Method and device for energizing voltage source converter of high-voltage DC converter station
By using D-wiring on the sub-side of the converter transformer of the high-voltage DC converter station and closing the circuit breaker in a specific sequence, only the resistor is connected to one or two phases, the problem of large footprint of the traditional VSC power-on solution is solved, and efficient utilization of land resources and cost reduction is achieved.
Patent Information
- Application Number
- CN202410168527.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-05
- Publication Date
- 2025-08-05
AI Technical Summary
The voltage source converter (VSC) power-on solution of traditional high-voltage DC converter stations covers a large area, resulting in high construction costs, especially in areas with tight land resources.
The sub-side of the converter transformer with D-wired is closed in a specific order with the three-phase AC circuit breaker connected to only one or two phases to reduce the footprint.
By optimizing the VSC power-on process, the land area is reduced and the construction cost is reduced, and it is suitable for areas with tight land resources.
Smart Images
Figure CN120433288A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of power transmission systems for transmitting or receiving high-voltage direct current (HVDC) power, and more particularly to a method and apparatus for starting a voltage source converter of a HVDC converter station, and the HVDC converter station. Background Art
[0002] High voltage direct current (HVDC) power transmission systems have become an option over their high voltage alternating current (HVAC) competitors for transmitting large amounts of electrical power due to their lower losses and costs.
[0003] At each end of an HVDC power transmission system, a converter station can be used to convert alternating current (AC) to direct current (DC) electrical power. With recent advances in semiconductor technology, voltage source converters (VSCs) using, for example, insulated gate bipolar transistors (IGBTs) as switching devices have become popular because they are self-commutated and have no risk of commutation failure.
[0004] Before a VSC begins operation, it must first be powered on so that its internal electronic components and control systems can function properly. In traditional VSC power-on solutions, even if a point-on-wave (PoW) function is implemented in the AC circuit breaker, the solution still occupies a large amount of space, for example, 10,000 square meters, due to the use of three-phase pre-insertion resistors (PIRs) and bypass circuit breakers. This results in a large footprint for HVDC converter stations including VSCs, which significantly increases construction costs for densely populated areas. For example, my country has a large number of ultra-high voltage direct current (UHVDC) converter stations, such as 800kV UHVDC. Due to limited land resources, the State Grid Corporation of China (SGCC) hopes to minimize the footprint of HVDC converter stations including VSCs to reduce construction costs. Summary of the Invention
[0005] To at least partially improve or resolve the aforementioned issues, the present disclosure intends to provide at least one method for energizing a voltage source converter of a high-voltage direct current (HVDC) converter station. Furthermore, the present disclosure relates to an apparatus for energizing a voltage source converter of a high-voltage direct current (HVDC) converter station, and a high-voltage direct current (HVDC) converter station including the apparatus.
[0006] Therefore, according to a first aspect of the present disclosure, there is provided a method for energizing a voltage source converter (VSC) of a high voltage direct current (HVDC) converter station, wherein the HVDC converter station comprises:
[0007] - A converter transformer comprising:
[0008] a primary side comprising a first primary side phase, a second primary side phase and a third primary side phase, the first primary side phase, the second primary side phase and the third primary side phase being electrically connectable to a first phase, a second phase and a third phase of an alternating current (AC) power source, respectively, wherein
[0009] A first pre-insertion resistor PIR is connected between the first primary side phase of the converter transformer and the first phase of the AC power source; and
[0010] No PIR is connected between the third primary side phase of the converter transformer and the third phase of the AC power source; and
[0011] - at least one secondary side having a D connection, one of the at least one secondary side comprising a first secondary side phase, a second secondary side phase and a third secondary side phase, the first secondary side phase, the second secondary side phase and the third secondary side phase
[0012] The secondary side phases can be electrically connected to the three phases of the AC side of the VSC respectively; and
[0013] an AC circuit breaker disposed between the converter transformer and the AC power source and operable to connect or disconnect an electrical connection between each of the first primary-side phase, the second primary-side phase, and the third primary-side phase of the converter transformer and the corresponding first phase, second phase, and third phase of the AC power source;
[0014] The method includes, by operating the AC circuit breaker, performing the following steps in sequence to energize the VSC:
[0015] - electrically connecting a first primary side phase of the converter transformer to a first phase of the AC power source;
[0016] - electrically connecting a second primary side phase of the converter transformer to a second phase of the AC power source; and
[0017] - electrically connecting the third primary side phase of the converter transformer to the third phase of the AC power source.
[0018] According to a second aspect of the present disclosure, there is provided an apparatus for energizing a VSC of an HVDC converter station, wherein an AC circuit breaker of the apparatus is configured to operate according to the method of the present disclosure.
[0019] According to a third aspect of the present disclosure, a high voltage direct current (HVDC) converter station is provided, comprising at least one VSC; and an apparatus for energizing the VSC of the HVDC converter station according to the present disclosure.
[0020] The above is a summary of this application, which may contain simplifications, generalizations, and omissions of details. Those skilled in the art will appreciate that this section is merely illustrative and is not intended to limit the scope of this application in any way. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above and other features of the present application will be more fully understood by the following description and the appended claims, taken in conjunction with the accompanying drawings. It will be understood that these drawings depict only several embodiments of the present application and should not be considered as limiting the scope of the present application. By using the accompanying drawings, the present application will be more clearly and more fully illustrated.
[0022] Figure 1 FIG. 1 is a schematic diagram of an apparatus for energizing a VSC of an HVDC converter station according to the related art.
[0023] Figure 2 FIG. 1 is a schematic diagram of an apparatus for energizing a VSC of an HVDC converter station according to an embodiment of the present disclosure.
[0024] Figure 3 Schematic diagram of Y / D connection of a converter transformer according to one embodiment of the present disclosure.
[0025] Figure 4(a) and Figure 4(b) are respectively Figure 2 The device shown is a simulation diagram of the voltages on the primary and secondary sides of a Y / D-connected converter transformer when only one phase on the primary side is closed.
[0026] Figure 5(a) and Figure 5(b) are respectively Figure 2 The device shown is a simulation diagram of the voltages on the primary and secondary sides of the Y / D-connected converter transformer when the other phase on the primary side is further closed.
[0027] Figure 6 FIG. 1 is a schematic diagram of an apparatus for energizing a VSC of an HVDC converter station according to another embodiment of the present disclosure.
[0028] Figure 7 4 is a flow chart of a method for energizing a VSC of an HVDC converter station according to an embodiment of the present disclosure.
[0029] Figure 8(a) to Figure 8(d) Shows the use of Figure 2 Simulation diagram of current and voltage for energizing a VSC using the device shown.
[0030] Figure 9(a) to Figure 9(d) Shows the use of Figure 6 Simulation diagram of current and voltage for energizing a VSC using the device shown. DETAILED DESCRIPTION
[0031] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, like reference numerals generally refer to like parts, unless the context clearly dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be employed, and other changes may be made, without departing from the spirit or scope of the subject matter of the present application. It will be understood that various configurations, substitutions, combinations, and designs of the various forms of the present application generally described herein and illustrated in the drawings may be made, all of which are intended to form a part hereof.
[0032] At each end of an HVDC power transmission system, a converter station is used to convert AC and DC power. Before a converter station, equipped with a voltage source converter (VSC), can begin operation, it must first be powered on to enable its internal electronic components and control systems to function properly.
[0033] In related technologies, such as Figure 1 As shown, an HVDC converter station includes a VSC 100'. The HVDC converter station (or VSC 100') includes an AC side 110' and a DC side 120'. The HVDC converter station (or VSC 100') is connected to an AC power source 400' on its AC side 110' via a converter transformer 200'. The AC power source may be, for example, a power control center (PCC). The HVDC converter station (or VSC 100') is connected to a DC transmission system on its DC side 120'.
[0034] A three-phase AC circuit breaker 300' is provided between the converter transformer 200' and the AC power source 400'. It should be understood that the three phases of the three-phase AC circuit breaker 300' are connected between the three phases of the converter transformer 200' and the three phases of the AC power source 400' (or DC power source), respectively, thereby controlling the on / off switching between the three phases of the converter transformer 200' and the three phases of the AC power source 400' (or DC power source). To ensure successful power-up and proper operation of the VSC 100', three sets of pre-insertion resistors (PIRs) 310' and bypass circuit breakers are also provided in the related art. These three sets of PIRs 310' and bypass circuit breakers are respectively provided between the three phases connected to the three-phase AC circuit breaker 300' and the converter transformer 200'. When closing the three-phase AC circuit breaker 300' to energize the VSC 100', all three PIRs are connected to the converter transformer 200' to minimize the overall impact on the transmission system when the VSC is energized. This serves multiple purposes, such as ensuring compliance with power quality / grid regulations, including limiting inrush / harmonic currents and reducing AC source voltage disturbances and frequency excursions. Furthermore, if the VSC is a modular multilevel converter (MMC) comprised of cells or submodules (SMs), using PIRs on all three phases also balances the MMC cell voltages. After the VSC 100' is successfully energized, the three PIRs can be bypassed using the bypass circuit breaker.
[0035] However, the use of PIRs and bypass breakers takes up a lot of space, for example, up to 10,000 square meters in UHVDC projects. This makes the HVDC converter station including the VSC occupy a large area.
[0036] To at least partially improve or resolve the above-mentioned problems, the present disclosure provides a method and apparatus for energizing a voltage source converter of a high-voltage direct current (HVDC) converter station. In particular, the present disclosure proposes that by adopting a D-connection (i.e., delta connection) on at least one secondary side of the converter transformer and closing the three-phase AC circuit breakers sequentially in a certain order, it is possible to connect a PIR and a bypass circuit breaker to only one or two phases of the converter transformer, that is, to eliminate the PIR and bypass circuit breaker on one or two phases, thereby reducing the footprint. To successfully energize the voltage source converter, the closing order of the three-phase AC circuit breakers must be such that the phases connected to the PIR and bypass circuit breaker are closed first, and the phases without the PIR and bypass circuit breaker are closed last.
[0037] Exemplary embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.
[0038] Figure 2A schematic diagram illustrates an apparatus for energizing a VSC of an HVDC converter station according to one embodiment of the present disclosure. The HVDC converter station includes a VSC 100. The HVDC converter station (or VSC 100) includes an AC side 110 and a DC side 120. The HVDC converter station (or VSC 100) is connected to an AC power source 400 on its AC side 110 via a converter transformer 200. It should be understood that in some embodiments, the AC power source 400 may be a power control center (PCC). The HVDC converter station (or VSC 100) is connected to a DC transmission system on its DC side 120.
[0039] Further references Figure 2 The converter transformer 200 includes a primary side 210. The primary side 210 includes a first primary side phase A, a second primary side phase B, and a third primary side phase C. The first primary side phase A, the second primary side phase B, and the third primary side phase C can be electrically connected to a first phase, a second phase, and a third phase of an AC power source 400, respectively.
[0040] exist Figure 2 In the embodiment, the converter transformer 200 further includes a secondary side 220. The secondary side 220 includes a first secondary side phase a, a second secondary side phase b, and a third secondary side phase c. The first secondary side phase a, the second secondary side phase b, and the third secondary side phase c are electrically connected to the three phases of the AC side of the VSC 100, respectively. In other embodiments, the converter transformer may further include multiple secondary sides. For example, the converter transformer may include a primary side and two secondary sides.
[0041] Continue to refer Figure 2 , in order to control the VSC 100 to access the AC power source to power on the VSC 100, Figure 2 The device shown also includes an AC circuit breaker 300, which is arranged between the converter transformer 200 and the AC power source 400 and is capable of operating to connect or disconnect the electrical connection between each of the first main side phase A, the second main side phase B and the third main side phase C of the converter transformer 200 and the corresponding first phase, second phase and third phase of the AC power source 400.
[0042] For the three-phase connection of the converter transformer 200 and the AC power source 400, unlike the related art which includes three sets of pre-insertion resistors PIR and bypass switches, the three-phase connection of the converter transformer 200 and the AC power source 400 is different from the related art which includes three sets of pre-insertion resistors PIR and bypass switches. Figure 2The illustrated device only has a first pre-insertion resistor (PIR) 310 and a bypass switch for bypassing the first PIR 310 connected between the first primary-side phase A of the converter transformer 200 and the first phase of the AC power source 400. On the other two phases—between the second primary-side phase B of the converter transformer 200 and the second phase of the AC power source 400, and between the third primary-side phase C of the converter transformer 200 and the third phase of the AC power source 400—no PIR or bypass switch is connected, effectively reducing the footprint. It should be understood that the bypass switch is merely an example. Any device capable of bypassing a PIR is applicable.
[0043] It should be noted that in order to successfully power on the VSC while reducing the number of PIRs, the converter transformer according to the present disclosure needs to include at least one secondary side with a D connection. Figure 2 In this embodiment, the secondary side 220 uses a D-connection. In an embodiment comprising one primary side and two secondary sides, at least one of the two secondary sides needs to use a D-connection. For example, the converter transformer may use a Y / Y / D connection. In this case, the VSC can be electrically connected to either a Y-connected secondary side or a D-connected secondary side.
[0044] It is important for the converter transformer according to the present disclosure to include at least one secondary side with D connection to energize the VSC. Figure 3 The converter transformer shown adopts Y / D connection as an example and is further explained in combination with the simulation results shown in FIG4 .
[0045] like Figure 3 As shown, converter transformer 200 employs a Y / D connection. That is, primary side 210 is connected to an AC power source (or PCC) using a Y connection, while secondary side 220 is connected to a D connection and is not yet connected to any load. When an AC voltage is applied to the Y-connected primary side 210, a corresponding voltage is observed on the D-connected secondary side 220.
[0046] 4( a ) shows the simulation results of the three-phase voltages on the Y-connected primary side 210 when only the first primary side phase A of the primary side 210 is closed, while FIG4( b ) shows the corresponding three-phase voltages observed on the D-connected secondary side 220 .
[0047] As shown in FIG4( a ), when only the first main side phase A of the main side 210 is closed (i.e., the AC circuit breakers of the second main side phase B and the third main side phase C remain open), due to the application of Kirchhoff's law, it can be seen that the second main side phase B and the third main side phase C also obtain voltage, and the peak voltage of the second main side phase B and the third main side phase C relative to the ground is half that of the first main side phase A, and the phase is shifted by 180 degrees.
[0048] Accordingly, as shown in FIG4( b ), on the D-connected secondary side 220, the first secondary side phase a receives a relatively high voltage. Similarly to the Y-connected primary side 210, the second secondary side phase b and the third secondary side phase c also receive voltages. The peak voltages of the second secondary side phase b and the third secondary side phase c relative to ground are half that of the first secondary side phase a, and are 180 degrees out of phase with each other.
[0049] It can be seen that by closing only one phase of the primary side 210 of the Y connection, a relatively high voltage can be obtained on the secondary side 220 of the D connection.
[0050] Referring now to Figures 5(a) and 5(b), we will examine the voltages on the primary side 210 and secondary side 220 when the second primary side phase B of the primary side 210 is further closed while the third primary side phase C remains open. As shown in Figure 5(a), after the second primary side phase B of the primary side 210 is further closed, the voltages on the second and third primary side phases B and C of the Y-connected primary side increase to the same level as the first primary side phase A, meaning that all three phases reach their full amplitude. As shown in Figure 5(b), due to the characteristics of the D-connection, the voltages on the three phases of the D-connected secondary side change in the same manner as the Y-connected primary side, achieving their full amplitudes.
[0051] As can be seen, one of the main advantages of using D-connection is its high fault tolerance. This is typically used at lower voltage levels, such as the typical 35kV AC distribution level. Corresponding to the third primary-side phase C, which is still closed on the primary side, even if one input power line is de-energized (e.g., a fuse blows), the secondary side can still obtain fully symmetrical voltages on all three phases. This is why the converter transformer according to the present disclosure includes at least one secondary side that uses D-connection. Because at least one secondary side uses D-connection, when the two phases on the primary side are closed, all three phases of the VSC will obtain full-amplitude symmetrical voltages.
[0052] Figure 6 A schematic diagram of an apparatus for energizing a VSC of an HVDC converter station according to another embodiment of the present disclosure is shown. Figure 6 The device shown is Figure 2 The device has the same structure as in Figure 6 In the illustrated arrangement, the second PIR 320 and its bypass arrangement are further disposed between the second primary side phase B of the converter transformer 200 and the second phase of the AC power source 400 .
[0053] Based on the use of D-connection on at least one secondary side of a converter transformer, this disclosure proposes a method for closing three-phase AC circuit breakers in a specific sequence, enabling successful energization of the VSC while connecting only one or two phases of the converter transformer with a PIR and bypass device. The closing sequence of the three-phase AC circuit breakers must ensure that the phases connected to the PIR and bypass breaker are closed first, followed by the phases without PIR and bypass breaker devices.
[0054] In use Figure 2 The arrangement shown (ie, the first PIR 310 is connected only between the first primary side phase A of the converter transformer 200 and the first phase of the AC power source 400) or Figure 6 On the basis of the arrangement shown (ie, the second PIR 320 and its bypass arrangement are further arranged between the second primary side phase B of the converter transformer 200 and the second phase of the AC power source 400), Figure 7 A method 700 for energizing a VSC of an HVDC converter station according to an embodiment of the present disclosure is shown. The method 700 includes operating the AC circuit breaker 300 to perform the following steps in sequence to energize the VSC 100:
[0055] - Step S710: electrically connecting the first primary side phase A of the converter transformer 200 to the first phase of the AC power source 400;
[0056] - Step S720: electrically connecting the second primary side phase B of the converter transformer 200 to the second phase of the AC power source 400; and
[0057] Step S730 : electrically connecting the third primary side phase C of the converter transformer 200 to the third phase of the AC power source 400 .
[0058] In use Figure 2 When the apparatus is shown (i.e., the first PIR 310 is connected only between the first main side phase A of the converter transformer 200 and the first phase of the AC power source 400), the method 700 further includes: after electrically connecting the first main phase A of the converter transformer 200 to the first phase of the AC power source 400, bypassing the first PIR 310 in the electrical connection between the first main phase A of the converter transformer 200 and the first phase of the AC power source 400.
[0059] It should be understood that the first PIR 310 may be bypassed after the first main phase A of the converter transformer 200 is electrically connected to the first phase of the AC power source 400 and before the second main side phase B of the converter transformer 200 is electrically connected to the second phase of the AC power source 400. Bypassing the first PIR 310 may also be delayed.
[0060] Using the above method, the VSC power-on process includes:
[0061] In response to bypassing the first PIR 310 in the electrical connection between the first main phase A of the converter transformer 200 and the first phase of the AC power source 400, the first secondary side phase a and the second secondary side phase b of the converter transformer 200 are charged to a predetermined voltage, and the third secondary side phase c of the converter transformer 200 is charged to half of the predetermined voltage;
[0062] - in response to electrically connecting the second primary side phase B of the converter transformer 200 to the second phase of the AC power source 400, the third secondary side phase c of the converter transformer 200 is charged to the same voltage as the first secondary side phase a and the second secondary side phase b; and
[0063] In response to electrically connecting the third primary side phase C of the converter transformer 200 to the third phase of the AC power source 400 , an AC current is formed in the third primary side phase C of the converter transformer 200 .
[0064] Figure 8(a) to Figure 8(d) Shows the use Figure 2 The device shown is a current and voltage simulation diagram for powering up a VSC, where a Y / D connected converter transformer is connected to a VSC based on an MMC half-bridge submodule topology. Figure 8(a) to Figure 8(d) The current changes of the PCC connected to the primary side of the converter transformer; the current changes of the VSC connected to the secondary side of the converter transformer; the voltage changes of the VSC bus; and the total unit voltage changes of the 6 MMC bridge arms in the VSC are shown respectively.
[0065] like Figure 8(a) to Figure 8(d) As shown, the power-on process is as follows:
[0066] - At 0.1 seconds, the first main side phase A is closed at the voltage peak, and the first PIR 310 is provided in the circuit of the first main side phase A;
[0067] At 0.41 seconds, the first PIR 310 is bypassed. In response to the bypassing of the first PIR 310, the MMC bridge arm submodule cell voltages in phases A and B of the VSC are charged to relatively high levels, while the charged voltage of phase C is exactly half of that of phases A and B.
[0068] At 0.61s, the second main side phase B is closed at the voltage peak. No PIR is provided in the circuit of the second main side phase B. In response to the closing of the second main side phase B at the voltage peak, phase C of the VSC is quickly charged to the same voltage as phases A and B.
[0069] At 0.71 seconds, the third main phase C closes at the voltage peak. No PIR is present in the circuit of the third main phase C. As expected, the VSC cell voltage does not continue to rise. Current begins flowing through the third main phase C of the converter transformer.
[0070] This power-on solution requires only a single PIR circuit, resulting in well-controlled and stable power-on, keeping the VSC current below 2.5kA. This power-on method is particularly suitable for areas with limited land resources.
[0071] In use Figure 6 When the apparatus shown in FIG. 7 is used (i.e., the second PIR 320 and the bypass device thereof are further disposed between the second primary side phase B of the converter transformer 200 and the second phase of the AC power source 400), the method 700 further includes: after electrically connecting the second primary side phase B of the converter transformer 200 to the second phase of the AC power source 400, performing the following steps in sequence or simultaneously:
[0072] - bypassing the first PIR 310 in the electrical connection between the first main phase A of the converter transformer 200 and the first phase of the AC power source 400; and
[0073] - Bypassing the second PIR 320 in the electrical connection of the second main phase B of the converter transformer 200 and the second phase of the AC power source 400 .
[0074] It should be understood that the first PIR 310 and the second PIR 320 can be bypassed simultaneously, but bypassing them sequentially can make the overall power-up and cell voltage build-up smoother.
[0075] Using the above method, the power-on process of the VSC includes: in response to electrically connecting the first primary side phase A of the converter transformer 200 to the first phase of the AC power source 400 and electrically connecting the second primary side phase B of the converter transformer 200 to the second phase of the AC power source 400, the first secondary side phase a, the second secondary side phase b and the third secondary side phase c of the converter transformer 200 are charged equally at the same time.
[0076] Figure 9(a) to Figure 9(d) Shows the use of Figure 6 The device shown is a current and voltage simulation diagram for powering up a VSC, where a Y / D connected converter transformer is connected to a VSC based on an MMC half-bridge submodule topology. Figure 9(a) to Figure 9(d) The current changes of the PCC connected to the primary side of the converter transformer; the current changes of the VSC connected to the secondary side of the converter transformer; the voltage changes of the VSC bus; and the total unit voltage changes of the 6 MMC bridge arms in the VSC are shown respectively.
[0077] like Figure 9(a) to Figure 9(d) As shown in the figure, the power-on process is as follows:
[0078] At 0.1 seconds, the first primary phase A closes at the voltage peak, and the second primary phase B closes 120° (6.67 ms) later. A first PIR 310 is provided in the circuit of the first primary phase A, and a second PIR 320 is provided in the circuit of the second primary phase B. In response to the closing of the first primary phase A at the voltage peak and the closing of the second primary phase B 120° (6.67 ms) later, the three phases of the VSC are energized simultaneously and equally, as the VSC is connected to the secondary side of the D-connected converter transformer. However, since the third primary phase C has not yet closed, the active power drawn from the AC power source is asymmetrical (only phases A and B).
[0079] - At 0.41 seconds, the first PIR 310 is bypassed;
[0080] - At 0.61 seconds, the second PIR 320 is bypassed. Bypassing in sequence can make the overall power-on and unit voltage establishment more stable;
[0081] At 0.81 s, the third main side phase C is closed at the voltage peak, and no PIR is provided in the circuit of the third main side phase C. As expected, there is almost no change in the current and voltage simulation graphs.
[0082] Although the above power-up scheme only involves two PIRs, the power-up process is essentially as smooth as with three PIRs. Compared to the case with only one PIR, the power-up scheme with two PIRs is smoother and more controllable, making it suitable for applications where the AC power source has stricter disturbance limits.
[0083] In some embodiments, the AC circuit breaker 300 can be operated by phase selection closing PoW to implement the following operations:
[0084] - electrically connecting the first primary side phase A of the converter transformer 200 to the first phase of the AC power source 400 at a first predetermined point on the voltage waveform of the first phase of the AC power source 400;
[0085] electrically connecting the second primary side phase B of the converter transformer 200 to the second phase of the AC power source 400 at a second predetermined point on the voltage waveform of the second phase of the AC power source 400; and
[0086] At a third predetermined point on the voltage waveform of the third phase of the AC power source 400 , electrically connecting the third primary side phase C of the converter transformer 200 to the third phase of the AC power source 400 .
[0087] In a preferred embodiment, the first predetermined point on the voltage waveform, the second predetermined point on the voltage waveform, and / or the third predetermined point on the voltage waveform are peak voltage points of the phases of the AC power source 400 .
[0088] Another aspect of the present disclosure further provides an apparatus for energizing a VSC 100 of an HVDC converter station. The AC circuit breaker is configured to operate according to a method according to an embodiment of the present disclosure.
[0089] In addition, the present disclosure also provides a high-voltage direct current (HVDC) converter station, which includes at least one VSC and an apparatus for energizing the VSC of the HVDC converter station according to an embodiment of the present disclosure.
[0090] Those skilled in the art can understand and implement other variations to the disclosed embodiments by studying the specification, disclosure, drawings, and appended claims. In the claims, the word "comprising" does not exclude other elements and steps, and the indefinite article "a" or "an" does not exclude plurality. In applications according to this application, a single element may perform the functions of several technical features recited in the claims. Any reference signs in the drawings in the claims should not be construed as limiting the scope.
Claims
1. A method for energizing a voltage source converter (VSC) (100) of a high voltage direct current (HVDC) converter station, wherein: The HVDC converter station comprises: - a converter transformer (200), comprising: - a primary side (210), comprising a first primary side phase (A), a second primary side phase (B) and a third primary side phase (C), The first main side phase (A), the second main side phase (B) and the third main side phase (C) can be electrically connected to the first phase, the second phase and the third phase of an AC power source (400), respectively, wherein A first pre-insertion resistor PIR (310) is connected between the first main side phase (A) of the converter transformer (200) and the first phase of the AC power source (400); and No PIR is connected between the third primary side phase (C) of the converter transformer (200) and the third phase of the AC power source (400); and - at least one secondary side (220) having a D connection, one of the at least one secondary side (220) comprising a first secondary side phase (a), a second secondary side phase (b), and a third secondary side phase (c), the first secondary side phase (a), the second secondary side phase (b), and the third secondary side phase (c) being electrically connectable to three phases of the AC side of the VSC (100), respectively; and - an AC circuit breaker (300) provided between the converter transformer (200) and the AC power source (400) and operable to connect or disconnect electrical connections between each of the first primary side phase (A), the second primary side phase (B), and the third primary side phase (C) of the converter transformer (200) and the corresponding first phase, second phase, and third phase of the AC power source (400); The method includes, by operating the AC circuit breaker (300), performing the following steps in sequence to energize the VSC (100): - electrically connecting a first primary side phase (A) of the converter transformer (200) to a first phase of the AC power source (400); - electrically connecting the second primary side phase (B) of the converter transformer (200) to the second phase of the AC power source (400); and - electrically connecting the third primary side phase (C) of the converter transformer (200) to the third phase of the AC power source (400).
2. The method according to claim 1, wherein No PIR is connected between the second primary side phase (B) of the converter transformer (200) and the second phase of the AC power source (400).
3. The method according to claim 2, further comprising: After electrically connecting the first main phase (A) of the converter transformer (200) to the first phase of the AC power source (400), the first PIR (310) is bypassed in the electrical connection between the first main phase (A) of the converter transformer (200) and the first phase of the AC power source (400).
4. The method according to claim 3, wherein: In response to bypassing the first PIR (310) in the electrical connection between the first primary phase (A) of the converter transformer (200) and the first phase of the AC power source (400), the first secondary side phase (a) and the second secondary side phase (b) of the converter transformer (200) are charged to a predetermined voltage, and the third secondary side phase (c) of the converter transformer (200) is charged to half of the predetermined voltage.
5. The method according to claim 4, wherein In response to electrically connecting the second primary side phase (B) of the converter transformer (200) to the second phase of the AC power source (400), the third secondary side phase (c) of the converter transformer (200) is charged to the same predetermined voltage as the first secondary side phase (a) and the second secondary side phase (b).
6. The method according to claim 4, wherein: In response to electrically connecting the third primary side phase (C) of the converter transformer (200) to the third phase of the AC power source (400), an AC current is formed in the third primary side phase (C) of the converter transformer (200).
7. The method according to claim 1, wherein A second pre-insertion resistor PIR (320) is connected between the second primary side phase (B) of the converter transformer (200) and the second phase of the AC power source (400).
8. The method according to claim 7, further comprising: After electrically connecting the second primary side phase (B) of the converter transformer (200) to the second phase of the AC power source (400), the following steps are performed in sequence or simultaneously: - bypassing the first PIR (310) in the electrical connection between the first main phase (A) of the converter transformer (200) and the first phase of the AC power source (400); and - bypassing the second PIR (320) in the electrical connection between the second main phase (B) of the converter transformer (200) and the second phase of the AC power source (400).
9. The method according to claim 8, wherein In response to electrically connecting the first primary side phase (A) of the converter transformer (200) to the first phase of the AC power source (400) and electrically connecting the second primary side phase (B) of the converter transformer (200) to the second phase of the AC power source (400), the first secondary side phase (a), the second secondary side phase (b), and the third secondary side phase (c) of the converter transformer (200) are simultaneously and equally charged.
10. The method according to any one of claims 1 to 9, wherein The AC circuit breaker (300) is operated by phase selection closing PoW, and wherein, electrically connecting the first primary side phase (A) of the converter transformer (200) to the first phase of the AC power source (400) at a first predetermined point on the voltage waveform of the first phase of the AC power source (400); electrically connecting the second primary side phase (B) of the converter transformer (200) to the second phase of the AC power source (400) at a second predetermined point on the voltage waveform of the second phase of the AC power source (400); and The third primary side phase (C) of the converter transformer (200) is electrically connected to the third phase of the AC power source (400) at a third predetermined point on the voltage waveform of the third phase of the AC power source (400).
11. The method according to claim 10, wherein: The first predetermined point on the voltage waveform, the second predetermined point on the voltage waveform and / or the third predetermined point on the voltage waveform are peak voltage points of the phases of the AC power source (400).
12. The method according to any one of claims 1 to 9, wherein The converter transformer (200) has a Y / D connection design or a Y / Y / D connection design.
13. A device for energizing a VSC (100) of an HVDC converter station, comprising: - a converter transformer (200), comprising: - a primary side (210), comprising a first primary side phase (A), a second primary side phase (B) and a third primary side phase (C), The first main side phase (A), the second main side phase (B) and the third main side phase (C) can be electrically connected to the first phase, the second phase and the third phase of an AC power source (400), respectively, wherein A first pre-insertion resistor PIR (310) is connected between the first main side phase (A) of the converter transformer (200) and the first phase of the AC power source (400); and No PIR is connected between the third primary side phase (C) of the converter transformer (200) and the third phase of the AC power source (400); and - at least one secondary side (220) having a D connection, one of the at least one secondary side (220) comprising a first secondary side phase (a), a second secondary side phase (b), and a third secondary side phase (c), the first secondary side phase (a), the second secondary side phase (b), and the third secondary side phase (c) being electrically connectable to three phases of the AC side of the VSC (100), respectively; and - an AC circuit breaker (300) provided between the converter transformer (200) and the AC power source (400) and operable to connect or disconnect electrical connections between each of the first primary side phase (A), the second primary side phase (B), and the third primary side phase (C) of the converter transformer (200) and the corresponding first phase, second phase, and third phase of the AC power source (400); and Wherein, the AC circuit breaker (300) is configured to operate according to the method according to any one of claims 1-12.
14. A high-voltage direct current (HVDC) converter station, comprising: At least one VSC; as well as The device for energizing a VSC (100) of an HVDC converter station according to claim 13.