An on-line monitoring device, system and method for a controllable surge arrester

Abstract

This invention discloses an online monitoring device, system, and method for a controllable surge arrester. The device includes: a current sampling module to collect leakage current from the controllable and switching components; a voltage sampling module to collect system voltage; and a digital signal processing module to calculate various types of current parameters for the controllable surge arrester and switching components based on the system voltage, leakage current of the controllable and switching components, and send these parameters to a monitoring backend. The monitoring backend compares these various current parameters with the electrical life test parameters of the controllable surge arrester throughout its entire lifespan to obtain a health index for the controllable surge arrester. This invention uses the leakage current of the power electronic switch as a characteristic quantity, enabling non-invasive detection. It provides a broad application market for monitoring the status of power electronic switches in enclosed, compact environments with strict leakage current limitations, allowing for the assessment of the electrical lifespan of the power electronic switches and ensuring their safe and reliable operation.

Description

Technical Field

[0001] This invention relates to the field of surge arrester technology, and specifically to an online monitoring device, system and method for a controllable surge arrester. Background Technology

[0002] Power electronic controlled surge arresters possess excellent switching performance, rapid operating characteristics, and flexible control advantages, representing the future technological trend for deep suppression of system switching overvoltages in ultra-high voltage AC transmission systems. The performance of power electronic switches directly affects the reliable operation of controlled surge arresters, thus impacting the safe and stable operation of the power system. Therefore, it is necessary to conduct health status assessments on the power electronic switches of controlled surge arresters to determine the electrical life of the equipment.

[0003] Currently, power electronic equipment often uses the method of directly monitoring the voltage drop across the device to reflect its operating status. However, this method is not suitable for controllable surge arrester power electronic switches, mainly for the following reasons:

[0004] 1) The voltage drop method is a fault diagnosis method, not a fault early warning method. The former aims to locate the fault as early as possible after it occurs, reducing the duration of the fault, while the latter tends to assess the current performance status of the target equipment by monitoring characteristic parameter data, and provide timely warnings when the equipment performance deteriorates, thereby preventing the fault from occurring.

[0005] 2) The voltage drop method requires an auxiliary power supply circuit and a voltage monitoring circuit, which is complicated in wiring and occupies a lot of space. The power electronic switch of the controllable surge arrester is integrated inside the porcelain bushing. The internal space of the porcelain bushing is compact and cannot accommodate the auxiliary power supply and voltage monitoring circuit.

[0006] 3) The voltage drop method is an "intrusive monitoring" method, which means that the test equipment will introduce additional leakage current and distributed capacitance, changing the voltage distribution of the switch or even the surge arrester body, which will affect the long-term operating life of the surge arrester body. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the voltage drop method in the prior art is not applicable to the monitoring of power electronic controllable surge arresters, thereby providing an online monitoring device, system and method for controllable surge arresters.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] In a first aspect, embodiments of the present invention provide an online monitoring device for a controllable surge arrester, comprising: a current sampling module, which is used to collect leakage currents of the controllable part and the switching part of the controllable surge arrester; a voltage sampling module, which is used to collect system voltage; and a digital signal processing module, which is used to calculate various types of current parameters of the controllable surge arrester and the switching part based on the system voltage, the leakage current of the controllable part and the leakage current of the switching part, and send the various types of current parameters to the monitoring backend.

[0010] In one embodiment, the switching section includes a power electronic switch, a resistor, and a voltage-equalizing capacitor connected in parallel, and various types of current parameters including: total current, resistive current, capacitive current, and resistive harmonic current of a preset number.

[0011] In one embodiment, the online monitoring device for the controllable surge arrester further includes: a temperature acquisition module for acquiring the ambient temperature of the controllable surge arrester; and a digital signal processing module for correcting various types of current parameters based on the ambient temperature and then sending them to the monitoring backend.

[0012] In one embodiment, the online monitoring device for the controllable surge arrester further includes a communication module, which is used to realize information transmission between the digital signal processing module and the monitoring backend.

[0013] Secondly, embodiments of the present invention provide an online monitoring system for a controllable surge arrester, including at least one online monitoring device and a monitoring backend, wherein the digital signal processing module of each online monitoring device sends multiple types of current parameters to the monitoring backend; the monitoring backend compares the multiple types of current parameters with the electrical life test parameters of the controllable surge arrester throughout the entire process to obtain the corresponding health index of the controllable surge arrester.

[0014] In one embodiment, the monitoring backend classifies the electrical life status of the controllable surge arrester into a healthy state, a sub-healthy state, a dangerous state, and a failure state based on the full-process electrical life test parameters of the controllable surge arrester, with each state corresponding to a health index within a preset range.

[0015] In one embodiment, the monitoring backend determines the current state of the controllable surge arrester based on the health index and the health index within a preset range corresponding to each state.

[0016] In one embodiment, the online monitoring system for the controllable surge arrester further includes a display module for displaying health indices and the current status of the controllable surge arrester.

[0017] In one embodiment, the online monitoring system for the controllable surge arrester further includes an alarm module, which is used to issue a corresponding alarm signal when the current state of the controllable surge arrester is a sub-healthy state, a dangerous state, or a failure state.

[0018] Thirdly, embodiments of the present invention provide an online monitoring method for a controllable surge arrester, applied to the online monitoring system for the controllable surge arrester of the second aspect. The method includes: collecting system voltage, leakage current of the controllable part, and leakage current of the switching part; calculating various types of current parameters of the controllable surge arrester and the switching part based on the system voltage, leakage current of the controllable part, and leakage current of the switching part; comparing the various types of current parameters with the electrical life test parameters of the controllable surge arrester throughout the entire process to obtain a health index of the controllable surge arrester; and determining the current state of the controllable surge arrester based on the health index and the health index within a preset range corresponding to each state.

[0019] In one embodiment, before determining the current state of the controllable surge arrester based on the health index and the health index within a preset range corresponding to each state, the method further includes: dividing the entire electrical life state of the controllable surge arrester into a healthy state, a sub-healthy state, a dangerous state, and a failure state based on the full-process electrical life test parameters of the controllable surge arrester, wherein each state corresponds to a health index within a preset range.

[0020] The technical solution of this invention has the following advantages:

[0021] The online monitoring device provided by this invention includes a current sampling module for collecting leakage current from both the controllable and switching components; a voltage sampling module for collecting system voltage; and a digital signal processing module for calculating various types of current parameters for the controllable surge arrester and switching components based on the system voltage, leakage current from the controllable and switching components, and sending these parameters to the monitoring backend. This invention uses the leakage current of the power electronic switch as a characteristic quantity, enabling non-invasive detection. It has broad application market potential for monitoring the state of power electronic switches in enclosed, compact environments with strict leakage current limitations, understanding the electrical lifespan of power electronic switches, and ensuring their safe and reliable operation. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 A composition diagram of a specific example of a controllable surge arrester provided in an embodiment of the present invention;

[0024] Figure 2 A composition diagram of a specific example of the online monitoring device provided in an embodiment of the present invention;

[0025] Figure 3 A composition diagram of another specific example of the online monitoring device provided in an embodiment of the present invention;

[0026] Figure 4a The trends of total current and capacitive current variation are provided in the embodiments of the present invention;

[0027] Figure 4b The resistive current variation trend provided in the embodiments of the present invention;

[0028] Figure 5 The leakage current of a single-layer switch varies with voltage, as provided in this embodiment of the invention.

[0029] Figure 6 A composition diagram of another specific example of the online monitoring device provided in an embodiment of the present invention;

[0030] Figure 7 A composition diagram of another specific example of the online monitoring device provided in an embodiment of the present invention;

[0031] Figure 8 A composition diagram of a specific example of an online monitoring system provided in an embodiment of the present invention;

[0032] Figure 9 This is a composition diagram of another specific example of an online monitoring system provided in an embodiment of the present invention.

[0033] Figure Labels

[0034] 1-Online monitoring device; 2-Monitoring backend; 3-Display module; 4-Alarm module; 11-Current sampling module; 12-Voltage sampling module; 13-Digital signal processing module; 14-Temperature acquisition module; 15-Communication module. Detailed Implementation

[0035] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0037] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0038] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0039] Example 1

[0040] To ensure the safe and reliable operation of power electronic switches, effectively prevent system function loss or even further deterioration into catastrophic failure caused by potential early faults, issue timely warnings when equipment performance deteriorates, and avoid changing the voltage distribution of surge arresters by adding voltage monitoring circuits, this invention provides an online monitoring device for controllable surge arresters. This prior monitoring device is a non-intrusive monitoring device based on leakage current.

[0041] like Figure 1 As shown, the controllable surge arrester includes a fixed part, a controllable part, and a switching part. The fixed part and the controllable part are connected in series. The first end of the switching part is connected to the first end of the controllable part. The second end of the switching part and the second end of the controllable part are both grounded. The fixed part and the controllable part are both composed of at least one valve branch connected in parallel. Each valve branch is composed of multiple resistors connected in series. The switching part mainly includes a power electronic switch.

[0042] like Figure 2 As shown, the online monitoring device of this embodiment includes: a current sampling module 11, a voltage sampling module 12, and a digital signal processing module 13.

[0043] Specifically, the current sampling module 11 is used to collect the leakage current of the controllable part and the switching part respectively. Since the leakage current of the power electronic switch in the switching part changes with the voltage, when the voltage of the power electronic device changes due to factors such as short circuit, moisture, aging, etc., the leakage current of the power electronic switch will also change. Therefore, the status of the power electronic switch can be monitored by non-invasive measurement of the leakage current of the power electronic switch.

[0044] Specifically, the voltage sampling module 12 is used to collect the system voltage; the digital signal processing module 13 is used to calculate various types of current parameters of the controllable surge arrester and the switching part based on the system voltage, the leakage current of the controllable part and the leakage current of the switching part, and send the various types of current parameters to the monitoring backend 2.

[0045] like Figure 3 As shown, the switching section includes a power electronic switch, a resistor, and a voltage-equalizing capacitor connected in parallel. The power electronic switch can be composed of two anti-parallel thyristors, and it is a controllable power device. In order to comprehensively monitor the status of the power electronic switch based on multiple types of current parameters, it is necessary to calculate the various types of current parameters of the controllable surge arrester and the switching section in reverse, based on the system voltage, the leakage current of the controllable section, and the leakage current of the switching section.

[0046] It should be noted that the calculation methods involved in the data processing module are all existing technologies and common knowledge methods for calculating the derived parameters of leakage current, and will not be elaborated here.

[0047] Optionally, various types of current parameters include: full current, resistive current, capacitive current, and resistive harmonic current of a preset order.

[0048] Specifically, in this embodiment of the invention, the curves of the total current, capacitive current, and resistive current of the switching section as a function of voltage U, measured at room temperature, are shown below. Figure 4a and Figure 4b As shown, Figure 4a The trends of total current and capacitive current are shown. Figure 4b This represents the trend of resistive current change.

[0049] Depend on Figure 4a and Figure 4b For capacitive current I C The fitting yields:

[0050] I C =0.73153+0.73481*U (1)

[0051] For resistive current I R The fitting yields:

[0052] IR =69.29986+5.58032*e (u / 0.97872) (2)

[0053] Assuming the normal operating voltage of a single-layer power electronic switch is 3kV, with a total of 32 layers connected in series, if two layers of internal components are short-circuited, ideally the voltage of the remaining layers would increase by an average of 195V. Table 2 shows the changes in leakage current at critical locations within the power electronic switch. When two layers of internal components are short-circuited, the capacitive current at other locations increases by an average of 106uA, an average increase of 3.8%; the resistive current increases by an average of 15.61uA, an average increase of 9.31. The leakage current increases due to the short circuit, meaning that changes in leakage current can reflect internal short-circuit faults, and the increase in resistive leakage current is more pronounced.

[0054] Table 1

[0055]

[0056] Therefore, the embodiments of the present invention directly determine the state of the power electronic switch based on the changes in the total current, resistive current, capacitive current and resistive harmonic current of a preset number.

[0057] Specifically, the monitoring backend 2 compares various types of current parameters and the electrical life test parameters of the controllable surge arrester throughout the entire process to obtain the health index of the controllable surge arrester.

[0058] This invention embodiment can first test the entire life cycle of the controllable surge arrester to obtain full-process electrical life test parameters. These test parameters can include total current, resistive current, capacitive current, and resistive harmonic current parameters of a preset number. Furthermore, the entire life cycle of the controllable surge arrester can be segmented, for example: healthy state, sub-healthy state, dangerous state, and failure state. Each state corresponds to a different range of electrical life test parameters. By comparing the various types of current parameters obtained in real time with the full-process electrical life test parameters of the controllable surge arrester, the health index of the controllable surge arrester, i.e., the state of the controllable surge arrester, can be obtained.

[0059] In one specific embodiment, the leakage current of power electronic devices is significantly affected by temperature. When the test temperature is changed in the example above, and a short-circuit fault exists in some components of the switch, the increase in the average resistive leakage current Ir and related derived parameters is as follows: Figure 5 As shown.

[0060] Therefore, as Figure 6As shown, the online monitoring device for the controllable surge arrester in this embodiment of the invention further includes: a temperature acquisition module 14, which is used to acquire the ambient temperature of the controllable surge arrester. The temperature acquisition module 14 mainly includes a temperature sensor; the digital signal processing module 13 also corrects various types of current parameters based on the ambient temperature and sends them to the monitoring backend 2.

[0061] It should be noted that the correction methods involved in the digital signal processing module 13 are all existing and mature methods for correcting the acquired signals based on temperature, and will not be elaborated here.

[0062] In one specific embodiment, such as Figure 7 As shown, the online monitoring device for the controllable surge arrester also includes a communication module 15, which is used to realize information transmission between the digital signal processing module 13 and the monitoring backend 2. This communication module 15 can be a wireless communication module, and there are no restrictions on its use here.

[0063] Example 2

[0064] This invention provides an online monitoring system for controllable surge arresters, such as... Figure 8 As shown, the system includes at least one online monitoring device 1 and a monitoring backend 2 according to Embodiment 1. The digital signal processing module 13 of each online monitoring device 1 sends multiple types of current parameters to the monitoring backend 2. The monitoring backend 2 compares the multiple types of current parameters with the electrical life test parameters of the controllable surge arrester throughout the entire process to obtain the corresponding health index of the controllable surge arrester.

[0065] Specifically, in the actual operation of suppressing system overvoltage, multiple controllable surge arresters need to be installed in the system. Each controllable surge arrester can be equipped with an online monitoring device 1. Each online monitoring device 1 collects the leakage current of the controllable part, the leakage current of the switching part, and the system voltage of the controllable surge arrester in real time, and calculates various types of current parameters based on the aforementioned parameters, and sends all types of current parameters to the monitoring backend 2.

[0066] Optionally, the monitoring backend 2, based on the full-process electrical life test parameters of the controllable surge arrester, divides the full-process electrical life status of the controllable surge arrester into healthy state, sub-healthy state, dangerous state, and failure state, where each state corresponds to a preset range of health index. The monitoring backend 2 determines the current state of the controllable surge arrester based on the health index and the health index within the preset range corresponding to each state.

[0067] Monitoring backend 2 uses a health index to describe the status of controllable surge arresters. The health index is obtained by comparing on-site test results with parameters from the full-process electrical life test. The health index ranges from 0 to 100; a health index closer to 100 indicates a healthier device, while a lower index indicates poorer performance or even impending failure. Figure 6As shown, the health index is divided into healthy state, sub-healthy state, dangerous state and failure state. Based on the degree to which the current state of the system deviates from the healthy state, necessary maintenance and repair measures are taken to slow down the equipment performance degradation process, so as to avoid catastrophic failures that paralyze the entire system, thereby improving the safety and reliability of the equipment.

[0068] In one specific embodiment, such as Figure 9 As shown, the online monitoring system for the controllable surge arrester also includes a display module 3, which displays the health index and the current status of the controllable surge arrester. This display module 3 can be an LED display screen, which can display the current status of the controllable surge arrester in sections or pages, or display the leakage current parameters of the controllable surge arrester.

[0069] In one specific embodiment, such as Figure 9 As shown, the online monitoring system for the controllable surge arrester also includes an alarm module 4, which is used to issue corresponding alarm signals when the current state of the controllable surge arrester is in a sub-healthy state, a dangerous state, or a failure state. This alarm module 4 can be an audible and visual alarm module, with different alarm signals corresponding to the sub-healthy state, dangerous state, and failure state. For example, a yellow light corresponds to a sub-healthy state, a blue light to a dangerous state, and a red light to a failure state, etc.

[0070] Example 3

[0071] This invention provides an online monitoring method for a controllable surge arrester, applied to the online monitoring system for the controllable surge arrester in Embodiment 1. The method includes:

[0072] (1) Collect system voltage, leakage current of controllable part and leakage current of switch part.

[0073] (2) Based on the system voltage, the leakage current of the controllable part and the leakage current of the switching part, various types of current parameters of the controllable surge arrester and the switching part are calculated.

[0074] (3) By comparing various types of current parameters and the electrical life test parameters of the controllable surge arrester throughout the entire process, the health index of the controllable surge arrester is obtained.

[0075] (4) Determine the current state of the controllable surge arrester based on the health index and the health index within the preset range corresponding to each state.

[0076] Specifically, the leakage current of the power electronic switch of the controllable surge arrester changes with the voltage. When the voltage of the power electronic switch is changed due to factors such as short circuit, moisture, or aging of internal components, the leakage current of the power electronic switch will also change. Therefore, this embodiment of the invention adopts a non-intrusive leakage current monitoring method to monitor the status of the power electronic switch.

[0077] Specifically, such as Figure 3As shown, the switching section includes a power electronic switch, a resistor, and a voltage-equalizing capacitor connected in parallel. The power electronic switch can be composed of two anti-parallel thyristors, and is a controllable power device. To comprehensively monitor the state of the power electronic switch based on multiple types of current parameters, it is necessary to calculate various types of current parameters for the controllable surge arrester and the switching section in reverse, based on the system voltage, the leakage current of the controllable section, and the leakage current of the switching section. These multiple types of current parameters include: total current, resistive current, capacitive current, and resistive harmonic current of a preset order.

[0078] Specifically, in this embodiment of the invention, the entire life cycle of the controllable surge arrester can be tested first to obtain the electrical life test parameters for the entire process. These test parameters may include the total current, resistive current, capacitive current, and resistive harmonic current parameters of a preset number. Furthermore, the entire life cycle of the controllable surge arrester can be segmented, for example: healthy state, sub-healthy state, dangerous state, and failure state. Each state corresponds to a different range of electrical life test parameters. The various types of current parameters obtained in real time are compared with the electrical life test parameters of the controllable surge arrester to obtain the health index of the controllable surge arrester, that is, the state of the controllable surge arrester.

[0079] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An online monitoring device for a controllable surge arrester, characterized in that, include: The current sampling module is used to collect the leakage current of the controllable part and the switching part of the controllable surge arrester, respectively. Voltage sampling module, which is used to collect system voltage; The digital signal processing module is used to calculate various types of current parameters of the controllable surge arrester and the switching part based on the system voltage, the leakage current of the controllable part and the leakage current of the switching part, and send the various types of current parameters to the monitoring backend. The switching section includes a power electronic switch, a resistor, and a voltage equalizing capacitor connected in parallel. The various types of current parameters include: total current, resistive current, capacitive current, and resistive harmonic current of a preset order. Based on the system voltage, leakage current of the controllable part and leakage current of the switching part, various types of current parameters of the controllable surge arrester and the switching part are calculated in reverse. Based on the trends of total current, capacitive current, and resistive current, fit the capacitive current and resistive current.

2. The online monitoring device for a controllable surge arrester according to claim 1, characterized in that, Also includes: A temperature acquisition module is used to acquire the ambient temperature of the controllable surge arrester. The digital signal processing module also corrects the various types of current parameters based on the ambient temperature before sending them to the monitoring backend.

3. The online monitoring device for a controllable surge arrester according to claim 1, characterized in that, Also includes: A communication module is used to realize information transmission between the digital signal processing module and the monitoring backend.

4. An online monitoring system for a controllable surge arrester, characterized in that, Includes at least one online monitoring device and monitoring backend as described in any one of claims 1-3, wherein, The digital signal processing module of each of the online monitoring devices sends the various types of current parameters to the monitoring backend. The monitoring backend compares the various types of current parameters with the full-process electrical life test parameters of the controllable surge arrester to obtain the corresponding health index of the controllable surge arrester.

5. The online monitoring system for controllable surge arresters according to claim 4, characterized in that, Based on the full-process electrical life test parameters of the controllable surge arrester, the monitoring backend divides the full-process electrical life status of the controllable surge arrester into healthy state, sub-healthy state, dangerous state and failure state, with each state corresponding to a health index within a preset range.

6. The online monitoring system for controllable surge arresters according to claim 5, characterized in that, The monitoring backend determines the current state of the controllable surge arrester based on the health index and the health index within a preset range corresponding to each state.

7. The online monitoring system for controllable surge arresters according to claim 6, characterized in that, Also includes: The display module is used to display the health index and the current status of the controllable surge arrester.

8. The online monitoring system for controllable surge arresters according to claim 6, characterized in that, Also includes: The alarm module is used to issue corresponding alarm signals when the current state of the controllable surge arrester is in a sub-healthy state, a dangerous state, or a failed state.

9. An online monitoring method for a controllable surge arrester, characterized in that, The method, applied to the online monitoring system of the controllable surge arrester according to any one of claims 5-8, comprises: The system voltage, the leakage current of the controllable part, and the leakage current of the switching part are collected. Based on the system voltage, the leakage current of the controllable part and the leakage current of the switching part, various types of current parameters of the controllable surge arrester and the switching part are calculated. By comparing the various types of current parameters with the full-process electrical life test parameters of the controllable surge arrester, the health index of the controllable surge arrester is obtained. The current state of the controllable surge arrester is determined based on the health index and the health index within a preset range corresponding to each state.

10. The online monitoring method for a controllable surge arrester according to claim 9, characterized in that, Before determining the current state of the controllable surge arrester based on the health index and the health index within a preset range corresponding to each state, the method further includes: Based on the full-process electrical life test parameters of the controllable surge arrester, the full-process electrical life status of the controllable surge arrester is divided into healthy state, sub-healthy state, dangerous state and failure state, where each state corresponds to a health index within a preset range.

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