CN112332425B

CN112332425B - Circular capacitor array reactive power compensation device

Info

Publication number: CN112332425B
Application number: CN202011173892.7A
Authority: CN
Inventors: 王鹏程; 陈炜; 莫洪亮; 王邢邢; 鲁晓枫; 马小平; 沈狄龙; 姚芳芳; 朱连芳; 张永军
Original assignee: Hangzhou Electric Power Equipment Manufacturing Co ltd Xiaoshan Xin Mei Complete Set Of Electrical Manufacturing Branch; Hangzhou Power Equipment Manufacturing Co Ltd; Hangzhou Xiaoshan District Power Supply Co of State Grid Zhejiang Electric Power Co Ltd
Current assignee: Hangzhou Electric Power Equipment Manufacturing Co ltd Xiaoshan Xin Mei Complete Set Of Electrical Manufacturing Branch; Hangzhou Xinmei Electrical Equipment Manufacturing Co ltd; Hangzhou Power Equipment Manufacturing Co Ltd; Hangzhou Xiaoshan District Power Supply Co of State Grid Zhejiang Electric Power Co Ltd
Priority date: 2020-10-28
Filing date: 2020-10-28
Publication date: 2022-04-05
Anticipated expiration: 2040-10-28
Also published as: CN112332425A

Abstract

The present application discloses a circular capacitor array reactive power compensation device, which relates to power equipment. In the device, first to Nth auxiliary switches are connected in series to form a ring; the first to Nth capacitor units are composed of capacitors and switching switches. connected in series; the first end of the first capacitor unit is connected to the connection point of the first auxiliary switch and the Nth auxiliary switch, and the first end of the Mth capacitor unit is connected to the M-1th auxiliary switch and The connection point of the Mth auxiliary switch; the second terminals of the first to Nth capacitor units are connected to each other; the first terminal of the first access switch is connected to the first terminal of the first capacitor unit, and the second access switch is connected to the first terminal of the first capacitor unit. The first ends of the two capacitor units are connected, and the first end of the third access switch is connected to the second end of the first capacitor unit. The invention can realize the access of various capacitance values through the combination of switches, and meets the reactive power compensation needs of the power system for large capacitance values and small capacitance values.

Description

Circular capacitor array reactive power compensation device

Technical Field

The application relates to power equipment, in particular to a circular capacitor array reactive power compensation device.

Background

In the current power grid operation system, the reactive compensation of the system mainly adopts a Fixed Capacitor (FC) and a Thyristor Switched Capacitor (TSC), and the system can perform rapid and deep reactive compensation so as to realize the optimization of the power quality. The FC and the TSC are simple, easy to operate, economical and the like, have good compensation characteristics, but with the improvement of the power quality requirement, the system puts forward higher requirements on reactive power regulation precision, and the fixed capacitance compensation of the TSC cannot meet the reactive power requirement of the system.

Disclosure of Invention

In view of this, the present application aims to: a circular capacitor array reactive power compensation device is provided to realize high-precision capacitance compensation.

In a first aspect, an embodiment of the present application provides:

a circular capacitor array reactive power compensation device, comprising: the first auxiliary switch, the second auxiliary switch, the third auxiliary switch, the fourth auxiliary switch, the fifth auxiliary switch, the sixth auxiliary switch, the seventh auxiliary switch, the eighth auxiliary switch, the first capacitor unit, the second capacitor unit, the third capacitor unit, the fourth capacitor unit, the fifth capacitor unit, the sixth capacitor unit, the seventh capacitor unit, the eighth capacitor unit, the first access switch, the second access switch and the third access switch;

the first auxiliary switch, the second auxiliary switch, the third auxiliary switch, the fourth auxiliary switch, the fifth auxiliary switch, the sixth auxiliary switch, the seventh auxiliary switch and the eighth auxiliary switch are sequentially connected in series to form a ring;

the first capacitor unit, the second capacitor unit, the third capacitor unit, the fourth capacitor unit, the fifth capacitor unit, the sixth capacitor unit, the seventh capacitor unit and the eighth capacitor unit are all formed by serially connecting a capacitor and a switching unit;

a first terminal of the first capacitance unit is connected to a connection point of the first auxiliary switch and the eighth auxiliary switch, a first terminal of the second capacitance unit is connected to a connection point of the first auxiliary switch and the second auxiliary switch, a first terminal of the third capacitance unit is connected to a connection point of the second auxiliary switch and the third auxiliary switch, a first terminal of the fourth capacitance unit is connected to a connection point of the third auxiliary switch and the fourth auxiliary switch, a first terminal of the fifth capacitance unit is connected to a connection point of the fourth auxiliary switch and the fifth auxiliary switch, a first end of the sixth capacitance unit is connected to a connection point of the fifth auxiliary switch and the sixth auxiliary switch, a first end of the seventh capacitive unit is connected to a connection point of the sixth auxiliary switch and the seventh auxiliary switch, a first end of the eighth capacitor unit is connected to a connection point of the seventh auxiliary switch and the eighth auxiliary switch;

a second end of the first capacitor unit, a second end of the second capacitor unit, a second end of the third capacitor unit, a second end of the fourth capacitor unit, a second end of the fifth capacitor unit, a second end of the sixth capacitor unit, a second end of the seventh capacitor unit, and a second end of the eighth capacitor unit are all connected to each other;

the first end of the first access switch is connected with the first end of the first capacitor unit, the second end of the first access switch is used as a first access point, the second access switch is connected with the first end of the second capacitor unit, the first end of the third access switch is connected with the second end of the first capacitor unit, and the second end of the second access switch is connected with the second end of the third access switch and used as a second access point.

In some embodiments, an access inductor is further connected to the second access point.

In some embodiments, each of the switching units is formed by connecting two thyristors in opposite directions in parallel.

In some embodiments, the capacitance values of each of the capacitors are the same.

In some embodiments, the apparatus further includes a controller for controlling the first auxiliary switch, the second auxiliary switch, the third auxiliary switch, the fourth auxiliary switch, the fifth auxiliary switch, the sixth auxiliary switch, the seventh auxiliary switch, the eighth auxiliary switch, the first access switch, the second access switch, the third access switch, and each of the switching units.

In some embodiments, the controller controls each switching unit based on a power frequency of a power grid, so that two thyristors in the switching unit are alternately switched on along with the power frequency of the power grid.

In a second aspect, embodiments of the present application provide:

a circular capacitor array reactive power compensation device, comprising: the first to Nth auxiliary switches, the first to Nth capacitance units, the first access switch, the second access switch and the third access switch, wherein N is a positive integer which is more than or equal to three and not equal to eight;

the first to Nth auxiliary switches are sequentially connected in series to form a ring;

the first capacitor unit, the second capacitor unit, the third capacitor unit, the fourth capacitor unit, the fifth capacitor unit and the sixth capacitor unit are connected in series;

the first end of the first capacitor unit is connected to a connection point of the first auxiliary switch and the Nth auxiliary switch, the first end of the Mth capacitor unit is connected to a connection point of the M-1 th auxiliary switch and the Mth auxiliary switch, and M is a positive integer of 2-N;

second ends of the first to Nth capacitor units are connected with each other;

In some embodiments, the apparatus further includes a controller for controlling the first to nth auxiliary switches, the first access switch, the second access switch, the third access switch, and each of the switching units.

According to the embodiment of the invention, the size of the accessed capacitor can be changed by adjusting the closing state of the auxiliary switch and the closing states of the three access switches through the structure of the device.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a circular capacitor array reactive power compensation device according to an embodiment of the present invention;

fig. 2 is a schematic application diagram of a circular capacitor array reactive power compensation device provided by an embodiment of the present invention;

fig. 3 is a schematic diagram of an alternative compensation mode in a large capacitance compensation mode of the circular capacitor array reactive compensation device provided by the embodiment of the invention;

FIG. 4 is a schematic diagram of a 1C tolerant compensation path according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a 2C compensation path according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a 3C compensation path according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of a 4C compensation path according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a 5C capacity compensation path according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of a 6C capacity compensation path according to an embodiment of the present invention;

FIG. 10 is a schematic diagram of a compensation path with a capacitance of 7C according to an embodiment of the present invention;

FIG. 11 is a schematic diagram of an 8C compensation path according to an embodiment of the present invention;

fig. 12 is a schematic diagram illustrating an alternative compensation manner in a small capacitance value compensation mode of the circular capacitor array reactive power compensation device according to the embodiment of the present invention;

FIG. 13 is a schematic diagram of a C/2 capacity compensation path according to an embodiment of the present invention;

FIG. 14 is a schematic diagram of a 2C/3 capacity compensation path according to an embodiment of the present invention;

FIG. 15 is a schematic diagram of a 3C/4 capacity compensation path according to an embodiment of the present invention;

FIG. 16 is a schematic diagram of a 4C/5 capacity compensation path according to an embodiment of the present invention;

FIG. 17 is a schematic diagram of a 5C/6 capacity compensation path according to an embodiment of the present invention;

FIG. 18 is a schematic diagram of a compensation path with a capacitance of 6C/7 according to an embodiment of the present invention;

FIG. 19 is a schematic diagram of a compensation path with a capacitance of 7C/8 according to an embodiment of the present invention;

FIG. 20 is a diagram of a C-tolerant compensation path according to an embodiment of the present invention;

FIG. 21 is a schematic diagram of a compensation path with a capacitance of 6C/5 according to an embodiment of the present invention;

FIG. 22 is a schematic diagram of a 4C/3 capacity compensation path according to an embodiment of the present invention;

FIG. 23 is a schematic diagram of a compensation path with a capacitance of 10C/7 according to an embodiment of the present invention;

FIG. 24 is a schematic diagram of a 3C/2 capacity compensation path according to an embodiment of the present invention;

FIG. 25 is a schematic diagram of another compensation path with a capacitance of 3C/2 according to an embodiment of the present invention;

FIG. 26 is a schematic diagram of a 12C/7 capacity compensation path according to an embodiment of the present invention;

FIG. 27 is a schematic diagram of a 15C/8 capacity compensation path according to an embodiment of the present invention;

fig. 28 is a schematic diagram of a 2C-tolerant compensation path according to an embodiment of the present invention.

Detailed Description

In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be clearly and completely described below through embodiments with reference to the accompanying 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. 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.

This patent provides a circular capacitor array reactive power compensator, and the device can be according to actual conditions needs selecting appropriate capacitance value and carrying out series-parallel connection and star, triangular connection to utilize limited electric capacity collocation to go out the equivalent capacitance that the impedance value is different, and then reach and compensate comparatively accurately to idle. Although the change of the reactive power demand cannot be tracked, namely the dynamic compensation of the reactive power cannot be realized, the reactive power compensation continuous curve is divided into steps for compensation, the thinner the step division is, the more the segments are, the higher the precision of the reactive power compensation is, and thus the actual demand can be met.

Referring to fig. 2, the present embodiment discloses a circular capacitor array reactive power compensation device, which can be applied in the ac input scenario shown in fig. 2, and the device includes: the first auxiliary switch a1, the second auxiliary switch a2, the third auxiliary switch A3, the fourth auxiliary switch A4, the fifth auxiliary switch a5, the sixth auxiliary switch A6, the seventh auxiliary switch A7, the eighth auxiliary switch a8, the first capacitor unit (including the first capacitor C1 and the first switch a1), the second capacitor unit (including the second capacitor C2 and the second switch a2), the third capacitor unit (including the third capacitor C3 and the third switch A3), the fourth capacitor unit (including the fourth capacitor C4 and the fourth switch A4), the fifth capacitor unit (including the fifth capacitor C5 and the fifth switch a5), the sixth capacitor unit (including the sixth capacitor C6 and the sixth switch A6), the seventh capacitor unit (including the seventh capacitor C7 and the seventh switch A7), and the eighth capacitor unit (including the eighth switch C8 and the eighth switch S3687458), and the first capacitor unit (including the first switch C4 and the fourth switch a8), the second switch a8, the third switch a8, the second switch a 3628, the third switch a8, the second switch a, the third switch a, the second switch b 8, the third switch b, the second switch b, the third switch b, the second switch b, the third switch, the second switch, the third switch, the second switch, the third switch, the second switch, the third switch, the second switch, the third switch, the second switch, the third switch, the, A second access switch S2 and a third access switch S3;

the first auxiliary switch a1, the second auxiliary switch a2, the third auxiliary switch A3, the fourth auxiliary switch a4, the fifth auxiliary switch a5, the sixth auxiliary switch a6, the seventh auxiliary switch a7, and the eighth auxiliary switch A8 are sequentially connected in series in a ring shape;

the first capacitor unit, the second capacitor unit, the third capacitor unit, the fourth capacitor unit, the fifth capacitor unit, the sixth capacitor unit, the seventh capacitor unit and the eighth capacitor unit are all formed by serially connecting a capacitor and a fling-cut switch;

a first end of the first capacitor unit is connected to a connection point of the first auxiliary switch a1 and an eighth auxiliary switch A8, a first end of the second capacitor unit is connected to a connection point of the first auxiliary switch a1 and the second auxiliary switch a2, a first end of the third capacitor unit is connected to a connection point of the second auxiliary switch a2 and the third auxiliary switch A3, a first end of the fourth capacitor unit is connected to a connection point of the third auxiliary switch A3 and the fourth auxiliary switch a4, a first end of the fifth capacitor unit is connected to a connection point of the fourth auxiliary switch a4 and the fifth auxiliary switch a5, a first end of the sixth capacitor unit is connected to a connection point of the fifth auxiliary switch a5 and the sixth auxiliary switch A6, and a first end of the seventh capacitor unit is connected to a connection point of the sixth auxiliary switch A6 and the seventh auxiliary switch a7, a first end of the eighth capacitor unit is connected to a connection point of the seventh auxiliary switch a7 and an eighth auxiliary switch A8;

In some embodiments, the capacitance values of the capacitors are the same and are all C.

Based on the above structure, the device has two output ports (i.e. two access ports), wherein the port a is connected to the first access switch S1, the other end of the first access switch S1 is connected to the upper node, the position of the node is changeable, and there are eight positions to be selected in total. The other port B is connected to the second switch S2 and the second switch S3 through an inductor with a very small inductance value, the inductor is mainly used to suppress the rush current generated when the capacitor is connected to the circuit, the second switch S3 can be connected to any edge node of the circle, and the second switch S2 is mainly connected to the center node of the circle. The second access switch S2 and the third access switch S3 cannot be switched on simultaneously, and the switching on of the access switches is different, which also determines the different operation modes of the whole capacitor array.

The compensation function is realized by mainly closing the auxiliary switches A1-A8, the first access switch S1, the second access switch S2 and the third access switch S3, connecting a plurality of capacitors in series and parallel, combining different capacitor capacity specifications by using series and parallel connection and star-shaped triangular connection, and further determining the capacity of the capacitor which is put into a system according to the reactive power requirement of the power grid to be compensated, so that the capacitor with proper size is selected to be connected, and further dynamic compensation of reactive power is realized. The closing of the access switch determines the working mode of the capacitance reactive compensation array, and the closing of the first access switch S1 and the second access switch S2 mainly performs capacitance doubling compensation, so that the mode is mainly used for meeting the reactive power compensation mode with a larger value. The closing of the second access switch S2 and the third access switch S3 mainly achieves a small value of reactive compensation. For convenience of description, the first to eighth auxiliary switches are denoted by a1 to A8, the first access switch is denoted by S1, the second access switch is denoted by S2, the third access switch is denoted by S3, the first to eighth capacitors are denoted by C1 to C8, the connection points of C1 to C8 are denoted by 0, and the switch switches corresponding to C1 to C8 are denoted by a1 to A8.

The working principle of the present invention is explained as follows:

due to the symmetry of the circuit diagram, the paths implemented are different because the selected points are different, and therefore the equivalent capacitance values are analyzed by way of example of the paths. The circuit model is simplified for ease of description. The active terminals of switch S1 and switch S3 are connected to and held in place by edge nodes a1 and a2, respectively. A series-parallel connection selection method of the capacitor at the A end comprises the following steps: the selection is made in the clockwise direction. The capacitor series-parallel connection selection rule of the terminal B is as follows: the selection is performed in a counter-clockwise direction. The two sub-capacitor modules respectively select different numbers of capacitors to be connected in parallel, and then the two sub-modules are connected in series to obtain a finer capacitance value.

Large value compensation mode:

when the access switch S1/S2 is closed, the reactive compensation unit mainly performs capacitance doubling compensation. At this time, the port a and the port B only need to select one end as an output end. According to the reactive compensation required in practice, firstly, a proper reactive compensation space is determined, and then the capacitance capacity of C-8C can be obtained by closing the auxiliary switches A1-A8 in relative quantity, and the optional capacitance condition is shown in figure 3. For convenience of description, the a port is used as the output terminal, and the auxiliary switches are sequentially closed in the order of a1 to A8.

Referring to fig. 4, when only the auxiliary switch a1 is closed, only the capacitor (e.g., C1) is connected to the circuit, and the system performs reactive compensation for C.

Referring to fig. 5, when the auxiliary switches a1 and a2 are closed, two capacitors (C1 and C2) are connected in parallel to the circuit, and the system performs 2C reactive power compensation.

Referring to fig. 6, when the auxiliary switches a1, a2 and A3 are closed, three capacitors (C1, C2 and C3) are connected into the circuit, and the system performs 3C reactive compensation.

Referring to fig. 7, when the auxiliary switches a1, a2, A3 and a4 are closed, four capacitors (C1, C2, C3 and C4) are connected into the circuit, and the system performs 4C reactive power compensation.

Referring to fig. 8, when the auxiliary switches a1, a2, A3, a4 and a5 are closed, five capacitors (C1, C2, C3, C4 and C5) are connected to the circuit, and the system performs 5C reactive compensation.

Referring to fig. 9, when the auxiliary switches a1, a2, A3, a4, a5 and a6 are closed, six capacitors (e.g., C1, C2, C3, C4, C5 and C6) are connected to the circuit at this time, and the system performs reactive power compensation of 6C.

Referring to fig. 10, when the auxiliary switches a1, a2, A3, a4, a5, a6 and a7 are closed, seven capacitors (e.g., C1, C2, C3, C4, C5, C6 and C7) are connected to the circuit, and the system performs reactive compensation of 7C.

Referring to fig. 11, when all the auxiliary switches are closed, all the capacitors are connected into the circuit at this time, and the system performs reactive compensation of 8C.

Table 1 shows all the optional capacitance values.

TABLE 1

Decimal compensation mode:

the following is a second operation mode of the novel capacitor array of this embodiment: referring to fig. 12, the interval of 0-2C is divided into 15 segments in this embodiment. And the subarea interval is thinned, so that the compensation precision of the capacitor array can be greatly improved, and the dynamic characteristic of the reactive power compensation of the capacitor is improved. For convenience of explanation of the operating principle of the circuit. The capacitance connected with the terminal A is selected from C1-C8-C7-C6-C5-C4-C3-C2-C1 in sequence. The capacitors directly connected with the terminal B are sequentially connected from C2-C3-C4-C5-C6-C7-C8-C1-C2.

As shown in FIG. 13, when the access switches S1 and S3 are closed and no auxiliary switch is accessed, two capacitors C1 and C2 are connected in series to the circuit, the equivalent value of the capacitor array is C/2, and the system performs C/2 reactive compensation.

Referring to fig. 14, when the access switches S1 and S3 are closed and only the auxiliary switch a2 is connected into the circuit, there are 3 capacitors connected into the circuit, wherein C2C3 is connected in parallel and then connected into the circuit in series with C1, the equivalent capacitance of the capacitor array is 2C/3, and the system performs 2C/3 reactive compensation.

Referring to fig. 15, when the access switches S1 and S3 are closed and the auxiliary switches a2 and A3 are connected into the circuit, there are 4 capacitors connected into the circuit, wherein C2, C3 and C4 are connected in parallel and then connected into the circuit in series with C1, the equivalent capacitance of the capacitor array is 3C/4, and the system performs 3C/4 reactive compensation.

Referring to fig. 16, when the access switches S1 and S3 are closed and only the auxiliary switches a2, A3 and a4 are connected to the circuit, there are 5 capacitors connected to the circuit, wherein C2, C3, C4 and C5 are connected in parallel and then connected to the circuit in series with C1, and at this time, the equivalent capacitance of the capacitor array is 4C/5, and the system performs 4C/5 reactive compensation.

Referring to fig. 17, when the access switches S1 and S3 are closed and only the auxiliary switches a2, A3, a4 and a5 are connected to the circuit, there are 6 capacitors connected to the circuit, where C2, C3, C4, C5 and C6 are connected in parallel and then connected in series with C1 to the circuit, and at this time, the equivalent capacitance of the capacitor array is 5C/6, and the system performs 5C/6 reactive compensation.

Referring to fig. 18, when the access switches S1 and S3 are closed and only the auxiliary switches a2, A3, a4, a5 and a6 are connected to the circuit, there are 7 capacitors connected to the circuit, where C2, C3, C4, C5, C6 and C7 are connected in parallel and then connected in series with C1 to the circuit, and the equivalent capacitance of the capacitor array is 6C/7, and the system performs 6C/7 reactive compensation.

Referring to fig. 19, when the access switches S1 and S3 are closed, and only the auxiliary switches a2, A3, a4, a5, a6 and a7 are connected into the circuit, at this time, 8 capacitors are connected into the circuit, wherein C2, C3, C4, C5, C6, C7 and C8 are connected in parallel and then connected into the circuit in series with C1, at this time, the equivalent capacitance of the capacitor array is 7C/8, and the system performs reactive compensation of 7C/8.

Referring to fig. 20, when the access switches S1 and S3 are closed and only the auxiliary switches a8 and a2 are connected to the circuit, there are 4 capacitor access circuits at this time, where C2 and C3 are connected in parallel two by two to form a first capacitor sub-module, C1 and C8 are connected in parallel two by two to form a second capacitor sub-module, the two capacitor sub-modules are connected in series to the circuit again, the equivalent capacitance of the capacitor array is C at this time, and the system performs capacitance compensation of C.

Referring to fig. 21, when the access switches S1 and S3 are closed and only the auxiliary switches a8, a2 and A3 are connected to the circuit, there are 5 capacitors connected to the circuit, wherein the first capacitor sub-module is formed by connecting C2, C3 and C4 in parallel and the second capacitor sub-module is formed by connecting C1 and C8 in parallel, then the two capacitor sub-modules are connected to the circuit in series, the equivalent capacitance of the capacitor array is 6C/5, and the system performs 6C/5 reactive compensation.

Referring to fig. 22, when the access switches S1 and S3 are closed and only the auxiliary switches a8, a2, A3 and a4 are connected into the circuit, there are 6 capacitors connected into the circuit, where C2, C3, C4 and C5 are connected in parallel to form a first capacitor sub-module, C1 and C8 are connected in parallel to form a second capacitor sub-module, the two capacitors are connected into the circuit in series, the equivalent capacitance of the capacitor array is 4C/3, and the system performs 4C/3 reactive power compensation.

Referring to fig. 23, when the access switches S1 and S3 are closed and only the auxiliary switches A8, a2, A3, a4 and a5 are connected into the circuit, there are 7 capacitors connected into the circuit at this time, where C2, C3, C4, C5 and C6 are connected in parallel to form a first capacitor sub-module, C1 and C8 are connected in parallel to form a second capacitor sub-module, and then connected into the circuit in series, where the equivalent capacitance of the capacitor array is 10C/7, and the system performs 10C/7 reactive compensation.

Referring to fig. 24, when the access switches S1 and S3 are closed and only the auxiliary switches A8, a2, A3, a4, a5 and a6 access the circuit, there are 8 capacitors access the circuit, where C2, C3, C4, C5, C6 and C7 are connected in parallel to form a first capacitor sub-module, and C1 and C8 are connected in parallel to form a second capacitor sub-module and then connected in series to the circuit. At the moment, the equivalent capacitance of the capacitor array is 3C/2, and the system carries out 3C/2 reactive compensation.

Referring to fig. 25, when the access switches S1 and S3 are closed and only the auxiliary switches a8, a7 and a2 are connected to the circuit, there are 6 capacitors connected to the circuit, wherein C2, C3 and C4 are connected in parallel to form a first capacitor sub-module, and C1, C8 and C7 are connected in parallel to form a second capacitor sub-module, and then connected to the circuit in series, at this time, the equivalent capacitance of the capacitor array is also 3C/2, and the system performs 3C/2 reactive power compensation.

Referring to fig. 26, when the access switches S1 and S3 are closed and only the auxiliary switches A8, a7, a2, A3 and a4 are connected to the circuit, there are 7 capacitors connected to the circuit at this time, where C2, C3, C4 and C5 are connected in parallel to form a first capacitor sub-module, C1, C8 and C7 are connected in parallel to form a second capacitor sub-module, and then connected to the circuit in series, the equivalent capacitance of the capacitor array is 12C/7 at this time, and the system performs 12C/7 reactive compensation.

Referring to fig. 27, when the access switches S1 and S3 are closed and only the auxiliary switches A8, a7, a2, A3, a4 and a5 are connected into the circuit, there are 8 capacitors connected into the circuit, where C2, C3, C4, C5 and C6 are connected in parallel to form a first capacitor sub-module, C1, C8 and C7 are connected in parallel to form a second capacitor sub-module, and then the capacitors are connected into the circuit in series, at this time, the equivalent capacitance of the capacitor array is 15C/8, and the system performs reactive compensation of 15C/8.

Referring to fig. 28, when the access switches S1 and S3 are closed, and only the auxiliary switches A8, a7, a6, a2, A3, and a4 are connected into the circuit, there are 8 capacitors connected into the circuit at this time, where C2, C3, C4, and C5 are connected in parallel to form a first capacitor sub-module, C1, C8, C7, and C6 are connected in parallel to form a second capacitor sub-module, and then connected into the circuit in series, where the equivalent capacitance of the capacitor array is 2C, and the system performs 2C capacitance compensation. Table 2 shows all adjustable capacitance values.

TABLE 2

C/2

2C/3

3C/4

4C/5

5C/6

6C/7

7C/8

C

6C/5

8C/6

10C/7

3C/2

12C/7

15C/8

2C

The embodiment discloses a circular capacitor array reactive power compensator, includes: the first to Nth auxiliary switches, the first to Nth capacitance units, the first access switch, the second access switch and the third access switch, wherein N is a positive integer which is more than or equal to three and not equal to eight;

second ends of the first to Nth capacitor units are connected with each other;

In the structure shown in fig. 1, N is 8, and it is considered that N is other than 8 in the present embodiment, and the embodiments can also achieve the above technical effects.

The advantages of the above embodiments are discussed:

because the current thyristor switched capacitor belongs to a fixed capacitor, and the combined use of the fixed capacitor can only be matched with a plurality of fixed numerical values for reactive compensation of a system. Because the compensation mechanism naturally has certain defects, the limited numerical value is determined by the limited collocation mode, so that the compensation precision is seriously influenced, and the dynamic performance is greatly reduced. Therefore, this patent has proposed a novel capacitor array reactive compensation mode, and the purpose is exactly to utilize the limited fixed capacitance value of figure, and as far as possible the collocation goes out diversified electric capacity combination scheme. The purpose of this is to divide an interval into several small intervals reasonably, select a suitable value in each small interval, and use a straight line with a suitable value to replace the corresponding curve approximately, which is the idea of changing the curve into straight one commonly used in mathematics. With the thinner interval division, a straight line can be approximately regarded as a curve. The method utilizes the limited capacitance value to carry out diversified permutation and combination, thereby not only enriching the flexibility of the use of the system, but also greatly improving the compensation precision and the dynamic characteristic of the traditional capacitor bank, and simultaneously, the control operation mode is very convenient. The simple and reliable circuit design reduces the manufacturing cost of the whole system and creates great advantages for the large-scale application of the system. Meanwhile, the symmetry of the circuit structure is not fixed, and the capacitor can be randomly selected, so that the repeated use of one capacitor is greatly avoided, and the method has a far-reaching significance for prolonging the application value of the whole system.

The novel capacitor array reactive power compensation device disclosed in the above embodiment has 15 compensation modes in a small numerical value compensation mode, and 8 compensation modes in a large numerical value compensation mode. When the capacitance quantity of the circular system is increased, the output scheme of the system can be greatly enriched, and the integral reactive power regulation precision is effectively improved.

For the same reactive output, the capacitor array has multiple working modes, for example, in a large-numerical compensation mode, reactive compensation of C capacitor with multiple times is required, the reactive compensation can be obtained only by correspondingly closing a certain number of auxiliary switches, and random selection can be performed when the auxiliary switches are closed, so that the flexibility of the system is greatly improved, and the fault tolerance rate of the system is improved. If a plurality of capacitors of the system are damaged, other capacitors can be selected for replacement. The diversity selection of the capacitor correspondingly avoids the condition that a single capacitor is put into operation for a long time, thereby greatly prolonging the service life of the capacitor of the whole system; meanwhile, the flexible working mode also improves the reliability of the capacitor array compensation, and when a certain capacitor branch is damaged, the overall compensation of the capacitor array is not greatly influenced.

This patent capacitor array's output state switches realizes through control switch's closure, and control is simple, convenient, can realize reactive power's the compensation of the quick degree of depth, and the abundant variety of dynamic property that has improved whole capacitor array in the numerical value.

This patent adopts the curved thought of changing into straight, and the thought that we intend to adopt is in order to reduce the frequent access of reactive capacitor array for continuous reactive change curve originally, divides it into suitable interval, and we substitute corresponding curve with a straight line approximation in every interval. In a proper interval, we select the value closest to the value, thus greatly reducing the frequency of the switch-in circuit of the switch and prolonging the service life of the capacitor array.

The condenser has adopted neotype topological connected mode, through the access mode of controlling different electric capacity, changes the series-parallel combination mode of capacitor bank, lets the limited electric capacity of original quantity, carries out orderly combination, constructs out the capacitance value that numerical value is different, increases its equivalent output capacitance's selection, has improved entire system's flexibility greatly, has optimized the idle precision of the cascaded compensation of capacitor bank, has improved the reactive compensation performance of capacitor bank.

Novel capacitor array has multiple combination series-parallel connection mode, has improved the flexibility of chooseing for use greatly, and reactive output can adopt different connected mode simultaneously, and capacitor array has more nimble regulating power. These flexible adjustment capabilities also greatly improve the practical applicability of the system. The novel flexible configuration mode of the capacitor array can effectively improve the operation safety and reliability of the capacitor bank. When part of the capacitor bank in the capacitor array is damaged, the capacitor array can still work normally by replacing the access mode.

The device has simple circuit topological structure, lower manufacturing cost and fewer manufacturing procedures, is suitable for large-scale industrial manufacturing, can be applied and popularized on a large scale in the industry due to the advantage of low cost, and has simple control mode. Under the condition of not increasing the capacitor bank, the reactive compensation precision of the capacitor bank can be optimized through simple control, the reactive compensation effect on a power grid can be improved, and the method has strong popularization and practical application values.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present application and the technical principles employed. It will be understood by those skilled in the art that the present application is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the application. Therefore, although the present application has been described in more detail with reference to the above embodiments, the present application is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A circular capacitor array reactive power compensation device, characterized by comprising: the first auxiliary switch, the second auxiliary switch, the third auxiliary switch, the fourth auxiliary switch, the fifth auxiliary switch, the sixth auxiliary switch, the seventh auxiliary switch, the eighth auxiliary switch, the first capacitor unit, the second capacitor unit, the third capacitor unit, the fourth capacitor unit, the fifth capacitor unit, the sixth capacitor unit, the seventh capacitor unit, the eighth capacitor unit, the first access switch, the second access switch and the third access switch;

2. The circular capacitor array reactive power compensation device of claim 1, wherein an access inductor is further connected to the second access point.

3. The circular capacitor array reactive power compensation device of claim 1, wherein each switching unit is formed by connecting two thyristors in opposite directions in parallel.

4. The circular capacitor array reactive power compensation device of claim 1, wherein the capacitance values of the capacitors are the same.

5. The circular capacitor array reactive power compensation device as claimed in claim 3, further comprising a controller for controlling the first auxiliary switch, the second auxiliary switch, the third auxiliary switch, the fourth auxiliary switch, the fifth auxiliary switch, the sixth auxiliary switch, the seventh auxiliary switch, the eighth auxiliary switch, the first access switch, the second access switch, the third access switch and each of the switching units.

6. The circular capacitor array reactive power compensation device of claim 5, wherein the controller controls each switching unit based on a power grid power frequency, so that two thyristors in the switching unit are alternately conducted along with the power grid power frequency.

7. A circular capacitor array reactive power compensation device, characterized by comprising: the first to Nth auxiliary switches, the first to Nth capacitance units, the first access switch, the second access switch and the third access switch, wherein N is a positive integer which is more than or equal to three and not equal to eight;

second ends of the first to Nth capacitor units are connected with each other;

8. The circular capacitor array reactive power compensation device of claim 7, wherein each switching unit is formed by connecting two thyristors in opposite directions in parallel.

9. The circular capacitor array reactive power compensation device as claimed in claim 8, further comprising a controller for controlling the first to nth auxiliary switches, the first access switch, the second access switch, the third access switch and each of the switching units.

10. The circular capacitor array reactive power compensation device of claim 9, wherein the controller controls each switching unit based on a power grid power frequency, so that two thyristors in the switching unit are alternately conducted along with the power grid power frequency.