Electric heater insulation resistance on-line detection equipment and detection device

Abstract

The utility model provides an electric heater insulation resistance on-line detection device and a detection device, the detection device comprises an isolation module, N electric heating element units and an insulation detector, an external network power supply provides working voltage for each electric heating element unit and the insulation detector through the isolation module, the insulation detector is arranged between the isolation module and the electric heating element units, and performs resistance value detection on the electric heating element units in a heating state to obtain insulation resistance values, so that on-line detection of insulation resistance is realized, and insulation resistance detection of N electric heating element units can be obtained at the same time; the method is high in detection efficiency, accurate in detection result, safe, reliable and wide in application range.

Description

Technical Field

[0001] The utility model relates to the field of electronic circuit detection, and particularly relates to an on-line detection device and a detection apparatus for the insulation resistance of an electric heater. Background Art

[0002] The main function of an electric heating element is to heat the reactor coolant during the rated conditions and variable load operation of a pressurized water reactor, so as to maintain it at the saturation temperature that meets the operating pressure, thereby controlling and regulating the pressure fluctuation of the reactor coolant system. The electric heating element plays a key role in the normal operation of the reactor. An important performance index of the electric heating element is the insulation resistance value. In the related art, for the measurement of the insulation resistance of an electric heater product, usually the cold-state insulation resistance is measured, or after the electric heating element is fully heated, the power supply circuit is cut off, and the insulation resistance value at the high-temperature state is measured. The insulation resistance of an electric heater product will be greatly reduced during the operation state. The traditional cold-state insulation resistance and high-temperature insulation resistance cannot timely reflect the insulation condition of the heater during the operation state, the test efficiency is low and the test result is inaccurate, and the insulation breakdown fault during the heating process of the electric heating element cannot be monitored, there are certain potential safety hazards.

[0003] Therefore, how to provide a detection device that can detect the insulation resistance value of an electric heating element in real time is a technical problem that needs to be solved urgently at present. Summary of the Utility Model

[0004] In view of the above-mentioned disadvantages of the prior art, the utility model provides an on-line detection device and a detection apparatus for the insulation resistance of an electric heater to solve at least one of the above technical problems.

[0005] To achieve the above object and other related objects, the technical solutions provided in this application are as follows.

[0006] On the one hand, this application provides an on-line detection device for the insulation resistance of an electric heater, including an isolation module, N electric heating element units and an insulation detector. The input end of the isolation module is connected to an external network power supply, the output end of the isolation module is connected to the electric heating element unit, N electric heating element units are arranged in parallel, the power supply end of the insulation detector is connected to the output end of the isolation module, the grounding end of the insulation detector is connected to the shell of the electric heating element in the electric heating element unit and grounded. The insulation detector is used to detect the resistance value of the electric heating element in the heating state based on the measurement signal to obtain the insulation resistance value, where N is a positive integer.

[0007] In an embodiment of the utility model, the detection device further includes a temperature sensor and a controller. The temperature sensor is arranged on the shell of the electric heating element, and the temperature sensor is connected to the controller.

[0008] In an embodiment of the present utility model, the controller includes a collection unit, an interface unit, a data processing unit, and a PLC control unit. The input end of the collection unit is connected to the electric heating element and the insulation detector, the output end of the collection unit is connected to the interface unit and the data processing unit, the input end of the data processing unit is further connected to the interface unit, the output end of the data processing unit is connected to the PLC control unit, and the output end of the PLC control unit is connected to the electric heating element unit.

[0009] In an embodiment of the present utility model, the interface unit is further connected to the electric heating element unit.

[0010] In an embodiment of the present utility model, the isolation module includes a transformer, a first relay, and a second relay. The first end of the primary coil of the transformer is connected to the positive pole of the external network power supply through the first relay, the second end of the primary coil of the transformer is connected to the negative pole of the external network power supply through the second relay, and the secondary coil of the transformer outputs a working voltage.

[0011] In an embodiment of the present utility model, the electric heating element unit includes a first contactor, a second contactor, and the electric heating element. The first end of the first contactor is connected to the first end of the electric heating element, the second end of the electric heating element is connected to the first end of the second contactor, and the second ends of the first contactor and the second contactor cooperate to input the working voltage.

[0012] On the other hand, the present application provides a detection device, including the on-line detection equipment for the insulation resistance of the electric heater as described above, to detect the insulation resistance of the electric heater.

[0013] The present application provides an on-line detection equipment and a detection device for the insulation resistance of an electric heater. The detection equipment includes an isolation module, N electric heating element units, and an insulation detector. The external network power supply provides a working voltage to each electric heating element unit and the insulation detector through the isolation module. The insulation detector is arranged between the isolation module and the electric heating element unit, and detects the resistance value of the electric heating element unit in the heating state to obtain the insulation resistance value, realizing the on-line detection of the insulation resistance, and can simultaneously obtain the insulation resistance detection of N electric heating element units, with high detection efficiency, accurate, safe and reliable detection results, and wide application range.

[0014] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present utility model, and are used together with the specification to explain the principles of the present utility model. Obviously, the accompanying drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, other accompanying drawings can be obtained based on these drawings without creative efforts. In the accompanying drawings:

[0016] Figure 1 is a block diagram of an on-line detection device for the insulation resistance of an electric heater shown in an exemplary embodiment of the present utility model;

[0017] Figure 2 is a page schematic diagram of an interface unit shown in an exemplary embodiment of the present utility model;

[0018] Figure 3 is a specific structural diagram of an on-line detection device for the insulation resistance of an electric heater shown in an exemplary embodiment of the present utility model. Detailed implementation manners

[0019] The following will describe the implementation manners of the present utility model with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification. The present utility model can also be implemented or applied through other different specific implementation manners. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present utility model. It should be understood that the preferred embodiments are only for explaining the present utility model and not for limiting the protection scope of the present utility model.

[0020] It should be noted that the illustrations provided in the following embodiments only schematically show the basic concept of the present utility model. Therefore, only the components related to the present utility model are shown in the drawings, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and proportion of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0021] In the following description, a large number of details are explored to provide a more thorough explanation of the embodiments of the present utility model. However, it is obvious to those skilled in the art that the embodiments of the present utility model can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present utility model difficult to understand.

[0022] Online insulation monitoring technology is mainly applied to IT power supply systems such as rail transit, petrochemical industry, ships and vessels. When a single-phase grounding fault occurs for the first time or the insulation resistance is lower than the specified threshold value in a neutral point non-grounding system, the power supply system can continue to operate, but an insulation monitor should issue an alarm signal. The main methods include: DC component method, DC superposition method, dielectric loss method, partial discharge method, AC superposition method, low-frequency AC injection method, etc.

[0023] An electric heating element is a component that converts electrical energy into heat energy and is the heart of an electric heater. The main function of the electric heating element is to heat the reactor coolant during the rated conditions and variable load operation of a pressurized water reactor, so that it is maintained at the saturated temperature that meets the operating pressure, thereby controlling and regulating the pressure fluctuation of the reactor coolant system. The electric heating element plays a key role in the normal operation of the reactor. An important performance index of the electric heating element is the insulation resistance value. In related technologies, the insulation resistance measurement of electric heater products usually measures its cold-state insulation resistance, or cuts off the power circuit after the electric heating element is fully heated, and measures its insulation resistance value at high temperature. The insulation resistance of electric heater products will be greatly reduced during operation. The traditional cold-state insulation resistance and high-temperature insulation resistance cannot timely reflect the insulation condition of the heater during operation, the test efficiency is low and the test results are inaccurate, and the insulation breakdown fault during the heating process of the electric heating element cannot be monitored, there are certain safety hazards.

[0024] As Figure 1 shown, the present application provides an on-line detection device for the insulation resistance of an electric heater, including an isolation module, N electric heating element units and an insulation detector. The input end of the isolation module is connected to the external network power supply V1, the output end of the isolation module is connected to the electric heating element units, and the N electric heating element units are arranged in parallel. The power supply end of the insulation detector is connected to the output end of the isolation module, and the grounding end of the insulation detector is connected to the shell of the electric heating element in the electric heating element unit and grounded. The insulation detector is used to detect the resistance value of the electric heating element in the heating state based on the measurement signal to obtain the insulation resistance value, where N is a positive integer.

[0025] It should be emphasized that the insulation detector can adopt an ISO685 insulation monitor to detect the insulation resistance value by using a superimposed adaptive pulse voltage signal.

[0026] Specifically, the detection device further includes a temperature sensor and a controller. The temperature sensor is arranged on the shell of the electric heating element and is connected to the controller. Specifically, the temperature sensor includes: thermocouple temperature sensor, platinum resistance temperature sensor, fine K-type thermocouple, etc. The temperature sensor is used to sample the temperature of the electric heating element to obtain temperature data. The temperature sensor is connected to the controller, and the controller controls the working state of the electric heating element unit according to the temperature data and the preset temperature data.

[0027] More specifically, the controller includes a collection unit, an interface unit, a data processing unit, and a PLC control unit. The input end of the collection unit is connected to the electric heating element and the insulation detector, and the output end of the collection unit is connected to the interface unit and the data processing unit. The input end of the data processing unit is also connected to the interface unit, and the output end of the data processing unit is connected to the PLC control unit. The output end of the PLC control unit is connected to the electric heating element unit. Specifically, the collection unit can be a multi-channel data collector, which is used to collect the temperature data of the electric heating element and the insulation resistance value detected by the insulation detector. The collection unit sends the temperature data and the insulation resistance value to the interface unit for display. The interface unit can be a human-machine interface (HMI), and the data processing unit can be a data processor. The data processing unit generates a drive signal based on the temperature data and the preset temperature data set by the interface unit. The PLC control unit can be a PLC control cabinet, and the PLC control unit controls the working state of the electric heating element unit based on the drive signal.

[0028] More specifically, the interface unit is also connected to the electric heating element unit. The interface unit also monitors the working state of the electric heating element unit and stores the temperature data and the insulation resistance value of the electric heating element unit according to the preset time frequency for subsequent viewing.

[0029] Among them, the interface unit mainly realizes human-machine interaction, displays the temperature data and the insulation resistance value of each electric heating element on the touch screen, starts, stops, and sets the temperature of each electric heating element loop through the input instructions, and also realizes the real-time monitoring of the working state of the electric heating element unit. As Figure 2 shown, the screen design on the interface unit display realizes all operation and display functions (input and display parameters, storage records, alarms, etc.). The main functions include: (1) Display of status information, such as real-time temperature display, operation status indication, over-temperature alarm display, etc. (2) Recording of historical data such as the temperature of the electric heating element, the number of the electric heating element, and the insulation resistance value; (3) Query of historical alarms; (4) Setting of start-stop temperature parameters; (5) A data memory card is designed to automatically store the parameter data (temperature data, insulation resistance value, number of electric heating elements, etc.) during the operation of the electric heating element. The preset time frequency is set according to the actual needs and the memory of the data memory card.

[0030] Specifically, as Figure 3As shown in the figure, the isolation module includes a transformer T1, a first relay OF1, and a second relay OF2. The first end of the primary coil of the transformer T1 is connected to the positive pole V1+ of the external network power supply through the first relay OF1, and the second end of the primary coil of the transformer T1 is connected to the negative pole V1- of the external network power supply through the second relay OF2. The secondary coil of the transformer T1 outputs a working voltage. Among them, the first relay and the second relay are used to cut off the input of the external network power supply.

[0031] More specifically, the electric heating element unit includes a first contactor, a second contactor, and an electric heating element. The first end of the first contactor is connected to the first end of the electric heating element, the second end of the electric heating element is connected to the first end of the second contactor, and the second ends of the first contactor and the second contactor cooperate to input a working voltage. Specifically, as Figure 3 shown, when there are 8 electric heating element units, the first electric heating element unit includes a first contactor K1, a second contactor K2, and an electric heating element R1. The first end of the first contactor K1 is connected to the first end of the electric heating element R1, the second end of the electric heating element R1 is connected to the first end of the second contactor K2, the second end of the second contactor K2 is connected to the first end of the secondary coil of the transformer T1, the second end of the first contactor K1 is connected to the second end of the secondary coil of the transformer T1, and the second ends of the first contactor K1 and the second contactor K2 cooperate to input a working voltage. The connection relationships of the structures of other electric heating element units are the same as those of the first electric heating element unit and will not be elaborated here.

[0032] It should be emphasized that, as Figure 3 shown, the first input end of the insulation detector is connected to the first end of the secondary coil of the transformer T1, the second input end of the insulation detector is connected to the second end of the secondary coil of the transformer T1, the grounding end of the insulation detector is grounded, and the grounding end of the insulation detector is also connected to the outer shells of each electric heating element to form a detection circuit. Among them, as Figure 3 shown, the dotted line enclosing the electric heating elements (R1~R8) is the outer shell of the electric heating element.

[0033] Combined with Figures 1 - 3 shown, the principle of the on-line insulation resistance detection device for the electric heater provided by this application is as follows:

[0034] The voltage of the external network power supply V1 (380VAC) is isolated and transformed through the isolation module to obtain a working voltage, and the working voltage is transmitted to each electric heating element unit. A temperature sensor is welded to the outer shell of the electric heating element to detect the temperature of the electric heating element. The controller controls the working state of the electric heating element unit according to the temperature data collected by the temperature sensor and the preset temperature data. The status monitoring, data recording and storage, and temperature setting of the electric heating unit are realized through the interface unit.

[0035] Scope of application of the device: single-ended metal tubular element; applicable voltage range: 0 - 690V AC, 0 - 1000V DC; measurement temperature: 335°C, 360°C; measurement accuracy: 1kΩ; measurement range: 0 - 20MΩ; minimum response time: 1s; number of measurements: 8 pieces.

[0036] First, input a start instruction through the interface unit. The start instruction includes a power control signal and a drive signal. The power control signal controls the closing of the first relay QF1 and the second relay QF2. The PLC control unit controls the closing of both the first contactor and the second contactor according to the drive signal, and all the electric heating element units are in the working state. The insulation detector is connected in series in the loop between the transformer T1 and the ground, superimposing a measurement signal (low-frequency alternating current) between the transformer T1 and the ground. The measurement signal and the insulation resistance of the electric heating element unit to the ground form a measurement loop. By analyzing and processing the detected current, the corresponding insulation resistance value can be obtained. This detection method lies in that the measurement signal can automatically adapt and adjust the magnitude of the output signal according to the magnitude of the distributed leakage capacitance of the monitored electric heating element unit and the level of the insulation resistance value of the electric heating element unit, so as to realize the detection of the insulation resistance value.

[0037] Use an insulation resistance tester to detect the insulation resistance of 8 electric heating elements. The experimental data obtained is shown in Table 1:

[0038] Table 1 Experimental data

[0039]

[0040] In addition, separately conduct a temperature test on the surface of the electric heating element numbered R8 and a dry burning test. The online insulation resistance value data of the test is as follows: 560°C: 14MΩ; 600°C: 2.1MΩ; 700°C: 0.7MΩ; 800°C: 0.240MΩ; 900°C: 0.103MΩ.

[0041] The traditional high-temperature insulation test takes about 10 minutes (including wiring, power-on, power-off, measurement, cooling, and wiring removal) to test one electric heating element. The insulation resistance tester provided in this application can test 8 electric heating elements at a time, and the test time is about 16 minutes, improving the test efficiency.

[0042] When the electric heating element is performing real-time heating, the insulation resistance value in its working state is tested by an insulation resistance meter, the real-time temperature of the electric heating element is measured by a temperature sensor, the temperature data and insulation resistance value of the electric heating element are collected by the acquisition unit, and the real-time operation data is sent to the interface unit for real-time display. The preset temperature data is set through the interface unit, and the data processing unit generates a drive signal based on the temperature data and the preset temperature data. When the temperature data is greater than or equal to the preset temperature data, the PLC control unit disconnects the first contactor and the second contactor based on the drive signal to control the electric heating element to stop operating.

[0043] The present application also provides a detection device, including the on-line insulation resistance detection equipment for electric heaters as described above, to detect the insulation resistance of the electric heater.

[0044] The present application provides an on-line insulation resistance detection equipment and a detection device for electric heaters. The detection equipment includes an isolation module, N electric heating element units and an insulation detector. The external network power supply provides working voltage for each electric heating element unit and the insulation detector through the isolation module. The insulation detector is arranged between the isolation module and the electric heating element units and is used for on-line insulation detection of the electric heating element units, filling the blank of on-line insulation resistance measurement equipment. The insulation detector directly outputs the insulation resistance value. Compared with the traditional measurement method, there is no need to replace the wiring and wait for cooling multiple times, reducing the risks of electric shock and high-temperature scalding, and the detection result is more accurate. It can directly detect the insulation resistance of N electric heating element units, improving the detection efficiency. The temperature of the electric heating element is detected by a temperature sensor, and the working state of the electric heating element is controlled in real time according to the temperature data. The detection efficiency is high, the detection result is accurate, safe and reliable, and the applicable range is wide.

[0045] The above embodiments only exemplarily illustrate the principles and effects of the present invention, rather than limiting the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. An online detection device for insulation resistance of an electric heater, characterized in that: It includes an isolation module, N electric heating element units and an insulation tester, wherein the input end of the isolation module is connected to an external power supply, the output end of the isolation module is connected to the electric heating element unit, the N electric heating element units are arranged in parallel, the power supply end of the insulation tester is connected to the output end of the isolation module, the grounding end of the insulation tester is connected to the shell of the electric heating element in the electric heating element unit and is grounded, and the insulation tester is used to detect the resistance value of the electric heating element in the heating state based on the measurement signal to obtain the insulation resistance value, wherein N is a positive integer.

2. The electric heater insulation resistance online detection device according to claim 1 is characterized in that: The detection device also includes a temperature sensor and a controller. The temperature sensor is arranged on the housing of the electric heating element, and the temperature sensor is connected to the controller.

3. The online detection device for insulation resistance of an electric heater according to claim 2, characterized in that: The controller includes a collection unit, an interface unit, a data processing unit, and a PLC control unit. The input end of the collection unit is connected to the electric heating element and the insulation detector, the output end of the collection unit is connected to the interface unit and the data processing unit, the input end of the data processing unit is also connected to the interface unit, the output end of the data processing unit is connected to the PLC control unit, and the output end of the PLC control unit is connected to the electric heating element unit.

4. The online detection device for insulation resistance of an electric heater according to claim 3, characterized in that: The interface unit is also connected to the electric heating element unit.

5. The online detection device for insulation resistance of an electric heater according to claim 1, characterized in that: The isolation module includes a transformer, a first relay, and a second relay. The first end of the primary coil of the transformer is connected to the positive pole of the external power supply via the first relay, and the second end of the primary coil of the transformer is connected to the negative pole of the external power supply via the second relay. The secondary coil of the transformer outputs a working voltage to the outside.

6. The online detection device for insulation resistance of an electric heater according to claim 5, characterized in that: The electric heating element unit includes a first contactor, a second contactor and the electric heating element, the first end of the first contactor is connected to the first end of the electric heating element, the second end of the electric heating element is connected to the first end of the second contactor, and the second end of the first contactor and the second end of the second contactor cooperate to input the working voltage.

7. A detection device, characterized in that: The invention comprises an online detection device for the insulation resistance of an electric heater as claimed in any one of claims 1 to 6, so as to detect the insulation resistance of the electric heater.

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