KR102606905B1 - Transformer and high voltage switchgear - Google Patents

Abstract

The present invention relates to a power reception transformer and a high-voltage switchgear facility including the same, wherein the power reception transformer includes a plurality of instrument current transformers that output a modified current in which a large current is converted into a small current; a primary winding unit electrically connected to the plurality of instrument current transformers and including primary coils having a first connection; a secondary winding unit including a plurality of secondary coils having a second connection that is different from or the same as the first connection; and a first connection wire connecting the secondary coils of the secondary winding unit and a relay terminal connected to the KEPCO meter, wherein a transformed voltage obtained by converting a high voltage into a low voltage is induced in the secondary coils, and the high voltage and The large current is an extra high voltage supplied from KEPCO to the customer, and the low voltage and the small current are modified outputs and can be supplied to the KEPCO meter for measurement by the KEPCO meter.

Description

Transformer for power supply and high voltage switchgear equipment including the same {Transformer and high voltage switchgear}

The present invention relates to electrical equipment, and more specifically, to power receiving transformers and high-voltage switchgear equipment including the same.

High-voltage switchgear facilities may be installed to supply high-voltage electricity to consumers. In general, the high-voltage switchgear equipment includes an automatic fault section switch (Air Insulated Section Switch (AISS) or Auto Section Switch (ASS)), a metering out fit (MOF), a transformer (TR), and an electric power meter (e.g. , it can be composed of operator measurement devices such as peak demand meter (DM), reactive power meter (VAR), reactive power meter (VARH), and integrated power meter (WH). The AISS is a switch that classifies and separates fault sections, and can be used to prevent the spread of power outages by automatically separating faults to customers in order to improve supply reliability and prevent power outages at customers. The MOF transforms the high voltage (e.g., 3-phase 22.9kV AC or 3-phase 22.5kV AC, 60Hz) and large current received into the low voltage (e.g., 110V) and small current used in the KEPCO meter, and the low voltage and the small current is provided by the KEPCO meter. Meanwhile, the high voltage and the large current are converted into the low voltage and the small current by the MOF and can be provided to some of the transformers at the same time. The transformer can convert the high voltage into three-phase or single-phase 380V and 220V. The wiring method of the transformer can appropriately convert three-phase high voltage to 380V or 220V, including Δ-Δ, Δ-Y, Y-Y, Y-Δ, and single-phase-single-phase wiring, as needed. And the KEPCO meter is a device that measures the amount of power, and can calculate and display the amount of active power consumption and the amount of reactive power consumption by measuring voltage, current, and power factor. Specifically, the KEPCO meter can receive voltage and current transformed by the MOF (hereinafter referred to as transformed output) and calculate and display active and reactive power. The transformed output refers to the converted voltage and current output so that active and reactive power can be measured in the MOF.

However, the MOF is an independent device that is manufactured and installed at a separate cost and requires additional installation space at the location where the switchgear is installed, making it difficult to secure space for it when installed in the customer's facility, which is a problem that costs a lot of money. There is.

In addition, there are limitations in achieving compactness of the switchgear due to the need to maintain the volume and insulation distance of the MOF and the transformer (TR), and because the MOF and the transformer (TR) are manufactured separately, the number of parts required for manufacturing increases. This may increase the installation cost of the switchboard.

The technical problem to be solved by the present invention is to provide a power receiving transformer that minimizes the installation space of the high-voltage switchboard and improves installation costs by making the switchboard compact.

In addition, a high-voltage switchgear facility including the above-described power receiving transformer is provided.

According to one embodiment of the present invention, a plurality of instrument current transformers that output a modified current in which a large current is converted into a small current; a primary winding unit electrically connected to the plurality of instrument current transformers and including primary coils having a first connection; a secondary winding unit including a plurality of secondary coils having a second connection that is different from or the same as the first connection; and a first connection wire connecting the secondary coils of the secondary winding unit and a relay terminal connected to the KEPCO meter, wherein a transformed voltage obtained by converting a high voltage into a low voltage is induced in the secondary coils, and the high voltage and The large current is an extra high voltage supplied from KEPCO to the consumer, and the low voltage and the small current are transformed outputs. A power receiving transformer supplied to the KEPCO meter may be provided for measurement by the KEPCO meter.

According to one embodiment, when the first connection is a delta (Δ) connection and the second connection is a Y connection, the second terminal of the first coil on the primary side is electrically connected to the first terminal of the second coil on the primary side. , the second terminal of the second coil on the primary side is electrically connected to the first terminal of the third coil on the primary side, and the second terminal of the third coil on the primary side is electrically connected to the first terminal of the first coil on the primary side. The first terminal of the first coil on the secondary side is electrically connected to the first output terminal, the first terminal of the second coil on the secondary side is electrically connected to the second output terminal, and the first terminal of the third coil on the secondary side is electrically connected to the first output terminal. It is electrically connected to a third output terminal, and the second terminal of the first coil on the secondary side, the second terminal of the second coil on the secondary side, and the second terminal of the third coil on the secondary side are connected to a ground terminal, The first connection wire is a first wire connecting a first tab disposed on the first coil of the secondary side and the P1 terminal of the relay terminal, and a second tab disposed on the second coil of the secondary side. ) and a second wire connecting the P2 terminal of the relay terminal, a third wire connecting a third tab disposed on the third coil of the secondary side and the P3 terminal of the relay terminal, and a third wire connected to the ground terminal. It may include a fourth wire connecting the second terminal of the secondary first coil, the second terminal of the secondary second coil, the second terminal of the secondary third coil, and the P0 terminal of the relay terminal. . The first terminal of the first coil on the primary side is electrically connected to the first input terminal through a first instrument current transformer, and the first terminal of the second coil on the primary side is electrically connected to the second input terminal through a second instrument current transformer. It is electrically connected, and the first terminal of the third coil on the primary side may be electrically connected to the third input terminal through a third instrument current transformer. The line-to-line voltage or phase-to-phase voltage output from the first output terminal, the second output terminal, and the third output terminal may be higher than the low voltage.

According to one embodiment, when the first connection is a delta (Δ) connection and the second connection is a delta (Δ) connection, the second terminal of the first coil on the primary side is connected to the first terminal of the second coil on the primary side. electrically connected, the second terminal of the second coil on the primary side is electrically connected to the first terminal of the third coil on the primary side, and the second terminal of the third coil on the primary side is the first terminal of the first coil on the primary side. is electrically connected to, the second terminal of the first coil on the secondary side is electrically connected to the first terminal of the second coil on the secondary side, and the second terminal of the second coil on the secondary side is electrically connected to the first terminal of the third coil on the secondary side. electrically connected, the second terminal of the secondary third coil is electrically connected to the first terminal of the primary first coil, and the first terminal of the secondary first coil is electrically connected to the first output terminal, The first terminal of the second coil on the secondary side is electrically connected to the second output terminal, the first terminal of the third coil on the secondary side is electrically connected to the third output terminal, and the first terminal of the fourth coil on the secondary side is electrically connected to the third output terminal. It is electrically connected to the P1 terminal of the relay terminal, the first terminal of the fifth coil on the secondary side is electrically connected to the P2 terminal of the relay terminal, and the first terminal of the sixth coil on the secondary side is electrically connected to the P3 terminal of the relay terminal. connected, the second terminal of the fourth coil on the secondary side, the second terminal of the fifth coil on the secondary side, and the second terminal of the sixth coil on the secondary side are connected to a neutral point, and the first connection wire is connected to the secondary side. 4th coil. It may include a Y connection of the fifth coil and the sixth coil. The first terminal of the first coil on the primary side is electrically connected to the first input terminal through a first instrument current transformer, and the first terminal of the second coil on the primary side is electrically connected to the second input terminal through a second instrument current transformer. It is electrically connected, and the first terminal of the third coil on the primary side may be electrically connected to the third input terminal through a third instrument current transformer. The line-to-line voltage or phase-to-phase voltage output from the first output terminal, the second output terminal, and the third output terminal may be higher than the low voltage.

According to one embodiment, when the first connection is a Y connection and the second connection is a Y connection, the first terminal of the first coil on the primary side is electrically connected to the first input terminal, and the first terminal of the second coil on the primary side is electrically connected to the first input terminal. 1 terminal is electrically connected to the second input terminal, the first terminal of the third coil on the primary side is electrically connected to the third input terminal, the second terminal of the first coil on the primary side, the second terminal of the second coil on the primary side 2 terminal and the second terminal of the third coil on the primary side are connected to the first neutral point, the first terminal of the first coil on the secondary side is electrically connected to the first output terminal, and the first terminal of the second coil on the secondary side is electrically connected to the first neutral point. It is electrically connected to a second output terminal, and the first terminal of the secondary third coil is electrically connected to the third output terminal, the second terminal of the secondary first coil, the second terminal of the secondary second coil, And the second terminal of the third coil on the secondary side is connected to a second neutral point, and the first connection wire connects a first tab disposed on the first coil on the secondary side and the P1 terminal of the relay terminal. A first wire connecting a second tab disposed on the second coil of the secondary side and the P2 terminal of the relay terminal, a third tab disposed on the third coil of the secondary side ) and a third wire connecting the P3 terminal of the relay terminal and a fourth wire connecting the second neutral point and the P0 terminal of the relay terminal. The first terminal of the first coil on the primary side is electrically connected to the first input terminal through a first instrument current transformer, and the first terminal of the second coil on the primary side is electrically connected to the second input terminal through a second instrument current transformer. It is electrically connected, and the first terminal of the third coil on the primary side may be electrically connected to the third input terminal through a third instrument current transformer. The line-to-line voltage or phase-to-phase voltage output from the first output terminal, the second output terminal, and the third output terminal may be higher than the low voltage.

In one embodiment, it may include a second connection wire that supplies the degeneration current of the plurality of instrument current transformers to the relay terminal. The second connection wire is a fifth wire connecting the first output terminal of the first instrument current transformer and the 1S terminal of the relay terminal, and a fifth wire connecting the first output terminal of the second instrument current transformer and the 2S terminal of the relay terminal. 6th wiring, 7th wiring connecting the 1st output terminal of the 3rd instrument current transformer and the 3S terminal of the relay terminal, and 7th wiring connecting the 2nd output terminal of the 1st instrument current transformer and the 1L terminal of the relay terminal. 8 wiring, a 9th wiring connecting the 2nd output terminal of the second instrument current transformer and the 2L terminal of the relay terminal, and a 9th wiring connecting the 2nd output terminal of the third instrument current transformer and the 3L terminal of the relay terminal. May contain 10 wires.

In one embodiment, the KEPCO meter may include a peak demand meter (DM), a reactive power meter (VAR), a reactive power meter (VARH), a total power meter (WH), or a combination thereof.

According to another embodiment of the present invention, a high-voltage switchgear facility including the above-described power receiving transformer can be provided.

According to one embodiment of the present invention, instead of a separate MOF device in the high-voltage switchgear, the first connection wire connecting the secondary coils of the transformer and the relay terminal connected to the KEPCO meter so that the secondary coil of the transformer has the function of an instrument transformer. By including, it is possible to provide a power receiving transformer that minimizes the installation space of the high-voltage switchgear and improves the parts and installation costs by making the switchboard compact.

In addition, since the transformer and MOF can be accommodated in one enclosure, compaction of the high-voltage switchgear can be realized, making it possible to easily install the high-voltage switchgear even in narrow places such as the city center.

Additionally, according to another embodiment of the present invention, a high-voltage switchgear facility having the above-described advantages can be provided.

1A and 1B are circuit wiring diagrams of a power receiving transformer according to the first embodiment of the present invention.
FIG. 1C is a diagram showing one of three transformers constituting the power receiving transformer of FIGS. 1A and 1B.
Figures 2a and 2b are circuit wiring diagrams of a power receiving transformer according to a second embodiment of the present invention.
FIG. 2C is a diagram showing one of three transformers constituting the power receiving transformer of FIGS. 2A and 2B.
3A to 3C are circuit wiring diagrams of a power receiving transformer according to a third embodiment of the present invention.
FIG. 3D is a diagram showing one of three transformers constituting the power receiving transformer of FIGS. 3A to 3C.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art, and the following examples may be modified into various other forms, and the scope of the present invention is as follows. It is not limited to examples. Rather, these embodiments are provided to make the disclosure more faithful and complete, and to fully convey the spirit of the invention to those skilled in the art.

In the drawings, like symbols refer to like elements. Additionally, as used herein, the term “and/or” includes any one and all combinations of one or more of the corresponding listed items.

The terms used herein are used to describe examples and are not intended to limit the scope of the invention. In addition, even if described in the specification as a singular number, plural forms may be included unless the context clearly indicates singularity. Additionally, as used herein, the terms "comprise" and/or "comprising" specify the presence of stated features, numbers, steps, operations, members, elements and/or groups thereof. It does not exclude the presence or addition of other shapes, numbers, movements, members, elements and/or groups.

Additionally, for those skilled in the art, a structure or shape disposed “adjacent” to another shape may have a portion that overlaps or is disposed beneath the adjacent shape.

As used herein, “below,” “above,” “upper,” “lower,” “horizontal,” or “vertical.” Relative terms such as may be used to describe the relationship that one component, layer or region has with another component, layer or region, as shown in the drawings. It should be understood that these terms encompass not only the directions indicated in the drawings, but also other directions of the device.

Hereinafter, embodiments of the invention will be described with reference to cross-sectional views schematically showing ideal embodiments (and intermediate structures) of the invention. In these drawings, for example, the size and shape of members may be exaggerated for convenience and clarity of explanation, and in actual implementation, variations in the depicted shapes may be expected. Accordingly, embodiments of the present invention should not be construed as limited to the specific shape of the area shown herein. Additionally, reference signs for members in the drawings refer to the same members throughout the drawings.

The present invention includes a plurality of instrument current transformers that output a current converted from a large current to a small current (hereinafter referred to as deformed current), and primary coils that are electrically connected to the plurality of instrument current transformers and have a first connection. It includes a primary side winding section, a secondary side winding section including secondary side coils having a second connection that is different from or the same as the first connection, and a first connection line connecting between the secondary side coils and the terminal of the electricity meter. In the secondary coils, a transformed voltage obtained by converting the high voltage to a low voltage is induced. The high voltage and the large current are extra high voltages supplied from KEPCO to customers, and the low voltage and the small current are the transformed output, which is the maximum demand power, It can be supplied to the KEPCO meter to measure reactive power and the amount of reactive power.

FIGS. 1A and 1B are circuit wiring diagrams of the power receiving transformer according to the first embodiment of the present invention, and FIG. 1C is a diagram showing one of three transformers constituting the power receiving transformer of FIGS. 1A and 1B. The three transformers may be comprised of three single-phase transformers or one three-phase transformer. Preferably, in FIGS. 1A and 1B, the three transformers may be one three-phase transformer.

Referring to FIGS. 1A and 1B, the power receiving transformer 100 includes an input terminal (IT), an output terminal (OT), three primary coils (C11, C12, C13), and three secondary coils (C21, C22, C23). ) and instrument current transformers (CT1, CT2, CT3: current transformers) that are respectively combined with the three primary coils (C11, C12, C13). The input terminal (IT) has three input terminals (L1, L2, L3), and the output terminal (OT) may include four output terminals (LV1, LV2, LV3, E). The three input terminals (L1, L2, L3) are terminals that receive three-phase power from KEPCO, and each has a phase, b phase, and c phase (or R-S-T phase or u-v-w). The three output terminals (LV1, LV2, and LV3) are output terminals corresponding to the input terminals (L1, L2, and L3), respectively, and the output terminal (E) may be a ground terminal (or neutral point).

In one embodiment, the three primary coils (C11, C12, C13) have a delta (Δ) connection (WC1) and the three secondary coils (C21, C22, C23) have a Y connection (WC2). Specifically, for the delta (Δ) connection (WC1) of the three primary coils (C11, C12, C13), one end (P1) of the primary coil (C11) is connected to the input terminal through the instrument current transformer (CT1). It is connected to (L1), and the other end (P2) of the primary side coil (C11) and one end (P3) of the primary side coil (C12) may be connected through the lead wire (CC1). In addition, one end (P3) of the primary coil (C12) is connected to the input terminal (L2) through the instrument current transformer (CT2), and the other end (P4) of the primary coil (C12) and the primary coil (C13) ) can be connected to one end (P5) through a lead wire (CC2). In addition, one end (P5) of the primary coil (C13) is connected to the input terminal (L3) through the instrument current transformer (CT3), and the other end (P6) of the primary coil (C13) and the primary coil (C11) are connected to the input terminal (L3). ) may be connected through a lead wire (CC3). That is, the three primary coils (C11, C12, and C13) have a delta (Δ) connection (WC1) through the three lead wires (CC1, CC2, and CC3).

In one embodiment, for the Y connection (WC2) of the three secondary coils (C21, C22, C23), one end (S1) of the secondary coil (C21) is connected to the output terminal (LV1), and the secondary coil (C21, C22, C23) is connected to the output terminal (LV1). The other end (S2) of the coil (C21) is connected to the ground terminal (E), one end (S3) of the secondary coil (C22) is connected to the output terminal (LV2), and the other end of the secondary coil (C22) is connected to the output terminal (LV2). The end (S4) is connected to the ground terminal (E), one end (S5) of the secondary coil (C23) is connected to the output terminal (LV3), and the other end (S6) of the secondary coil (C23) is grounded. It can be connected to terminal (E). That is, the other ends (S2, S4, S6) of the secondary coils (C21, C22, C23) are connected through the neutral point (or ground terminal (E)) to have a Y connection (WC2).

In addition, the three secondary coils (C21, C22, C23) each include a tap (T1, T2, T3), and the instrument transformer uses the tap (T1) and the ground terminal (E). (PT1) can be configured, and the instrument transformer (PT2) can be configured using the tap (T2) and the ground terminal (E), and the instrument transformer (PT2) can be configured using the tap (T3) and the ground terminal (E). You can configure an instrument transformer (PT3) using . In addition, each tap (T1, T2, T3) is connected to the P1, P2, and P3 terminals of the relay terminal (DM-TB), and the other end (S2, S4, S6) can be connected to the P0 terminal of the relay terminal (DM-TB). The P0 terminal of the relay terminal (DM-TB) can be connected to the ground terminal (E) or the neutral point of the Y connection (WC2).

In addition, the output terminals (LV1, LV2, LV3, E) of the power receiving transformer 100 may be connected to a zero-phase current transformer (ZCT) (not shown) that detects the zero-phase current of the earth leakage alarm, and the power receiving transformer 100 and a zero phase current transformer (ZCT) (not shown) can be accommodated in one enclosure.

Referring to FIG. 1C, when a primary voltage (high voltage) of approximately 22.9 kV is supplied to the primary coils (C11, C12, and C13) through the input terminals (L1, L2, and L3), the primary coils (C11, C12) , C13)'s primary voltage of 22.9kV is determined by the secondary line-to-line voltage of 380V and 220V by the number of turns of the primary coils (C11, C12, C13) and the secondary coils (C21, C22, C23). Phase voltage can be induced in the secondary coils (C21, C22, C23). In addition, in the present invention, the instrument transformer (PT1, PT2, PT3) implemented through the taps (T1, T2, T3) of the secondary coils (C21, C22, C23) transforms the primary voltage (high voltage) of 22.9 kV into a low voltage. It can be converted to (e.g. about 110V) and output.

In one embodiment, the power receiving transformer 100 is for the purpose of measuring KEPCO meters (e.g., maximum demand meter (DM), reactive watt hour meter (VAR), reactive watt hour meter (VARH), integrated watt hour meter (WH), etc.), and has an input terminal. The high voltage and large current supplied from KEPCO through (L1, L2, L3) can be converted into low voltage (about 110V) and low current (about 5A) (hereinafter referred to as transformed output) and provided to the KEPCO meter. The DM is an instrument that measures peak power among the power used by the load and transmits it to KEPCO, the WH is an instrument that integrates the power for a month and measures the total amount of power used in a month, and the VAR is a device that measures reactive power. VARH is an instrument that measures and meters reactive power.

For measurement of the KEPCO meter, the power receiving transformer 100 may be coupled to a relay terminal (DM-TB) connected to the KEPCO meter. The relay terminal (DM-TB) is disposed between the KEPCO meter and the power receiving transformer 100, and can electrically connect the power receiving transformer 100 and the KEPCO meter. The relay terminal (DM-TB) has 10 terminals including 1S, P1, 2S, P2, 3S, P3, P0, 1L, 2L, and 3L, and the 1S, 2S, 3S, 1L, 2L, and 3L terminals are connected to the instrument. This terminal is connected to the current transformer (CT), and terminals P3, P2, P1, and P0 are terminals connected to the instrument transformer (PT). Specifically, the output terminal of the instrument current transformer (CT1) is connected to the 1S and 1L terminals of the relay terminal (DM-TB), and the output terminal of the instrument current transformer (CT2) is connected to the 2S and 2L terminals of the relay terminal (DM-TB). connected, and the output terminal of the instrument current transformer (CT3) can be connected to the 3S and 3L terminals of the relay terminal (DM-TB). On the other hand, the output terminal of the instrument transformer (PT1) is connected to the P1 and P0 terminals of the relay terminal (DM-TB), and the output terminal of the instrument transformer (PT2) is connected to the P2 and P0 terminals of the relay terminal (DM-TB). The output terminal of the instrument transformer (PT3) can be connected to the P3 and P0 terminals of the relay terminal (DM-TB). Here, the tabs (T1, T2, T3) of the secondary coils (C21, C22, C23) constituting the instrument transformer (PT1, PT2, PT3) and P3, P2, P1, P0 of the relay terminal (DM-TB) The wiring between the terminals is called the first connection wiring (WL1), and the wiring between the output terminal of the instrument current transformer (CT1, CT2, CT3) and the 1S, 2S, 3S, 1L, 2L, and 3L terminals of the relay terminal (DM-TB) The wiring is referred to as the second connection wiring (WL2).

FIGS. 2A and 2B are circuit wiring diagrams of a power receiving transformer according to a second embodiment of the present invention, and FIG. 2C is a diagram showing one of three transformers constituting the power receiving transformer of FIGS. 2A and 2B. The three transformers may be comprised of three single-phase transformers or one three-phase transformer. Preferably, in FIGS. 2A and 2B, the three transformers may be one three-phase transformer.

2A and 2B, the power receiving transformer 200 includes an input terminal (IT), an output terminal (OT), three primary coils (C11, C12, C13), and six secondary coils (C21, C22, C23). , C31, C32, C33) and three primary coils (C11, C12, C13) and instrument current transformers (CT1, CT2, CT3), respectively. The input terminal (IT) has three input terminals (L1, L2, L3), and the output terminal (OT) may include four output terminals (LV1, LV2, LV3, E). The three input terminals (L1, L2, L3) are terminals that receive three-phase power from KEPCO, and each has a phase, b phase, and c phase (or R-S-T phase or u-v-w). The four output terminals (LV1, LV2, and LV3) are output terminals corresponding to the input terminals (L1, L2, and L3), respectively, and the output terminal (E) may be a terminal connected to the neutral point or ground.

In one embodiment, the three primary coils (C11, C12, C13) have a first delta (Δ) connection (WC1) and the three secondary coils (C21, C22, C23) have a second delta (Δ) connection. It has a connection (WC2), and the three secondary coils (C31, C32, C33) have a Y connection (WC3). As shown in Figure 2c, the secondary coil (C21) and coil (C31) are arranged in series to form a secondary coil corresponding to the primary coil (C11), and the secondary coil (C22) and coil (C32) are arranged in series. A secondary coil corresponding to the primary coil C12 may be formed, and the secondary coil C23 and the coil C33 may be arranged in series to form a secondary coil corresponding to the primary coil C13. That is, it has a structure in which two secondary coils are arranged corresponding to one primary coil.

Specifically, for the first delta (Δ) connection (WC1) of the three primary coils (C11, C12, C13), one end (P1) of the primary coil (C11) is connected through the instrument current transformer (CT1). It is connected to the input terminal (L1), and the other end (P2) of the primary coil (C11) and one end (P3) of the primary coil (C12) may be connected through the lead wire (CC1). In addition, one end (P3) of the primary coil (C12) is connected to the input terminal (L2) through the instrument current transformer (CT2), and the other end (P4) of the primary coil (C12) and the primary coil (C13) ) can be connected to one end (P5) through a lead wire (CC2). In addition, one end (P5) of the primary coil (C13) is connected to the input terminal (L3) through the instrument current transformer (CT3), and the other end (P6) of the primary coil (C13) and the primary coil (C11) are connected to the input terminal (L3). ) may be connected through a lead wire (CC3). That is, the three primary coils (C11, C12, C13) have a first delta (Δ) connection (WC1) through three lead wires (CC1, CC2, CC3).

Similarly, for the second delta (Δ) (WC2) of the three secondary coils (C21, C22, C23), one end (S1) of the secondary coil (C21) is connected to the output terminal (LV1), and 2 The other end S2 of the primary coil C21 and one end S5 of the secondary coil C22 may be connected through a first lead wire. In addition, one end (S5) of the secondary coil (C22) is connected to the output terminal (LV2), and the other end (S6) of the secondary coil (C22) and one end (S9) of the secondary coil (C23) are connected to the output terminal (LV2). It can be connected through a second lead wire. In addition, one end (S9) of the secondary coil (C23) is connected to the output terminal (LV3), and the other end (S10) of the secondary coil (C23) and one end (S1) of the secondary coil (C21) are connected to the output terminal (LV3). It can be connected through a third lead wire. That is, the three secondary coils (C21, C22, C23) have a second delta (Δ) (WC2) through the three lead wires.

For the Y connection (WC3) of the three secondary coils (C31, C32, C33), one end (S3) of the secondary coil (C31) is connected to the terminal (P1) of the relay terminal (DM-TB), The other end (S4) of the secondary coil (C31) is connected to the terminal (P0) of the relay terminal (DM-TB), and one end (S7) of the secondary coil (C32) is connected to the relay terminal (DM-TB). It is connected to the terminal (P2), the other end (S8) of the secondary coil (C32) is connected to the terminal (P0) of the relay terminal (DM-TB), and one end (S11) of the secondary coil (C33) is connected to the It is connected to the terminal (P3) of the relay terminal (DM-TB), and the other end (S12) of the secondary coil (C33) may be connected to the terminal (P0) of the relay terminal (DM-TB). The other ends (S4, S8, and S12) of the secondary coils (C31, C32, and C33) have a Y connection (WC3) by being tied through a neutral point. In the present invention, the three secondary coils (C31, C32, C33) can function as an instrument transformer (PT1), an instrument transformer (PT2), and an instrument transformer (PT3), respectively.

In addition, the output terminals (LV1, LV2, and LV3) of the power receiving transformer 200 can be connected to a zero-phase current transformer (ZCT) (not shown) that detects the zero-phase current of the earth leakage alarm, and the power receiving transformer 200 and the zero-phase current transformer (ZCT) (not shown) can be connected to A current transformer (ZCT) (not shown) may be housed in one enclosure.

Referring to FIG. 2C, when a primary voltage (high voltage) of approximately 22.9 kV is supplied to the primary coils (C11, C12, and C13) through the input terminals (L1, L2, and L3), the primary coils (C11, C12) , C13)'s primary voltage of 22.9kV is determined by the secondary line-to-line voltage of 380V and 220V by the number of turns of the primary coils (C11, C12, C13) and the secondary coils (C21, C22, C23). Phase voltage can be induced in the secondary coils (C21, C22, C23), the number of turns of the primary coils (C11, C12, C13) and the secondary coil (PT1, PT2, PT3) that functions as an instrument transformer (PT1, PT2, PT3). Depending on the number of turns (C31, C32, C33), the primary voltage (high voltage) of 22.9 kV can be converted to a low voltage (e.g. about 110 V) and output.

In one embodiment, the power receiving transformer 200 is for the purpose of measuring KEPCO meters (e.g., maximum demand meter (DM), reactive watt hour meter (VAR), reactive watt hour meter (VARH), integrated watt hour meter (WH), etc.), and has an input terminal. The high voltage and large current supplied from KEPCO through (L1, L2, L3) can be converted into low voltage (about 110V) and low current (about 5A) (hereinafter referred to as transformed output) and provided to the KEPCO meter. For measurement of the KEPCO meter, the power receiving transformer 100 may be coupled to a relay terminal (DM-TB) connected to the KEPCO meter. The relay terminal (DM-TB) is disposed on the KEPCO meter or the power receiving transformer 100 and can electrically connect the power receiving transformer 100 and the KEPCO meter. Specifically, the output terminal of the instrument current transformer (CT1) is connected to the 1S and 1L terminals of the relay terminal (DM-TB), and the output terminal of the instrument current transformer (CT2) is connected to the 2S and 2L terminals of the relay terminal (DM-TB). connected, and the output terminal of the instrument current transformer (CT3) can be connected to the 3S and 3L terminals of the relay terminal (DM-TB). On the other hand, the S3 terminal of the secondary coil (C31), which functions as an instrument transformer (PT1), is connected to the P1 terminal of the relay terminal (DM-TB), and the S4 terminal of the secondary coil (C31) is connected to the relay terminal (DM-TB). TB) can be connected to the P0 terminal. The S7 terminal of the secondary coil (C32), which functions as an instrument transformer (PT2), is connected to the P2 terminal of the relay terminal (DM-TB), and the S8 terminal of the secondary coil (C32) is connected to the relay terminal (DM-TB). It can be connected to the P0 terminal of Lastly, the S11 terminal of the secondary coil (C33), which functions as an instrument transformer (PT3), is connected to the P3 terminal of the relay terminal (DM-TB), and the S12 terminal of the secondary coil (C32) is connected to the relay terminal (DM-TB). TB) can be connected to the P0 terminal. Here, the wiring between the secondary coils (C31, C32, C33) constituting the instrument transformer (PT1, PT2, PT3) and the P3, P2, P1, and P0 terminals of the relay terminal (DM-TB) is called the first connection wiring. It is called (WL1), and the wiring between the output terminal of the instrument current transformer (CT1, CT2, CT3) and the 1S, 2S, 3S, 1L, 2L, 3L terminal of the relay terminal (DM-TB) is the second connection wiring (WL2). It is called.

FIGS. 3A to 3C are circuit wiring diagrams of the power receiving transformer 300 according to the third embodiment of the present invention, and FIG. 3D is a diagram showing one of the three transformers constituting the power receiving transformer of FIGS. 3A to 3C. . The three transformers may be comprised of three single-phase transformers or one three-phase transformer. Figure 3a shows a case implemented with three single-phase transformers, and Figure 3b shows a case implemented with one three-phase transformer.

Referring to FIGS. 3A and 3C, the power receiving transformer 300 includes an input terminal (IT), an output terminal (OT), three primary coils (C11, C12, C13), and three secondary coils (C21, C22, C23). ) and three primary coils (C11, C12, C13) and instrument current transformers (CT1, CT2, CT3), respectively. The input terminal (IT) has four input terminals (L1, L2, L3, N), and the output terminal (OT) may include four output terminals (LV1, LV2, LV3, E). The four input terminals (L1, L2, L3) are terminals that receive three-phase power from KEPCO, and each has a phase, b phase, and c phase (or R-S-T phase or u-v-w). The input terminal (N) may be a ground terminal or a neutral point. The three output terminals (LV1, LV2, and LV3) are output terminals corresponding to the input terminals (L1, L2, and L3), respectively, and the output terminal (E) may be a ground terminal or a neutral point.

In one embodiment, the three primary coils (C11, C12, C13) have a first Y connection (WC1) and the three secondary coils (C21, C22, C23) have a second Y connection (WC4). . Specifically, for the first Y connection (WC1) of the three primary coils (C11, C12, C13), one end (P1) of the primary coil (C11) is connected to the input terminal (L1), and the primary coil (C11) is connected to the input terminal (L1). The other end (P2) of the coil (C11) is connected to the neutral point (N), one end (P3) of the primary coil (C12) is connected to the input terminal (L2), and the other end of the primary coil (C12) is connected to the input terminal (L2). (P4) is connected to the neutral point (N), one end (P5) of the primary coil (C13) is connected to the input terminal (L3), and the other end (P6) of the primary coil (C13) is connected to the neutral point (N). ) can be connected to. The other ends (P2, P4, P6) of the primary coils (C11, C12, C13) are connected through the neutral point (N) and have a first Y connection (WC1). The neutral point (N) may be connected to the ground terminal.

In one embodiment, for the second Y connection (WC4) of the three secondary coils (C21, C22, C23), one end (S1) of the secondary coil (C21) is connected to the output terminal (LV1), The other end (S2) of the secondary coil (C21) is connected to the ground terminal (E), one end (S3) of the secondary coil (C22) is connected to the output terminal (LV2), and the secondary coil (C22) The other end (S4) is connected to the ground terminal (E), one end (S5) of the secondary coil (C23) is connected to the output terminal (LV3), and the other end (S6) of the secondary coil (C23) is connected to the output terminal (LV3). Can be connected to the ground terminal (E). The other ends (S2, S4, S6) of the secondary coils (C21, C22, C23) are connected through the ground terminal (E) to have a second Y connection (WC4). The ground terminal (E) may be connected to the neutral point of the second Y connection (WC4).

The three secondary coils (C21, C22, C23) each have a tap (T1, T2, T3), and the instrument transformer (PT1) uses the tap (T1) and the ground terminal (E). ) can be configured, and the instrument transformer (PT2) can be configured using the tap (T2) and the ground terminal (E), and the instrument transformer (PT2) can be configured using the tap (T3) and the ground terminal (E). Thus, an instrument transformer (PT3) can be configured. In addition, each tap (T1, T2, T3) is connected to the P1, P2, and P3 terminals of the relay terminal (DM-TB), and the other end (S2, S4, S6) can be connected to the P0 terminal of the relay terminal (DM-TB). The P0 terminal of the relay terminal (DM-TB) may be connected to the ground terminal (E2).

In addition, the output terminals (LV1, LV2, LV3, E) of the power receiving transformer 300 can be connected to a zero-phase current transformer (ZCT) (not shown) that detects the zero-phase current of the earth leakage alarm, and the power receiving transformer 300 and a zero phase current transformer (ZCT) (not shown) can be accommodated in one enclosure.

Referring to FIG. 3d, when a primary voltage (high voltage) of approximately 22.9 kV is supplied to the primary coils (C11, C12, and C13) through the input terminals (L1, L2, and L3), the primary coils (C11, C12) , C13)'s primary voltage of 22.9kV is determined by the secondary line-to-line voltage of 380V and 220V by the number of turns of the primary coils (C11, C12, C13) and the secondary coils (C21, C22, C23). Phase voltage can be induced in the secondary coils (C21, C22, C23). In addition, in the present invention, the instrument transformer (PT1, PT2, PT3) implemented through the taps (T1, T2, T3) of the secondary coils (C21, C22, C23) transforms the primary voltage (high voltage) of 22.9 kV into a low voltage. It can be converted to (e.g. about 110V) and output.

In one embodiment, the power receiving transformer 300 is for the purpose of measuring KEPCO meters (e.g., maximum demand meter (DM), reactive watt hour meter (VAR), reactive watt hour meter (VARH), integrated watt hour meter (WH), etc.), and has an input terminal. The high voltage and large current supplied from KEPCO through (L1, L2, L3) can be converted into low voltage (about 110V) and low current (about 5A) (hereinafter referred to as transformed output) and provided to the KEPCO meter. For measurement of the KEPCO meter, the power receiving transformer 100 may be coupled to a relay terminal (DM-TB) connected to the KEPCO meter. The relay terminal (DM-TB) is disposed on the KEPCO meter or the power receiving transformer 100 and can electrically connect the power receiving transformer 100 and the KEPCO meter. The output terminal of the instrument current transformer (CT1) is connected to the 1S and 1L terminals of the relay terminal (DM-TB), and the output terminal of the instrument current transformer (CT2) is connected to the 2S and 2L terminals of the relay terminal (DM-TB). The output terminal of the instrument current transformer (CT3) can be connected to the 3S and 3L terminals of the relay terminal (DM-TB). On the other hand, the output terminal of the instrument transformer (PT1) is connected to the P1 and P0 terminals of the relay terminal (DM-TB), and the output terminal of the instrument transformer (PT2) is connected to the P2 and P0 terminals of the relay terminal (DM-TB). The output terminal of the instrument transformer (PT3) can be connected to the P3 and P0 terminals of the relay terminal (DM-TB). Here, the tabs (T1, T2, T3) of the secondary coils (C21, C22, C23) constituting the instrument transformer (PT1, PT2, PT3) and P3, P2, P1, P0 of the relay terminal (DM-TB) The wiring between the terminals is called the first connection wiring (WL1), and the wiring between the output terminal of the instrument current transformer (CT1, CT2, CT3) and the 1S, 2S, 3S, 1L, 2L, and 3L terminals of the relay terminal (DM-TB) The wiring is referred to as the second connection wiring (WL2).

Conventionally, a metering out fit (MOF) is installed in front of the power receiving transformer 100 for the purpose of measuring KEPCO meters (e.g. DM, VAR, VARH, WH, etc.). The MOF consists of a set of CT (current transformer) and PT (potential transformer) and is placed in a steel box (or enclosure) to transform high voltage and large current into low voltage and small current and supply them to the KEPCO meter. However, the conventional MOF is manufactured and installed as an independent device at a separate cost and requires additional installation space at the location where the switchgear is installed, making it difficult to secure space for it when installed in a customer's facility and high cost.

On the other hand, in the present invention, instead of a separate panel-type MOF device, an instrument current transformer (CT1, CT2, CT3) is accommodated inside the power receiving transformer 100, and the three secondary coils (C21, C22, C23) are installed. By configuring instrument transformers (PT1, PT2, PT3) using taps (T1, T2, T3), the installation space of the switchgear can be reduced because there is no need to use MOF devices manufactured at separate costs. Costs can be reduced. Additionally, since there is no need to install MOF devices, the construction period can be shortened.

Additionally, the overcurrent strength of a conventional instrument transformer can be determined by considering the current ratio of the instrument transformer. If the current ratio of the instrument transformer for a 22.9kV customer is in the range of 5/5 to 15/5, the overcurrent intensity is determined to be 150 times, and if the current ratio is in the range of 20/5 to 50/5, the overcurrent intensity is determined to be 75 times. This means that there is no thermal or mechanical problem even if the primary current flows as much as a multiple of the overcurrent intensity corresponding to the corresponding current ratio range. That is, conventionally, even if up to 2.25KA (=150*15) overcurrent flows in the current ratio range of 5/5 to 15/5, or up to 3.75KA (=75*50) overcurrent in the current ratio range of 20/5 to 50/5, The MOF is designed so that there are no thermal or mechanical problems even if there is a flow.

However, in the present invention, the instrument transformer is implemented using the secondary coil of the transformer instead of using a separate instrument transformer (PT), so that the transformer has a relatively larger thickness and greater strength than the coil used in the MOF. By using a coil, larger overcurrents (e.g., approximately 12.5KA) can be tolerated than before.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible without departing from the technical spirit of the present invention. It will be clear to those who have knowledge.

100, 200, 300: Transformer for power supply
IT: Input stage
OT: Output stage
L1, L2, L3: Input terminal
LV1, LV2, LV3: Output terminals
N: neutral point
E: Ground terminal
P1-P6: Terminals of primary coil
S1-S12: Terminals of secondary coil
CC1, CC2, CC3: Lead wire
DM-TB: relay terminal
CT1, CT2, CT3: Instrument current transformer
PT1, PT2, PT3: Instrument transformer
WC1, WC2, WC3, WC4: Delta or Y connection

Claims (14)

A plurality of instrument current transformers that output transformed current;
a primary winding unit electrically connected to the plurality of instrument current transformers and including primary coils having a first connection;
a secondary winding unit including a plurality of secondary coils having a second connection that is different from or the same as the first connection; and
It includes a first connection wire connecting the secondary coils of the secondary winding unit and the relay terminal of the KEPCO meter,
A transformation voltage is induced in the secondary coils,
The transformation current and the transformation voltage are supplied to the KEPCO meter for measurement by the KEPCO meter. According to claim 1,
If the first connection is a delta (Δ) connection and the second connection is a Y connection,
The second terminal of the first coil on the primary side is electrically connected to the first terminal of the second coil on the primary side, and the second terminal of the second coil on the primary side is electrically connected to the first terminal of the third coil on the primary side, The second terminal of the third coil on the primary side is electrically connected to the first terminal of the first coil on the primary side,
The first terminal of the first coil on the secondary side is electrically connected to the first output terminal, the first terminal of the second coil on the secondary side is electrically connected to the second output terminal, and the first terminal of the third coil on the secondary side is electrically connected to the third output terminal. It is electrically connected to an output terminal, and the second terminal of the first coil on the secondary side, the second terminal of the second coil on the secondary side, and the second terminal of the third coil on the secondary side are connected to a neutral point,
The first connection wire is a first wire connecting a first tab disposed on the first coil of the secondary side and the P1 terminal of the relay terminal, and a second tab disposed on the second coil of the secondary side ( a second wire connecting a tap) and the P2 terminal of the relay terminal, a third wire connecting a third tap disposed on the third coil of the secondary side and the P3 terminal of the relay terminal, and a third wire connected to the neutral point. For power reception, including a fourth wire connecting the second terminal of the secondary first coil, the second terminal of the secondary second coil, the second terminal of the secondary third coil, and the P0 terminal of the relay terminal. Transformers. According to claim 2,
The first terminal of the first coil on the primary side is electrically connected to the first input terminal through a first instrument current transformer,
The first terminal of the second coil on the primary side is electrically connected to the second input terminal through a second instrument current transformer,
A power receiving transformer wherein the first terminal of the third coil on the primary side is electrically connected to the third input terminal through a third instrument current transformer. According to claim 2,
A power receiving transformer wherein the line-to-line voltage or phase-to-phase voltage output from the first output terminal, the second output terminal, and the third output terminal is higher than the transformation voltage. According to claim 1,
If the first connection is a delta (Δ) connection and the second connection is a delta (Δ) connection,
The second terminal of the first coil on the primary side is electrically connected to the first terminal of the second coil on the primary side, and the second terminal of the second coil on the primary side is electrically connected to the first terminal of the third coil on the primary side, The second terminal of the third coil on the primary side is electrically connected to the first terminal of the first coil on the primary side,
The second terminal of the first coil on the secondary side is electrically connected to the first terminal of the second coil on the secondary side, and the second terminal of the second coil on the secondary side is electrically connected to the first terminal of the third coil on the secondary side, The second terminal of the third coil on the secondary side is electrically connected to the first terminal of the first coil on the primary side, the first terminal of the first coil on the secondary side is electrically connected to the first output terminal, and the second terminal on the secondary side The first terminal of the coil is electrically connected to the second output terminal, and the first terminal of the third coil on the secondary side is electrically connected to the third output terminal,
The first terminal of the fourth coil on the secondary side is electrically connected to the P1 terminal of the relay terminal, the first terminal of the fifth coil on the secondary side is electrically connected to the P2 terminal of the relay terminal, and the first terminal of the sixth coil on the secondary side is electrically connected to the P2 terminal of the relay terminal. The terminal is electrically connected to the P3 terminal of the relay terminal, and the second terminal of the fourth coil on the secondary side, the second terminal of the fifth coil on the secondary side, and the second terminal of the sixth coil on the secondary side are connected to the neutral point. ,
The first connection wire is the fourth coil on the secondary side. A power receiving transformer including Y connections of the fifth and sixth coils. According to claim 5,
The first terminal of the first coil on the primary side is electrically connected to the first input terminal through a first instrument current transformer,
The first terminal of the second coil on the primary side is electrically connected to the second input terminal through a second instrument current transformer,
A power receiving transformer wherein the first terminal of the third coil on the primary side is electrically connected to the third input terminal through a third instrument current transformer. According to claim 5,
A power receiving transformer wherein the line-to-line voltage or phase-to-phase voltage output from the first output terminal, the second output terminal, and the third output terminal is higher than the transformation voltage. According to claim 1,
If the first connection is a Y connection and the second connection is a Y connection,
The first terminal of the first coil on the primary side is electrically connected to the first input terminal, the first terminal of the second coil on the primary side is electrically connected to the second input terminal, and the first terminal of the third coil on the primary side is electrically connected to the third input terminal. It is electrically connected to the input terminal, and the second terminal of the first coil of the primary side, the second terminal of the second coil of the primary side, and the second terminal of the third coil of the primary side are connected to the first neutral point,
The first terminal of the first coil on the secondary side is electrically connected to the first output terminal, the first terminal of the second coil on the secondary side is electrically connected to the second output terminal, and the first terminal of the third coil on the secondary side is electrically connected to the third output terminal. It is electrically connected to an output terminal, and the second terminal of the first coil on the secondary side, the second terminal of the second coil on the secondary side, and the second terminal of the third coil on the secondary side are connected to a second neutral point,
The first connection wire is a first wire connecting a first tab disposed on the first coil of the secondary side and the P1 terminal of the relay terminal, and a second tab disposed on the second coil of the secondary side ( a second wire connecting a tap) and the P2 terminal of the relay terminal, a third wire connecting a third tap disposed on the third coil of the secondary side and the P3 terminal of the relay terminal, and the second neutral point. and a fourth wiring connecting the P0 terminal of the relay terminal. According to claim 8,
The first terminal of the first coil on the primary side is electrically connected to the first input terminal through a first instrument current transformer,
The first terminal of the second coil on the primary side is electrically connected to the second input terminal through a second instrument current transformer,
A power receiving transformer wherein the first terminal of the third coil on the primary side is electrically connected to the third input terminal through a third instrument current transformer. According to claim 8,
A power receiving transformer wherein the line-to-line voltage or phase-to-phase voltage output from the first output terminal, the second output terminal, and the third output terminal is higher than the transformation voltage. According to claim 1,
A power receiving transformer including a second connection wire that supplies transformed currents of the plurality of instrument current transformers to the relay terminal. According to claim 11,
The second connection wiring is
A fifth wire connecting the first output terminal of the first instrument current transformer and the 1S terminal of the relay terminal, a sixth wire connecting the first output terminal of the second instrument current transformer and the 2S terminal of the relay terminal, and a third wire. A seventh wire connecting the first output terminal of the instrument current transformer and the 3S terminal of the relay terminal, an eighth wire connecting the second output terminal of the first instrument current transformer and the 1L terminal of the relay terminal, and the second wire. A number including a 9th wire connecting the second output terminal of the instrument current transformer and the 2L terminal of the relay terminal and a 10th wire connecting the 2nd output terminal of the third instrument current transformer and the 3L terminal of the relay terminal. Dedicated transformer. According to claim 1,
The KEPCO meter is a power receiving transformer including a maximum demand meter (DM), a reactive power meter (VAR), a reactive power meter (VARH), a total power meter (WH), or a combination thereof. A high-voltage switchgear facility including the power receiving transformer disclosed in claim 1.