detection impedance circuit to collect the voltage value of the high voltage end voltage of the high voltage end of the detection impedance circuit.

[0047] In an optional embodiment, if Figure 4As shown, the voltage monitoring unit includes a voltage comparator, a trigger and a solid-state relay; specifically, the first access end of the voltage comparator is connected to the high-voltage end of the detection impedance circuit to collect the voltage value of the high-voltage end voltage, the second access end of the voltage comparator is used to access the preset judgment voltage value, and the output end of the voltage comparator sends a high-level pulse signal when the voltage value of the high-voltage end voltage is greater than or equal to the preset judgment voltage value; relatively, the voltage comparator sends a low-level pulse signal when the voltage value of the high-voltage end voltage is less than the preset judgment voltage value; here, when the insulating material in the test unit where the voltage monitoring unit is located is broken down, the voltage value of the high-voltage end voltage will be greater than or equal to the preset judgment voltage value, at this time, the output end of the voltage comparator sends a high-level pulse signal; relatively, when the insulating material in the test unit where the voltage monitoring unit is located is not broken down, the voltage value of the high-voltage end voltage is less than the preset judgment voltage value, at this time, the output end of the voltage comparator sends a low-level pulse signal.

[0048] Furthermore, the access end of the trigger is connected to the output end of the voltage comparator, and the control output end of the trigger is connected to the access end of the solid-state relay. When the trigger obtains the high-level pulse signal, the signal output end of the trigger sends a breakdown trigger signal and sends a switch disconnection signal to the solid-state relay; further, when the trigger obtains the high-level pulse signal, it sends a breakdown trigger signal to the outside.

[0049] Furthermore, the switch control end of the solid-state relay is connected to the controlled end of the high-voltage relay, so that when the switch disconnection signal is received, the high-voltage relay is in a disconnected state to isolate the insulating material in the test unit from the test system. In the embodiment provided by the present application, at the moment when the trigger outputs the breakdown trigger signal, the coil current of the high-voltage relay is disconnected, and the high-voltage switch of the high-voltage relay is disconnected, so that the test unit containing the broken-down insulating material is withdrawn from the high-voltage withstand voltage breakdown test loop, and the normal progress of the test is ensured.

[0050] In an optional embodiment, if Figure 5As shown, the voltage monitoring unit also includes a photoelectric isolator; specifically, the first end of the photoelectric isolator is connected to the high voltage end of the detection impedance circuit, and the second end of the photoelectric isolator is connected to the first access end of the voltage comparator to establish electrical isolation between the detection impedance circuit and the voltage comparator. Furthermore, the high-voltage relay, high-voltage electrode, low-voltage electrode, detection impedance circuit, protection resistor and insulating bracket in the test unit can be determined as the electrode system of the test unit, and the electrode system is electrically isolated between the voltage monitoring units through the photoelectric isolator. The embodiment provided in the present application can realize the electrical isolation of the voltage monitoring unit and the electrode system, prevent the high voltage of the electrode system from interfering with and damaging the voltage monitoring unit, and monitor the voltage value on the detection impedance circuit.

[0051] In an optional embodiment, if Figure 5 As shown, the system also includes a high-voltage power supply and a controller. The power output end of the high-voltage power supply is connected to the first end of the protection inductor to power each of the test units through the protection inductor; further, the controller is connected to the voltage monitoring unit and the high-voltage power supply to obtain the breakdown trigger signal and control the working state of the high-voltage power supply. Here, the working state of the high-voltage power supply can be controlled by the controller, and the output level of the trigger can be monitored, and synchronous control reset and breakdown timing monitoring can also be performed.

[0052] Further, the system also includes an audible and visual alarm unit; here, the audible and visual alarm unit is connected to the controller; further, the controller is configured to perform the following processing: first, monitor in real time whether the test unit sends the breakdown trigger signal; then, when the test unit sends the breakdown trigger signal, send out audible and visual prompt information including the identification information of the test unit. The embodiment provided by the present application can control the operation of the system based on the controller, and send out audible and visual prompt information when a test unit sends a breakdown trigger signal, so that relevant staff can promptly understand the breakdown of the insulating material and the test progress of the insulation withstand voltage test.

[0053] In an optional embodiment, the controller is configured to perform the following processing: first, in response to the received breakdown trigger signal, determine the test unit that sends the breakdown trigger signal; then, determine the length of time from when the high-voltage power supply starts to send the test voltage to when the breakdown trigger signal sent by the test unit is received; specifically, the timing can be started from the start of the test when the high-voltage power supply supplies power to the test unit, and when a breakdown trigger signal sent by a test unit is received, calculate the length of time from when the test starts to when the breakdown trigger signal is received. Finally, the time length is determined as the insulation life time of the insulating material in the test unit. The embodiment provided by the present application can accurately calculate the insulation life time of the insulating material in each test unit and efficiently perform breakdown timing monitoring of the insulating material.

[0054] Furthermore, the system also includes a remote communication module (not shown in the figure); the remote communication module is connected to the controller and is used to establish a communication connection between the controller and a remote host computer, so as to remotely debug and control the controller through the host computer, and receive prompt information sent by the controller to remotely manage the system. Further, the remote communication module establishes a communication connection with the host computer through a cellular network. Here, the host computer can be a mobile terminal held by relevant test personnel, such as a mobile phone or other device. The controller can send the test results and parameters to the mobile phone of the relevant personnel, so that the relevant personnel can control the test work anytime and anywhere.

[0055] Furthermore, in the actual testing process, a specific number of test units can be connected to the testing system based on the number of insulating material samples to be tested, each insulating material sample is set between the high-voltage electrode and the low-voltage electrode of a test unit, and a high-voltage power supply is used to power each test unit.

[0056] After the test starts, the photoelectric isolator in the voltage monitoring unit is connected to the high-voltage end of the detection impedance circuit of the electrode system to achieve electrical isolation between the voltage monitoring unit and the electrode system, prevent the high voltage of the electrode system from interfering with and damaging the voltage monitoring unit, and monitor the voltage value on the high-voltage end of the detection impedance circuit; further, the voltage comparator is connected to the photoelectric isolator to determine whether the voltage value at the high-voltage end of the detection impedance circuit transmitted by the photoelectric isolator reaches the determination value when the insulating material sample is broken down. When the insulating material sample is not broken down, the voltage comparator outputs a low level, and when the insulating material sample is broken down, the voltage comparator outputs a pulse high level; further, the trigger is respectively connected to the output end of the voltage comparator, the access end of the solid-state relay and the controller, where the trigger monitors the output level of the voltage comparator to control the switching state of the solid-state relay and provides a breakdown trigger signal for the controller; the switch control end of the solid-state relay is connected to the controlled end of the high-voltage relay, and at the moment when the trigger outputs the breakdown trigger signal of the insulating material sample, the coil current of the high-voltage relay is disconnected, and the high-voltage switch of the high-voltage relay is disconnected, so as to realize that the electrode system containing the broken-down insulating material sample is withdrawn from the high-voltage withstand voltage breakdown test loop.

[0057] Further, such as Figure 6 As shown, the multiple insulating material samples are respectively the first insulating material sample T1, the second insulating material sample T2...the Nth insulating material sample Tn, the protection resistors of each test unit are respectively the first protection resistor R1, the second protection resistor R2...the Nth protection resistor Rn, and the detection impedance circuit of each test unit is respectively the first detection impedance circuit Z1, the second detection impedance circuit Z2...the Nth detection impedance circuit Zn; further, each insulating material sample is respectively placed between the high voltage electrode and the low voltage electrode in different test units; further, further, as Figure 7 and Figure 8 As shown, the current flowing into each test unit from the high voltage power supply is i 样1 、i 样2 ……i 样n , the voltage of the first insulating material sample T1 is V 样1 , the impedance of the first insulating material sample T1 is Z 样1 , the resistance of the first protection resistor R1 is R 保1 , the impedance of the first detection impedance circuit Z1 is Z 采1 ; V 样1 By Z 样1 , R 保1 and Z 采1 Furthermore, the voltage to which the second insulating material sample T2 is subjected is V 样2 , the impedance of the second insulating material sample T2 is Z 样2 , the resistance of the second protection resistor R2 is R 保2, the voltage that the Nth insulating material sample Tn bears is V 样n , the impedance of the Nth insulating material sample Tn is Z 样n , the resistance of the Nth protection resistor Rn is R 保n .

[0058] Further, such as Figure 7 As shown, when the first insulating material sample T1 is not broken down, in the test unit where the first insulating material sample T1 is located, the impedance Z of the first insulating material sample T1 is 样1 Much larger than the resistance of the first protection resistor R1 保1 , the resistance value of the first protection resistor R1 is R 保1 Much larger than the impedance Z of the first detection impedance circuit Z1 采1 , the voltage V that the first insulating material sample T1 withstands 样1 Approximately equal to the output voltage V of the high voltage power supply 输出 : In the test unit where the second insulating material sample T2 is located, the impedance Z of the second insulating material sample T2 样2 Much larger than the resistance value R of the second protection resistor R2 保2 , the resistance value of the second protection resistor R2 is R 保2 Much larger than the impedance Z of the second detection impedance circuit Z2 采2 , the voltage V that the second insulating material sample T2 bears 样2 Approximately equal to the output voltage V of the high voltage power supply 输出 Further, in the test unit where the Nth insulating material sample Tn is located, the impedance Z of the Nth insulating material sample Tn 样n Much larger than the resistance R of the Nth protection resistor Rn 保n , the resistance value of the Nth protection resistor Rn is R 保n Much larger than the impedance Z of the Nth detection impedance circuit Zn 采n , the voltage V that the Nth insulating material sample Tn withstands 样n Approximately equal to the output voltage V of the high voltage power supply 输出 That is, the output voltage of the high-voltage power supply is basically evenly distributed on each insulating material sample, and the voltage V 保1 、V 保2 and V 保n It is approximately equal to 0, that is, the potential of the low-voltage electrode to the ground is approximately 0; here, the voltage distribution in other non-breakdown electrode systems is similar and will not be elaborated here.

[0059] Further, such as Figure 8 As shown, when the first insulating material sample T1 is broken down, the impedance Z of the first insulating material sample T1 is 样1is approximately equal to 0, and the resistance relationship between the first protection resistor R1 and the first detection impedance circuit Z1 is R 保1 >>Z 采1 At this time, the first insulating material sample T1 that breaks down withstands the voltage V 样1 is approximately equal to 0, and the voltage V on the first protection resistor R1 保1 Approximately equal to V 输出 , the position A between the first insulating material sample T1 and the first protective resistor R1 and the position B at the high voltage end of the second insulating material sample T2 are at the same potential; further, the voltage of the high voltage power supply is basically distributed on the first protective resistor R1, that is, the high voltage electrode and the low voltage electrode in the broken down electrode system are short-circuited and at the same potential, and the potential to the ground is about V 输出 Here, the insulating bracket for installing the low-voltage electrode can achieve ground isolation during breakdown; the high-voltage electrodes in other non-breakdown electrode systems and the high-voltage electrodes in the breakdown electrode system are connected in parallel with equal voltages, and the voltage distributed on the insulating material samples in the non-breakdown electrode system is still V 输出 The voltage V borne by the second protection resistor R2 to the Nth protection resistor Rn is 保2 ……V 保n Both are approximately equal to 0, therefore, the high voltage state of the sample can be maintained, and there is no power outage due to the voltage suddenly dropping to 0, so the withstand voltage breakdown test can continue.

[0060] The multi-sample insulation withstand voltage test system for insulating materials provided by the present invention has the following characteristics: when the insulation material breaks down, the voltage monitoring unit controls the high-voltage relay to disconnect, and isolates the broken-down insulating material from the test circuits of other test units, so as to isolate the test unit with insulation breakdown from the high-voltage withstand voltage breakdown test circuit, thereby avoiding affecting the test work of other non-breakdown samples, and achieving that after any sample is tested and broken down, other non-breakdown samples still maintain a high-voltage state, and the withstand voltage breakdown measurement of other samples is continuously performed without power failure, which not only solves the damage of instantaneous overvoltage to non-breakdown samples, but also reduces the error between the insulation life obtained by the power-on timing after power failure and the single sample continuous test timing, thereby significantly improving the withstand voltage breakdown test efficiency of the insulating material.

[0061] The above serial numbers of this application are only for description and do not represent the advantages and disadvantages of the implementation scenarios. The above disclosure is only a few specific implementation scenarios of this application, but this application is not limited to them, and any changes that can be thought of by technicians in this field should fall within the scope of protection of this application.

Claims

1. A multi-sample insulation withstand voltage test system for insulating materials, characterized in that: The system includes a protection inductor and a plurality of test units connected in parallel; The first end of the protection inductor is used to connect to an external high-voltage power supply to obtain a test voltage and provide instantaneous current protection for each test unit; The test unit includes a high voltage relay, a high voltage electrode, a low voltage electrode, a protection resistor, a detection impedance circuit, a voltage monitoring unit and an insulating bracket; The first connection end of the high-voltage relay is connected to the second end of the protection inductor to obtain a test voltage; The high-voltage electrode is connected to the second connection end of the high-voltage relay, and an insulating material to be tested is arranged between the low-voltage electrode and the high-voltage electrode; The protection resistor is connected in series between the low voltage electrode and the high voltage end of the detection impedance circuit to protect the test unit from overvoltage, and the low voltage end of the detection impedance circuit is grounded; The voltage acquisition terminal of the voltage monitoring unit is arranged at the high voltage terminal of the detection impedance circuit to monitor the voltage value of the high voltage terminal voltage of the high voltage terminal; The circuit control end of the voltage monitoring unit is connected to the controlled end of the high-voltage relay, so that when the voltage value of the high-voltage terminal voltage is greater than or equal to the preset judgment voltage value, the high-voltage relay is in an off state, so as to isolate the test unit where the high-voltage relay is located from the system; The low-voltage electrode is arranged on the outside of the insulating bracket, and the protective resistor and the detection impedance circuit are arranged inside the insulating bracket, so that the low-voltage electrode, the protective resistor and the detection impedance circuit are fixed in the test unit through the insulating bracket, so that the voltage between the low-voltage electrode, the protective resistor and the detection impedance circuit and the grounding point of the system is isolated.

2. The system according to claim 1, characterized in that The detection impedance circuit includes a diode, a capacitor, a fixed resistor and a variable resistor; The connection end after the cathode end of the diode, the first end of the capacitor, the first end of the fixed resistor and the first end of the variable resistor are connected in parallel is connected to the protection resistor as the high voltage end of the detection impedance circuit; The connection end after the positive terminal of the diode, the second end of the capacitor, the second end of the fixed resistor and the second end of the variable resistor are connected in parallel is grounded as the low voltage end of the detection impedance circuit.

3. The system according to claim 1, characterized in that The voltage monitoring unit includes a voltage comparator, a trigger and a solid-state relay; The first access terminal of the voltage comparator is connected to the high-voltage terminal of the detection impedance circuit to collect the voltage value of the high-voltage terminal voltage, the second access terminal of the voltage comparator is used to access the preset judgment voltage value, and the output terminal of the voltage comparator sends a high-level pulse signal when the voltage value of the high-voltage terminal voltage is greater than or equal to the preset judgment voltage value; The access end of the trigger is connected to the output end of the voltage comparator, the control output end of the trigger is connected to the access end of the solid-state relay, and when the trigger obtains the high-level pulse signal, the signal output end of the trigger sends a breakdown trigger signal and sends a switch disconnection signal to the solid-state relay; The switch control end of the solid-state relay is connected to the controlled end of the high-voltage relay so that the high-voltage relay is in an off state when the switch off signal is received.

4. The system according to claim 3, characterized in that The voltage monitoring unit also includes a photoelectric isolator; The first end of the photoelectric isolator is connected to the high voltage end of the detection impedance circuit, and the second end of the photoelectric isolator is connected to the first access end of the voltage comparator to establish electrical isolation between the detection impedance circuit and the voltage comparator.

5. The system according to claim 3, characterized in that The system also includes a high voltage power supply; The power output terminal of the high-voltage power supply is connected to the first end of the protection inductor to supply power to each of the test units through the protection inductor.

6. The system according to claim 5, characterized in that The system also includes a controller; The controller is connected to the voltage monitoring unit and the high-voltage power supply to obtain the breakdown trigger signal and control the working state of the high-voltage power supply.

7. The system according to claim 6, characterized in that The system also includes an audible and visual alarm unit; The sound and light alarm unit is connected to the controller; The controller is configured to perform the following processes: Real-time monitoring of whether the test unit sends out the breakdown trigger signal; When the test unit sends the breakdown trigger signal, an acoustic and visual prompt message including identification information of the test unit is sent.

8. The system according to claim 6, characterized in that The controller is configured to perform the following processes: In response to the received breakdown trigger signal, determining the test unit that issues the breakdown trigger signal; Determining the length of time from when the high-voltage power supply starts to emit a test voltage to when a breakdown trigger signal emitted by the test unit is received; The length of time is determined as the insulation life time of the insulation material in the test unit.

9. The system according to claim 5, characterized in that The system also includes a remote communication module; The remote communication module is connected to the controller and is used to establish a communication connection between the controller and a remote host computer.

10. The system according to claim 9, characterized in that The remote communication module establishes a communication connection with the host computer via a cellular network.

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