A new topology recognition system transmitter

Abstract

The invention discloses a transmitting end of a novel topology identification system, and relates to the technical field of transmitting ends of power grid topology systems, comprising a power supply module and a zero-crossing detection module, a system control module, a driving module, a frequency switch module and a load which are connected in sequence, wherein the input end of the zero-crossing detection module is connected to the power grid, the zero-crossing detection module is used to detect the zero-crossing point of the power grid voltage, the system control module triggers a PWM wave according to the zero-crossing point, the frequency switch module is connected in series with the corresponding load, the frequency switch module is a controllable switch tube with frequency switching capability, the driving module controls the on-off of the frequency switch module according to the PWM wave, so as to control the loading / releasing of each load to generate a specific frequency waveform, the output end of the load is connected to the power grid and sends the specific frequency waveform to the power grid, so that the power grid topology system can effectively obtain the topology identification structure in the power network, and bring great convenience to the power network management.

Description

Technical Field

[0001] The invention relates to the technical field of a transmitter of a power grid topology system, in particular to a transmitter of a novel topology identification system. Background Art

[0002] In the early stage of power grid development, the scale of power grid was small, the number of equipment was limited, the number of branches was relatively small, and the management was not difficult. With the continuous expansion of the power grid system, the branches have become complicated. In addition, many power grid branches in the past have not been effectively registered and managed, resulting in the interweaving of new and old branches in many areas, making it impossible to know the real power grid system, which has caused great difficulty in power network management. Therefore, the transmitter of the new topology identification system came into being. Summary of the invention

[0003] In response to the above problems and technical requirements, the inventors have proposed a new type of topology identification system sending end. The power grid topology system can effectively obtain the topology identification structure in the power network through the topology identification device at the sending end, which greatly facilitates the power network management.

[0004] The technical solution of the present invention is as follows:

[0005] A transmitting end of a novel topology identification system includes a power supply module and a zero-crossing detection module, a system control module, a drive module, a frequency switch module and a load which are connected in sequence. The input end of the zero-crossing detection module is connected to the power grid. The zero-crossing detection module is used to detect the zero-crossing point of the power grid voltage. The system control module triggers a PWM wave according to the zero-crossing point. The frequency switch module is connected in series with the corresponding load. The frequency switch module is a controllable switch tube with frequency switching capability. The drive module controls the on-off of the frequency switch module according to the PWM wave so as to control the loading / unloading of each load to generate a specific frequency waveform. The output end of the load is connected to the power grid and sends a specific frequency waveform to the power grid.

[0006] The transmitting end also includes a communication module and a signal indicator light group respectively connected to the system control module. The system control module is connected to the external port through the communication module, and the transmitting end performs firmware upgrades, system debugging and fixed waveform settings through the communication module; the signal indicator light group is used to indicate the working status of each module of the transmitting end.

[0007] Its further technical solution is that the zero-crossing detection module includes an optical coupler, multiple diodes, resistors and capacitors, the anode of the first diode is connected to the live wire of the power grid, the anode of the second diode is connected to the neutral wire of the power grid, the cathodes of the first diode and the second diode are both grounded through three-stage series resistors, the anode end of the light emitter of the optical coupler is connected to the common end of the second-stage resistor and the third-stage resistor through a fourth resistor, the anode end of the light emitter of the optical coupler is also connected to the first end of the fifth resistor and the first end of the first capacitor respectively, the first output end of the light receiver of the optical coupler is connected to the system control module as a zero point acquisition end after passing through a sixth resistor, and the second end of the fifth resistor, the second end of the first capacitor and the second output end of the light receiver of the optical coupler are all grounded;

[0008] The grid voltage is phase-flipped after passing through the first diode and the second diode, and enters the optocoupler after being divided by three-stage series resistors. When the voltage at the first output terminal of the optocoupler is higher than the conduction voltage drop of the optocoupler, the zero-point acquisition terminal changes from a high level to a low level, thereby realizing the zero-point detection of the grid voltage.

[0009] Its further technical solution is that the frequency switch module is implemented based on the IGBT module, the load is implemented based on the load resistor, the input end of the driver is connected to the PWM wave output by the system control module, the output end of the driver is connected to the gate level of the IGBT module through the seventh resistor and the eighth resistor in sequence, the collector of the IGBT module is connected to the power grid branch through the load resistor, and the emitter of the IGBT module is grounded through the ninth resistor.

[0010] Its further technical solution is that the communication module includes an RS485 chip and an RS232 chip, which are respectively connected to corresponding communication interfaces of the system control module, the RS485 chip is implemented based on the SIT485BD chip, and the RS232 chip is implemented based on the ST232ECDR chip.

[0011] Its further technical solution is that the signal indicator light group includes seven groups of signal indication circuits; the first signal indication circuit is used to indicate the working condition of the system control module; the second signal indication circuit is used to indicate the working condition of the zero-crossing detection module, and displays whether the zero-crossing point of the grid voltage is detected normally; the third signal indication circuit is used to indicate the working condition of the drive module, and displays whether the PWM wave is sent normally; the fourth signal indication circuit and the fifth signal indication circuit are used to indicate the working condition of the RS485 chip in the communication module, the fourth signal indication circuit is used for data reception indication, and the fifth signal indication circuit is used for data transmission indication; the sixth signal indication circuit and the seventh signal indication circuit are used to indicate the working condition of the RS232 chip in the communication module, the sixth signal indication circuit is used for data reception indication, and the seventh signal indication circuit is used for data transmission indication;

[0012] The circuit structures of the signal indication circuits are the same, including LEDs and a tenth resistor, and the LEDs are connected in a common cathode manner; in the first signal indication circuit, the LED anode is connected to the I / O port of the system control module, and the LED cathode is grounded through the tenth resistor.

[0013] Its further technical solution is that the system control module is implemented based on the STM32L431CBT6 chip.

[0014] The beneficial technical effects of the present invention are:

[0015] The zero-crossing detection module, system control module, drive module, frequency switch module, load and power grid of the present application form a closed-loop circuit. The system control module generates PWM waves of different frequency bands according to the zero-crossing point of the power grid voltage detected by the zero-crossing detection module. The drive module controls the on and off of the frequency switch module according to the PWM wave, so as to control the loading / unloading of each load to generate a specific frequency waveform. The load sends the specific frequency waveform to the power grid, so that the power grid topology system can effectively obtain the topology identification structure in the power network, which brings great convenience to the power network management; by providing a communication module with two communication modes, the sending end can cope with different communication processing places, which is convenient for the sending end to upgrade the firmware, debug the system and set the fixed waveform; by setting the signal indicator light group, it is convenient for the operator to understand whether each module of the sending end is working normally. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a block diagram of the transmitter principle provided by this application.

[0017] Figure 2 This is the chip pin diagram of the system control module provided in this application.

[0018] Figure 3 It is a circuit diagram of the zero-crossing detection module provided in this application.

[0019] Figure 4 This is a connection circuit diagram of the drive module, frequency switch module and load provided in this application.

[0020] Figure 5 It is a schematic diagram of the communication module provided in this application.

[0021] Figure 6 It is a circuit diagram of the signal indicator light group provided in this application. DETAILED DESCRIPTION

[0022] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0023] The present application discloses a novel topology identification system transmitting end, which is mainly used in the transmitting end of the power grid topology system of low voltage lines. Figure 1 As shown, it includes a power supply module and a zero-crossing detection module, a system control module, a drive module, a frequency switch module and a load connected in sequence. The input end of the zero-crossing detection module is connected to the power grid. The zero-crossing detection module is used to detect the zero-crossing point of the power grid voltage. The system control module triggers the PWM wave according to the zero-crossing point, that is, according to the different number of zero-crossing points, the system control module will send PWM waves of different frequency bands, so that multiple desired harmonic waveforms of different frequency bands are generated in the power grid, which is helpful for the judgment when collecting harmonic signals, so that the sending end has a certain anti-interference ability. The frequency switch module is connected in series with the corresponding load, and the frequency switch module is a controllable switch tube with frequency switching capability, such as an IGBT module, a MOS tube, etc. The drive module controls the on and off of the frequency switch module according to the PWM wave, so as to control the load / load of each load to generate a specific frequency waveform, and the output end of the load is connected to the power grid and sends a specific frequency waveform to the power grid. The zero-crossing detection module, system control module, drive module, frequency switch module, load and power grid of the present application form a closed-loop circuit. Passive signal injection is used for the signal injection method in the power network. Any waveform signal within a specific range can be sent to the power grid through the sending end. The power grid topology system can effectively obtain the topology identification structure in the power network, which brings great convenience to the power network management.

[0024] The power module of the present application includes an AC-DC converter, a DC-DC converter, a voltage stabilizer, etc., all of which are built using existing modules and will not be described in detail here. The power module is used to power the remaining modules of the transmitting end.

[0025] The system control module of this application is implemented based on the STM32L431CBT6 chip. The chip pin diagram is as follows Figure 2 As shown, the system control module provides signal control logic, data conversion processing, working condition detection and judgment, output PWM waveform control, signal indication control, communication with external ports and debugging data transmission for the entire transmitter operation.

[0026] The grid voltage is generally transmitted in the form of a sine wave. The zero-crossing detection module monitors the zero-crossing point of the sine wave and determines the phase angle position of the AC sine wave. The circuit diagram of the zero-crossing detection module is shown in Figure 3As shown, it includes an optocoupler U1, multiple diodes, resistors and capacitors, and the optocoupler U1 is implemented based on the HCNW137-500E model. The anode of the first diode D1 is connected to the live wire L of the power grid, the anode of the second diode D2 is connected to the neutral wire N of the power grid, and the cathodes of the first diode D1 and the second diode D2 are grounded through three series resistors (i.e., R1, R2, and R3). The anode terminal pin 2 of the light emitter of the optocoupler U1 is connected to the common end of the second-stage resistor R2 and the third-stage resistor R3 through the fourth resistor R4. The anode terminal pin 2 of the light emitter of the optocoupler U1 is also connected to the first end of the fifth resistor R5 and the first end of the first capacitor C1 respectively. The first output terminal pin 7 of the light receiver of the optocoupler U1 is connected to the system control module as the zero point acquisition terminal zero through the sixth resistor R6. The second end of the fifth resistor R5, the second end of the first capacitor C1, and the second output terminal pin 6 of the light receiver of the optocoupler U1 are all grounded.

[0027] The grid voltage is phase-flipped through the first diode D1 and the second diode D2, so that the AC sine wave is in the positive half cycle, and enters the optocoupler U1 after being divided by three-stage series resistors. When the voltage of the first output pin 7 of the optocoupler U1 is higher than the conduction voltage drop of the optocoupler U1, the zero-point acquisition terminal zero changes from a high level to a low level, thereby realizing the zero-crossing detection of the grid voltage.

[0028] The circuit diagram of the drive module is as follows Figure 4 As shown, it includes a driver U2, a frequency switch module based on an IGBT module T, and a load based on a load resistor, wherein the driver U2 is based on the HCPL-3120-500E model, and the IGBT module T is based on the FGH50T65SQD-F155 model. The input pin ANODE of the driver U2 is connected to the PWM wave output by the pin MCU_PWM of the system control module, and the output pin VO1 of the driver U2 is connected to the gate level of the IGBT module T through the seventh resistor R7 and the eighth resistor R8 in sequence, the collector of the IGBT module T is connected to the power grid branch through the load resistor R, and the emitter of the IGBT module T is grounded through the ninth resistor R9.

[0029] The driver U2 can make the IGBT module T in a fully on state to reduce the internal resistance of the tube, avoid overheating and damage, and ensure the stable operation of the transmitter. The driver U2 processes the PWM wave to obtain a switch drive signal, and the IGBT module T is turned on or off according to the switch drive signal, so that the load resistor R continuously forms a load / release in the power grid, generating a specific frequency waveform (that is, a power grid harmonic waveform).

[0030] The transmitter also includes a communication module and a signal indicator light group connected to the system control module respectively. The system control module is connected to an external port (such as a PC or other communication equipment) through the communication module. The transmitter performs firmware upgrades, system debugging, and fixed waveform settings through the communication module. The schematic diagram of the communication module is shown in Figure 5 As shown, it includes an RS485 chip and an RS232 chip, which are respectively connected to the corresponding communication interface TX / RX of the system control module. The RS485 chip is implemented based on the SIT485BD chip, and the RS232 chip is implemented based on the ST232ECDR chip. The communication module using two communication modes enables the sending end to cope with different communication processing places.

[0031] The signal indicator light group is used to indicate the working status of each module at the sending end. The signal indicator light group includes seven groups of signal indication circuits. The circuit diagram is as follows: Figure 6 As shown, the first signal indication circuit (corresponding to LED1) is used to indicate the working status of the system control module. When the system control module is turned on, it will perform an internal operation self-check. This function is mainly to check whether the program operation status is normal. The second signal indication circuit (corresponding to LED2) is used to indicate the working status of the zero-crossing detection module, and display whether the zero-crossing point of the grid voltage is detected normally. The third signal indication circuit (corresponding to LED3) is used to indicate the working status of the drive module, and display whether the PWM wave is sent normally. The fourth signal indication circuit (corresponding to LED4) and the fifth signal indication circuit (corresponding to LED5) are used to indicate the working status of the RS485 chip in the communication module. The fourth signal indication circuit is used for data reception indication, and the fifth signal indication circuit is used for data transmission indication. The sixth signal indication circuit (corresponding to LED6) and the seventh signal indication circuit (corresponding to LED7) are used to indicate the working status of the RS232 chip in the communication module. The sixth signal indication circuit is used for data reception indication, and the seventh signal indication circuit is used for data transmission indication.

[0032] The circuit structures of the various signal indication circuits are the same, and all include an LED and a tenth resistor R10, and the LEDs are connected in a common cathode manner. In the first signal indication circuit, the anode of LED1 is connected to the I / O port of the system control module, and the cathode of LED1 is grounded through the tenth resistor R10. Optionally, the present application does not limit the indication state of the signal indicator light group, as long as it is possible to distinguish whether the working state of each module is normal, such as a red LED light indicates that the corresponding module is abnormal, a green LED light indicates that the module is normal, or a LED that is always on indicates that the corresponding module is normal, and a flashing LED indicates that the module is abnormal.

[0033] The above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A transmitting end of a topology identification system, characterized in that: It comprises a power supply module and a zero-crossing detection module, a system control module, a driving module, a frequency switch module and a load which are connected in sequence, wherein the input end of the zero-crossing detection module is connected to the power grid, the zero-crossing detection module is used to detect the zero-crossing point of the power grid voltage, the system control module triggers a PWM wave according to the zero-crossing point, the frequency switch module is connected in series with the corresponding load, the frequency switch module is a controllable switch tube with frequency switching capability, the driving module controls the on-off of the frequency switch module according to the PWM wave, so as to control the loading / releasing of each load to generate a specific frequency waveform, and the output end of the load is connected to the power grid and sends the specific frequency waveform to the power grid; The transmitting end further comprises a communication module and a signal indicator light group respectively connected to the system control module, the system control module is connected to an external port through the communication module, and the transmitting end performs firmware upgrade, system debugging and fixed waveform setting through the communication module; the signal indicator light group is used to indicate the working status of each module of the transmitting end; The zero-crossing detection module includes an optocoupler, a plurality of diodes, a resistor and a capacitor, wherein the anode of the first diode is connected to the live wire of the power grid, the anode of the second diode is connected to the neutral wire of the power grid, the cathodes of the first diode and the second diode are both grounded through three-stage series resistors, the anode end of the light emitter of the optocoupler is connected to the common end of the second-stage resistor and the third-stage resistor through a fourth resistor, the anode end of the light emitter of the optocoupler is also respectively connected to the first end of the fifth resistor and the first end of the first capacitor, the first output end of the light receiver of the optocoupler is connected to the system control module as a zero point acquisition end through a sixth resistor, and the second end of the fifth resistor, the second end of the first capacitor and the second output end of the light receiver of the optocoupler are all grounded; The grid voltage is phase-flipped through the first diode and the second diode, and enters the optocoupler after voltage division through the three-stage series resistor. When the voltage at the first output terminal of the optocoupler is higher than the conduction voltage drop of the optocoupler, the zero-point acquisition terminal changes from a high level to a low level, thereby realizing zero-point detection of the grid voltage. The driving module includes a driver, the frequency switch module is implemented based on an IGBT module, the load is implemented based on a load resistor, the input end of the driver is connected to the PWM wave output by the system control module, the output end of the driver is connected to the gate level of the IGBT module through a seventh resistor and an eighth resistor in sequence, the collector of the IGBT module is connected to a power grid branch through the load resistor, and the emitter of the IGBT module is grounded through a ninth resistor; The signal indicator light group includes seven groups of signal indication circuits; the first signal indication circuit is used to indicate the working condition of the system control module; the second signal indication circuit is used to indicate the working condition of the zero-crossing detection module, and displays whether the zero-crossing point of the grid voltage is detected normally; the third signal indication circuit is used to indicate the working condition of the drive module, and displays whether the PWM wave is sent normally; the fourth signal indication circuit and the fifth signal indication circuit are used to indicate the working condition of the RS485 chip in the communication module, the fourth signal indication circuit is used for data receiving indication, and the fifth signal indication circuit is used for data sending indication; the sixth signal indication circuit and the seventh signal indication circuit are used to indicate the working condition of the RS232 chip in the communication module, the sixth signal indication circuit is used for data receiving indication, and the seventh signal indication circuit is used for data sending indication; The circuit structures of the signal indication circuits are the same, and they all include an LED and a tenth resistor, wherein the LED adopts a common cathode connection method; in the first signal indication circuit, the LED anode is connected to the I / O port of the system control module, and the LED cathode is grounded through the tenth resistor.

2. The transmitting end of the topology identification system according to claim 1, characterized in that: The communication module includes an RS485 chip and an RS232 chip, which are respectively connected to corresponding communication interfaces of the system control module. The RS485 chip is implemented based on a SIT485BD chip, and the RS232 chip is implemented based on a ST232ECDR chip.

3. The transmitting end of the topology identification system according to claim 1 or 2, characterized in that: The system control module is implemented based on the STM32L431CBT6 chip.

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