CN113541155A - Adaptive factory power factor universal compensation method and device - Google Patents
Adaptive factory power factor universal compensation method and device Download PDFInfo
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- CN113541155A CN113541155A CN202110698462.5A CN202110698462A CN113541155A CN 113541155 A CN113541155 A CN 113541155A CN 202110698462 A CN202110698462 A CN 202110698462A CN 113541155 A CN113541155 A CN 113541155A
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- 238000005259 measurement Methods 0.000 claims description 5
- 238000006243 chemical reaction Methods 0.000 claims description 3
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
- H02J3/1821—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators
- H02J3/1835—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control
- H02J3/1864—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control wherein the stepless control of reactive power is obtained by at least one reactive element connected in series with a semiconductor switch
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/26—Arrangements for eliminating or reducing asymmetry in polyphase networks
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/30—Reactive power compensation
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/50—Arrangements for eliminating or reducing asymmetry in polyphase networks
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Abstract
The invention relates to a universal power factor compensation method and a universal power factor compensation device for a self-adaptive factory, wherein the method comprises the following steps: and (3) real-time acquisition and calculation: collecting the voltage and current of a three-phase circuit in real time, and calculating the power factor of each phase; rough compensation: roughly compensating the three-phase circuit by adopting an integral switching capacitor group; and (3) precise compensation: and the capacitor group for single switching is adopted to carry out single-phase accurate compensation on the compensation capacitor required by each phase. Compared with the prior art, the method can effectively compensate the power factor, and has stronger self-adaptability and higher automation degree.
Description
Technical Field
The invention relates to the technical field of electric energy quality, in particular to a power factor universal compensation device for a self-adaptive factory.
Background
The conventional electric energy quality compensation device in the market can improve the power factor to a certain extent and improve the electric energy quality, but cannot perfectly deal with the three-phase unbalanced state of a three-phase circuit of a factory power grid, and cannot perform further accurate compensation. For large plants with large power consumption, the improvement of the quality of the electric energy can significantly reduce the operating cost. In a large-scale factory, the quality of a power grid of a power supply system is not stable all the time, and a power factor reduction or three-phase imbalance condition can be caused over time, so that the detection and automatic repair of the power grid condition are particularly important. Due to the defects of the existing compensation device, a short plate with poor self-adaptability exists in the device for compensating the reactive power.
Disclosure of Invention
The present invention aims at providing a universal power factor compensation method and device for adaptive factories to overcome the defects of the prior art.
The purpose of the invention can be realized by the following technical scheme:
an adaptive factory power factor universal compensation method, comprising:
and (3) real-time acquisition and calculation: collecting the voltage and current of a three-phase circuit in real time, and calculating the power factor of each phase;
rough compensation: roughly compensating the three-phase circuit by adopting an integral switching capacitor group;
and (3) precise compensation: and the capacitor group for single switching is adopted to carry out single-phase accurate compensation on the compensation capacitor required by each phase.
Preferably, the rough compensation is specifically performed by: the three capacitors are connected into a triangle and are simultaneously connected into a three-phase circuit.
Preferably, the precise compensation is realized in a specific manner as follows: each phase is respectively provided with a plurality of groups of parallel capacitors with different sizes, and the parallel capacitors with corresponding sizes are switched into the corresponding phases according to the sizes of the compensation capacitors required by each phase.
An adaptive factory-used power factor universal compensation device, comprising:
the acquisition circuit: collecting voltage and current of a three-phase circuit;
the control circuit: calculating power factors of all phases in the three-phase circuit, and controlling the switching of the capacitor bank to perform power factor compensation control;
the compensation circuit: the three-phase single-circuit capacitor bank comprises an integral switching capacitor bank and an independent switching capacitor bank, and is used for performing rough compensation and accurate compensation of a three-phase single circuit respectively.
Preferably, the acquisition circuit comprises:
a step-down collector: the voltage reduction acquisition device is used for carrying out voltage reduction acquisition on each phase voltage and comprises a voltage divider and a voltage follower which are connected in sequence;
a current collector: the current transformer, the conversion resistor, the operational amplifier and the voltage follower are sequentially connected;
a dead time measurement circuit: for measuring the time of the current lag voltage of each phase.
Preferably, the dead time measuring circuit includes first zero-crossing comparator, second zero-crossing comparator and exclusive-or gate, the positive pole of first zero-crossing comparator input be the voltage waveform, first zero-crossing comparator input negative pole ground connection, the positive pole of second zero-crossing comparator input be the current waveform, the negative pole ground connection of second zero-crossing comparator input, the output of first zero-crossing comparator and second zero-crossing comparator all be connected to the input of exclusive-or gate, the high level time of the output of exclusive-or gate is the time of current waveform dead time voltage waveform.
Preferably, the control circuit:
a phase difference calculation module: calculating the phase difference between the voltage and the current according to the time of the lagging voltage waveform of the current waveform;
the compensation capacitance calculation module: calculating and compensating the capacitance value of each phase compensation capacitor according to the phase difference;
a coarse compensation control module: the three-phase circuit is roughly compensated by adopting an integral switching capacitor set during primary compensation;
the accurate compensation control module: and the compensation capacitor group is used for carrying out single-phase accurate compensation on compensation capacitors required by each phase by adopting a capacitor group for single switching after the first compensation.
Preferably, the control circuit takes a single chip microcomputer as a core to perform compensation control.
Preferably, the capacitor bank for integral switching specifically comprises: the three capacitors are connected into a group to form a triangle and are connected into the three-phase circuit in parallel.
Preferably, the capacitor bank for individual switching specifically comprises: each phase is provided with a plurality of groups of parallel capacitors with different sizes.
Compared with the prior art, the invention has the following advantages:
(1) the invention realizes one-time rough compensation and multiple-time precise compensation through multiple sampling, gradually approaches to a final higher power factor, better deals with the condition of three-phase unbalanced state of a power grid circuit through three-phase integral compensation and single-phase respective compensation, and has stronger self-adaptability and higher automation degree.
(2) The universal compensation device can be widely applied to large-scale factories, has stronger self-adaptability and higher automation degree, can greatly reduce operation and maintenance cost and save energy while effectively improving power factor and power grid quality, can perform more accurate capacitance switching compensation when a circuit has three-phase unbalance, and has wider application compared with the similar compensation devices.
Drawings
FIG. 1 is a block diagram of a flow chart of a universal compensation method for power factor of an adaptive factory according to the present invention;
FIG. 2 is a schematic circuit diagram of the buck collector of the present invention;
FIG. 3 is a circuit diagram of a rectifying-filtering circuit according to the present invention;
FIG. 4 is a schematic circuit diagram of the current collector of the present invention;
FIG. 5 is a circuit schematic of the dead time measurement circuit of the present invention;
FIG. 6 is a schematic circuit diagram of the capacitor bank for integral switching according to the present invention;
fig. 7 is a schematic circuit diagram of the capacitor bank for individual switching according to the present invention.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. Note that the following description of the embodiments is merely a substantial example, and the present invention is not intended to be limited to the application or the use thereof, and is not limited to the following embodiments.
Examples
As shown in fig. 1, the present embodiment provides an adaptive universal compensation method for power factor for plant, the method includes:
and (3) real-time acquisition and calculation: collecting the voltage and current of a three-phase circuit in real time, and calculating the power factor of each phase;
rough compensation: roughly compensating the three-phase circuit by adopting an integral switching capacitor group;
and (3) precise compensation: and the capacitor group for single switching is adopted to carry out single-phase accurate compensation on the compensation capacitor required by each phase.
The specific way of rough compensation is as follows: the three capacitors are connected into a triangle and are simultaneously connected into a three-phase circuit.
The precise compensation method comprises the following specific steps: each phase is respectively provided with a plurality of groups of parallel capacitors with different sizes, and the parallel capacitors with corresponding sizes are switched into the corresponding phases according to the sizes of the compensation capacitors required by each phase.
After data acquisition is finished, the capacitor bank closest to the optimal capacitance value is calculated firstly, the capacitors are switched simultaneously through the three-phase circuit to carry out rough compensation, then secondary data acquisition and analysis are carried out, and small-amplitude accurate compensation is carried out on each phase in the three-phase circuit through data obtained through secondary analysis so as to achieve the purpose of finally achieving the highest overall power factor.
The embodiment also provides an adaptive factory power factor universal compensation device, which comprises:
the acquisition circuit: collecting voltage and current of a three-phase circuit;
the control circuit: calculating power factors of all phases in the three-phase circuit, and controlling the switching of the capacitor bank to perform power factor compensation control;
the compensation circuit: the three-phase single-circuit capacitor bank comprises an integral switching capacitor bank and an independent switching capacitor bank, and is used for performing rough compensation and accurate compensation of a three-phase single circuit respectively.
Specifically, the acquisition circuit includes:
1. a step-down collector: the voltage reduction acquisition device is used for carrying out voltage reduction acquisition on each phase voltage and comprises a voltage divider and a voltage follower which are sequentially connected.
As shown in FIG. 2, taking one of the three-phase circuits as an example, noise is reduced below the low voltage amplitude of 7V by a voltage divider (composed of R1-50k Ω and R2-1k Ω) through a voltage follower, and a corresponding voltage signal U1 is obtained. Fig. 3 shows a rectifying and filtering circuit, and a signal U1 acquired by the voltage acquisition circuit can be input into an analog-to-digital converter of the single chip microcomputer to calculate the amplitude value after passing through the circuit shown in the following figure.
2. A current collector: the device is used for collecting each phase of current and comprises a current transformer, a conversion resistor, an operational amplifier and a voltage follower which are connected in sequence.
As shown in FIG. 4, for example, in a three-phase circuit, the current collected after the single-phase current passes through two current transformers is I2 (10 of the phase current)-5Multiple), I2 flows through R2 to convert the current signal into a voltage signal, then the voltage is amplified by 25.1 times through an integrated operational amplifier and sent to a voltage follower to reduce noise, and the obtained U2 is a function of the current signal.
3. A dead time measurement circuit: for measuring the time of the current lag voltage of each phase. The lag time measuring circuit comprises a first zero-crossing comparator, a second zero-crossing comparator and an exclusive-or gate, wherein the positive pole of the input end of the first zero-crossing comparator is voltage waveform, the negative pole of the input end of the first zero-crossing comparator is grounded, the positive pole of the input end of the second zero-crossing comparator is current waveform, the negative pole of the input end of the second zero-crossing comparator is grounded, the output ends of the first zero-crossing comparator and the second zero-crossing comparator are both connected to the input end of the exclusive-or gate, and the high level time of the output end of the exclusive-or gate is the lag time of the current waveform.
FIG. 5 is a circuit diagram of the dead time measurement circuit, with V3 being the collected voltage waveform and V4 being the collected current waveform; the two signals are respectively sent to a zero-crossing comparator to obtain level signals U1 and U2, then U1 and U2 are input into an exclusive-OR gate, and finally the time when U0 and U0 are high levels is obtained and is the time of current lag.
The control circuit:
a phase difference calculation module: the phase difference of the voltage and the current is calculated according to the time when the current waveform lags the voltage waveform, and specifically, the phase difference can be expressed as:
wherein, TU0For current lag time, T is the voltage/current period;
the compensation capacitance calculation module: calculating and compensating the capacitance value of each phase compensation capacitor according to the phase difference;
specifically, before reactive power compensation is not performed, the complex impedance is: z ═ R + j ω · L, in this case,
t2 pi/ω, from which it can be derived:
assuming power factor compensation via capacitor C, the compensated complex impedance is denoted as Z':
obtaining by transformation:
in order to improve the power factor, ideally, the power factor is 1, the imaginary part of the complex impedance should be 0, and the power factor should be improved
The following equation can be obtained:
wherein,
a coarse compensation control module: the three-phase circuit is roughly compensated by adopting an integral switching capacitor set during primary compensation;
the accurate compensation control module: and the compensation capacitor group is used for carrying out single-phase accurate compensation on compensation capacitors required by each phase by adopting a capacitor group for single switching after the first compensation.
The control circuit takes the singlechip as a core to carry out compensation control.
As shown in fig. 6, the specific composition of the capacitor bank for overall switching is as follows: the three capacitors are connected into a group to form a triangle and are connected into the three-phase circuit in parallel.
As shown in fig. 7, the specific composition of the capacitor bank for individual switching is as follows: each phase is provided with a plurality of groups of parallel capacitors with different sizes.
The above embodiments are merely examples and do not limit the scope of the present invention. These embodiments may be implemented in other various manners, and various omissions, substitutions, and changes may be made without departing from the technical spirit of the present invention.
Claims (10)
1. An adaptive universal compensation method for power factor for factory is characterized by comprising the following steps:
and (3) real-time acquisition and calculation: collecting the voltage and current of a three-phase circuit in real time, and calculating the power factor of each phase;
rough compensation: roughly compensating the three-phase circuit by adopting an integral switching capacitor group;
and (3) precise compensation: and the capacitor group for single switching is adopted to carry out single-phase accurate compensation on the compensation capacitor required by each phase.
2. The universal compensation method for power factor of adaptive factory according to claim 1, wherein the rough compensation is performed by: the three capacitors are connected into a group to form a triangle and are connected into the three-phase circuit in parallel.
3. The universal compensation method for power factor of adaptive factory according to claim 1, wherein the precise compensation is performed by: each phase is respectively provided with a plurality of groups of parallel capacitors with different sizes, and the parallel capacitors with corresponding sizes are switched into the corresponding phases according to the sizes of the compensation capacitors required by each phase.
4. An adaptive universal power factor compensator for factory use, the compensator comprising:
the acquisition circuit: collecting voltage and current of a three-phase circuit;
the control circuit: calculating power factors of all phases in the three-phase circuit, and controlling the switching of the capacitor bank to perform power factor compensation control;
the compensation circuit: the three-phase single-circuit capacitor bank comprises an integral switching capacitor bank and an independent switching capacitor bank, and is used for performing rough compensation and accurate compensation of a three-phase single circuit respectively.
5. The adaptive universal factory power factor compensator according to claim 4, wherein the acquisition circuit comprises:
a step-down collector: the voltage reduction acquisition device is used for carrying out voltage reduction acquisition on each phase voltage and comprises a voltage divider and a voltage follower which are connected in sequence;
a current collector: the current transformer, the conversion resistor, the operational amplifier and the voltage follower are sequentially connected;
a dead time measurement circuit: for measuring the time of the current lag voltage of each phase.
6. The adaptive universal power factor compensator according to claim 5, wherein the lag time measuring circuit comprises a first zero-crossing comparator, a second zero-crossing comparator and an XOR gate, the input terminal of the first zero-crossing comparator is grounded with a positive voltage waveform, the input terminal of the first zero-crossing comparator is grounded with a negative voltage, the input terminal of the second zero-crossing comparator is grounded with a negative voltage, the output terminals of the first zero-crossing comparator and the second zero-crossing comparator are connected to the input terminal of the XOR gate, and the high-level time of the output terminal of the XOR gate is the lag time of the voltage waveform.
7. The adaptive universal factory power factor compensator according to claim 6, wherein the control circuit:
a phase difference calculation module: calculating the phase difference between the voltage and the current according to the time of the lagging voltage waveform of the current waveform;
the compensation capacitance calculation module: calculating and compensating the capacitance value of each phase compensation capacitor according to the phase difference;
a coarse compensation control module: the three-phase circuit is roughly compensated by adopting an integral switching capacitor set during primary compensation;
the accurate compensation control module: and the compensation capacitor group is used for carrying out single-phase accurate compensation on compensation capacitors required by each phase by adopting a capacitor group for single switching after the first compensation.
8. The adaptive universal power factor compensator according to claim 7, wherein the control circuit is configured to perform compensation control with a single chip microcomputer as a core.
9. The adaptive factory power factor universal compensation device according to claim 4, wherein the capacitor bank for integral switching comprises: the three capacitors are connected into a group to form a triangle and are connected into the three-phase circuit in parallel.
10. The adaptive universal power factor compensator according to claim 4, wherein the capacitor bank for individual switching specifically comprises: each phase is provided with a plurality of groups of parallel capacitors with different sizes.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102074963A (en) * | 2011-01-17 | 2011-05-25 | 北京清电华力电气自动化科技有限公司 | Intelligent reactive compensation comprehensive control device |
| CN103606933A (en) * | 2013-11-14 | 2014-02-26 | 天津市沃德电力设备有限公司 | Reactive capacitor compensation cabinet |
| CN204144959U (en) * | 2014-11-18 | 2015-02-04 | 哈尔滨理工大学 | The combined compensation system of the electric capacity of loosely coupled transformer |
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- 2021-06-23 CN CN202110698462.5A patent/CN113541155A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102074963A (en) * | 2011-01-17 | 2011-05-25 | 北京清电华力电气自动化科技有限公司 | Intelligent reactive compensation comprehensive control device |
| CN103606933A (en) * | 2013-11-14 | 2014-02-26 | 天津市沃德电力设备有限公司 | Reactive capacitor compensation cabinet |
| CN204144959U (en) * | 2014-11-18 | 2015-02-04 | 哈尔滨理工大学 | The combined compensation system of the electric capacity of loosely coupled transformer |
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Application publication date: 20211022 |