CN110783900B - Passive protection device and monitoring module and monitoring method thereof - Google Patents
Passive protection device and monitoring module and monitoring method thereof Download PDFInfo
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- CN110783900B CN110783900B CN201910974583.0A CN201910974583A CN110783900B CN 110783900 B CN110783900 B CN 110783900B CN 201910974583 A CN201910974583 A CN 201910974583A CN 110783900 B CN110783900 B CN 110783900B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
- H02H7/262—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of switching or blocking orders
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/261—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations
- H02H7/263—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured involving signal transmission between at least two stations involving transmissions of measured values
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/20—Systems supporting electrical power generation, transmission or distribution using protection elements, arrangements or systems
Abstract
The application relates to a passive protection device, a monitoring module and a monitoring method thereof, wherein the monitoring module comprises: the direct current bias voltage processing module is connected with the circuit; the first end of the connecting circuit inputs alternating current; the second end of the connecting circuit is respectively connected with the direct current bias voltage processing module and the full-wave rectification processing module; the output end of the direct current bias voltage processing module is connected with the first input end of the unipolar analog-to-digital conversion module of the passive protection device; the output end of the full-wave rectification processing module is connected with the second input end of the unipolar analog-to-digital conversion module. On one hand, the acquisition is carried out in an alternating current mode, on the other hand, the acquisition is carried out in a direct current mode, compared with the traditional device, the traditional analog-digital conversion module does not need to be improved or converted, the protection action speed is not influenced, the protection misoperation can be reliably prevented, and the defect of misoperation under the condition that a circuit is low in load exists in the passive protection device using the unipolar AD is overcome by adopting a low-cost scheme on the premise that the device speed is not reduced.
Description
Technical Field
The present disclosure relates to the field of voltage stability monitoring, and more particularly, to a passive protection device, and a monitoring module and a monitoring method thereof.
Background
At present, digital processing and digital display are mostly adopted in power systems such as relay protection equipment, power meters, industrial automation equipment and industrial automation control, but original signals of the equipment such as voltage, current, pressure, temperature and the like are analog signals which continuously change, so that the digital processing and digital display can be carried out after the analog signals which continuously change are converted into digital signals. The existing analog-to-digital (AD) converters are divided into unipolar AD converters and bipolar AD converters, wherein the unipolar AD converters have a simpler structure and a lower price; the bipolar analog-to-digital converter has a relatively complex structure and is expensive.
At present, a passive protection device using a CT (current transformer) to obtain energy (also called power taking) is often used to sample current by using a Unipolar AD (analog to digital conversion) module built in a CPU to reduce cost. In order to collect the alternating current, a direct current bias voltage which is half of the AD reference voltage is needed to generate so as to perform unipolar processing on the alternating current. When the line load is small, the passive protection device energy-taking loop works unstably, power supply fluctuation is generated, further bias voltage fluctuation is caused, the protection device collects false fault current, switch misoperation is caused, and the defect of misoperation under the condition of low line load exists in the passive protection device using the unipolar AD. The reason for this is that the AD reference voltage is unstable, and therefore, it is important to monitor the AD reference voltage.
Specifically, a unipolar AD, which is common in the conventional art, is shown in fig. 1, which is a schematic diagram of sampling with a bias voltage, and is a loop formed by a reference voltage VREF, wherein a 4.3V voltage outputs a stable AD reference voltage of 3.3V after passing through MD 7133. A bias voltage forming loop is shown in fig. 2, and 3.3V AD reference voltage enters a follower formed by integrated operational amplifiers after being divided by resistors; the bias voltage is half of the reference voltage, and all AD sampling alternating current inputs enter an AD channel after being raised by the bias voltage. When the bias voltage is kept to be half of VREF, the problem of sampling value abnormity can not occur. However, when the bias voltage cannot be held at half VREF, an abnormality occurs in the sampled value. As shown in fig. 3, the sampling waveform when the input ac current is 0 but the bias voltage cannot be held at half VREF indicates that sampling abnormality occurs when the reference voltage is unstable, and the protection device malfunctions. When the device power supply is unstable, the reference voltage fluctuates.
Disclosure of Invention
Therefore, a passive protection device, a monitoring module and a monitoring method thereof are needed to be provided, so that the defect of misoperation of the passive protection device under the condition of low load of a line is overcome by adopting a low-cost scheme on the premise of not reducing the speed of the passive protection device.
A monitoring module of a passive protection device, comprising: the direct current bias voltage processing module is connected with the circuit;
the first end of the connecting line is used for inputting alternating current;
the second end of the connecting circuit is respectively connected with the direct current bias voltage processing module and the full-wave rectification processing module;
the output end of the direct current bias voltage processing module is used for being connected with a first input end of a unipolar analog-to-digital conversion module of the passive protection device;
the output end of the full-wave rectification processing module is used for being connected with the second input end of the unipolar analog-to-digital conversion module of the passive protection device.
The monitoring module of the passive protection device is applied to the passive protection device, analog-digital reference voltage is passed through the monitoring device, on one hand, AD 1 st path channel is input in an alternating current mode for collection, on the other hand, AD 2 nd path channel is input in a direct current mode for collection, more accurate judgment conditions are favorably obtained, device misoperation is effectively prevented, and compared with the traditional device, the technical scheme hardly increases hardware cost, the traditional analog-digital conversion module is not required to be improved or changed, the protection action speed is not influenced, protection misoperation can be reliably prevented, and therefore the defect that the passive protection device using the unipolar AD has misoperation under the condition of low load of a circuit is overcome by adopting a low-cost scheme on the premise of not reducing the device speed.
In one embodiment, the monitoring module further includes a current fundamental wave effective value calculation module, and the current fundamental wave effective value calculation module is used for being connected with the output end of the unipolar analog-to-digital conversion module and calculating the current fundamental wave effective value according to the alternating current sampling value sequence.
In one embodiment, the monitoring module further includes a current true value calculation module, and the current true value calculation module is configured to be connected to the output end of the unipolar analog-to-digital conversion module, and calculate a current true value according to the dc sampling value sequence.
In one embodiment, the monitoring module further includes a determining module, the determining module is respectively connected to the current fundamental wave effective value calculating module and the current true value calculating module, and the determining module is configured to determine that a fault occurs when the current fundamental wave effective value exceeds a preset first threshold range and the current true value exceeds a preset second threshold range.
In one embodiment, the monitoring module further includes a control module, the control module is connected to the judging module, and the control module is further configured to be connected to a protection component of the passive protection device; the control module is used for controlling the protection component to protect when the fault is determined to occur.
In one embodiment, the monitoring module further comprises an alarm module, the alarm module is connected with the judging module, and the alarm module is used for sending out an alarm signal when a fault is determined.
A method of monitoring a passive protection device, comprising the steps of: inputting alternating current; the DC bias voltage processing module is used for realizing the unipolar processing of the AC current and inputting the unipolar processing of the AC current to a first input end of a unipolar analog-to-digital conversion module of the passive protection device; and the full-wave rectification processing module is adopted to realize the full-wave rectification processing of the alternating current and input the alternating current into a second input end of the unipolar analog-to-digital conversion module of the passive protection device.
In one embodiment, the monitoring method further comprises the steps of: calculating a current fundamental wave effective value according to the alternating current sampling value sequence, and calculating a current true value according to the direct current sampling value sequence; and determining that a fault occurs when the effective value of the current fundamental wave exceeds a preset first threshold range and the effective value of the current exceeds a preset second threshold range.
In one embodiment, the monitoring method further comprises the steps of: when the fault is determined, controlling a protection component of the passive protection device to protect; and/or, sending out an alarm signal.
In one embodiment, the passive protection device is realized by adopting any monitoring method and/or is provided with any monitoring module.
Drawings
Fig. 1 is a schematic diagram of a conventional art unipolar AD sampling with a bias voltage.
Fig. 2 is a schematic diagram of a bias voltage forming circuit of a unipolar AD in the prior art.
Fig. 3 is a diagram illustrating a sampling waveform when the bias voltage of the unipolar AD cannot be maintained at half VREF in the conventional art.
Fig. 4 is a schematic connection diagram according to an embodiment of the present application.
Fig. 5 is a schematic diagram of application connection according to another embodiment of the present application.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and that modifications may be made by one skilled in the art without departing from the spirit and scope of the application and it is therefore not intended to be limited to the specific embodiments disclosed below.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used in the description of the present application are for illustrative purposes only and do not denote a single embodiment.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the description of the present application, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Aiming at the defect that the prior passive protection device using the unipolar AD has the maloperation under the condition of low load of a line, the passive protection device is pertinently improved, and the defect can be solved by adopting a low-cost scheme on the premise of not reducing the speed of the device. In one embodiment of the present application, a monitoring module of a passive protection device includes: the direct current bias voltage processing module is connected with the circuit; the first end of the connecting line is used for inputting alternating current; the second end of the connecting circuit is respectively connected with the direct current bias voltage processing module and the full-wave rectification processing module; the output end of the direct current bias voltage processing module is used for being connected with a first input end of a unipolar analog-to-digital conversion module of the passive protection device; the output end of the full-wave rectification processing module is used for being connected with the second input end of the unipolar analog-to-digital conversion module of the passive protection device. The monitoring module of the passive protection device is applied to the passive protection device, analog-digital reference voltage is passed through the monitoring device, on one hand, the AD 1 st path channel is input in an alternating current mode for collection, on the other hand, the AD 2 nd path channel is input in a direct current mode for collection, more accurate judgment conditions are favorably obtained, the judgment result is more accurate and reliable, device misoperation is effectively prevented, and compared with the traditional device, the technical scheme hardly increases hardware cost, the traditional analog-digital conversion module is not required to be improved or changed, the protection action speed is not influenced, and the protection misoperation can be reliably prevented, so that the defect of misoperation under the condition that the circuit low load exists in the passive protection device using the unipolar AD is overcome by adopting a low-cost scheme on the premise of not reducing the device speed.
In one embodiment, a monitoring module of a passive protection device includes a part of or the whole structure of the following embodiments; that is, the monitoring module of the passive protection device includes some or all of the following technical features. In one embodiment, a monitoring module for a passive protection device includes: the direct current bias voltage processing module is connected with the circuit; on one hand, the DC bias voltage processing module is used for processing the data acquisition of the AC signals input into the unipolar analog-to-digital conversion module as one path of AC signals, and on the other hand, the full-wave rectification processing module is used for processing the data acquisition of the AC signals input into the unipolar analog-to-digital conversion module as one path of DC signals, so that more accurate judgment conditions can be obtained, and the judgment result is more accurate and reliable.
In one embodiment, as shown in fig. 4, a monitoring module of a passive protection device includes a connection line 100, a dc bias voltage processing module 200, and a full-wave rectification processing module 300; the first end 101 of the connection line 100 is used for inputting an alternating current, and the second end 102 of the connection line is respectively connected to the dc bias voltage processing module 200 and the full-wave rectification processing module 300; the output end 201 of the dc bias voltage processing module 200 is used for connecting a first input end of a unipolar analog-to-digital conversion module of the passive protection device; the output end 301 of the full-wave rectification processing module 300 is used for connecting a second input end of the unipolar analog-to-digital conversion module of the passive protection device.
In one embodiment, the first end of the connection line is used for inputting alternating current; further, in one embodiment, the first end of the connection line is provided with a connection terminal for inputting an alternating current. Namely, a monitoring module of a passive protection device, comprising: the direct current bias voltage processing module is connected with the circuit; the first end of the connecting line is used for inputting alternating current, wherein a connecting terminal is arranged at the first end of the connecting line and used for inputting the alternating current; the second end of the connecting circuit is respectively connected with the direct current bias voltage processing module and the full-wave rectification processing module; the output end of the direct current bias voltage processing module is used for being connected with a first input end of a unipolar analog-to-digital conversion module of the passive protection device; the output end of the full-wave rectification processing module is used for being connected with the second input end of the unipolar analog-to-digital conversion module of the passive protection device. The rest of the examples are analogized. Further, in one embodiment, the connection terminal clamps a current sampling position connected to the passive protection device; or the connecting terminal is in threaded connection with a current sampling position of the passive protection device and is used for inputting alternating current.
In one embodiment, the second end of the connection line is respectively connected to the dc bias voltage processing module and the full-wave rectification processing module; further, in one embodiment, the second end of the connection line has two branch lines, one branch line is connected to the dc bias voltage processing module, and the other branch line is connected to the full-wave rectification processing module; the design is favorable for dividing the alternating current into two paths to be respectively processed. Further, in one embodiment, the connection line is designed as a small box having an input terminal for inputting ac current as the first end, the dc bias voltage processing module and the full-wave rectification processing module are both disposed in the small box and are respectively connected to the second end, and the dc bias voltage processing module and the full-wave rectification processing module are respectively connected to the first input terminal and the second input terminal of the unipolar analog-to-digital conversion module of the passive protection device from the small box outlet connector. In one embodiment, the connection line has a box structure having an input terminal to which an alternating current is input as the first end, the direct current bias voltage processing module and the full wave rectification processing module are both arranged in the box body structure, the direct current bias voltage processing module and the full wave rectification processing module are respectively connected with the second end, the box body structure is provided with a first leading-out connector and a second leading-out connector, the output end of the direct current bias voltage processing module is connected with the first leading-out connector of the box body structure, the first lead-out connector is used for connecting a first input end of a unipolar analog-to-digital conversion module of the passive protection device, the output end of the full-wave rectification processing module is connected with the second leading-out joint of the box body structure, the second leading-out connector is used for connecting a second input end of the unipolar analog-to-digital conversion module of the passive protection device. The design is favorable for manufacturing the monitoring module into a single complete product, realizes the modular design of the components, overcomes the difficulties of multiple circuits, troublesome connection and difficult training in the traditional design, is convenient for connection, is convenient for sale and storage for standby, is greatly favored in trial production, hardly increases the hardware cost compared with the traditional device, does not need to improve or transform the traditional analog-digital conversion module, and can reliably prevent protection misoperation.
In one embodiment, the dc bias voltage processing module includes a dc bias circuit or other circuit for processing a dc bias voltage. In one embodiment, the output end of the dc bias voltage processing module is used for connecting a first input end of a unipolar analog-to-digital conversion module of a passive protection device; the design is favorable for acquiring data of one path of alternating current signals. In one embodiment, the monitoring module further includes a current fundamental wave effective value calculation module, and the current fundamental wave effective value calculation module is used for being connected with the output end of the unipolar analog-to-digital conversion module and calculating the current fundamental wave effective value according to the alternating current sampling value sequence. By the design, the effective value of the current fundamental wave can be conveniently obtained and used as an important reference index for judging whether the fault occurs or not.
Further, in one embodiment, the full-wave rectification processing module includes a bridge rectifier circuit or other ac-dc conversion circuit. Further, in one embodiment, the full-wave rectification processing module includes a bridge rectification filter circuit. As shown in fig. 5, for the unipolar analog-to-digital conversion module AD of the passive protection device, there are two inputs, the first input is an ac AD input signal, the second input is a dc AD input signal, and the full-wave rectification processing module is a bridge rectifier circuit. In one embodiment, the output end of the full-wave rectification processing module is used for connecting a second input end of the unipolar analog-to-digital conversion module of the passive protection device. The design is favorable for acquiring data of one path of direct current signals. In one embodiment, the monitoring module further includes a current true value calculation module, and the current true value calculation module is configured to be connected to the output end of the unipolar analog-to-digital conversion module, and calculate a current true value according to the dc sampling value sequence. By the design, the current true value can be conveniently obtained and used as another important reference index for judging whether the fault occurs; particularly, the fault can be accurately judged by being used together with the effective value of the current fundamental wave, and the false alarm is avoided. Further, in one embodiment, the monitoring module further includes a current fundamental wave effective value calculation module, where the current fundamental wave effective value calculation module is used to connect the first output end of the unipolar analog-to-digital conversion module and calculate a current fundamental wave effective value according to the sequence of alternating current sampling values; the monitoring module further comprises a current true value calculation module, and the current true value calculation module is used for being connected with the second output end of the unipolar analog-to-digital conversion module and calculating a current true value according to the direct current sampling value sequence. According to the design, on one hand, the DC bias voltage processing module is used for processing data acquisition of an AC signal input to the unipolar analog-to-digital conversion module as a path of AC signal, on the other hand, the full-wave rectification processing module is used for processing data acquisition of a DC signal input to the unipolar analog-to-digital conversion module as a path of AC current, so that more accurate judgment conditions can be obtained, and the judgment result is more accurate and reliable; moreover, the cost increased by the design is extremely low or negligible compared with a passive protection device, and the design is particularly suitable for being used in a low-cost scheme.
In one embodiment, the monitoring module further includes a determining module, the determining module is respectively connected to the current fundamental wave effective value calculating module and the current true value calculating module, and the determining module is configured to determine that a fault occurs when the current fundamental wave effective value exceeds a preset first threshold range and the current true value exceeds a preset second threshold range. In one embodiment, the preset first threshold range includes a first threshold and an upper and lower fluctuation range thereof; in one embodiment, the first threshold and the fluctuation range of the first threshold are set or adjusted according to historical experience or actual conditions. In one embodiment, the preset second threshold range includes a second threshold and an upper and lower fluctuation range thereof; in one embodiment, the second threshold and the fluctuation range of the second threshold are set or adjusted according to historical experience or actual conditions. Further, in one embodiment, the determining module is further configured to be connected to a unipolar analog-to-digital conversion module of the passive protection device, for example, the determining module is further configured to be connected to an output terminal of the unipolar analog-to-digital conversion module of the passive protection device. According to the design, on one hand, the fault is determined to occur only when the two paths of judgment are abnormal through the judgment module, compared with the traditional judgment mode, the method is more accurate and effective, the structure is simple, the realization is convenient, and the protection misoperation can be reliably prevented; on the other hand, the processing mode utilizes the spare channel of the unipolar analog-to-digital conversion module of the passive protection device, does not need to add extra processing equipment, has very high calculation efficiency, does not influence the protection action speed, and can effectively give out a judgment result in time. It should be noted that, in the low-cost solution, the four indexes of the cost, effectiveness, usability and stability of the product structure are very important, on one hand, because of the large amount of use, on the other hand, because the unipolar analog-to-digital conversion module of the passive protection device used by itself is adopted for reducing the cost, on the premise that the three indexes of effectiveness, usability and stability are close, the cost is the most critical acceptance index, and in the present application, on the premise that the effectiveness is ensured, from the perspective of simplifying the structure, the easy-to-use, stable and cheap product is attempted to be made.
In one embodiment, the monitoring module further includes a control module, the control module is connected to the judging module, and the control module is further configured to be connected to a protection component of the passive protection device; the control module is used for controlling the protection component to protect when the fault is determined to occur. In one embodiment, the monitoring module further includes a judging module, the judging module is respectively connected to the current fundamental wave effective value calculating module and the current true value calculating module, and the judging module is configured to determine that a fault occurs when the current fundamental wave effective value exceeds a preset first threshold range and the current true value exceeds a preset second threshold range; the monitoring module further comprises a control module, the control module is connected with the judging module, and the control module is further used for being connected with a protection component of the passive protection device; the control module is used for controlling the protection component to protect when the fault is determined to occur. Further, in one embodiment, the control module is integrated with the determination module. The design is applied to a passive protection device, and through the modulus reference voltage of the monitoring device, on one hand, the analog reference voltage is input into the AD 1 st channel in an alternating current mode for collection, and on the other hand, the analog reference voltage is input into the AD 2 nd channel in a direct current mode for collection, so that the method is favorable for obtaining more accurate judgment conditions, judging more accurately and reliably without influencing the protection action speed, and is favorable for being matched with the passive protection device to take effective protection measures such as tripping and the like.
In one embodiment, the monitoring module further comprises an alarm module, the alarm module is connected with the judging module, and the alarm module is used for sending out an alarm signal when a fault is determined. In one embodiment, the monitoring module further includes a judging module, the judging module is respectively connected to the current fundamental wave effective value calculating module and the current true value calculating module, and the judging module is configured to determine that a fault occurs when the current fundamental wave effective value exceeds a preset first threshold range and the current true value exceeds a preset second threshold range; and the monitoring module also comprises an alarm module, the alarm module is connected with the judging module, and the alarm module is used for sending out an alarm signal when the fault is determined. Further, in one embodiment, the alarm module is configured to send an alarm signal to the target terminal and/or send an alarm signal to the audio equipment when the fault is determined. Therefore, managers can know the occurrence of problems at the first time, and the method is favorable for timely and efficiently processing faults and recovering normal operation. Further, in one embodiment, the alarm module is linked with the control module, and is configured to control the protection component to protect and control the alarm module to send an alarm signal when a fault is determined. Or the alarm module is linked with the judgment module, and the judgment module is used for controlling the alarm module to send out an alarm signal when a fault is determined. The design is favorable for realizing accurate, timely and efficient alarm effect under the premise of preventing the device from misoperation, almost has no time delay, and does not generate misinformation.
Further, in one embodiment, the dc bias voltage processing module is configured to implement unipolar processing on the input ac current by using a dc bias voltage, and the processed amount is input to a first input end of a unipolar analog-to-digital conversion module of the passive protection device, that is, the unipolar processing on the ac current is implemented by using the dc bias voltage, and the processed amount is input to the AD 1 st channel for collection; the current fundamental wave effective value calculating module calculates a current fundamental wave effective value Ir in the following mode according to an alternating current sampling value sequence:
Ir＝DFT1(sampac (n)); wherein, sampAC (n) is an alternating current sampling value sequence, DFT is Fourier decomposition with frequency tracking, and Ir is a fundamental wave effective value corresponding to an alternating current.
Further, in one embodiment, the full-wave rectification processing module is configured to perform full-wave rectification on the ac current, and the rectified quantity is input to the second input end of the unipolar analog-to-digital conversion module of the passive protection device, that is, the full-wave rectification mode is adopted to realize dc conversion on the ac current, and the rectified quantity is input to the AD 2 nd channel for collection; the current true virtual value calculation module calculates a current true virtual value Im by adopting the following mode according to the direct current sampling value sequence:
the sampling value sequence is a sequence of dc sampling values, and Im is a true effective value corresponding to the dc quantity, i.e., a true effective value, which may also be referred to as a true effective value.
According to the design, on one hand, Ir is utilized for protection logic judgment; and on the other hand, the start judgment is carried out by utilizing Im through designing protection start logic. The judgment module can adopt or refer to the traditional judgment logic to judge the Ir.
Further, in one embodiment, the judging module judges the start of Im in the following manner:
wherein: im is the true effective value of the corresponding direct current quantity, Iset is the overcurrent protection fixed value, and Startup is the device starting mark.
In this way, when the protection logic and the starting element (startup) act simultaneously, the monitoring module sends a trip command and records a trip event through the control module or the alarm module, so as to prevent misoperation.
In one embodiment, a method for monitoring a passive protection device includes the steps of: inputting alternating current; the DC bias voltage processing module is used for realizing the unipolar processing of the AC current and inputting the unipolar processing of the AC current to a first input end of a unipolar analog-to-digital conversion module of the passive protection device; and the full-wave rectification processing module is adopted to realize the full-wave rectification processing of the alternating current and input the alternating current into a second input end of the unipolar analog-to-digital conversion module of the passive protection device. In one embodiment, the monitoring method is implemented by using the monitoring module in any one of the above embodiments. The design is beneficial to effectively preventing the device from misoperation, the increased cost is extremely low or negligible compared with a passive protection device, and the passive protection device is particularly suitable for being used in a low-cost scheme.
In one embodiment, the monitoring method further comprises the steps of: calculating a current fundamental wave effective value according to the alternating current sampling value sequence, and calculating a current true value according to the direct current sampling value sequence; and determining that a fault occurs when the effective value of the current fundamental wave exceeds a preset first threshold range and the effective value of the current exceeds a preset second threshold range. In one embodiment, the monitoring method further comprises the steps of: when the fault is determined, controlling a protection component of the passive protection device to protect; in one embodiment, the monitoring method further comprises the steps of: and when the fault is determined to occur, sending out an alarm signal. In one embodiment, the monitoring method further comprises the steps of: when the fault is determined, controlling a protection component of the passive protection device to protect; and sending out an alarm signal. Further, in one embodiment, a remote alarm signal is issued. In one embodiment, a remote alert signal is issued to the target terminal.
In one embodiment, the passive protection device is realized by adopting the monitoring method of any embodiment and/or is provided with the monitoring module of any embodiment.
According to the embodiments of the application, the direct current power rectified by the alternating current is innovatively utilized to enter the AD channel, the direct current power does not need bias voltage when entering the AD channel and is not influenced by power supply fluctuation, the AD channel with the bias voltage is innovatively reserved, and the measurement accuracy of the device is ensured; the rectified channel is only used for starting the device, so that the difficulty of research and development of the device is reduced; therefore, when the power supply is unstable, the starting element is not influenced by the fluctuation of the bias voltage, and the protection misoperation can be effectively prevented; furthermore, when a fault occurs, the starting element and the protection logic judgment module can act rapidly, so that the protection action speed is ensured; the number of built-in AD channels is large, so that the cost is hardly increased by adding a rectified fault starting detection channel; compared with the traditional scheme, the method has the advantages of less modification content of software and hardware, good compatibility, low research and development cost and low use cost.
It should be noted that other embodiments of the present application further include a passive protection device, a monitoring module and a monitoring method thereof, which are formed by combining technical features of the above embodiments with each other.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.
Claims (11)
1. A monitoring module for a passive protection device, comprising: the direct current bias voltage processing module is connected with the circuit;
the first end of the connecting line is used for inputting alternating current;
the second end of the connecting circuit is respectively connected with the direct current bias voltage processing module and the full-wave rectification processing module;
the output end of the direct current bias voltage processing module is used for being connected with a first input end of a unipolar analog-to-digital conversion module of the passive protection device;
the output end of the full-wave rectification processing module is used for being connected with a second input end of the unipolar analog-to-digital conversion module of the passive protection device;
the monitoring module also comprises a current fundamental wave effective value calculation module, and the current fundamental wave effective value calculation module is used for connecting the output end of the unipolar analog-to-digital conversion module and calculating a current fundamental wave effective value according to an alternating current sampling value sequence;
the monitoring module also comprises a current true value calculation module which is used for connecting the output end of the unipolar analog-to-digital conversion module and calculating a current true value according to the direct current sampling value sequence;
the monitoring module further comprises a judging module, the judging module is respectively connected with the current fundamental wave effective value calculating module and the current true value calculating module, and the judging module is used for determining that a fault occurs when the current fundamental wave effective value exceeds a preset first threshold range and the current true value exceeds a preset second threshold range.
2. The monitoring module according to claim 1, characterized in that the first end of the connection line is provided with a connection terminal for the input of an alternating current.
3. The monitoring module of claim 2, wherein the connection terminal clamps a current sampling location connected to the passive protection device; or the connecting terminal is in threaded connection with a current sampling position of the passive protection device and is used for inputting alternating current.
4. The monitoring module of claim 1, wherein the second end of the connection line has two branch lines, one branch line being connected to the dc bias voltage processing module and the other branch line being connected to the full wave rectification processing module.
5. The monitoring module of claim 1, further comprising a control module, wherein the control module is connected to the determining module, and the control module is further configured to be connected to a protection component of the passive protection device; the control module is used for controlling the protection component to protect when the fault is determined to occur.
6. The monitoring module according to claim 1 or 5, further comprising an alarm module, wherein the alarm module is connected to the judging module, and the alarm module is configured to send an alarm signal when a fault is determined.
7. A method of monitoring a passive protection device, comprising the steps of:
inputting alternating current;
the DC bias voltage processing module is used for realizing the unipolar processing of the AC current and inputting the unipolar processing of the AC current to a first input end of a unipolar analog-to-digital conversion module of the passive protection device;
the full-wave rectification processing module is adopted to realize the full-wave rectification processing of the alternating current, and the alternating current is input into a second input end of the unipolar analog-to-digital conversion module of the passive protection device;
calculating a current fundamental wave effective value according to the alternating current sampling value sequence, and calculating a current true value according to the direct current sampling value sequence;
and determining that a fault occurs when the effective value of the current fundamental wave exceeds a preset first threshold range and the effective value of the current exceeds a preset second threshold range.
8. The monitoring method of claim 7, further comprising the steps of: and when the fault is determined, controlling a protection component of the passive protection device to protect.
9. The monitoring method of claim 7, further comprising the steps of: and sending out an alarm signal.
10. The monitoring method of claim 7, further comprising the steps of: and when the fault is determined, controlling a protection component of the passive protection device to protect, and sending out an alarm signal.
11. A passive protection device, characterized in that it is implemented using the monitoring method of any one of claims 7 to 10 and/or has the monitoring module of any one of claims 1 to 6.
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