Intelligent comprehensive protection device applied to low-voltage switch cabinet

Abstract

The utility model relates to the technical field of power equipment, and particularly discloses an intelligent comprehensive protection device applied to a low-voltage switch cabinet, which comprises a power supply circuit, an analog quantity input circuit, a switching value input and relay output circuit and a communication circuit, the power supply circuit, the analog quantity input circuit, the switching value input and relay output circuit and the communication circuit are all connected to the MCU, the analog quantity input circuit is used for collecting voltage, current and temperature information, the switching value input and relay output circuit is used for inputting and outputting different signals in various working modes, and the communication circuit is used for transmitting operation data. According to the utility model, collection of conventional analog quantity information is satisfied, remote signaling, remote measurement, remote control and remote regulation intelligentization demands are satisfied, the integration level is high, the line is simplified, and the difficulty of fault and abnormity troubleshooting of power distribution equipment is low. And the dual-power mode can also ensure that the MCU can be normally used under the condition that the bus is powered off.

Description

Technical Field

[0001] The utility model relates to the technical field of electric power equipment, in particular to an intelligent comprehensive protection device applied to a low-voltage switch cabinet. Background Art

[0002] Switchgear is an electrical device whose main function is to open and close, control and protect electrical equipment in the process of power generation, transmission, distribution and energy conversion in the power system. Intelligent power distribution is the inevitable direction of energy digital development. Traditional low-voltage switchgear usually has independent multi-function instruments, circuit breaker electronic releases, motor protectors, etc. Figure 1 As shown, the instrument is equipped with current, voltage, switch input, and relay output interfaces; the external current transformer and voltage signal are connected to the multi-function instrument to realize the functions of current, voltage, power, frequency, electricity, harmonics, and status acquisition. The auxiliary contacts and alarm contacts of the circuit breaker are connected to the switch input interface of the instrument to realize the remote signaling function; the data is communicated to the intelligent power distribution edge system through the communication interface of the multi-function instrument. The power distribution protection function is still independently realized by the traditional molded case circuit breaker. For the motor circuit, a motor protector will also be configured to realize the signal acquisition and protection control of the contactor. The power distribution protection and motor protection are independently configured with protection-level current transformers to realize the protection function.

[0003] The disadvantages of this solution are low functional integration, complex secondary principles and circuits; the primary circuit of the switch cabinet manufacturing process is complex, with many connection points and many connections between sensors, resulting in a high risk of failure; the operation and maintenance of the switch cabinet after a failure occurs during operation is difficult and takes a long time to repair; the protection of circuit breakers and motor protectors usually does not have communication functions, and detailed protection data cannot be monitored. Utility Model Content

[0004] In order to improve the defects of low integration and complex circuits of switch cabinets in the prior art, an intelligent comprehensive protection device applied to low-voltage switch cabinets is provided to simplify the structure and improve the operating safety of the switch cabinets.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] An intelligent integrated protection device for low-voltage switchgear includes a power supply circuit, an analog input circuit, a switch input and relay output circuit, and a communication circuit. The power supply circuit, the analog input circuit, the switch input and relay output circuit, and the communication circuit are all connected to an MCU. The analog input circuit is used to collect voltage, current and temperature information. The switch input and relay output circuit is used to input and output different signals in multiple working modes. The communication circuit is used to transmit operating data.

[0007] In the above scheme, the analog input circuit can realize the collection of current, voltage and temperature information to meet the conventional analog quantity collection of the switch cabinet; the switch input and relay output circuit can realize the input and output of different signals under multiple working modes, that is, one circuit meets the application requirements of multiple modes, and there is no need to configure corresponding independent components for different modes, which greatly simplifies the system structure and reduces the circuit complexity, and can also reduce the size of the circuit board; the communication circuit can realize the internal and external transmission of operating data, upload monitoring data, and realize intelligent monitoring.

[0008] According to the embodiment, the analog input circuit includes three voltage sampling ports, which are respectively connected to the A-phase, B-phase, and C-phase primary plug-ins on the incoming line side of the outgoing line loop, and connected to the MCU after passing through the protection fuse. In this solution, the voltage information of the A-phase, B-phase, and C-phase can be collected respectively through the three voltage sampling ports to realize complete voltage information monitoring.

[0009] According to the embodiment, the analog input circuit includes a current sampling port, which includes three metering current sampling ports, three protection current sampling ports and one leakage current sampling port. The three metering current sampling ports are respectively connected to the output sides of three metering-grade current transformers, the three protection current sampling ports are respectively connected to the output sides of three protection-grade current transformers, and the leakage current sampling port is connected to the current transformer of the external residual current or grounding protection. In this solution, not only metering current and protection current sampling are realized, but also leakage current sampling is realized, which can effectively ensure the safety and reliability of the switch cabinet operation.

[0010] According to the embodiment, the analog input circuit includes six temperature sampling ports, which are respectively connected to six temperature sensors, of which three temperature sampling ports are respectively led to the primary plug-ins of the incoming line side A phase, B phase, and C phase of the outgoing line loop, and are laid in parallel with the voltage sampling port; the other three temperature sampling ports are installed on the primary plug-in of the outgoing line pile head. In this solution, the temperature of the incoming line side and the temperature of the outgoing line side are collected at the same time, and the temperature sampling points are more abundant, providing more sufficient data for temperature monitoring; in addition, the temperature sampling port on the incoming line side is laid in parallel with the voltage sampling port, which can greatly simplify the circuit structure.

[0011] According to the embodiment, the switch input and relay output circuit includes four passive switch input ports and three relay output ports, one of which is a 220V active port, and the other two are passive relay output ports. In this solution, the switch input and relay output circuit can realize multiple working mode conversions through only four passive switch input ports and three relay output ports, and realize power distribution protection function, motor protection function, motor forward and reverse start function, and motor high and low speed start function, with a simple structure but powerful functions.

[0012] According to an embodiment, the communication circuit includes three RS485 communication interfaces, one of which is used to connect to a local display unit, and the other two RS485 communication interfaces are used to transmit operating data.

[0013] According to the embodiment, the power supply circuit includes an internal power supply circuit and an external power supply circuit, and the MCU is connected to the internal power supply circuit and the external power supply circuit at the same time. In this solution, the internal power supply and the external power supply are arranged at the same time to power the MCU. When the internal power supply is powered off, the external power supply can be enabled to ensure the normal operation of the MCU and the normal transmission of monitoring data, providing technical guarantee for ensuring the continuous and safe operation of the switch cabinet.

[0014] According to the embodiment, an extended terminal circuit is also included, and the extended terminal circuit supports 1 active fire protection non-input signal. In this solution, by setting the extended terminal current to access the fire protection signal, the circuit breaker will trip when the external fire protection signal is input, thereby ensuring the safe operation of the switch cabinet.

[0015] Compared with the prior art, the utility model has the following beneficial effects:

[0016] The intelligent module circuit not only meets the basic functions of all information collection of conventional low-voltage power distribution circuits, but also meets the intelligent needs of remote signaling, remote measurement, remote control, and remote adjustment. It has a high degree of integration, simpler circuits, and less difficulty in troubleshooting distribution equipment failures and abnormalities, which can improve maintenance efficiency.

[0017] The dual-power parallel power supply solution can work normally even when the busbar is without power, which solves the problem that the intelligent module needs a large protective power supply capacity and high reliability as a trip device, and also meets the continuity requirement of uninterrupted power supply for the internal self-use of the intelligent module. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 The following is an implementation architecture diagram of an intelligent low-voltage switchgear in the prior art.

[0020] Figure 2a , Figure 2b , Figure 2c , Figure 2d Together, the structure of the intelligent integrated protection device applied to the low-voltage switch cabinet in the embodiment of the utility model is demonstrated. DETAILED DESCRIPTION

[0021] The technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, rather than all the embodiments. The components of the embodiment of the utility model generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiment of the utility model provided in the drawings is not intended to limit the scope of the utility model claimed for protection, but merely represents the selected embodiment of the utility model. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the utility model.

[0022] It should be noted that, since the structural circuit diagram of the intelligent integrated protection device applied to the low-voltage switch cabinet in this embodiment is relatively large, it is divided into four small diagrams for display, such as Figure 2a , Figure 2b , Figure 2c , Figure 2d As shown, serial numbers 1 to 34 in the figure represent truncated breakpoints respectively, and two breakpoints with the same serial number represent two truncated breakpoints of the same cable. By marking the serial numbers, it is convenient to restore it to a circuit diagram.

[0023] Please refer to Figure 2a , Figure 2b , Figure 2c , Figure 2d The intelligent integrated protection device for low-voltage switchgear provided in this embodiment includes an analog input circuit, a switch input and relay output circuit, and a communication circuit. The analog input circuit, the switch input and relay output circuit, and the communication circuit are all connected to the MCU.

[0024] The analog input circuit includes a voltage sampling port, a current sampling port and a temperature sampling port.

[0025] Please refer to Figure 2a , Figure 2b There are three voltage sampling ports, which are respectively led to the primary plug-in connection of phase A, phase B, and phase C on the incoming side of the outgoing line circuit, and connected to the MCU after passing through the protection fuse to realize the incoming three-phase voltage monitoring function.

[0026] Please refer to the figure Figure 2bThe current sampling port includes three metering current sampling ports, three protection current sampling ports and one leakage current sampling port. The three metering current sampling ports are respectively connected to the output sides of three metering-grade current transformers, and the three protection current sampling ports are respectively connected to the output sides of three protection-grade current transformers. The metering-grade current transformer is used to monitor the three-phase current under normal operation, and the protection-grade current transformer is used to monitor the current in the circuit overload or short-circuit fault state, and then drive the circuit breaker or contactor to trip and disconnect the fault current. The leakage current sampling port is connected to the current transformer of the external residual current or grounding protection, which is used to monitor the vector sum of the three-phase current of the circuit, realize the leakage current alarm and grounding protection functions, and the current transformer is installed on the outgoing side of the circuit.

[0027] Please refer to Figure 2b There are six temperature sampling ports, each connected to six temperature sensors. Three of the temperature sampling ports are located at the same position as the incoming voltage sampling to simplify the structural design of the sampling point and keep them laid in parallel with the voltage sampling port; the other three temperature sampling ports are installed on the primary plug-in of the outgoing pile head. The six temperature sampling ports realize the temperature monitoring function of the six key connection points of the primary circuit. By arranging six temperature sensors at different positions, the temperature monitoring of important key points can be realized, improving the safety and reliability of the entire system.

[0028] Please refer to Figure 2b , Figure 2c , the switch input and relay output circuit includes four passive switch input ports (DI1, DI2, DI3, DI4) and three relay output ports (DO1, DO2, DO3), one of which is a 220V active port, and the other two are passive relay output ports. Each port function is connected to the external input or output signal according to the set working mode. As an example of an implementable method, the default input and output definitions corresponding to the specific working mode are as follows:

[0029] (1) Power distribution protection mode

[0030] DI1 is the auxiliary contact for the circuit breaker opening and closing states, and is connected to the normally open contact by default;

[0031] DI2 is the circuit breaker fault trip alarm contact, which is connected to the normally open contact by default;

[0032] DI3 is the energy storage ready state contact of the circuit breaker electric operating mechanism, which is connected to the normally open contact by default;

[0033] DI4 is a spare input port and can be used for access to special signal nodes in the power distribution circuit.

[0034] DO1 is the circuit breaker shunt trip drive output. When a fault current occurs in the circuit, it outputs a signal to disconnect the circuit breaker. The default is DV220V active output.

[0035] DO2 is the electric remote control closing output, which is a passive dry contact by default. The A phase and N phase introduced by voltage sampling can be used as power supply;

[0036] DO3 is the electric remote control trip output, which is a passive dry contact by default. The A phase and N phase introduced by voltage sampling can be used as power supply.

[0037] (2) Motor protection direct start mode

[0038] DI1 is the auxiliary contact for the circuit breaker opening and closing states, and is connected to the normally open contact by default;

[0039] DI2 is the circuit breaker fault trip alarm contact, which is connected to the normally open contact by default;

[0040] DI3 is the auxiliary contact of the contactor, which is connected to the normally open contact by default;

[0041] DI4 is a spare input port and can be used for access to special signal nodes in the power distribution circuit.

[0042] DO1 is the circuit breaker shunt trip drive output. When a short-circuit fault current occurs in the circuit, a signal is output to disconnect the circuit breaker. The default is DV220V active output.

[0043] DO2 is the start contactor control output, which is a passive dry contact by default. Phase A and phase N introduced through voltage sampling can be used as power supply. When a small current fault such as overload or stall occurs in the circuit, a signal is output to disconnect the contactor.

[0044] DO3 is the standby relay output port.

[0045] (3) Motor protection forward and reverse starting mode

[0046] DI1 is the auxiliary contact for the circuit breaker opening and closing states, and is connected to the normally open contact by default;

[0047] DI2 is the circuit breaker fault trip alarm contact, which is connected to the normally open contact by default;

[0048] DI3 is the auxiliary contact of the forward contactor, which is connected to the normally open contact by default;

[0049] DI4 is the auxiliary contact of the reversing contactor, which is connected to the normally open contact by default;

[0050] DO1 is the circuit breaker shunt trip drive output. When a short-circuit fault current occurs in the circuit, a signal is output to disconnect the circuit breaker. The default is DV220V active output.

[0051] DO2 is the control output of the forward contactor. It is a passive dry contact by default. Phase A and phase N introduced through voltage sampling can be used as power supply. When a small current fault such as overload or stall occurs during the forward process of the loop, a signal is output to disconnect the forward contactor.

[0052] DO3 is the reversing contactor control output. It is a passive dry contact by default. Phase A and phase N introduced through voltage sampling can be used as power supply. When a small current fault such as overload or stall occurs during the reversing process of the circuit, a signal is output to disconnect the reversing contactor.

[0053] (4) Motor protection high and low speed starting modes

[0054] DI1 is the auxiliary contact for the circuit breaker opening and closing states, and is connected to the normally open contact by default;

[0055] DI2 is the circuit breaker fault trip alarm contact, which is connected to the normally open contact by default;

[0056] DI3 is the auxiliary contact of the low-speed contactor, which is connected to the normally open contact by default;

[0057] DI4 is the auxiliary contact of the high-speed contactor, which is connected to the normally open contact by default;

[0058] DO1 is the circuit breaker shunt trip drive output. When a short-circuit fault current occurs in the circuit, a signal is output to disconnect the circuit breaker. The default is DV220V active output.

[0059] DO2 is the low-speed contactor control output. It is a passive dry contact by default. Phase A and phase N introduced through voltage sampling can be used as power supply. When a small current fault such as overload or stall occurs during the low-speed operation of the circuit, a signal is output to disconnect the low-speed contactor.

[0060] DO3 is the high-speed contactor control output. It is a passive dry contact by default. Phase A and phase N introduced through voltage sampling can be used as power supply. When a small current fault such as overload or stall occurs during high-speed operation of the circuit, a signal is output to disconnect the high-speed contactor.

[0061] In this embodiment, the switch input and relay output circuit can realize multiple working mode conversions through only four passive switch input ports and three relay output ports, and realize power distribution protection function, motor protection function, motor forward and reverse start function, and motor high and low speed start function, with a simple structure but powerful functions. That is, the utility model integrates multiple protection functions that are respectively realized by independent devices in the traditional low-voltage switch cabinet, and jointly uses the data collected by the analog input circuit to execute the corresponding protection strategy, without the need to configure sensors for each protection device separately, thereby greatly simplifying the system structure and line layout.

[0062] Please refer to the figure Figure 2bThe communication circuit includes three RS485 communication interfaces, which are defined as communication interface 1, communication interface 2, and communication interface 3. Communication interface 1 is used to connect the local display unit, and is connected in parallel with the DC24V power port to provide power for the display unit. Communication interface 1 is mainly used for setting various parameters and working modes, and displaying local operation data information. Communication interface 2 is used for networking of the local intelligent power distribution monitoring system, and transmits the operation data to the intelligent power distribution system. Communication interface 3 is used for networking of the external power monitoring system, and transmits the operation data to the power monitoring system. Communication interface 3 supports an external RS485 to RJ45 converter to convert the Modbus-RTU protocol to the Modbus-TCP protocol.

[0063] In this embodiment, the intelligent module circuit also includes an extended terminal circuit, which supports 1 DC24V active fire protection non-input signal. When an external fire protection signal is input, the circuit breaker will trip and the circuit breaker trip signal will be fed back to the fire protection system through 4 extended terminals. The fire protection feedback signal defaults to a normally closed signal.

[0064] The expansion terminal circuit also reserves 2 expansion terminals for the access of custom functions, including external control power input, open node signal output and other functions.

[0065] In this embodiment, the power supply circuit includes an external power supply circuit and an internal power supply circuit. The dual power supply mode ensures that the intelligent module can work normally even when the main bus is without power.

[0066] Please refer to Figure 2a , Figure 2b The internal power supply circuit includes a DC 220V power supply and a DC 24V power supply. The three-phase four-wire AC220V of the A phase, B phase, and C phase of the incoming line side is introduced through the voltage sampling ports UA, UB, and UC. On the one hand, the DC 220V power supply is rectified to DC220V and then directly introduced to the drive circuit DV+ and DV- terminals. On the other hand, the DC 24V power supply is rectified to DC24V to power the intelligent module MCU. The external 24V can be centrally powered by a UPS power supply or two transformer outlets through an AC220V / DC24V switching power supply to ensure the reliability of the external power supply. The three-phase four-wire AC220V is directly introduced through the voltage sampling port to achieve the reuse of the voltage sampling port, simplify the port design and reduce the complexity of wiring.

[0067] Please refer to the figure Figure 2d The external power supply circuit includes one or more sets of DC 24V switching power supplies, which are distributed in series through the power bus and introduced into each circuit. After this external power supply is connected in parallel with the internal DC 24V power supply, it provides external continuous power supply for the MCU.

[0068] The intelligent module circuit of this embodiment not only meets the basic functions of all information collection of conventional low-voltage distribution circuits, but also meets the intelligent requirements of remote signaling, remote measurement, remote control, and remote adjustment. It has high integration, simpler circuits, and less difficulty in troubleshooting distribution equipment failures and abnormalities, thereby improving maintenance efficiency.

[0069] The power supply circuit in this embodiment has the following advantages: the three-phase AC220 / DC220V drive power rectifier module with a power of 200W is highly mature, simple in circuit, highly reliable and small in size; as long as one phase of the three-phase voltage is normal, the power supply can work normally, meeting the normal operation of the power distribution system under abnormal conditions such as phase loss; the internal power supply and voltage sampling and temperature use the same location to introduce the intelligent module, reducing the complexity of the circuit and improving the production efficiency; the external DC24V power supply can ensure that the MCU can still work normally when the main bus is without power;

[0070] The working status of the two power supplies can be uploaded in real time via communication. When one power supply fails, the system will generate an alarm, and the operation and maintenance personnel can quickly troubleshoot the problem.

[0071] The above description is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention.

Claims

1. An intelligent integrated protection device applied to a low voltage switch cabinet, characterized in that: It includes a power supply circuit, an analog input circuit, a switch input and relay output circuit, and a communication circuit. The power supply circuit, the analog input circuit, the switch input and relay output circuit, and the communication circuit are all connected to the MCU. The analog input circuit is used to collect voltage, current and temperature information. The switch input and relay output circuit is used for input and output of different signals in multiple working modes. The communication circuit is used to transmit operation data.

2. The intelligent integrated protection device for low-voltage switch cabinet according to claim 1 is characterized in that: The analog input circuit includes three voltage sampling ports, which are respectively connected to the A-phase, B-phase, and C-phase primary plug-ins on the incoming side of the outgoing line loop, and are connected to the MCU after passing through the protection fuse.

3. The intelligent integrated protection device for low-voltage switch cabinet according to claim 1 is characterized in that: The analog input circuit includes a current sampling port, which includes three metering current sampling ports, three protection current sampling ports and one leakage current sampling port. The three metering current sampling ports are respectively connected to the output sides of three metering-grade current transformers, the three protection current sampling ports are respectively connected to the output sides of three protection-grade current transformers, and the leakage current sampling port is connected to an external residual current or grounding protection current transformer.

4. The intelligent integrated protection device for low voltage switch cabinet according to claim 2 is characterized in that: The analog input circuit includes six temperature sampling ports, which are respectively connected to six temperature sensors. Three of the temperature sampling ports are respectively led to the A-phase, B-phase, and C-phase primary plug-ins on the incoming side of the outgoing line loop and are laid in parallel with the voltage sampling port; the other three temperature sampling ports are installed on the primary plug-in of the outgoing line pile.

5. The intelligent integrated protection device for low voltage switch cabinet according to claim 1 is characterized in that: The switch input and relay output circuit includes four passive switch input ports and three relay output ports, one of which is a 220V active port and the other two are passive relay output ports.

6. The intelligent integrated protection device for low-voltage switch cabinet according to claim 1 is characterized in that: The communication circuit includes three RS485 communication interfaces, one of which is used to connect to the local display unit, and the other two RS485 communication interfaces are used to transmit operation data.

7. The intelligent integrated protection device for low-voltage switch cabinet according to any one of claims 1 to 6, characterized in that: The power supply circuit includes an internal power supply circuit and an external power supply circuit, and the MCU is connected to the internal power supply circuit and the external power supply circuit at the same time.

8. The intelligent integrated protection device for low-voltage switch cabinet according to claim 7 is characterized in that: The internal power supply circuit includes a DC 220V power supply and a DC 24V power supply. The three-phase four-wire AC220V on the incoming line side is introduced into the DC 220V power supply and the DC 24V power supply respectively through the voltage sampling port. The DC 220V power supply is connected to the MCU and the circuit breaker, and the DC 24V power supply is connected to the MCU.

9. The intelligent integrated protection device for low-voltage switch cabinet according to claim 8, characterized in that: The external power supply circuit includes a DC 24V switching power supply, and the DC 24V switching power supply is connected to the MCU.

10. The intelligent integrated protection device for low voltage switch cabinet according to claim 1, characterized in that: It also includes an extended terminal circuit, which supports 1-way active fire protection non-input signal.

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