CN210137213U

CN210137213U - Distribution automation feeder terminal line loss collection equipment

Info

Publication number: CN210137213U
Application number: CN201921493299.3U
Authority: CN
Inventors: 张钢; 王磊; 刘波
Original assignee: Qingdao Leader New Energy Co Ltd
Current assignee: Qingdao Leader New Energy Co Ltd
Priority date: 2019-09-10
Filing date: 2019-09-10
Publication date: 2020-03-10
Anticipated expiration: 2029-09-10

Abstract

The utility model belongs to the power transmission field provides a distribution automation feeder terminal line loss collection equipment, including power supply module, microprocessor control module, storage module, communication module and metering module, power module is used for exporting direct current voltage for microprocessor control module, communication module and metering module power supply, and microprocessor control module's input is connected with metering module, and the output passes through communication module and is connected with the host computer, and input/output end is connected with storage module; the microprocessor control module comprises an MCU main chip HT 6025. The utility model has the advantages of small in size, precision height, good reliability, simple to operate, scene can dispose line system parameter according to practical application, can wide application in the electric power distribution field.

Description

Distribution automation feeder terminal line loss collection equipment

Technical Field

The utility model belongs to the electric power field, concretely relates to distribution automation feeder terminal line loss collection equipment.

Background

The Feeder Terminal (FTU) is a distribution automation terminal which is arranged on a post of a distribution network feeder loop, a switch cabinet and the like and has remote signaling, remote measuring, remote controlling and feeder automation functions. With the huge investment in the aspect of electric power infrastructure in China, the construction of a power distribution network correspondingly makes great progress, the scale of the power distribution network is continuously enlarged, the difficulty of operation management is increased, and the requirement on the reliability of power supply of the power distribution network is improved, so that the automation level of the power distribution network is required to be improved, and the structure of the power distribution network is perfected and optimized. Especially, the establishment of the principle of 'simplification and intellectualization' of the construction of the power distribution network, and the perfection of the construction of the network frame terminal of the distribution network becomes the key point of the construction of the distribution network in China at present. The power distribution network is a key component of a power system and plays an important role in normal production and life of the society. Distribution network line loss mainly refers to the phenomenon of electric energy loss caused by various internal and external factors in the long-term operation process of a power grid.

And (5) management in the aspects of stable and economic operation of the power distribution network without line disconnection loss. In a power distribution network, line loss is a factor directly causing power loss, and the factor cannot be eliminated, and only effective measures can be taken to reduce the line loss. The line loss management work of the power distribution network is always the work key of power supply enterprises, scientific solution is made, power supply equipment is reasonably optimized, and the line loss problem is favorably solved, so that the stability and the economical efficiency of power transmission of the power distribution network can be improved, and the low-consumption operation of resources is realized.

The line loss measurement of the existing distribution feeder terminal is the integrated design of the feeder terminal and a line loss measurement module, the measurement precision of the distribution terminal cannot be checked in the mode, and if the situation that line system wiring is not matched with the actual situation (three-phase four-line system equipment is used for three-phase three-line system wiring) occurs on site, the original distribution terminal cannot realize the on-site adjustment wiring mode, the whole equipment needs to be replaced to meet the on-site installation requirement, and great trouble is brought to on-site installation and debugging.

SUMMERY OF THE UTILITY MODEL

For the actual demand that adapts to the electric power field, the utility model overcomes the not enough of prior art existence, the technical problem that solve is for providing a distribution automation feeder terminal line loss collection equipment to realize the independent collection of line loss and the check-up at power equipment distribution automation feeder terminal.

In order to solve the technical problem, the utility model discloses a technical scheme be: a distribution automation feeder terminal line loss acquisition device comprises a power supply module, a microprocessor control module, a storage module, a communication module and a metering module, wherein the power supply module is used for outputting direct-current voltage to supply power to the microprocessor control module, the communication module and the metering module; the microprocessor control module comprises an MCU main chip HT6025, a pin LVDIN of the MCU main chip HT6025 is connected with the anode of the 5V direct-current power supply through a resistor R6, and is grounded through a resistor R7 and a capacitor C1 respectively; a pin TEST of the MCU main chip HT6025 is connected with the anode of the 3V direct-current power supply through a pull-up resistor R8 and is grounded through a capacitor C3; pin RESET of the MCU main chip HT6025 is grounded via a capacitor C1, pin SGND is grounded, pin VSYS is connected to the positive electrode of the 3.3V dc power supply, and is also grounded via a capacitor C7.

The microprocessor control module further comprises a crystal oscillator Y2, and two ends of the crystal oscillator Y2 are respectively connected with a pin OSCI and a pin OSCO of the MCU main chip HT 6025; the capacitance values of the capacitor C4 and the capacitor C3 are 0.1uF and 0.01uF respectively, the resistance value of the pull-up resistor R8 is 1K omega, and the resistance values of the resistor R6 and the resistor R7 are 100K omega and 63K omega respectively.

The power supply module comprises a first power supply conversion circuit, a second power supply conversion circuit and a third power supply conversion circuit, wherein the first power supply conversion circuit comprises a voltage dependent resistor YG, a capacitor C101, a diode D4, a power supply module U1 and a capacitor C2, the voltage dependent resistor YG and the capacitor C101 are connected between the positive pole of an input 48V direct-current voltage and the ground in parallel, the positive pole of the input 48V direct-current voltage is connected with a pin Vin of the power supply module U1 after passing through a diode D4, a pin Vout of the power supply module U1 serves as a 5V power supply output end of the first power supply circuit to output 5V direct-current voltage to supply power to the second power supply conversion circuit and the third power supply conversion circuit, and the capacitor C102 is connected between the pin Vout of the power supply module U1 and;

the second power conversion circuit comprises a power module U4, a capacitor C53, a diode D1, a diode D2 and a battery BAT, a pin VIN of the power module U4 is connected with a 5V power output end of the first power circuit, and a pin VOUT outputs 3.3V direct-current voltage to supply power for the MCU main chip HT6025 and the metering module; a pin VOUT of the power module U4 outputs 3.3V direct current voltage, 3V VRTC voltage is generated after the direct current voltage passes through a diode D1 to supply power to a pin VRTC of the MCU master chip HT6025, and 2.8V VRTC voltage is generated after the battery BAT passes through a diode D2 to supply power to a pin VRTC of the MCU master chip HT 6025;

the third power conversion circuit comprises a capacitor C103, a power module U2 and a capacitor C104, a pin Vin of the power module U2 is connected with a 5V power output end of the first power circuit, a pin Vo outputs a direct-current voltage V485 to supply power to the communication module, the capacitor C103 is connected between the pin Vin of the power module U2 and the ground, and the capacitor C104 is connected between the pin Vo of the power module U2 and the ground.

The model of the power supply module U1 is ZY4805WHBD-3W1, the model of the power supply module U2 is ZY0505IFS-1W, the model of the power supply module U4 is S1206B33, and the output power supply of the battery BAT is 3.6V.

The metering module comprises a metering chip, a voltage sampling circuit and a current sampling circuit, wherein the output end of the voltage sampling circuit and the output end of the current sampling circuit are connected with the input end of the metering chip.

The voltage sampling circuit comprises three current type voltage transformers and three voltage sampling filter circuits, wherein each phase voltage is respectively connected with the input end of each current type voltage transformer after passing through a high-precision non-inductive resistor, the output end of each current type voltage transformer is respectively connected with one channel of the metering chip ATT7022E after passing through one sampling filter circuit, each voltage sampling filter circuit comprises a resistor R38, a resistor R42, a capacitor 19 and a capacitor C22, after the resistor R38 is connected with the capacitor C19 in parallel, one end of each voltage sampling filter circuit is connected with the output end of each current type voltage transformer and one voltage channel pin VP of the metering chip, and the other end of each voltage sampling filter circuit is connected with the ground; after the resistor R42 is connected with the capacitor C22 in parallel, one end of the resistor R42 is connected with the ground, and the other end of the resistor R42 is connected with a pin VN of the same voltage channel of the metering chip;

the current sampling circuit comprises three current transformers and three current sampling filter circuits, each phase of current is connected with the input end of one current transformer, the output ends of the current transformers are connected with one channel of the metering chip ATT7022E after passing through one current sampling filter circuit respectively, the current sampling filter circuit comprises a resistor R28, a resistor R31, a resistor R34, a resistor R37, a capacitor C13 and a capacitor C16, one ends of the resistor R31 and the resistor R28 are connected with the output end of the current transformers, the other end of the resistor R31 is connected with the ground, the other end of the resistor R28 is connected with a pin VP of one current channel of the metering chip, and the capacitor C13 is connected between the other end of the resistor R28 and the ground; one end of the resistor R34 is connected with one end of the resistor R37, the other end of the resistor R34 is connected with the ground, the other end of the resistor R37 is connected with a pin VN of the same current channel of the metering chip, and the capacitor C16 is connected between the other end of the resistor R27 and the ground;

the type of the metering chip is ATT7022E, a pin AVCC of the metering chip is connected with a power supply through a resistor R43 and is grounded through a capacitor C89 and a capacitor C96 which are connected in parallel, a pin REFCAP is grounded through capacitors C17 and C20 which are connected in parallel, a pin VCC is grounded through a capacitor C77, a pin VDD is grounded through a capacitor C23 and a capacitor C25 which are connected in parallel, and a pin DOUNT, a pin DIN, a pin SLCK and a pin CS are connected with the MCU main chip HT 6025.

The communication module comprises an RS485 communication circuit and an RS232 communication circuit; the RS485 communication circuit and the RS232 communication circuit are connected with the microprocessor control module through a jumper terminal UART; the RS485 communication circuit comprises an isolation circuit and an RS485 communication chip U15, and the RS485 communication chip U15 is connected with a jumper terminal UART through the isolation circuit; the RS232 communication circuit comprises an RS232 communication chip U16 and peripheral circuits.

The model of the RS485 communication chip U15 is BL 3085A; the RS232 communication circuit comprises an RS232 communication chip U16, and the model of the RS232 communication chip U16 is MAX 232.

The storage module comprises an EEPROM memory, and the EEPROM memory is connected with the MCU main chip HT6025 through the IIC.

The microprocessor control module also comprises a program downloading and debugging interface ISP, and the program downloading and debugging interface ISP is connected with a pin TMS, a pin TCK and a pin TEST of the MCU main chip HT6025 and is also connected with a 3.3V direct-current voltage anode and a GND ground.

Compared with the prior art, the utility model following beneficial effect has: the device has the advantages of small volume, high precision, good reliability, convenient installation, capability of configuring wire system parameters according to practical application on site and the like. The device can provide various external error verification interfaces, data acquisition interfaces and communication interfaces, can realize the error precision of the line loss module to be detected in advance and the error precision of the line loss module to be detected in the using process, greatly ensures the source tracing basis of the field application power distribution terminal on the line loss metering error precision, and provides important data support for tracing and judging the line loss metering accuracy of the power enterprises.

Drawings

Fig. 1 is a schematic block diagram of a power distribution automation feeder terminal line loss acquisition device according to an embodiment of the present invention;

FIG. 2 is a circuit schematic of a microprocessor control module and a memory module;

FIG. 3 is a schematic circuit diagram of a power conversion circuit;

FIG. 4 is a circuit schematic of a metering module;

fig. 5 is a circuit schematic of a communication module.

Detailed Description

In order to make the technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments and accompanying drawings, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention; based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

As shown in fig. 1, this embodiment provides a distribution automation feeder terminal line loss collection equipment, including power module, microprocessor control module, storage module, communication module and metering module, power module is used for exporting direct current voltage and gives microprocessor control module, communication module and metering module power supply, microprocessor control module's input is connected with metering module, and the output passes through communication module and is connected with the host computer, input/output end with storage module connects.

As shown in fig. 2, the microprocessor control module includes an MCU main chip HT6025, a pin LVDIN of the MCU main chip HT6025 is connected to a positive electrode of the 5V dc power supply through a resistor R6, and is further grounded through a resistor R7 and a capacitor C1, respectively; a pin TEST of the MCU main chip HT6025 is connected with the anode of the 3V direct-current power supply through a pull-up resistor R8 and is grounded through a capacitor C3; pin RESET of the MCU main chip HT6025 is grounded via a capacitor C1, pin SGND is grounded, pin VSYS is connected to the positive electrode of the 3.3V dc power supply, and is also grounded via a capacitor C7.

As shown in fig. 2, the microprocessor control module further includes a crystal oscillator Y2, and two ends of the crystal oscillator Y2 are respectively connected to the pin OSCI and the pin OSCO of the MCU main chip HT 6025; the capacitance values of the capacitor C4 and the capacitor C3 are 0.1uF and 0.01uF respectively, the resistance value of the pull-up resistor R8 is 1K omega, and the resistance values of the resistor R6 and the resistor R7 are 100K omega and 63K omega respectively.

In this embodiment, the MCU main chip adopts an 80 pin HT6025 high performance processor of the shanghai moment spring photoelectric company, which has the characteristics of multifunction, high performance, and low power consumption, and integrates a Cortex-M0 processor, 256K, FLASH, 32K SRAM, units such as clock management, power management, hardware auto temperature compensation RTC, PLL, high frequency RC, low frequency RC, LCD driver, and NVIC and DEBUG functions. The working voltage range is 2.0V to 5.5V, and the maximum working flat rate is 44 MHz. The RTC unit supports a compensation mechanism per second, a chip takes a 32.768KHz crystal oscillator clock source as an RTC clock source, and the automatic digital compensation unit of the clock integrated in the chip assists a user to realize the automatic compensation of the RTC without software participation of the user. The CPU maximum working frequency reaches 44M, a high-precision temperature sensor is arranged in the CPU: the temperature sensor consistency is better than plus or minus 1 degree in the temperature range of minus 40 to plus 85 degrees.

In addition, a passive crystal Y2 and a 32.76kHz crystal oscillator are arranged outside the MCU main chip, and a working clock source and an accurate clock source are provided for the system and the RTC. The LVDIN pin (3 pin) of the MCU is a low voltage detection pin, the system is converted into 5V and then is reduced to 3.3V after 48V is converted into 5V, in order to detect the change of the voltage in advance, the change of the 5V voltage is detected, the 3.3V system is divided into R6(100K) and R7(62K) through resistors, the divided voltage is 1.9V, C1 is a filter capacitor, the jitter and the interference are prevented, and a low voltage detection mark is generated when the LVDIN voltage of an external pin is reduced to be lower than 1.21V. Therefore, the relevant function of the power-off processing can be made in advance, and the effective storage of data is ensured. The 4 pins of the MCU are test pins, the low level is effective, the design at the place is a program downloading and debugging interface, and the high level R8(1K) C3(0.01uF) at the initial state is fixed by a pull-up resistor and a filter capacitor from the outside. If a data downloading or debugging task exists, the upper computer at the position can forcibly pull down the level at the position. The 5 pin of the MCU is a reset pin, and because the chip is internally provided with a pull-up resistor, the MCU is externally connected with only a capacitor C4(0.1uF) capable of delaying 2 uS. Pins 53 and 52 of the system power supply MCU are respectively 3.3V and GND, and a filter capacitor C7 is added.

In addition, the storage module of the embodiment is an EEPROM memory, and the EEPROM memory is connected with the MCU main chip HT6025 through the IIC. 1 EEPROM of the MCU plug-in IIC communication device is used for storing metering related parameters, and the internal storage comprises meter calibration data, event recording data, electric energy storage data and the like which are respectively 55-56 pins of the MCU; because the pin is open-drain output, pull-up resistors R1 and R2 are added, EEPROM addresses A0-A2 are all address 0, and the WP pin is directly grounded to default to a write-enabled state.

In addition, MCU main chip passes through SPI data interface connection with the measurement chip, and MCU's 20 ~ 23 pins correspond 4 signals of MISOI data output, MOSI data input, CLK clock, CS chip selection of SPI communication respectively.

In addition, the microprocessor control module of this embodiment further includes a program download and debug interface ISP, where the program download and debug interface ISP is connected to the pin TMS, the pin TCK, and the pin TEST of the MCU main chip HT6025, and further connected to the 3.3V dc positive electrode and the GND ground. The program downloading and debugging interface ISP is used for providing a system power supply and a ground for the outside and simultaneously providing TMS, TCK and TEST signals, wherein TMS is a data input and output interface, TCK is a data clock interface, and TEST is a debugging signal interface. And the MCU main chip carries out data interaction outside through the 5 lines.

As shown in fig. 1, the power module includes a first power conversion circuit, a second power conversion circuit, and a third power conversion circuit, where the first power conversion circuit converts an input 48V dc voltage into a 5V dc voltage and outputs the 5V dc voltage to the second power conversion circuit and the third power conversion circuit. The second power conversion circuit converts the 5V direct current voltage into 3.3V and outputs the 3.3V direct current voltage to the MUC main chip and the metering module for power supply, and the second power conversion circuit converts the 5V direct current voltage into 3.3V direct current voltage and outputs the 3.3V direct current voltage to the communication module for power supply.

As shown in fig. 3, the first power conversion circuit includes a voltage dependent resistor YG, a capacitor C101, a diode D4, a power module U1, and a capacitor C2, the voltage dependent resistor YG and the capacitor C101 are connected in parallel between the positive terminal of the input 48V dc voltage and ground, the positive terminal of the input 48V dc voltage is connected to the pin Vin of the power module U1 via the diode D4, the pin Vout of the power module U1 is used as the 5V power output terminal of the first power circuit to output 5V dc voltage to power the second power conversion circuit and the third power conversion circuit, and the capacitor C102 is connected between the pin Vout of the power module U1 and ground. Specifically, in the present embodiment, the system allows an input voltage range of 16VDC to 72VDC, with the primary consideration being to support universal 24VDC and 48VDC power supply compatibility. The design selects power module U1, ZY4805WHBD-3W produced by Zhou Li Gong science and technology, the ripple coefficient of the output direct current voltage stabilization 5V power supply of the module is less than 5%, the maximum output power is 3W, and the maximum power consumption of the product design is 3W. The YG14D101K voltage dependent resistor in the circuit has the function of clamping the input voltage too high, the clamping voltage value is 85V, the action time is less than 20uS, and the burning of the internal devices and the circuit after the instantaneous high voltage input is avoided. The electrolytic capacitor C101(100V/47uF) mainly plays a role in filtering and energy storage, high-frequency noise carried in an input power supply is filtered, the stability of the input power supply is ensured, the diode D4(M7) mainly plays a role in preventing the input power supply from being reversely connected and then burning a power supply module, and because the power supply module has an output voltage stabilizing function, the electrolytic capacitor C2(16V/470uF) is only provided for filtering on the output side, and the design of the capacitor cannot exceed the maximum capacitive load of the output.

As shown in fig. 3, the second power conversion circuit includes a power module U4, a capacitor C53, a diode D1, a diode D2, and a battery BAT, a pin VIN of the power module U4 is connected to a 5V power output terminal of the first power circuit, and a pin VOUT outputs 3.3V dc voltage to power the MCU main chip HT6025 and the metering module; the pin VOUT of the power module U4 outputs 3.3V direct current voltage, 3V VRTC voltage is generated after the direct current voltage passes through the diode D1 to supply power to the pin VRTC of the MCU main chip HT6025, and the battery BAT generates 2.8V VRTC voltage after the direct current voltage passes through the diode D2 to supply power to the pin VRTC of the MCU main chip HT 6025. The space limit is considered, so the power supply of the MCU main chip and the working power supply of the metering loop are output by the same path, and the working power supplies of the MCU main chip and the metering chip are 3.3V, so 5V of the system needs to be reduced to 3.3V through the power conversion chip for the system to work and use. The design U4 provides the power supply for system MCU and metering circuit, and the model is the S-B1206B33 low dropout high precision power supply chip of the fine work, and 1V between the input and the output of the chip can not only stabilize the output, but also provide the maximum 150mA current capability, and the linearity meets the linear requirement of 1%. In addition, the MCU and the metering power supply input power supply V3.3/VD7022 generate VRTC power supply 3V through D1(LL4148), and the backup battery generates VRTC power supply 2.8V after passing through a diode D2 (M7). Therefore, when the system voltage is normal, the high-voltage priority output principle is adopted, the system clock power supply is converted from V3.3 through a diode D1, the power supply voltage is 3V, and after the system power supply is powered off and the power supply drops below 2.8V, the real-time clock power supply is provided by the standby battery, so that the system clock power supply still works after the system is powered off.

As shown in fig. 3, the third power conversion circuit includes a capacitor C103, a power module U2, and a capacitor C104, a pin Vin of the power module U2 is connected to the 5V power output terminal of the first power circuit, a pin Vo outputs a dc voltage V485 to supply power to the communication module, the capacitor C103 is connected between the pin Vin of the power module U2 and ground, and the capacitor C104 is connected between the pin Vo of the power module U2 and ground. In the embodiment, an external communication interface is provided, and the communication interface needs to be isolated from an internal circuit, so that an isolated power supply module U2 with the model of ZY0505IFS-1W is additionally selected to provide a working 5V direct-current power supply for an RS485 circuit and an RS232 circuit. Considering that only one of the final RS485 and RS232 circuits in this embodiment can be selected, the isolation module with output power of 1W is selected. The isolation power supply is 5V to 5V, the input voltage is provided by V5V through a main power supply U1, and the output power supply is used for supplying a communication interface. The capacitor C103 and the capacitor C104 mainly function to filter input and output voltage signals, so that the input and output signals are smoother, and interference of a power supply to a system is reduced.

In this embodiment, the metering module includes a metering chip, a voltage sampling circuit and a current sampling circuit, and an output terminal of the voltage sampling circuit and an output terminal of the current sampling circuit are connected to an input terminal of the metering chip.

Specifically, as shown in fig. 4, the voltage sampling circuit includes three current-type voltage transformers and three voltage sampling filter circuits, each phase voltage is connected to an input terminal of the current-type voltage transformer after passing through a high-precision non-inductive resistor, an output terminal of the current-type voltage transformer is connected to one channel of the metering chip ATT7022E after passing through a sampling filter circuit, the voltage sampling filter circuit includes a resistor R38, a resistor R42, a capacitor 19 and a capacitor C22, after the resistor R38 is connected to the capacitor C19 in parallel, one end of the resistor R38 is connected to the output terminal of the current-type voltage transformer and one voltage channel pin VP of the metering chip, and the other end of the resistor R38 is connected to ground; after the resistor R42 is connected in parallel with the capacitor C22, one end of the resistor R42 is connected with the ground, and the other end of the resistor R42 is connected with a pin VN of the same voltage channel of the metering chip.

Specifically, as shown in fig. 4, the current sampling circuit includes three current transformers and three current sampling filter circuits, each phase of current is connected to an input terminal of one current transformer, output terminals of the current transformers are connected to one channel of the metering chip ATT7022E after passing through one current sampling filter circuit, the current sampling filter circuit includes a resistor R28, a resistor R31, a resistor R34, a resistor R37, a capacitor C13, and a capacitor C16, one ends of the resistor R31 and the resistor R28 are connected to an output terminal of the current transformer, the other end of the resistor R31 is connected to ground, the other end of the resistor R28 is connected to a pin VP of one current channel of the metering chip, and the capacitor C13 is connected between the other end of the resistor R28 and ground; one end of the resistor R34 is connected with one end of the resistor R37, the other end of the resistor R34 is connected with the ground, the other end of the resistor R37 is connected with a pin VN of the same current channel of the metering chip, and the capacitor C16 is connected between the other end of the resistor R27 and the ground.

Specifically, the voltage sampling passes through the secondary side of a current type voltage transformer (PT1-PT3/HPT225HN, the input and output are 2mA:2mA, and the maximum current is 10mA), then the current signal is converted into a voltage signal, and the voltage signal is input to the metering chip. The 3-path single-phase voltage input is the same design, taking a PT1 circuit as an example, UA (A-phase voltage 220V) generates about 18mA current signals through 1 high-precision non-inductive resistor RA (1.2M/1%/20 ppm/1W) and then transmits the signals to a channel A sampling channel of a metering chip through a T1 mutual inductor at equal ratio, the high-precision non-inductive resistor is adopted mainly because the mutual inductor has certain cross-over, if the cross-over of input signals is influenced by the resistor, the cross-over becomes large, and the accuracy of error precision is accurate, and the non-inductive resistor is specially adopted. The current signal generates an input voltage after passing through a resistor R38 in the channel A, then passes through a C19 filter, and is input into sampling pins VP2 and VN2 of a metering chip, and the VN2 is designed into a symmetrical circuit which is the same as that of VP2, so that the balance of sampling data is ensured. The design is mainly that the cross ratio of the current transformer is smaller than 10 degrees, the resistors are high-precision noninductive low-temperature drift resistors and R38 high-precision low-temperature drift resistors, so that the product meeting the 0.5S-level sampling precision is guaranteed to be designed, and meanwhile, the transformer has the effect of isolating strong electricity and weak points. The current signals are respectively collected A, B, C three-phase currents through a current transformer (HCT226HJZ-25A/2.5mA 0.05 grade) CT1, a CT2 and a CT3, then the three-phase currents are converted into voltage signals through resistors (R31, R34 and the like), and the voltage signals are input through an RC low-pass filter, namely a resistor R28 and a capacitor C13. The RC low-pass filter is selected as an important guarantee part of the precision of the metering loop, and in the RC low-pass filter of this embodiment, R28 is 1k, C13 is 0.033uF, and the cutoff frequency is about 4.8 kHz. In order to meet the design of 0.5S-level accuracy index of the system, R31 and R34 have to select resistors with accuracy higher than 1% and small temperature coefficient change range.

Specifically, as shown in fig. 4, the metering chip adopts an ATT7022E multifunctional high-precision three-phase electric energy special metering chip of spring opto-electronic technology (shanghai) corporation, a 7-channel independent 16bit adc is integrated inside, the sampling rate can reach 28.8kHz, data exchange is performed between the chip and the MCU through the SPI, and the communication rate can reach 10 Mbps; the terminal AVCC is connected with a power supply through a resistor R43 and is grounded through a capacitor C89 and a capacitor C96 which are connected in parallel, the terminal REFCAP is grounded through capacitors C17 and C20 which are connected in parallel, the terminal VCC is grounded through a capacitor C77, the terminal VDD is grounded through a capacitor C23 and a capacitor C25 which are connected in parallel, and the terminal DOUNT, the terminal DIN, the terminal SLCK and the terminal CS are connected with the MCU main chip HT 6025. After the voltage VD7022 of the metering chip is serially connected with a resistor R43 of 10 ohms, C89 and C96 are input into AVCC after filtering and shaping, the REFCAP pin is filtered by a capacitor CA17 and a capacitor CA20, the stability of the reference voltage is ensured,

in this embodiment, the working power supply VDD and VCC of the metering chip are designed with the REFCAP pin, and are introduced after being filtered by the input power supply. Selecting the level state of a pin by a phase line of a chip; the design of the whole circuit is important, and the high level output of the SEL pin of each chip must be measured; the SLE pin is directly connected with a power supply of the metering chip.

Specifically, as shown in fig. 5, the communication module includes an RS485 communication circuit and an RS232 communication circuit; the RS485 communication circuit and the RS232 communication circuit are connected with the microprocessor control module through a jumper terminal UART; the RS485 communication circuit comprises an isolation circuit and an RS485 communication chip U15, and the RS485 communication chip U15 is connected with a jumper terminal UART through the isolation circuit; the RS232 communication circuit comprises an RS232 communication chip U16 and peripheral circuits. The model of the RS485 communication chip U15 is BL 3085A; the RS232 communication circuit comprises an RS232 communication chip U16, and the model of the RS232 communication chip U16 is MAX 232. The line loss acquisition equipment of the embodiment provides high-speed standard RS485 and RS232 communication interfaces; the standard rate of the communication rate is 4800bit/s, 9600bit/s, 19200bit/s and 38400 bit/s; the interface communication follows DL/T634.5101-2002 protocol. The RS485 communication circuit comprises an RS485 communication interface of a high-speed isolation optocoupler, and the communication speed can reach 38400bps at most. The circuit design mainly considers the characteristics of the optical coupler, and the design of R30, R31, R32, R33 and R34 is very important, so that the communication quality is ensured at high temperature. The TVS is designed to protect differential mode surge voltage, the voltage is clamped at 6.8V, and the circuit is prevented from being damaged by overvoltage. ) The RS232 communication circuit selects RS485 communication and RS232 communication through jumper UART and COM, only supports one communication mode through the jumper UART, and the RS232 adopts TVS with model SMBJ22CA to restrain bus common mode interference.

The embodiment of the utility model provides a line loss collection equipment's overall dimension does: 107mm (length) × 84mm (width) × 42mm (thickness), the appearance structure and the installation dimension of the device meet the internal installation requirements of the distribution automation feeder terminal, and the device has the advantages of small volume, high precision, good reliability, convenient installation, capability of configuring line system parameters on site according to practical application and the like. The equipment module provides various external error verification interfaces, data acquisition interfaces and communication interfaces, can realize the error precision of the line loss module to be detected in advance and the error precision of the line loss module to be detected in the using process, greatly ensures the source tracing basis of the field application power distribution terminal to the line loss metering error precision, and provides important data support for the tracing judgment of the power enterprise to the line loss metering accuracy. In addition, the design has the active and reactive electric energy metering functions of 1-path alternating current, and the metering precision can reach 0.5S level and the highest 0.2S level. The three-phase four-wire or three-phase three-wire voltage input interface and the current signal input interface (the maximum secondary side of the high-voltage transformer is 10A/1S) can realize accurate metering of three-phase electric energy. The module can measure the active power, reactive power, power factor, split-phase voltage, split-phase current, frequency and other operation parameters of each split phase of 1 circuit of three-phase electric energy, and the measurement error is not more than +/-0.5%. The standard reference voltage Un can be classified as: 3 × 57.7/100V, 3 × 220/380V, 3 × 100V, 3 × 220V, and the standard reference current In can be classified as: 1A and 5A. The voltage measuring range is 0.05 Un-1.2 Un, and the current measuring range is 0.02 In-1.2 Imax. The line loss module is provided with a high-brightness long-life LED indicating lamp, can visually observe the equal-proportion electric energy pulse output of active and reactive electric energy of each path, and is provided with a working power supply and an operation indicating lamp, so that the operation condition of a product can be observed conveniently in the use process of a client. The module possesses high accuracy real-time clock circuit, and the design adopts MCU inside to possess the clock that realizes temperature compensation automatically, and output frequency is 1Hz, and the clock has calendar, timing, leap year automatic transformation function. The clock circuit is provided with an environment-friendly lithium battery, the standby power supply does not need to be replaced in the service life cycle of the module due to line loss, and the correct working time of the internal clock can be maintained to be more than 5 years after the module is powered off. The module can select a standard RS232/RS485 communication interface to realize data exchange with the power distribution terminal, thereby greatly facilitating the loss management of the power distribution line.

The utility model discloses in can placing in the box at distribution feeder terminal in, the mode that adopts the plug will be arranged in the voltage and current signal access distribution line of measurement decreases collection module, supports the hot plug, adopts the shielded cable, can realize independent measurement, check-up function. The accuracy requirement of active power conforms to the regulation in GB/T17215.322-2008, and the accuracy requirement of reactive power conforms to the regulation in GB/T17215.323-2008.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art.

Claims

1. The line loss acquisition equipment for the distribution automation feeder terminal is characterized by comprising a power supply module, a microprocessor control module, a storage module, a communication module and a metering module, wherein the power supply module is used for outputting direct-current voltage to supply power to the microprocessor control module, the communication module and the metering module; the microprocessor control module comprises an MCU main chip HT6025, a pin LVDIN of the MCU main chip HT6025 is connected with the anode of the 5V direct-current power supply through a resistor R6, and is grounded through a resistor R7 and a capacitor C1 respectively; a pin TEST of the MCU main chip HT6025 is connected with the anode of the 3V direct-current power supply through a pull-up resistor R8 and is grounded through a capacitor C3; pin RESET of the MCU main chip HT6025 is grounded via a capacitor C1, pin SGND is grounded, pin VSYS is connected to the positive electrode of the 3.3V dc power supply, and is also grounded via a capacitor C7.

2. The distribution automation feeder terminal line loss collection device of claim 1, wherein the microprocessor control module further comprises a crystal oscillator Y2, and two ends of the crystal oscillator Y2 are respectively connected with pin OSCI and pin OSCO of the MCU master chip HT 6025; the capacitance values of the capacitor C4 and the capacitor C3 are 0.1uF and 0.01uF respectively, the resistance value of the pull-up resistor R8 is 1K omega, and the resistance values of the resistor R6 and the resistor R7 are 100K omega and 63K omega respectively.

3. The distribution automation feeder terminal line loss acquisition device of claim 1, wherein the power module comprises a first power conversion circuit, a second power conversion circuit and a third power conversion circuit, the first power conversion circuit comprises a voltage dependent resistor YG, a capacitor C101, a diode D4, a power module U1 and a capacitor C2, the voltage dependent resistor YG and the capacitor C101 are connected in parallel between a positive input 48V dc voltage and ground, the positive input 48V dc voltage is connected to a pin Vin of the power module U1 via a diode D4, the pin Vout of the power module U1 serves as a 5V power output terminal of the first power circuit to output 5V dc voltage to the second power conversion circuit and the third power conversion circuit, and the capacitor C102 is connected between the pin Vout of the power module U1 and ground;

4. The distribution automation feeder terminal line loss collection device of claim 3, wherein the power module U1 is model ZY4805WHBD-3W1, the power module U2 is model ZY0505IFS-1W, the power module U4 is model S1206B33, and the output power of the battery BAT is 3.6V.

5. The distribution automation feeder terminal line loss collection device of claim 1, wherein the metering module comprises a metering chip, a voltage sampling circuit and a current sampling circuit, and an output of the voltage sampling circuit and an output of the current sampling circuit are connected with an input of the metering chip.

6. The distribution automation feeder terminal line loss acquisition equipment as claimed in claim 5, wherein the voltage sampling circuit comprises three current type voltage transformers and three voltage sampling filter circuits, each phase voltage is respectively connected with the input end of the current type voltage transformer after passing through a high-precision non-inductive resistor, the output end of the current type voltage transformer is respectively connected with one channel of the metering chip ATT7022E after passing through one sampling filter circuit, the voltage sampling filter circuit comprises a resistor R38, a resistor R42, a capacitor 19 and a capacitor C22, after the resistor R38 is connected with the capacitor C19 in parallel, one end of the resistor R is connected with the output end of the current type voltage transformer and one voltage channel pin VP of the metering chip, and the other end of the resistor R3838 is connected with the ground; after the resistor R42 is connected with the capacitor C22 in parallel, one end of the resistor R42 is connected with the ground, and the other end of the resistor R42 is connected with a pin VN of the same voltage channel of the metering chip;

7. The distribution automation feeder terminal line loss collection device of claim 1, wherein the communication module comprises an RS485 communication circuit and an RS232 communication circuit; the RS485 communication circuit and the RS232 communication circuit are connected with the microprocessor control module through a jumper terminal UART; the RS485 communication circuit comprises an isolation circuit and an RS485 communication chip U15, and the RS485 communication chip U15 is connected with a jumper terminal UART through the isolation circuit; the RS232 communication circuit comprises an RS232 communication chip U16 and peripheral circuits.

8. The distribution automation feeder terminal line loss collection device of claim 7, wherein the RS485 communication chip U15 is model number BL 3085A; the RS232 communication circuit comprises an RS232 communication chip U16, and the model of the RS232 communication chip U16 is MAX 232.

9. The distribution automation feeder terminal line loss collection device of claim 1, wherein the storage module comprises an EEPROM memory, and the EEPROM memory is connected with the MCU master chip HT6025 through IIC.

10. The distribution automation feeder terminal line loss collection device of claim 1, wherein the microprocessor control module further comprises a program download and debug interface ISP, the program download and debug interface ISP being connected to pin TMS, pin TCK and pin TEST of MCU master chip HT6025, and further being connected to 3.3V dc positive voltage and GND ground.