Molded case circuit breaker intelligent module integrating multiple functions

Abstract

The invention relates to a molded case circuit breaker intelligent module integrating multiple functions. The molded case circuit breaker intelligent module integrates the functions of data acquisition, remote communication, man-machine interaction, metering protection, topology identification, event recording, temperature measurement and the like. Key parameters, including voltage, current, power, power factor, power grid frequency, electric energy and the like, in a power system can be collected in real time through data collection, meanwhile, voltage and current unbalance detection and harmonic detection are achieved, and metering current and protection current can be calculated and displayed respectively. The communication module comprises serial port communication, Bluetooth communication and carrier communication, and supports multiple communication protocols. A liquid crystal display screen and keys are arranged in the aspect of man-machine interaction, a visual user interface is provided, and field operation and parameter setting are facilitated. The protection function provides a plurality of protection mechanisms, such as overload, short circuit, overvoltage, undervoltage, phase loss, zero line breaking and temperature protection, so as to prevent and reduce faults of a power system. The topology identification module can autonomously modulate and send the characteristic current and analyze the characteristic current, so that the area topology can be conveniently identified. Meanwhile, an event recording function is achieved, and opening and closing events, remote signaling displacement events and protection comprehensive events can be recorded respectively. The temperature measurement function can collect the real-time temperature of six paths of three-phase incoming lines and outgoing lines in real time, and normal operation of the temperature protection function is ensured. The modular design is adopted, shell frame circuit breakers of different current specifications are supported, plug and play is achieved, and the operation and maintenance cost is reduced.

Description

Technical Field

[0001] The invention belongs to the field of electrical equipment, and in particular relates to a molded case circuit breaker intelligent module integrating multiple functions. Background Art

[0002] The statements in this section merely mention background technology related to the present application and do not necessarily constitute prior art.

[0003] When a fault occurs in a traditional distribution network, it often relies on manual inspections and user reports, which results in slow fault response and processing, affecting power supply reliability. By deploying intelligent modules, real-time monitoring and automatic fault detection can be achieved. Once an abnormality is detected, the fault can be quickly located and the protection mechanism can be activated, reducing power outage time and improving the self-healing ability of the power grid.

[0004] The fluctuation and abnormality of electric energy pose a threat to the stable operation of the power system and the safe use of users' electrical equipment, and it is difficult to achieve comprehensive monitoring and effective control of power quality with traditional methods. The intelligent module integrates high-precision power quality monitoring function, which can monitor the fluctuation of parameters such as voltage, current, and frequency in real time, and analyze and adjust them through intelligent algorithms to ensure that the power quality meets the standards and reduce the impact of power quality problems on users.

[0005] Therefore, how to design a molded case circuit breaker intelligent module integrating multiple functions is a technical problem to be solved by the present invention. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention provides a molded case circuit breaker intelligent module integrating multiple functions, realizing non-stop replacement and remote maintenance, and meeting the development needs of the smart grid.

[0007] The technical solution adopted by the present invention to solve the technical problem is as follows:

[0008] An intelligent module for molded case circuit breakers integrating multiple functions, characterized in that the module integrates functions such as data acquisition, remote communication, human-computer interaction, metering protection, topology identification, and event recording;

[0009] As a preferred technical solution, the module has a universal design, supports current specifications of 125A, 250A, 400A, and 630A, realizes the intelligence of the frame circuit breaker, improves the reliability of the equipment and reduces the operation and maintenance cost, does not distinguish the current specifications and bases of the low-voltage intelligent switch, ensures that the shells of different current levels can be interchanged without additional adaptation, has adaptive and self-calibration functions, and supports plug-and-play;

[0010] As a preferred technical solution, the hot-swap function does not affect the primary operation, avoiding the need for the entire circuit breaker to be replaced due to damage to the secondary part of the traditional primary and secondary integrated intelligent circuit breaker, thus solving the problem of different lifespans of the primary and secondary equipment.

[0011] As a preferred technical solution, the remote communication function also includes a remote upgrade function, which supports communication between the host computer and the module for firmware update. The remote upgrade function adopts the DLT645 communication protocol;

[0012] As a preferred technical solution, the remote upgrade function has its own verification for each package of upgrade data. When the program upgrade is suspended due to an accident, the original program will not be overwritten, thus ensuring the normal operation of the module.

[0013] As a preferred technical solution, the intelligent module of a molded case circuit breaker with integrated multiple functions is characterized in that the current protection of the metering protection function adopts three-stage protection, the long delay of overload is inverse time protection, the short delay of short circuit is definite time protection, and the short circuit instantaneous is unlimited time protection. The metering protection function, the metering calibration is divided into two parts: calibration and ratio difference calibration, the calibration formula is: calibration value = original value / actual value, the ratio difference calculation formula is: The protection current calculation function is divided into a linear interval (less than 3 times the rated current) and a saturation interval (greater than 3 times the rated current). The saturation interval current calculation uses 0.7 times the peak-to-peak value of the current and 0.3 times the root mean square value of the current;

[0014] As a preferred technical solution, the protection current calculation function provides current compensation coefficients for three-phase protection current calculations of 2 to 3 times, 3 to 5 times, and 5 times or more of the rated current, respectively, to ensure that the current error in each interval is less than 10% (less than 2% in the linear interval). This current compensation coefficient can be set by pressing a button or a host computer and stored in real time.

[0015] As a preferred technical solution, the event recording function can record information including the current year, month, day, hour, minute, and second, the number of event transmissions, the current opening and closing reasons, whether it is an electronic trip, and the three-phase instantaneous current / voltage;

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention has three communication modes: Bluetooth communication, serial communication and carrier communication. The latter two also support Modbus-RTU and DLT645 dual protocols. They can realize intelligent interconnection between devices and remote data collection for different application scenarios, perform fault diagnosis, status monitoring and parameter configuration in time, reduce the frequency of on-site inspections, and improve response speed.

[0018] The present invention has the function of substation topology identification based on characteristic current. It can not only generate a modulation signal with a specific rule through pulse width modulation technology to realize the output of characteristic current, but also perform signal current sampling, calculate and extract characteristic codes at specific frequency points, and then determine the electrical topology relationship between the sending device and the identification device, thereby reducing the risks brought by manpower, material resources investment and pole climbing and other work.

[0019] The present invention has an event recording function, which can complete the recording of instantaneous tripping events within 70ms at the fastest. It can record the opening and closing events, remote signal change events and protection comprehensive events respectively. Each type of event can record up to the most recent 100 events, and the record content includes the current year, month, day, hour, minute and second, the number of event sending, the current opening and closing reasons, whether it is electronic tripping, and the three-phase instantaneous current / voltage.

[0020] The present invention has a measurement and correction function, and can perform high-precision one-key calibration on three-phase current, voltage, grid frequency, active power, reactive power, apparent power, and power factor, with a maximum error of no more than 0.5%. The plastic shell base for different types of mutual inductors can also be switched with one key through the human-computer interaction interface.

[0021] The present invention has a modular universal design, supports current specifications from 125A, 250A, 400A, and 630A, realizes the intelligence of the frame circuit breaker to improve the reliability of the equipment and reduce the operation and maintenance cost. It does not distinguish between the current specifications and bases of the low-voltage intelligent switch, ensures that the shells of different current levels can be interchangeable without additional adaptation, has adaptive and self-calibration functions, and supports plug-and-play. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a functional module decomposition block diagram of an embodiment of the present invention.

[0023] Figure 2 It is a schematic diagram of the overall structure of an embodiment of the present invention. DETAILED DESCRIPTION

[0024] To further illustrate the embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, a person of ordinary skill in the art should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0025] The present invention will now be further described in conjunction with the accompanying drawings and specific implementations. A specific embodiment of the present invention will be described with reference to the following figures.

[0026] In the present application embodiment, Figure 1The molded case circuit breaker intelligent module shown integrates multiple functions, which includes an external signal input, a CT adapter board, a molded case circuit breaker intelligent module, a temperature sensor board and a carrier module baseboard.

[0027] The A-phase metering current sampling signal is input to the signal transfer terminal 30a and the signal transfer terminal 30b through the signal input terminal 10a, the B-phase metering current sampling signal is input to the signal input terminal 10b, the C-phase metering current sampling signal is input to the signal input terminal 10c, the A-phase protection current sampling signal is input to the signal input terminal 10a, the B-phase protection current sampling signal is input to the signal input terminal 10b, and the C-phase protection current sampling signal is input to the signal transfer terminal 30a and the signal transfer terminal 30b through the signal input terminal 10c;

[0028] Further, the signal is input to the signal transfer mother row 70a and the signal transfer mother row 70b through the signal transfer terminal 30a and the signal transfer terminal 30b, and finally output to the signal transfer pin row 50a, and connected to the three-phase metering chip 60b and the main control microcontroller 60a;

[0029] The metering current sampling signals of phase A, phase B and phase C are input through the three-phase metering transformer 12 connected to the power grid, converted into current signals through the metering current signal rectifier 21 and connected to the three-phase metering chip 54; the protection current sampling signals of phase A, phase B and phase C are input through the three-phase protection transformer 13 connected to the power grid, converted into current signals through the protection current signal rectifier 22 and connected to the three-phase metering chip 54, and then transferred to the main control microcontroller 53; the voltage sampling signals of phase A, phase B, phase C and phase N are respectively converted into three-phase voltage metering signals through the two-wire one-phase rectifier 52 and connected to the three-phase metering chip 53.

[0030] The data acquisition function is to calculate the real-time voltage, current, power, power factor, grid frequency and electric energy by the current signal and voltage signal connected to the three-phase metering chip 53, and further obtain the original waveform data of the current and voltage. The main control microcontroller 53 can calculate the 2nd to 32nd harmonics of the three-phase current and voltage by analyzing the original waveform. The current and voltage deviations can be calculated by comparing the actual voltage and current with the rated voltage and current, and the voltage imbalance can be calculated by the amplitude method.

[0031] In order to improve the accuracy of the metering data, it is necessary to calibrate the collected voltage, current, power, power factor, etc., which is divided into two parts: calibration and ratio calibration. First, calibration is performed. In order to facilitate calculation, high-precision equipment can be used as the input source for external signal input. The current and voltage values ​​to be input are set, generally the rated current and rated voltage, and the original values ​​of the corresponding registers of the corresponding current, voltage, power, power factor, and grid frequency are obtained through the three-phase metering chip 54. The calibration value is calculated and input to the main control microcontroller 53, and the calibration value = the read original value / actual value.

[0032] Furthermore, if the accuracy of the metering data obtained at this time still does not meet the requirements, a ratio difference calibration is required. Adjust the input source to half of the rated voltage and rated current, and adjust the power factor to 1 and 0.5 respectively. The ratio difference calculation formulas for voltage, current, power, and power factor are: The calculated ratio difference is input into the corresponding register of the three-phase metering chip 54 to obtain more accurate metering data.

[0033] In the embodiment of the present application, the metering protection function provides a variety of protection mechanisms, such as overload, short circuit, overvoltage, undervoltage, phase loss, zero break and temperature protection, to prevent and reduce power system failures. The above protection mechanisms are all within the rated current and rated voltage range. However, for instantaneous large current overloads, an additional three-stage current protection scheme is also provided. The sampling signal of this scheme is distinguished from the metering signal input, that is, the metering current and the protection current can be calculated and displayed separately, and the protection current is specifically applied to the three-stage current protection scheme.

[0034] The current protection is a three-stage protection, namely overload long delay, short circuit short delay and short circuit instantaneous. Among them, overload long delay is inverse time protection, short circuit short delay is definite time protection, and short circuit instantaneous is unlimited time protection. The overload long delay setting current range is 0.4 to 1 times the rated current, the starting current range is 1.08 to 1.18 times the rated current, and the delay setting range is 6 to 300 seconds; the short circuit short delay setting current range is 2 to 12 times the rated current, and the delay setting range is 60 to 400 milliseconds; the short circuit instantaneous setting current range is 3 to 14 times the rated current, with no delay.

[0035] Assuming that the overload long delay starting current is less than the actual current and less than the short circuit short delay setting current, the protection action time = (2*Ir1÷actual current)2*t1; further, assuming that the short circuit short delay setting current is less than the actual current and less than the short circuit instantaneous setting current, the protection action time needs to be compared with the short circuit short delay time and the overload long delay protection time. The shorter time will be used as the protection action time; overload long delay protection time = (2*Ir1÷actual current)2*t1; if the current exceeds the short circuit instantaneous setting current, the circuit breaker will trip immediately.

[0036] For example: now the overload long delay is 12 seconds, the overload long delay setting current is 250A, the overload long delay starting current is 300A, the short circuit short delay setting current is 400A; the short circuit short delay time is 1s; the short circuit instantaneous setting current is 2000A, and the actual current flows through 500A. According to the above data, the overload long delay protection time can be calculated = (2*250 / 500)2*12=12s; since the short circuit short delay time is only 1s < the overload long delay protection time 12s, the actual protection action time is equal to 1s;

[0037] The above is a description of the three-stage current protection characteristics. In order to trigger the current protection function of each interval normally, the accuracy of the protection current calculation is required to be high. In this regard, the protection current calculation function and the protection current calibration are divided into a linear interval (below 3 times the rated current) and a saturation interval (greater than 3 times the rated current). By sampling and observing a large amount of data of transformers of different specifications and models, it is found that when the current is below 3 times the rated current, the actual current value is linearly related to the sampled value; when the current is 3 to 14 times the rated current, the actual current value and the sampled value are saturated. At this time, the original value needs to be sampled at a certain current interval as the interval, and the current protection characteristic curve is obtained by fitting with the actual value. Below 3 times the rated current, the current root mean square fitting is adopted; above 3 times the rated current, a certain ratio of current root mean square and peak-to-peak value fitting curve is adopted. In addition, on the basis of the protection current calculation of 2 to 3 times, 3 to 5 times, and 5 times or more, a new current coefficient is added to fine-tune the current slope mutation point of each interval. The current compensation coefficient can be set by buttons 80a, 80b, 80c and 80d or the host computer;

[0038] Furthermore, the protection current curve, protection current coefficient, and calibration information can all be stored in the storage chip 40a on the CT adapter board. This solution adopts a universal design, so after the smart module is damaged, a new module can be immediately replaced and the original protection current curve, protection current coefficient, and calibration information can be read, avoiding duplication of work and achieving plug-and-play.

[0039] In the embodiment of the present application, the event recording function can record the opening and closing events, the remote signal change events and the comprehensive protection events respectively. Each type of event can record up to 100 recent events, and the record content includes the current year, month, day, hour, minute and second, the number of event transmissions, the current opening and closing reasons, whether it is electronic tripping, and the three-phase instantaneous current / voltage. The event record judgment logic is as follows: starting from obtaining the current protection alarm status, determine whether there is a current tripping reason. If there is no tripping reason (N), the process ends and no event recording is performed; if there is a tripping reason (Y), check whether the number of comprehensive event records, opening and closing records and remote signal change records exceeds 100. If the number of records exceeds 100, overwrite the previous one with the latest event record; if it does not exceed 100, obtain the current year, month, day, hour, minute and second; obtain the current tripping reason and opening and closing status. If the current operation is not electric control, the last operation was instantaneous, and the current closing operation is performed, then this closing operation is instantaneous; obtain the saved value of the current A / B / C phase protection current; determine whether the current opening reason exists and whether it is instantaneous or short-delayed. If it is instantaneous or short-delayed (Y), save it to the comprehensive event record; determine whether the current opening reason is remote signaling. If it is remote signaling (Y), save it to the remote signaling change record. If it is not remote signaling (N), because the tripping reason is instantaneous or short-delayed, use quick recording.

[0040] Furthermore, the protection alarm status mentioned above includes normal operation, short circuit instantaneous, short circuit short delay, overload long delay, overvoltage, low voltage, phase loss, zero break, remote signal input, high temperature, remote control command, non-electric control and other above-mentioned states. The above-mentioned fast recording function is only enabled when there is an overload and large current passing through the power grid and it is judged to be a short circuit instantaneous or short circuit short delay state. If the protection alarm state is judged to be a short circuit instantaneous or a short circuit short delay, the module will first send a trip command to the circuit breaker to ensure that the protection circuit can be powered off immediately. At this time, the module is briefly powered by the large capacitor 90a, and the opening and closing events can be recorded and stored in the storage chip 40a;

[0041] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, it should be understood by those skilled in the art that various changes may be made to the present invention in form and details without departing from the spirit and scope of the present invention as defined by the appended claims, all of which are within the scope of protection of the present invention.

Claims

1. A molded case circuit breaker intelligent module integrating multiple functions, characterized in that The module integrates functions such as data acquisition, remote communication, human-computer interaction, metering protection, topology identification, and event recording. The data acquisition function can collect key parameters in the power system in real time, including voltage, current, power, power factor, grid frequency, and electric energy, and it also has voltage and current imbalance detection and harmonic detection. The metering current and protection current can be calculated and displayed separately. The remote communication function includes serial communication, Bluetooth communication, and carrier communication, and supports Modbus-RTU and DLT645 communication protocols. The human-computer interaction function is equipped with an LCD display and buttons, providing an intuitive user interface to facilitate on-site operation and parameter setting. The metering protection function provides a variety of protection mechanisms, such as overload, short circuit, overvoltage, undervoltage, phase loss, zero break, and temperature protection to prevent and reduce power system failures. The topology identification function can autonomously modulate and send characteristic currents and analyze characteristic currents to facilitate identification of substation topology. The event recording function can record opening and closing events, remote signal change events, and protection comprehensive events separately.

2. The intelligent module of a molded case circuit breaker integrating multiple functions according to claim 1, characterized in that: The module has a universal design and supports current specifications from 125A, 250A, 400A, and 630A, realizing the intelligence of the frame circuit breaker to improve the reliability of the equipment and reduce the operation and maintenance costs. It does not distinguish between the current specifications and bases of the low-voltage intelligent switch, ensuring that shells of different current levels can be interchanged without additional adaptation, has adaptive and self-calibration functions, and supports plug-and-play.

3. The intelligent module of a molded case circuit breaker integrating multiple functions according to claim 1, characterized in that: The hot-swap function does not affect the primary operation, thus avoiding the situation where the entire circuit breaker needs to be powered off for replacement due to damage to the secondary part of the traditional primary and secondary integrated intelligent circuit breaker, and solving the problem of different lifespans of the primary and secondary equipment.

4. The intelligent module for molded case circuit breaker integrating multiple functions according to claim 1, characterized in that: The remote communication function also includes a remote upgrade function, which supports communication between the host computer and the module for firmware update. The remote upgrade function adopts the DLT6451 communication protocol.

5. The intelligent module of a molded case circuit breaker integrating multiple functions according to claim 1, characterized in that: The remote upgrade function has its own verification for each package of upgrade data. When the program upgrade is suspended due to an accident, the original program will not be overwritten, thus ensuring the normal operation of the module.

6. The intelligent module of a molded case circuit breaker integrating multiple functions according to claim 1, characterized in that: The metering protection function adopts three-stage protection for current protection, with long delay for overload as inverse time protection, short delay for short circuit as definite time protection, and instantaneous short circuit as unlimited time protection. The metering protection function has two parts: calibration and ratio difference calibration. The calibration formula is: calibration value = original value / actual value, and the ratio difference calculation formula is: The protection current calculation function, the protection current calibration is divided into a linear interval (below 3 times the rated current) and a saturation interval (greater than 3 times the rated current), and the saturation interval current calculation uses 0.7 times the current peak-to-peak value and 0.3 times the current root mean square value.

7. The intelligent module of a molded case circuit breaker integrating multiple functions according to claim 1, characterized in that: The protection current calculation function provides current compensation coefficients for three-phase protection current calculations of 2 to 3 times, 3 to 5 times, and more than 5 times the rated current, respectively, to ensure that the current error in each interval is less than 10% (the linear interval is less than 2%). This current compensation coefficient can be adjusted by buttons or a host computer and stored in real time.

8. The intelligent module for molded case circuit breaker integrating multiple functions according to claim 1, characterized in that: The event recording function can record information including the current year, month, day, hour, minute, and second, the number of times the event is sent, the current opening and closing reason, whether it is an electronic trip, and the three-phase instantaneous current / voltage.

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