Transformer for controlling independent active and reactive power flows in transmission line

Abstract

An exemplary transformer includes an exciter unit (EU) and a compensation voltage unit (CVU). The EU includes a three-phase transformer having a parallel Y-connected primary winding. The CVU includes a plurality of series-connected secondary windings having one secondary winding from each phase of the EU and a plurality of on-load tap-changers. Each on-load tap changer is associated with a group of secondary windings, the group of secondary windings including one secondary winding per phase from the EU. Each secondary winding in the group of secondary windings is a same distance from an associated primary winding of the EU. All the secondary windings, the sub-windings between two consecutive taps, and the primary winding have similar heights. The sub-windings can be staggered or not staggered. Each on-load tap changer may vary the number of effective turns of the associated group of secondary windings by connecting to one of the plurality of taps associated with each secondary winding according to the selected operating point.

Description

Technical Field

[0001] This disclosure relates to a transformer, and more specifically, to a transformer that generates a compensation voltage. Background Technology

[0002] In the past, electrical engineering techniques used inductors, capacitors, transformers, and on-load tap changers to implement power flow control. In recent years, power electronics-based solutions have become the preferred approach for power flow control. The cost and complexity of power flow control solutions can vary significantly, ranging from building new transmission lines to more effectively utilizing existing ones. A crucial consideration for any solution is identifying underutilized transmission lines and leveraging their dormancy capabilities, using the most cost-effective and time-tested solutions to increase power flow to the line's thermal limits.

[0003] Power flow control in a line is performed by adjusting the effective line reactance using series-connected capacitors or reactors, or by adjusting the effective phase angle between the voltages at the transmitting and receiving ends of the line. In either case, the active and reactive power flows in the line change simultaneously, meaning that active and reactive power flows cannot be controlled independently.

[0004] Only by using an impedance regulator (IR) to simulate independently adjustable resistance and reactance can independent control of active and reactive power flow in the line be achieved as needed.

[0005] The achievable power flow controller uses a compensation voltage at any phase angle with the line current flowing through it to simulate four-quadrant impedance (-R, +R, X). C and X L The ratio of the compensation voltage to the mains current is the simulated impedance. This compensation voltage exchanges active and reactive power with the line. To allow the exchanged power to flow freely, the compensation voltage is linked to the shunt-series voltage of the same line in the cases of a unified power flow controller based on power electronics, a rotary transformer based on motors, and a SenTransformer based on a transformer / LTC, or to the series-connected voltage in the cases of an inter-line power flow controller based on power electronics or a multi-line SenTransformer based on a transformer / LTC. In special cases, when the compensation voltage and the line current flowing through it are orthogonal, the compensation voltage made by power electronics or motors does not need to be linked to another voltage source. These special cases are equivalent to compensation using capacitors or reactors.

[0006] US Patent 7,835,128 discloses a Distributed Series Reactor (DSR) that inserts the magnetizing inductance of a transformer into the conductor when the conductor current reaches a predetermined value, and removes the magnetizing inductance when the conductor current returns below the predetermined value. The disclosed method inserts the reactor in series with the line and only reduces the power flow in the line. Because capacitors cannot be inserted in series with the line using this method, the system cannot increase the power flow in the line. Furthermore, the system does not implement -R or +R; therefore, it is not an impedance regulator and cannot independently control the active and reactive power flows in the line.

[0007] US Patent 5,198,746 discloses a technique that connects a compensation voltage in series with the line and keeps its phase angle lagging behind or leading the mainstream line current. This method simulates a series capacitor or reactor. By controlling the action, the amplitude of the series compensation voltage is changed to alter the simulated capacitor or reactor. A method for achieving variable amplitude series compensation voltage using a power electronic inverter is proposed. Impedance compensation is based on energy storage on the DC capacitor of the inverter, allowing additional active power to be exchanged with the line on a transient basis. Impedance compensation depends on the rating of the storage device; therefore, its operating duration is finite. For power flow controllers capable of achieving four-quadrant impedance and independently controlling active and reactive power, impedance compensation on a continuous basis is required. The disclosed technique also uses a reactance control method for operating a reactance regulator (RR) such that the series compensation voltage ( The reactance (X) is proportional to the main line current (I), where the simulated reactance (X) seThe proportionality constant is . For this control algorithm to work successfully, a line current must be present. Furthermore, in the reactance control method, the polarity of the reactance is defined before the desired control action occurs. If it is defined as inductive, the most that can be achieved is reducing the line current to slightly below the corresponding uncompensated value. The controller can never bring the line current close to zero because the successful operation of the control algorithm depends on the presence of the line current. If the simulated reactance is defined as capacitive, the line current will increase first. If the simulated capacitive reactance requirement is higher than the line inductive reactance, the effective line reactance becomes capacitive, and the power flow in the line reverses. However, reversing the power flow when the line current is high can cause many problems. During the transition, the line may operate beyond its maximum thermal capacity when the power flow reverses. Furthermore, during the simulation of higher capacitive reactance, there is a point where the line's inductive reactance and the capacitive reactance simulated by the reactance regulator become equal, which can lead to instability in the line's power flow. The reactance control method provides the fundamental characteristics of RR in reducing or increasing the power flow in the line. However, undesirable characteristics of this control method emerge during power flow reversal in the line when the line current is too high and even leads to higher transients. In practical implementations, if the current through the inverter exceeds its rated value, the inverter-based inverter will be bypassed.

[0008] U.S. Patent 5,754,035 discloses a voltage control method that provides all the desired characteristics offered by a reactance control method in terms of power flow in a controlled circuit. Furthermore, the voltage control method provides absolute stability in the power flow, causing the power to approach zero when its flow direction is changed.

[0009] U.S. Patent 9,197,065 discloses a phase angle regulator (PAR) that provides a phase angle adjustment proportional to the line voltage. A series compensation voltage with relative phase angle. The purpose of a PAR (Parking Arrangement) is to adjust the phase shift angle of the line voltage to control the power flow in the line; however, phase angle adjustment cannot independently control the active and reactive power flow in the line. PARs cannot be used... to (remove The relative phase angle (outside of the range of the active and reactive power flows) cannot independently promote active and reactive power flows. Power electronics-based PARs can provide dynamic compensation within milliseconds, such as the power electronics-based impedance regulator (unified power flow controller) demonstrated in 1998 at the Inez substation of a US power company. In contrast, the dynamic performance of PARs is limited by the operating speed of mechanical LTCs, which respond in seconds; however, this level of response time has been accepted in most utility applications for decades.

[0010] A PAR injects a compensation voltage in series with the line, thereby simulating a compensation impedance, which is the ratio of the compensation voltage to the main line current. However, this simulated impedance is not an independently adjustable resistance and reactance; therefore, the PAR cannot independently control the active and reactive power flows in the line, whereas an impedance regulator (IR) provides independent control of the active and reactive power flows in the line as needed.

[0011] US Patent 5,841,267 discloses independent control of active power flow and reactive power flow, enabling the use of motors to generate compensating voltage.

[0012] US Patent 8,054,011 discloses a motor-based independent active and reactive power flow controller. This machine uses a parallel-parallel configuration, which results in a significantly higher rated power and cost compared to an equivalent parallel-series power flow controller.

[0013] Figure 1 illustrates a Sen transformer according to a known embodiment. U.S. Patent Nos. 6,335,613; 6,384,581; 6,396,248; and 6,420,856 disclose a Sen transformer in a parallel-series configuration, used as a general-purpose power flow transformer for compensating power flows in transmission lines. The Sen transformer provides independent control of active and reactive power flows by using a redesigned transformer / LTC technology, employing IR in a low-cost manner. This is because transformer / LTC technology has proven efficient, simple, and reliable in utility applications for decades. The Sen transformer uses three primary windings and nine secondary windings to generate a compensation voltage that modifies the line voltage to a specific amplitude and phase angle, whereas conventional transformers only modify the amplitude of the line voltage, and PAR only modifies the phase angle. Therefore, by using the Sen transformer, active and reactive power flows in the line can be independently regulated to maximize the productive active power flow and minimize the reactive power flow while maintaining line voltage stability.

[0014] Transformers used in power system applications typically fall into two categories: voltage-regulating transformers (VRTs) and phase-angle regulators (PARs). VRTs primarily regulate the amplitude of the line voltage (i.e., an increase or decrease in line voltage) without significantly altering its original phase angle. In symmetrical configurations, PARs primarily regulate the phase angle of the line voltage while its original voltage amplitude remains largely unchanged. In asymmetrical configurations, PARs primarily regulate the phase angle of the line voltage while also increasing its amplitude somewhat.

[0015] Figure 2A and2B A voltage-regulating transformer according to a known embodiment is shown. The VRT can be of two types: (a) as... Figure 2A The autotransformer 202 and (b) shown are as follows Figure 2B The two-winding transformer 204 is shown. Because the transformer is configured to convert electrical energy from one voltage and current level at its input to another voltage or current level at its output, if the primary voltage (V... p ) is applied to a surface with n p On the primary winding of the turns, and the secondary voltage (v s ) in having n s If an induction is generated on the secondary winding of a turn, then an ideal transformer operates according to the following principle:

[0016] (1)

[0017] Depending on the transformer configuration, the output voltage (V) out ) and input voltage (V in The relationship is as follows:

[0018] (2)

[0019] (3)

[0020] Among them, the primary voltage (V p ) is applied to a surface with n p On the primary winding of the turns, and the secondary voltage (v s ) in having n s An induction is formed on the secondary winding of the turns. Input current (i) in ) and output current (i out The relationship is as follows:

[0021] (4)

[0022] (5)

[0023] The principle of maintaining balance between the primary and secondary windings using magnetomotive force, i.e.

[0024] (6)

[0025] exist Figure 2A and Figure 2B In both configurations, it can be verified from equations (2), (3), (4), and (5) that the input power and output power are the same. In other words,

[0026] (7)

[0027] In a two-winding transformer, the primary and secondary voltages are electrically isolated. The induced voltage in the secondary winding is connected in parallel with the circuit. For step-up transformers, This helps to increase the output voltage from the generator before sending electrical energy through high-voltage AC transmission lines. For step-down transformers, This helps to reduce the voltage of the transmission line before using it at various lower voltages required by the load. When At this stage, the primary and secondary voltages and the primary and secondary currents are the same, and the transformer is used as an isolation transformer because the primary and secondary voltages are electrically isolated. In autotransformers and two-winding transformers, the number of active turns in the secondary winding varies with the use of the LTC.

[0028] Based on equations (1) and (6), it can be written as

[0029] (8)

[0030] This ensures power balance in the primary and secondary windings, because an ideal transformer neither generates nor absorbs power.

[0031] Figure 2A The autotransformer is referred to as having a parallel-series configuration because the excitation (i.e., primary) winding is 206 p Connected to the line in parallel, and the compensating (i.e., secondary) winding 206 s Connected to the line in series. Figure 2B The two-winding transformer is referred to as having a parallel-parallel configuration because the excitation (i.e., primary) winding is 208. p And compensation (i.e., secondary) winding 208 s All are connected to the line in parallel. In a parallel-series configuration, the primary and secondary windings are electrically connected; however, in a parallel-parallel configuration, the primary and secondary windings are electrically isolated.

[0032] Figure 3 A transformer circuit according to a known embodiment is shown. For example... Figure 3 As shown, the transformer circuit 300 may include a voltage regulator 302 and a phase angle regulator 304. The voltage regulator (VR) or autotransformer 302 adjusts the phase angle relative to the line voltage. or A variable-amplitude compensation voltage is connected in series with the line to regulate the line voltage. The phase angle adjuster (PAR) 304 adjusts the phase angle relative to the line voltage. or A variable-amplitude compensation voltage is connected in series with the line to adjust the phase angle of the line voltage. The compensation voltage (V) in the autotransformer 302... 1s As the LTC 306 is in phase with the line voltage ( ) or anomaly ( The compensation voltage in PAR 304 varies, thus regulating the amplitude of the transmission line voltage. As the LTC 308 is orthogonal to the line voltage ( or The phase angle of the transmission line voltage changes accordingly. Figure 3 The two orthogonal compensation voltages are shown—V from autotransformer 302. 1s and from PAR 304 —How can these be combined to generate new compensation voltages with variable amplitude and variable phase angle? The new compensation voltage ( (Not limited to any specific phase angle, such as) , or Due to its variable amplitude and variable phase angle compensation voltage, the line voltage can be modified with varying amplitude and phase angle. Using an autotransformer and PAR to generate two quadrature voltages requires the same compensation voltage from a single unit of a Sen transformer. More hardware is needed.

[0033] Figure 4A and Figure 4B Single-line diagrams and associated phasor diagrams of the Sen transformer according to known embodiments are shown respectively. The Sen transformer 400 combines the functions of an autotransformer and a PAR into a smaller physical package, resulting in a reduction in the amount of hardware required for the autotransformer and PAR separately. Figure 4A As shown, the Sen transformer 400 uses parallel units (exciter units) 402 and series units (compensation-voltage units) 404 to create amplitude ( ) and relative phase angle ( Variable series compensation voltage ( ) to modify from (V s )arrive( The line voltage is controlled, and the amplitude is controlled simultaneously. ) and phase shift angle ( This allows for independent control of active and reactive power flow within the line. For example... Figure 4A and Figure 4B As shown, the Sen transformer 400 passes through at any relative phase angle The variable amplitude compensation voltage ( ) and connected in series with the line to simultaneously adjust the amplitude of the line voltage. ) and phase shift angle ( ).

[0034] Back Figure 1A The Sen transformer includes an exciter unit 102 and a three-phase transformer with Y-connected primary windings (108A, 108B, and 108C). The compensation-voltage unit 104 includes nine secondary windings (three windings in each phase: 106 on the core of phase A). a1 106 a2 and 106 a3 ; 106 on the core of phase B b1 106 b2 and 106 b3 ; 106 on the C-phase core c1 106 c2 and 106 c3 Compensation secondary winding 106 a1 106 a2 106 a3 106 b1 106 b2 106 b3 106 c1 106 c2 and 106 c3 They are assigned at specified intervals in groups based on tap arrangement. The compensation voltage ( ) is determined by selecting the number of turns in a set of secondary windings (when using the LTC 110 associated with that set). The amplitude of ) varies within a specific range, and is relative to the phase angle ( )exist to The voltage varies between these phases. The three-phase transmitting terminal voltage (V) sA V sB and V sC The LTC is applied to the exciter unit 102. The LTC gradually changes its position, and the compensation point is then within the allowable controllable range of the relative phase angle. The interior is discrete.

[0035] LTCs can be grouped as follows:

[0036] For the first three-phase LTC1 106 a1 106 b2 and 106 c3

[0037] For the second three-phase LTC2 106 b1 106 c2 and 106 a3

[0038] For the third three-phase LTC3 106 c1106 a2 and 106 b3 .

[0039] This means that each (106) in the winding a1 106 b2 and 106 c3 ) are tapped with the same number of turns through LTC1; each (106) in the winding b1 106 c2 and 106 a3 ) are tapped through LTC2 with the same number of turns; and each (106) winding c1 106 a2 and 106 b3 ) is tapped with the same number of turns via LTC3. However, 106 a1 -106 b2 -106 c3 Collection, 106 b1 -106 c2 -106 a3 Jihe 106 c1 -106 a2 -106 b3 The number of turns in a cluster can be different from each other.

[0040] By selecting the number of turns in each of the three windings via three LTCs (LTC1, LTC2, and LTC3), and thus the three The amplitude of the phase-shift induced voltage component, the compensation voltage in any phase ( All can be obtained from the three-phase secondary winding set (106 for A-phase compensation). a1 106 b1 and 106 c1 ; 106 used for phase B compensation a2 106 b2 and 106 c2 ; and 106 for C-phase compensation a3 106 b3 and 106 c3 The phasor sum of the voltage induced in the secondary winding is derived from the following equations: The magnitude of the induced voltage (V) in the secondary winding, the voltage (x) at each tap of the LTC, and the number of taps (N) in the LTC are related to the following equations:

[0041] (9)

[0042] Compensation voltage ( ) amplitude ( ) and relative phase angle ( The modified transmitter voltage can be calculated based on the tap associated with a specific phase. ) is by having amplitude ( ) and relative phase angle ( Compensation voltage () ) and transmitting voltage (V s It is generated by series connection. This can be written for phase A as:

[0043] (10)

[0044] or (11)

[0045] in (12)

[0046] or (13)

[0047] in:

[0048] V a1 V b1 and V c1 It is the active voltage in the series compensation windings (a1, b1, and c1) of phase A.

[0049] k a1 = 0.05, k b1 = 0 and k c1 = 0.20 is the active turns ratio of any chosen secondary series compensation winding and corresponding primary winding in phase A.

[0050] It is the amplitude of the series compensation voltage in phase A, and

[0051] It is the relative phase angle of the series compensation voltage in phase A.

[0052] Figures 5A to 5F Several single-phase transformers according to known embodiments are shown. Figures 5A to 5B Each single-phase transformer in the diagram is an ideal transformer, in which an alternating current (AC) supply voltage is applied at the input terminal or primary winding, resulting in an alternating current flowing in the primary winding. The primary current (i...) p ) generates AC primary magnetic flux ( According to Faraday's law of induction, the primary voltage (V) p ), primary magnetic flux ( ) and the number of turns in the primary winding (n) p Related to ), as shown below

[0053] (14)

[0054] In reality, an ideal transformer does not exist because the primary magnetic flux ( A portion of (which is called primary leakage flux) ()) does not flow through the magnetic core. For example Figure 5C As shown, the remaining portion is called mutual magnetic flux ( ).

[0055] like Figure 5D As shown, the difference between the two voltages—the primary voltage (V) p ) and the modified primary voltage ( —represented as primary leakage reactance (X) lp The voltage (v) on ) lp To account for primary leakage flux ( Before the ideal transformer operates, the equivalent primary leakage reactance (X) within the transformer is considered. lp It is a part of the excitation primary voltage on the ).

[0056] The primary winding acts as the load of the power source. The secondary winding acts as the power source for the load. When the secondary winding supplies power to the load, the polarity of the current in the secondary winding will cause the secondary current (i) to flow through the load. s The magnetic flux generated and the mutual magnetic flux ( Conversely. To maintain the same interconnection, when the secondary current (i) s When ) increases, the primary current (i p ) will also increase. For example Figure 5E As shown, the secondary magnetic flux that does not flow through the magnetic core ( A portion of this is referred to as mutual magnetic flux ( Conversely, secondary leakage flux ( ).

[0057] The difference between the two voltages — the modified secondary voltage ( ) and secondary voltage (V s —represented as secondary leakage reactance (X) ls voltage (v) on ) 1s To account for secondary leakage flux ( Before the remaining voltage at the output terminals is available, consider the equivalent secondary leakage reactance (X) within the transformer. ls A portion of the induced secondary voltage on ) such as Figure 5F As shown.

[0058] Figures 6A to 6C Three single-phase transformers according to known embodiments are shown. For example... Figure 6A As shown, three single-phase transformers 602A, 602B, and 602C use a three-phase primary voltage (V) pA v pB and v pCExcitation, where the voltage of each phase differs by one phase. The phase angle; in the induced three-phase secondary voltage (v sA v sB and v sC In this process, the voltage of each phase also differs. The phase angle. The number of turns in the primary and secondary windings of each phase are n, respectively. pA and n sA n pB and n sB and n pC and n sC . Figure 6B and Figure 6C The diagram shows the arrangement as a three-phase transformer 604. Figure 6A The single-phase transformer has a core 606 with only one primary winding and one secondary winding on each leg. The leakage reactance in each phase is the same, and the voltage across the leakage reactance in each phase is the same.

[0059] Figure 7A and Figure 7B A three-phase transformer according to another known embodiment is shown. Figure 7A and Figure 7B As shown, each leg of the core has a single primary winding and a secondary winding arranged in a nested configuration, wherein the primary and secondary windings are concentric about each core leg. Even in the nested and concentric arrangement, a primary winding and a secondary winding on each leg of the core will result in the same leakage impedance in each phase, regardless of whether the primary winding is the inner winding placed immediately adjacent to the core and the secondary winding is the outer winding, as... Figure 7A As shown, or the opposite... Figure 7B As shown. Typically, lower voltage windings can be placed close to the core, while higher voltage windings can be placed further away. However, if the windings consist of taps, placing the windings externally may be a better design, regardless of their voltage, because this offers other advantages such as easier access to the taps. Figure 7A and Figure 7B As shown, all primary windings in the transformer have the same internal diameter (ID) and outer diameter (OD). Furthermore, all secondary windings in the transformer have the same ID and OD.

[0060] A Sen transformer can be arranged such that at least multiple secondary windings can be placed on each leg of the core. For this arrangement, special care must be taken to ensure that the leakage impedance in each phase is the same, so that the voltage across the leakage impedance in each phase is balanced; otherwise, the voltages in the three phases at the output will be unbalanced, which is undesirable. Furthermore, the compensation voltages in each of the three phases must have equal amplitudes and be phase-differentiated. The phase angle. Summary of the Invention

[0061] An exemplary transformer for generating a compensation voltage is disclosed, the transformer comprising: an exciter unit; and a compensation voltage unit, the exciter unit comprising three single-phase transformers or a three-phase transformer having parallel Y-connected primary windings, the compensation voltage unit comprising: a plurality of series-connected secondary windings, each comprising one secondary winding from each phase of the exciter unit; and a plurality of on-load tap changers, wherein each on-load tap changer is associated with a set of secondary windings, the set of secondary windings comprising one secondary winding from each phase of the exciter unit, wherein each secondary winding in the set of secondary windings is located at the same distance from the associated primary winding of the exciter unit, wherein all secondary windings, sub-windings between two consecutive taps, and the primary winding have similar heights, the sub-windings may be staggered or not staggered, and wherein each on-load tap changer is configured to: change the effective number of turns of the associated set of secondary windings by connecting to one of the plurality of taps associated with each secondary winding according to a selected operating point.

[0062] An exemplary method for generating a compensation voltage via a transformer having an exciter unit and a compensation voltage unit, comprising three single-phase transformers or a three-phase transformer having parallel Y-connected primary windings, the compensation voltage unit comprising: a plurality of series-connected secondary windings, each including one secondary winding from each phase of the exciter unit; and a plurality of on-load tap changers, each on-load tap changer associated with a set of secondary windings, the set of secondary windings including one secondary winding from each phase of the exciter unit, wherein each secondary winding in the set of secondary windings is located at the same distance from the associated primary winding of the exciter unit, wherein all secondary windings, sub-windings between two consecutive taps, and the primary windings have similar heights, the sub-windings may be staggered or not staggered, the method comprising: selecting an operating point of the transformer; selecting an on-load tap position for each secondary winding in the set of secondary windings associated with each on-load tap changer based on the operating point; and generating a compensation voltage by summing the effective voltages induced in the set of secondary windings for each on-load tap changer. Attached Figure Description

[0063] This patent or application document contains at least one color-drawn drawing. Upon request and payment of the necessary fees, the Patent Office will provide a color-drawn copy of this patent or patent application publication.

[0064] The exemplary embodiments can be best understood from the following detailed description when read in conjunction with the accompanying drawings. The drawings include the following figures:

[0065] Figure 1A and Figure 1BThe Sen transformer and associated phasor diagram in a parallel-series configuration according to a known embodiment are shown.

[0066] Figure 2A and Figure 2B Voltage-regulating transformers according to known embodiments are shown, namely autotransformers and two-winding transformers.

[0067] Figure 3 A transformer circuit according to a known embodiment is shown, which integrates an autotransformer and a phase angle adjuster (asymmetric).

[0068] Figure 4A and Figure 4B Single-line diagrams and associated phasor diagrams of the Sen transformer in a parallel-series configuration according to known embodiments are shown respectively.

[0069] Figure 5A , Figure 5C and Figure 5E The following are examples of known embodiments. Figure 5B , Figure 5D and Figure 5F Multiple single-phase transformers and their equivalent circuit diagrams are shown in the figure.

[0070] Figure 6A Three single-phase transformers according to known embodiments are shown.

[0071] Figure 6B and Figure 6C A three-phase transformer according to a known embodiment is shown.

[0072] Figure 7A The arrangement of the primary winding (closest to the core) and the secondary winding according to a known embodiment is shown.

[0073] Figure 7B The arrangement of the primary and secondary windings (closest to the core) according to a known embodiment is shown.

[0074] Figures 8A to 8P An exemplary winding arrangement of a Sen transformer according to an exemplary embodiment of the present disclosure is shown.

[0075] Figure 9A and Figure 9B The modified transmitter voltage operating point and the corresponding active and reactive power flows (P0) according to exemplary embodiments of the present disclosure are shown. r and Q r Operation points, numbered from 0 to 60.

[0076] Figures 9C to 9AC The maximum active power flow enhancement doubling capability of the Sen transformer according to an exemplary embodiment of the present disclosure is shown.

[0077] Figures 10A to 10E This is a table showing the operating points of a Sen transformer according to exemplary embodiments of the present disclosure.

[0078] Figure 11 Exemplary embodiments according to this disclosure are shown. Exemplary winding layout and ampere-turns distribution at the location.

[0079] Figure 12 Exemplary embodiments according to this disclosure are shown. Exemplary winding layout and ampere-turns distribution at the location.

[0080] Figure 13 Exemplary embodiments according to this disclosure are shown. Exemplary winding layout and ampere-turns distribution at the location.

[0081] Figure 14 Exemplary embodiments according to this disclosure are shown. Exemplary winding layout and ampere-turns distribution at the location.

[0082] Figure 15 Exemplary embodiments according to this disclosure are shown. Exemplary winding layout and ampere-turns distribution at the location.

[0083] Figure 16 Exemplary embodiments according to this disclosure are shown. Exemplary winding layout and ampere-turns distribution at the location.

[0084] Figures 17A to 17AN A Sen transformer with a parallel-parallel configuration and winding arrangement according to an exemplary embodiment of the present disclosure is shown.

[0085] Figures 18A to 18B A series-to-series transformer configuration according to an exemplary embodiment of the present disclosure is shown.

[0086] Figure 19 An exemplary embodiment of the present disclosure is shown, in which a generalized Sen transformer (GST) is configured to generate parallel-compensated voltage and series-compensated voltage in a single cell.

[0087] Figure 20 A method for generating a compensation voltage according to an exemplary embodiment of the present disclosure is shown.

[0088] Other applicable areas of this disclosure will become apparent from the detailed description provided below. It should be understood that the detailed description of exemplary embodiments is for illustrative purposes only and is therefore not intended to limit the scope of this disclosure. Detailed Implementation

[0089] An exemplary embodiment of this disclosure relates to a Sen transformer, wherein the compensation voltage is the phasor sum of three voltages induced in the secondary winding, each voltage originating from a different phase—A, B, or C. The windings are strategically arranged around the legs of the transformer to achieve balanced leakage impedance in each phase. According to the exemplary embodiment described in further detail, all primary windings have the same inner diameter (ID1) and outer diameter (OD1), and substantially similar heights; and all secondary windings and sub-windings between a specified on-load tap changer and a set of two consecutive associated taps have the same inner and outer diameters, and substantially similar heights (i.e., lengths). The sub-windings may or may not be interleaved.

[0090] The exemplary embodiments of this disclosure are based on Figure 8A The Sen transformer 800 can be configured to control independent active and reactive power flows in transmission lines as described herein. The transformer 800 includes an exciter unit 802 and a compensation-voltage unit 804. According to an exemplary embodiment, the exciter unit 802 includes a three-phase transformer having parallel Y-connected primary windings 808A, 808B, and 808C. The compensation-voltage unit 804 includes a plurality of series-connected secondary windings 806 in each phase of the exciter unit 802. The compensation-voltage unit 804 also includes a plurality of on-load tap changers 810, wherein each on-load tap changer 810 is connected to a plurality of secondary windings 806. a1 806 a2 806 a3 806 b1 806 b2 806 b3 806 c1 806 c2 and 806 c3 One of them is associated. Secondary windings can be assigned to three groups of LTC controls, each group having one secondary winding per phase (A, B, and C) from exciter unit 802, and each secondary winding in the group is set to the same load settings. Each secondary winding 806 in the secondary winding groups associated with LTC1, LTC2, and LTC3 a1 806 a2 806 a3 806 b1 806 b2 806 b3 806 c1 806c2 and 806 c3 Located at the same distance from the associated primary windings 808A, 808B, and 808C of the exciter unit 802, and wherein each on-load tap changer is configured to connect to each secondary winding 806 according to the selected operating point. a1 806 a2 806 a3 806 b1 806 b2 806 b3 806 c1 806 c2 and 806 c3 One of the associated taps 810 is used to change the effective number of turns of the associated groups LTC1, LTC2 and LTC3 of the secondary winding.

[0091] Figures 8A to 8P An exemplary winding arrangement of a Sen transformer according to an exemplary embodiment of the present disclosure is shown.

[0092] like Figure 8C As shown, the three (3) exciter windings 808A, 808B, and 808C can be the innermost windings. Figure 8C The winding arrangement can be configured such that all primary windings have the same inner diameter (ID) and outer diameter (OD), and all secondary windings have the same inner diameter ID and outer diameter OD. Furthermore, all windings (i.e., primary and secondary windings) can have substantially the same height or length. Additionally, the secondary windings can be placed on top of the primary windings according to the LTC grouping order. According to an exemplary embodiment, nine (9) compensation windings 806 a1 806 a2 806 a3 806 b1 806 b2 806 b3 806 c1 806 c2 and 806 c3 The secondary winding can be arranged as follows:

[0093] •like Figure 8C , 8D As shown in Figure 8E, the secondary winding 806 is connected to LTC1. a1 806 b2 and 806 c3 They have the same inner diameter (ID2) and outer diameter (OD2) and can be placed on exciter windings 808A, 808B and 808C respectively.

[0094] •like Figure 8C ,8D As shown in 8G, the secondary winding 806 is connected to LTC3. a2 806 b3 and 806 c1 Having the same inner diameter (ID3) and outer diameter (OD3), and can be placed separately in the secondary winding 806. a1 806 b2 and 806 c3 superior.

[0095] •like Figure 8C , 8D As shown in Figure 8F, the secondary winding 806 is connected to LTC2. a3 806 b1 and 806 c2 Having the same inner diameter (OD4) and outer diameter (OD4), and can be placed separately in the secondary winding 806 a2 806 b3 and 806 c1 superior.

[0096] According to an exemplary embodiment, the LTC windings can be concentric with each other, and the exciter windings 808A, 808B, and 808C are at full rating. Three (3) sets of compensation windings (806...) a1 806 b2 and 806 c3 (806) b1 806 c2 and 806 a3 ) and (806 c1 806 a2 and 806 b3 All are rated at full power.

[0097] Figure 8A and Figure 8B The illustration shows an exemplary embodiment of a device having Figure 8A The series compensation voltage generated by the winding arrangement of the Sen transformer 800. Based on Figure 8A The winding arrangement, series compensation voltage ( ) is obtained by measuring the distance between them Three usable induced voltages V are obtained from the exciter phase. a1 V b1 and V c1 And they are constructed by adding them together. Similarly, series compensation voltage ( ) is obtained by measuring the distance between them Three usable induced voltages V are obtained from the exciter phase. a2 V b2 and V c2 And it is constructed by calculating their sum; and the series-compensated voltage ( ) is by coming from the distance The three available induced voltages V of the exciter phase a3 V b3 and V c3 Constructed by addition. By using LTCs (LTC1, LTC2 and LTC3), the corresponding three (3) sets of secondary (i.e., compensation) windings in each phase (806) a1 806 b2 and 806 c3 (806) b1 806 c2 and 806 a3 ) and (806 c1 806 a2 and 806 b3 The effective number of turns of each secondary (i.e., compensation) winding in the composite voltage changes, as do the amplitude and phase angle of the composite voltage.

[0098] In the active secondary winding 806 a1 806 a2 806 a3 806 b1 806 b2 806 b3 806 c1 806 c2 and 806 c3 The magnitude of the induced voltage (V) in one or more of LTCs, the voltage (x) across each tap of LTC1, LTC2, and LTC3, and the number of taps (N) in the LTC are related by the following equation:

[0099] (15)

[0100] According to an exemplary embodiment of this disclosure, the transmitting voltage V s = 1, the allowable amplitude (V) of the induced voltage (V) can be set to 0.2, and the voltage (x) across each tap of the LTC can be 0.05. Therefore, the Sen transformer 800 in each secondary winding 806 a1 806 a2 806 a3 806 b1 806 b2 806 b3 806 c1 806 c2 and 806 c3 It has N = 0.2 / 0.05 or N = 4 taps. Therefore, according to the exemplary configuration of Sen transformer 800, the secondary winding 806 a1 806a2 806 a3 806 b1 806 b2 806 b3 806 c1 806 c2 and 806 c3 Each of the terminals can be tapped at one of tap positions 0, 1, 2, 3, or 4. The selected tap position determines the percentage of the primary voltage, for example, 0%, 5%, 10%, 15%, and 20%, which corresponds to the secondary winding 806. a1 806 a2 806 a3 806 b1 806 b2 806 b3 806 c1 806 c2 and 806 c3 Each of these is an active excitation voltage. The selected tap position also determines the associated secondary winding 806. a1 806 a2 806 a3 806 b1 806 b2 806 b3 806 c1 806 c2 and 806 c3 The degree of contribution to the formation of the compensation voltage. For example, for tap positions 0, 1, 2, 3 or 4, the contribution of the secondary winding to the compensation voltage can be 0.0 (0%), 0.05 (5%), 0.10 (10%), 0.15 (15%) or 0.20 (20%), respectively.

[0101] Figures 8E to 8G The diagram shows the tap positions of on-load tap changers LTC1, LTC2, and LTC3 for any operating point of the Sen transformer 800. For example, the secondary winding associated with the first phase of the exciter unit 802 (i.e., compensation winding 806) a1 A 0.05 pu voltage was applied to the 806 compensation winding. b1 The 0.0 pu voltage was applied and the compensation winding 806 was connected. c1 It is connected to a voltage of 0.20 pu.

[0102] According to an exemplary embodiment of this disclosure, the LTC contacts are moved to a higher tap position (e.g., (i.e., towards the dot) added series-compensated voltage. Primary windings 808A, 808B, and 808C, and secondary winding 806. a1806 a2 806 a3 806 b1 806 b2 806 b3 806 c1 806 c2 and 806 c3 They are considered to have rated voltages of 1 pu and 0.20 pu, respectively. According to the exemplary embodiment described herein, the secondary winding 806... a1 806 a2 806 a3 806 b1 806 b2 806 b3 806 c1 806 c2 and 806 c3 Each of them can have LTC contacts located at every 5% tap position, and includes five taps marked 0 to 4. At tap position 0, each secondary winding is bypassed.

[0103] Figure 8H An exemplary winding arrangement is shown, in which multiple secondary windings for each primary winding are positioned to have the same inner diameter (ID2) and outer diameter (OD2). For example, for phase A of Sen transformer 800, the primary winding 808A is placed as an inner winding on the core leg, and the secondary winding 806... a1 806 a2 and 806 a3 Multiple loops are formed around the primary winding 808A. Each of the secondary windings has the same inner diameter (ID2) and outer diameter (OD2). Similarly, for phase B, the primary winding 808B is the inner winding on the corresponding core leg, and the secondary winding 806... b1 806 b2 and 806 b3 It is an outer winding that forms multiple loops around the primary winding 808B; for phase C, the primary winding 808C is the inner winding on the corresponding core leg, and the secondary winding 806 c1 806 c2 and 806 c3 It is an outer winding that forms multiple loops around the primary winding 808C. Similar to phase A, the secondary windings of phases B and C of the Sen transformer 800 have the same ID and OD.

[0104] Figure 8I and Figure 8J Exemplary embodiments according to this disclosure are shown. Figure 8A The winding arrangement of the Sen transformer includes a third winding. For example... Figure 8IAs shown, the winding arrangement may include multiple nested and concentric windings, such that, for phase A, the third winding 812 is the innermost winding and is placed closest to the core leg, and the three secondary windings 806 a1 806 a2 and 806 a3 It is an outer winding, of which the secondary winding is 806. a3 This is the outermost winding. The primary winding 808A is positioned as the third winding 812 and the inner secondary winding 806. a1 The intermediate winding between. Figure 8J The winding arrangement is similar to Figure 8H The arrangement shown in the figure includes the addition of a third winding 812. (See figure) Figure 8J As shown, the third winding 812 is the innermost winding, and the secondary winding 806 a1 806 a2 and 806 a3 The primary winding 808A is the outermost winding. The primary winding 808A is arranged as the third winding 812 and the secondary winding 806. a1 806 a2 and 806 a3 The intermediate winding between the sets. This secondary winding 806 a1 806 a2 and 806 a3 The primary winding 808A is formed into multiple loops. Although the third winding 812 is shown only relative to phase A, it should be understood that... Figure 8I and Figure 8J The arrangement shown is also applicable to phases B and C of the Sen transformer 800 and can be used for phases B and C of the Sen transformer 800. According to Figure 8I and Figure 8J In an exemplary embodiment, the third winding 812 is delta-connected, meaning it is a delta winding with only one terminal coming out of the transformer for grounding purposes. Furthermore, the third winding 812 does not supply power to any load and is always closed. The third winding remains closed and, when the LTC is in the secondary winding 806... a1 806 a2 806 a3 806 b1 806 b2 806 b3 806 c1 806 c2 and 806 c3This serves as a safety measure during tap switching, allowing the circuit to be open during the transition from one tap position to the next. This condition results in an unbalanced current flow through the secondary winding, which is undesirable. The third winding 812 has zero-sequence impedance, which generates a zero-sequence voltage drop when zero-sequence current flows through it. The third winding 812 is a stabilizing winding that acts as a "bridge" when the transition from one tap position to the next occurs.

[0105] Figure 8K Nine secondary windings (806) in a Sen transformer according to an exemplary embodiment of the present disclosure are shown. a1 806 a2 806 a3 806 b1 806 b2 806 b3 806 c1 806 c2 and 806 c3 The sub-windings between any two tap positions of each secondary winding can be arranged in a non-interleaved manner. For example, the taps of each winding are associated with the sequential arrangement of the tap sequence (i.e., 0 to 3 and 4 to 1).

[0106] Figure 8L Nine secondary windings (806) in a Sen transformer according to an exemplary embodiment of the present disclosure are shown. a1 806 a2 806 a3 806 b1 806 b2 806 b3 806 c1 806 c2 and 806 c3 Any of the following can be arranged in an interleaved manner: Sub-windings between any two tap positions of each secondary winding can be arranged in an interleaved manner. For example, the taps of each winding are associated with a non-sequential arrangement of the tap sequence (i.e., 0, 2, 3, 1 and 2, 4, 3, 1).

[0107] Figure 8M The winding arrangement of a set of three single-phase Sen transformers with a third winding is shown according to an exemplary embodiment of the present disclosure. Figure 8MAs shown, the windings can be arranged such that, for each single-phase transformer, the primary winding 808A, 808B, or 808C is the innermost winding (closest to the core) with ID1 and OD1 on one branch, and the third winding 812 with ID5 and OD5 is also located closest to the core on another branch. For a single-phase transformer with an A-phase excitation voltage, the secondary winding 806... a1 It can be placed on one branch of the exciter winding 808A (closest to the core) to make the winding concentric. Additionally, the secondary winding 806... a2 and 806 a3 It can be placed on the third winding 812 on another branch, where the secondary winding 806 a3 It is the outermost winding, and the three windings are 812 and 806. a2 and 806 a3 Concentric on the same branch. For a single-phase transformer with B-phase excitation voltage, the secondary winding 806 b2 It can be placed on one branch of the exciter winding 808B (closest to the core) to make the windings concentric. Additionally, the secondary winding 806... b3 and 806 b1 It can be placed on the third winding 812 on another branch, where the secondary winding 806 b1 It is the outermost winding, and the three windings are 812 and 806. b3 and 806 b1 Concentric on the same branch. Similarly, for a single-phase transformer with C-phase excitation voltage, the secondary winding 806 c3 It can be placed on one branch of the exciter winding 808C (closest to the core) to make the windings concentric. Additionally, the secondary winding 806... c1 and 806 c2 It can be placed on the third winding 812 on another branch, where the secondary winding 806 c2 The outermost winding, with three windings: 812 and 806. c1 and 806 c2 Concentric on the same branch. Secondary windings connected to the same LTC have the same inner diameter (ID) and outer diameter (OD). For example, based on Figure 8M The winding arrangement shown in the figure includes a secondary winding 806 with ID2 and OD2. a1 806 b2 and 806 c3 It can be connected to LTC1, with secondary windings 806 having ID3 and OD3. a2 806 b3 and 806 c1 It can be connected to LTC3 and has secondary windings 806 with ID4 and OD4. a3 806b1 and 806 c2 It can be connected to LTC2.

[0108] Figure 8N The winding arrangement of a set of three single-phase Sen transformers with a third winding is shown according to an exemplary embodiment of the present disclosure. Figure 8N As shown, the windings can be arranged such that, for each single-phase transformer, the primary winding 808A, 808B, or 808C is the innermost winding (closest to the core) with ID1 and OD1 on one branch, and the third winding 812 with ID5 and OD5 is also located closest to the core on another branch. For a single-phase transformer with an A-phase excitation voltage, the secondary winding 806... a1 806 a2 and 806 a3 Multiple loops are formed around the primary winding 808A. Each of the secondary windings has the same inner diameter (ID2) and outer diameter (OD2). For a single-phase transformer with a B-phase excitation voltage, the secondary winding 806... b2 806 b3 and 806 b1 Multiple loops are formed around the primary winding 808B. Each of the secondary windings has the same inner diameter (ID2) and outer diameter (OD2). Similarly, for a single-phase transformer with a C-phase excitation voltage, the secondary winding 806... c3 806 c1 and 806 c2 Multiple loops are formed around the primary winding 808C. Each of the secondary windings has the same inner diameter (ID2) and outer diameter (OD2).

[0109] Figures 8A-8N An exemplary embodiment of the present disclosure discloses a core-type transformer structure in which transformer windings are wound around a core. It should be understood that the exemplary embodiments of the present disclosure are applicable and can be implemented in shell-type transformer structures in which the core windings are wound around the transformer. Figure 8O and Figure 8P The winding arrangement of a core-type transformer compared to a shell-type transformer, according to exemplary embodiments of the present disclosure, is shown. For example... Figure 8O and Figure 8P As shown, the primary windings 808A, 808B and 808C and the secondary windings 806a, 806b and 806c of the shell-type transformer are enclosed in the transformer core by the outer branches.

[0110] Figure 9A The theoretically possible compensation point for the modified transmitter voltage using Sen transformer 800 is shown. Figure 9B It shows in The corresponding active and reactive power flows at the receiving end across the entire range of the relative phase angle. Figure 9B It is also shown that, in this particular example, the maximum active power flow enhancement at the receiving end is 0.40 pu (from 1 pu to 1.4 pu). Figure 9A The diagram shows that the theoretical circular control area with a fixed compensation voltage of 0.20 pu is hexagonal when using a Sen transformer. A higher number of taps in an LTC brings the compensation points closer together, and vice versa.

[0111] Figure 9A The modified transmitter voltage phasor is also shown. The position of the tip. Figure 9B The active power flow and reactive power flow (P) are illustrated according to exemplary embodiments of the present disclosure. r and Q r Operation point. Figure 9A Each modified transmitter voltage operating point shown corresponds to Figure 9B The power flow operating points in the PQ plane are shown. A subset of operating points (1, 7, 19, 37, 4, 13, 28, and 49) represents the operating points of the voltage regulator (VR). Although the VR operating points are located at relative phase angles... and The relevant straight line exists, but the Sen transformer 800 operating point lies within a two-dimensional operating plane. In practical applications, the expected active and reactive power flows (P0) from 61 possible operating points are considered. r and Q r (Requirement, can) Figure 9A The modified transmitter voltage corresponding to the mapping in the middle ( ) phasor tip, and can be obtained from Figures 10A to 10E Select the appropriate tap position for LTC from the table shown.

[0112] Figure 9C and Figure 9D It shows the target in to Modified transmitter voltage operating point and corresponding active and reactive power flows (P) within a finite relative phase angle range. r and Q r Operation point. The relative phase angle operation at that point provides the maximum active power flow operation point.

[0113] Figure 9E and Figure 9G It shows the target such as Figure 9F The voltage operating point shown is according to an exemplary embodiment of this disclosure. Figure 8A The Sen transformer is configured for use in to Limited relative phase angle operations within a certain range. For example... Figure 9EAs shown, because Sen transformer 800 is configured to... to It operates within a limited relative phase angle range, so the compensation voltage unit 804 can be modified by removing the secondary winding associated with the phase outside the range of relative phase angles of interest. For example, for Figure 9E Compensation voltage unit 804, secondary winding 806 b1 806 c2 and 806 a3 The secondary winding is inactive during operation, or can be omitted or removed from the transformer configuration. Omitting or removing the secondary winding from the transformer, or making it inactive during operation, can result in higher thermal efficiency operation of the Sen transformer 800. Furthermore, omission and / or removal can lead to a reduction in transformer size and cost. Figure 9H and Figure 9I The diagram shows the tap positions of on-load tap changers LTC1 and LTC3 at the maximum active power flow operating point of the Sen transformer 800 (1.4 pu in this particular example). Operation requires only two tap changers because one secondary winding corresponding to a phase outside the finite phase angle range is inactive during operation, or is omitted or removed from the transformer configuration as previously described.

[0114] Figure 9J and Figure 9K It shows the target in Modified transmitter voltage operating point and corresponding active and reactive power flows (P) at the finite relative phase angle operation. r and Q r The operating point provides the minimum active power flow operating point.

[0115] Figure 9L and Figure 9N Exemplary embodiments of the present disclosure are shown for, as Figure 9M The voltage operating point shown is at Finite relative phase angle operation at the point Figure 8A Sen transformer. For example... Figure 9L As shown, because Sen transformer 800 is configured to... The operation is within a finite relative phase angle, so the compensation voltage unit 804 can be modified by removing the secondary winding associated with a phase other than the relative phase angle of interest. For example, for... Figure 9L Compensation voltage unit 804, secondary winding 806 a1 806 c1 806 a2 806 b2 and 806 b3 806 c3The secondary winding is inactive during operation, or can be omitted or removed from the transformer configuration. Omitting or removing the secondary winding from the transformer, or making it inactive during operation, can result in higher thermal efficiency operation of the Sen transformer 800. Furthermore, omission and / or removal can lead to a reduction in transformer size and cost. Figure 9O The diagram shows the tap position of the on-load tap changer LTC2 at the minimum active power flow operating point of the Sen transformer 800 (0.6 pu in this particular example). Because the two secondary windings corresponding to the phases outside the finite phase angle are inactive during operation, or are removed or omitted from the transformer configuration as previously described, only one tap changer needs to be operated.

[0116] Figure 9P and Figure 9Q It shows the target in Modified transmitter voltage operating point for finite relative phase angle operation and corresponding active and reactive power flows (P) r and Q r The operating point provides the maximum active power flow operating point.

[0117] Figure 9R and Figure 9T This illustrates how the secondary winding 806 is reversed when switch 901 is used. b1 806 c2 and 806 a3 When the applied voltage is applied, according to the exemplary embodiments of this disclosure, for... Figure 9S The voltage operating point shown is at Finite relative phase angle operation Figure 8A Sen transformer. For example... Figure 9R As shown, because Sen transformer 800 is configured to... The operation is performed within a finite relative phase angle, so the compensation voltage unit 804 can be modified by removing the secondary winding associated with a phase other than the phase angle of interest. For example, for... Figure 9R Compensation voltage unit 804, secondary winding 806 a1 806 c1 806 a2 806 b2 and 806 b3 806 c3 It is inactive during operation, or can be omitted or removed from the transformer configuration. Figure 9UThe diagram shows the tap position of the on-load tap changer LTC2 at the maximum active power flow operating point of the Sen transformer 800 (1.4 pu in this particular example). Because the two secondary windings corresponding to the phases outside the finite phase angle are inactive during operation or omitted or removed from the transformer configuration as previously described, only one tap changer needs to be operated.

[0118] Figure 9V and Figure 9W It shows the target in to Modified transmitter voltage operating point and corresponding active and reactive power flows (P) within a finite relative phase angle range. r and Q r The operation point, which activates the doubling of the maximum active power flow enhancement function. Figure 9W It is also shown that, in this particular example, the maximum active power flow enhancement at the receiver is 0.80 pu (from 1 pu to 1.8 pu).

[0119] Figure 9X and Figure 9Z Exemplary embodiments of the present disclosure are shown for... Figure 9Y The voltage operating point shown is... Figure 8A The Sen transformer is configured to be in to A finite relative phase angle operation within the range, in which doubling of the maximum active power flow characteristics is activated. Figures 9AA to 9AC The diagram shows the tap positions of on-load tap changers LTC1, LTC2, and LTC3 for the maximum active power flow enhancement operating point (1.8 pu in this particular example) for the Sen transformer 800.

[0120] Figure 11 Exemplary embodiments according to this disclosure are shown. Exemplary winding layout and ampere-turns distribution at the location. For example... Figure 8D and Figure 11 As shown, the primary windings A, B, and C, and the secondary winding 806 associated with LTC1. a1 806 b2 and 806 c3 It is active; LTC2 and LTC3 are set at their minimum tap positions. The magnetomotive force (mmf) is generated in the primary winding and applied across the secondary winding associated with LTC1.

[0121] Figure 12 Exemplary embodiments according to this disclosure are shown. Exemplary winding layout and ampere-turns distribution at the location. For example... Figure 8D and Figure 12 As shown, the primary windings A, B, and C, and the secondary winding 806 associated with LTC1. a1 806 b2 and 806 c3 And the secondary winding 806 associated with LTC3 c1 806 a2 and 806 b3 It is active; LTC2 is set at its minimum tap position. mmf is generated in the primary winding and applied across the secondary windings associated with LTC1 and LTC3.

[0122] Figure 13 Exemplary embodiments according to this disclosure are shown. Exemplary winding layout and ampere-turns distribution at the location. For example... Figure 8D and Figure 13 As shown, the primary windings A, B, and C, and the secondary winding 806 associated with LTC3. c1 806 a2 and 806 b3 It is active; LTC1 and LTC2 are set at their minimum tap positions. mmf is generated in the primary winding and applied across the secondary winding associated with LTC3.

[0123] Figure 14 Exemplary embodiments according to this disclosure are shown. Exemplary winding layout and ampere-turns distribution at the location. For example... Figure 8D and Figure 14 As shown, the primary windings A, B, and C, and the secondary winding 806 associated with LTC3. c1 806 a2 and 806 b3 And the secondary winding 806 associated with LTC2 b1 806 c2 and 806 a3 It is active; LTC1 is set at its minimum tap position. mmf is generated in the primary winding and applied across the secondary windings associated with LTC3 and LTC2.

[0124] Figure 15 Exemplary embodiments according to this disclosure are shown. Exemplary winding layout and ampere-turns distribution at the location. For example... Figure 8D and Figure 15 As shown, the primary windings A, B, and C, and the secondary winding 806 associated with LTC2. b1 806 c2 and 806 a3It is active; LTC1 and LTC3 are set at their minimum tap positions. mmf is generated in the primary winding and applied across the secondary winding associated with LTC2.

[0125] Figure 16 Exemplary embodiments according to this disclosure are shown. Exemplary winding layout and ampere-turns distribution at the location. For example... Figure 8D and Figure 16 As shown, the primary windings A, B, and C, and the secondary winding 806 associated with LTC2. b1 806 c2 and 806 a3 And the secondary winding 806 associated with LTC1 a1 806 b2 and 806 c3 It is active; LTC3 is set at its minimum tap position. mmf is generated in the primary winding and applied across the secondary windings associated with LTC2 and LTC1.

[0126] Figures 17A to 17AN A Sen transformer with a parallel-parallel configuration and winding arrangement according to an exemplary embodiment of the present disclosure is shown. Figure 17A and Figure 17B As shown, the Sen transformer 1700 includes an exciter unit 1702 and a compensation voltage unit 1704 arranged in a parallel-parallel configuration. Figure 17A The Sen transformer 1700, single-phase exciter unit 1702, and 1706 with three compensating windings are shown in a single-phase arrangement. a 1706 b 1706 c The compensation voltage unit 1704. Figure 17C and Figure 17E The three-phase arrangement is shown. Figure 17A The Sen transformer. Figure 17C and Figure 17E The exciter unit 1702 consists of three parallel Y-connected primary windings 1708A, 1708B and 1708C, and the compensation-voltage unit 1704 consists of nine (9) secondary windings (three windings in each phase: 1706 on the core of phase A). a1 1706 a2 1706 a3 ; 1706 on the B phase core b1 1706 b2 1706 b3 ; 1706 on the C-phase core c1 1706 c2 1706 c3Composed of three phases. Transmitter voltage (V) sA V sB and V sC The excitation is applied to the exciter unit 1702. The Sen transformer 1700 can transfer the excitation from the phase-separated... The exciter unit 1702 uses the sum of three available induced voltages from phases A, B, and C of one or more primary windings to achieve [the desired effect]. Figures 10A to 10E Trend operation points. Figure 17A , Figure 17C and Figure 17E The Sen transformers also include the LTC 1710 (LTC1, LTC2, and LTC3). When using the LTC, the effective number of turns in each compensated winding in each phase varies, and the magnitude and phase angle of the composite voltage are also variable.

[0127] According to an exemplary embodiment, the transmitting voltage of the Sen transformer 1700 can be V. s = 1 pu, the allowable amplitude (V) of the induced voltage (V) is 0.2 pu, and the voltage (x) across each tap of the LTC 1710 is 0.05 pu, existing with each secondary winding 1706 a1 1706 a2 1706 a3 1706 b1 1706 b2 1706 b3 1706 c1 1706 c2 and 1706 c3 There are N = 4 associated taps. Therefore, each tap in LTC2 and LTC3 is set to 0, 1, 2, 3, or 4; the corresponding secondary windings are activated at 0, 5, 10, 15, or 20%, contributing 0.0, 0.05, 0.10, 0.15, or 0.20 pu to the formation of the compensation voltage, respectively. However, each tap in LTC1 is set to 0, 1, 2, 3, or 4; the corresponding secondary windings are activated at 100, 105, 110, 115, or 120%, respectively, contributing 0.0, 0.05, 0.10, 0.15, or 0.20 pu to the formation of the compensation voltage. , and Contribute 1.00, 1.05, 1.10, 1.15, or 1.20 pu.

[0128] Composite voltage ( The active power (P) can be at any phase angle with the main line current (I). Therefore, the active power and reactive power (P) exchanged in parallel can be at any phase angle with the main line current (I). 2sh and Q 2sh The magnetic core enables bidirectional ground current flow. A compensation voltage at any phase angle to the main line current ( The exciter acts as an impedance regulator (IR). Note that the exciter exchanges active and reactive power (P0) with the line through its core. 1sh and Q 1sh And achieve bidirectional flow.

[0129] like Figures 17E to 17H As shown, the secondary winding (1706) a1 1706 b2 and 1706 c3 Each of the windings in the 1706 series is tapped with the same number of turns via LTC1; b1 1706 c2 and 1706 a3 Each of the windings is tapped with the same number of turns via LTC2; and the winding (1706) c1 1706 a2 and 1706 b3 Each of the LTC1, LTC2, and LTC3 is tapped with the same number of turns via LTC3. However, the number of turns for each set of secondary windings of LTC1, LTC2, and LTC3 can be different from each other.

[0130] like Figure 17B and Figure 17D As shown, by selecting the number of turns of each of the three windings of the three LTCs (LTC1, LTC2, and LTC3), and therefore the three The amplitude of the phase-shift induced voltage component, the compensation voltage in any phase ( ) can be obtained from the three-phase secondary winding set (1706 for compensation in phase A). a1 1706 b1 and 1706 c1 ; 1706 used for compensation in phase B a2 1706 b2 and 1706 c2 ; and 1706 for compensation in the C phase. a3 1706 b3 and 1706 c3 The sum of the phasors of the voltage induced in the π is obtained from the sum of the voltages induced in the π.

[0131] According to an exemplary embodiment, each of the taps in LTC1, LTC2, and LTC3 can be set to 0, 1, 2, 3, or 4. Each of the secondary windings associated with LTC2 and LTC3 can be activated at 0, 5, 10, 15, or 20%, respectively, contributing 0.0, 0.05, 0.10, 0.15, or 0.20 pu to the formation of the compensation voltage. Simultaneously, each of the secondary windings associated with LTC1 is activated at 100, 105, 110, 115, or 120%, respectively, contributing to the formation of the compensation voltage. , , Contribute 1.00, 1.05, 1.10, 1.15, or 1.20 pu.

[0132] based on Figure 8A With the exemplary winding configuration, the Sen transformer 1700 operates as follows:

[0133] •when and At this time, only LTC1 needs to be operated;

[0134] •when and At this time, only LTC2 and LTC3 need to be operated;

[0135] in , and It is the phase shift angle of the modified transmitting voltage relative to the transmitting voltage in phases A, B, and C.

[0136] like Figure 17E and Figure 11 As shown, when a phase shift angle of is selected... and At the operating point, the primary windings A, B, and C, and the secondary winding 1706 associated with LTC1 of the Sen transformer 1700. a1 1706 b2 and 1706 c3 The primary winding is in the active position (i.e., tap position 1, 2, 3, or 4); LTC2 and LTC3 are set to their minimum tap positions (i.e., tap position 0). A magnetomotive force (mmf) is generated in the primary winding and applied to the secondary winding associated with LTC1.

[0137] like Figure 17E and Figure 12 As shown, when a phase shift angle of is selected... , or or At the operating point, the primary windings A, B, and C, and the secondary winding 1706 associated with LTC1. a1 1706 b2 and 1706 c3 And the secondary winding 1706 associated with LTC3 c1 1706 a2 and 1706 b3 In active state; LTC2 is set to its minimum tap position. mmf is generated in the primary winding and applied to the secondary windings associated with LTC1 and LTC3.

[0138] like Figure 17E and Figure 13 As shown, when a phase shift angle of is selected... or or or At the operating point, the primary windings A, B, and C, and the secondary winding 1706 associated with LTC3. c1 1706 a2 and 1706 b3 In the active state; LTC1 and LTC2 are set to their minimum positions. mmf is generated in the primary winding and applied to the secondary winding associated with LTC3.

[0139] like Figure 17E and Figure 14 As shown, when a phase shift angle of is selected... and At the operating point, the primary windings A, B, and C, and the secondary winding 1706 associated with LTC3. c1 1706 a2 and 1706 b3 And the secondary winding 1706 associated with LTC2 b1 1706 c2 and 1706 a3 In active state; LTC1 is set to its minimum tap position. mmf is generated in the primary winding and applied to the secondary windings associated with LTC3 and LTC2.

[0140] like Figure 17E and Figure 15 As shown, when a phase shift angle of is selected... or or or At the operating point, the primary windings A, B, and C, and the secondary winding 1706 associated with LTC2. b1 1706 c2 and 1706 a3 In the active state; LTC1 and LTC3 are set to their minimum tap positions. mmf is generated in the primary winding and applied to the secondary winding associated with LTC2.

[0141] like Figure 17E and Figure 16 As shown, when a phase shift angle of is selected... or or or At the operating point, the primary windings A, B, and C, and the secondary winding 1706 associated with LTC2. b1 1706 c2 and 1706 a3And the secondary winding 1706 associated with LTC1 a1 1706 b2 and 1706 c3 In active state; LCT3 is set to its minimum tap position. mmf is generated in the primary winding and applied to the secondary windings associated with LTC2 and LTC1.

[0142] Figure 17I The Sen transformer 1700 is shown to be configured to have the same characteristics as... Figure 17A The modified transmitter voltage at the same operating point is shown. For example... Figure 17I As shown, all taps of the compensation voltage windings 1706a, 1706b, and 1706c of the compensation voltage unit 1704 are configured to operate closer to ground potential. This configuration can be used with... Figure 17A Compare the transformer configurations shown; when the taps of the compensation voltage windings 1706b and 1706c are configured as follows Figure 17A When operating closer to ground potential, as shown, the tap of the compensation voltage winding 1706a of the compensation voltage unit 1704 is also configured to operate closer to ground potential, instead of as... Figure 17A The diagram shows operation that is closer to line potential. Figure 17A and 17I All were set to In Figure 17B and Figure 17J The operation is performed at the same operation point shown in the corresponding phasor diagram. For example, regarding... Figure 17A The transformer discussed involves moving the contacts of the compensation voltage winding 1706a (LTC1) to a higher tap position in the direction towards the origin (e.g., (etc.) increased the compensation voltage in the winding 1706a of the compensation voltage unit 1704. However, Figure 17I The operation of the transformer differs because the contacts of the compensation voltage winding 1706a (LTC1) are moved away from the origin to a higher tap position (e.g., (etc.) increased the compensation voltage in the winding 1706a of the compensation voltage unit 1704. However, Figure 17A and 17I Both show the contacts of the compensation voltage windings 1706b and 1706c (LTC2 and LTC3) being moved to a higher tap position in the direction toward the origin (e.g., (etc.) The compensation voltage in windings b and c of the compensation voltage unit 1704 is increased. That is, in Figure 17A In this process, by moving the contacts at the tap positions of LTC1, LTC2, and LTC3 in the same direction toward the origin, the compensation voltage in each of the secondary windings is increased. For use with... Figure 17IThe same operating point of the transformer is achieved by increasing the compensation voltage by changing the tap movement direction of LTC1 to a higher tap position away from the origin, which is different from the corresponding direction of LTC2 and LTC3 moving towards a higher tap position from the origin.

[0143] Figure 17K and Figure 17M It shows Figure 17I The Sen transformer in such Figure 17L The three-phase arrangement is shown at any voltage operating point. Figures 17N to 17P The diagram shows the tap positions of on-load tap changers LTC1, LTC2, and LTC3 at any operating point of the Sen transformer 1700. For the compensation voltage unit 1704, this can be achieved by moving the contacts of LTC1 away from the origin to a higher tap position (e.g., ...). (etc.) to increase the secondary winding 1706 a1 1712 b2 1714 c3 The compensation voltage. For the secondary winding 1706 b1 1706 c1 1706 a2 1706 c2 1706 a3 and 1706 b3 This can be achieved by moving the contacts of LTC2 and LTC3 to a higher tap position in the direction towards the origin (e.g., (etc.) to increase the compensation voltage.

[0144] Figure 17Q and Figure 17R The modified transmitter voltage operating point and the corresponding active and reactive power flows (P0) according to exemplary embodiments of the present disclosure are shown. r and Q r The operating points, numbered 0 to 60, have an upper and lower limit of 10% of the permissible voltage.

[0145] Figure 17S Showing the target Figure 17I Each of the LTC1 taps in the transformer configuration is set to -1, 0, 1, 2, or 3; the corresponding secondary windings are activated at ratios of 95%, 100%, 105%, 110%, or 115%, respectively, to form a compensation voltage. , , Contribute 0.95, 1.00, 1.05, 1.10, or 1.15 pu. Figure 17T The operation points shown are Figure 17B or Figure 17J The operation points are the same.

[0146] Figure 17Uand Figure 17W It shows Figure 17S The Sen transformer in such Figure 17V The winding configuration in a three-phase arrangement at the voltage operating point is shown. Figures 17X to 17Z The diagram shows the tap positions of the on-load tap changers LTC1, LTC2, and LTC3 at any operating point of the Sen transformer 1700. The secondary winding in each phase is configured to generate... Figure 17I The modified transmitter voltage has already been discussed.

[0147] Figure 17AA and Figure 17AB The modified transmitter voltage operating point set and the corresponding active and reactive power flows (P) in the power flow enhancement region according to exemplary embodiments of the present disclosure are shown. r and Q r Operation point. For example... Figure 17AA and Figure 17AB As shown, the area of ​​increased tidal current can be approximately to It operates within the range of relative phase angles.

[0148] Figure 17AC and Figure 17AE This shows the Sen transformer in such a way Figure 17AD The three-phase arrangement at the voltage operating point shown requires only six compensated secondary windings. Based on the winding configuration of the compensated voltage unit 1704, the phase angle range also corresponds to the power flow increase region. This is because the Sen transformer 1700 is configured to operate at, for example... Figure 17AA and Figure 17AB As shown, it operates within a limited phase angle range, so the compensation voltage unit 1704 can be modified by removing the secondary winding associated with a phase outside the range of interest or by putting it inactive. For example, for... Figure 17AC The compensation voltage unit 1704, secondary winding 1706 b1 1706 c2 1706 a3 It is in an inactive state, or can be omitted or removed from the transformer configuration. The inactive secondary winding is grouped with LTC2. Figures 17AF to 17AG The diagram shows the tap positions of on-load tap changers LTC1 and LTC3 at any operating point of the Sen transformer 1700. Operation requires only two tap changers because a secondary winding corresponding to a phase outside the finite phase angle range of interest is inactive during operation, or is omitted or removed from the transformer configuration as previously described.

[0149] Figure 17AH and Figure 17AIThe modified transmitter voltage operating point set and the corresponding active and reactive power flows (P) in the power flow reduction region according to exemplary embodiments of the present disclosure are shown. r and Q r Operation point. For example... Figure 17AH and Figure 17AI As shown, the region where the power flow decreases can be approximately to It operates within the range of relative phase angles.

[0150] Figure 17AJ and Figure 17AL This shows the Sen transformer in such a way Figure 17AK The three-phase arrangement at the voltage operating point shown requires only six compensated secondary windings. Based on the winding configuration of the compensated voltage unit 1704, the phase angle range also corresponds to the power flow reduction region. This is because the Sen transformer 1700 is configured to operate at, for example... Figure 17AH and 17AI As shown, it operates within a limited phase angle range, so the compensation voltage unit 1704 can be modified by removing the secondary winding associated with a phase outside the phase angle range of interest or by putting it in an inactive state. For example, for Figure 17AJ The compensation voltage unit 1704, secondary winding 1706 c1 1706 a2 1706 b3 It is in an inactive state, or can be omitted or removed from the transformer configuration. The inactive secondary winding is grouped with LTC3. Figures 17AM to 17AN The diagram shows the tap positions of on-load tap switches LTC1 and LTC2 at any operating point of the Sen transformer 1700. Operation requires only two tap switches because a secondary winding corresponding to a phase outside the finite phase angle range of interest is inactive during operation, or is omitted or removed from the transformer configuration as previously described.

[0151] Controlling the power flow in a line using a power flow controller with a parallel-series or parallel-parallel configuration has a side effect: adjacent lines need to adjust their power flow to maintain the overall power flow from power source to load. However, power from one line can be precisely transferred to another line via a series-series configuration without altering the power flow in any other lines.

[0152] Figure 18A A single-line diagram of a Sen transformer with a series-to-series configuration according to an exemplary embodiment of the present disclosure is shown. Figure 18AAs shown, the Sen transformer 1800 includes an exciter unit 1802 and two compensation voltage units 1804A and 1804B connected in series with the exciter unit 1802. Each compensation voltage in the "dominant" line can have any amplitude within its permissible limits and any phase angle relative to the line voltage and the mainstream line current, allowing independent control of active and reactive power flow in that line as needed. Furthermore, each series-compensated voltage in the "follower" line has a specific amplitude and phase angle relative to the main line current, allowing active and reactive power from the "dominant" line to be bidirectionally transferred to the "follower" line. This technique provides the desired power flow management for multi-line transmission systems by reducing power flow in overloaded lines and increasing power flow in underloaded lines with minimal impact on other uncompensated lines.

[0153] Figure 18B A Sen transformer 1800 with a series-to-series connection between the exciter unit 1802 and the compensation voltage units 1804A and 1804B is shown. Figure 18B As shown, the line voltage (V) s The Y-connected primary windings 1808A, 1808B, and 1808C of the three-phase transformer connected in parallel are applied to the exciter unit 1802. In the compensation voltage unit 1804A, there are a total of nine secondary windings (1806 on the core of phase A). a11 1806 a12 and 1806 a13 ; 1806 on the B phase core b11 1806 b12 1806 b13 ; 1806 on the C-phase core c11 1806 c12 1806 c13 The three-phase compensation voltage can be obtained, where each phase is a three-winding set (for the compensation voltage of phase A, 1806). a11 1806 b11 and 1806 c11 ; Regarding the compensation voltage in phase B, 1806 a12 1806 b12 and 1806 c12 ; and 1806 for the compensation voltage in phase C. a13 1806 b13 and 1806 c13 The sum of the phasors of the voltages induced in the windings. This is achieved by selecting the number of turns in each of the three windings via the corresponding LTC control for each group (LTC1, LTC2, and LTC3), and thus the three... The amplitude of the phase-shift induced voltage component can be selected based on the composite compensation voltage amplitude and the relative phase angle with respect to the line voltage. In the compensation voltage unit 1804B, there are nine secondary windings (1806 on the core of phase A). a21 1806 a22 and 1806 a23 ; 1806 on the B phase core b21 1806 b22 1806 b23 ; and the 1806 on the C-phase core. c21 1806 c22 1806 c23 The three-phase compensation voltage can be obtained, where each phase is a three-winding set (for the compensation voltage of phase A, 1806). a21 1806 b21 and 1806 c21 ; Regarding the compensation voltage in phase B, 1806 a22 1806 b22 and 1806 c22 ; and 1806 for the compensation voltage in phase C. a23 1806 b23 and 1806 c23 The sum of the phasors of the voltages induced in the windings. This is achieved by selecting the number of turns in each of the three windings via the corresponding LTC control for each group (LTC1, LTC2, and LTC3), and thus the three... The amplitude of the phase-shift induced voltage component can be selected by combining the composite compensation voltage amplitude and the relative phase angle with respect to the line voltage.

[0154] Figure 19 A general-purpose Sen transformer (GST) according to an exemplary embodiment of this disclosure is shown, which is configured to generate parallel-compensated voltage and series-compensated voltage in a single unit. Figure 19 As shown, the GST 1900 includes an exciter unit 1902 and a compensation voltage unit 1904. The compensation voltage unit 1904 includes multiple parallel compensator units 1906. m and multiple series compensator units 1908 n Each parallel-compensator unit 1906 m And series-compensator unit 1908 n They are connected to the corresponding power lines respectively. Series-compensator unit 1908 n Configured to independently control the active and reactive power flow in each line, and to transfer active and reactive power from one or more “dominant” lines to one or more “follower” lines. Parallel-Compensator Unit 1906 mConfigured to connect isolated networks with different voltages and phase angles to independently control active and reactive power flow in each line, and to transfer active and reactive power from one or more “dominant” lines to one or more “follower” lines. Series compensator unit 1908 n Parallel-compensator unit 1906 m Each of these is induced from the exciter voltage through the action of a transformer. Therefore, any mismatch in active and reactive power between the various compensation voltages will flow to the lines supplying power to the exciter unit 1902 of the GST 1900.

[0155] Control 1910 and / or control operations for switching the LTC based on the desired operating point can be performed by a computing device. According to an exemplary embodiment, the computing device may include one or more processing devices, such as a microprocessor, central processing unit, microcomputer, programmable logic unit, or any other suitable hardware processing device required. The computing device may be configured with computer program code for performing the specific functions described herein. The program code may be stored on a computer-usable medium, which may refer to memory (such as a memory device of the computing device), which may be memory semiconductor (e.g., DRAM, etc.). These computer program products may be tangible, non-transitory means for providing software to various hardware components of the respective device as needed to perform tasks associated with the exemplary embodiments described herein. The computer program (e.g., computer control logic) or software may be stored in the memory device. According to an exemplary embodiment, the computer program may also be received and / or remotely accessed via other components of the computing device (such as a receiver or receiving device). When such a computer program is executed, it may cause a processor to implement the methods and exemplary embodiments discussed herein and may represent a controller of the processor. When implementing this disclosure using software, the software may be stored in a non-transitory computer-readable medium and, where applicable, loaded into the computing device using a removable storage drive, interface, hard disk drive, or communication interface, etc.

[0156] One or more processors of a computing device may include one or more modules or engines configured to perform the functions of the exemplary embodiments described herein. Each of the modules or engines may be implemented using hardware, and in some cases, may also utilize software, such as program code and / or programs stored in memory. In this case, the program code may be compiled by the corresponding processor (e.g., by a compilation module or engine) prior to execution. For example, the program code may be source code written in a programming language that is translated into a low-level language (such as assembly language or machine code) for execution by one or more processors and / or any other hardware component. The compilation process may include the use of lexical analysis, preprocessing, parsing, semantic analysis, syntax-guided translation, code generation, code optimization, and any other techniques that may be suitable for translating the program code into a low-level language suitable for controlling the computing device to perform the functions disclosed herein. Such a process will result in the computing device being specifically configured and uniquely programmed to perform the functions described above, which will be apparent to those skilled in the art.

[0157] Figure 20 A method for generating a compensation voltage according to an exemplary embodiment of the present disclosure is shown. This method can be achieved through methods such as... Figure 8A , 17C This is achieved using transformers configured as shown in Figures 17K, 17U, 17AC, 17AJ, 18B, or 19. As shown in the figures above, the transformer has an exciter unit and a compensation voltage unit. The exciter unit comprises a three-phase transformer with parallel Y-connected primary windings. The compensation voltage unit comprises a plurality of series-connected secondary windings, each secondary winding comprising one secondary winding from each phase of the exciter unit. The compensation voltage unit also includes a plurality of on-load tap changers. Each on-load tap changer is associated with a set of secondary windings, each set comprising one secondary winding from each phase of the exciter unit. According to an exemplary embodiment, each secondary winding is assigned to a set of secondary windings, wherein each secondary winding is positioned (i.e., located) at the same distance from the associated primary winding of the exciter unit. According to yet another exemplary embodiment, all secondary windings in the compensation voltage unit, and the sub-windings between two consecutive taps, have substantially similar heights to the primary windings in the exciter unit. The sub-windings may or may not be interleaved. When this method is executed, the controller is configured to select the operating point of the transformer (step 2000). The operating point can be selected based on input received by the controller (e.g., 1910) from an operator or user. Figures 10A to 10EVarious operating points for generating compensation voltages based on one or more parameters of the transformer are illustrated. According to another exemplary embodiment, the input can be automatically generated by an external computing system configured to monitor the operation of the power system and automatically select the operating point based on the required power flow control. Based on the selected operating point, a controller (e.g., 1910) selects an on-load tap position for each of the group of secondary windings associated with each on-load tap changer (step 2010). The transformer's compensation-voltage unit generates the compensation voltage by summing the effective voltages induced in the secondary winding group for each on-load tap changer (step 2020). Figures 11 to 16 The resulting compensation voltage generated by the secondary winding of the compensation voltage unit for the corresponding operating point is shown. This operation can be repeated as one or more power lines, the power grid, and / or the required compensation voltage change.

[0158] Those skilled in the art will understand that the invention may be embodied in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments disclosed herein are to be considered illustrative in all respects and not restrictive. The scope of the invention is indicated by the appended claims rather than the foregoing description, and all variations within their meaning, scope, and equivalence are intended to be included therein.

Claims

1. A transformer for generating a compensation voltage, the transformer comprising: Exciter unit; as well as Compensation voltage unit The exciter unit includes a three-phase transformer with a parallel Y-connected primary winding or three single-phase transformers. The compensation voltage unit includes: Multiple secondary windings connected in series, including one secondary winding from each phase of the exciter unit; as well as Multiple on-load tap changers, each associated with a secondary winding group comprising one secondary winding from each phase of the exciter unit, wherein each secondary winding in the secondary winding group is located at the same distance from the associated primary winding of the exciter unit, wherein all windings have similar heights, and wherein each on-load tap changer is configured to change the effective number of turns of the associated secondary winding group by connecting to one of the multiple taps associated with each secondary winding according to a selected operating point.

2. The transformer according to claim 1, comprising: A parallel-series configuration in which the exciter unit and the compensation voltage unit are electrically connected.

3. The transformer according to claim 1, comprising: Parallel-parallel configuration, wherein the exciter unit and the compensation voltage unit are electrically isolated.

4. The transformer according to claim 1, comprising: A series-to-series configuration, wherein the exciter unit is connected to a transmission line and a plurality of compensation voltage units, wherein each compensation voltage unit is electrically connected to one of the plurality of transmission lines.

5. The transformer according to claim 1, wherein, The compensation voltage is the sum of the effective voltages induced in the multiple secondary windings for each phase in the compensation voltage unit.

6. The transformer of claim 1, wherein the plurality of taps associated with each secondary winding are separated by an interval of x%.

7. The transformer according to claim 6, wherein x is an integer value, such that .

8. The transformer according to claim 5, wherein, Based on five taps numbered 0, 1, 2, 3, and 4, each tap spaced 5% apart, the effective voltage variation in each secondary winding is as follows: the amplitude of the series compensation voltage varies from 0 to 20% of the primary voltage, and the relative phase angle is... arrive The amplitude of the parallel compensation voltage varies between 80% and 120% of the primary voltage, and the phase shift angle varies between [the values ​​of the two voltages]. arrive The changes between them.

9. The transformer of claim 1, wherein the on-load tap changer is configured as a single-phase on-load tap changer, and three single-phase on-load tap changers are connected to the same number of turns of the secondary winding group.

10. The transformer of claim 1, wherein the on-load tap changer is configured as a plurality of three-phase on-load tap changers, wherein each on-load tap changer is connected to the same number of turns of the secondary winding group.

11. The transformer according to claim 1, wherein the compensation unit further comprises: For each phase, the third winding is delta connected, and only one terminal comes out of the transformer for grounding purposes.

12. The transformer of claim 11, wherein each third winding is the innermost winding immediately adjacent to the transformer core.

13. The transformer of claim 11, wherein the third winding is configured to allow the circulation of zero-sequence current.

14. A method for generating a compensation voltage using a transformer having an exciter unit and a compensation voltage unit, comprising a three-phase transformer or three single-phase transformers having parallel Y-connected primary windings, wherein the compensation voltage unit comprises: Multiple secondary windings connected in series, the secondary windings including one secondary winding from each phase of the exciter unit; and multiple on-load tap changers, wherein each on-load tap changer is associated with a secondary winding group, the secondary winding group comprising one secondary winding from each phase of the exciter unit, wherein each secondary winding in the secondary winding group is located at the same distance from the associated primary winding of the exciter unit, and wherein all windings have similar heights, the method comprising: Select the operating point of the transformer; Based on the operating point, an on-load tap position is selected for each secondary winding in the secondary winding group associated with each on-load tap changer; and The compensation voltage is generated by summing the effective voltages induced in the secondary winding groups for each on-load tap changer.

15. The method according to claim 14, wherein, Based on the selected on-load tap position, each three-phase on-load tap changer alters the amplitude of the series compensation voltage and the relative phase angle of the series compensation voltage.

16. The method of claim 15, wherein each secondary winding has a total of five taps spaced at 5% intervals, the method further comprising: The amplitude of the series compensation voltage is changed from 0% to 20% of the primary voltage.

17. The method of claim 15, further comprising: exist and The relative phase angle of the series compensation voltage is changed between them.

18. The method of claim 15, further comprising: exist and The relative phase angle between the series compensation voltages is changed. as well as Using an additional switch on the transformer, the voltage applied to the secondary winding is reversed to... The relative phase angle doubles the maximum active power flow.

19. The method of claim 17, wherein each on-load tap changer includes on-load tap positions 0, 1, 2, 3, and 4, the method comprising: Select one with a relative phase angle of Operation points; Set a first on-load tap changer to connect on-load tap position 1, 2, 3 or 4 on each secondary winding; A second on-load tap changer is provided to connect the on-load tap position 0 on each secondary winding; as well as A third on-load tap changer is provided to connect the on-load tap position 0 on each secondary winding.

20. The method of claim 17, wherein each on-load tap changer includes on-load tap positions 0, 1, 2, 3, and 4, the method comprising: Select one with a relative phase angle of Operation points; Set a first on-load tap changer to connect on-load tap position 1, 2, 3 or 4 on each secondary winding; A second on-load tap changer is configured to connect the on-load tap position 0 on each secondary winding; and A third on-load tap changer is provided to connect on-load tap position 1, 2, 3 or 4 on each secondary winding.

21. The method of claim 17, wherein each on-load tap changer includes on-load tap positions 0, 1, 2, 3, and 4, the method comprising: Select one with a relative phase angle of Operation points; Set the first on-load tap changer to the on-load tap position 0 connected on each secondary winding; A second on-load tap changer is provided to connect the on-load tap position 0 on each secondary winding; as well as A third on-load tap changer is provided to connect on-load tap position 1, 2, 3 or 4 on each secondary winding.

22. The method of claim 17, wherein each on-load tap changer includes on-load tap positions 0, 1, 2, 3, and 4, the method comprising: Select one with a relative phase angle of Operation points; Set the first on-load tap changer to the on-load tap position 0 on each secondary winding; A second on-load tap changer is provided to connect on-load tap position 1, 2, 3 or 4 on each secondary winding; as well as A third on-load tap changer is provided to connect on-load tap position 1, 2, 3 or 4 on each secondary winding.

23. The method of claim 17, wherein each on-load tap changer includes on-load tap positions 0, 1, 2, 3, and 4, the method comprising: Select one with a relative phase angle of Operation points; Set the first on-load tap changer to connect the on-load tap position 0 on each secondary winding; A second on-load tap changer is provided to connect on-load tap position 1, 2, 3 or 4 on each secondary winding; as well as A third on-load tap changer is provided to connect the on-load tap position 0 on each secondary winding.

24. The method of claim 17, wherein each on-load tap changer includes on-load tap positions 0, 1, 2, 3, and 4, the method comprising: Select one with a relative phase angle of Operation points; Set a first on-load tap changer to connect on-load tap position 1, 2, 3 or 4 on each secondary winding; A second on-load tap changer is provided to connect on-load tap position 1, 2, 3 or 4 on each secondary winding; as well as A third on-load tap changer is provided to connect the on-load tap position 0 on each secondary winding.

25. The method according to claim 14, wherein, Based on the selected on-load tap position, each three-phase on-load tap changer alters the amplitude of the parallel compensation voltage and the phase shift angle of the parallel compensation voltage.

26. The method of claim 24, wherein each secondary winding has a total of five taps spaced at 5% intervals, the method further comprising: The amplitude of the parallel compensation voltage is changed from 80% to 120% of the primary voltage.

27. The method of claim 24, further comprising: exist arrive The phase shift angle of the parallel compensation voltage is changed between these parameters.

28. The method of claim 26, wherein each on-load tap changer includes on-load tap positions 0, 1, 2, 3, and 4, the method comprising: Select one with a phase shift angle of Operation points; Set a first on-load tap changer to connect on-load tap position 1, 2, 3 or 4 on each secondary winding; A second on-load tap changer is provided to connect the on-load tap position 0 on each secondary winding; as well as A third on-load tap changer is provided to connect the on-load tap position 0 on each secondary winding.

29. The method of claim 26, wherein each on-load tap changer includes on-load tap positions 0, 1, 2, 3, and 4, the method comprising: Select one with a phase shift angle of or , or Operation points; Set a first on-load tap changer to connect on-load tap position 1, 2, 3 or 4 on each secondary winding; A second on-load tap changer is configured to connect the on-load tap position 0 on each secondary winding; and A third on-load tap changer is provided to connect on-load tap position 1, 2, 3 or 4 on each secondary winding.

30. The method of claim 26, wherein each on-load tap changer includes on-load tap positions 0, 1, 2, 3, and 4, the method comprising: Select one with a phase shift angle of or or or Operation points; Set the first on-load tap changer to the on-load tap position 0 connected on each secondary winding; A second on-load tap changer is provided to connect the on-load tap position 0 on each secondary winding; as well as A third on-load tap changer is provided to connect on-load tap position 1, 2, 3 or 4 on each secondary winding.

31. The method of claim 26, wherein each on-load tap changer includes on-load tap positions 0, 1, 2, 3, and 4, the method comprising: Select one with a phase shift angle of Operation points; Set the first on-load tap changer to connect the on-load tap position 0 on each secondary winding; A second on-load tap changer is provided to connect on-load tap position 1, 2, 3 or 4 on each secondary winding; as well as A third on-load tap changer is provided to connect on-load tap position 1, 2, 3 or 4 on each secondary winding.

32. The method of claim 26, wherein each on-load tap changer includes on-load tap positions 0, 1, 2, 3, and 4, the method comprising: Select one with a phase shift angle of or or or Operation points; Set the first on-load tap changer to connect the on-load tap position 0 on each secondary winding; A second on-load tap changer is provided to connect on-load tap position 1, 2, 3 or 4 on each secondary winding; as well as A third on-load tap changer is provided to connect the on-load tap position 0 on each secondary winding.

33. The method of claim 26, wherein each on-load tap changer includes on-load tap positions 0, 1, 2, 3, and 4, the method comprising: Select one with a phase shift angle of or or- or The operation point; Set a first on-load tap changer to connect on-load tap position 1, 2, 3 or 4 on each secondary winding; A second on-load tap changer is provided to connect on-load tap position 1, 2, 3 or 4 on each secondary winding; as well as A third on-load tap changer is provided to connect the on-load tap position 0 on each secondary winding.

34. The method of claim 24, further comprising: For the most cost-effective configuration of the transformer, when all taps of the compensation voltage unit are closer to ground potential, arrive The phase shift angle of the parallel compensation voltage is changed between them.

35. The method of claim 24, further comprising: exist The phase shift angle of the parallel compensation voltage is changed between 0 and 0.

36. The method of claim 24, further comprising: From 0 The phase shift angle of the parallel compensation voltage is changed between them.

Images