JPH0645320U - Voltage regulator with built-in transformer - Google Patents

Abstract

(57) [Abstract] [Purpose] In a tap changer during load, it is possible to switch the taps without contact and to increase the number of tap stages. [Configuration] The primary winding of the main transformer and star connection, provided a voltage regulator 12 _U between the U-phase winding 11 _U and neutral point. The voltage regulator 12 _U includes a series transformer T ₁ and a parallel transformer T _1.
2 , the thyristor switches S _{11 to} S ₁₄ bridge-connected to the secondary winding T ₂₁ , the thyristor switches S _{21 to} S ₂₄ bridge-connected to the secondary winding T ₂₂ , and the secondary winding T ₂₃ . It is composed of thyristor switches S _{31 to} S ₃₄ connected in a bridge and thyristor switch S ₀ for overvoltage protection.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a secondary voltage adjusting method for a transformer, and more particularly to a voltage regulator with a built-in transformer.

[0002]

[Prior art]

 Conventionally, a tap regulator during load is configured to attach taps 2u, 2v, 2w to the primary windings 1u, 1v, 1w of a transformer as shown in Fig. 3 and to switch taps even during steady load power supply. Has been done.

[0003]

[Problems to be solved by the device]

 Since the conventional tap adjuster under load changes taps with contact points such as contacts, maintenance and inspection in consideration of wear is required.

The present invention has been made in view of the above points, and an object thereof is to provide a transformer-incorporated voltage regulator capable of switching the taps without contact and increasing the number of tap stages. Especially.

[0005]

[Means for Solving the Problems]

 (1) The primary winding of the main transformer is composed of a star connection, and a plurality of secondary windings having different turn ratios are provided in the electric path connecting each phase winding of the main transformer and the neutral point. A parallel transformer having a wire, a series transformer whose primary winding is connected to the primary winding of the parallel transformer, and each end of a plurality of secondary windings of the parallel transformer depending on the regulation voltage. And a voltage regulator composed of a semiconductor switch circuit that short-circuits and opens the semiconductor switch circuit, respectively. (2) The semiconductor switch circuit has a plurality of semiconductor switches bridge-connected to each other to form a plurality of bridge circuits. Of the common connection points of adjacent semiconductor switches of each of the bridge circuits, the first and second common connection points facing each other are respectively connected to the secondary windings of the parallel voltage transformer, and A plurality of bridge circuits are connected to each other among the common connection points. Via a fourth common connection point is characterized and this formed by connecting in series, it is characterized by comprising reverse parallel connection (3) the semiconductor switch thyristor.

[0006]

[Action]

 When both ends of the secondary winding of the parallel transformer are short-circuited by semiconductor switches, no voltage is induced in this secondary winding. Further, by opening both ends of the secondary winding with a semiconductor switch, a voltage corresponding to the turn ratio is induced in the secondary winding. The voltage e induced in the secondary winding of the parallel transformer is, for example, e when the secondary winding has three windings. ₁ = 4E / 7, e₂= 2E / 7, e₃Determine the winding ratio so that = 1E / 7 (where E is the voltage adjustment range). As a result, the voltage of the parallel transformer, that is, the voltage of the voltage regulator, is switched by changing the combination of ON and OFF of the semiconductor switch. Therefore, the taps on the primary winding of the main transformer will be switched equivalently.

Since the taps are switched by the semiconductor switch, contactless switching is possible, which facilitates maintenance and inspection. Also, the number of tap stages can be increased depending on the combined voltage of the parallel transformers.

[0008]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 11 in FIG._UIndicates the primary winding (U-phase winding) of the main transformer, and the primary winding is star-connected. Primary winding of main transformer 11_UVoltage regulator 12 between the neutral point and the neutral point_UIs connected. This voltage regulator 12_UIs the series transformer T₁And the primary winding is the series transformer T ₁ Connected to a plurality of secondary windings T_{twenty one}, T_{twenty two}, T_{twenty three}Parallel transformer T with₂And series transformer T₁Secondary winding and parallel transformer T₂And a secondary winding of the thyristor switch group SC1 connected thereto. The voltage regulator (12_U) Is also provided on the windings of the other phase on the primary side of the main transformer in the same manner as above.

The details of the thyristor switch group SC1 are configured as shown in FIG. In FIG. 2, S₁₁~ S₁₄, S_{twenty one}~ S_{twenty four}, S₃₁~ S₃₄Is a thyristor switch formed by connecting two thyristors in reverse parallel. Thyristor switch S₁₁~ S₁₄Are bridge-connected, and the common connection point a is a series transformer T₁Is connected to one end of the secondary winding. The common connection points b and c are parallel transformers T₂Secondary winding T_{twenty one}It is connected to the. Thyristor switch S_{twenty one}~ S_{twenty four}Are bridge-connected, and their common connection points d and e are parallel transformers T₂Secondary winding T_{twenty two}It is connected to the. Thyristor switch S₃₁ ~ S₃₄Are bridge-connected, and their common connection points f and g are parallel transformers T₂Secondary winding T_{twenty three}It is connected to the. The thyristor switch S₁₃, S₁₄The common connection point h is the thyristor switch S_{twenty one}, S_{twenty two}Connected to the common connection point i of the thyristor switch S _{twenty three} , S_{twenty four}Common connection point j of the thyristor switch S₃₁, S₃₂Connected to the common connection point k of. Thyristor switch S₃₃, S₃₄The common connection point l of the thyristor switch S is composed of two thyristors connected in anti-parallel.₀Through the series transformer T₁Is connected to the other end of the secondary winding.

Next, the operation of the apparatus configured as described above will be described. First, the thyristor switch S ₀ With the switch turned off, the thyristor switch S₁₁~ S₁₄, S_{twenty one}~ S_{twenty four}, S₃₁~ S_{3 Four} ON control, thyristor switch S₁₂, S₁₃Control off. Then the parallel transformer T₂The secondary winding of is T_{twenty two}, T_{twenty three}Is short-circuited and T_{twenty one}Only live. Therefore, the parallel transformer T₂Secondary voltage of e₁Will only be.

When the thyristor switches S ₁₁ , S ₁₄ , S ₂₁ , S ₂₄ , S _{31 to} S ₃₄ are on-controlled and the thyristor switches S ₁₂ , S ₁₃ , S ₂₂ , S ₂₃ are off-controlled, the parallel transformer T is turned on. _In the secondary winding of No. ₂ , T ₂₃ is short-circuited and T ₂₁ and T ₂₂ are activated. Therefore, the secondary voltage of the parallel transformer T ₂ becomes e ₁ + e ₂ .

Further, the thyristor switches S ₁₁ , S ₁₄ , S ₂₁ , S ₂₄ , S ₃₁ , and S ₃₄ are turned on, and the thyristor switches S ₁₂ , S ₁₃ , S ₂₂ , S ₂₃ , S ₃₂ , and S ₃₃ are turned off. Then, all the secondary windings of the parallel transformer T ₂ are activated, and the secondary voltage becomes e ₁ + e ₂ + e ₃ .

As described above, the secondary voltage of the parallel transformer T ₂ is changed by turning on / off any one of the thyristor switches S _{11 to} S ₁₄ , S _{21 to} S ₂₄ , and S _{31 to} S _34. Therefore, tap switching of the primary winding 11 _U of the main transformer is equivalently performed.

When an abnormality occurs in the device due to overvoltage, etc., the thyristor switch S ₀ Is turned on for protection.

By presetting the turns ratio of the secondary winding of the parallel transformer T ₂ , for example, the secondary voltages e ₁ , e ₂ , e ₃ are e ₁ = 4E / 7, e ₂ = 2E / 7, e ₃ = 1 · E / 7 (where E is the voltage adjustment range for 15 tap switching).

Table 1 below shows the relationship between the on / off combinations of the thyristor switches S _{11 to} S ₁₄ , S _{21 to} S ₂₄ , and S _{31 to} S ₃₄ and the taps.

[0017]

[Table 1]

The voltage regulator 12 _U is not limited to being provided inside the main transformer, but may be provided outside. Further, the semiconductor switch used in the present invention is not limited to the thyristor switch, and other switches such as a transistor, a GTO and an IGBT may be used.

[0019]

[Effect of device]

 As described above, according to the present invention, the primary winding of the main transformer is configured by star connection, and a plurality of windings having different winding ratios are provided in the electric path connecting each phase winding of the main transformer and the neutral point. A parallel transformer with a secondary winding, a series transformer whose primary winding is connected to the primary winding of the parallel transformer, and a plurality of secondary windings of the parallel transformer depending on the regulation voltage. Since a voltage regulator consisting of a semiconductor switch circuit that shorts and opens both ends is inserted, the following excellent effects can be obtained.

(1) Fast voltage adjustment is possible. (2) Since maintenance is switched without contact, maintenance and inspection is easy. (3) The number of tap stages can be increased depending on the combined voltage on the secondary side of the parallel transformer. (4) Since the voltage regulator is installed on the neutral point side, the insulation level can be lower than on the line side.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram showing details of an embodiment of the present invention.

FIG. 3 is a circuit diagram showing an example of a conventional load tap adjuster.

[Explanation of symbols]

11 _U ... primary winding 12 _U ... voltage regulator of the main transformer _{S 11 ~S 14, S 21 ~S} 24, S 31 ~S 34 ... thyristor switches T ₁ ... series transformer T ₂ ... parallel transformers

Claims (3)

[Scope of utility model registration request] 1. A primary winding of a main transformer is constituted by a star connection, and a plurality of secondary windings having different winding ratios are provided in an electric path connecting each phase winding of the main transformer and a neutral point. Having a parallel transformer, a series transformer having a primary winding connected to the primary winding of the parallel transformer, and short-circuiting both ends of a plurality of secondary windings of the parallel transformer according to a regulation voltage. A voltage regulator with a built-in transformer, wherein a voltage regulator composed of a semiconductor switch circuit to be opened is inserted. 2. The semiconductor switch circuit, wherein a plurality of semiconductor switches are bridge-connected to each other to form a plurality of bridge circuits, and the common connection points of adjacent semiconductor switches of the bridge circuits are opposed to each other. , Connecting a second common connection point to each of the secondary windings of the parallel transformer,
The built-in transformer according to claim 1, wherein the plurality of bridge circuits are connected in series via third and fourth common connection points of the common connection points that face each other. Voltage regulator. 3. The voltage regulator with a built-in transformer according to claim 2, wherein the semiconductor switch is formed by connecting thyristors in antiparallel.