Improved residual current alarm method

Abstract

The application relates to the field of power switching, and aims to provide an improved residual current alarm method, a main power current transformer is used for obtaining a residual current value alpha on a three-phase line of a main power supply, a standby power current transformer is used for obtaining a residual current value beta on a three-phase line of a standby power supply, a signal processing device comprises a current analysis unit and a power control unit, the current analysis unit is used for calculating the current value on the main power supply and the standby power supply, the current value is compared with a pre-stored current threshold value, and then the power control unit is driven to close the power supply not meeting the standard, a large data function is calculated through self-development, an engineer is assisted to remotely understand power supply conditions, hidden dangers are completely eliminated, intelligent monitoring can be realized all day long for tourist attractions, small villages and building groups far away from the city, and the foresighted failure can be intervened in advance.

Description

Technical Field

[0001] This invention relates to the technical field of residual current monitoring, and specifically to an improved residual current alarm method. Background Technology

[0002] With the improvement of social standards, intelligent and modern large-scale enclosed venues have emerged, and power distribution cabinets are the fundamental guarantee for their stable operation. To further improve electrical safety and reduce the impact of electrical fires, my country has gradually increased its emphasis on fire safety, especially on preventing electrical fires. Relevant national departments have successively issued design standards such as "GB50054—2011 Low-voltage Power Distribution Design Code" and "GB50116—2013 Automatic Fire Alarm Design Code." Residual current fire detectors are gradually being used in various low-voltage power distribution systems. However, due to the high technical requirements of this equipment, false alarms and missed alarms often occur in actual construction due to problems such as mixed use of neutral and ground wires, damaged wire insulation, leakage of electrical equipment, and short circuits in double-circuit neutral wires. Among these, false alarms caused by short circuits in double-circuit neutral wires are particularly serious.

[0003] The prior art, with publication number CN202405861U and patent titled "A Backup Power Generation Device," discloses a backup power generation device with strong applicability to power systems and high operational reliability. Both the mains power supply and the backup power supply are connected to a control cabinet. The device includes a mains power circuit isolating switch, a miniature circuit breaker, and a dual power conversion device. The mains power supply is connected to the power terminal at the lower end of the control cabinet, which is connected to the mains power circuit isolating switch. The output of the isolating switch is connected to the input of the dual power conversion device. The input and output of the miniature circuit breaker are connected to the backup power supply and the dual power conversion device, respectively. The output of the dual power conversion device is connected to the load. The dual power conversion device includes a main board, an analog sampling board, a relay board, an intermediate relay, a controller, and a dual power conversion switch. The mains voltage signal sequentially passes through the analog sampling board, main board, relay board, intermediate relay, controller, and dual power conversion switch. The mains voltage signal is also input to the intermediate relay. The aforementioned electrical components enable the switching of backup power supplies. However, the drawbacks are also quite obvious: the large number of electrical components makes it impossible to directly identify the source of the fault and pinpoint the specific faulty appliance once a line fault is detected. Therefore, in modern intelligent industry, intelligent monitoring and switching of backup power supplies should be adopted. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art. It achieves the monitoring of residual current in the power supply box through more miniaturized integrated components, and assists engineers in remotely understanding the power supply status through self-developed big data function calculation, thereby completely eliminating safety hazards. For tourist attractions and small villages in remote urban areas, it can achieve all-day intelligent monitoring and intervene in advance for foreseeable faults.

[0005] Specifically, this is achieved through the following technical solution: an improved residual current alarm method, wherein a main power supply current transformer is used to obtain the residual current value on the three-phase main power supply line. The backup power current transformer is used to obtain the residual current value on the three-phase backup power line. , The signal processing device includes a current analysis unit and a power control unit. The current analysis unit calculates the current values ​​on the main power supply and the backup power supply, compares them with the pre-stored current threshold, and then drives the power control unit to shut down the power supply that does not meet the standard.

[0006] By using the above-mentioned technical means, the insulation level between the live wire and the neutral wire in the circuit can be determined by the value of the leakage current, thereby determining whether the circuit insulation is intact.

[0007] Preferably, the current analysis unit includes an amplification unit, a conversion unit, a processing unit, and a signal output unit. After receiving the residual current signal, the amplification unit amplifies and outputs the signal, which is then sent to the conversion unit. The conversion unit converts the analog signal into a digital signal and sends it to the processing unit. The processing unit stores a current threshold value, and after comparison and judgment, the output unit outputs a drive signal.

[0008] Using the aforementioned technical means, after collecting current data, the residual current type electrical fire detector will display the analyzed data in the background.

[0009] Preferably, the power control unit includes an input unit, a control unit, and a drive unit. The input unit is used to receive drive signals and send drive signals to the control unit. The control unit sends alarm signals and shutdown signals. After receiving the shutdown signal, the drive unit converts the digital signal into an analog signal and executes the circuit breaker to shut off the corresponding power supply.

[0010] Through the aforementioned technical means, the switching between main and backup power supplies can be effectively achieved by signal conversion, avoiding potential hazards such as short circuits and power outages caused by untimely power failure switching.

[0011] Preferably, the current analysis unit collects the residual current values ​​on the three-phase lines of the main and backup power supplies. and The specific data collection method includes the following steps: Step S1: The amplification unit compares the residual current collected within the acquisition period T. When the curves coincide, the data is sent to step S3; when the curves do not coincide, the data is sent to step S2. Step S2: Adjust the acquisition period T. By reducing the size of the period T, lock the boundary point of the curve and send the time of the boundary point to the alarm display unit in the current analysis unit. Step S3: Send the collected analog curves that overlap within multiple periods to the conversion unit.

[0012] By employing the aforementioned technical means, the residual current value of the dual-side power supply is obtained within a time period. Through analog quantity comparison, function calculation, and digital quantity transmission, the accurate dynamic residual current situation is obtained.

[0013] Preferably, in step S1, the residual current value at any given time... The calculation formula is as follows: ; ; ; .

[0014] In the formula, the residual current value on the main power supply at a certain moment is... Three phase currents , , and the main power supply neutral line The vector and absolute values ​​of the residual current at a certain moment on the backup power supply. Three phase currents , , and the main power supply neutral line The vector and absolute value, Defined as comparing whether the solutions of multiple functions are the same. This represents the number of solutions to the corresponding function. It is a natural integer. This represents the function with the maximum number of solutions occurring within period T, where n is a quantifier that needs to be manually set, and period T is the acquisition period of the amplification unit. The residual current value at time tn. and The sampling period T and sampling time t are the same, and the curve in step S1 passes through the above residual current value. and The result obtained from the calculation.

[0015] Through the aforementioned technical means, research has revealed that the residual current value exhibits irregular signal fluctuations over a period of time. These irregular changes are difficult to capture and their effectiveness cannot be defined. However, the safety hazards they pose cannot be ignored. Therefore, through extensive data research, the aforementioned mathematical formula was derived to calculate the effectiveness of the residual current value over a period of time. The most frequently occurring residual current value was extracted as the solution to the function, representing the residual current value for that period.

[0016] Preferably, there is at least one backup power source.

[0017] Through the above technical means, the above calculation formula is not limited to one backup power source, but can be multiple backup power sources, thereby enabling the main power source to compare the residual current values ​​of multiple backup power sources and select the most suitable power supply.

[0018] Preferably, the alarm display unit in the current analysis unit operates when the residual current value is not 0.

[0019] The aforementioned technical means are used to provide early warning of power supply stability issues through the alarm display unit in the field equipment.

[0020] Preferably, the alarm display unit sends the dynamic curve to the cloud via the communication unit.

[0021] The aforementioned technical means facilitate remote staff to understand the power supply status of specific lines.

[0022] The beneficial effects of this invention are: (1) Integrate the signals collected from the residual current in the main power supply and the backup power supply, and send the integrated signal to the field processing equipment. (2) It is used for precise current and voltage sampling and monitoring when dual or multiple power supplies are in operation, so as to realize the scientific switching of dual or multiple power supplies. Attached Figure Description

[0023] Figure 1 is an overall system block diagram of the present invention; Figure 2 is a schematic diagram of the residual current sampling principle of the present invention. Detailed Implementation

[0024] The following description, in conjunction with the appendix of the present invention, Figures 1-2 The technical solutions in the embodiments of the present invention are clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this application.

[0025] Please refer to Figure 1It includes a signal processing unit and multiple current transformers. The main power supply current transformer is used to obtain the residual current value on the three-phase main power supply line. The backup power current transformer is used to obtain the residual current value on the three-phase backup power line. , The signal processing device includes a current analysis unit and a power control unit. The current analysis unit calculates the current values ​​on the main power supply and the backup power supply, compares them with the pre-stored current threshold, and then drives the power control unit to shut down the power supply that does not meet the standard.

[0026] Those skilled in the art will know that the remaining current value can be calculated from the current values ​​on the three-phase lines of the power supply, and the fluctuation of the current value can directly indicate the operating status of the power supply. With the development of intelligent electrical appliances, a stable and continuous supply of electrical energy can stimulate higher industrial output and quality of life. In order to achieve zero power outages, dual or multiple power supplies are often configured in important locations to avoid problems such as easy failure and high maintenance costs that occur under a single power supply.

[0027] It is worth noting that the components appearing in this embodiment are common electrical components in the prior art, including but not limited to communication units, amplification units, conversion units, and control units. In this invention, the functions of each unit component are defined, and they can all be directly matched with common models of components in the prior art. This invention aims to improve computer programs and big data calculations by utilizing the combination of existing components, adapt to circuit systems with multiple power supplies integrated, and select the best power supply.

[0028] It is worth noting that the current analysis unit collects the residual current values ​​on the three-phase lines of the main and backup power supplies. and The specific data collection method includes the following steps: Step S1: The amplification unit compares the residual current collected within the acquisition period T. When the curves coincide, the data is sent to step S3; when the curves do not coincide, the data is sent to step S2. Step S2: Adjust the acquisition period T. By reducing the size of the period T, lock the boundary point of the curve and send the time of the boundary point to the alarm display unit in the current analysis unit. Step S3: Send the collected analog curves that overlap within multiple periods to the conversion unit.

[0029] It is worth noting that, please refer to Figure 2 By collecting and calculating data in real time, it can determine whether the residual current fluctuation value of a single power supply is reasonable. If it is unreasonable, it can lock the time when the fluctuation deviation occurs, so as to better realize the switching of power supply.

[0030] It is worth noting that in step S1, the residual current value at any given time... The calculation formula is as follows: ; ; ; .

[0031] In the formula, the residual current value on the main power supply at a certain moment is... Three phase currents , , and the main power supply neutral line The vector and absolute values ​​of the residual current at a certain moment on the backup power supply. Three phase currents , , and the main power supply neutral line The vector and absolute value, Defined as comparing whether the solutions of multiple functions are the same. This represents the number of solutions to the corresponding function. It is a natural integer. This represents the function with the maximum number of solutions occurring within period T, where n is a quantifier that needs to be manually set, and period T is the acquisition period of the amplification unit. The residual current value at time tn. and The sampling period T and sampling time t are the same, and the curve in step S1 passes through the above residual current value. and The result obtained from the calculation.

[0032] It is worth noting that the data calculation is based on a large amount of laboratory data. Experiments have shown that the current will fluctuate irregularly, and fluctuations will also occur before a fault occurs. Therefore, in order to distinguish the above fluctuations and even to avoid faults, continuous residual current monitoring of the dual power supply is adopted, and timely reporting and switching are carried out when fluctuations occur on both sides or when a fault occurs on one side.

[0033] It is worth noting that, in this embodiment, if the sampling frequency of the sampling element is 2 times / s, the sampling time is...

[0034] With a sampling period of 0.5s and a sampling time T of 2 minutes, the main power supply and backup power supply will be sampled 240 times within the 2-minute period. The function calculates the instantaneous residual current values ​​at 240 time points. Of these 240 values ​​for the main power supply, 150 have a residual current value of 0.05A, i.e.

[0035] Of the 240 backup power supplies, 160 have a residual current of 0.04A, that is,

[0036] In progress Function comparison, that is,

[0037] Processing unit preferred The maximum, i.e., 160 units with the same current remaining value, are used as the power supply, and a signal is sent to drive the circuit breaker on the main power supply short circuit breaker to operate, when both sides... and When the values ​​are the same, the one with the smaller corresponding residual current value is preferred. For example, when , ,at this time .

[0038] It is worth noting that this embodiment uses a three-phase 4P, so the calculation of the residual current value is based on the vector sum of the three-phase currents and the neutral line. Alternatively, a three-phase 3P can be selected, in which case only the vector sum of the three-phase currents needs to be calculated.

[0039] It is worth noting that in the above calculations, the sampling period T of 2 minutes is positively correlated with the accuracy of the calculation results, and the accuracy of the current fluctuation of the two-sided power supply is... The calculation is as follows:

[0040] In the formula, 300 is the calibration value when switching between dual power supplies, and the unit of T is seconds. As the number of power supplies increases, the calibration value also increases. The calibration value is also related to the model of the sampling element.

[0041] In summary, this invention can continuously monitor the current value of a single power source and compare the residual current values ​​of two power sources. Even if they are not at the same time, the stability of both, i.e., the current fluctuation, can be calculated within the same time period. The most suitable power source can be selected for supply. Remote numerical control sharing can be achieved through communication units and conversion units, which can assist remote personnel in monitoring residual current. This invention does not exclude the application of current calculation when multiple power sources are supplied at the same time.

Claims

1. An improved residual current alarm method, comprising a signal processing device and multiple current transformers, characterized in that, The main power supply current transformer is used to obtain the residual current value on the three-phase main power supply line. The backup power current transformer is used to obtain the residual current value on the three-phase backup power line. , The signal processing device includes a current analysis unit and a power control unit. The current analysis unit calculates the current values ​​on the main power supply and the backup power supply, compares them with pre-stored current thresholds, and then drives the power control unit to shut down power supplies that do not meet the standards. The current analysis unit collects the residual current values ​​on the three-phase lines of the main and backup power supplies. and The specific data collection method includes the following steps: Step S1: The amplification unit compares the residual current collected within the acquisition period T. When the curves coincide, the data is sent to step S3; when the curves do not coincide, the data is sent to step S2. Step S2: Adjust the acquisition period T. By reducing the size of the period T, lock the boundary point of the curve and send the time of the boundary point to the alarm display unit in the current analysis unit. Step S3: Send the analog quantities of the curves that overlap within multiple periods to the conversion unit; Residual current value at any time The calculation formula is as follows: ； ； ； ； In the formula, the residual current value on the main power supply at a certain moment is... Three phase currents , , and the main power supply neutral line The vector and absolute values ​​of the residual current at a certain moment on the backup power supply. Three phase currents , , and the main power supply neutral line The vector and absolute value, Defined as comparing whether the solutions of multiple functions are the same. This represents the number of solutions to the corresponding function. It is a natural integer. This represents the function with the maximum number of solutions occurring within period T, where n is a quantifier that needs to be manually set, and period T is the acquisition period of the amplification unit. The residual current value at time tn. and The sampling period T and sampling time t are the same, and the curve in step S1 passes through the above residual current value. and The result obtained from the calculation.

2. The improved residual current alarm method according to claim 1, characterized in that, The current analysis unit includes an amplification unit, a conversion unit, a processing unit, and a signal output unit. After receiving the residual current signal, the amplification unit amplifies and outputs the signal, which is then sent to the conversion unit. The conversion unit converts the analog signal into a digital signal and sends it to the processing unit. The processing unit stores a current threshold value, and after comparison and judgment, the output unit outputs a drive signal.

3. The improved residual current alarm method according to claim 2, characterized in that, The power control unit includes an input unit, a control unit, and a drive unit. The input unit receives drive signals and sends them to the control unit. The control unit sends alarm signals and shutdown signals. After receiving the shutdown signal, the drive unit converts the digital signal into an analog signal and executes the circuit breaker to shut off the corresponding power supply.

4. The improved residual current alarm method according to claim 1, characterized in that, There is at least one backup power source.

5. An improved residual current alarm method according to claim 4, characterized in that, When the residual current value is not 0, the alarm display unit in the current analysis unit will operate.

6. The improved residual current alarm method according to claim 1, characterized in that, The alarm display unit sends the dynamic curve to the cloud via the communication unit.

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