System for testing grid voltage spikes based on dynamic triggering

Abstract

The application provides a power grid voltage spike test system based on dynamic triggering, which realizes reliable capture and cause analysis of spikes through dynamic triggering threshold and device action time synchronization technology. The test system comprises a signal conditioning module, an analog-digital conversion module, a multi-source synchronous acquisition module, a cause analysis engine and a dynamic triggering module. Dynamic triggering conditions are set in the dynamic triggering module, the main characteristics of the power grid voltage spikes meeting the dynamic triggering conditions are matched with the main characteristics of the power grid voltage spikes preexisting in the rule base in the cause analysis engine, and the power grid voltage spike signals caused by device action are identified by checking the device action information and the power grid voltage spike timestamp.

Description

TECHNICAL FIELD

[0001] The present application relates to a voltage test system, in particular to a power grid voltage spike test system, belonging to the technical field of power system test. BACKGROUND

[0002] With the development of science and technology, high-power electrical equipment is continuously applied, which also causes more conducted interference problems on the power grid. Especially, when the high-power electrical equipment starts or stops or changes the working condition, it will generate a large degree of power line voltage spike on the power grid. In order to effectively cope with this power grid conducted interference, it is necessary to effectively measure the characteristics of the power line voltage spike signal.

[0003] However, the existing power grid voltage spike test technology has the following problems.

[0004] (1) Low capture rate: the traditional oscilloscope or power quality analyzer uses a fixed threshold trigger (such as ±500V), which cannot adapt to power grid fluctuations, resulting in missed microsecond-level spikes.

[0005] (2) Many false triggers: harmonics, oscillations and other disturbances in industrial environments are easily misjudged as spikes.

[0006] (3) Isolated data: the test results are not associated with the device working state (such as motor start-stop, relay action), making it difficult to trace the source of interference. SUMMARY

[0007] Therefore, the present application proposes a power grid voltage spike test system based on dynamic triggering, which realizes reliable capture and cause analysis of spikes through dynamic triggering threshold and device action time synchronization technology.

[0008] The technical scheme of the present application is: a power grid voltage spike test system based on dynamic triggering, comprising:

[0009] a signal conditioning module for acquiring the measured power grid voltage signal and performing isolation and voltage reduction processing on the acquired voltage signal;

[0010] an analog-to-digital conversion module for analog-to-digital conversion of the analog signal output by the signal conditioning module and sending the converted digital signal to the dynamic triggering module;

[0011] a multi-source synchronous acquisition module for collecting and recording the action information of a plurality of set devices connected to the power grid under test and sending the action information to the dynamic triggering module;

[0012] a cause analysis engine pre-storing a rule base, wherein the rule base defines the corresponding relationship between the main characteristics of the power grid voltage spike and the device action;

[0013] The dynamic trigger module is preset with a dynamic trigger condition of voltage spike test; the dynamic trigger module sends the main features of the power grid voltage spike meeting the dynamic trigger condition in the received digital signal to the cause analysis engine; the cause analysis engine matches the main features of the power grid voltage spike with the preexisting rules in the rule base, and the dynamic trigger module judges the power grid voltage spike meeting the dynamic trigger condition according to the matching result and further checks the time stamp of the device action information and the power grid voltage spike to identify the power grid voltage spike signal caused by the device action.

[0014] As a preferred mode of the present application: further comprising a data storage module, which records the voltage spike signal caused by the device action and the device action information associated with the voltage spike time stamp.

[0015] As a preferred mode of the present application: when the cause analysis engine performs the matching of the power grid voltage spike features:

[0016] If the power grid voltage spike is matched successfully, the cause analysis engine feeds back a signal of successful matching to the dynamic trigger module; the dynamic trigger module further checks whether the device action information is associated with the time stamp of the power grid voltage spike:

[0017] If the device action information is associated with the time stamp of the power grid voltage spike, it indicates that the power grid voltage spike is caused by the device action; if the device action information is not associated with the time stamp of the power grid voltage spike, it indicates that the power grid voltage spike is not caused by the device action.

[0018] If the power grid voltage spike is not matched successfully, the cause analysis engine feeds back a signal of unsuccessful matching to the dynamic trigger module; the dynamic trigger module further checks whether the device action information is associated with the time stamp of the power grid voltage spike:

[0019] If the device action information is associated with the time stamp of the power grid voltage spike, it indicates that the power grid voltage spike is caused by the device action, but there is no corresponding record in the rule base; at this time, the main features of the power grid voltage spike and the corresponding device action information are sent to the cause analysis engine, which adds them to the rule base; if the device action information is not associated with the time stamp of the power grid voltage spike, it indicates that the power grid voltage spike is not caused by the device action.

[0020] As a preferred mode of the present application: the method for associating the device action information with the time stamp of the power grid voltage spike is:

[0021] The dynamic trigger module receives the digital signal of the grid voltage signal output by the analog-digital conversion module and the device action information collected by the multi-source synchronous collection module, stores and compares the time stamp of the device action information with the time stamp of the grid voltage spike in the digital signal, and establishes the time stamp association.

[0022] As a preferred mode of the present application: the main features of the grid voltage spike include: frequency, pulse width, amplitude;

[0023] When the cause analysis engine performs matching on the grid voltage spike features, if the errors of the frequency, pulse width and amplitude are within the respective set error ranges, it is considered that the matching is successful.

[0024] As a preferred mode of the present application: the dynamic trigger condition is that the voltage spike reaches the voltage spike test threshold, and the dynamic trigger module updates the dynamic trigger condition in real time or according to a set frequency.

[0025] As a preferred mode of the present application: the calculation formula of the voltage spike test threshold is:

[0026] V threshold =V baseline ±(K×V noise )

[0027] Wherein, V threshold is the threshold of the grid voltage spike test;

[0028] V baseline is the grid voltage baseline;

[0029] V noise is the noise voltage of the measured grid;

[0030] K is an adjustable coefficient;

[0031] The dynamic trigger module calculates the grid voltage baseline V baseline and the grid noise voltage V noise in real time or according to a set frequency based on the digital signal of the grid voltage output by the analog-digital conversion module, to update the voltage spike test threshold.

[0032] As a preferred mode of the present application: the grid voltage baseline is calculated by moving average or median filtering; the noise voltage of the measured grid is periodically measured when the grid is in a non-powered state or is obtained in real time based on a sliding window, after the noise voltage is isolated from the grid fundamental voltage by the high-pass filtering measure in the signal conditioning module.

[0033] Advantages:

[0034] (1) The test system of the present application adopts a dynamic threshold, which can adapt to power grid fluctuations, thereby effectively improving the capture rate of power grid voltage spikes. Tests show that the dynamic threshold improves the spike detection rate from 60% to 95% (actual measurement data).

[0035] (2) The test system of the present application has a low false touch, and the matching power grid voltage spike characteristic value considers the pulse width, which can make the discrimination false alarm rate < 5%.

[0036] (3) The test system of the present application associates the power grid voltage spike with the device action, and the traceability is convenient; through the association with the device action, the spike source (such as power-on of a certain functional module, discharge of a certain relay coil, etc.) can be quickly located. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0038] Figure 1 The figure is a schematic diagram of the architecture of the power grid voltage spike test system based on dynamic triggering of the present application. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0040] The present application will be described in detail below in combination with the drawings and preferred embodiments, so that the advantages and features of the present application can be more easily understood by those skilled in the art, and the scope of protection of the present application can be more clearly and explicitly defined.

[0041] The present embodiment provides a power grid voltage spike test system based on dynamic triggering, which can detect and record power grid voltage spike signals in real time, and is especially suitable for transient disturbance testing in scenarios such as frequency converters, high-power motors, etc.

[0042] As shown in Figure 1 The test system includes a signal conditioning module, an analog-to-digital conversion (ADC) module, a multi-source synchronous acquisition module, a cause analysis engine, and a dynamic triggering module. The signal conditioning module and the analog-to-digital conversion module are electrically connected, and the dynamic triggering module is electrically connected with the analog-to-digital conversion module, the multi-source synchronous acquisition module, and the cause analysis engine.

[0043] The signal conditioning module is directly connected with the measured power grid (such as through a voltage probe to access the 380V bus of the measured power grid), and is used to obtain the voltage signal of the measured power grid. The signal conditioning module performs lossless isolation and voltage reduction on the input voltage signal of the measured power grid within a set bandwidth, and generally needs to include high-voltage isolation (such as an optical coupler or a Hall sensor), high-pass filtering and other measures; the analog signal output after the signal conditioning module should reach the order of magnitude that can be analyzed by the subsequent analog-to-digital conversion module, which is generally below 10Vrms.

[0044] The analog-to-digital conversion module is used to collect data of the analog signal output by the signal conditioning module, then perform analog-to-digital conversion, and send the digital signal after analog-to-digital conversion to the dynamic triggering module.

[0045] As an example, considering the specific requirements of power grid voltage spike testing, the bandwidth of analog-to-digital conversion is generally not less than 10MHz, the sampling rate should be higher than 20MHz, the sampling bit number is generally not less than 12 bits, and anti-aliasing filtering measures are provided.

[0046] The multi-source synchronous acquisition module synchronously acquires and records the action information (such as power-on of a certain functional module, PLC control signal, contactor on-off timing, etc.) of multiple set devices accessing the power grid to be tested; it can be understood that "multi-source" here refers to the acquisition of action information of multiple devices; "synchronous" refers to the acquisition timing being consistent with the device action timing, and the information acquisition is performed synchronously when the device acts.

[0047] As an example, the multi-source synchronous acquisition module can be implemented by using an FPGA.

[0048] The cause analysis engine matches the power grid voltage spike characteristics with the device action (here, "device" refers to one or more of the multiple set devices accessing the power grid to be tested) through an internally preset rule library. Specifically, the rule library defines the corresponding relationship between the main characteristics (including frequency, pulse width, amplitude, etc.) of the power grid voltage spike and the device action; the corresponding relationship can be referenced from existing data or determined by itself; the device action is, for example, the IGBT switching action of a frequency converter (the IGBT switching of the frequency converter causes a 5kHz oscillation superimposed on the spike). Initially, the rule library only records the corresponding relationship between the main characteristics (including frequency, pulse width, amplitude, etc.) of the known power grid voltage spike and the device action.

[0049] The cause analysis engine and the dynamic triggering module can perform bidirectional transmission of signals, and the cause analysis engine sends the matched cause result to the dynamic triggering module.

[0050] As an example, the cause analysis engine is implemented by using an FPGA.

[0051] The dynamic triggering module is the core of the system, and its main functions include:

[0052] (1) Receiving the digital signal output by the analog-to-digital conversion module and the device action information collected by the multi-source synchronous acquisition module, storing and comparing the time stamp of the device action information (i.e. the time when the device action signal occurs) with the time stamp of the grid voltage spike in the digital signal (i.e. the occurrence time of the grid voltage spike) to establish a time stamp association and determine the corresponding relationship between the grid voltage spike and the device action information.

[0053] (2) The dynamic trigger module has preset trigger conditions for voltage spike testing according to test needs. The trigger conditions are dynamic trigger conditions, and the dynamic trigger module updates the trigger conditions in real time or according to a set frequency.

[0054] After the dynamic trigger module receives the digital signal of the grid voltage sent by the analog-to-digital conversion module, if there is a voltage spike in the digital signal that meets the preset dynamic trigger condition, i.e. there is a grid voltage spike that meets the preset dynamic trigger condition, the dynamic trigger module is triggered, and the main characteristics (including frequency, pulse width, amplitude, etc.) of the current grid voltage spike are sent to the cause analysis engine; in the cause analysis engine, the grid voltage spike characteristics pre-existing in the rule base are matched:

[0055] If the grid voltage spike is matched successfully (i.e. there is a matching voltage spike characteristic in the rule base), the cause analysis engine feeds back a signal of successful matching to the dynamic trigger module; the dynamic trigger module further checks whether the time stamps of the device action information and the grid voltage spike are associated:

[0056] If the device action information is associated with the time stamp of the grid voltage spike (i.e. the occurrence time of the grid voltage spike is consistent with the device action time), it indicates that the grid voltage spike is the voltage spike of interest, i.e. the voltage spike signal is caused by device action; if the device action information is not associated with the time stamp of the grid voltage spike (i.e. the occurrence time of the grid voltage spike is not consistent with the device action time, or in other words, there is no device action at the occurrence time of the grid voltage spike), it indicates that the grid voltage spike is not caused by device action, and there is no need to pay attention to the voltage spike.

[0057] If the grid voltage spike is not matched successfully (i.e. there is no matching spike characteristic in the rule base), the cause analysis engine feeds back a signal of unsuccessful matching to the dynamic trigger module; the dynamic trigger module further checks whether the time stamps of the device action information and the grid voltage spike are associated:

[0058] If the device action information is associated with the timestamp of the grid voltage spike (i.e. the occurrence time of the grid voltage spike is consistent with the device action time), it indicates that the grid voltage spike is a voltage spike of interest (i.e. it indicates that the voltage spike signal is caused by device action), but there is no corresponding record in the rule base, at this time, the grid voltage spike is recorded, and the device action information and the grid voltage spike information are sent to the cause analysis engine, which adds them to the rule base to update the rule base. If the device action information is not associated with the timestamp of the grid voltage spike (i.e. the occurrence time of the grid voltage spike is not consistent with the device action time, or in other words, there is no device action at the occurrence time of the grid voltage spike), it indicates that the grid voltage spike is not caused by device action, and there is no need to pay attention to the voltage spike.

[0059] It can be understood that: after the analog-to-digital conversion module sends the digital signal of the analog-to-digital converted grid voltage to the dynamic trigger module, if there is no voltage spike in the digital signal that meets the preset dynamic trigger condition, the dynamic trigger module will not be triggered and will not perform subsequent processing.

[0060] As an example, for frequency, it can be set that a successful match is considered to be within an error range of ±2%; for pulse width, it can be set that a successful match is considered to be within an error range of ±5%; and for amplitude, it can be set that a successful match is considered to be within an error range of ±10%.

[0061] For example: when the frequency converter is started, an 812V / 4μs spike (i.e. a successful match of the grid voltage spike) is captured, and an IGBT on signal is recorded synchronously (i.e. the timestamp of the grid voltage spike is associated with the timestamp of the device action information), and it is determined that the voltage spike is a switching transient overvoltage.

[0062] The dynamic trigger module sets the dynamic trigger condition for voltage spike testing according to test needs, and the dynamic trigger condition is that the voltage spike reaches a voltage spike test threshold (i.e. the voltage spike is greater than or equal to the voltage spike test threshold). The calculation formula of the voltage spike test threshold is:

[0063] V threshold =V baseline ±(K×V noise )

[0064] Wherein, V threshold is the voltage spike test threshold, which is considered to meet the trigger condition when it is higher than the threshold;

[0065] V baseline is the grid voltage baseline;

[0066] V noise is the noise voltage of the measured grid;

[0067] K is an adjustable coefficient (e.g. 1.5-3).

[0068] The dynamic triggering module calculates the grid voltage baseline V baseline and the grid noise voltage V noise in real time (or at a set frequency) based on the digital signal of the grid voltage output by the analog-digital conversion module; thus, the voltage spike threshold is a dynamic threshold.

[0069] The grid voltage baseline V baseline The calculation can adopt a moving average or median filtering method to avoid instantaneous fluctuation interference; as an example, the grid voltage baseline V baseline is obtained based on real-time calculation of a sliding window (e.g. the RMS value of the grid voltage in a 1ms window); the grid noise voltage V noise can be periodically measured when the grid is in a non-powered state; it can also be obtained based on real-time calculation of the noise voltage in the signal conditioning module after the grid fundamental voltage is isolated by a high-pass filtering measure.

[0070] In addition, the dynamic triggering module also performs real-time calculation of the frequency and pulse width of the grid impulse voltage; the frequency of the grid impulse voltage is obtained based on real-time calculation of a sliding window. Considering the specific requirements of the grid voltage spike test, only pulses with a duration of 0.1μs-10ms are generally captured, and high-frequency noise is suppressed.

[0071] As an example, the dynamic triggering module can be implemented using an FPGA.

[0072] As an example, the test system also includes a data storage module that records the voltage spike signals determined to be caused by device action and the device action information associated with the voltage spike timestamp.

[0073] As an example, the test system can realize interference tracing of a multi-device parallel system: through multi-channel synchronous acquisition, the conduction of a bus spike caused by the shutdown of a certain motor to an adjacent PLC power module is located.

[0074] In summary, the above is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A dynamic trigger based grid voltage spike testing system, characterized by: Comprise: A signal conditioning module for acquiring the measured grid voltage signal and isolating and reducing the voltage signal; An analog-to-digital conversion module for converting the analog signal output by the signal conditioning module into a digital signal and sending the converted digital signal to a dynamic trigger module; A multi-source synchronous acquisition module for synchronously acquiring and recording the action information of a plurality of set devices connected to the grid to be tested and sending the action information to the dynamic trigger module; A cause analysis engine pre-stored with a rule library defining the correspondence between the main characteristics of the grid voltage spike and the device action; A dynamic trigger module pre-set with a voltage spike test dynamic trigger condition; The dynamic trigger module sends the main characteristics of the grid voltage spike satisfying the dynamic trigger condition in the received digital signal to the cause analysis engine; the cause analysis engine matches the main characteristics of the grid voltage spike with the pre-stored rule library; the dynamic trigger module judges the grid voltage spike satisfying the dynamic trigger condition according to the matching result and further checks the time stamp of the device action information and the grid voltage spike to identify the grid voltage spike signal caused by the device action; The main characteristics of the grid voltage spike include frequency, pulse width, and amplitude; The dynamic trigger condition is that the voltage spike reaches a voltage spike test threshold, and the dynamic trigger module updates the dynamic trigger condition in real time or at a set frequency; The calculation formula of the voltage spike test threshold is: V threshold =V baseline ±(K×V noise ) wherein V threshold is the voltage spike test threshold; V baseline Vgridis the grid voltage baseline; V noise Vnoise is the noise voltage of the measured power grid; K is an adjustable coefficient; The dynamic triggering module calculates the grid voltage baseline V baseline and the grid noise voltage V noise in real time or according to a set frequency according to the digital signal of the grid voltage output by the analog-digital conversion module, to update the voltage spike test threshold. The grid voltage baseline is calculated by moving average or median filtering.

2. The dynamic trigger based grid voltage spike testing system of claim 1, wherein: Further comprising a data storage module for recording the voltage spike signal caused by the device action and the device action information associated with the voltage spike time stamp.

3. The dynamic trigger based grid voltage spike testing system of claim 1 or 2, wherein: When the cause analysis engine matches the main characteristics of the grid voltage spike: If the grid voltage spike is matched successfully, the cause analysis engine feeds back a signal of successful matching to the dynamic trigger module; the dynamic trigger module further checks whether the time stamp of the device action information and the grid voltage spike is associated: If the time stamp of the device action information and the grid voltage spike is associated, it indicates that the grid voltage spike is caused by the device action; if the time stamp of the device action information and the grid voltage spike is not associated, it indicates that the grid voltage spike is not caused by the device action; If the grid voltage spike is not matched successfully, the cause analysis engine feeds back a signal of unsuccessful matching to the dynamic trigger module; the dynamic trigger module further checks whether the time stamp of the device action information and the grid voltage spike is associated: If the time stamp of the device action information and the grid voltage spike is associated, it indicates that the grid voltage spike is caused by the device action, but there is no corresponding record in the rule library; at this time, the main characteristics of the grid voltage spike and the corresponding device action information are sent to the cause analysis engine, which adds them to the rule library; if the time stamp of the device action information and the grid voltage spike is not associated, it indicates that the grid voltage spike is not caused by the device action.

4. The dynamic trigger based grid voltage spike testing system of claim 3, wherein: The method for associating the time stamp of the device action information and the grid voltage spike is: The dynamic trigger module receives the digital signal of the grid voltage output by the analog-digital conversion module and the device action information collected by the multi-source synchronous collection module, stores and compares the time stamp of the device action information with the time stamp of the grid voltage spike in the digital signal, and establishes the time stamp association.

5. The dynamic trigger based grid voltage spike testing system of claim 3, wherein: When the frequency, pulse width, and amplitude errors are within the respective error ranges, the cause analysis engine considers that the matching is successful.

6. The dynamic trigger based grid voltage spike testing system of claim 1, wherein: The noise voltage of the measured grid is periodically measured when the grid is in a non-powered state or is obtained based on real-time calculation of the signal conditioning module after the noise voltage isolated from the grid fundamental voltage by the high-pass filtering measure.

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