CN115840099A - Arc fault generating device and control method - Google Patents

Abstract

An arc fault generating device and a control method thereof are provided, wherein the device comprises: the arc generator comprises a first electrode, a second electrode and a voltage sensor, wherein the voltage sensor is used for detecting voltage between the first electrode and the second electrode, the current sensor is used for detecting current of the first electrode or the second electrode, the control unit is used for receiving signals of the voltage sensor and the current sensor, the control unit is further used for judging a contact state between the first electrode and the second electrode according to the signals of the voltage sensor, when the first electrode and the second electrode are judged to be in stable contact, the arc time is judged according to detection signals of the voltage and current detection unit, and an interpolar voltage allowable value of the arc generator is adjusted according to the arc time. The technical effect of better simulating the fault arc can be achieved by the scheme.

Description

Arc fault generating device and control method

Technical Field

The present invention relates to a method for generating an arc fault, and more particularly, to a device and a method for optimally controlling an arc fault logic.

Background

In a building, an electric arc fault is a fault type with high danger, high concealment and high uncertainty, if the fault type cannot be eliminated in time, an electric fire can be caused, and the production and life are threatened, especially if a high-rise building generates the electric fire, serious economic loss can be caused. In order to prevent such electrical fire, it is one of the common methods to add corresponding protection products. Arc fault protection products mainly include arc fault detectors and arc fault circuit breakers, one of the key technologies of which is arc fault detection. Therefore, fault arc tests are performed in both the development stage and the factory inspection stage of the product, and the national standard GB 14287.4 "fourth part of electrical fire monitoring system: the tests are respectively specified by a fault arc detector and GB/T31143 general requirements of arc fault protection-protection electric appliances AFDD, wherein the tests comprise a fault arc simulation method and a fault arc maximum arcing time requirement in different test currents. An arc fault generating device is one of the devices required for fault arc simulation. The arc fault generating device consists of a carbon electrode and a copper electrode, wherein one electrode is static, the other electrode can move, and when the two electrodes are in contact and pass through current, the moving electrode is transversely adjusted to be separated from the static electrode until an arc is generated. The separation distance and the arc discharge speed of the two electrodes directly influence the simulation effect of the fault arc; the invention aims to research an arc fault generator for detecting an arc fault protection electric appliance, and improve the structure and the control method of an arc fault generating device, thereby improving the success rate of fault arc simulation.

Disclosure of Invention

Therefore, a new arc fault generating device and a control method are needed to achieve the technical effect of rapidly judging the arcing time.

To achieve the above object, the inventors provide an arc fault generating apparatus comprising:

the arc generator comprises a first electrode, a second electrode and a voltage sensor, wherein the voltage sensor is used for detecting voltage between the first electrode and the second electrode, the current sensor is used for detecting current of the first electrode or the second electrode, the control unit is used for receiving signals of the voltage sensor and the current sensor, the control unit is further used for judging a contact state between the first electrode and the second electrode according to the signals of the voltage sensor, when the first electrode and the second electrode are judged to be in stable contact, arc generation simulation is carried out, arc burning time is judged according to detection signals of the voltage sensor and the current sensor, and an interpolar voltage allowable value of the arc generator is adjusted according to the arc burning time.

In some embodiments of the present application, the control unit is configured to calculate: calculating a period voltage effective value U from the voltage U detected by the voltage sensor, satisfying 80% _s U > 20V, and the ratio of contact voltage to line current is greater than contact resistance R _jc As the duration of the state of finite value of U _s Is the supply voltage.

In some embodiments of the present application, the system further includes an arc fault protector testing circuit, the arc fault protector testing circuit is configured to access the arc generator when the contact state of the first electrode and the second electrode is contact, the control unit is further configured to enter an arc generation simulation phase when the contact state of the first electrode and the second electrode is stable contact, and execute a closed-loop control mode of PID, where the closed-loop control mode includes a voltage adjusting ring, a displacement ring, and a speed ring, the voltage adjusting ring is an outer ring, and uses a sustained arcing time deviation as an input, and the voltage regulator outputs a given voltage value; the middle ring is a displacement ring, the voltage deviation is used as an input quantity, and the displacement regulator outputs displacement variation quantity; the inner ring is a speed ring, takes the displacement deviation as input and is used for adjusting the running speed of the stepping motor.

In some embodiments of the present application, the arc fault protector test circuit is further connected to a test circuit state detection module and a test circuit control module.

In some embodiments of the present application, further comprising: the contact state detection circuit comprises a current-limiting resistor R, a direct-current power supply module and a contactor KM1, the contact state detection circuit is used for being out of contact with the arc generator when the first electrode and the second electrode are judged to be in a stable contact state, the control unit is further used for executing a detection closed-loop control mode when the contact state detection circuit is in contact with the arc generator, the detection closed-loop control mode is that voltage variation is calculated to serve as feedback quantity, and the relative movement speed of the two electrodes is adjusted until the voltage between the two electrodes keeps unchanged.

An arc fault occurrence control method is suitable for the arc fault occurrence device and comprises the steps that a voltage sensor and a current sensor respectively detect the voltage and the current between a first electrode and a second electrode, a control unit receives signals of the voltage sensor and the current sensor, judges the contact state between the first electrode and the second electrode according to the detected signals of the voltage sensor, performs arc generation simulation when the first electrode and the second electrode are judged to be stably contacted, judges the arc burning time according to the detected signals of the voltage sensor and the current sensor, and adjusts the interpolar voltage allowable value of an arc generator according to the arc burning time.

In some embodiments of the present application, further comprising the step of the control unit calculating a period voltage effective value U from the voltage U detected by the voltage sensor, calculating 80% _s U > 20V, and the ratio of the contact voltage to the line current is greater than the contact resistance R _jc As the arc time, U _s Is the supply voltage.

In some embodiments of the present application, an arc generation simulation phase is entered when the contact state of the first electrode and the second electrode is stable contact, and the method further includes a closed loop control step of PID, including a voltage regulation loop, a displacement loop, and a speed loop, where the voltage regulation loop is an outer loop and takes the sustained arcing time deviation as an input, and the voltage regulator outputs a given voltage value; the middle ring is a displacement ring, the voltage deviation is used as an input quantity, and the displacement regulator outputs displacement variation quantity; the inner ring is a speed ring, takes the displacement deviation as input and is used for adjusting the running speed of the stepping motor.

In some embodiments of the present application, the apparatus further comprises: the arc fault protector testing circuit is connected with the testing circuit state detection module and the testing circuit control module; the contact state detection circuit comprises a current limiting resistor R, a direct-current power supply module and a contactor KM1, and the contact state circuit control and monitoring module is used for controlling and detecting the working state of the contactor KM 1; the control method further comprises the step of executing a detection closed-loop control mode when the contact state detection circuit is in contact with the arc generator, wherein the detection closed-loop control mode is to calculate the voltage variation as a feedback quantity and adjust the relative movement speed of the two electrodes until the voltage between the two electrodes is kept unchanged.

In some embodiments of the present application, the control unit controls the contact state detection circuit to be out of contact with the arc generator when it is determined that the first electrode and the second electrode are stably in contact.

Different from the prior art, the technical scheme judges the arcing time by designing a voltage threshold detection method and controls the voltage of the electrode through the arcing time feedback, so that the technical effect of better simulating the fault arc is achieved.

Drawings

FIG. 1 is a schematic diagram of an arc generator according to an embodiment of the present invention;

FIG. 2 is a diagram of an arc fault generating apparatus according to another embodiment of the present invention;

FIG. 3 is a schematic diagram of PID closed loop control according to an embodiment of the present invention

FIG. 4 is a diagram of a method for controlling arc fault occurrence in accordance with an embodiment of the present invention;

fig. 5 is a flowchart illustrating operation of an arc fault generating apparatus according to an embodiment of the present invention.

Drawings

1. A first electrode; 2. a second electrode; 3. a stepping motor; 4. fixing a bracket; 5. a sliding module; 6. an electrode mounting table; 7. fastening screws; 8. a screw rod; 91. a photoelectric switch sensor; 92. a photoelectric switch sensor; 93. a shading sheet.

Detailed Description

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or related to other embodiments specifically defined. In principle, in the present application, the technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution as long as there is no technical contradiction or conflict.

Unless defined otherwise, technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the use of relational terms herein is intended only to describe particular embodiments and is not intended to limit the present application.

In the description of the present application, the term "and/or" is a expression for describing a logical relationship between objects, meaning that three relationships may exist, for example a and/or B, meaning: there are three cases of A, B, and both A and B. In addition, the character "/" herein generally indicates that the former and latter associated objects are in a logical relationship of "or".

In this application, terms such as "first" and "second" are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

Without further limitation, in this application, the use of "including," "comprising," "having," or other similar expressions in phrases and expressions of "including," "comprising," or "having," is intended to cover a non-exclusive inclusion, and such expressions do not exclude the presence of additional elements in a process, method, or article that includes the recited elements, such that a process, method, or article that includes a list of elements may include not only those elements but also other elements not expressly listed or inherent to such process, method, or article.

As is understood in the examination of the guidelines, the terms "greater than", "less than", "more than" and the like in this application are to be understood as excluding the number; the expressions "above", "below", "within" and the like are understood to include the present numbers. In addition, in the description of the embodiments of the present application, "a plurality" means two or more (including two), and expressions related to "a plurality" similar thereto are also understood, for example, "a plurality of groups", "a plurality of times", and the like, unless specifically defined otherwise.

In the description of the embodiments of the present application, spatially relative expressions such as "central," "longitudinal," "lateral," "length," "width," "thickness," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used, and the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the specific embodiments or drawings and are only for convenience of describing the specific embodiments of the present application or for the convenience of the reader, and do not indicate or imply that the device or component in question must have a specific position, a specific orientation, or be constructed or operated in a specific orientation and therefore should not be construed as limiting the embodiments of the present application.

Unless specifically stated or limited otherwise, the terms "mounted," "connected," "secured," and "disposed" used in the description of the embodiments of the present application are to be construed broadly. For example, the connection can be a fixed connection, a detachable connection, or an integrated arrangement; it can be a mechanical connection, an electrical connection, or a communication connection; they may be directly connected or indirectly connected through an intermediate; which may be communication within two elements or an interaction of two elements. Specific meanings of the above terms in the embodiments of the present application can be understood by those skilled in the art to which the present application pertains in accordance with specific situations.

Referring to fig. 1, an embodiment of an arc fault generating apparatus includes: the arc generator comprises a first electrode 1, a second electrode 2 and a voltage sensor, wherein the voltage sensor is used for detecting voltage between the first electrode and the second electrode, the current sensor is used for detecting current of the first electrode or the second electrode, the control unit is used for receiving signals of the voltage sensor and the current sensor, the control unit is further used for judging a contact state between the first electrode and the second electrode according to the signals of the voltage sensor, when the first electrode and the second electrode are judged to be in stable contact, arc generation simulation is carried out, arc burning time is judged according to detection signals of the voltage sensor and the current sensor, and an interpolar voltage allowable value of the arc generator is adjusted according to the arc burning time. In the embodiment shown in fig. 1, the data acquisition unit may include 1 voltage sensor, 1 current sensor. The voltage sensor is used for detecting voltages at two ends of the electrode in the contact process and detecting a voltage u between the two electrodes before and after a fault arc occurs in an arc fault experiment; the current sensor is used for detecting the current i passing through the electrode before and after the fault arc occurs. When the movable electrode transversely moves towards the fixed electrode and contacts, the voltage sensor detects the voltages at two ends of the electrode in real time, and when the detection value of the voltage sensor is stable, the first electrode and the second electrode can be judged to be stably contacted. At the moment, the arcing time is judged according to the voltage and the current, and the voltage is subjected to closed-loop modulation according to the arcing time, so that the generated arc can meet the requirement and can be better used for simulating the fault arc. Compared with the traditional scheme of designing the pressure sensor to detect the pressure between the first electrode and the second electrode, the scheme can omit the judgment of the initial state and the final state of electrode contact, and avoid the situation that after multiple times of use, the copper electrode possibly penetrates through the surface of the carbon electrode, and the sensing element of the pressure sensor is pressed more tightly and possibly damaged when the measuring range of the pressure sensor is exceeded. The scheme of using the voltage sensor for judgment has the advantage that even if the last actuation is not completely reset, the two electrodes can be directly used for judgment when in an unstable state of just contacting. The follow-up reentry arcing time is judged, the allowable value of interpolar voltage is judged and adjusted through the arcing time, the interpolar voltage allowable value is a range, the interpolar voltage allowable value is influenced by the electrode distance under the condition that an input power supply is stable, limitation is made to the interpolar voltage allowable value, the interpolar voltage allowable value can help an arcing stage system to stably generate electric arcs, the device is prevented from being fed back and adjusted to fail to cause arc hours, and the practicability of the arc fault generation device can be effectively improved.

In some embodiments of the present application, the control unit is configured to calculate: calculating a period voltage effective value U from the voltage U detected by the voltage sensor, satisfying 80% _s U > 20V, and the ratio of contact voltage to line current is greater than contact resistance R _jc As the arc time, U _s Is the supply voltage. The judgment of the arcing time can quickly judge whether an effective electric arc exists between the two electrodes. In a specific embodiment, the determination of the arcing time may be obtained by the control unit running an arcing time calculation program, thereby implementing the identification of the fault arc. Combining the electrical characteristics of the fault arc, processing the voltage between the two electrodes and the electrode circulating current, and obtaining the period voltage effective value U and the resistance R between the two electrodes through calculation _h And the time is used as the basis for judging the arcing time and the continuous arcing time. Before arc discharge, the two electrodes are contacted, and the effective value U of the periodic voltage at the moment is detected and recorded as the contact voltage U of the two electrodes _jc The line current is the test current. At this time, the arc resistance is not present but only the contact resistance is present between the electrodes, and the average value R of the contact resistance is calculated from the ratio between the contact voltage and the test current _jc . When an electric arc is generated, electric arc voltage and electric arc resistance exist between the two electrodes, and technicians conclude that the voltage between the two electrodes is generally more than 20V and lower than the power supply voltage in the process of arc discharge of the electrodes through multiple tests; when the two electrodes are completely separated or the arc is intermittently extinguished and can not be reignited in the separation process, the effective value of the periodic voltage is equal to the power supply voltage U _s At this time, the current flowing through the electrodes is 0, and the resistance between the electrodes is infinite. The criteria for determining the presence of an arc may be set as: 80% of U _s > U > 20V and R _h Is one greater than the contact resistance R _jc Is determined to be present between the two electrodes. 80% of U _s The threshold value can be adjusted to 70% -90% according to the requirement, the starting and stopping time of the arc is recorded, and the continuous arc time t of the arc is recorded _arc . The method is simple in calculation, does not have a complex operation process, can ensure the real-time performance of device control, and improves the experiment efficiency。

In some further embodiments of the present application, the apparatus further includes an arc fault protector testing circuit, the arc fault protector testing circuit is configured to access the arc generator when the contact state of the first electrode and the second electrode is contact, and the control unit is further configured to enter an arc generation simulation phase when the contact state of the first electrode and the second electrode is stable contact, and execute a closed-loop control mode of PID, where in some embodiments as shown in fig. 2, PID control logic suitable for the apparatus is shown. Specifically, the control unit is further configured to execute a closed-loop control mode of PID, including a voltage regulation loop, a displacement loop, and a speed loop, where the voltage regulation loop is an outer loop and takes the sustained arcing time deviation as an input, and the voltage regulator outputs a given voltage value; the middle ring is a displacement ring, the voltage deviation is used as an input quantity, and the displacement regulator outputs displacement variation quantity; the inner ring is a speed ring, takes the displacement deviation as input and is used for adjusting the running speed of the stepping motor. The device comprises a voltage regulator, a displacement regulator and a speed regulator, wherein the three regulators can be virtual program modules in the control unit or entity devices. Taking a voltage regulator, a displacement regulator and a speed regulator as virtual program modules respectively as examples, the voltage regulator can regulate the contact of the electrodes with the arc generator, the control unit is further configured to execute a detection closed-loop control mode when the contact state detection circuit is in contact with the arc generator, and the detection closed-loop control mode is that voltage variation is calculated as feedback quantity, and the speed of relative movement of the two electrodes is regulated until the voltage between the two electrodes is kept unchanged. The principle for detecting the closed-loop control mode here is as follows: when the movable electrode transversely moves towards the fixed electrode and contacts, the voltage sensor detects the voltages at two ends of the electrode in real time, and the voltages are used as feedback quantity to perform closed-loop modulation on the rotation speed of the motor in the contact process, so that stable electric contact between the two electrodes is ensured, and impact on the fixed support caused by impact force at the moment of contact is avoided. Meanwhile, under the condition that the initial state of the initial pressure value of the pressure sensor in each experimental process is not completely consistent, the contact pressure criterion is difficult to guarantee; in addition, if the movable electrode is not separated from the fixed electrode due to the abnormality of the previous experiment, the initial pressure detected by the pressure sensor is actually the pressure when the electrodes are in contact, and then the difference between the initial pressure and the real-time pressure is used as the criterion for the contact between the two electrodes, so that the misjudgment can occur, the copper electrode can possibly penetrate through the surface of the carbon electrode, and the sensing element of the pressure sensor can be pressed more tightly, and the sensing element can be damaged when the measuring range of the sensing element is exceeded. The skilled person of the present application has found the above problem by designing the value of the voltage signal to determine what state of non-contact, preliminary contact and stable contact the electrode is in. If the voltage is in a non-contact state, the voltage between the electrodes is 0, and in a preliminary contact state, the voltage between the electrodes is small, but the voltage variation is large, and when the voltage is in a stable contact state, the voltage between the electrodes is in a stable value. In the process of testing experiment of the arc fault protection electric appliance, the voltage detected by the voltage sensor and the current detected by the current sensor are transmitted to the computer through the analog input channel of the multifunctional high-speed acquisition card and are read by the data acquisition and control program, the voltage and the current are converted in the monitoring and control device and are reduced into the voltage value and the current value in the actual circuit, and the two parts of waveform data are used as the input of the arithmetic unit to realize the premise of rated calculation of the arcing time and realization of a closed-loop control algorithm.

The arithmetic unit is a part of the monitoring and control unit and is written by LabVIEW software, and mainly comprises closed-loop modulation, an arcing time calculation program and a closed-loop control algorithm program in the contact process. The closed-loop modulation of the contact process takes the voltage between the two electrodes as feedback quantity, when the movable electrode moves towards the direction of the fixed electrode, the monitoring and control device calculates the voltage average value of every 10 sampling points of the collected voltage signal and calculates the voltage average value once and the voltage average value is obtainedRecording the current voltage value and comparing the current voltage value with the working voltage U of the DC voltage source _d Comparing, using the deviation as the criterion for regulating motor speed, updating the frequency of PWM to realize speed regulation until the voltage between two electrodes is lower than U _d And remain substantially stable.

In other embodiments, as shown in fig. 3, the arc fault generating device further comprises a monitoring and control program, which is executed by the computer, the multifunctional high-speed data acquisition card, the data acquisition and arithmetic unit, and the arithmetic unit. The multifunctional high-data acquisition card is arranged on a PCIE interface of a computer and used as an input/output module, and can output a control command and acquire real-time operation information of a real-time device. The model is PCIE1816H, which is provided with an analog signal input/output channel, a digital signal input/output channel and a PWM pulse output channel. The monitoring and control device transmits a speed control command to the power system through a PWM pulse output channel of the multifunctional high-data acquisition card, transmits a direction control command to the power system through a digital signal output channel (DO), and receives operation state information of an actuating mechanism from the data acquisition module through an analog signal input channel (AI), wherein the operation state information comprises voltage waveform data between two electrodes and current waveform data circulating through the electrodes. Meanwhile, a test circuit of the arc fault protection electric appliance and a contact state detection loop are controlled to a test circuit control module and a contact state loop control module through a digital signal output channel (DO); meanwhile, in the working process of the test circuit and the detection loop, the digital signal input channel (DI) is used for detection. The data acquisition and control program is used for realizing acquisition and processing of the running state of the executing mechanism and generating a direction signal and a PWM pulse signal required by the running of the stepping motor. And updating the frequency and the pulse number of the direction signal and the PWM pulse signal in real time according to the displacement variable quantity and the speed variable quantity output by the closed-loop control algorithm program.

As can also be seen in fig. 3, the electrical arc fault protection test circuit is designed using a contactor according to the test standards for the electrical arc fault protection product, including contactor KM2. The control process of all the switches is switched by the monitoring and control device according to a set experimental flow, and the operation process is automatically completed. The test circuit control module utilizes the serial-parallel conversion register to expand DO channels of the data acquisition card, controls the contactor through the optical coupling isolation amplification driving circuit, and can complete control of the operation process of all switches of the test circuit only through three DO channels of the data acquisition card; the test circuit state monitoring module is designed by utilizing a parallel-serial register, the on-off state of an auxiliary contact of the contactor is used as the feedback quantity of the on-off state of a main contact of the contactor, the feedback quantity is connected into a parallel-serial circuit, the working states of all switches are packaged into serial data, the serial data are monitored and received by a controller through three DI channels of a data acquisition card, the monitoring controller receives the state serial data to calculate, and finally the operation information of all switches is identified.

In some embodiments shown in fig. 3, the arc generator includes an actuator, and the specific structure of the actuator is understood with reference to fig. 1, and includes an arc generator and its first electrode 1, second electrode 2, stepping motor 3 fixing bracket 4, sliding module 5, electrode mounting table 6, fastening screw 7, lead screw 8, photoelectric switch sensor 91 and photoelectric switch sensor 92, and light shielding sheet 93. The first electrode 1 can be a static electrode, a carbon electrode is adopted, and the contact surface of the first electrode is a flat end; the second electrode 2 can be a movable electrode made of copper, and the contact surface of the movable electrode is a tip. The stationary electrode is fixedly mounted on an electrode mounting table 6. The movable electrode and the static electrode are detachable parts and can be fixed and detached through the fastening screws 7, and the surface shape and the electrode material of the electrode can be replaced according to the experimental needs. The movable electrode is arranged on a sliding module 81 through a fixed bracket 4, and the sliding module 81 is connected with a motor screw 8 and moves transversely under the driving of a stepping motor. In the initial state, the two electrodes are completely separated, and when the motor 3 rotates, the sliding module 81 is driven to move so as to drive the movable electrode to move transversely, and the movable electrode is contacted with or separated from the fixed electrode. The limiting function module comprises a photoelectric switch sensor 91, a photoelectric switch sensor 92 and a light shielding sheet 93, wherein the photoelectric switch sensors 91 and 92 are U-shaped photoelectric switch sensors, and the light shielding sheet 93 is a hard stainless steel sheet; when the movable electrode moves transversely, when the preset stroke is exceeded, the shading sheet 93 will extend into the groove of the U-shaped photoelectric switch sensor to change the level signal output by the photoelectric switch sensor, and the signal is input into the monitoring and control device through the DI channel of the high-speed data acquisition card to limit the electrode movement, and the PWM pulse is forcibly stopped, so that the motor stops running, and the motor can be driven to run reversely unless the electrode movement direction is changed, thereby protecting the movable electrode movement distance from exceeding the maximum allowable stroke of the device, and causing the damage of mechanical parts.

In order to control the above scheme, in the embodiment shown in fig. 4, an arc fault occurrence control method is further introduced, which is applied to the arc fault occurrence device shown in the above, and further includes steps of S40 detecting a voltage and a current between the first electrode and the second electrode respectively by a voltage sensor and a current sensor, S41 determining a contact state between the first electrode and the second electrode according to a signal of the detected voltage sensor, S42 performing arc generation simulation when it is determined that the first electrode and the second electrode are stably contacted, determining an arc time according to detection signals of the voltage sensor and the current sensor, and adjusting an interelectrode voltage allowable value of the arc generator according to the arc time. According to the scheme, the voltage at two ends of the electrode can be detected in real time through the voltage sensor and is used as a feedback quantity to judge whether the electrode is in a stable contact state. Compared with the traditional scheme that the pressure sensor is designed to be used for detecting the pressure between the first electrode and the second electrode, the method has the advantages that the judgment of the initial state and the final state of electrode contact can be omitted, then the arcing time is judged, and the voltage is subjected to closed-loop modulation according to the arcing time, so that the generated electric arc can meet the requirements, and the method is better used for simulating the fault electric arc.

In some embodiments of the present application, the method further comprises the step of the control unit calculating a period voltage effective value U from the voltage U detected by the voltage sensor, calculating a ratio satisfying 80% _s U > 20V, and the ratio of contact voltage to line current is greater than contact resistance R _jc As the arc time, U _s As a power supplyA voltage. The judgment method is simple in calculation, does not have a complex operation process, can ensure the real-time performance of device control, and improves the experiment efficiency.

In some embodiments of the present application, when the contact state of the first electrode and the second electrode is stable contact, the arc generation simulation phase is entered, and the method further includes a closed loop control step of PID, including a voltage adjusting ring, a displacement ring, and a speed ring, where the voltage adjusting ring is an outer ring, the voltage adjusting ring takes the sustained arcing time deviation as an input, and the voltage regulator outputs a given voltage value; the middle ring is a displacement ring, the voltage deviation is used as an input quantity, and the displacement regulator outputs displacement variation; the inner ring is a speed ring, takes the displacement deviation as input and is used for adjusting the running speed of the stepping motor. By designing the PID closed-loop control, the dynamic control of the generation of the electric arc can be finally realized by controlling the adjustment of the voltage value through the arcing time, controlling the displacement through the voltage deviation and adjusting the rotating speed of the motor through the displacement deviation.

In some embodiments of the present application, the apparatus further comprises: the arc fault protector testing circuit is connected with the testing circuit state detection module and the testing circuit control module; the contact state detection circuit comprises a current limiting resistor R, a direct-current power supply module and a contactor KM1, and the contact state circuit control and monitoring module is used for controlling and detecting the working state of the contactor KM 1; the control method further comprises the step of executing a detection closed-loop control mode when the contact state detection circuit is in contact with the arc generator, wherein the detection closed-loop control mode is to calculate the voltage variation as a feedback quantity and adjust the relative movement speed of the two electrodes until the voltage between the two electrodes is kept unchanged. By means of the scheme design, KM1 can be ensured to be normally put into operation, and the effect of contact state detection is achieved.

In some embodiments of the present application, when it is determined that the first electrode and the second electrode are stably contacted, the control unit controls the contact state detection circuit to be out of contact with the arc generator. The above scheme can actually achieve the function of disconnection after entering a stable contact state.

Referring next to fig. 5, in the embodiment shown in fig. 5, the method begins at step 1: KM1 is closed, when the arc generating device is electrified, the contactor KM1 is closed firstly, KM2 is kept disconnected, and the contact state detection circuit is put into operation.

Step 2: the voltage sensor detects the voltage between the two electrodes, judges whether the electrodes are in contact or not, directly starts an arc fault experiment if the electrodes are in contact, and then turns to the step 5; if not, go to step 2.

And step 3: the stepping motor is controlled to rotate at a higher rotating speed at a given initial speed, so that the movable electrode is driven to transversely move towards the fixed electrode.

And step 3: and in the moving process of the movable electrode, detecting the voltage between the two electrodes in real time, adjusting the rotating speed of the stepping motor in the contact motion process according to a closed-loop modulation control mode of the contact process, and considering that the two electrodes are completely electrically contacted until the voltage between the two electrodes is kept stable.

And 4, step 4: and controlling KM1 to be disconnected, and enabling the contact state detection loop to exit from operation.

And 5: and controlling KM2 to be closed, and putting the arc fault protection electric appliance test circuit into operation. The arc fault protection electric appliance test circuit completes the switching of the corresponding switch according to the established experimental process in the monitoring and control device.

Step 6: the data acquisition unit detects the voltage of the current two electrodes and the current passing through the electrodes in real time, judges whether the current passes through the two electrodes or not and prepares for arc discharge.

And 7: after the two electrodes pass through the current, the movable electrode adjusts the arc gap and the electrode movement speed according to a closed-loop control mode based on the incremental PID, and then arc discharge is started.

And 8: and after the arc discharge ending condition is met, the closed-loop control mode is exited, and the movable electrode quickly returns to the initial position.

And step 9: and (5) powering off the device and finishing the test.

In the contact process closed-loop modulation mode in the step 3, the voltage between the two electrodes is used as a feedback quantity, and when the movable electrode moves towards the direction of the fixed electrode, the monitoring and control device is used for monitoring the collected voltageThe signal calculates the voltage average value of every 10 sampling points and records the voltage average value as the current voltage value, and the current voltage value and the working voltage U of the direct-current voltage source are compared _d And comparing, wherein the deviation value of the two values is used as the input value of a speed regulator, the speed regulator adopts incremental PID for control, when the two electrodes are initially contacted, the deviation between the current voltage and the given voltage is increased, the frequency of the control pulse PWM of the stepping motor is updated, so that the rotating speed of the stepping motor is reduced, the stepping motor continuously moves at a slow speed, and when the average value of the voltage measured at the last two times is kept unchanged, the two electrodes are considered to be contacted.

And 5, establishing a closed-loop control mode based on the incremental PID on the basis of real-time data acquisition, arc time calculation and a closed-loop control algorithm. In the arc discharge process, the current voltage effective value U and the arc resistance are calculated according to the voltage and current signals collected in real time, whether an arc is generated or not is judged according to the voltage change and the arc resistance change, and the continuous arc burning time t is measured and calculated _arc . And simultaneously, measuring and calculating the current electrode spacing according to the output PWM pulse number, and taking the real-time measured and calculated parameters as the feedback quantity of the closed-loop control mode of the incremental PID.

The mathematical model of the incremental PID algorithm is:

Δu(k)＝u(k) -u(k - 1)

in the formula, u (k-1) and u (k) are PID regulator output values at the k-th time. The output of the PID regulator can be known from the PID control principle as follows:

therefore, the number of the first and second electrodes is increased,

Δu(k)＝(K _p go out K _i Go out K _d )e(k) - (K _p Go out 2K _d ) e (K-1) gives K _d e(k - 2)，

e (k), e (k-1) and e (k-2) are respectively deviation values of PID controller input signals at sampling moments of k, k-1 and k-2; k _p ，K _i ，K _d Respectively, proportional coefficient, integral coefficient and differential coefficient of the PID controller.

Movable electrodeWhen starting arc discharge, the required maximum continuous arcing time is taken as the given arcing time t _arc0 The voltage regulator outputs a given voltage U according to the amount of arc time deviation ₀ . The deviation value of the given voltage value and the current voltage effective value U is used as the input of the displacement regulator to update the PWM pulse output number and the motor running direction, control the rotation cycle number of the stepping motor and limit the electrode spacing; the displacement regulator outputs a given amount of electrode spacing. And the deviation value of the given value of the electrode distance output by the displacement regulator and the current electrode distance is used as the input of the displacement regulator and is used for updating the frequency of the PWM pulse so as to control the rotating speed of the motor.

And 6, the conditions for arc discharge ending comprise that the arc duration meets the set maximum arc time limit value and the maximum time allowed by the test of the arc generating device.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrases "comprising 8230; \8230;" or "comprising 8230; \8230;" does not exclude additional elements from existing in a process, method, article, or terminal device that comprises the element. Further, herein, "greater than," "less than," "more than," and the like are understood to exclude the present numbers; the terms "above", "below", "within" and the like are to be understood as including the number.

As will be appreciated by one skilled in the art, the above-described embodiments may be provided as a method, apparatus, or computer program product. These embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. All or part of the steps in the methods according to the embodiments may be implemented by a program instructing associated hardware, where the program may be stored in a storage medium readable by a computer device and used to execute all or part of the steps in the methods according to the embodiments. The computer devices, including but not limited to: personal computers, servers, general-purpose computers, special-purpose computers, network devices, embedded devices, programmable devices, intelligent mobile terminals, intelligent home devices, wearable intelligent devices, vehicle-mounted intelligent devices, and the like; the storage medium includes but is not limited to: RAM, ROM, magnetic disk, magnetic tape, optical disk, flash memory, U disk, removable hard disk, memory card, memory stick, network server storage, network cloud storage, etc.

The various embodiments described above are described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a computer apparatus to produce a machine, such that the instructions, which execute via the processor of the computer apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer device to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer apparatus to cause a series of operational steps to be performed on the computer apparatus to produce a computer implemented process such that the instructions which execute on the computer apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Although the embodiments have been described, other variations and modifications of the embodiments may occur to those skilled in the art once they learn of the basic inventive concepts, so that the above description is only for the embodiments of the present invention, and is not intended to limit the scope of the invention, which is intended to be covered by the present invention.

Claims (10)

1. An arc fault generating device, comprising:

an arc generator comprising a first electrode, a second electrode,

a voltage sensor for detecting a voltage between the first electrode and the second electrode,

a current sensor for detecting a current of the first electrode or the second electrode,

the control unit is used for receiving signals of the voltage sensor and the current sensor, judging the contact state between the first electrode and the second electrode according to the signals of the voltage sensor, carrying out arc generation simulation when the first electrode and the second electrode are judged to be stably contacted, judging arc burning time according to detection signals of the voltage sensor and the current sensor, and adjusting an interpolar voltage allowable value of the arc generator according to the arc burning time.

2. The arc fault occurrence device of claim 1,

the control unit is used for calculating: calculating a period voltage effective value U from the voltage U detected by the voltage sensor, satisfying 80% _s U > 20V, and the ratio of contact voltage to line current is greater than contact resistance R _jc Duration of the state of finite value ofFor arcing time, U _s Is the supply voltage.

3. The arc fault generating device according to claim 1, further comprising an arc fault protector testing circuit, wherein the arc fault protector testing circuit is configured to access the arc generator when the contact state of the first electrode and the second electrode is contact, the control unit is further configured to enter an arc generation simulation phase when the contact state of the first electrode and the second electrode is stable contact, and execute a closed-loop control mode of PID, which includes a voltage adjusting ring, a displacement ring and a speed ring, wherein the voltage adjusting ring is an outer ring, and takes a sustained arcing time deviation as an input, and the voltage regulator outputs a given voltage value; the middle ring is a displacement ring, the voltage deviation is used as an input quantity, and the displacement regulator outputs displacement variation quantity; the inner ring is a speed ring, takes the displacement deviation as input and is used for adjusting the running speed of the stepping motor.

4. The arc fault occurrence apparatus of claim 3, wherein the arc fault protector test circuit is further connected to the test circuit state detection module and the test circuit control module.

5. The arc fault occurrence device of claim 3, further comprising:

the contact state detection circuit comprises a current limiting resistor R, a direct current power supply module and a contactor KM1, and is used for being out of contact with the arc generator when the first electrode and the second electrode are judged to be in a stable contact state,

the control unit is also used for executing a detection closed-loop control mode when the contact state detection circuit is contacted with the arc generator, wherein the detection closed-loop control mode is to calculate the voltage variation as a feedback quantity and adjust the relative movement speed of the two electrodes until the voltage between the two electrodes is kept unchanged.

6. An arc fault occurrence control method applied to the arc fault occurrence apparatus according to claim 1, characterized by comprising the steps of,

a voltage sensor and a current sensor detect a voltage and a current between the first electrode and the second electrode respectively,

the control unit receives signals of the voltage sensor and the current sensor, judges the contact state between the first electrode and the second electrode according to the detected signals of the voltage sensor, performs arc generation simulation when the first electrode and the second electrode are judged to be stably contacted, judges the arc burning time according to the detection signals of the voltage sensor and the current sensor, and adjusts the interpolar voltage allowable value of the arc generator according to the arc burning time.

7. The arc fault occurrence control method of claim 6, further comprising the step of,

the control unit calculates a cycle voltage effective value U from the voltage U detected by the voltage sensor, and calculates a value satisfying 80% _s U > 20V, and the ratio of contact voltage to line current is greater than contact resistance R _jc As the arc time, U _s Is the supply voltage.

8. The arc fault occurrence control method according to claim 6, wherein an arc generation simulation phase is entered when the contact state of the first electrode and the second electrode is a stable contact, and further comprising a closed loop control step of PID including a voltage adjusting loop, a displacement loop, and a speed loop, wherein the voltage adjusting loop is an outer loop and takes the sustained arcing time deviation as an input, and the voltage regulator outputs a given voltage value; the middle ring is a displacement ring, the voltage deviation is used as an input quantity, and the displacement regulator outputs displacement variation quantity; the inner ring is a speed ring, takes the displacement deviation as input and is used for adjusting the running speed of the stepping motor.

9. The arc fault occurrence control method of claim 8, wherein the apparatus further comprises: the arc fault protector testing circuit is connected with the testing circuit state detection module and the testing circuit control module;

the contact state detection circuit comprises a current limiting resistor R, a direct-current power supply module and a contactor KM1, and the contact state circuit control and monitoring module is used for controlling and detecting the working state of the contactor KM 1;

the control method further comprises the step of executing a detection closed-loop control mode when the contact state detection circuit is in contact with the arc generator, wherein the detection closed-loop control mode is to calculate the voltage variation as a feedback quantity and adjust the relative movement speed of the two electrodes until the voltage between the two electrodes is kept unchanged.

10. The arc fault occurrence control method according to claim 9, wherein the control unit controls the contact state detection circuit to be out of contact with the arc generator when it is determined that the first electrode and the second electrode are stably in contact.

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