Core grounding current on-line monitoring device external excitation on-site inspection equipment and method

Abstract

The invention discloses an iron core grounding current on-line monitoring device external excitation field inspection device and method, and relates to the related technical field of on-line monitoring devices, and the device comprises a detected iron core grounding current sensor which is used for sensing and reading a current excitation signal, and transmitting the data to an iron core grounding current on-line monitoring device; the iron core grounding current online monitoring device is connected with the detected iron core grounding current sensor and is used for recording a response current detection value of the detected iron core grounding current sensor; the standard sensor is used for sensing and reading a current excitation signal and transmitting data to the inspection host; the external current loop passes through the detected iron core grounding current sensor and the standard sensor, is connected with the detection host and is used for transmitting a current excitation signal; and the inspection host is respectively connected with the standard sensor and an external current loop, and is used for generating and receiving the current excitation signal and recording a response current detection value of the standard sensor at the same time.

Description

Technical Field

[0001] The present application relates to the technical field related to online monitoring devices, and in particular to the field of on-site inspection of core grounding current on-line monitoring devices, and more particularly to an external excitation on-site inspection device and method for core grounding current on-line monitoring devices. Background Art

[0002] At present, a large number of transformers in the power system are equipped with core grounding current online monitoring devices. By monitoring the trend of the core grounding current, it is determined whether there are faults such as multi-point grounding inside the transformer. Therefore, the reliability and accuracy of the core grounding current online monitoring device is crucial.

[0003] However, since the core grounding current online monitoring device is affected by the quality of the manufacturer's installation and commissioning, as well as the long-term complex operating environment, the grounding current performance may gradually deteriorate. Therefore, it is necessary to conduct regular on-site performance inspections of the core grounding current online monitoring device after installation and commissioning. At the same time, the on-site inspection should also consider a restriction, that is, the core grounding current sensor being inspected should not be dismantled without authorization, otherwise it will affect the installation and commissioning status of the sensor. Therefore, this application proposes an external excitation on-site inspection device and method for the core grounding current online monitoring device. Summary of the invention

[0004] The purpose of the embodiment of the present invention is to provide an external excitation field inspection device and method for an online monitoring device for core grounding current, and to judge the operating performance of the online monitoring device for core grounding current by analyzing and comparing the response current and response curve generated by a standard sensor and a core grounding current sensor under test.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] The embodiment of the present invention provides an external excitation field inspection device for an online monitoring device for core grounding current, comprising:

[0007] The core grounding current sensor to be tested is used to sense and read the current excitation signal and transmit the data to the core grounding current online monitoring device;

[0008] An on-line monitoring device for core grounding current, connected to the core grounding current sensor to be tested, and used to record the response current detection value of the core grounding current sensor to be tested;

[0009] Standard sensor, used to sense and read the current excitation signal and transmit the data to the inspection host;

[0010] An external current loop passes through the tested core grounding current sensor and the standard sensor and is connected to the testing host for transmitting a current excitation signal;

[0011] The inspection host is connected to the standard sensor and the external current loop respectively, and is used to generate and receive a current excitation signal, and simultaneously record a response current detection value of the standard sensor.

[0012] In some embodiments, the standard sensor and the tested core grounding current sensor are both semi-enclosed high-precision current transformers.

[0013] In some embodiments, the standard sensor and the detected core grounding current sensor are both arranged outside the transformer core grounding down conductor.

[0014] In some embodiments, the inspection host internally includes:

[0015] A current signal excitation module, used to generate and receive a current excitation signal to the external current loop;

[0016] A current signal testing module, used for recording the response current detection value of the standard sensor;

[0017] Communication module, used for communication connection with external equipment;

[0018] The power supply module is used to supply power to the entire inspection host.

[0019] In some embodiments, the current signal excitation module is a constant current source and can output a constant current of any magnitude between 2mA and 12A.

[0020] In some embodiments, the inspection host also includes a touch display screen for operators to operate and read information at the same time.

[0021] In some embodiments, the external current loop is a signal line, one end of the signal line is connected to the output end of the inspection host as a current emitting end, and the other end of the signal line is connected to the input end of the inspection host as a current returning end.

[0022] In some embodiments, the external current loop includes a red signal line and a black signal line, wherein the red signal line is a current emitting end and the black signal line is a current returning end;

[0023] One end of the red signal line and the black signal line is a Q9 terminal for connecting to the inspection host, and the other end is an alligator wire clamp for fastening and clamping on the transformer core grounding lead.

[0024] Some embodiments of the present invention further provide an external excitation field inspection method for an online monitoring device for core grounding current, using the field inspection device as described above; the field inspection method comprises:

[0025] The test host generates a current excitation signal and outputs it to an external current loop;

[0026] The external current loop transmits the current excitation signal and then inputs it back to the inspection host;

[0027] The standard sensor senses and reads the current excitation signal, and the test host records the response current detection value of the standard sensor;

[0028] The core grounding current sensor under test senses and reads the current excitation signal, and the core grounding current online monitoring device records the response current detection value of the core grounding current sensor under test;

[0029] Compare and analyze the response current detection values ​​of the standard sensor and the tested core grounding current sensor to determine the monitoring accuracy of the core grounding current online monitoring device.

[0030] The core of a normally operating transformer is grounded at a single point. If two or more points are grounded at the same time, a current loop will be formed between the core and the earth. The maximum current can reach tens of amperes, which will cause the core to overheat or even burn. Therefore, the current of the transformer grounding wire needs to be monitored and controlled in real time. At present, there are three problems in the detection methods for judging whether there are multiple points of grounding in the transformer core and the handling methods for current overlimit: First, the existing online monitoring system has few monitoring and current limiting paths, resulting in incomplete hidden danger inspection and high installation cost of the detection system; second, the current acquisition function in the existing transformer core grounding current monitoring system cannot take into account both large range and high precision; third, the existing online monitoring system needs to open the transformer core grounding wire during installation, which makes the installation process complicated and introduces influence on the transformer.

[0031] (1) In most cases, the core and clamps of transformers of 220kV and above are grounded separately, and there is insulation between them. The core and clamps of transformers below 220kV share a common grounding bar. Existing transformer core grounding current monitoring systems only monitor the core grounding current, and do not monitor the clamp grounding current, or require the installation of two monitoring systems next to the transformer, which does not fully detect hidden dangers or increases the system installation cost. In addition, most existing monitoring systems can only measure current and alarm for over-limit situations, but cannot handle current over-limit situations, which require manual processing, resulting in untimely fault handling.

[0032] (2) When the transformer is in normal condition, the grounding current of the core and the clamp is generally below 100mA. When multiple points of grounding occur, the grounding current will exceed 100mA, and may reach 4A or 5A, and may reach 10A or 20A in some cases. The conventional live measurement range is 1mA to 10A. If the grounding current exceeds 10A, the test result will become unreliable, and it is impossible to take into account both the large range and high precision.

[0033] (3) The grounding current of the transformer core and clamps is generally led out from the top of the transformer through an insulating sleeve through an insulated cable or a grounding flat iron, extending along the transformer casing to the bottom of the transformer, and directly grounded at a single point. The diameter of the insulated cable is generally 20mm, and the maximum size of the grounding flat iron is 10mm×80mm. The current transformer in the existing transformer core grounding current monitoring device cannot meet the large size requirements of most grounding flat irons. During the installation of the existing monitoring device, it is necessary to dismantle the grounding wire to be tested and directly connect the device in series with the grounding wire. The installation process is complicated and introduces an impact on the transformer. Once the monitoring device fails, it may cause dangers such as an open circuit in the grounding wire.

[0034] The working principle of the present invention is described in detail below.

[0035] Example 1

[0036] Before the on-site inspection begins, place the standard sensor, external current loop and inspection host as follows: Figure 1 The standard sensor is connected to the position shown, and the standard sensor is fixed on one side of the iron core grounding current sensor under test, and the external current loop is passed through the standard sensor and the iron core grounding current sensor under test, so that the standard sensor and the iron core grounding current sensor under test are capable of detecting the external current excitation signal at the same time.

[0037] When the operator operates the inspection host to apply a series of different current excitation signals and transmits them through the external current loop, the standard sensor and the inspected core grounding current sensor simultaneously sense the current excitation signals and read the current excitation signals flowing through the external current loop, and then record the response current detection values ​​of the standard sensor and the inspected core grounding current sensor respectively. The response current detection value of the standard sensor is recorded by the inspection host, and the response current detection value of the inspected core grounding current sensor is recorded by the core grounding current online monitoring device. The two are compared and analyzed to determine the accuracy of the monitoring of the core grounding current online monitoring device.

[0038] The test host is equipped with a touch screen to facilitate operators to set current excitation signals of different amplitudes. The current excitation signal is then transmitted through an external current loop, so that the standard sensor and the core grounding current sensor under test respond at the same time. After the standard sensor senses the current excitation signal, the response signal is processed by the current signal test module, and the specific response value is displayed on the touch screen of the test host. At the same time, after the core grounding current sensor under test senses the current excitation signal, the specific response value is displayed on the core grounding current online monitoring device. At this time, the operator observes and records the background response value of the core grounding current sensor under test, and compares the background response value with the response value of the standard sensor for curve analysis (including curve linear characteristics, amplitude, etc.), so as to achieve the purpose of judging the channel performance status of the core grounding current sensor under test, thereby judging the accuracy of the core grounding current online monitoring device.

[0039] Example 2

[0040] Before the on-site inspection begins, press the Q9 terminal at one end of the external current loop as shown below. Figure 2 The position shown is connected to the inspection host, the red crocodile wire clamp of the external current loop is fixed to the exposed metal part near the upper end of the transformer core grounding down lead, the black crocodile wire clamp of the external current loop is fixed to the exposed metal part near the lower end of the transformer core grounding down lead, the inspected core grounding current sensor is located between the two wire clamp positions, and the standard sensor is fixed on one side of the inspected core grounding current sensor, also located between the two wire clamp positions, so that the standard sensor and the inspected core grounding current sensor are simultaneously capable of detecting the external current excitation signal.

[0041] When the operator operates the inspection host to apply a series of different current excitation signals, and after transmitting through the external current loop and the transformer core grounding down lead, the standard sensor and the inspected core grounding current sensor simultaneously receive the current excitation signal and read the current excitation signal flowing through the transformer core grounding down lead, and then record the response current detection values ​​of the standard sensor and the inspected core grounding current sensor respectively. The response current detection value of the standard sensor is recorded by the inspection host, and the response current detection value of the inspected core grounding current sensor is recorded by the core grounding current online monitoring device. The two are compared and analyzed to determine the accuracy of the core grounding current online monitoring device.

[0042] The test host is equipped with a touch screen to facilitate operators to set current excitation signals of different amplitudes. The current excitation signal is then transmitted through the external current loop and the transformer core grounding lead, so that the standard sensor and the core grounding current sensor under test respond at the same time. After receiving the current excitation signal, the standard sensor processes the response signal through the current signal test module and displays the specific response value on the touch screen of the test host. At the same time, after receiving the current excitation signal, the core grounding current sensor under test displays the specific response value on the core grounding current online monitoring device. At this time, the operator observes and records the background response value of the core grounding current sensor under test, and compares the background response value with the response value of the standard sensor for curve analysis (including curve linear characteristics, amplitude, etc.), so as to achieve the purpose of judging the channel performance status of the core grounding current sensor under test, thereby judging the accuracy of the core grounding current online monitoring device.

[0043] Generally speaking, the problems of core grounding current online monitoring devices mainly include abnormal sensor excitation response (such as no response with excitation changes, abnormal response indication), wrong sensor background number, no background spectrum, signal communication interruption, etc. The main reasons for the above problems include sensor hardware defects, sensor installation defects, improper background debugging (commonly reversed core and clamp monitoring information, improper sensor gain parameter settings, background spectrum function not enabled), background board failure, signal communication interruption, etc.

[0044] The present invention provides an external excitation field inspection device and method for an iron core grounding current online monitoring device. The iron core grounding current online monitoring device is used on site, and a series of external current excitations are injected through the cores of a standard sensor and an iron core grounding current sensor to be tested through an external current loop. The standard sensor and the iron core grounding current sensor to be tested generate response currents by current induction, and the operating performance of the iron core grounding current online monitoring device is evaluated by analyzing and comparing the response curves of the two.

[0045] The present invention provides an external excitation field inspection device and method for an iron core grounding current online monitoring device, which can complete the field inspection work at any time, safely and quickly under the premise of ensuring that the iron core grounding current sensor to be inspected does not need to be disassembled, so that the field inspection efficiency is high, does not affect the equipment operation, and the field operation safety is high. The present invention is very valuable for promotion.

[0046] Figure 3 This is a curve characteristic diagram of online monitoring of the core grounding current sensor under inspection in good condition. Figure 4-Figure 5It is a schematic diagram of the curve characteristics of the online monitoring abnormality of the inspected core grounding current sensor discovered during on-site inspection. In the figure: the horizontal axis is the inspection host current excitation signal, and the vertical axis is the sensor current response indication. The performance status of the core grounding current online monitoring device is judged by analyzing the change characteristics of the monitoring indication of the inspected core grounding current sensor with the current excitation signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the present disclosure, the following briefly introduces the drawings required for use in some embodiments of the present disclosure. Obviously, the drawings described below are only drawings of some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the products involved in the embodiments of the present disclosure, the actual process of the method, etc.

[0048] Figure 1 It is a schematic diagram of the working principle of the on-site inspection device in some embodiments of the present disclosure;

[0049] Figure 2 It is a schematic diagram of the working principle of the on-site inspection equipment in some other embodiments of the present disclosure;

[0050] Figure 3 It is a curve characteristic diagram of online monitoring of the tested core grounding current sensor in good condition;

[0051] Figure 4 A schematic diagram of the curve characteristics of the on-line monitoring of the core grounding current sensor under test with a relatively small response amplitude;

[0052] Figure 5 A schematic diagram of the curve characteristics of the on-line monitoring of the core grounding current sensor under test with a large response amplitude;

[0053] In the figure, the horizontal axis is the current excitation signal of the inspection host, and the vertical axis is the sensor current response indication. DETAILED DESCRIPTION

[0054] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.

[0055] Unless the context requires otherwise, throughout the specification and claims, the term "including" is to be interpreted as an open, inclusive meaning, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "examples" or "some examples" and the like are intended to indicate that specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present disclosure. The schematic representations of the above terms do not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics described may be included in any one or more embodiments or examples in any appropriate manner.

[0056] The embodiment of the present invention provides an external excitation field inspection device for an on-line monitoring device for core grounding current, such as Figure 1 As shown, it includes: a core grounding current sensor to be tested, a core grounding current online monitoring device, a standard sensor, an external current loop and a testing host.

[0057] In some examples, the core grounding current sensor under inspection is used to sense and read the current excitation signal and transmit the data to the core grounding current online monitoring device.

[0058] In some examples, the core grounding current online monitoring device is connected to the core grounding current sensor to be tested, and is used to record the response current detection value of the core grounding current sensor to be tested. When the core grounding current sensor to be tested senses the current excitation signal, the data is transmitted to the core grounding current online monitoring device, and the core grounding current online monitoring device displays the specific response value, so as to facilitate the subsequent judgment of the accuracy of the core grounding current online monitoring device.

[0059] In some examples, standard sensors are used to sense and read the current excitation signal and transmit the data to a test host.

[0060] In some examples, the external current loop passes through the core grounding current sensor under test and the standard sensor, and is connected to the inspection host for transmitting the current excitation signal.

[0061] For example, Figure 1 As shown, the external current loop is a signal line, one end of which is connected to the output end of the test host as the current sending end, and the other end of the signal line is connected to the input end of the test host as the current return end. At the same time, the external current loop passes through the center of the tested core grounding current sensor and the standard sensor. When the test host outputs the current excitation signal through the output end, it is transmitted through the external current loop and input back to the input end of the test host.

[0062] For example, Figure 2As shown, the external current loop includes a red signal line and a black signal line, wherein the red signal line is the current emitting end and the black signal line is the current returning end; one end of the red signal line and the black signal line is a Q9 terminal for connecting the inspection host, and the other end is an alligator wire clip for fastening and clamping on the transformer core grounding lead. At the same time, the external current loop is set on the outside of the inspected core grounding current sensor and the standard sensor, that is, the inspected core grounding current sensor and the standard sensor are set between the red signal line and the black signal line of the external current loop. When the inspection host outputs the current excitation signal through the output end, it is transmitted through the external current loop and the transformer core grounding lead, and then input back to the input end of the inspection host.

[0063] In some examples, the test host is connected to the standard sensor and the external current loop, respectively, to generate and receive the current excitation signal, and record the response current detection value of the standard sensor. The test host is connected to the standard sensor, and when the standard sensor senses the current excitation signal, the data is transmitted to the test host, and the test host displays the specific response value to facilitate the subsequent judgment of the accuracy of the core grounding current online monitoring device. The test host is connected to the external current loop, outputting different current excitation signals to the external current loop while receiving the current excitation signal input back from the external current loop.

[0064] The present invention provides an external excitation field inspection device for an iron core grounding current online monitoring device. The iron core grounding current online monitoring device is used on site, and a series of external current excitations are injected through the cores of a standard sensor and an iron core grounding current sensor to be tested through an external current loop. The standard sensor and the iron core grounding current sensor to be tested generate response currents by current induction, and the operating performance of the iron core grounding current online monitoring device is evaluated by analyzing and comparing the response curves of the two.

[0065] In some examples, the standard sensor and the core grounding current sensor to be tested are both semi-enclosed high-precision current transformers, and the specific model may be any one of LMZC-10PU, LZCT-10C, LMZK5-10, LMZK1-10, LMZK2-10, LMZK3-10, LMZK4-10, LMZK5-10, LMZK6-10, and LMZK10-10.

[0066] In some examples, the standard sensor and the core grounding current sensor to be tested are both arranged outside the transformer core grounding down conductor.

[0067] In some examples, the inspection host internally includes a current signal excitation module, a current signal inspection module, a communication module, and a power supply module.

[0068] Exemplarily, the current signal excitation module is used to generate and receive a current excitation signal to an external current loop; the current signal inspection module is used to record the response current detection value of the standard sensor; the communication module is used to communicate with external devices; and the power supply module is used to supply power to the entire inspection host.

[0069] Exemplarily, the current signal excitation module is a constant current source and can output a constant current of any magnitude between 2 mA and 12 A. The operator can operate the inspection host to output current excitation signals of different values ​​through the current signal excitation module, and the accuracy of the output current of the current signal excitation module is no more than ±2%.

[0070] Exemplarily, the inspection host also includes a touch screen for operators to operate and read information at the same time. The operator inputs current excitation signals of different values ​​through the touch screen, and after the standard sensor transmits the sensed current excitation signal to the inspection host, the specific response value is displayed through the touch screen to facilitate the subsequent judgment of the accuracy of the core grounding current online monitoring device.

[0071] The embodiment of the present invention further provides an external excitation field inspection method for an online monitoring device for core grounding current, which adopts the field inspection equipment as described above; the field inspection method includes: S100-S500.

[0072] S100, verify that the host generates a current excitation signal and outputs it to an external current loop.

[0073] S200, the external current loop transmits the current excitation signal, which is then input back to the inspection host.

[0074] S300, the standard sensor senses and reads the current excitation signal, and the test host records the response current detection value of the standard sensor.

[0075] S400, the core grounding current sensor under test senses and reads the current excitation signal, and the core grounding current online monitoring device records the response current detection value of the core grounding current sensor under test.

[0076] S500, comparing and analyzing the response current detection values ​​of the standard sensor and the core grounding current sensor under test, and judging the monitoring accuracy of the core grounding current online monitoring device.

[0077] The working principle of the present invention is described in detail below.

[0078] Example 1

[0079] Before the on-site inspection begins, place the standard sensor, external current loop and inspection host as follows: Figure 1The standard sensor is connected to the position shown, and the standard sensor is fixed on one side of the iron core grounding current sensor under test, and the external current loop is passed through the standard sensor and the iron core grounding current sensor under test, so that the standard sensor and the iron core grounding current sensor under test are capable of detecting the external current excitation signal at the same time.

[0080] When the operator operates the inspection host to apply a series of different current excitation signals and transmits them through the external current loop, the standard sensor and the inspected core grounding current sensor simultaneously sense the current excitation signals and read the current excitation signals flowing through the external current loop, and then record the response current detection values ​​of the standard sensor and the inspected core grounding current sensor respectively. The response current detection value of the standard sensor is recorded by the inspection host, and the response current detection value of the inspected core grounding current sensor is recorded by the core grounding current online monitoring device. The two are compared and analyzed to determine the accuracy of the monitoring of the core grounding current online monitoring device.

[0081] The test host is equipped with a touch screen to facilitate operators to set current excitation signals of different amplitudes. The current excitation signal is then transmitted through an external current loop, so that the standard sensor and the core grounding current sensor under test respond at the same time. After the standard sensor senses the current excitation signal, the response signal is processed by the current signal test module, and the specific response value is displayed on the touch screen of the test host. At the same time, after the core grounding current sensor under test senses the current excitation signal, the specific response value is displayed on the core grounding current online monitoring device. At this time, the operator observes and records the background response value of the core grounding current sensor under test, and compares the background response value with the response value of the standard sensor for curve analysis (including curve linear characteristics, amplitude, etc.), so as to achieve the purpose of judging the channel performance status of the core grounding current sensor under test, thereby judging the accuracy of the core grounding current online monitoring device.

[0082] Example 2

[0083] Before the on-site inspection begins, press the Q9 terminal at one end of the external current loop as shown below. Figure 2 The position shown is connected to the inspection host, the red crocodile wire clamp of the external current loop is fixed to the exposed metal part near the upper end of the transformer core grounding down lead, the black crocodile wire clamp of the external current loop is fixed to the exposed metal part near the lower end of the transformer core grounding down lead, the inspected core grounding current sensor is located between the two wire clamp positions, and the standard sensor is fixed on one side of the inspected core grounding current sensor, also located between the two wire clamp positions, so that the standard sensor and the inspected core grounding current sensor are simultaneously capable of detecting the external current excitation signal.

[0084] When the operator operates the inspection host to apply a series of different current excitation signals, and after transmitting through the external current loop and the transformer core grounding down lead, the standard sensor and the inspected core grounding current sensor simultaneously receive the current excitation signal and read the current excitation signal flowing through the transformer core grounding down lead, and then record the response current detection values ​​of the standard sensor and the inspected core grounding current sensor respectively. The response current detection value of the standard sensor is recorded by the inspection host, and the response current detection value of the inspected core grounding current sensor is recorded by the core grounding current online monitoring device. The two are compared and analyzed to determine the accuracy of the core grounding current online monitoring device.

[0085] The test host is equipped with a touch screen to facilitate operators to set current excitation signals of different amplitudes. The current excitation signal is then transmitted through the external current loop and the transformer core grounding lead, so that the standard sensor and the core grounding current sensor under test respond at the same time. After receiving the current excitation signal, the standard sensor processes the response signal through the current signal test module and displays the specific response value on the touch screen of the test host. At the same time, after receiving the current excitation signal, the core grounding current sensor under test displays the specific response value on the core grounding current online monitoring device. At this time, the operator observes and records the background response value of the core grounding current sensor under test, and compares the background response value with the response value of the standard sensor for curve analysis (including curve linear characteristics, amplitude, etc.), so as to achieve the purpose of judging the channel performance status of the core grounding current sensor under test, thereby judging the accuracy of the core grounding current online monitoring device.

[0086] Generally speaking, the problems of core grounding current online monitoring devices mainly include abnormal sensor excitation response (such as no response with excitation changes, abnormal response indication), wrong sensor background number, no background spectrum, signal communication interruption, etc. The main reasons for the above problems include sensor hardware defects, sensor installation defects, improper background debugging (commonly reversed core and clamp monitoring information, improper sensor gain parameter settings, background spectrum function not enabled), background board failure, signal communication interruption, etc.

[0087] The present invention provides an external excitation field inspection device and method for an iron core grounding current online monitoring device. The iron core grounding current online monitoring device is used on site, and a series of external current excitations are injected through the cores of a standard sensor and an iron core grounding current sensor to be tested through an external current loop. The standard sensor and the iron core grounding current sensor to be tested generate response currents by current induction, and the operating performance of the iron core grounding current online monitoring device is evaluated by analyzing and comparing the response curves of the two.

[0088] The present invention provides an external excitation field inspection device and method for an iron core grounding current online monitoring device, which can complete the field inspection work at any time, safely and quickly under the premise of ensuring that the iron core grounding current sensor to be inspected does not need to be disassembled, so that the field inspection efficiency is high, does not affect the equipment operation, and the field operation safety is high. The present invention is very valuable for promotion.

[0089] Figure 3 This is a curve characteristic diagram of online monitoring of the core grounding current sensor under inspection in good condition. Figure 4-Figure 5 It is a schematic diagram of the curve characteristics of the online monitoring abnormality of the inspected core grounding current sensor discovered during on-site inspection. In the figure: the horizontal axis is the inspection host current excitation signal, and the vertical axis is the sensor current response indication. The performance status of the core grounding current online monitoring device is judged by analyzing the change characteristics of the monitoring indication of the inspected core grounding current sensor with the current excitation signal.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. An external excitation field inspection device for an online monitoring device for core grounding current, characterized in that: include: The core grounding current sensor to be tested is used to sense and read the current excitation signal and transmit the data to the core grounding current online monitoring device; An iron core grounding current online monitoring device, connected to the iron core grounding current sensor to be tested, and used to record the response current detection value of the iron core grounding current sensor to be tested; A standard sensor is used to sense and read the current excitation signal and transmit the data to the inspection host; an external current loop passes through the inspected core grounding current sensor and the standard sensor and is connected to the inspection host to transmit the current excitation signal; The inspection host is connected to the standard sensor and the external current loop respectively, and is used to generate and receive a current excitation signal, and simultaneously record a response current detection value of the standard sensor.

2. The external excitation field inspection equipment for core grounding current online monitoring device according to claim 1, characterized in that: The standard sensor and the tested core grounding current sensor are both semi-enclosed high-precision current transformers.

3. The external excitation field inspection equipment for core grounding current online monitoring device according to claim 1, characterized in that: The standard sensor and the detected core grounding current sensor are both arranged outside the transformer core grounding down conductor.

4. The external excitation field inspection equipment for core grounding current online monitoring device according to claim 1, characterized in that: The inspection host internally includes: A current signal excitation module, used to generate and receive a current excitation signal to the external current loop; A current signal testing module, used for recording the response current detection value of the standard sensor; Communication module, used for communication connection with external equipment; The power module is used to supply power to the entire inspection host.

5. The external excitation field inspection equipment for core grounding current online monitoring device according to claim 4, characterized in that: The current signal excitation module is a constant current source and can output a constant current of any size between 2mA and 12A.

6. The external excitation field inspection equipment for core grounding current online monitoring device according to claim 4, characterized in that: The inspection host also includes a touch display screen for operators to operate and read information at the same time.

7. The external excitation field inspection equipment for core grounding current online monitoring device according to claim 1, characterized in that: The external current loop is a signal line, one end of which is connected to the output end of the inspection host as a current emitting end, and the other end of which is connected to the input end of the inspection host as a current returning end.

8. The external excitation field inspection equipment for core grounding current online monitoring device according to claim 1, characterized in that: The external current loop includes a red signal line and a black signal line, wherein the red signal line is a current emitting end and the black signal line is a current returning end; One end of the red signal line and the black signal line is a Q9 terminal for connecting to the inspection host, and the other end is an alligator wire clamp for fastening and clamping on the transformer core grounding lead.

9. A method for external excitation field inspection of an online monitoring device for core grounding current, characterized in that: Using the on-site inspection equipment as described in any one of claims 1 to 8; The on-site inspection method comprises: The test host generates a current excitation signal and outputs it to an external current loop; The external current loop transmits the current excitation signal and then inputs it back to the inspection host; The standard sensor senses and reads the current excitation signal, and the test host records the response current detection value of the standard sensor; The core grounding current sensor under test senses and reads the current excitation signal, and the core grounding current online monitoring device records the response current detection value of the core grounding current sensor under test; the response current detection values ​​of the standard sensor and the core grounding current sensor under test are compared and analyzed to determine the accuracy of the monitoring of the core grounding current online monitoring device.

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