Residual current protection circuit breaker system for training

Abstract

The invention discloses a residual current protection circuit breaker system for training, which is characterized in that a parameter and threshold value reading unit reads a protection parameter threshold value preset by a residual current protection circuit breaker unit, a threshold value conversion unit converts various received protection parameter threshold values, converts required corresponding strong current signal numerical values, and sends the converted strong current signal numerical values to a controller; and the small signal generator sends out a corresponding weak current signal according to the received required weak current signal value and transmits the weak current signal to the residual current protection circuit breaker unit. On one hand, dynamic reading and issuing of circuit breaker protection parameters are achieved, the flexibility and adaptability of the system are improved, real-time updating and adjusting of various protection parameters are supported, the requirements of different scenes are met, on the other hand, high-precision conversion between strong electric signals and small-voltage / small-current signals is achieved, and high-precision conversion between the strong electric signals and the small-voltage / small-current signals is achieved. The accuracy and stability of signal output are ensured, the output signal is dynamically adjusted in combination with the preset threshold of the RCD, and the intelligent level of the system is improved.

Description

Technical Field

[0001] The present invention relates to the field of electric power training and assessment, and particularly to a residual current protection circuit breaker system for training. Background Art

[0002] With the continuous advancement of the construction of intelligent distribution networks, residual current protectors (RCDs) have become widely used in rural distribution substations and communities. There are a large number of devices with diverse models. Coupled with the complex distribution network, faults are extremely likely to occur. However, the skills of the personnel responsible for the operation and maintenance of such equipment are currently low, seriously affecting and restricting the safe operation level of the devices. In particular, many operation and maintenance personnel do not master the working principles and operation methods of residual current protectors (RCDs), do not understand the parameter settings and fault causes of the devices. When abnormal operating conditions occur in the devices, the operation and maintenance personnel cannot correctly handle and eliminate the faults, seriously affecting the safe operation of the equipment and the quality of power supply services. In order to standardize the operation process and ensure that the staff can proficiently master the operation skills, relevant personnel must be systematically trained and their skill levels must be strictly assessed. Only those who pass the assessment can obtain the qualification to take up their posts.

[0003] In the actual training scenario, in order to test or learn the protection functions of residual current protectors such as overload, short circuit, overvoltage, undervoltage, phase loss, and leakage, an adjustable power supply is required to provide real electrical parameters. For example, when testing overvoltage protection: when the overvoltage threshold is set to 265V, an AC voltage greater than 265V needs to be applied; when testing overload and short circuit protection, an AC current greater than the threshold also needs to be applied.

[0004] However, in such a case, this training scenario has the following disadvantages:

[0005] 1) The adjustable power supply is large in volume and high in cost: To test or learn residual current protectors, an adjustable power supply is needed to provide a voltage value greater than the threshold value for the residual current protector. At the same time, precise adjustable small current (mA) and large current (kA) greater than the threshold value are required. However, the power supplies that meet such requirements are often large in size and expensive in price.

[0006] 2) Risk of equipment damage: If the output of the adjustable power supply is unstable or exceeds the expected range, it may damage the residual current protector.

[0007] 3) Safety hazards: During the test, if the residual current protector cannot quickly cut off the power supply, an electric arc may be generated, leading to the risk of fire or electric shock, seriously affecting the safety of teachers and students. Summary of the Invention

[0008] In view of the above problems, the object of the present invention is to provide a residual current protective circuit breaker system for training, which can demonstrate the operation of the residual current protector (RCD) under various distribution line fault environments without connecting the residual current protector (RCD) to the real distribution environment, enabling the circuit breaker to artificially and controllably display the operation of the residual current protector (RCD) under various fault conditions and realizing training and teaching closer to the actual site.

[0009] The specific technical solution for achieving the object of the present invention is as follows:

[0010] A residual current protective circuit breaker system for training includes a power management unit, a parameter and threshold reading unit, a threshold conversion unit, a small signal generator, and a residual current protective circuit breaker unit;

[0011] The parameter and threshold reading unit is connected to the residual current protective circuit breaker unit, reads the preset protection parameter thresholds of the residual current protective circuit breaker unit, and transmits them to the threshold conversion unit;

[0012] The threshold conversion unit is respectively connected to the parameter and threshold reading unit and the small signal generator, converts various received protection parameter thresholds, converts the required corresponding strong electrical signal values, and transmits the converted required weak electrical signal values to the small signal generator;

[0013] The small signal generator is connected to the residual current protective circuit breaker unit, emits corresponding weak electrical signals according to the received required weak electrical signal values, and transmits them to the residual current protective circuit breaker unit;

[0014] The power management unit supplies power to each unit in the system.

[0015] Further, the protection parameter thresholds read by the parameter and threshold reading unit include overvoltage threshold, undervoltage threshold, open-phase threshold, zero-phase loss threshold, overcurrent threshold, short-circuit threshold, and residual operating current setting value.

[0016] Further, the process of converting the strong electrical signal value and the weak electrical signal value by the threshold conversion unit is as follows:

[0017] Obtain the theoretical proportionality coefficient K1 for conversion according to the model or specification of the residual current protective circuit breaker unit;

[0018] Correct the obtained theoretical proportionality coefficient K;

[0019] Based on the corrected proportionality coefficient, perform an equivalent conversion between the strong electrical signal value and the weak electrical signal value.

[0020] Further, the correction of the obtained proportionality coefficient K is specifically as follows:

[0021] Input a certain current or voltage signal to the residual current protection circuit breaker unit, and determine the theoretical signal value U2 that the residual current protection circuit breaker unit should measure according to the theoretical proportional coefficient K1. Read the actual signal value U3 actually measured by the residual current protection circuit breaker unit, obtain the error value △% of the proportional coefficient, so as to determine the corrected proportional coefficient K:

[0022]

[0023] K = (1 - △%)K1.

[0024] Further, the small signal generator includes an MCU unit, an FPGA waveform generation unit, a D / A conversion unit, and an LPF filtering unit;

[0025] Among them, the MCU unit communicates with the threshold conversion unit, receives the voltage and current signals to be output, controls the FPGA waveform generation unit to generate corresponding waveform data according to the amplitude and phase information of the received voltage and current waveforms, then converts it into an analog signal through the D / A conversion unit, and filters out the burrs and high-frequency components through the LPF filtering unit, and finally outputs a smooth sine wave signal to be connected to the residual current protection circuit breaker unit.

[0026] Further, the FPGA waveform generation unit includes a phase accumulator and a waveform data table module;

[0027] The input signals of the phase accumulator include the system clock, reset signal, frequency control word, and phase control word. Under the action of the system clock, the phase accumulator accumulates according to the frequency control word, generates a phase increment, and sets the initial phase according to the phase control word, and finally outputs the accumulated phase value, and its high P bits are used to address the waveform data table;

[0028] The input signals of the waveform data table module include the address, that is, the high P-bit output from the phase accumulator module and the system clock (CLOCK). The waveform data table module searches and outputs the corresponding waveform sampling value according to the input address, so as to output the digital quantity of the waveform sampling value.

[0029] Further, the cut-off frequency set by the LPF filtering unit is:

[0030]

[0031] Among them, R represents the resistance value of the filtering unit, and C represents the capacitance value of the filtering unit.

[0032] Further, the small signal generator and the residual current protection circuit breaker unit are connected through an operational amplifier circuit.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] (1) The residual current operated circuit breaker system for training of the present invention uses a small voltage and current signal generator to replace the strong electricity input, and uses weak electricity signals to replace strong electricity signals to implement the test of relevant functions. Only by adding a small signal generator to the sampling circuit of the residual current protector can the relevant protection measures be truly simulated, enabling trainees to understand its basic principle;

[0035] (2) The residual current operated circuit breaker system for training of the present invention is provided with a parameter and threshold reading unit and a threshold conversion unit. On the one hand, it realizes the dynamic reading and distribution of the breaker protection parameters, improves the flexibility and adaptability of the system, supports the real-time update and adjustment of various protection parameters, and meets the requirements of different scenarios. On the other hand, it realizes the high-precision conversion of strong electricity signals and small voltage / small current signals, ensures the accuracy and stability of signal output, combines with the preset threshold of the RCD, dynamically adjusts the output signal, and improves the intelligent level of the system;

[0036] (3) The solution of the present invention can be realized in the teaching process. Teachers can quickly change the sampled voltage and current values of the circuit breaker according to teaching needs without actually connecting to the 0.4kV distribution system through teaching software, and can be used to demonstrate the protection functions such as overload, short circuit, overvoltage, undervoltage, phase loss, and leakage of the residual current protector. In this way, not only can a real working environment be simulated, but also diverse teaching scenarios can be provided without incurring additional costs;

[0037] In the prior art, traditional circuit breakers need to be connected to a 0.4kV distribution environment, which has the potential risk of electric shock. This solution uses a safe voltage, completely avoiding the electric shock risk and ensuring the safety of training personnel;

[0038] This solution can also reduce the risk of equipment damage: Traditional circuit breakers are prone to damage during frequent operations in training. This solution uses simulation equipment, avoiding the loss of real equipment, extending the service life, enabling trainees to practice repeatedly, consolidating operation skills, and improving proficiency;

[0039] This solution can achieve real simulation: The simulated residual current protector can highly restore the working state under a 0.4kV distribution environment, providing a more real training experience, and can simulate various fault scenarios such as leakage and short circuit, helping trainees comprehensively master fault handling skills;

[0040] This solution can save training costs: The simulation equipment is easy to maintain, reducing maintenance expenses. There is no need for expensive 0.4kV distribution equipment, reducing training costs;

[0041] This solution can improve training efficiency: One-key reset or data distribution of the software is convenient and fast, improving training efficiency and shortening the training cycle;

[0042] This solution has portability: The simulated residual current protector is small in size and light in weight, making it convenient to carry and deploy;

[0043] This solution has flexibility: The training content and difficulty can be adjusted according to needs to adapt to different trainees;

[0044] This solution has environmental friendliness: It does not require real electricity, reducing energy consumption and carbon emissions.

[0045] The following further describes the present invention in conjunction with specific embodiments. Brief Description of the Drawings

[0046] Figure 1 It is a schematic diagram of the system architecture of the existing residual current protection circuit breaker for training.

[0047] Figure 2 It is a schematic diagram of the system architecture of the residual current protection circuit breaker for training of the present invention.

[0048] Figure 3 It is a schematic diagram of the threshold conversion unit of the residual current protection circuit breaker in the embodiment of the present invention.

[0049] Figure 4 It is a schematic diagram of the structure principle of the small signal generator in the embodiment of the present invention.

[0050] Figure 5 It is a schematic diagram of the internal signal generation process in the small signal generator in the embodiment of the present invention.

[0051] Figure 6 It is a flow chart of the breaker protection test in the embodiment of the present invention.

[0052] Figure 7 It is a control overall flow chart of the small signal generator in the embodiment of the present invention.

[0053] Figure 8 It is a DDS structure diagram implemented by the FPGA unit of the small signal generator in the embodiment of the present invention. Specific Embodiments

[0054] Embodiment

[0055] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts belong to the scope of protection of the present invention.

[0056] As shown in this application and the claims, unless the context clearly indicates otherwise, the words "a", "an", "one" and / or "the" are not specifically singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of the steps and elements that have been clearly identified, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0057] Unless otherwise specifically stated, the relative arrangements, numerical expressions and numerical values of the components and steps set forth in these embodiments do not limit the scope of this application. At the same time, it should be understood that for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn according to the actual proportional relationship. Technologies, methods and devices known to those of ordinary skill in the relevant field may not be discussed in detail, but where appropriate, the said technologies, methods and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0058] The schematic diagram of the existing residual current protection circuit breaker system for training is as Figure 1 shown, and it consists of a power management unit, a strong electricity interface, a three-way voltage sampling and operational amplifier circuit, a three-way current sampling and operational amplifier circuit, a zero-sequence current sampling and operational amplifier circuit, an MCU unit, a control and parameter setting unit, a closing and tripping control unit, a display unit, a communication unit, etc. It can perform closing and tripping operations for overload, short circuit, overvoltage, undervoltage, phase loss, leakage and other protections. The main implementation principle is to first set the corresponding overvoltage, undervoltage, overload, leakage and other threshold values, and then connect the residual current protection circuit breaker to the circuit. According to the three-phase voltages, three-phase currents and leakage current values measured by the three-way voltage sampling and operational amplifier circuit, the three-way current sampling and operational amplifier circuit, and the zero-sequence current sampling and operational amplifier circuit, and judge according to the preset protection parameter thresholds (such as overvoltage threshold, residual operating current setting value, action time comparison judgment, etc.). If it is detected that the threshold is exceeded, the module will act, and the control logic part will issue a tripping instruction to perform protection. The closing and tripping control unit is also responsible for reconnecting the circuit after the fault is eliminated (such as when the reclosing function is enabled and meets the reclosing conditions).

[0059] The display unit can display the current working state, voltage, current value, fault information, etc.

[0060] The communication part provides a communication interface with external devices (such as a host computer, a monitoring system, etc.) to achieve remote monitoring and fault diagnosis.

[0061] In order to test whether the corresponding overload, short - circuit, over - voltage, under - voltage, open - phase, leakage, etc. protections are normal, it is often necessary to apply strong electricity. For example, to test the over - voltage protection: when the over - voltage threshold is set to 265V, an AC voltage greater than 265V needs to be applied. Therefore, an adjustable voltage source is required. The over - current protection and leakage protection mechanisms are the same, and in both cases, a current value greater than the threshold value needs to be applied, so an adjustable current source is required. Large - current, voltage sources, and precise adjustable small - current sources (simulating adjustable leakage current) are large in volume, high in cost, and there are also safety hazards in operation as they need to be connected to strong electricity. The present invention replaces the strong - electricity interface part in Figure 1 with a small - voltage and current signal generator, and uses weak - electricity signals to replace strong - electricity signals to implement the test of relevant functions.

[0062] Combined with Figure 2 , a residual current protection circuit breaker system for training includes a power management unit, a parameter and threshold reading unit, a threshold conversion unit, a small - signal generator, and a residual current protection circuit breaker unit;

[0063] Among them, the residual current protection circuit breaker unit further includes a conventional MCU unit, a control and parameter setting unit, a closing and opening control unit, a display unit, a communication unit, etc.

[0064] The parameter and threshold reading unit is connected to the residual current protection circuit breaker unit, reads the preset protection parameter thresholds of the residual current protection circuit breaker unit, and transmits them to the threshold conversion unit;

[0065] The threshold conversion unit is respectively connected to the parameter and threshold reading unit and the small - signal generator, converts various received protection parameter thresholds, converts the required corresponding strong - electricity signal values, and transmits the converted required weak - electricity signal values to the small - signal generator;

[0066] The small - signal generator is connected to the residual current protection circuit breaker unit, emits corresponding weak - electricity signals according to the received required weak - electricity signal values, and transmits them to the residual current protection circuit breaker unit;

[0067] The power management unit supplies power to each unit in the system.

[0068] Among them, the main function of the parameter and threshold reading unit is to communicate with the MCU unit, read the preset protection parameter thresholds of the circuit breaker. The read protection parameter thresholds include over - voltage threshold, under - voltage threshold, open - phase threshold, zero - missing threshold, over - current threshold, short - circuit threshold, residual operating current setting value, and send these parameters to the threshold conversion unit and the small - signal generator through down - link communication.

[0069] The main function of the threshold conversion unit is to perform equivalent conversion on the strong electrical signal and the required small voltage and small current signals, and in combination with the protection parameter threshold limits preset by the circuit breaker read, send them to the small signal generator to control the small signal generator to output the required small voltage and small current threshold signals. The key points in the process of converting the strong electrical signal value and the weak electrical signal value by the threshold conversion unit are the equivalent relationship between the strong electrical signal and the weak electrical signal, and how to accurately convert the strong electrical voltage and current values into weak electrical voltage and current values;

[0070] The specific process includes: obtaining the theoretical proportional coefficient K1 for conversion according to the model or specification of the residual current protection circuit breaker unit. The sampling principles of each domestic manufacturer are basically the same. For voltage, a voltage dividing network and an operational amplifier are used, for current, a current transformer and an operational amplifier are used, and for leakage current measurement, a zero-sequence current transformer and an operational amplifier are used. The proportional coefficient K1 can be obtained by calculating the ratio of the strong electrical and weak electrical signals through principle calculation;

[0071] Taking the Beichen BCM9LE-400H residual current protection circuit breaker as an example: The three-way voltage sampling circuit is a voltage dividing network, and the schematic diagram is as Figure 3 shown;

[0072] U (weak electricity) = U strong electricity * (R3 + R4 + R5 + R6 + R7 + R8) / R8 = 0.00078U strong electricity; The corresponding voltage conversion proportional coefficient K1 = 0.00078;

[0073] After that, due to the differences in components such as the voltage dividing network and resistors, it is often necessary to correct them, and the obtained theoretical proportional coefficient K needs to be corrected;

[0074] Based on the corrected proportional coefficient, perform equivalent switching between the strong electrical signal value and the weak electrical signal value.

[0075] The correction of the obtained proportional coefficient K is specifically as follows:

[0076] Input a certain current or voltage signal to the residual current protection circuit breaker unit, and according to the theoretical proportional coefficient K1, determine the theoretical signal value U2 that the residual current protection circuit breaker unit should measure. Read the actual signal value U3 actually measured by the residual current protection circuit breaker unit, obtain the error value △% of the proportional coefficient, and thus determine the corrected proportional coefficient K:

[0077]

[0078] K = (1 - △%)K1.

[0079] In this embodiment, in order to accurately obtain the proportionality coefficient, the small signal generator is controlled to output a standard small voltage U1. Therefore, the corresponding theoretical high-voltage U2 = U1 / 0.00078. At this time, the actual voltage value U3 measured by the circuit breaker is read, and the error △% between the theoretical voltage U2 and the measured voltage U3 = (U3 - U2) / U2 * 100;

[0080] Then the actual coefficient K = (1 - △%)K1. Therefore, when simulating the output of a 265V voltage to test the overvoltage fault, it is only necessary to control the small signal generator to simulate the output of a small voltage value of 265*K.

[0081] The method of the current conversion coefficient K2 and the leakage current conversion coefficient K3 is the same as that of the voltage conversion coefficient;

[0082] Assuming that it is necessary to simulate an output of 400A, the small signal generator is controlled to output a small current signal of 400AK2;

[0083] When it is necessary to simulate a leakage current of 300mA, the small signal generator is controlled to output a small current signal of 300mAK2.

[0084] Thus, the equivalent switching between the weak electrical signal and the strong electrical signal is realized.

[0085] The main function of the small signal generator is to output three-channel voltages, three-channel currents, and zero-sequence current signals with adjustable amplitudes and phases according to the set values. The small signal generator adopts direct digital synthesis (Direct Digital Synthesis), uses the sampled values of the signal waveforms stored in the ROM, and then generates analog signals through digital-to-analog conversion. By changing the look-up table speed, the frequency can be changed, and the frequency can be continuously converted in real time with high frequency resolution. The basic structural schematic diagram is as Figure 4 and Figure 5 shown;

[0086] In this embodiment, the small signal generator includes an MCU unit, an FPGA waveform generation unit, a D / A conversion unit, and an LPF filtering unit;

[0087] Among them, the main function of the MCU unit is to communicate with the threshold conversion unit, receive the voltage and current signals to be output, control the FPGA waveform generation unit to generate corresponding waveform data according to the amplitude and phase information of the received voltage and current waveforms, then convert them into analog signals through the D / A conversion unit, and filter out the burrs and high-frequency components through the LPF filtering unit, and finally output a smooth sine wave signal to be connected to the residual current protection circuit breaker unit.

[0088] The FPGA waveform generation unit includes a phase accumulator and a waveform data table module;

[0089] The input signals of the phase accumulator include a system clock (CLOCK), a reset signal (RST_N), a frequency control word (FWORD) and a phase control word (PWORD). Under the action of the system clock, the phase accumulator accumulates according to the frequency control word, generates a phase increment, sets the initial phase according to the phase control word, and finally outputs the accumulated phase value, the high P bit of which is used to address the waveform data table;

[0090] The input signal of the waveform data table module includes the address, that is, the high P-bit output from the phase accumulator module and the system clock (CLOCK). The waveform data table module searches and outputs the corresponding waveform sampling value according to the input address, thereby outputting the digital quantity of the waveform sampling value.

[0091] D / A converter module: converts the digital value of waveform sampling value into analog value and outputs the required waveform.

[0092] The cut-off frequency set by the LPF filter unit is:

[0093]

[0094] Wherein, R represents the resistance value of the filter unit, and C represents the capacitance value of the filter unit.

[0095] In addition, the small signal generator and the residual current protection circuit breaker unit are connected via an operational amplifier circuit.

[0096] The system operation process of this embodiment includes:

[0097] The parameter and threshold reading unit reads the threshold value, using the 645 communication protocol that comes with the conventional circuit breaker. The threshold reading unit sends a line of code and automatically returns a set of threshold data. After reading and analyzing, it is sent through the 645 communication protocol and stored in the threshold conversion unit;

[0098] The threshold conversion unit calculates the weak current signal corresponding to the strong current threshold through conversion based on the received threshold data, and obtains the corresponding relationship;

[0099] The small signal generator simulates receiving and sending a small waveform of the data for detection by the circuit breaker original voltage sampling module;

[0100] For example, to achieve overvoltage tripping, it is necessary to simulate a voltage signal greater than the overvoltage threshold at the circuit breaker voltage weak current sampling port.

[0101] Input a strong voltage value greater than the strong voltage threshold, calculate a weak current signal data according to the proportional relationship calculated by the threshold conversion unit, and send it to the small signal generator. The small signal generator receives and simulates the small waveform of the data for detection by the original voltage sampling module of the circuit breaker, automatically determines the over-limit, and then realizes the circuit breaker protection action;

[0102] The circuit breaker protection test flow chart and the overall control flow chart of the small signal generator in this solution are as Figure 6 and 7 shown.

[0103] The following is attached with the partial code data structure definition diagram in the embodiments of this solution:

[0104] / / Define the data structure of the set parameters

[0105] typedef struct SetValueTypeDefStruct{

[0106] uint16_t AU_Value; / / Three-phase voltage amplitude, amplitude data format, two bytes, two decimal places, 0 - 12000

[0107] uint16_t AI_Value; / / Three-phase current amplitude

[0108] uint16_t UA_Value; / / UA voltage amplitude

[0109] uint16_t UB_Value;

[0110] uint16_t UC_Value;

[0111] uint16_t IA_Value; / / IA current amplitude

[0112] uint16_t IB_Value;

[0113] uint16_t IC_Value;

[0114] / * Define the data of the calibration register * /

[0115] struct MeasureModifyValueStructTypeDef{

[0116] uint16_t UGA_ValueModify;

[0117] uint16_t UGB_ValueModify;

[0118] uint16_t UGC_ValueModify;

[0119] uint16_t IGA_ValueModify;

[0120] uint16_t IGB_ValueModify;

[0121] uint16_t IGC_ValueModify;

[0122] f32 UIA_PhaseModify;

[0123] f32 UIB_PhaseModify;

[0124] f32 UIC_PhaseModify;

[0125] f32 UAB_PhaseModify;

[0126] f32 UAC_PhaseModify;

[0127] The residual current operated circuit breaker system for training of the present invention is provided with a parameter and threshold reading unit and a threshold conversion unit. On the one hand, it realizes the dynamic reading and distribution of the breaker protection parameters, improves the flexibility and adaptability of the system, supports the real-time update and adjustment of various protection parameters, and meets the requirements of different scenarios. On the other hand, it realizes the high-precision conversion of strong electrical signals and small voltage / small current signals, ensures the accuracy and stability of the signal output, combines with the preset threshold of the RCD, dynamically adjusts the output signal, improves the intelligent level of the system, and uses a small voltage and current signal generator to replace the strong electrical input, and uses weak electrical signals to replace strong electrical signals to test related functions. Only by adding a small signal generator to the sampling circuit of the residual current protector can the relevant protection measures be truly simulated, enabling trainees to understand its basic principle.

[0128] The above embodiments only represent several implementation manners of the present application, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several deformations and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the appended claims.

Claims

1. A residual current operated circuit breaker system for training, characterized in that, It includes a power management unit, a parameter and threshold reading unit, a threshold conversion unit, a small signal generator, and a residual current protection circuit breaker unit; The parameter and threshold reading unit is connected to the residual current protection circuit breaker unit, reads the preset protection parameter thresholds of the residual current protection circuit breaker unit, and transmits them to the threshold conversion unit; The threshold conversion unit is respectively connected to the parameter and threshold reading unit and the small signal generator, converts various received protection parameter thresholds, converts the required corresponding strong electrical signal values, and transmits the converted required weak electrical signal values to the small signal generator; The small signal generator is connected to the residual current protection circuit breaker unit, emits corresponding weak electrical signals according to the received required weak electrical signal values, and transmits them to the residual current protection circuit breaker unit; The power management unit supplies power to each unit in the system.

2. The residual current operated circuit breaker system for training according to claim 1, wherein The protection parameter thresholds read by the parameter and threshold reading unit include overvoltage threshold, undervoltage threshold, open-phase threshold, zero-phase loss threshold, overcurrent threshold, short-circuit threshold, and residual operating current setting value.

3. The residual current operated circuit breaker system for training according to claim 1, wherein The process of the threshold conversion unit converting strong electrical signal values and weak electrical signal values is as follows: Obtain the theoretical proportionality coefficient K1 for conversion according to the model or specification of the residual current protection circuit breaker unit; Correct the obtained theoretical proportionality coefficient K; Based on the corrected proportionality coefficient, perform equivalent switching between strong electrical signal values and weak electrical signal values.

4. The residual current operated circuit breaker system for training according to claim 3, characterized in that, The correction of the obtained proportionality coefficient K is specifically as follows: Input a certain current or voltage signal to the residual current protection circuit breaker unit, determine the theoretical signal value U2 that the residual current protection circuit breaker unit should measure according to the theoretical proportionality coefficient K1, read the actual signal value U3 actually measured by the residual current protection circuit breaker unit, obtain the error value △% of the proportionality coefficient, and thus determine the corrected proportionality coefficient K: K = (1 - △%)K1.

5. The residual current operated circuit breaker system for training according to claim 1, characterized in that The small signal generator includes an MCU unit, an FPGA waveform generation unit, a D / A conversion unit, and an LPF filtering unit; Among them, the MCU unit communicates with the threshold conversion unit, receives the voltage and current signals to be output, controls the FPGA waveform generation unit to generate corresponding waveform data according to the amplitude and phase information of the received voltage and current waveforms, then converts them into analog signals through the D / A conversion unit, and filters out the burrs and high-frequency components through the LPF filtering unit, and finally outputs a smooth sine wave signal to be connected to the residual current protection circuit breaker unit.

6. The residual current operated circuit breaker system for training according to claim 5, characterized in that, The FPGA waveform generation unit includes a phase accumulator and a waveform data table module; The input signals of the phase accumulator include a system clock, a reset signal, a frequency control word, and a phase control word. Under the action of the system clock, the phase accumulator accumulates according to the frequency control word, generates a phase increment, sets the initial phase according to the phase control word, and finally outputs the accumulated phase value, and its high P bits are used to address the waveform data table; The input signals of the waveform data table module include an address, namely the high P-bit output from the phase accumulator module and the system clock (CLOCK). The waveform data table module looks up and outputs the corresponding waveform sampling value according to the input address, thereby outputting the digital quantity of the waveform sampling value.

7. The residual current operated circuit breaker system for training according to claim 5, characterized in that, The cut-off frequency set by the LPF filtering unit is: where R represents the resistance value of the filtering unit and C represents the capacitance value of the filtering unit.

8. The residual current protection circuit breaker system for training according to claim 1, characterized in that, The small signal generator and the residual current protection circuit breaker unit are connected through an operational amplifier circuit.

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