CN110429612B - Zero sequence current compensation method and device - Google Patents

Zero sequence current compensation method and device Download PDF

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Publication number
CN110429612B
CN110429612B CN201910670993.6A CN201910670993A CN110429612B CN 110429612 B CN110429612 B CN 110429612B CN 201910670993 A CN201910670993 A CN 201910670993A CN 110429612 B CN110429612 B CN 110429612B
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zero
sequence current
compensation
transformer
type transformer
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CN110429612A (en
Inventor
范伟强
颛孙旭
程婷婷
李复明
王弋飞
许斐
李在强
张小民
万媛
王育路
李龙
罗海
郑伟
金谨
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Xi'an Xidian Electric Research Institute Co ltd
China XD Electric Co Ltd
Economic and Technological Research Institute of State Grid Shaanxi Electric Power Co Ltd
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Xi'an Xidian Electric Research Institute Co ltd
China XD Electric Co Ltd
Economic and Technological Research Institute of State Grid Shaanxi Electric Power Co Ltd
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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
    • H02J3/1842—Arrangements for adjusting, eliminating or compensating reactive power in networks using shunt compensators with stepless control wherein at least one reactive element is actively controlled by a bridge converter, e.g. active filters
    • 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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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Electrical Variables (AREA)
  • Control Of Eletrric Generators (AREA)

Abstract

The invention provides a zero sequence current compensation method and a zero sequence current compensation device, wherein the method comprises the following steps: obtaining zero sequence current of the Z-shaped transformer; if the zero-sequence current of the Z-shaped transformer is judged and known to be larger than a preset value, determining the compensation zero-sequence current of the Z-shaped transformer and the compensation zero-sequence current of the static var generator according to a zero-sequence current compensation rule; sending a first zero-sequence current compensation instruction to the Z-type transformer, and sending a second zero-sequence current compensation instruction to the static var generator to realize zero-sequence current compensation; the first zero-sequence current compensation instruction carries the compensation zero-sequence current of the Z-type transformer, and the second zero-sequence current compensation instruction carries the compensation zero-sequence current of the static var generator. The device is used for executing the method. The zero sequence current compensation method and the zero sequence current compensation device provided by the embodiment of the invention can effectively prevent the Z-type transformer from overcurrent and simultaneously improve the compensation capacity of the zero sequence current.

Description

Zero sequence current compensation method and device
Technical Field
The invention relates to the technical field of power electronics, in particular to a zero sequence current compensation method and a zero sequence current compensation device.
Background
The electric power is the most widely applied energy form at present, is a precondition for the development of various industries, and with the development of various high and new industries and the promotion of electric power reform, the electric power supply needs to keep up with the ever-increasing power capacity demand and meet the increasingly-high power supply quality requirement.
At present, the power quality problems are mainly reflected in reactive compensation, harmonic suppression and three-phase imbalance. Most users are positioned at the tail end of the power distribution network and are mostly single-phase loads, and three-phase loads are randomly changed and are usually unbalanced, so that three-phase unbalanced current is generated, three-phase voltage is unbalanced, line loss is increased, the safe operation of a public power grid is influenced, and even large-area power failure can be caused; and in severe cases, the problems of user equipment damage, product scrap, data loss and the like can also be caused. For three-phase unbalanced current, the three-phase unbalanced current can be decomposed into positive sequence current, negative sequence current and zero sequence current. At the end of the distribution network, a large amount of zero sequence current is generated due to the distribution of a large amount of single-phase loads, and the zero sequence current is the main cause of three-phase imbalance. In the prior art, a Static Var Generator (SVG) or a Z-type transformer or other devices may be used to perform zero-sequence current compensation. However, the zero-sequence current compensation capability of the SVG is affected by power electronic devices and direct-current side capacitors, and the control algorithm is complex and the cost is high; the zero sequence current compensated by the Z-type transformer depends on the magnitude of the zero sequence current of the load, and when the zero sequence current of the load is overlarge, the Z-type transformer is easy to cause overcurrent and even damage.
Disclosure of Invention
In view of the above problems in the prior art, embodiments of the present invention provide a zero sequence current compensation method and apparatus, which can at least partially solve the problems in the prior art.
In one aspect, the present invention provides a zero sequence current compensation method, including:
obtaining zero sequence current of the Z-shaped transformer;
if the zero-sequence current of the Z-shaped transformer is judged and known to be larger than a preset value, determining the compensation zero-sequence current of the Z-shaped transformer and the compensation zero-sequence current of the static var generator according to a zero-sequence current compensation rule;
sending a first zero-sequence current compensation instruction to the Z-type transformer, and sending a second zero-sequence current compensation instruction to the static var generator to realize zero-sequence current compensation; the first zero-sequence current compensation instruction carries the compensation zero-sequence current of the Z-type transformer, and the second zero-sequence current compensation instruction carries the compensation zero-sequence current of the static var generator.
In another aspect, the present invention provides a zero sequence current compensation apparatus, including:
the acquisition unit is used for acquiring the zero sequence current of the Z-type transformer;
the first judgment unit is used for determining the compensation zero-sequence current of the Z-shaped transformer and the compensation zero-sequence current of the static var generator according to a zero-sequence current compensation rule after judging that the zero-sequence current of the Z-shaped transformer is larger than a preset value;
the transmitting unit is used for transmitting a first zero-sequence current compensation instruction to the Z-type transformer and transmitting a second zero-sequence current compensation instruction to the static var generator so as to realize zero-sequence current compensation; the first zero-sequence current compensation instruction carries the compensation zero-sequence current of the Z-type transformer, and the second zero-sequence current compensation instruction carries the compensation zero-sequence current of the static var generator.
In another aspect, the present invention provides an electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the steps of the zero sequence current compensation method according to any of the above embodiments are implemented.
In yet another aspect, the present invention provides a computer readable storage medium, on which a computer program is stored, which when executed by a processor, implements the steps of the zero sequence current compensation method according to any of the embodiments described above.
According to the zero-sequence current compensation method and device provided by the embodiment of the invention, as the zero-sequence current of the Z-type transformer can be obtained, and after the zero-sequence current of the Z-type transformer is judged and known to be larger than the preset value, the compensation zero-sequence current of the Z-type transformer and the compensation zero-sequence current of the static var generator are determined according to the zero-sequence current compensation rule, and then the first zero-sequence current compensation instruction is sent to the Z-type transformer and the second zero-sequence current compensation instruction is sent to the static var generator to realize zero-sequence current compensation, so that the zero-sequence current compensation of the Z-type transformer and the static var generator is simultaneously carried out, the Z-type transformer is effectively prevented from overcurrent, and the compensation capacity of the zero-sequence current is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts. In the drawings:
fig. 1 is a schematic structural diagram of a three-phase imbalance compensation apparatus according to an embodiment of the present invention.
Fig. 2 is a schematic flow chart of a zero sequence current compensation method according to an embodiment of the present invention.
Fig. 3 is a schematic flow chart of a zero sequence current compensation method according to another embodiment of the present invention.
Fig. 4 is a schematic structural diagram of a zero-sequence current compensation apparatus according to an embodiment of the present invention.
Fig. 5 is a schematic structural diagram of a zero-sequence current compensation device according to another embodiment of the present invention.
Fig. 6 is a schematic physical structure diagram of an electronic device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.
Fig. 1 is a schematic structural diagram of a three-phase imbalance compensation device according to an embodiment of the present invention, as shown in fig. 1, the three-phase imbalance compensation device according to the embodiment of the present invention includes a static var generator 1, a Z-type transformer 2, and a detection unit (not shown in the figure), an ac side of SVG1 is connected in parallel to a power grid (phase a, phase B, and phase C) through a connection inductor, a neutral line (N) of the power grid is connected to a midpoint of a dc side of SVG1, the Z-type transformer 2 is directly connected in parallel to the power grid, and the detection unit can detect a zero sequence current flowing through the Z-type transformer 2, a three-phase current and a zero sequence current flowing through SVG1, and a zero sequence current flowing through a load, and then send a related zero sequence current compensation command to SVG1 and the Z-type transformer 2 to perform zero sequence current compensation by using the zero sequence current compensation method provided by the embodiment of the present invention. The detection unit may include a current transformer for current detection and a controller for executing the zero-sequence current compensation method provided by the embodiment of the present invention, where the controller is connected to the current transformer, and the controller includes but is not limited to a PID controller. SVG1 is a continuous reactive power compensation device whose three-phase four-wire device can implement the compensation of unbalanced reactive power while compensating negative sequence current, thereby implementing the function of unbalanced compensation. The Z-type transformer 2 can realize compensation of a large amount of zero sequence current. It can be understood that the grid is connected to a load of a single-phase load, which causes a voltage imbalance of the grid.
Fig. 2 is a schematic flow chart of a zero sequence current compensation method according to an embodiment of the present invention, and as shown in fig. 2, the zero sequence current compensation method according to the embodiment of the present invention includes:
s201, obtaining zero sequence current of the Z-shaped transformer;
specifically, the detection unit of the three-phase imbalance compensation device may directly detect and obtain the zero sequence current flowing through the Z-type transformer through the current transformer, so as to obtain the zero sequence current of the Z-type transformer. Or, the detection unit can detect the zero sequence current flowing through the load to obtain the zero sequence current on the load side, and simultaneously detect the zero sequence current flowing through the SVG to obtain the zero sequence current of the SVG, and then subtract the zero sequence current of the SVG from the zero sequence current on the load side to obtain the zero sequence current of the Z-type transformer.
S202, if the zero-sequence current of the Z-shaped transformer is judged and known to be larger than a preset value, determining the compensation zero-sequence current of the Z-shaped transformer and the compensation zero-sequence current of the static var generator according to a zero-sequence current compensation rule;
specifically, after obtaining the zero sequence current of the Z-type transformer, the detecting unit compares the zero sequence current of the Z-type transformer with a preset value, and if the zero sequence current of the Z-type transformer is greater than the preset value, it indicates that the compensation of the zero sequence current needs to be performed by using the Z-type transformer and the SVG together, and then the detecting unit determines the compensation zero sequence current of the Z-type transformer and the compensation zero sequence current of the SVG according to the zero sequence current compensation rule. And the compensation zero-sequence current of the Z-type transformer and the compensation zero-sequence current of the SVG are used for compensating the zero-sequence current generated when the three phases of the power grid are unbalanced, so that the three-phase voltage balance of the power grid is ensured. The preset value can be set to be k times of rated zero-sequence current of the Z-type transformer, k is greater than 0.5 and smaller than 1.2, and the value of k is set according to practical experience, which is not limited in the embodiment of the invention; the zero sequence current compensation rule is preset.
For example, the zero sequence current compensation rule includes: the compensation zero-sequence current of the Z-shaped transformer is the preset value, and the compensation zero-sequence current of the static var generator is the difference value of the zero-sequence current of the Z-shaped transformer minus the rated zero-sequence current of the Z-shaped transformer. On one hand, the compensation zero sequence current of the Z-shaped transformer does not exceed the rated zero sequence current of the Z-shaped transformer, so that the Z-shaped transformer can be effectively prevented from overcurrent; on the other hand, the SVG is used for compensating the zero sequence current exceeding the preset value, so that the compensation capacity of the zero sequence current can be improved.
S203, sending a first zero-sequence current compensation instruction to the Z-type transformer, and sending a second zero-sequence current compensation instruction to the static var generator to realize zero-sequence current compensation; the first zero-sequence current compensation instruction carries the compensation zero-sequence current of the Z-type transformer, and the second zero-sequence current compensation instruction carries the compensation zero-sequence current of the static var generator.
Specifically, after obtaining the compensation zero-sequence current of the Z-type transformer and the compensation zero-sequence current of the SVG, the detecting unit sends a first zero-sequence current compensation instruction to the Z-type transformer, where the first zero-sequence current compensation instruction carries the compensation zero-sequence current of the Z-type transformer, and after receiving the first zero-sequence current compensation instruction, the Z-type transformer compensates the zero-sequence current of the power grid according to the compensation zero-sequence current of the Z-type transformer. And the detection unit sends a second zero-sequence current compensation instruction to the SVG, the second zero-sequence current compensation instruction carries the compensation zero-sequence current of the SVG, and the SVG compensates the zero-sequence current of the power grid according to the compensation zero-sequence current of the SVG after receiving the second zero-sequence current compensation instruction. Namely, the Z-type transformer and the SVG compensate the zero sequence current of the power grid at the same time, so as to achieve the purpose of balancing the three-phase voltage of the power grid.
According to the zero sequence current compensation method provided by the embodiment of the invention, the zero sequence current of the Z-type transformer can be obtained, after the zero sequence current of the Z-type transformer is judged and known to be larger than the preset value, the compensation zero sequence current of the Z-type transformer and the compensation zero sequence current of the static var generator are determined according to the zero sequence current compensation rule, and then the first zero sequence current compensation instruction is sent to the Z-type transformer and the second zero sequence current compensation instruction is sent to the static var generator to realize zero sequence current compensation, so that the zero sequence current compensation of the Z-type transformer and the static var generator is simultaneously carried out, and the compensation capacity of the zero sequence current is improved. In addition, the Z-type transformer can be prevented from overflowing while zero-sequence current compensation is carried out by the Z-type transformer at the maximum efficiency.
On the basis of the foregoing embodiments, further, the zero-sequence current compensation rule includes:
the compensation zero-sequence current of the Z-shaped transformer is the preset value, and the compensation zero-sequence current of the static var generator is the difference value of the zero-sequence current of the Z-shaped transformer minus the compensation zero-sequence current of the Z-shaped transformer.
Specifically, the principle of the zero sequence current compensation rule is to preferentially use the Z-type transformer to compensate the zero sequence current, and the zero sequence current beyond the compensation range of the Z-type transformer is compensated by using SVG. Therefore, the compensating zero-sequence current of the Z-type transformer is set to be the preset value, and the zero-sequence current exceeding the preset value is compensated by the SVG, namely the compensating zero-sequence current of the SVG is the difference value of the zero-sequence current of the Z-type transformer minus the compensating zero-sequence current of the Z-type transformer.
For example, the preset value p ═ kIN0K is more than 0.5 and less than 1.2, for example, k is 0.9, the value of k can be set according to the application and the characteristics of the Z-type transformer, IN0The rated zero sequence current of the Z-type transformer is the zero sequence current I flowing through the Z-type transformeri0>When p is measured, the zero sequence compensation current of the Z-type transformer is p, SVG has a zero-sequence compensation current of Ii0-p。
On the basis of the foregoing embodiments, further, the zero-sequence current compensation rule includes:
the compensation zero-sequence current of the Z-shaped transformer is the preset value, and the compensation zero-sequence current of the static var generator is obtained by subtracting the compensation zero-sequence current of the Z-shaped transformer from the zero-sequence current of the load side; wherein the load side zero sequence current is obtained in advance.
Specifically, the principle of the zero sequence current compensation rule is to preferentially use the Z-type transformer to compensate the zero sequence current, and the zero sequence current beyond the compensation range of the Z-type transformer is compensated by using SVG. Therefore, the compensating zero-sequence current of the Z-type transformer is set to be the preset value, and the zero-sequence current exceeding the preset value is compensated by the SVG. The zero sequence current at the load side can be acquired, and the zero sequence current at the load side subtracts the compensation zero sequence current of the Z-shaped transformer to obtain the compensation zero sequence current of the static var generator. Wherein the load side zero sequence current is obtained in advance.
For example, the preset value p ═ kIN0K is more than 0.5 and less than 1.2, for example, k is 0.9, the value of k can be set according to the application and the characteristics of the Z-type transformer, IN0Acquiring the rated zero-sequence current of the Z-type transformer to obtain the zero-sequence current I on the load sideL0When the zero sequence current I flows through the Z-type transformeri0>When p is needed, the zero-sequence compensation current of the Z-type transformer is p, and the zero-sequence compensation current of the SVG is IL0-p. Wherein, when carrying out zero sequence current compensation through SVG, can gather the actual value I who obtains the compensation zero sequence current of SVGsIf I issIs not equal to IL0P, then can be paired with IsMaking an adjustment tosIs equal to IL0-p。
Fig. 3 is a schematic flow chart of a zero sequence current compensation method according to another embodiment of the present invention, and on the basis of the foregoing embodiments, further, the zero sequence current compensation method according to the embodiment of the present invention further includes:
and S204, if the zero-sequence current of the Z-shaped transformer is judged to be smaller than or equal to the preset value, determining to use the Z-shaped transformer to independently perform zero-sequence current compensation.
Specifically, after obtaining the zero-sequence current of the Z-type transformer, the detecting unit compares the zero-sequence current of the Z-type transformer with the preset value, and if the zero-sequence current of the Z-type transformer is smaller than or equal to the preset value, it indicates that the compensation of the zero-sequence current is within the bearing range of the Z-type transformer, the Z-type transformer may be used to perform zero-sequence current compensation alone, the detecting unit may send a zero-sequence current compensation command to the Z-type transformer alone, so that the Z-type transformer performs zero-sequence current compensation, the zero-sequence current compensation command carries the zero-sequence current of the Z-type transformer, and the zero-sequence current to be compensated of the Z-type transformer is equal to the zero-sequence current of the Z-type transformer. Because the Z-type transformer is preferentially used for compensating the zero-sequence current, the zero-sequence current of the SVG compensation can be reduced, and the compensation capacity of the SVG is improved.
Understandably, because the SVG has a function of compensating three-phase negative sequence active current, three-phase negative sequence reactive current and three-phase positive sequence reactive current, the SVG can be used for compensating the three-phase negative sequence active current, the three-phase negative sequence reactive current and the three-phase positive sequence reactive current no matter the zero sequence current of the Z-type transformer is larger than the preset value or the zero sequence current of the Z-type transformer is smaller than or equal to the preset value.
Fig. 4 is a schematic structural diagram of the zero sequence current compensation apparatus according to an embodiment of the present invention, and as shown in fig. 4, the zero sequence current compensation apparatus according to the embodiment of the present invention includes an obtaining unit 401, a first determining unit 402, and a sending unit 403, where:
the obtaining unit 401 is configured to obtain a zero sequence current of the Z-type transformer; the first judging unit 402 is configured to determine a compensation zero-sequence current of the Z-type transformer and a compensation zero-sequence current of the static var generator according to a zero-sequence current compensation rule after judging that the zero-sequence current of the Z-type transformer is greater than a preset value; the sending unit 403 is configured to send a first zero-sequence current compensation instruction to the Z-type transformer, and send a second zero-sequence current compensation instruction to the static var generator to implement zero-sequence current compensation; the first zero-sequence current compensation instruction carries the compensation zero-sequence current of the Z-type transformer, and the second zero-sequence current compensation instruction carries the compensation zero-sequence current of the static var generator.
Specifically, the obtaining unit 401 may obtain the zero sequence current flowing through the Z-type transformer by directly detecting through a current transformer, so as to obtain the zero sequence current of the Z-type transformer. Or, the obtaining unit 401 may detect the zero-sequence current flowing through the load to obtain a load-side zero-sequence current, and simultaneously detect the zero-sequence current flowing through the SVG to obtain a zero-sequence current of the SVG, and then subtract the zero-sequence current of the SVG from the load-side zero-sequence current to obtain a zero-sequence current of the Z-type transformer.
After obtaining the zero sequence current of the Z-type transformer, the first determining unit 402 compares the zero sequence current of the Z-type transformer with a preset value, and if the zero sequence current of the Z-type transformer is greater than the preset value, it indicates that the compensation of the zero sequence current needs to be performed by using the Z-type transformer and the SVG together, and then the first determining unit 402 determines the compensation zero sequence current of the Z-type transformer and the compensation zero sequence current of the SVG according to the zero sequence current compensation rule. And the compensation zero-sequence current of the Z-type transformer and the compensation zero-sequence current of the SVG are used for compensating the zero-sequence current generated when the three phases of the power grid are unbalanced, so that the three-phase voltage balance of the power grid is ensured. The preset value can be set to be k times of rated zero-sequence current of the Z-type transformer, k is greater than 0.5 and smaller than 1.2, and the value of k is set according to practical experience, which is not limited in the embodiment of the invention; the zero sequence current compensation rule is preset.
After obtaining the zero-sequence compensation current of the Z-type transformer and the zero-sequence compensation current of the SVG, the sending unit 403 sends a first zero-sequence current compensation instruction to the Z-type transformer, where the first zero-sequence current compensation instruction carries the zero-sequence compensation current of the Z-type transformer, and after receiving the first zero-sequence current compensation instruction, the Z-type transformer compensates the zero-sequence current of the power grid according to the zero-sequence compensation current of the Z-type transformer. And, the sending unit 403 sends a second zero-sequence current compensation instruction to the SVG, where the second zero-sequence current compensation instruction carries the compensation zero-sequence current of the SVG, and the SVG compensates the zero-sequence current of the power grid according to the compensation zero-sequence current of the SVG after receiving the second zero-sequence current compensation instruction. Namely, the Z-type transformer and the SVG compensate the zero sequence current of the power grid at the same time, so as to achieve the purpose of balancing the three-phase voltage of the power grid.
According to the zero sequence current compensation device provided by the embodiment of the invention, the zero sequence current of the Z-shaped transformer can be obtained, after the zero sequence current of the Z-shaped transformer is judged and known to be larger than the preset value, the compensation zero sequence current of the Z-shaped transformer and the compensation zero sequence current of the static var generator are determined according to the zero sequence current compensation rule, and then the first zero sequence current compensation instruction is sent to the Z-shaped transformer and the second zero sequence current compensation instruction is sent to the static var generator to realize zero sequence current compensation, so that the zero sequence current compensation of the Z-shaped transformer and the static var generator is simultaneously carried out, and the compensation capacity of the zero sequence current is improved. In addition, the Z-type transformer can be prevented from overflowing while zero-sequence current compensation is carried out by the Z-type transformer at the maximum efficiency.
On the basis of the above embodiments, further, the zero sequence current compensation rule carries:
the compensation zero-sequence current of the Z-shaped transformer is the preset value, and the compensation zero-sequence current of the static var generator is the difference value of the zero-sequence current of the Z-shaped transformer minus the compensation zero-sequence current of the Z-shaped transformer.
Specifically, the principle of the zero sequence current compensation rule is to preferentially use the Z-type transformer to compensate the zero sequence current, and the zero sequence current beyond the compensation range of the Z-type transformer is compensated by using SVG. Therefore, the compensating zero-sequence current of the Z-type transformer is set to be the preset value, and the zero-sequence current exceeding the preset value is compensated by the SVG, namely the compensating zero-sequence current of the SVG is the difference value of the zero-sequence current of the Z-type transformer minus the compensating zero-sequence current of the Z-type transformer.
On the basis of the foregoing embodiments, further, the zero-sequence current compensation rule includes:
the compensation zero-sequence current of the Z-shaped transformer is the preset value, and the compensation zero-sequence current of the static var generator is obtained by subtracting the compensation zero-sequence current of the Z-shaped transformer from the zero-sequence current of the load side; wherein the load side zero sequence current is obtained in advance.
Specifically, the principle of the zero sequence current compensation rule is to preferentially use the Z-type transformer to compensate the zero sequence current, and the zero sequence current beyond the compensation range of the Z-type transformer is compensated by using SVG. Therefore, the compensating zero-sequence current of the Z-type transformer is set to be the preset value, and the zero-sequence current exceeding the preset value is compensated by the SVG. The zero sequence current at the load side can be acquired, and the zero sequence current at the load side subtracts the compensation zero sequence current of the Z-shaped transformer to obtain the compensation zero sequence current of the static var generator. Wherein the load side zero sequence current is obtained in advance.
Fig. 5 is a schematic structural diagram of a zero sequence current compensation apparatus according to another embodiment of the present invention, as shown in fig. 5, on the basis of the foregoing embodiments, further, the zero sequence current compensation apparatus according to the embodiment of the present invention further includes a second determining unit 404, where:
the second judging unit 404 is configured to determine that zero-sequence current compensation is performed by using the Z-type transformer alone after it is judged and known that the zero-sequence current of the Z-type transformer is less than or equal to the preset value.
Specifically, after obtaining the zero sequence current of the Z-type transformer, the second determining unit 404 compares the zero sequence current of the Z-type transformer with the preset value, and if the zero sequence current of the Z-type transformer is less than or equal to the preset value, it indicates that the compensation of the zero sequence current is within the bearing range of the Z-type transformer, the Z-type transformer may be used to perform zero sequence current compensation alone, the second determining unit 404 may send a zero sequence current compensation command to the Z-type transformer alone, so that the Z-type transformer performs zero sequence current compensation, the zero sequence current compensation command carries the zero sequence current of the Z-type transformer, and the zero sequence current to be compensated of the Z-type transformer is equal to the zero sequence current of the Z-type transformer. Because the Z-type transformer is preferentially used for compensating the zero-sequence current, the zero-sequence current of the SVG compensation can be reduced, and the compensation capacity of the SVG is improved.
Fig. 6 is a schematic physical structure diagram of an electronic device according to an embodiment of the present invention, and as shown in fig. 6, the electronic device may include: a processor (processor)601, a communication Interface (Communications Interface)602, a memory (memory)603 and a communication bus 604, wherein the processor 601, the communication Interface 602 and the memory 603 complete communication with each other through the communication bus 604. The processor 601 may call logic instructions in the memory 603 to perform the following method: obtaining zero sequence current of the Z-shaped transformer; if the zero-sequence current of the Z-shaped transformer is judged and known to be larger than a preset value, determining the compensation zero-sequence current of the Z-shaped transformer and the compensation zero-sequence current of the static var generator according to a zero-sequence current compensation rule; sending a first zero-sequence current compensation instruction to the Z-type transformer, and sending a second zero-sequence current compensation instruction to the static var generator to realize zero-sequence current compensation; the first zero-sequence current compensation instruction carries the compensation zero-sequence current of the Z-type transformer, and the second zero-sequence current compensation instruction carries the compensation zero-sequence current of the static var generator.
In addition, the logic instructions in the memory 603 may be implemented in the form of software functional units and stored in a computer readable storage medium when the logic instructions are sold or used as independent products. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The present embodiment discloses a computer program product comprising a computer program stored on a non-transitory computer readable storage medium, the computer program comprising program instructions which, when executed by a computer, enable the computer to perform the method provided by the above-mentioned method embodiments, for example, comprising: obtaining zero sequence current of the Z-shaped transformer; if the zero-sequence current of the Z-shaped transformer is judged and known to be larger than a preset value, determining the compensation zero-sequence current of the Z-shaped transformer and the compensation zero-sequence current of the static var generator according to a zero-sequence current compensation rule; sending a first zero-sequence current compensation instruction to the Z-type transformer, and sending a second zero-sequence current compensation instruction to the static var generator to realize zero-sequence current compensation; the first zero-sequence current compensation instruction carries the compensation zero-sequence current of the Z-type transformer, and the second zero-sequence current compensation instruction carries the compensation zero-sequence current of the static var generator.
The present embodiment provides a computer-readable storage medium, which stores a computer program, where the computer program causes the computer to execute the method provided by the above method embodiments, for example, the method includes: obtaining zero sequence current of the Z-shaped transformer; if the zero-sequence current of the Z-shaped transformer is judged and known to be larger than a preset value, determining the compensation zero-sequence current of the Z-shaped transformer and the compensation zero-sequence current of the static var generator according to a zero-sequence current compensation rule; sending a first zero-sequence current compensation instruction to the Z-type transformer, and sending a second zero-sequence current compensation instruction to the static var generator to realize zero-sequence current compensation; the first zero-sequence current compensation instruction carries the compensation zero-sequence current of the Z-type transformer, and the second zero-sequence current compensation instruction carries the compensation zero-sequence current of the static var generator.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
In the description herein, reference to the description of the terms "one embodiment," "a particular embodiment," "some embodiments," "for example," "an example," "a particular example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (10)

1. A zero sequence current compensation method, comprising:
obtaining zero sequence current of the Z-shaped transformer;
if the zero-sequence current of the Z-shaped transformer is judged and known to be larger than a preset value, determining the compensation zero-sequence current of the Z-shaped transformer and the compensation zero-sequence current of the static var generator according to a zero-sequence current compensation rule; the compensation zero-sequence current of the Z-type transformer is equal to the preset value;
sending a first zero-sequence current compensation instruction to the Z-type transformer, and sending a second zero-sequence current compensation instruction to the static var generator to realize zero-sequence current compensation; the first zero-sequence current compensation instruction carries the compensation zero-sequence current of the Z-type transformer, and the second zero-sequence current compensation instruction carries the compensation zero-sequence current of the static var generator; the Z-type transformer and the static var generator are connected at the same access point.
2. The method of claim 1, wherein the zero sequence current compensation rule comprises:
the compensation zero-sequence current of the Z-shaped transformer is the preset value, and the compensation zero-sequence current of the static var generator is the difference value of the zero-sequence current of the Z-shaped transformer minus the compensation zero-sequence current of the Z-shaped transformer.
3. The method of claim 1, wherein the zero sequence current compensation rule comprises:
the compensation zero-sequence current of the Z-shaped transformer is the preset value, and the compensation zero-sequence current of the static var generator is obtained by subtracting the compensation zero-sequence current of the Z-shaped transformer from the zero-sequence current of the load side; wherein the load side zero sequence current is obtained in advance.
4. The method of any of claims 1 to 3, further comprising:
and if the zero-sequence current of the Z-shaped transformer is judged to be smaller than or equal to the preset value, determining to use the Z-shaped transformer to carry out zero-sequence current compensation independently.
5. A zero sequence current compensation arrangement, characterized by comprising:
the acquisition unit is used for acquiring the zero sequence current of the Z-type transformer;
the first judgment unit is used for determining the compensation zero-sequence current of the Z-shaped transformer and the compensation zero-sequence current of the static var generator according to a zero-sequence current compensation rule after judging that the zero-sequence current of the Z-shaped transformer is larger than a preset value; the compensation zero-sequence current of the Z-type transformer is equal to the preset value;
the transmitting unit is used for transmitting a first zero-sequence current compensation instruction to the Z-type transformer and transmitting a second zero-sequence current compensation instruction to the static var generator so as to realize zero-sequence current compensation; the first zero-sequence current compensation instruction carries the compensation zero-sequence current of the Z-type transformer, and the second zero-sequence current compensation instruction carries the compensation zero-sequence current of the static var generator; the Z-type transformer and the static var generator are connected at the same access point.
6. The apparatus of claim 5, wherein the zero sequence current compensation rule comprises:
the compensation zero-sequence current of the Z-shaped transformer is the preset value, and the compensation zero-sequence current of the static var generator is the difference value of the zero-sequence current of the Z-shaped transformer minus the compensation zero-sequence current of the Z-shaped transformer.
7. The apparatus of claim 5, wherein the zero sequence current compensation rule comprises:
the compensation zero-sequence current of the Z-shaped transformer is the preset value, and the compensation zero-sequence current of the static var generator is obtained by subtracting the compensation zero-sequence current of the Z-shaped transformer from the zero-sequence current of the load side; wherein the load side zero sequence current is obtained in advance.
8. The apparatus of any one of claims 5 to 7, further comprising:
and the second judging unit is used for determining that the zero-sequence current compensation is carried out by using the Z-type transformer independently after judging that the zero-sequence current of the Z-type transformer is smaller than or equal to the preset value.
9. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the steps of the method of any of claims 1 to 4 are implemented when the program is executed by the processor.
10. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 4.
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