Capacitor cabinet motor protection device

Abstract

The invention relates to the technical field of capacitor cabinet motor protection, and discloses a capacitor cabinet motor protection device, which comprises a power supply circuit, a reset circuit, a data acquisition module, a CPU (Central Processing Unit), a signal conditioning and A / D conversion module, a relay output module and a communication module. Wherein the data acquisition module is mainly used for acquiring current and voltage signals of a loop, and the current signal acquisition is output from the secondary side of a field current transformer. Compared with the prior art, the capacitor cabinet motor protection device has the advantages that the capacitor cabinet motor protection device is designed according to the working environment and common faults of the capacitor cabinet motor, the protection device is compact in hardware structure and high in real-time performance, anti-interference design is carried out, the system reliability and stability are enhanced, and therefore when the capacitor cabinet motor works, the capacitor cabinet motor cannot be damaged. And burnout faults are not easy to occur.

Description

Technical Field

[0001] The invention relates to the technical field of capacitor cabinet motor protection, and in particular to a capacitor cabinet motor protection device. Background Art

[0002] The capacitor cabinet motor is a device that provides energy for the switch closing and opening. During the switch operation, the capacitor cabinet motor is storing energy, which can easily cause the motor to burn out. We analyze the causes of capacitor cabinet motor burnout and find that there are three conditions under which the motor is prone to burnout:

[0003] 1. When the motor of the capacitor cabinet starts, the motor does not rotate due to mechanical blocking, but the motor is directly powered on;

[0004] 2. When the motor of the capacitor cabinet starts and stores energy for a period of time, the chain suddenly gets stuck, making the motor unable to continue storing energy, and the motor is directly powered on;

[0005] 3. When the capacitor cabinet motor starts and the energy storage is ready, due to the failure of the travel switch, the power supply circuit of the motor cannot be cut off, and the motor has been idling for a long time.

[0006] At present, domestic motor protection devices generally use single-chip microcomputers as core controllers. Due to the limitations of their own resources and speed, and the fact that very high common-mode voltages are generated during the opening and closing process of the GIS combination switch, electromagnetic interference is very serious. The working environment of the capacitor cabinet motor is harsh and is subject to strong interference. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the above technical difficulties and provide a capacitor cabinet motor protection device to effectively solve the problem that the capacitor cabinet motor is easily burned out.

[0008] In order to solve the above technical problems, the technical solution provided by the present invention is:

[0009] A capacitor cabinet motor protection device, comprising:

[0010] 1. Power circuit

[0011] High speed, low power consumption and low operating voltage result in a very low noise tolerance of the power supply circuit, and very high requirements are placed on the ripple, transient response performance and stability of the clock source of the power supply. The power input terminal of the device is very close to the switch device, and the GIS combination switch will generate large differential mode noise and common mode noise when it is in action. In addition, the AC220V power supply itself also has large interference. A series of anti-interference processing must be performed in the power supply circuit to provide 3.3V, 5V, ±15V, and 24V stable DC power supplies for different modules of the device.

[0012] A resettable fuse LRV100S is connected in series in the circuit for overcurrent and thermal protection. In the power circuit, a surge current is generated when the power is turned on. Thermistor 5D-9 and surge absorber 471KD10 are used to effectively suppress the surge current when the power is turned on. After the surge current is suppressed, the resistance value of the thermistor will drop to a very small level due to the continuous action of the current. The power it consumes can be ignored and will not affect the normal working current. It also provides lightning protection and overvoltage protection. Common-mode choke coil L1 is used to suppress common-mode noise, and safety regulations are used in the circuit. Capacitors Cx1, Cy1 and Cy2, among which the cross-line capacitor Cx1 (X-type capacitor) suppresses differential mode noise; line bypass capacitors Cy1 and Cy2 (Y-type capacitors) suppress common mode noise; use LH10-10D0524AC-DC converter for voltage conversion, which has the characteristics of wide input voltage, DC and AC integration, low output ripple and noise, high efficiency, overload protection and short circuit protection, low power consumption, safe isolation, etc., and outputs 5V and 24V DC; differential mode choke coils L2 and L3 are connected in series at the output DC end to suppress differential mode noise and capacitors (such as Figure 2 As shown in the figure, the differential mode noise is further suppressed; after a series of anti-interference treatments, the output power disturbance is reduced to meet the power supply requirements of the device; the WRA2415LDC-DC converter is used to convert 24V into ±15V DC, and capacitors are used at the output end to suppress differential mode noise. The low voltage drop linear regulator LM1117 is selected to convert 5V into 3.3V DC, and the same is selected at the output end;

[0013] The capacitor suppresses differential mode noise; the interference signal generated by the switching power supply is processed through this series of anti-interference treatment, and the output signal fluctuation is small, which enhances the anti-interference ability of the power supply part and enhances the stability of the system;

[0014] 2. Reset Circuit

[0015] It is a monitoring circuit that can monitor the power supply voltage, the working status of the microprocessor or microcontroller; the button S1 can complete the manual reset, and nTST and CRST are connected to the reset pin of the CPU to complete the automatic reset on power-on; when the program "runs away", by executing the software, the WDI signal is periodically sent to the watchdog to reset the watchdog; the use of this reset circuit provides a strong guarantee for the stability and reliability of the system;

[0016] 3. CPU

[0017] It is a central controller;

[0018] 4. Signal conditioning and A / D conversion module

[0019] The analog signal collected by the data acquisition module needs to be power amplified. The amplifier is powered by a single power supply and has the characteristics of high common-mode rejection, high open-loop gain, and low offset voltage. When an external voltage of ±15V is provided, the output voltage range is 2.7-36V; when the external reference voltage REFV is used, the input analog quantity reaches 0-2REFV, and the ADS chip REFV is set to 2.5V; the output voltage signal enters the ADS7818 chip for A / D conversion, and the ADS7818 uses the SPI bus to communicate with the CPU; only three-way signal isolation is required at the CPU control end, which simplifies the isolation circuit; ADS7818 is a 12-bit high-speed conversion chip with a sampling time of 350nS and a maximum clock frequency of 8MHz;

[0020] The current signal Ismp and voltage signal Vsmp collected by the data acquisition module are input into the A / D control through the analog switch ADG1219, and the analog switch and the CPU are isolated by the photoelectric coupler FODM611; when the device is working, the MUX connection port of the CPU is set to generate a high and low level cycle, so that the two types of collected data are periodically A / D converted; the CPU connection port and the SCLK connection port are the control lines of AD7818, and the SDO connection port is the data line. The ADS7818 chip and the CPU are isolated by FODM611; a coupling capacitor is used at the power supply end of each device for filtering to improve the system's anti-interference ability;

[0021] 5. Relay output module

[0022] The relay output module is the actuator of the capacitor cabinet motor protection device. The DS2E-S-DC24V relay is used as the action mechanism. The relay has high sensitivity and the breakdown voltage can reach 1500V. The relay output module is equipped with a photoelectric isolation circuit. On the one hand, the photoelectric isolation circuit can well isolate the control digital signal sent by the CPU from the analog signal at the output end of the relay circuit, and suppress the noise interference of the analog signal. On the other hand, when the system fails to operate, the protection device outputs a high level to the action response circuit, and drives the intermediate relay through the photoelectric isolation to trip the circuit breaker, thereby cutting off the power supply of the fault circuit.

[0023] 6. Communication module

[0024] Two communication serial port modules are used to realize the communication function between the lower computer and the upper computer; the design of the RS232 communication serial port is mainly to facilitate the debugging and use of internal personnel; RS485 serial port communication is used on site to overcome the shortcomings of RS232 transmission distance and transmission rate, and the RS-485 interface adopts a combination of balanced driver and differential receiver, which has strong anti-common mode interference ability; RS485 uses 5V isolator-type transceiver ISO3082 to work in half-duplex mode for data transmission and reception; Compared with traditional high-speed optocouplers, digital isolators have the advantages of low power consumption, high transmission rate, compatibility with 3V / 5V systems and simple peripherals; B0505DC-DC chip is used to provide a second power supply for the transceiver to achieve power isolation, suppress power supply noise interference, and ensure the stability and reliability of RS485.

[0025] The advantages of the present invention compared with the prior art are:

[0026] Aiming at the working environment and common faults of the capacitor cabinet motor, the present invention designs a capacitor cabinet motor protection device, so that the hardware structure of the protection device is compact and the real-time performance is high, and an anti-interference design is performed, and the system reliability and stability are enhanced, so that the capacitor cabinet motor is not prone to burnout faults when working. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the present invention.

[0028] Figure 2 It is a work flow chart of the present invention. DETAILED DESCRIPTION

[0029] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more. In addition, the term "includes" and any variation thereof are intended to cover non-exclusive inclusions.

[0030] The present invention is further described in detail below in conjunction with the implementation modes and the accompanying drawings.

[0031] A capacitor cabinet motor protection device includes a power supply circuit (also called: DC / DC power supply module), a reset circuit (also called: emergency bypass), a data acquisition module (also called: coil protection detection part), a CPU (central controller), a signal conditioning and A / D conversion module (also called: coil protection control part), a relay output module (also called: signal output) and a communication module (specifically a signal light and remote signal). Among them, the data acquisition module mainly collects the current and voltage signals of the loop, and the current signal is collected from the secondary side output of the on-site current transformer.

[0032] Power supply circuit: High speed, low power consumption and low operating voltage result in a very low noise tolerance of the power supply circuit, and very high requirements are placed on the ripple, transient response performance and stability of the clock source of the power supply; the power input terminal of the device is very close to the switch device, and the GIS combination switch will generate large differential mode noise and common mode noise when it is in action. In addition, the AC220V power supply itself also has large interference. A series of anti-interference processing must be performed in the power supply circuit to provide 3.3V, 5V, ±15V, and 24V stable DC power supplies for different modules of the device;

[0033] A resettable fuse LRV100S is connected in series in the circuit for overcurrent and thermal protection. In the power circuit, a surge current is generated when the power is turned on. Thermistor 5D-9 and surge absorber 471KD10 are used to effectively suppress the surge current when the power is turned on. After the surge current is suppressed, the resistance value of the thermistor will drop to a very small level due to the continuous action of the current. The power it consumes can be ignored and will not affect the normal working current. It also provides lightning protection and overvoltage protection. Common-mode choke coil L1 is used to suppress common-mode noise, and safety regulations are used in the circuit. Capacitors Cx1, Cy1 and Cy2, among which the cross-line capacitor Cx1 (X-type capacitor) suppresses differential mode noise; line bypass capacitors Cy1 and Cy2 (Y-type capacitors) suppress common mode noise; use LH10-10D0524AC-DC converter for voltage conversion, which has the characteristics of wide input voltage, DC and AC integration, low output ripple and noise, high efficiency, overload protection and short circuit protection, low power consumption, safe isolation, etc., and outputs 5V and 24V DC; differential mode choke coils L2 and L3 are connected in series at the output DC end to suppress differential mode noise and capacitors (such as Figure 2 As shown in the figure, the differential mode noise is further suppressed; after a series of anti-interference treatments, the output power disturbance is reduced to meet the power supply requirements of the device; the WRA2415LDC-DC converter is used to convert 24V into ±15V DC, and capacitors are used at the output end to suppress differential mode noise. The low voltage drop linear regulator LM1117 is selected to convert 5V into 3.3V DC, and the same is selected at the output end;

[0034] The capacitor suppresses differential mode noise; the interference signal generated by the switching power supply is processed through this series of anti-interference treatment, and the output signal fluctuation is small, which enhances the anti-interference ability of the power supply part and enhances the stability of the system;

[0035] Reset circuit: It is a monitoring circuit that can monitor the power supply voltage and the working status of the microprocessor or microcontroller. The button S1 can be used to complete manual reset. The connection of nTST and CRST to the reset pin of the CPU can complete automatic reset on power-on. When the program "runs away", the software is executed to periodically send a WDI signal to the watchdog to reset the watchdog. The use of this reset circuit provides a strong guarantee for the stability and reliability of the system.

[0036] Signal conditioning and A / D conversion module: The analog signal collected by the data acquisition module needs to be power amplified. The amplifier is powered by a single power supply and has the characteristics of high common-mode rejection, high open-loop gain, and low offset voltage. When an external voltage of ±15V is provided, the output voltage range is 2.7-36V; when the external reference voltage REFV is used, the input analog quantity reaches 0-2REFV, and the ADS chip REFV is set to 2.5V; the output voltage signal enters the ADS7818 chip for A / D conversion, and the ADS7818 uses the SPI bus to communicate with the CPU; only three-way signal isolation is required at the CPU control end, which simplifies the isolation circuit; ADS7818 is a 12-bit high-speed conversion chip with a sampling time of 350nS and a maximum clock frequency of 8MHz;

[0037] The current signal Ismp and voltage signal Vsmp collected by the data acquisition module are input into the A / D control through the analog switch ADG1219, and the analog switch and the CPU are isolated by the photoelectric coupler FODM611; when the device is working, the MUX connection port of the CPU is set to generate a high and low level cycle, so that the two types of collected data are periodically A / D converted; the CPU connection port and the SCLK connection port are the control lines of AD7818, and the SDO connection port is the data line. The ADS7818 chip and the CPU are isolated by FODM611; a coupling capacitor is used at the power supply end of each device for filtering to improve the system's anti-interference ability;

[0038] Relay output module: The relay output module is the actuator of the capacitor cabinet motor protection device. It uses the DS2E-S-DC24V relay as the action mechanism. The relay has high sensitivity and a breakdown voltage of up to 1500V. The relay output module is equipped with a photoelectric isolation circuit. On the one hand, the photoelectric isolation circuit can well isolate the control digital signal sent by the CPU from the analog signal at the output end of the relay circuit, thereby suppressing the noise interference of the analog signal. On the other hand, when a system operation failure occurs, the protection device outputs a high level to the action response circuit, which drives the intermediate relay through photoelectric isolation to trip the circuit breaker, thereby cutting off the power supply of the fault circuit.

[0039] Communication module: Two communication serial port modules are used to realize the communication function between the lower computer and the upper computer; the design of the RS232 communication serial port is mainly to facilitate the debugging and use of internal personnel; RS485 serial port communication is used on site to overcome the shortcomings of RS232 transmission distance and transmission rate, and the RS-485 interface adopts a combination of balanced driver and differential receiver, which has strong anti-common mode interference ability; RS485 uses 5V isolator-type transceiver ISO3082 to work in half-duplex mode for data transmission and reception; Compared with traditional high-speed optocouplers, digital isolators have the advantages of low power consumption, high transmission rate, compatibility with 3V / 5V systems and simple peripherals; B0505DC-DC chip is used to provide a second power supply for the transceiver to achieve power isolation, suppress power supply noise interference, and ensure the stability and reliability of RS485.

[0040] The present invention and its embodiments are described above, and such description is not restrictive. If a person skilled in the art is inspired by it and designs an embodiment similar to the technical solution without creativity without departing from the purpose of the invention, it shall fall within the protection scope of the present invention.

Claims

1. A capacitor cabinet motor protection device, characterized in that: include:

1. Power circuit High speed, low power consumption and low operating voltage result in a very low noise tolerance of the power supply circuit, and very high requirements are placed on the ripple, transient response performance and stability of the clock source of the power supply. The power input terminal of the device is very close to the switch device, and the GIS combination switch will generate large differential mode noise and common mode noise when it is in action. In addition, the AC220V power supply itself also has large interference. A series of anti-interference processing must be performed in the power supply circuit to provide 3.3V, 5V, ±15V, and 24V stable DC power supplies for different modules of the device. A self-recovery fuse LRV100S is connected in series in the circuit for overcurrent and thermal protection. In the power circuit, a surge current will be generated at the moment of power on. Thermistor 5D-9 and surge absorber 471KD10 are used to effectively suppress the surge current at power on. After the surge current suppression is completed, due to the continuous action of the current, the resistance value of the thermistor will drop to a very small level. The power it consumes can be ignored and will not affect the normal working current. It also provides lightning protection and overvoltage protection. Common-mode choke coil L1 is used to suppress common-mode noise. Safety capacitors Cx1, Cy1 and Cy2 are used in the loop. The cross-line capacitor Cx1 (X-type capacitor) suppresses differential-mode noise; line bypass capacitors Cy1 and Cy2 (Y-type capacitors) suppress common-mode noise ; Use LH10-10D0524AC-DC converter for voltage conversion. The converter has the characteristics of wide input voltage, DC and AC integration, low output ripple and noise, high efficiency, overload protection and short circuit protection, low power consumption, safety isolation, etc., and outputs 5V and 24V DC power; differential mode choke coils L2 and L3 are connected in series at the output DC end to suppress differential mode noise and capacitors are used to further suppress differential mode noise; after a series of anti-interference treatments, the output power disturbance is small to meet the power supply requirements of the device; use WRA2415LDC-DC converter to convert 24V into ±15V DC power, use capacitors at the output end to suppress differential mode noise, and use low voltage drop linear regulator LM1117 to convert 5V into 3.3V DC power, which is also selected at the output end; The capacitor suppresses differential mode noise; the interference signal generated by the switching power supply is processed through this series of anti-interference treatment, and the output signal fluctuation is small, which enhances the anti-interference ability of the power supply part and enhances the stability of the system; 2. Reset Circuit It is a monitoring circuit that can monitor the power supply voltage, the working status of the microprocessor or microcontroller; the button S1 can complete the manual reset, and nTST and CRST are connected to the reset pin of the CPU to complete the automatic reset on power-on; when the program "runs away", by executing the software, the WDI signal is periodically sent to the watchdog to reset the watchdog; the use of this reset circuit provides a strong guarantee for the stability and reliability of the system; 3. CPU It is a central controller; 4. Signal conditioning and A / D conversion module The analog signal collected by the data acquisition module needs to be power amplified. The amplifier is powered by a single power supply and has the characteristics of high common-mode rejection, high open-loop gain, and low offset voltage. When an external voltage of ±15V is provided, the output voltage range is 2.7-36V; when the external reference voltage REFV is used, the input analog quantity reaches 0-2REFV, and the ADS chip REFV is set to 2.5V; the output voltage signal enters the ADS7818 chip for A / D conversion, and the ADS7818 uses the SPI bus to communicate with the CPU; only three-way signal isolation is required at the CPU control end, which simplifies the isolation circuit; ADS7818 is a 12-bit high-speed conversion chip with a sampling time of 350nS and a maximum clock frequency of 8MHz; The current signal Ismp and voltage signal Vsmp collected by the data acquisition module are input into the A / D control through the analog switch ADG1219, and the analog switch and the CPU are isolated by the photoelectric coupler FODM611; when the device is working, the MUX connection port of the CPU is set to generate a high and low level cycle, so that the two types of collected data are periodically A / D converted; the CPU connection port and the SCLK connection port are the control lines of AD7818, and the SDO connection port is the data line. The ADS7818 chip and the CPU are isolated by FODM611; a coupling capacitor is used at the power supply end of each device for filtering to improve the system's anti-interference ability; 5. Relay output module The relay output module is the actuator of the capacitor cabinet motor protection device. The DS2E-S-DC24V relay is used as the action mechanism. The relay has high sensitivity and the breakdown voltage can reach 1500V. The relay output module is equipped with a photoelectric isolation circuit. On the one hand, the photoelectric isolation circuit can well isolate the control digital signal sent by the CPU from the analog signal at the output end of the relay circuit, and suppress the noise interference of the analog signal. On the other hand, when the system fails to operate, the protection device outputs a high level to the action response circuit, and drives the intermediate relay through the photoelectric isolation to trip the circuit breaker, thereby cutting off the power supply of the fault circuit.

6. Communication module Two communication serial port modules are used to realize the communication function between the lower computer and the upper computer; the design of the RS232 communication serial port is mainly to facilitate the debugging and use of internal personnel; RS485 serial port communication is used on site to overcome the shortcomings of RS232 transmission distance and transmission rate, and the RS-485 interface adopts a combination of balanced driver and differential receiver, which has strong anti-common mode interference ability; RS485 uses 5V isolator-type transceiver ISO3082 to work in half-duplex mode for data transmission and reception; Compared with traditional high-speed optocouplers, digital isolators have the advantages of low power consumption, high transmission rate, compatibility with 3V / 5V systems and simple peripherals; B0505DC-DC chip is used to provide a second power supply for the transceiver to achieve power isolation, suppress power supply noise interference, and ensure the stability and reliability of RS485.

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