CN115000975B

CN115000975B - Reactive compensation method of power distribution system and power distribution system

Info

Publication number: CN115000975B
Application number: CN202210929729.1A
Authority: CN
Inventors: 马庆华; 黄海宇; 金祖樑; 王莉; 李阳春; 李帮家; 王伟胜; 王文涛; 林武军
Original assignee: HANGZHOU DECHENG ELECTRIC POWER TECHNOLOGY CO LTD
Current assignee: HANGZHOU DECHENG ELECTRIC POWER TECHNOLOGY CO LTD
Priority date: 2022-08-04
Filing date: 2022-08-04
Publication date: 2022-12-30
Anticipated expiration: 2042-08-04
Also published as: CN115000975A

Abstract

The application provides a reactive power compensation method of a power distribution system and the power distribution system, and belongs to the technical field of electric power. The method comprises the following steps: acquiring real-time voltage of a compensation point in a power distribution system, and determining a real-time phase of the real-time voltage, wherein the compensation point is positioned on a three-phase output bus of the power distribution system; respectively determining the effective values of the three-phase real-time reactive current of the compensation points according to the real-time phase of the real-time voltage and the three-phase current output by the power distribution system at the first moment, wherein the first moment is the current moment; and determining the target reactive current which is required to be output by the static var generator aiming at the compensation point and the target phase line at present according to the effective value of the three-phase real-time reactive current, the number of the static var generators connected on the compensation point and at least one target phase line connected with the output end of the static var generator, and outputting the target reactive current to the target phase line. The reactive compensation device can achieve the effect of accurately and quickly outputting the reactive current to perform reactive compensation.

Description

Reactive compensation method of power distribution system and power distribution system

Technical Field

The application relates to the technical field of electric power, in particular to a reactive power compensation method of a power distribution system and the power distribution system.

Background

Generally can be through distribution system for the electric energy of power consumption load transmission, power consumption load not only needs active electric energy still needs reactive power, and the reactive power that power consumption load needs can have certain fluctuation to ensure that distribution system does not transship or the active power of distribution system output can not reduce, just need set up reactive compensation equipment in distribution system and carry out reactive compensation.

In the related art, a Static Var Generator (SVG) is generally used to calculate a load reactive current to be compensated by collecting a current on a grid side and a voltage of a power distribution system, and the SVG outputs a current having the same magnitude and the opposite direction to the load reactive current, so as to achieve the purpose of reactive compensation.

However, since the value of the reactive current to be compensated may exceed the maximum reactive current that can be output by one SVG, multiple SVGs need to be connected in parallel so that the multiple SVGs can output reactive current in a balanced manner, but communication connection needs to be established between the multiple SVGs, and one master SVG is provided to control the other SVGs, which results in slow response speed of the SVG. Therefore, the scheme in the related art has the problem that reactive current cannot be output quickly and accurately under the condition that reactive compensation is required to be performed by using a plurality of SVGs.

Disclosure of Invention

The application aims to provide a reactive compensation method of a power distribution system and the power distribution system, and the effect of accurately and quickly outputting reactive current to perform reactive compensation can be achieved.

The embodiment of the application is realized as follows:

in a first aspect of the embodiments of the present application, a reactive power compensation method for a power distribution system is provided, where the method is applied to any static var generator in the power distribution system, where a plurality of static var generators connected in parallel are deployed in the power distribution system, and the method includes: acquiring real-time voltage of a compensation point in the power distribution system, and determining a real-time phase of the real-time voltage, wherein the compensation point is positioned on a three-phase output bus of the power distribution system, and the real-time phase comprises a first phase of a U-phase voltage, a second phase of a V-phase voltage and a third phase of a W-phase voltage;

respectively determining effective values of three-phase real-time reactive current of the compensation points according to the real-time phase of the real-time voltage and three-phase current output by the power distribution system at a first moment, wherein the first moment is the current moment;

according to the effective value of the three-phase real-time reactive current, the number of the static var generators connected to the compensation point and at least one target phase line connected to the output end of the static var generator, the target reactive current which is required to be output by the static var generator at the compensation point and the target phase line at present is determined, and the target reactive current is output to the target phase line.

Optionally, the determining, according to the effective value of the three-phase real-time reactive current, the number of the static var generators connected to each compensation point, and at least one target phase line connected to the output end of the static var generator, a target reactive current that needs to be output currently includes:

reading the effective value of the target real-time reactive current on the target phase line from the effective value of the three-phase real-time reactive current;

determining total compensation current on the target phase line according to the effective value of the target real-time reactive current, the time constant of an inertia link in the static var generator and the proportionality coefficient of the inertia link;

and determining the target reactive current which needs to be output by the static var generator aiming at the compensation point and the target phase line currently according to the total compensation current and the number of the static var generators connected to the compensation point.

Optionally, the method further comprises:

adjusting a proportionality coefficient of an inertia link in the static var generator, and acquiring change information of reactive current of the power distribution system, wherein the change information is used for indicating increase or decrease of the reactive current of the power distribution system;

and determining the installation state of a current transformer in the power distribution system and adjusting the three-phase current of the power distribution system acquired by the current transformer according to the change information, wherein the installation state is used for indicating whether the current transformer is installed correctly.

Optionally, the determining, according to the real-time phase of each real-time voltage and the three-phase current output by the power distribution system at the first time, the effective value of the three-phase real-time reactive current of each compensation point respectively includes:

acquiring three-phase currents output by the power distribution system at the first moment, wherein the three-phase currents output by the power distribution system at the first moment comprise a first U-phase current, a first V-phase current and a first W-phase current;

and determining the effective value of the three-phase real-time reactive current of the compensation point according to the first phase, the second phase, the third phase, the first U-phase current, the first V-phase current and the first W-phase current.

Optionally, the determining, according to the first phase, the second phase, the third phase, the first U-phase current, the first V-phase current, and the first W-phase current, the effective value of the three-phase real-time reactive current of the compensation point includes:

determining an effective value of a first real-time reactive current of a compensation point on a U-phase output bus according to a first phase, the first U-phase current, a second U-phase current output by the power distribution system at a second moment, a third U-phase current output by the power distribution system at a third moment, a U-phase reactive current at the second moment and a U-phase reactive current at the third moment, wherein the second moment is before the first moment and the third moment is before the second moment;

determining an effective value of a second real-time reactive current of a compensation point on a V-phase output bus according to a second phase, the first V-phase current, a second V-phase current output by the power distribution system at a second moment, a third V-phase current output by the power distribution system at a third moment, a V-phase reactive current at the second moment and a V-phase reactive current at the third moment;

and determining an effective value of a third real-time reactive current of a compensation point on a W-phase output bus according to a third phase, the first W-phase current, a second W-phase current output by the power distribution system at a second moment, a third W-phase current output by the power distribution system at a third moment, a W-phase reactive current at the second moment and a W-phase reactive current at the third moment.

Optionally, the determining, according to the first phase, the first U-phase current, the second U-phase current output by the power distribution system at the second time, the third U-phase current output by the power distribution system at the third time, the U-phase reactive current at the second time, and the U-phase reactive current at the third time, the effective value of the first real-time reactive current of the compensation point on the U-phase output bus includes:

and determining the effective value of the first real-time reactive current of the compensation point on the U-phase output bus according to the first phase, the first U-phase current, the second U-phase current, the third U-phase current, the U-phase reactive current at the second moment, the U-phase reactive current at the third moment and the filter coefficient of a low-pass filter in the static var generator.

Optionally, the determining an effective value of a second real-time reactive current of a compensation point on a V-phase output bus according to the second phase, the first V-phase current, a second V-phase current output by the power distribution system at a second moment, a third V-phase current output by the power distribution system at a third moment, a V-phase reactive current at the second moment, and a V-phase reactive current at the third moment includes:

and determining the effective value of the second real-time reactive current of the compensation point on the V-phase output bus according to the second phase, the first V-phase current, the second V-phase current, the third V-phase current, the V-phase reactive current at the second moment, the V-phase reactive current at the third moment and the filter coefficient of the low-pass filter.

Optionally, the determining an effective value of a third real-time reactive current of a compensation point on a W-phase output bus according to a third phase, the first W-phase current, a second W-phase current output by the power distribution system at a second moment, a third W-phase current output by the power distribution system at a third moment, a W-phase reactive current at the second moment, and a W-phase reactive current at the third moment includes:

and determining the effective value of the third real-time reactive current of the compensation point on the W-phase output bus according to the third phase, the first W-phase current, the second W-phase current, the third W-phase current, the W-phase reactive current at the second moment, the W-phase reactive current at the third moment and the filter coefficient of the low-pass filter.

Optionally, after determining, according to the effective value of the three-phase real-time reactive current, the number of the static var generators connected at the compensation point, and at least one target phase line to which an output end of the static var generator is connected, a target reactive current that the static var generator currently needs to output for the compensation point and the target phase line, and outputting the target reactive current to the target phase line, the method further includes:

and under the condition that the static var generator stably outputs the target reactive current to electric equipment, determining the three-phase current output by the power distribution system according to the current of the electric equipment, the transformation ratio of a current transformer and the proportionality coefficient of an inertia link in the static var generator.

In a second aspect of embodiments of the present application, there is provided a power distribution system comprising a distribution transformer, at least one current transformer, a plurality of static var generators;

the output end of the distribution transformer is respectively used for connecting electric equipment, the output end of each current transformer is respectively connected with the input end of each static var generator, and the output end of each static var generator is respectively connected with the output end of the distribution transformer;

each output of distribution transformer is respectively distribution system's three-phase output bus, three-phase output bus includes: a U-phase output bus, a V-phase output bus and a W-phase output bus;

each current transformer is used for collecting the current of a three-phase output bus;

each static var generator is used for obtaining real-time voltage of a compensation point in the power distribution system and determining real-time phase of the real-time voltage, each static var generator is further used for determining an effective value of three-phase real-time reactive current of the compensation point according to the real-time phase of the real-time voltage and three-phase current output by the power distribution system at a first moment, and each static var generator is further used for determining target reactive current which is required to be output by the static var generator aiming at the compensation point and the target phase line currently according to the effective value of the three-phase real-time reactive current, the number of the static var generators connected to the compensation point and at least one target phase line connected to the output end of the static var generator, and outputting the target reactive current to the target phase line.

The beneficial effects of the embodiment of the application include:

according to the reactive compensation method of the power distribution system, the real-time voltage of the compensation point in the power distribution system is obtained, the real-time phase of the real-time voltage is determined, and the effective values of the three-phase real-time reactive currents of the compensation point are respectively determined according to the real-time phase of the real-time voltage and the three-phase currents output by the power distribution system at the first moment, so that the effective values of the real-time reactive currents output by the power distribution system to the U-phase output bus, the V-phase output bus and the W-phase output bus at the first moment can be accurately determined.

According to the effective value of the three-phase real-time reactive current, the quantity of the SVG connected to the compensation point and at least one target phase line connected to the output end of the SVG, the target reactive current which is required to be output by the SVG aiming at the compensation point and the target phase line is determined, and the target reactive current is output to the target phase line. When reactive compensation is carried out, only the phase line corresponding to the phase voltage used by the electric equipment during working is needed to be used as a target phase line for reactive compensation, and reactive compensation can not be carried out on the phase line corresponding to the phase voltage which is not used during working of the electric equipment or the phase line which is not needed to be carried out with reactive compensation, so that the problem of unbalanced three-phase reactive current caused by reactive compensation can be avoided. Therefore, reactive current output by each SVG to a phase line needing reactive compensation can be respectively determined, and under the condition that a plurality of SVGs are connected in parallel, the sum of target reactive current output by all the SVGs to each target phase line is the reactive current compensated to each target phase line. And then, correspondingly outputting the target reactive current to the target phase line by the SVG, so that the aim of reactive compensation can be fulfilled.

In addition, including the parallelly connected condition of many SVGs in this distribution system, each SVG can all accurately calculate the reactive current of each SVG to the phase line output that needs to carry out reactive compensation according to this three-phase real-time reactive current's effective value, the quantity of the SVG of connecting on this compensation point and at least one target phase line that the output of each SVG is connected, that is to say, need not carry out communication connection between each SVG when carrying out reactive compensation, also need not set up another SVG and control other SVG, like this, just can promote the response speed of each SVG output reactive current by a wide margin.

Therefore, the effect of accurately and quickly outputting the reactive current to perform reactive compensation can be achieved.

In addition, since the real-time phase of the real-time voltage and the three-phase current output by the power distribution system at the first moment respectively determine the effective value of the three-phase real-time reactive current of the compensation point, the current at the load side does not need to be acquired, so that a new load side CT is not needed, the cost can be reduced, and the transformation ratio of the CT and the total capacity of each SVG for reactive compensation when multiple machines are connected in parallel are not needed to be set.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

Fig. 1 is a flowchart of a reactive compensation method for a first power distribution system according to an embodiment of the present disclosure;

fig. 2 is a flowchart of a reactive compensation method of a second power distribution system according to an embodiment of the present disclosure;

fig. 3 is a flowchart of a reactive compensation method of a third power distribution system according to an embodiment of the present application;

fig. 4 is a flowchart of a reactive compensation method for a fourth power distribution system according to an embodiment of the present application;

fig. 5 is a flowchart of a reactive compensation method for a fifth power distribution system according to an embodiment of the present disclosure;

fig. 6 is a flowchart of a reactive power compensation method for a sixth power distribution system according to an embodiment of the present disclosure;

fig. 7 is a flowchart of a reactive compensation method for a seventh power distribution system according to an embodiment of the present application;

fig. 8 is a schematic structural diagram of a power distribution system according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present application, it should be noted that, unless otherwise specifically stated or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

During the operation of some electrical devices, there is often reactive power and active power, and the reactive power often plays a role in excitation to ensure the proper operation of the electrical devices. For example, a magnetic load such as a motor or a transformer needs a certain reactive power to perform excitation. Generally, electric energy is transmitted to an electric load through a power distribution system, and reactive power required by the electric load has certain fluctuation, so that reactive compensation equipment needs to be arranged in the power distribution system in order to ensure that the power distribution system is not overloaded or active power output by the power distribution system is not reduced.

In the related art, a Static Var Generator (SVG) is generally used to calculate a load reactive current to be compensated by collecting a current on a grid side and a voltage of a power distribution system, and the SVG outputs a current having the same magnitude and the opposite direction to the load reactive current, so as to achieve the purpose of reactive compensation. However, since the value of the reactive current to be compensated may exceed the maximum reactive current that can be output by one SVG, multiple SVGs need to be connected in parallel so that the multiple SVGs can output reactive current in a balanced manner, but communication connection needs to be established between the multiple SVGs, and one master SVG is provided to control the other SVGs, which results in slow response speed of the SVG. Therefore, when reactive power compensation needs to be performed by using a plurality of SVGs, the scheme in the related art has a problem that reactive current cannot be output quickly and accurately.

In addition, the load reactive Current to be compensated can be calculated by collecting the Current on the load side and the voltage of the power distribution system through the SVG, but because only one Current Transformer (CT for short) on the power grid side is installed in the existing power distribution system, if the scheme is adopted, one new load side CT is needed to be added to collect the Current on the load side. In addition, in the case of parallel connection of multiple machines, the transformation ratio of the CT and the total capacity of each SVG for reactive power compensation when the multiple machines are connected in parallel need to be set, and once the setting is wrong, the problem that the reactive current cannot be correctly compensated is caused. That is to say, this solution needs to perform parameter setting on CT and SVG before performing reactive power compensation each time, and therefore, this solution has the problems of poor reliability, low efficiency and high cost.

Therefore, the embodiment of the application provides a reactive power compensation method of a power distribution system, which includes acquiring a real-time voltage of a compensation point in the power distribution system, determining a real-time phase of the real-time voltage, determining effective values of three-phase real-time reactive currents of the compensation point according to the real-time phase of the real-time voltage and three-phase currents output by the power distribution system at a first moment, determining a target reactive current which needs to be output by a static reactive generator aiming at the compensation point and the target phase line currently according to the effective values of the three-phase real-time reactive currents, the number of static reactive generators connected to the compensation point and at least one target phase line connected to an output end of the static reactive generator, and outputting the target reactive current to the target phase line, so that an effect of accurately and quickly outputting reactive current to perform reactive power compensation can be achieved.

The embodiment of the present application takes a reactive compensation method applied in a power distribution system as an example for explanation. It is not intended that the embodiments of the present application be applicable only to reactive compensation in power distribution systems.

The reactive compensation method of the power distribution system provided by the embodiment of the present application is explained in detail below.

Fig. 1 is a flowchart of a reactive power compensation method for a power distribution system, which can be applied to any SVG in the power distribution system, where multiple SVGs connected in parallel are deployed in the power distribution system. Referring to fig. 1, an embodiment of the present application provides a reactive power compensation method for a power distribution system, including:

step 1001: a real-time voltage of a compensation point in the power distribution system is obtained, and a real-time phase of the real-time voltage is determined.

Optionally, the compensation point is located on a three-phase output bus of the power distribution system. The three-phase output bus can comprise a U-phase output bus, a V-phase output bus and a W-phase output bus.

Alternatively, the real-time voltage may be a three-phase voltage or a single-phase voltage. The real-time voltage may include a U-phase voltage, a V-phase voltage, and a W-phase voltage output by the power distribution system.

In addition, the real-time voltage may be collected by a voltage transformer installed in the power distribution system and output to the SVG by the voltage transformer. The real-time voltage can be collected by any other device capable of collecting voltage and output to the SVG. The embodiments of the present application do not limit this.

The real-time phases may include a first phase of a U-phase voltage, a second phase of a V-phase voltage, and a third phase of a W-phase voltage.

For example, the real-time phase may be calculated by a cosine law, may be locked by a phase-locked loop in the SVG, and may be obtained by any other possible method, which is not limited in this embodiment of the present application.

Therefore, the reactive current required to be compensated at the compensation point and the reactive current required to be output by the SVG can be conveniently calculated subsequently.

Step 1002: and respectively determining the effective values of the three-phase real-time reactive current of the compensation point according to the real-time phase of the real-time voltage and the three-phase current output by the power distribution system at the first moment.

Optionally, the first time is a current time.

Optionally, the three-phase current output by the power distribution system at the first time may include a first U-phase current, a first V-phase current, and a first W-phase current. The phase currents may specifically include active and reactive currents of the phases.

The three-phase real-time reactive current may include a first real-time reactive current of a compensation point on the U-phase output bus, a second real-time reactive current of a compensation point on the V-phase output bus, and a third real-time reactive current of a compensation point on the W-phase output bus. Then, the effective values of the three-phase real-time reactive currents may include an effective value of the first real-time reactive current, an effective value of the second real-time reactive current, and an effective value of the third real-time reactive current.

It is worth mentioning that the real-time reactive current effective values output to the U-phase output bus, the V-phase output bus and the W-phase output bus by the power distribution system at the first moment can be accurately determined through the three-phase current output by the power distribution system at the first moment, so that the reactive current values required by the SVG for compensation of the U-phase, the V-phase and/or the W-phase can be conveniently calculated subsequently, and the compensation of the reactive current can be completed.

Step 1003: according to the effective value of the three-phase real-time reactive current, the quantity of the SVG connected to the compensation point and at least one target phase line connected to the output end of the SVG, the target reactive current which is required to be output by the SVG aiming at the compensation point and the target phase line is determined, and the target reactive current is output to the target phase line.

Optionally, the number of SVGs connected to the compensation point may refer to the number of SVGs connected to the phase line of the compensation point. The quantity of the SVG of connecting on this compensation point is adjusted by relevant technical staff according to actual conditions to can be in advance input the quantity of the SVG of connecting on this compensation point into each SVG by relevant technical staff, SVG also can acquire the quantity of the SVG of connecting on this compensation point in real time through other arbitrary modes, and this application embodiment does not limit this.

Optionally, the target phase line may refer to a phase line that needs to be reactive compensation in the three-phase output bus, and the target phase line may also refer to any phase line connected to the SVG output terminal.

The target phase line may be any one phase line in the three-phase output bus, may also be any two phase lines in the three-phase output bus, and may also be all phase lines in the three-phase output bus, which may be specifically selected according to actual needs, and this is not limited in this embodiment of the application.

In addition, because the compensation point is located on the three-phase output bus of the power distribution system, and the target phase line is the phase line which needs to be subjected to reactive compensation in the three-phase output bus, then, the target reactive current which is required to be output by the SVG aiming at the compensation point and the target phase line at present can refer to the reactive current which is output by the SVG aiming at the phase line which needs to be subjected to reactive compensation.

The target reactive current may refer to a reactive current actually output by the SVG to the target phase line.

It is worth noting that three-phase power supply is generally used in an electric power system, most electric equipment can work only by using three-phase voltage, but due to the working characteristics of some electric equipment, when the electric equipment works, only one-phase voltage or two-phase voltage is often used, under the condition, the one-phase voltage or the two-phase voltage is not used, then, when reactive compensation is carried out, only the phase line corresponding to the phase voltage used when the electric equipment works is used as a target phase line for reactive compensation, and the phase line corresponding to the phase voltage which is not used when the electric equipment works or the phase line which is not required to be subjected to reactive compensation can not be subjected to reactive compensation, so that the problem of unbalanced three-phase reactive current caused by reactive compensation can be ensured.

In addition, the output of this SVG can be connected with arbitrary phase line in this three-phase output bus in order to carry out reactive compensation, if the output of this SVG only with a phase line connection in this three-phase output bus, then this SVG just carries out reactive compensation for this phase line only, if the output of this SVG only with two phase line connections in this three-phase output bus, then this SVG just carries out reactive compensation for this phase line only, if the output of this SVG only with this three-phase output bus in all phase line connections, then this SVG just can carry out reactive compensation for all phase lines in this three-phase output bus.

It is worth explaining that the target reactive current which is output by the SVG aiming at the compensation point and the target phase line at present can be determined according to the effective value of the three-phase real-time reactive current, the number of the SVGs connected to the compensation point and at least one target phase line connected to the output end of the SVG, so that the reactive current which is output by each SVG aiming at the phase line needing reactive compensation can be respectively determined, therefore, under the condition that a plurality of SVGs are connected in parallel, the effect that the target reactive currents which are output by each SVG connected to the compensation point and the target phase line are the same can be realized, and the sum of the target reactive currents which are output by each SVG to each target phase line is the reactive current compensated for each target phase line. Then, the SVG correspondingly outputs the target reactive current to the target phase line, so that the purpose of reactive compensation can be realized.

In the embodiment of the application, by acquiring the real-time voltage of the compensation point in the power distribution system, determining the real-time phase of the real-time voltage, and respectively determining the effective values of the three-phase real-time reactive currents of the compensation point according to the real-time phase of the real-time voltage and the three-phase currents output by the power distribution system at the first moment, the effective values of the real-time reactive currents output by the power distribution system to the U-phase output bus, the V-phase output bus and the W-phase output bus at the first moment can be accurately determined.

According to the effective value of the three-phase real-time reactive current, the quantity of the SVG connected to the compensation point and at least one target phase line connected to the output end of the SVG, the target reactive current which is required to be output by the SVG aiming at the compensation point and the target phase line is determined, and the target reactive current is output to the target phase line. When reactive compensation is carried out, only the phase line corresponding to the phase voltage used by the electric equipment during working is needed to be used as a target phase line for reactive compensation, and reactive compensation can not be carried out on the phase line corresponding to the phase voltage which is not used during working of the electric equipment or the phase line which is not needed to be carried out with reactive compensation, so that the problem of unbalanced three-phase reactive current caused by reactive compensation can be avoided. Therefore, reactive current output by each SVG to a phase line needing reactive compensation can be respectively determined, and under the condition that a plurality of SVGs are connected in parallel, the sum of target reactive current output by all the SVGs to each target phase line is the reactive current compensated to each target phase line. Then, the SVG correspondingly outputs the target reactive current to the target phase line, so that the purpose of reactive compensation can be realized.

In one possible implementation, referring to fig. 2, determining a target reactive current to be currently output according to an effective value of the three-phase real-time reactive current, the number of SVGs connected at each compensation point, and at least one target phase line to which an output terminal of the SVG is connected includes:

step 1004: and reading the effective value of the target real-time reactive current on the target phase line from the effective values of the three-phase real-time reactive current.

Optionally, the target real-time reactive current may comprise a first real-time reactive current, a second real-time reactive current and/or a third real-time reactive current. The effective value of the target real-time reactive current may then comprise an effective value of the first real-time reactive current, an effective value of the second real-time reactive current and/or an effective value of the third real-time reactive current.

It should be noted that, because the effective values of the three-phase real-time reactive current may include an effective value of a first real-time reactive current, an effective value of a second real-time reactive current, and an effective value of a third real-time reactive current, and at least one target phase line connected to the output end of the SVG may be any one phase line, any two phase lines, or all phase lines in the three-phase output bus, it is necessary to read the effective value of the target real-time reactive current on the target phase line from the effective value of the three-phase real-time reactive current according to the bus connected to the output end of the SVG.

For example, if the output terminal of the SVG is connected to the U-phase output bus, it is only necessary to read the first real-time reactive current from the connected effective values of the three-phase real-time reactive currents as the effective value of the target real-time reactive current. If the U-phase output bus and the V-phase output bus are connected respectively according to the output end of the SVG, the effective value of the first real-time reactive current and the effective value of the second real-time reactive current are only required to be read from the connected effective values of the three-phase real-time reactive current to serve as the effective value of the target real-time reactive current. If the U-phase output bus, the V-phase output bus and the W-phase output bus are connected respectively according to the output end of the SVG, then the effective value of the first real-time reactive current, the effective value of the second real-time reactive current and the effective value of the third real-time reactive current need to be read from the effective values of the three-phase real-time reactive currents which are connected as the effective value of the target real-time reactive current.

Step 1005: and determining the total compensation current on the target phase line according to the effective value of the target real-time reactive current, the time constant of an inertia link in the SVG and the proportionality coefficient of the inertia link.

Optionally, the inertia element includes an energy storage element, so the inertia element may prevent an abrupt input signal from being repeated immediately, that is, the output of the inertia element does not change proportionally with the input signal at the beginning until the end of the transition process. The time constant of the inertial element is a measure of the magnitude of the inertia.

Alternatively, the total compensation current may refer to the reactive current on the target phase line that needs to be compensated. The total compensation current may refer to a direct current component of the alternating current, and may also refer to a direct current, which is not limited in the embodiment of the present application.

Optionally, the speed of the SVG for performing reactive power compensation can be changed by adjusting the time constant of the inertia link, and generally, the smaller the time constant of the inertia link is, the faster the SVG performs reactive power compensation.

Can change this SVG through the proportionality coefficient of adjusting this inertia link and carry out reactive compensation's compensation effect, generally, the proportionality coefficient of this inertia link is big more, and this SVG carries out reactive compensation's compensation effect better.

Illustratively, the total compensation current may be calculated using the following equation (1).

（1）

Wherein,

for the effective value of the target real-time reactive current,

for the purpose of this total compensation current it is,

is the time constant of the inertial element,

is the proportionality coefficient of the inertia link.

Therefore, the value of the reactive current which needs to be compensated for the target phase line can be accurately determined, and then subsequent accurate reactive compensation is facilitated.

Step 1006: and determining the target reactive current which needs to be output by the SVG aiming at the compensation point and the target phase line currently according to the total compensation current and the quantity of the SVG connected to the compensation point.

It should be noted that, since the total compensation current may refer to the reactive current that needs to be compensated on the target phase line, the target reactive current that needs to be output by the SVG at present can be obtained by distributing the total compensation current to each SVG.

For example, if the number of SVGs connected at the compensation point is 3, the value obtained by dividing the total compensation current by 3 may be used as the target reactive current that the SVG needs to output currently for the compensation point and the target phase line.

It should be noted that, under the condition that multiple SVG machines are connected in parallel, in order to enable multiple SVGs to output reactive current in a balanced manner, that is, in order to achieve the purpose of equalizing the current of multiple SVGs, the reactive current to be compensated needs to be distributed to each SVG, and each SVG outputs the same reactive current to compensate.

In one possible implementation, referring to fig. 3, the method further includes:

step 1007: and adjusting the proportional coefficient of an inertia link in the SVG, and acquiring the change information of the reactive current of the power distribution system.

Optionally, the change information is used to indicate an increase or decrease in reactive current output by the power distribution system.

The operation of adjusting the proportionality coefficient of the inertia link in the SVG may specifically be increasing or decreasing the proportionality coefficient of the inertia link.

In addition, the proportionality coefficient of the inertia link in the SVG can be adjusted once every interval of time, and the proportionality coefficient of the inertia link in the SVG can also be adjusted once after the SVG is powered on.

It is worth to be noted that, because the compensation effect of the SVG for performing reactive power compensation can be changed by adjusting the proportionality coefficient of the inertia link, the target reactive current output by the SVG changes correspondingly after the proportionality coefficient of the inertia link is adjusted.

Exemplarily, if the proportionality coefficient of the inertia link is increased, the compensation effect of reactive compensation performed by the SVG becomes stronger, then the target reactive current output by the SVG becomes larger, and since the SVG outputs a larger target reactive current and the reactive current or reactive power required by the electric equipment does not change, the reactive current output by the power distribution system is correspondingly reduced. If reduce the proportionality coefficient of this inertia link, this SVG carries out reactive compensation's compensation effect will become worse, and then the target reactive current of this SVG output will diminish, because this SVG has exported littleer target reactive current, and the reactive current or the reactive power that consumer needs can not change, and the reactive current of this distribution system output will increase correspondingly.

Step 1008: and determining the installation state of a current transformer in the power distribution system according to the change information, and adjusting the three-phase current of the power distribution system acquired by the current transformer.

Optionally, the current transformer may be installed at an output end of the power distribution system to collect three-phase voltages output by the power distribution system, and the current transformer may be further configured to output the collected three-phase voltages to each SVG. The installation state is used for indicating whether the current transformer is installed correctly.

For example, after the scaling factor of the inertia element is increased, if the obtained change information indicates that the reactive current output by the power distribution system is decreased, it may be determined that the current transformer is installed correctly, and if the obtained change information indicates that the reactive current output by the power distribution system is increased, it may be determined that the current transformer is installed incorrectly, and it may be further determined that the current transformer is reversely connected.

For another example, after the scaling factor of the inertia element is reduced, if the obtained change information indicates that the reactive current output by the power distribution system increases, it may be determined that the current transformer is correctly installed, and if the obtained change information indicates that the reactive current output by the power distribution system decreases, it may be determined that the current transformer is incorrectly installed, and it may be further determined that the current transformer is reversely connected.

In a possible mode, under the condition that the current transformer is determined to be reversely connected, the SVG can also perform reverse processing on the acquired three-phase current output by the power distribution system at the first moment so as to accurately recalculate the target reactive current required to be output by the SVG.

In a possible mode, in the case of determining that the current transformer is reversely connected, the SVG can stop outputting the target reactive current, and at the same time, can generate and output a corresponding prompt message to inform a related technician of processing.

Therefore, whether the current transformer of the power distribution system is installed correctly or not can be accurately determined, and the reliability and accuracy of reactive compensation can be further improved.

In one possible implementation, referring to fig. 4, determining the effective value of the three-phase real reactive current of the compensation point according to the real-time phase of each real-time voltage and the three-phase current output by the power distribution system at the first time includes:

step 1009: and acquiring the three-phase current output by the power distribution system at the first moment.

The three-phase current output by the power distribution system at the first moment comprises a first U-phase current, a first V-phase current and a first W-phase current.

Optionally, the three-phase current output by the power distribution system at the first moment may be collected by the current transformer, and the three-phase current is output to each SVG by the current transformer, or the three-phase current may be collected by any other device or apparatus capable of collecting the three-phase current output by the power distribution system and output to each SVG, which is not limited in this embodiment of the present application.

Step 1010: and determining the effective value of the three-phase real-time reactive current of the compensation point according to the first phase, the second phase, the third phase, the first U-phase current, the first V-phase current and the first W-phase current.

It should be noted that the three-phase real-time reactive current of the compensation point, that is, the instantaneous reactive current on each phase line, may be determined through the first phase, the second phase, the third phase, the first U-phase current, the first V-phase current, and the first W-phase current, and then the effective value of the three-phase real-time reactive current of the compensation point may be calculated according to the three-phase real-time reactive current of the compensation point.

Therefore, the effective value of the three-phase real-time reactive current of the compensation point can be accurately calculated, and the numerical value of the reactive current which needs to be compensated for the U phase, the V phase and/or the W phase of the SVG can be conveniently calculated subsequently, so that the compensation of the reactive current is completed.

In one possible implementation, referring to fig. 5, determining an effective value of the three-phase real reactive current of the compensation point according to the first phase, the second phase, the third phase, the first U-phase current, the first V-phase current, and the first W-phase current includes:

step 1011: and determining an effective value of a first real-time reactive current of a compensation point on a U-phase output bus according to the first phase, the first U-phase current, a second U-phase current output by the power distribution system at the second moment, a third U-phase current output by the power distribution system at the third moment, the U-phase reactive current at the second moment and the U-phase reactive current at the third moment.

Optionally, the second time is before the first time, and the third time is before the second time.

In addition, the three-phase current output by the power distribution system is acquired according to a time sequence. The first time, the second time and the third time can be respectively used as collecting times for collecting three-phase currents output by the power distribution system.

For example, in a case where the first time is the first time arranged in the time series, that is, in a case where the current time is the time at which the three-phase current output by the power distribution system is collected for the first time, and the second time and the third time do not exist before the first time, the effective value of the first real-time reactive current of the compensation point on the U-phase output bus may be determined only based on the first phase and the first U-phase current.

For another example, if the second time is the first time arranged in the time series, that is, if the current time is the time at which the three-phase currents output by the power distribution system are collected for the second time, and the third time does not exist before the first time, the effective value of the first real-time reactive current at the compensation point on the U-phase output bus may be determined only based on the first phase, the first U-phase current, the second U-phase current output by the power distribution system at the second time, and the U-phase reactive current at the second time.

Step 1012: and determining the effective value of the second real-time reactive current of the compensation point on the V-phase output bus according to the second phase, the first V-phase current, the second V-phase current output by the power distribution system at the second moment, the third V-phase current output by the power distribution system at the third moment, the V-phase reactive current at the second moment and the V-phase reactive current at the third moment.

For example, in a case where the first time is the first time arranged in the time series, that is, in a case where the current time is the time at which the three-phase currents output by the power distribution system are collected for the first time, the second time and the third time do not exist before the first time, then the effective value of the second real-time reactive current of the compensation point on the V-phase output bus may be determined only according to the first phase and the first V-phase current.

For another example, if the second time is the first time arranged in the time series, that is, if the current time is the time at which the three-phase current output by the power distribution system is collected for the second time, and the third time does not exist before the first time, the effective value of the second real-time reactive current at the compensation point on the V-phase output bus may be determined only based on the first phase, the first V-phase current, the second V-phase current output by the power distribution system at the second time, and the V-phase reactive current at the second time.

Step 1013: and determining an effective value of a third real-time reactive current of a compensation point on the W-phase output bus according to the third phase, the first W-phase current, a second W-phase current output by the power distribution system at the second moment, a third W-phase current output by the power distribution system at the third moment, a W-phase reactive current at the second moment and a W-phase reactive current at the third moment.

For example, in a case where the first time is the first time arranged in the time series, that is, in a case where the current time is the time at which the three-phase currents output by the power distribution system are collected for the first time, the second time and the third time do not exist before the first time, then the effective value of the third real-time reactive current of the compensation point on the W-phase output bus may be determined only according to the first phase and the first W-phase current.

For another example, if the second time is the first time arranged in the time series, that is, if the current time is the time at which the three-phase current output by the power distribution system is collected for the second time, and the third time does not exist before the first time, the effective value of the third real-time reactive current at the compensation point on the W-phase output bus may be determined only based on the first phase, the first W-phase current, the second W-phase current output by the power distribution system at the second time, and the W-phase reactive current at the second time.

Therefore, the effective value of the first real-time reactive current of the compensation point on the U-phase output bus, the effective value of the second real-time reactive current of the compensation point on the V-phase output bus and the effective value of the third real-time reactive current of the compensation point on the W-phase output bus can be accurately calculated, and the numerical values of the reactive currents of the U-phase, the V-phase and/or the W-phase compensation needed by the SVG can be conveniently and subsequently calculated so as to complete the compensation of the reactive currents.

In one possible implementation, referring to fig. 6, determining an effective value of a first real reactive current of a compensation point on a U-phase output bus according to a first phase, the first U-phase current, a second U-phase current output by the power distribution system at a second time, a third U-phase current output by the power distribution system at a third time, a U-phase reactive current at the second time, and a U-phase reactive current at the third time includes:

step 1014: and determining the effective value of the first real-time reactive current of the compensation point on the U-phase output bus according to the first phase, the first U-phase current, the second U-phase current, the third U-phase current, the U-phase reactive current at the second moment, the U-phase reactive current at the third moment and the filter coefficient of the low-pass filter in the SVG.

Alternatively, the filter coefficient of the low-pass filter may be used to adjust the filter sensitivity and filter accuracy of the low-pass filter. Generally, the larger the filter coefficient, the higher the filtering accuracy of the low-pass filter, and the worse the filtering sensitivity. The smaller the filter coefficient is, the lower the filtering accuracy of the low-pass filter is, and the higher the filtering sensitivity is.

In one possible implementation, with continued reference to fig. 6, determining an effective value of a second real reactive current of a compensation point on a V-phase output bus according to a second phase, the first V-phase current, a second V-phase current output by the power distribution system at a second time, a third V-phase current output by the power distribution system at a third time, a V-phase reactive current at the second time, and a V-phase reactive current at the third time includes:

step 1015: and determining the effective value of the second real-time reactive current of the compensation point on the V-phase output bus according to the second phase, the first V-phase current, the second V-phase current, the third V-phase current, the V-phase reactive current at the second moment, the V-phase reactive current at the third moment and the filter coefficient of the low-pass filter.

In one possible implementation, with continued reference to fig. 6, determining an effective value of a third real-time reactive current of a compensation point on a W-phase output bus according to a third phase, the first W-phase current, a second W-phase current output by the power distribution system at a second time, a third W-phase current output by the power distribution system at a third time, a W-phase reactive current at the second time, and a W-phase reactive current at the third time includes:

step 1016: and determining the effective value of the third real-time reactive current of the compensation point on the W-phase output bus according to the third phase, the first W-phase current, the second W-phase current, the third W-phase current, the W-phase reactive current at the second moment, the W-phase reactive current at the third moment and the filter coefficient of the low-pass filter.

For example, the instantaneous reactive current on each phase line can be calculated by the following equation (2)

。

（3）

Wherein,

the collected three-phase current output by the power distribution system,

the real-time phase may be the above-mentioned real-time phase, and x represents a U-phase output bus, a V-phase output bus, and a W-phase output bus, respectively.

For example, x represents a U-phase output bus, then equation (2) above may be

. In the case of this situation, it is,

for the collected U-phase current output by the power distribution system,

is the phase of the U-phase voltage,

and outputting the instantaneous reactive current on the bus for the U phase.

Exemplarily, the effective value of the first real time reactive current, the effective value of the second real time reactive current, and the effective value of the third real time reactive current may then be determined using the following equation (3), respectively.

（3）

WhereinN represents an acquisition Point at a first time instant, n-1 represents an acquisition Point at a second time instant, and n-2 represents an acquisition Point at a third time instant, wherein

、

、

、

、

Are the filter coefficients of a low-pass filter,

x represents a U-phase output bus, a V-phase output bus and a W-phase output bus respectively for the instantaneous reactive current on each phase line,

the real-time reactive current effective value of each phase line is determined for the first moment,

the effective value of the reactive current of each phase line is determined for the second moment,

and determining the effective value of the reactive current of each phase line for the third moment.

Therefore, the effective value of the first real-time reactive current of the compensation point on the U-phase output bus, the effective value of the second real-time reactive current of the compensation point on the V-phase output bus and the effective value of the third real-time reactive current of the compensation point on the W-phase output bus can be accurately calculated, and the numerical values of the reactive currents which need to be compensated for the U-phase, the V-phase and/or the W-phase in the SVG can be conveniently calculated subsequently, so that the compensation of the reactive currents is completed.

In one possible implementation manner, referring to fig. 7, after determining, according to the effective value of the three-phase real-time reactive current, the number of SVGs connected at the compensation point, and at least one target phase line connected to the output end of the SVG, a target reactive current that the SVG currently needs to output for the compensation point and the target phase line, and outputting the target reactive current to the target phase line, the method further includes:

step 1017: under the condition that the target reactive current is stably output to the electric equipment by the SVG, the three-phase current output by the power distribution system is determined according to the current of the electric equipment, the transformation ratio of the current transformer and the proportionality coefficient of an inertia link in the SVG.

Optionally, the SVG stably outputs the target reactive current to the electric device may mean that output and input of an inertia link in the SVG are synchronously changed in proportion, or a transition process of the inertia link in the SVG is finished.

The current of the consumer may be referred to as the current on the load side.

Illustratively, the three-phase current output by the power distribution system may be determined using equation (4) below.

（4）

Wherein,

x represents a U-phase output bus, a V-phase output bus and a W-phase output bus respectively,

the current is the current of the load side or the current of the electric equipment, and the CT is the transformation ratio of the current transformer.

It is worth to say that after the three-phase current output by the power distribution system is determined according to the current of the electric equipment, the transformation ratio of the current transformer and the proportionality coefficient of the inertia link in the SVG, the effect of reactive power compensation can be verified through the three-phase current output by the power distribution system. Thus, the SVG can be adjusted according to the reactive compensation effect.

The following describes a power distribution system and the like for executing the reactive compensation method of the power distribution system provided by the present application, and specific implementation processes and technical effects thereof are referred to above, and will not be described again below.

Fig. 8 is a schematic structural diagram of a power distribution system provided in an embodiment of the present application, and referring to fig. 8, the power distribution system P includes a distribution transformer T, at least one current transformer CT, and a plurality of SVGs.

The output end of the distribution transformer T is respectively used for connecting the electric equipment F, the output end of the current transformer CT is respectively connected with the input end of each SVG, and the output end of each SVG is respectively connected with each output end of the distribution transformer T.

Each output end of the distribution transformer T is a three-phase output bus of the distribution system P.

Optionally, the three-phase output bus comprises: u looks output bus, V looks output bus, W looks output bus.

Optionally, the current transformer CT is used to collect the current of the three-phase output bus.

Optionally, each SVG is configured to obtain a real-time voltage of a compensation point in the power distribution system P, and determine a real-time phase of the real-time voltage, each SVG is further configured to determine an effective value of a three-phase real-time reactive current of the compensation point according to the real-time phase of the real-time voltage and a three-phase current output by the power distribution system P at a first time, each SVG is further configured to determine a target reactive current that the SVG needs to output currently for the compensation point and the target phase line according to the effective value of the three-phase real-time reactive current, the number of the SVGs connected to the compensation point, and at least one target phase line connected to an output end of the SVG, and output the target reactive current to the target phase line.

Optionally, each SVG may include a phase-locked loop, an inertia element, a low-pass filter, and the like.

The phase-locked loop may be used to determine the real-time phase of the real-time voltage at the compensation point in the power distribution system P. Specifically, the real-time voltage may be output to the phase-locked loops by the voltage transformer CT, and the phase-locked loops respectively lock the real-time phase of the real-time voltage and output the real-time phase to the low-pass filter.

Optionally, the above-mentioned instantaneous reactive current may be made by the low-pass filter

Reactive power is obtained and the effective value of the three-phase real-time reactive current of the compensation point can also be determined through the low-pass filter.

In addition, the effective value of the three-phase real-time reactive current of the compensation point can be output to the inertia link through the low-pass filter.

The inertia link can be used for determining the total compensation current on the target phase line according to the effective value of the target real-time reactive current, the time constant of the inertia link and the proportionality coefficient of the inertia link.

Optionally, each SVG may further include an output equalization module. The output balancing module is used for determining a target reactive current which is required to be output by the SVG aiming at the compensation point and the target phase line currently, and outputting the target reactive current to the electric equipment F.

The working principle of each element in the power distribution system P has been described in the foregoing embodiments, and specific reference may be made to the foregoing embodiments, which are not described herein again.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A reactive power compensation method of a power distribution system is applied to any static reactive power generator in the power distribution system, a plurality of parallel static reactive power generators are deployed in the power distribution system, and the method comprises the following steps:

acquiring real-time voltage of a compensation point in the power distribution system, and determining a real-time phase of the real-time voltage, wherein the compensation point is positioned on a three-phase output bus of the power distribution system, and the real-time phase comprises a first phase of a U-phase voltage, a second phase of a V-phase voltage and a third phase of a W-phase voltage;

according to the effective value of the three-phase real-time reactive current, the number of the static var generators connected to the compensation point and at least one target phase line connected to the output end of the static var generator, determining the target reactive current which is required to be output by the static var generator aiming at the compensation point and the target phase line currently, and outputting the target reactive current to the target phase line;

the determining the effective value of the three-phase real-time reactive current of the compensation point according to the real-time phase of each real-time voltage and the three-phase current output by the power distribution system at the first moment comprises the following steps:

determining an effective value of three-phase real-time reactive current of the compensation point according to the first phase, the second phase, the third phase, the first U-phase current, the first V-phase current and the first W-phase current;

the determining the effective value of the three-phase real-time reactive current of the compensation point according to the first phase, the second phase, the third phase, the first U-phase current, the first V-phase current and the first W-phase current comprises:

determining an effective value of a first real-time reactive current of a compensation point on a U-phase output bus according to a first phase, the first U-phase current, a second U-phase current output by a power distribution system at a second moment, a third U-phase current output by the power distribution system at a third moment, a U-phase reactive current at the second moment and a U-phase reactive current at the third moment, wherein the second moment is before the first moment, and the third moment is before the second moment;

and determining an effective value of a third real-time reactive current of a compensation point on the W-phase output bus according to a third phase, the first W-phase current, a second W-phase current output by the power distribution system at a second moment, a third W-phase current output by the power distribution system at a third moment, a W-phase reactive current at the second moment and a W-phase reactive current at the third moment.

2. The reactive compensation method for power distribution system according to claim 1, wherein the determining the target reactive current required to be output currently according to the effective value of the three-phase real reactive current, the number of the static var generators connected to each compensation point and at least one target phase line connected to the output end of the static var generator comprises:

3. A method of reactive compensation of an electrical distribution system as claimed in claim 1, wherein the method further comprises:

and determining the installation state of a current transformer in the power distribution system and adjusting the three-phase current of the power distribution system collected by the current transformer according to the change information, wherein the installation state is used for indicating whether the current transformer is installed correctly.

4. The reactive compensation method of an electric power distribution system of claim 1, wherein determining the effective value of the first real reactive current of the compensation point on the U-phase output bus from the first phase, the first U-phase current, the second U-phase current output by the electric power distribution system at the second time, the third U-phase current output by the electric power distribution system at the third time, the U-phase reactive current at the second time, and the U-phase reactive current at the third time comprises:

5. A reactive compensation method for an electrical distribution system as claimed in claim 1, wherein said determining an effective value of a second real reactive current for a compensation point on a V-phase output bus from a second phase, said first V-phase current, a second V-phase current output by said electrical distribution system at a second time, a third V-phase current output by said electrical distribution system at a third time, a V-phase reactive current at said second time, and a V-phase reactive current at said third time comprises:

and determining an effective value of a second real-time reactive current of a compensation point on a V-phase output bus according to the second phase, the first V-phase current, the second V-phase current, the third V-phase current, the V-phase reactive current at the second moment, the V-phase reactive current at the third moment and a filter coefficient of a low-pass filter.

6. The reactive compensation method of an electric power distribution system of claim 1, wherein determining an effective value of a third real reactive current of a compensation point on a W-phase output bus from a third phase, the first W-phase current, a second W-phase current output by the electric power distribution system at a second time, a third W-phase current output by the electric power distribution system at a third time, a W-phase reactive current at the second time, and a W-phase reactive current at the third time comprises:

7. A reactive power compensation method for an electric power distribution system according to any one of claims 1 to 6, wherein the method further comprises, after determining a target reactive current which the static var generator currently needs to output for the compensation point and the target phase line according to the effective value of the three-phase real reactive current, the number of the static var generators connected to the compensation point, and at least one target phase line connected to the output end of the static var generator, and outputting the target reactive current to the target phase line:

8. An electrical distribution system comprising a distribution transformer, at least one current transformer, a plurality of static var generators;

each static var generator is used for obtaining real-time voltage of a compensation point in the power distribution system and determining real-time phase of the real-time voltage, each static var generator is further used for determining an effective value of three-phase reactive current of the compensation point according to the real-time phase of the real-time voltage and three-phase current output by the power distribution system at a first moment, and each static var generator is further used for determining target reactive current which is required to be output by the static var generator aiming at the compensation point and the target phase line currently according to the effective value of the three-phase real reactive current, the number of the static var generators connected to the compensation point and at least one target phase line connected to the output end of the static var generator, and outputting the target reactive current to the target phase line;

each static var generator is further used for acquiring three-phase current output by the power distribution system at the first moment, the three-phase current output by the power distribution system at the first moment comprises a first U-phase current, a first V-phase current and a first W-phase current, and the effective value of the three-phase real-time reactive current of the compensation point is determined according to the first phase, the second phase, the third phase, the first U-phase current, the first V-phase current and the first W-phase current;

each static var generator is specifically configured to determine an effective value of a first real-time reactive current of a compensation point on a U-phase output bus according to a first phase, the first U-phase current, a second U-phase current output by the power distribution system at a second time, a third U-phase current output by the power distribution system at a third time, a U-phase reactive current at the second time, and a U-phase reactive current at the third time, where the second time is before the first time, and the third time is before the second time; determining an effective value of a second real-time reactive current of a compensation point on a V-phase output bus according to a second phase, the first V-phase current, a second V-phase current output by the power distribution system at a second moment, a third V-phase current output by the power distribution system at a third moment, a V-phase reactive current at the second moment and a V-phase reactive current at the third moment; and determining an effective value of a third real-time reactive current of a compensation point on the W-phase output bus according to a third phase, the first W-phase current, a second W-phase current output by the power distribution system at a second moment, a third W-phase current output by the power distribution system at a third moment, a W-phase reactive current at the second moment and a W-phase reactive current at the third moment.