CN105449686A - Intelligent reactive power compensation and electric energy parameter display integrated control device - Google Patents

Abstract

The invention discloses an intelligent reactive power compensation and electric energy parameter display integrated control device, and the device comprises a microprocessor unit, a signal collection unit, an electric energy parameter analysis metering unit, a power supply unit, a display unit, a man-machine conversation unit, a storage unit, an alarm unit, a temperature detection unit, a communication unit, and a drive output unit. The device integrates power grid monitoring and reactive power compensation, can compensate for the reactive loss of a power grid, improves the power factor, reduces the line loss, and improves the loading capability and power supply quality of the power grid. Meanwhile, the method also can monitor three-phase voltage and current and the power factor of the power grid in real time, can complete the integrated management of the monitoring, analysis and processing, report output and remote operation of a whole low-voltage power distribution line, and provides the first-hand reliable data for the scientific management of the low-voltage power distribution line.

Description

Intelligent reactive power compensation and electrical energy parameter display composite control apparatus

Technical field

The invention belongs to electric power quality control technology and energy-conserving and environment-protective technology neck field, particularly a kind of intelligent three-phase low-voltage alternating-current dynamic reactive power compensation and three-phase electric energy parameter display integrated control method and device.

Background technology

Along with the raising of expanding economy and people's living standard, all trades and professions are had higher requirement to power supply reliability and power supply quality.Because power distribution network is in the end of electrical network, user mostly is low-voltage customer, the power factor of many electrical appliances is very low, and be not with compensation arrangement, this brings very large power burden and extra line loss to electrical network, in order to safeguard power system stability, ensure the quality of power supply and safe operation, local reactive power compensation is carried out to electrical network end transformer and just seems and be necessary very much.

Reactive power compensation device is that one can be stablized line voltage, improves electrical network three-phase imbalance, saves energy, raising transformer increase-volume utilance, meet increase-volume demand, eliminates electromagnetic pollution and improves the device of Electrical Safety reliability.At present, traditional low-pressure reactive compensation equipment be generally gather single signal, low voltage parallel capacitor group adopts delta connection mostly, reactive power compensation is static compensation, make the switching executive component of power capacitor with A.C. contactor, during input, impulse current is large, produces overvoltage during excision, not only can cause interference to electrical network, and affect capacitor useful life.Self contact rapid wear, noise is melting welding greatly even, and the switching time is long.Controlling unit can not be accomplished phase-splitting, classification, fast and the requirement of tracing compensation substantially.General employing power factor type in physical quantity control mode, this control mode is also very traditional mode, and sampling, control are also all easier to realize.This sample mode is in operation and should ensures that line system is stable, dead-beat phenomenon occurs, take into account compensation effect again, this is conflict, can only be worked under good state by parameter tuning depending on concrete condition at the scene.Even if adjustment is relatively good, the defect of this mode itself also cannot be complemented when circuit heavy load.

Switching mode is fixed mode switching cycle, coding switching.Controlling unit can not be accomplished phase-splitting, classification, fast and the requirement that compensates of intelligent-tracking substantially.

Summary of the invention

The object of the invention is to overcome the defect existed in prior art, a kind of integration unit with intelligentized reactive power automatic compensation and electrical energy parameter display is provided, have employed grace intelligence Pu LPC1114FBD48/301ARM32 bit microprocessor, and high accuracy 16 A/D threephase AC electric energy chip ATT7022B, carry out detection of grid reactive power, MCU calculates the capacity of required building-out capacitor according to idle amount, and controller drops into electric capacity successively.Controller drops into be adopted in two ways, and a kind of mode arranges every road capacitor's capacity voluntarily for user, and another kind is for recommend RCE-1 switching to encode to user, and when adopting this mode, capacitance cannot be arbitrarily given; Voltage sampling signal is obtained by resistance-capacitance depressurization in civil power, and current signal is obtained by D.C mutual-inductor, and be shown as 12864 band Chinese word library liquid crystal, user profile and parameter are kept at AT24c02I ²c serial CMOSE ²in this sheet chip of PROM; Clock chip is PCF8583, and this chip has I ²c bus, can provide correct time record for system, after power down, battery continues chip power supply for this reason, chip self-clocking; Digital temperature sensor DS18B20, energy is testing environment temperature accurately, and when occurring that temperature is too high, in order to ensure power grid security, avoid fire, controller will automatically lock, and can not carry out any operation; Communication can adopt RS485 to communicate, and controller can carry out networking, and every platform controller has oneself address, and monitor staff is by the controling parameters of upper computer software supervisory control device; Controller by the idle amount of detection of grid, and in conjunction with power factor, carries out the switching of electric capacity, and switching algorithm is PID ratio, differential, integral control algorithm, and this algorithm is classical industrial control equipment algorithm.

Host computer operation interface (VC++2008 development platform), can make development interface attractive in appearance, creation database.Upper computer software can provide real-time monitor data for user, and various data and curves.Integrate power network monitoring and reactive power compensation, not only can reactive loss in compensation network, improve power factor, reduce line loss, thus improve load capacity and the power supply quality of electrical network; Simultaneously can also the service data such as three-phase voltage, electric current, power factor of Real-Time Monitoring electrical network, can complete the integrated managements such as the monitoring to whole low-voltage distributing line, analyzing and processing, report output, the scientific management for low-voltage distributing line provides first hand authentic data.

Technical scheme of the present invention comprises following content.

Physical quantity control mode adopts reactive power (reactive current) type, the defect solving power factor type that the controller of reactive power (reactive current) type is more perfect.It has four quadrant operation, automatically, manual switchover, self-identifying each road Capacitor banks power, automatically to regulate switching time, harmonic wave over voltage alarm and protection, warnings of circuit resonance, overvoltage protection, warnings of circuit low current, voltage, current distortion rate to measure, show capacitor power, show cos Φ, U, I, S, P, Q and frequency according to load.

The current signal that current transformer on access distribution network system bus exports converts weak current signal Ia1, Ib1, Ic1 to through current sensor respectively, voltage sampling signal obtains low voltage voltage signal Ua1, Ub1, Uc1 by resistance-capacitance depressurization, and the electric current of homophase and voltage signal are all that synchronous acquisition completes.

Three-phase current after gathering and voltage signal are transported to three-phase electrical energy computation chip and deliver to microprocessor after computings.

Microprocessor shows needing the electrical energy parameter of display to deliver to liquid crystal display, electrical energy parameter is delivered to storage chip simultaneously and is stored, so that user calls at any time.

Clock chip PCF8583 passes through I ²c bus and microprocessor communication, ensure the accuracy of time.

Most of reactive power compensator can only cannot realize remote monitoring and management as an independent equipment use, microprocessor and 485 chip communications, apparatus of the present invention are made to have network communicating function, can realize at a distance the integrated management such as combining to the monitoring, analyzing and processing, report output, remote operation etc. of whole low-voltage distributing line, the scientific management for low-voltage distributing line provides first hand authentic data.

Adopt the accurate testing environment working temperature of digital temperature sensor, when occurring that temperature is too high, in order to ensure power grid security, avoid fire, controller will automatically lock, and can not carry out any operation.

Accompanying drawing explanation

Fig. 1 entire block diagram

Fig. 2 voltage sample schematic diagram

Fig. 3 current sample schematic diagram

Fig. 4 electric energy computation chip and Microprocessor Interface schematic diagram

Fig. 5 microprocessor connects schematic diagram with HC595 driving chip

Fig. 6 storage chip AT24C512 connects schematic diagram with microprocessor

Figure 74 85 communication interface schematic diagram

Fig. 8 liquid crystal display connects schematic diagram with microprocessor

Fig. 9 main program flow chart

Figure 10 ATT7022 data sampling and calibration software flow pattern

Figure 11 three-phase current sample circuit principle detail drawing

Figure 12 three-phase voltage sample circuit principle detail drawing

Figure 13 exports and controls electric principle detail drawing

Figure 14 ATT7022 chip internal block diagram.

Specific embodiments

Do one below in conjunction with accompanying drawing to elaborate.Three phase mains transformer in FIG (1)output export after (2) threephase current transformer converts 0-5A to the current detecting in detecting unit (4) with voltage detecting (5), current detecting adopts TA12 current sensor, and its no-load voltage ratio is 1000:1, input current 0-5A, output current 0-5mA; Voltage detecting adopts resistance pressure-dividing network; The three-phase current detected and voltage signal deliver to electric energy detection chip AT7220(6) A/D port.Be integrated with 16,6 tunnel A/D converter at ATT7022 chip internal, current channel effective value is less than 0.1% in the scope internal linear error of 2mV to 1V; Voltage channel effective value is less than 0.1% in the scope internal linear error of 10mV to 1V; Voltage value is at 0.2V to 0.6V, and (voltage sampling signal is less than 0.2V, voltage available passage ADC gain selection, the amplification by suitable for sampled signal), On The Current Value is at 2mV to 1V, and electric energy linearity error is less than 0.1%.Can see that three-phase current is input to VxP, VxN port of ATT7022 respectively respectively after CT1/CT2/CT3 tri-current sensors in figure 3, the while that IA, IB, IC, IN being the primary side signals of current sensor, VxP, VxN need superposition about 2.4V DC offset voltage, this bias voltage can be obtained by 11 pin output reference voltage REFOUT of chip, can certainly be provided by external reference voltages.

Voltage sample input adopts electric resistance partial pressure mode as Fig. 2, the reference voltage of zero line VN and chip exports REFO and links up, bias voltage is provided by the 11st pin REFOUT of chip, achieve easily by ac sampling signal superposition on the bias direct current of 2.4V, VA, VB, VC and VN access live wire and the zero line of line voltage.

For ensureing certainty of measurement, external filter capacitor 10uF and 0.1uF of chip the 5th pin should try one's best near pin place in figs. 2 and 3, and order two electric capacity all can not save.The earth point of electric capacity should with short as far as possible the connecting together of the ground wire of sampled signal.

In VxP and VxN input circuit, resistance-capacitance network constitutes frequency overlapped-resistable filter in figs. 2 and 3, and its structure and parameter will be particular about symmetry, and adopts the good components and parts of temperature performance, thus ensures the temperature characterisitic that ammeter obtains.

Fig. 4 is that ATT7022 connects schematic diagram with microprocessor, ATT7022 and microprocessor have 6 lines, and wherein 4 is SPI mouth line, and wherein CS is chip selection signal, SCLK is serial clock input, DIN is serial date transfer, and DOUT is that serial data exports, and also having two is reset control line RESET respectively, handshake line SIG, because all signal high level of ATT7022 are 5V, when the single-chip microcomputer line with 3V power work, centre should connect level shifting circuit.

For preventing interference signal on the impact of SPI transmission signal line, 10 Ω resistance that SPI holding wire is all connected, this resistance combines with the parasitic capacitance C of IC input can form a low pass filter, thus can eliminate the High-frequency Interference of acknowledge(ment) signal.Under the condition that SPI communication speed allows, add a decoupling capacitor Ca/Cb/Cc/Cd, to strengthen antijamming capability at the input of holding wire.

Microprocessor must to SIG signal or its monitoring state.To power on or ATT7022 is disturbed reset, must upgraded calibration data by SPI mouth by outside MCU, to ensure the accuracy of measuring.SIG signal is just used to the handshake notifying outside MCU.Connect the decoupling capacitor of 10nF in the SIG port of ATT7022, strengthen its antijamming capability.This circuit adopts the bit16 whether set of testing status register, determines that calibration data are the need of renewal.

In order to power on and microprocessor reset after, ATT7022 can be synchronous with microprocessor work, the RESET signal demand of ATT7022 is by Microprocessor S3C44B0X, and reseting procedure is that RESET signal keeps being greater than 30ns low level, chip reset, now SIG exports high level, then RESET signal is drawn high by microprocessor, approximately completes initialization through about 500us, ATT7022, SIG output low level signal, after this just can carry out SPI operation.The RESET port of ATT7022 is connected to reset circuit resistance Rs and electric capacity Cs in the diagram.

Fig. 5 is driver output circuit block diagram, and 74HC595 is 8 Bits Serial I/O or parallel output shift register chip, SI (14 pin): serial data input.SCK (11 pin): the data shifts of data register during rising edge, trailing edge shift register data is constant.(pulse duration: during 5V was greater than for tens nanoseconds just.) RCK (12 pin): during rising edge, the data of shift register enter data storage register, and during trailing edge, memory register data are constant.(usually RCK being set to low level), when after end-of-shift, holds generation positive pulse (during 5V, to be greater than for tens nanoseconds just at RCK.), upgrade display data.OE (13 pin): forbid during high level exporting (high-impedance state), can produce flicker easily and extinguish effect.In Fig. 5,11/12/13/14 pin of 74HC595 connects with microprocessor, and work is carried out in the order accepted from microprocessor, and the output signal of 74HC595 exports to load after the buffer circuit be made up of optocoupler, and this load is intelligent composite AC contactor.

Fig. 6 is AT24C02 is that the 2K serial electricity that Atmel company produces clashes programmable memory, it adopts 8 pin package, there is the features such as compact conformation, memory capacity are large, 4 chips can be connect in 2 line buses, be specially adapted to have the data acquisition system that mass data storage requires.A0/A1/A2 address choice input in figure 6, SDL bi-directional serial data input and output day.For the exchanges data between memory and microprocessor.SCL serial clock inputs.Usually rise along by the writing data into memory on SDL thereon, and be sent to SDL at trailing edge from memory sense data.WP write-protect inputs.Because AT24C512 has followed the interface features of AT24C series, therefore also cry with the connection of microprocessor and follow conventional method.General A0/A1/A2/WP meets VCC or GND, and the P1 mouth that SDL/SCL connects microprocessor can realize the operation of microprocessor to AT24C512.

In Fig. 6, IST1208 is that INTERSIL company band backup battery is powered the low-power consumption real-time timepiece chip of SRAM, and oscillator adopts the crystal of the 32.768kHz of outside low cost.Real-time clock with independently time, the minute, second register tracing time, and order also with calendar register for storing day, the moon, year and week.Its 1 pin is the input of inverting amplifier, the pin being connected to outside 32.768kHz quartz product body also can directly be driven with the crystal source of 32.768kHz, 2 pin are outputs of sign-changing amplifier, to be connected to another pin of outside 32.768kHz quartz crystal, 3 pin provide back-up source voltage for device.When VDD power-fail, VBAT is that device is powered.This pin is not used time ground connection, 4 pin ground connection, 5 pin are bi-directional pin serial datas (SDA), for by serial date transfer or output device, 6 pin serial clock (SCL) inputs are used as the clock sync signal of data input and output, 7 pin interrupt output/frequency output terminals are multi-functional, not only can be used as interrupt output pin but also can be used as rate-adaptive pacemaker pin.Its pin function is set by configuration register, 8 pin VDD power supplies.Wherein clock input port SCL, data input/output port SDA are connected with P1.6, P1.7 leg of microprocessor respectively, and Vbat pin connects backup battery.SDA and SCL must have pull-up resistor to power supply.When external power source is normal, main power source+5V is charged to electric capacity CC1 by diode DC1.When main power voltage than at least low 50mV of the voltage of back-up source and main power voltage lower than 2.2V time, back-up source starts to power to ISL1208.

Fig. 7 is 485 telecommunication circuits, the interface chip of RS485 adopt MAXIM (U.S. letter) company MAX3485. this be a full duplex 485 transceiver, have hot plug protection, network failure is protected, esd protection, and its pin function is as follows:

Pin1-RO: receiver exports

Pin2-RE: receiver output enable (Low level effective)

Pin3-DE: driver output enable (high level is effective)

Pin4-DI: driver inputs

Pin5-GND: connect ground

Pin6-A: driver exports receiver input (homophase)

Pin7-B: driver exports receiver input (anti-phase)

Pin8:Vcc

Microprocessor uses RS485 communication, and can use full and half duplex two kinds of patterns, the present invention adopts half-duplex fairly simple.MAX3485 adopts general serial mouth, increase a sending/receiving and control mouth (called after RS485R/T), microprocessor TXD is met the DI of MAX3485, microprocessor RXD meets the RO of MAX3485, RE and DE of MAX3485 is connected on MAX3485R/T, when MAX3485R/T is high, is allow serial communication input, for time low, allow Serial output.MAX485 exports as A, B differential signal, so stronger than RS232 antijamming capability, transmission range is far away relative to RS232.Generally we use and often will adopt Phototube Coupling, to ensure reliability.Export termination 2 P6KE15CA Transient Suppression Diodes at MAX3485, it is a kind of over-voltage protector of votage limit type, and it is limited in too high abnormal Electricity pressure with the speed of pS Grade the Inner of one Ge safe range, From and play protection circuit below and be not subject to Damage not bad.P6KE15CA Transient Suppression Diode is placed between holding wire and ground connection, data and control bus can be avoided to be subject to unnecessary noise effect.

Fig. 8 is that microprocessor connects schematic diagram with 128X64 liquid crystal driver module, LCD MODULE adopts the JM1286401 pattern block of Jun Xian Electronic Science and Technology Co., Ltd. of Shenzhen, module interface mode is simple, complete Chinese man-machine dialog interface can be formed, can show the capable 16X16 dot character of 8X4, Module Price is more similar on the low side.Pin function above liquid crystal display is as follows:

Pin1vss ground

Pin2VDD power supply+5V

The brilliance control of Pin3VO contrast

Pin4RS: instruction or data selection instruction or data selection RS=1 operating data, RS=0 operational order code;

Pin5R/S: read/write selects R/S=1 read operation, R/S=0 write operation;

Pin6E: input enable;

Pin7-14DB0-DB7: data/address bus

Pin15,16 chip selection CS1, CS2: be chip select signal A, B, CS1, CS2=1, gating row drive left and right half part, CS1, CS2=0, and gating row do not drive left and right half part;

Pin17RST: reset terminal Low level effective

Pin18VOUTLCD driving voltage exports

Pin19LEDA LCD backlight anode+5V

Pin20LEDK LCD backlight negative terminal

LCD MODULE is connected with microprocessor sees Fig. 8.

Fig. 9 is main program flow chart, and Figure 10 is ATT7022 data sampling and calibration software flow pattern, and software adopts C language to write.

Figure 11 is three-phase current sample circuit schematic diagram, can see that three-phase alternating-current supply is the V1P/V1N/V3P/V3N/V5P/V5N respectively by sending into electric energy chip AT7022 after 3 current transformer cd2/cd3/cd4 in the drawings; Figure 12 is three-phase voltage sample circuit schematic diagram, can see that three-phase alternating-current supply is the V2P/V2N/V4P/V4N/V6P/V6N respectively by sending into electric energy chip AT7022 after 3 resistor networks in the drawings; Figure 13 exports to control electrical schematic diagram, Microprocessor S3C44B0X 28 Bits Serial I/O or parallel output shift register 74HC595, then output signal controls combination switch after light-coupled isolation; Figure 14 is ATT7022 chip internal block diagram.

Claims (6)

1. Intelligent reactive power compensation and an electrical energy parameter display composite control apparatus, is characterized in that: it comprises microprocessor unit (9) signal gathering unit and comprises three-phase current sensor (4) and detecting voltage by three phase circuit (5) electrical energy parameter analysis metering units (6) power conversion unit (3) display alarm unit (12) human-computer dialogue unit (11) memory cell (10) digital temperature detecting unit (6) 485 communication unit (13) driver output unit (14) Phototube Coupling unit source (15) power stage unit (16); Described signal gathering unit comprises current sampling circuit (4) and is connected with threephase current transformer with voltage sampling circuit (5), gather three-phase voltage and the electric current of three-phase alternating-current supply respectively, three-phase current after collection and voltage signal are sent to electrical energy parameter respectively and analyze metering units, after the computing of electric energy the special metering IC, be sent to microprocessor unit (9) by photoelectric isolating circuit (8); Display alarm unit (12) human-computer dialogue unit (11) memory cell (10) is connected with microprocessor unit (9), the instruction receiving microprocessor unit (9) is carried out showing, report to the police, read information in memory and by information stored in memory; 485 communication units (13) are connected with microprocessor (9), receive and transmission data under communication protocol commander; Driver output unit (14) is connected with microprocessor (9) and accepts its instruction and export control signal to photoelectric isolating circuit (15) and power output circuit (16), the drive singal control direct current signal that output one is stable after power output circuit (16) amplifies is given and is brought back to life switch (17), carries out switching by bringing back to life switch (17) to compensation condenser; Described power conversion unit (3) comprises AC220V translation circuit, DC power management module, and the galvanic current pressure exporting different electric pressure is supplied to unit and circuit by DC supply bus bus (18).

2. according to Intelligent reactive power compensation according to claim 1 and electrical energy parameter display composite control apparatus, it is characterized in that: described microprocessor is the grace intelligence Pu LPC1114FBD48/301ARM32 bit microprocessor adopted, its I/O mouth is connected with digital temperature sensor, receive the temperature signal from digital temperature sensor, the 2P/13P/26P/38P of electrical energy parameter metrical information in the SPI mouth of microprocessor after photoelectric isolating circuit isolation from three-phase alternating current the special metering IC AT7220 is connected, its I/O mouth is also respectively at memory cell, human-computer dialogue unit, display alarm unit, 485 communication units and driver element are connected, by software it controlled and communicate.

3. Intelligent reactive power compensation as claimed in claim 1 and electrical energy parameter display composite control apparatus, is characterized in that, described electrical energy parameter analysis metering have employed three-phase alternating current the special metering IC AT7220.

4. three-phase current sampling employing three current transformers, A/B/C three-phase current respectively by CT1/CT2/CT3 tri-current sensors, by gather three-phase current signal send into the 3P/4P/6P/7P/9P/10P of three-phase alternating current the special metering IC AT7220 respectively; Three-phase voltage have employed three resistance step-down potential-divider networks, by gather three-phase current signal send into the 13P/14P/16P/17P/19P/20P of three-phase alternating current the special metering IC AT7220 respectively, electric current and voltage acquisition be all three-phase alternating current instead of single-phase or wherein two-phase, substantially increase the accuracy of data display and process.

5. Intelligent reactive power compensation as claimed in claim 1 and electrical energy parameter display composite control apparatus, it is characterized in that, have employed DS18B20 digital temperature sensor and gather building-out capacitor temperature, the temperature signal of collection send into realize temperature after microprocessor processes display, control and warning.

6. Intelligent reactive power compensation as claimed in claim 1 and electrical energy parameter display composite control apparatus, is characterized in that, have employed AT24c02I ²c serial CMOSE ²pROM, microprocessor and it carry out two-way communication sense data to microprocessor, the related data of microprocessor processes is written to memory and deposits.