CN209823429U - Three-phase unbalance compensation device - Google Patents
Three-phase unbalance compensation device Download PDFInfo
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- CN209823429U CN209823429U CN201821169494.6U CN201821169494U CN209823429U CN 209823429 U CN209823429 U CN 209823429U CN 201821169494 U CN201821169494 U CN 201821169494U CN 209823429 U CN209823429 U CN 209823429U
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- 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
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- 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
Abstract
The utility model provides a three-phase unbalance compensation device, which comprises a high-precision current sensor, a control system, an IGBT driving unit and a three-phase full-bridge unit which are connected in sequence; the high-precision current sensor is used for monitoring the load current condition in the power grid system in real time; the control system is used for monitoring the current/voltage information of the power grid system, carrying out processing analysis and calculating the compensation current value required by each phase when the balance state is achieved; the IGBT driving unit is used for receiving the pulse width modulation wave sent by the control signal and driving the IGBT unit in a time-sharing manner; and the three-phase full-bridge unit is used for outputting alternating current compensation current during high-frequency conversion. The three-phase unbalance compensation device has the advantages of short response time, no generation of harmonic waves, no secondary power grid pollution, bidirectional split-phase voltage compensation, improvement of voltage quality and capability of reaching the IP44 protection level.
Description
Technical Field
The utility model belongs to among the electric power system, concretely relates to unbalanced three phase compensation arrangement.
Background
In a station, a town, a bridge head and other distribution areas, the three-phase unbalanced load condition of lines is serious, serious influence is caused to residents and industrial electricity, and great potential safety hazards (large transformer noise, serious heating, abnormal sound and the like) exist.
As the user side of the 400V low-voltage distribution system is almost all single-phase load and the electricity consumption has non-timeliness, the distribution transformer system is easy to have the problem of three-phase imbalance, and the imbalance degree is seriously out of standard. The 400V low-voltage distribution system has long power supply radius, and the voltage of a user side is easy to exceed the limit value due to the influence of three-phase unbalanced load and high and low power consumption time periods. The power distribution system widely uses grouping switching capacitors, has compensation steps and poor compensation effect (excessive compensation or insufficient compensation is easy to occur). The distribution transformer has serious overload, causes insufficient output, serious heating, large noise, reduces the service life of the distribution transformer, and even burns out the distribution transformer.
SUMMERY OF THE UTILITY MODEL
To the problem that prior art exists, the utility model provides an unbalanced three phase compensation arrangement. The method has the advantages of short response time, no generation of harmonic wave, no secondary power grid pollution, bidirectional split-phase voltage compensation, voltage quality improvement and capability of reaching the IP44 protection level.
The utility model aims at adopting the following technical scheme to realize:
a three-phase unbalance compensation device is characterized by comprising a high-precision current sensor, a control system, an IGBT driving unit and a three-phase full-bridge unit which are sequentially connected; the high-precision current sensor monitors the load current condition in the power grid system in real time and transmits the load current of the power grid system to the control system in real time for the control system to calculate and make decisions; the control system is used for monitoring current/voltage information of the power grid system, processing and analyzing the current/voltage information, calculating compensation current values required by all phases when the current/voltage information reaches a balanced state, and then sending control signals to the IGBT driver to drive the IGBT to carry out high-frequency on-off and conversion so that the three-phase full-bridge unit converts and outputs current values required by the load of the power grid system; the IGBT driving unit is used for receiving the pulse width modulation wave sent by the control signal, driving the IGBT unit in a time-sharing manner, simultaneously monitoring the state of the IGBT in real time and feeding back the state information to the control system; the three-phase full-bridge unit comprises a three-phase full bridge consisting of Insulated Gate Bipolar Transistors (IGBT) and is used for outputting alternating current compensation current during high-frequency conversion and performing dynamic current transfer and compensation during three-phase unbalance. The three-phase full-bridge unit comprises a three-phase full bridge consisting of six IGBTs, wherein each two IGBTs are connected in series to form a bridge arm, and three bridge arms are formed in total and respectively correspond to the three-phase system. The IGBT driving unit comprises three subunits, and each IGBT driving subunit drives two IGBTs on a corresponding bridge arm respectively.
The control system is responsible for data acquisition, calculation, judgment, control and sending of the PWM wave of the whole device.
The three-phase full-bridge unit also comprises a high-frequency filtering energy inductor which is provided with three groups of phases which are respectively connected in series in a three-phase loop, so that the functions of smoothing and setting the output current of the three-phase full-bridge unit to be standard sinusoidal current and filtering higher harmonic current are realized.
The three-phase four-wire system neutral point voltage stabilizing circuit further comprises a direct current supporting capacitor which is used for connecting two groups of capacitors in series, and a voltage supporting function is provided when three-phase full-bridge power conversion is realized, and meanwhile, a three-phase four-wire system neutral point is provided.
The device also comprises an alternating current breaker which is a protection device, realizes the mechanical contact and isolation functions of the device and a power grid system, has the thermomagnetic tripping function, can rapidly trip when long-time overload or short circuit occurs, and realizes the separation of the device and the power grid.
The system current information is monitored in real time through an external Current Transformer (CT), and the system current information is sent to the control system.
The control system judges whether the power grid system is in an unbalanced state or not through calculation and comparison, if the power grid system is judged to be in the unbalanced state, the current value required to be compensated for each phase when the power grid system reaches the balanced state is calculated again, finally, a control signal is sent to the IGBT driver to drive the IGBT to be switched on and off at high frequency, conversion is achieved, unbalanced current is transferred from a phase with high current to a phase with low current, energy balance redistribution is achieved, finally, a three-phase balanced state is achieved, and finally, a three-phase load compensation function is achieved.
The three-phase unbalance compensation device is used for sampling, filtering and calculating the voltage state information of the power distribution network in real time, and then transmitting the voltage information of the power distribution network to the control system.
The control system firstly judges whether the voltage of a compensation point exceeds a set value, and when the voltage exceeds a voltage regulation upper limit Umax, the three-phase unbalance compensation device outputs inductive current to the power distribution network system by driving a three-phase full-bridge conversion unit consisting of IGBTs, so that the voltage of the power distribution network system is reduced; when the voltage is lower than the lower voltage regulation limit Umin, the three-phase unbalance compensation device outputs capacitive current to the power distribution network system by driving a three-phase full-bridge conversion unit consisting of IGBTs, so that the voltage is increased.
The method is characterized in that the voltage and current phases of the power grid are monitored in real time through an external Current Transformer (CT) and an internal voltage sensor, and the electric energy state information of the power distribution network is sent to a control system.
The reactive power content of the power distribution network is calculated and analyzed at a high speed through a control system, then the control of sending the reactive power to the power distribution network system is realized by controlling the phase angle of the output current and the voltage of the power distribution network, finally the adjustment of the magnitude of the reactive power is realized by controlling the duty ratio of a pulse width modulation signal sent by the control system, and a control signal is sent to an IGBT driving unit to drive an IGBT unit so that an inverter generates reactive compensation current meeting the requirement, thereby realizing the generation of the reactive compensation current meeting the actual requirement of the power distribution network by the device.
The three-phase unbalance compensation device is arranged on the low-voltage side of a distribution transformer of a distribution area, namely between a power grid transformer and a user load.
Compared with the prior art, the beneficial effects of the utility model are that:
1. powerful: and the three-phase unbalanced load dynamic real-time compensation function.
2. Four-quadrant full-time-domain reactive compensation: -1 ~ 1 reactive dynamic full time domain compensation function.
3. A voltage support function; capacitive and inductive reactive compensation functions.
4. The electric energy quality treatment effect is obvious: distributed dynamic compensation in place.
5. Remote data transmission functions are supported.
6. Excellent compensation effect: compensating in real time, wherein the response time is less than 15 ms; the TUC is an active compensation device, a current source device is formed by adopting a latest generation of power electronic devices IGBT, so that the resonance phenomenon caused by traditional capacitance components is avoided in the mechanism, and the TUC is more stable and safer; no harmonic wave is generated, and no secondary power grid pollution is caused; and bidirectional split-phase voltage compensation is performed, so that the voltage quality is improved.
7. Full accuse type equipment, non-maintaining, the cost of using manpower sparingly: the TUC adopts an advanced power electronic technology and a high-speed data processing technology, automatically detects the change of each phase current in a power grid system, calculates and sends out required compensating current in real time so as to enable the power grid to quickly reach a balanced state; the whole process is automatically completed by the equipment without manual operation, and the labor cost consumed by operating the traditional compensation equipment is greatly saved.
8. Multiple protection, adaptation various adverse circumstances: the inner core device of the TUC has various protection functions: overvoltage protection, undervoltage protection, short-circuit protection, etc.; the cabinet body of TUC possesses the protect function: low-voltage lightning protection and leakage protection; and IP protection grade: IP 44.
Drawings
Fig. 1 is a schematic view of an installation of a three-phase unbalance compensation apparatus.
Fig. 2 is a schematic diagram of the three-phase unbalanced load compensation principle and structure.
Fig. 3 is a three-phase voltage support schematic.
Fig. 4A is a capacitive reactive compensation vector diagram.
FIG. 4B is an inductive reactive compensation vector diagram
Detailed Description
The following describes the present invention in further detail with reference to the accompanying drawings.
As shown in fig. 1, the three-phase unbalance compensation device is installed on the low-voltage side of the distribution transformer in the distribution area, i.e., between the grid transformer and the user load.
As shown in fig. 2, the structure of the three-phase unbalanced load compensation device is schematically shown, and the three-phase unbalanced load compensation device mainly includes: the device comprises a high-precision current sensor (7), a control system (3), an IGBT driving unit (2) and a three-phase full-bridge unit (1) which are sequentially connected: in addition, the high-precision current sensor also comprises a high-frequency filter inductor (4), a direct-current supporting capacitor (5) and an alternating-current circuit breaker (6), wherein one end of a high-precision current sensor (7) is connected in series with a power grid system, and the other end inputs a signal to the control system (3) to provide power grid power quality state information for the control system; the control system (3) is directly connected with the IGBT driving unit (2), and the control system can send a driving instruction to the IGBT driving unit through internal high-speed calculation according to the power quality condition of the power grid transmitted back by the current sensor; the IGBT driving unit (2) is directly connected with all IGBTs in the three-phase full-bridge unit (1) to directly drive the IGBTs in the three-phase full-bridge unit to be switched on and off; the high-frequency filter inductor is directly connected with three IGBT bridge arms of the three-phase full-bridge unit to filter high-frequency harmonic components output by the three-phase full-bridge unit; the direct current support capacitor (5) is provided with two ends which are respectively a positive pole and a negative pole, wherein the positive pole is connected with the upper bridge arm of the three-phase full-bridge unit, and the negative pole is connected with the lower bridge arm of the three-phase full-bridge unit, so that a direct current support function is provided for the three-phase full-bridge unit; the alternating current circuit breaker (6) is provided with two ends, one end of the alternating current circuit breaker is connected with the high-frequency filter inductor, and the other end of the alternating current circuit breaker is connected with the power distribution network.
The three-phase full-bridge unit (1) comprises a three-phase full bridge consisting of six IGBTs, wherein each two IGBTs are connected in series to form a bridge arm, and the three bridge arms are formed to correspond to a three-phase system respectively and used for outputting alternating current compensation current during high-frequency conversion and performing dynamic current transfer and compensation during three-phase unbalance. The six IGBTs are respectively installed and fixed on the radiator.
And the IGBT driving unit (2) comprises three subunits, each IGBT driving subunit respectively drives two IGBTs corresponding to one bridge arm, and is used for receiving a pulse width modulation wave sent by a control signal, driving the IGBT units at a high speed in a time-sharing manner, simultaneously monitoring the states of the IGBTs in real time and feeding the state information back to the control system. The IGBT driving unit has IGBT overheating protection, IGBT short-circuit protection and IGBT overvoltage protection functions.
And the control system (3) is used for monitoring the current/voltage information of the power grid system, processing and analyzing the current/voltage information, calculating the compensation current value required by each phase when the current/voltage information reaches a balanced state, and then sending a control signal to the IGBT driver to drive the IGBT to carry out high-frequency on-off and conversion so that the three-phase full-bridge unit converts and outputs the current value required by the load of the power grid system.
The high-precision current sensor (7) monitors the load current condition in the power grid system in real time for the control system (3), and transmits the load current of the power grid system to the control system in real time for the control system to calculate and make decisions.
The high-frequency filtering energy inductor (4) is provided with three groups of phases which are respectively connected in series in a three-phase loop, so that the functions of smoothing and setting the output current of the three-phase full-bridge unit as a standard sinusoidal current and filtering higher harmonic current are realized.
And the direct current supporting capacitor (5) is used for connecting the two groups of capacitors in series, so that when the three-phase full-bridge power conversion is realized, the voltage supporting function is realized, and a three-phase four-wire system neutral point is provided.
The alternating current circuit breaker (6) achieves mechanical contact and isolation functions of the device and a power grid system, has a thermomagnetic tripping function, can rapidly trip when overload or short circuit occurs for a long time, achieves separation of the device from the power grid, protects the device, and reduces influence on the power grid.
Fig. 2 also illustrates the first embodiment. The three-phase unbalance compensation device (TUC-XXX-4-4L) is installed between a three-phase four-wire system power grid and an unbalance load. The power grid load is monitored in real time through an external Current Transformer (CT) (not shown), and system load information is sent to a control system (3) of a three-phase unbalance compensation device (TUC-XXX-4-4L). The control system judges whether the power grid system is in an unbalanced state or not through calculation and comparison, if the power grid system is judged to be in the unbalanced state, the current value required to be compensated for each phase when the power grid system reaches the balanced state is calculated again, finally, a control signal is sent to the IGBT driver to drive the IGBT to be switched on and off at high frequency, conversion is achieved, unbalanced current is transferred from a phase with high current to a phase with low current, energy balance redistribution is achieved, finally, a three-phase balanced state is achieved, and finally, a three-phase load compensation function is achieved.
As shown in fig. 3, a second embodiment of a voltage support is illustrated. The three-phase unbalance compensation device (TUC-XXX-4-4L) is installed between a three-phase four-wire system power grid and an unbalance load. The voltage state information of the power distribution network is sampled, filtered and calculated in real time through the internal voltage sensor of the three-phase unbalance compensation device, and then the voltage information of the power distribution network is transmitted to the control system. The control system firstly judges whether the voltage of a compensation point exceeds a set value, and when the voltage exceeds a voltage regulation upper limit Umax, the three-phase unbalance compensation device outputs inductive current to the power distribution network system by driving a three-phase full-bridge conversion unit consisting of IGBTs, so that the voltage of the power distribution network system is reduced; when the voltage is lower than the lower voltage regulation limit Umin, the three-phase unbalance compensation device outputs capacitive current to the power distribution network system by driving a three-phase full-bridge conversion unit consisting of IGBTs, so that the voltage is increased. Through the control mode, the function of dynamic compensation of the power distribution network system power grid provided with the device can be realized, so that each phase voltage of the power distribution network system is stabilized in a normal range.
As shown in fig. 4A-4B, a third embodiment of reactive power replenishment is illustrated. The method comprises the steps of monitoring the voltage and current phases of a power grid in real time through an external Current Transformer (CT) and an internal voltage sensor, and sending the electric energy state information of the power distribution network to a control system. The reactive power content of the power distribution network is calculated and analyzed at a high speed through a control system, then the control of sending reactive power to the power distribution network system is realized by controlling the phase angle of output current and power grid voltage, finally the adjustment of the magnitude of the reactive power is realized by controlling the duty ratio of a pulse width modulation signal sent by the control system, and a control signal is sent to an IGBT driving unit to drive an IGBT unit so that an inverter generates reactive compensation current meeting the requirement, so that the device generates reactive compensation current meeting the actual requirement of the power distribution network, and finally the dynamic reactive compensation function is realized.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the same, and although the utility model is described in detail with reference to the above embodiments, those skilled in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which should be construed to be within the scope of the claims.
Claims (12)
1. A three-phase unbalance compensation device is characterized by comprising a high-precision current sensor, a control system, an IGBT driving unit and a three-phase full-bridge unit which are sequentially connected;
the high-precision current sensor monitors the load current condition in the power grid system in real time and transmits the load current of the power grid system to the control system in real time for the control system to calculate and make decisions;
the control system is used for monitoring current/voltage information of the power grid system, processing and analyzing the current/voltage information, calculating compensation current values required by all phases when the current/voltage information reaches a balanced state, and then sending control signals to the IGBT driver to drive the IGBT to carry out high-frequency on-off and conversion so that the three-phase full-bridge unit converts and outputs current values required by the load of the power grid system;
the IGBT driving unit is used for receiving the pulse width modulation wave sent by the control signal, driving the IGBT unit in a time-sharing manner, simultaneously monitoring the state of the IGBT in real time and feeding back the state information to the control system;
the three-phase full-bridge unit comprises a three-phase full bridge consisting of Insulated Gate Bipolar Transistors (IGBT) and is used for outputting alternating current compensation current during high-frequency conversion and performing dynamic current transfer and compensation during three-phase unbalance.
2. The three-phase imbalance compensation device of claim 1, wherein the three-phase full-bridge unit comprises a three-phase full-bridge consisting of six IGBTs, wherein each two IGBTs are connected in series to form a bridge arm, and the three bridge arms are formed to correspond to the three-phase system.
3. The apparatus according to claim 1, wherein the IGBT driving unit comprises three sub-units, and each of the IGBT driving sub-units drives two IGBTs of a corresponding arm, respectively.
4. A three-phase unbalance compensation apparatus according to claim 3, wherein the control system is responsible for data acquisition, calculation, judgment, control and transmission of the pulse width modulation wave PWM of the whole apparatus.
5. The apparatus as claimed in claim 1, further comprising a high frequency filtering inductor having three phases connected in series in the three-phase loop respectively, for smoothing and setting the output current of the three-phase full-bridge unit to be a standard sinusoidal current, and filtering out higher harmonic current.
6. The apparatus of claim 5, further comprising a DC support capacitor, wherein the DC support capacitor is connected in series with the two sets of capacitors to provide a voltage support function and a three-phase four-wire neutral point when the three-phase full-bridge power conversion is performed.
7. The apparatus of claim 6, further comprising an ac circuit breaker, wherein the ac circuit breaker is a protection device for achieving mechanical contact and isolation between the apparatus and the grid system, and has a thermo-magnetic trip function for rapidly tripping to achieve separation of the apparatus from the grid when a long overload or short circuit occurs.
8. A three-phase unbalance compensation device according to any of claims 1-7, characterized in that the network voltage and current phase are monitored in real time by means of an external Current Transformer (CT) and an internal voltage sensor, and the network power status information is transmitted to the control system.
9. The three-phase imbalance compensation device of claim 8, wherein the control system calculates and compares whether the current cut-off network system is in an unbalanced state, if the power distribution network system is judged to be in the unbalanced state, the current value required to be compensated for each phase when the power distribution network system reaches the balanced state is calculated again, and finally, the control signal is sent to the IGBT driver to drive the IGBT to be switched on and off at high frequency, so that the conversion is realized, the unbalanced current is transferred from the phase with high current to the phase with low current, the energy balance is realized, the three-phase imbalance state is finally reached, and the function of three-phase load compensation is finally realized.
10. The three-phase unbalance compensation device according to claim 8, wherein the control system first determines whether the voltage at the compensation point exceeds a set value, and when the voltage exceeds the upper regulation limit Umax, the three-phase unbalance compensation device outputs an inductive current to the distribution network system by driving a three-phase full-bridge conversion unit composed of IGBTs, thereby reducing the voltage of the distribution network system; when the voltage is lower than the lower voltage regulation limit Umin, the three-phase unbalance compensation device outputs capacitive current to the power distribution network system by driving a three-phase full-bridge conversion unit consisting of IGBTs, so that the voltage is increased.
11. The three-phase imbalance compensation device according to claim 8, wherein the reactive power content of the power distribution network is calculated and analyzed at a high speed through the control system, then the control of the reactive power sent to the power distribution network system is realized by controlling the phase angle of the output current and the voltage of the power grid, finally the adjustment of the magnitude of the reactive power is realized by controlling the duty ratio of the pulse width modulation signal sent by the control system, and a control signal is sent to the IGBT driving unit to drive the IGBT unit so that the inverter generates the reactive compensation current meeting the requirements, thereby realizing the generation of the reactive compensation current meeting the actual requirements of the power distribution network.
12. A three-phase unbalance compensation device according to any one of claims 1-7, wherein the three-phase unbalance compensation device is installed on the low-voltage side of the distribution transformer of the distribution area, between the grid transformer and the user load.
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| CN201821169494.6U CN209823429U (en) | 2018-07-24 | 2018-07-24 | Three-phase unbalance compensation device |
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| CN201821169494.6U CN209823429U (en) | 2018-07-24 | 2018-07-24 | Three-phase unbalance compensation device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114172174A (en) * | 2021-12-20 | 2022-03-11 | 国网黑龙江省电力有限公司佳木斯供电公司 | Unbalanced three-phase adjusting device for power distribution network |
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2018
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114172174A (en) * | 2021-12-20 | 2022-03-11 | 国网黑龙江省电力有限公司佳木斯供电公司 | Unbalanced three-phase adjusting device for power distribution network |
| CN114172174B (en) * | 2021-12-20 | 2022-06-21 | 国网黑龙江省电力有限公司佳木斯供电公司 | Unbalanced three phase adjusting device for power distribution network |
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