WO2023087435A1

WO2023087435A1 - Improved grounding transformer doubling as station transformer

Info

Publication number: WO2023087435A1
Application number: PCT/CN2021/136751
Authority: WO
Inventors: 盛建科; 盛亮科; 詹柏青; 罗万里; 李小锋; 刘湘; 王正云
Original assignee: 广东福德电子有限公司; 株洲福德轨道交通研究院有限公司; 湖南福德电气有限公司
Priority date: 2021-11-19
Filing date: 2021-12-09
Publication date: 2023-05-25
Also published as: CN114068156A

Abstract

The present invention relates to an improved grounding transformer doubling as a station transformer, comprising: a grounding transformer secondary side; and a grounding transformer primary side comprising six primary side windings A1, A2, B1, B2, C1, and C2 that are wound on a three-phase core. Two of the primary side windings are distributed on each core column of the three-phase core, and the two primary side windings have an equal number of turns; the six primary side windings are wired in a Z-connection mode; the topological structure of the grounding transformer secondary side and the topological structure of the grounding transformer primary side are the same and are symmetrical to each other. According to the present invention, formulas I, II, and III of low-voltage output phase voltage vectors can successively be in phase with formulas IV, V, and VI of phase voltage vectors of high-voltage input side power grid voltage, respectively.

Description

An Improved Grounding Transformer Doubling as Substation Transformer

technical field

The invention relates to the field of transformers, in particular to an improved grounding transformer which doubles as a substation transformer.

Background technique

The circuit topology of the traditional grounding transformer that doubles as a substation transformer is shown in patent document 201710544978.8, which is the structure in Figure 1.

The grounding transformer of this structure doubles as a substation transformer. There is only one winding on the secondary side of each core column. The output phase voltage and the phase voltage vector of the primary side will differ by 30 degrees in electrical angle, which cannot reach the low-voltage output phase voltage vector.

The phase voltage vector of the grid voltage on the high voltage input side

in phase with each other.

technical problem

The phase voltage vector of the grid voltage on the high voltage input side

in phase with each other.

technical solution

The invention provides an improved grounding transformer which doubles as a substation transformer, which can achieve low-voltage output phase voltage vector

The phase voltage vector of the grid voltage on the high voltage input side

in phase with each other.

In order to achieve the above purpose, according to one aspect of the present invention, an improved grounding transformer that doubles as a substation transformer is provided, including:

Secondary side of grounding transformer;

The primary side of the grounding transformer has six primary side windings A1, A2, B1, B2, C1, and C2 wound on the three-phase iron core, wherein two of the primary side windings are distributed on each core leg of the three-phase iron core, And the number of turns of the two primary side windings is equal;

The six primary side windings are connected in a Z-type connection;

The topological structure of the secondary side of the grounding transformer is the same as that of the primary side of the grounding transformer, and the two are symmetrical to each other.

As an improvement, the wiring method of the primary side of the grounding transformer further includes:

The end of the primary winding A1 is connected to the end of the primary winding C2;

The end of the primary side winding B1 is connected to the end of the primary side winding A2;

The end of the primary side winding C1 is connected to the end of the primary side winding B2;

The first ends of the primary side windings A2, B2, and C2 are connected to form a neutral point N of the ground transformer;

The first ends of the primary side windings A1, B1, and C1 are connected to the three-phase distribution network;

Among them, the end with the same name is the first end of the winding, and the other end is the end of the winding.

The neutral point N is grounded through an arc suppressing coil.

As an improvement, the secondary side of the grounding transformer has six secondary side windings A3, A4, B3, B4, C3, and C4 wound on the three-phase iron core, wherein each iron core column of the three-phase iron core Distributing two secondary side windings, and the number of turns of the two secondary side windings is equal;

The six secondary side windings are also connected in a Z-connection manner.

As an improvement, the wiring method of the secondary side of the grounding transformer further includes:

The end of the secondary winding A4 is connected to the end of the secondary winding C3;

The end of the secondary winding B4 is connected to the end of the secondary winding A3;

The end of the secondary winding C4 is connected to the end of the secondary winding B3;

The first ends of the secondary side windings A3, B3, and C3 are connected to form a neutral point n of the ground transformer;

The first ends of the secondary side windings A4, B4, and C4 serve as low-voltage three-phase output ends.

As an improvement, the number of turns Np of each primary side winding is equal, and

The number of turns Ns of each secondary winding is equal.

The description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious It is easy to understand that the specific embodiments of the present invention are given below.

Beneficial effect

The improved grounding transformer which also serves as a substation transformer provided by the present invention is improved on the basis of the traditional grounding transformer, and can realize low-voltage output phase voltage vector

The phase voltage vector of the grid voltage on the high voltage input side

in phase with each other.

Description of drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiment. The drawings are only for the purpose of illustrating a preferred embodiment and are not to be considered as limiting the invention. Also throughout the drawings, the same stage is denoted by the same reference numeral.

In the attached picture:

Figure 1 is a circuit topology diagram of an improved grounding transformer that doubles as a traditional substation transformer;

Fig. 2 is the structure schematic diagram of the improved grounding transformer double as the substation of the present invention;

Fig. 3 is the circuit topological diagram of the improved grounding transformer which doubles as a substation transformer of the present invention.

Embodiments of the present invention

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided for more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

Referring to Fig. 2, it is a structural schematic diagram of the improved grounding transformer which doubles as a substation transformer in this embodiment. Its circuit topology is shown in Fig. 3, including a three-phase iron core, a secondary side of the grounding transformer, and a primary side of the grounding transformer.

The primary side of the grounding transformer is set to be composed of six primary side windings A1, A2, B1, B2, C1, and C2 wound on a three-phase iron core in order to lead out the neutral point N of the distribution network, wherein the three-phase Two primary side windings are distributed on each core column of the iron core, and the number of turns of the two primary side windings is equal. For example, the primary side of the A-phase core legs of the three-phase core is distributed A1, A2 from top to bottom, and the number of turns of A1 and A2 is equal. Similarly, the B-phase core legs are distributed with B1 and B2, and the C-phase core legs are distributed with C1 and C2.

After such distribution, the reverse polarity of the primary side windings A1, A2, B1, B2, C1, and C2 are connected in series to form a star winding, that is, the wiring is performed in a Z-connection manner. Specifically, the wiring method of the primary side of the grounding transformer is further Set as:

The first ends of the primary side windings A1, B1 and C1 are connected to the three-phase power distribution network.

In Fig. 3, the origin next to the winding is used to represent the end with the same name, and the end with the same name is the first end of the winding, and the other end is called the end.

In this embodiment, in order to eliminate the 30-degree electrical angle difference between the output phase voltage and the phase voltage vector of the primary side, the topological structure of the secondary side of the grounding transformer is set to be the same as that of the primary side of the grounding transformer, and the two are symmetrical to each other .

Specifically, the secondary side of the grounding transformer is composed of six secondary side windings A3, A4, B3, B4, C3, and C4 wound on a three-phase iron core, where two The above-mentioned secondary side windings, and the number of turns of the two secondary side windings is equal. For example, the secondary side of the A-phase core leg of the three-phase core is distributed A3, A4 from top to bottom, and the number of turns of A3 and A4 is equal. Similarly, the B-phase core leg is distributed with B3 and B4, and the C-phase core leg is distributed with C3 and C4.

For the secondary side of the grounding transformer, A3, A4, B3, B4, C3, and C4 are also connected in series in reverse polarity to form a star winding, that is, the wiring is performed in a Z-connection manner. Specifically, the wiring on the secondary side of the grounding transformer The method is further set to:

The improved grounding transformer that doubles as a substation transformer provided in this embodiment is improved on the basis of the traditional grounding transformer, and can realize low-voltage output phase voltage vector

The phase voltage vector of the grid voltage on the high voltage input side

in phase with each other.

As an optional implementation, the connection mode of the primary side of the grounding transformer is further set such that the neutral point N is grounded through an arc suppressing coil, which is used to compensate most of the capacitive reactive power flowing through the ground fault point. current.

As another optional implementation mode, in the setting of the number of turns, the number of turns Np of each of the primary side windings is set to be equal, and the number of turns of each of the secondary side windings Ns is equal, so that the station provided by this embodiment also serves as a station. The modified improved grounding transformer forms a fully symmetrical structure, which can improve the reliability and stability of the grounding transformer.

In this optional embodiment, the number of turns of each winding on the primary side is Np, the number of turns on the low-voltage output side is Ns, and the turns ratio k=Np/Ns, according to the wiring in Figure 2 and Figure 3 and the relationship between the same name end of the winding , ignoring the influence of leakage inductance, the following vector relationship can be obtained:

That is, the output phase voltage of the secondary side corresponds to the same phase as that of the primary side, and its amplitude is 1/k times that of the corresponding phase of the primary side.

It should be noted that the embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a unit claim enumerating several means, several of these means can be embodied by one and the same item of hardware. The use of the words first, second, and third, etc. does not indicate any order. These words can be interpreted as names.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure the understanding of this description.

Claims

An improved grounding transformer double as a substation transformer, including:

Secondary side of grounding transformer;

The primary side of the grounding transformer has six primary side windings A1, A2, B1, B2, C1, and C2 wound on the three-phase iron core, wherein two of the primary side windings are distributed on each core leg of the three-phase iron core, And the number of turns of the two primary side windings is equal;

It is characterized by:

The six primary side windings are connected in a Z-type connection;

The topological structure of the secondary side of the grounding transformer is the same as that of the primary side of the grounding transformer, and the two are symmetrical to each other.
The improved grounding transformer double as a substation transformer according to claim 1, wherein the connection mode of the primary side of the grounding transformer further comprises:

The end of the primary winding A1 is connected to the end of the primary winding C2;

The end of the primary side winding B1 is connected to the end of the primary side winding A2;

The end of the primary side winding C1 is connected to the end of the primary side winding B2;

The first ends of the primary side windings A2, B2, and C2 are connected to form a neutral point N of the ground transformer;

The first ends of the primary side windings A1, B1, and C1 are connected to the three-phase distribution network;

Among them, the end with the same name is the first end of the winding, and the other end is the end of the winding.
The improved grounding transformer which doubles as a substation transformer according to claim 2, wherein the connection mode of the primary side of the grounding transformer further comprises:

The neutral point N is grounded through an arc suppressing coil.
The improved grounding transformer which doubles as a substation transformer according to claim 2 is characterized in that,

The secondary side of the grounding transformer has six secondary side windings A3, A4, B3, B4, C3, and C4 wound on the three-phase iron core, wherein two of the two secondary windings are distributed on each iron core column of the three-phase iron core. secondary windings, and the number of turns of the two secondary windings is equal;

The six secondary side windings are also connected in a Z-connection manner.
The improved grounding transformer double as a substation transformer according to claim 4, characterized in that, the connection mode of the secondary side of the grounding transformer further comprises:

The end of the secondary winding A4 is connected to the end of the secondary winding C3;

The end of the secondary winding B4 is connected to the end of the secondary winding A3;

The end of the secondary winding C4 is connected to the end of the secondary winding B3;

The first ends of the secondary side windings A3, B3, and C3 are connected to form a neutral point n of the ground transformer;

The first ends of the secondary side windings A4, B4, and C4 serve as low-voltage three-phase output ends.
The improved grounding transformer which doubles as a substation transformer according to claim 4 is characterized in that,

the number of turns Np of each said primary winding is equal, and

The number of turns Ns of each secondary winding is equal.