Voltage reactive comprehensive regulator topology circuit based on equivalent electrical distance regulation principle

Abstract

The invention discloses a voltage reactive power comprehensive regulator topology circuit based on an equivalent electrical distance regulation principle, belongs to the technical field of power distribution network and distributed power supply grid connection, and is used for solving the problems that long feeder line voltage exceeds a lower limit, tail end voltage exceeds an upper limit due to distributed photovoltaic access, and line loss is caused. The device mainly comprises a closed iron core magnetic circuit, a primary parallel excitation winding, a secondary series voltage regulating winding and a secondary parallel reactive compensation winding, wherein the multi-tap secondary coil is connected with the on-load voltage regulation tap switch to form a secondary series voltage regulation winding; the capacitor, the current-limiting reactor and the capacitor fling-cut switch are connected to form a secondary parallel reactive compensation winding; in specific application, the primary winding is connected to a power supply and distribution line in parallel, the secondary series voltage regulating winding is connected between the power supply and distribution line and a regulated object in series, and the secondary parallel reactive compensation winding is connected to the line in parallel through the primary winding.

Description

Technical Field

[0001] The present invention belongs to the technical field of power distribution network and distributed power grid connection, and particularly relates to the problem of terminal voltage exceeding upper and lower limits and line reactive power loss control caused by long feeder or distributed photovoltaic access. Background Art

[0002] The large-scale access of distributed renewable energy, flexible loads, etc. has put forward higher requirements on the distribution network. However, on the one hand, the traditional distribution network has a relatively weak foundation, and there are problems such as long power supply radius, small conductor cross-section, and heavy load at the end of the line. Some substations are affected by low voltage for a long time; on the other hand, the construction of medium and low voltage distribution networks lags behind the growth of electricity load, the layout and structure of the distribution network are unreasonable, the power supply equipment is outdated, and the line loss is increased; in addition, most new energy plants and stations are connected to the end of the line in remote areas, rural mountainous areas, etc. due to resource and geographical location issues, which has a serious impact on the power system's power flow changes, transformers, power balance, etc., and aggravates the problems of voltage over-limit and network transmission loss.

[0003] Effective measures to solve the voltage quality problem of distribution network include: increasing the cross-section of conductors, voltage regulators, parallel capacitors, series capacitors, using distributed power sources, using power electronic equipment, using energy storage equipment, etc.; the current research directions and solutions for low voltage management at home and abroad are basically: building new substations, on-load voltage regulation of main transformers, optimizing the gears of distribution transformers, changing line parameters (such as increasing wire diameter), changing the reactive power of the line, using 10kV line automatic voltage regulators, etc.

[0004] However, the existing voltage regulation methods all have certain shortcomings. The methods of thickening the wires and creating new circuits or building new substations have the disadvantages of large investment, long construction period and long investment recovery period; the method of using traditional on-load voltage regulating transformers has the defects of large equipment capacity, single regulation means and large inherent losses; the method of using power electronic devices or energy storage devices to regulate the voltage has the disadvantages of high equipment cost, weak ability to withstand electrical stress and difficult operation and maintenance; the solution using reactive power compensation devices cannot meet the voltage regulation requirements at the end of long-distance power supply lines. When there are many busbar outgoing lines from the substation, the load curves and voltage drops of each outgoing line are different, and it cannot be guaranteed that the voltage of all lines meets the requirements. Therefore, this voltage regulation method has poor flexibility and pertinence. When the feeder is complex, it often causes the voltage to be higher near the substation and lower far from the substation.

[0005] The patent of this invention proposes a new topology of a long feeder voltage / reactive power comprehensive management device based on the principle of equivalent electrical distance regulation. It adopts the new technology of electromagnetic coupling series voltage regulation and parallel reactive power compensation. Compared with conventional voltage regulators and parallel compensation devices, it has both series compensation and parallel compensation to reduce the active current and reactive current of the line. It has the characteristics of simple control method and flexible and changeable usage scenarios. It can stabilize the long feeder voltage at a qualified level and dynamically compensate for the reactive loss of the line and transformer, thereby solving the problems of large energy loss, low power quality and reliable power supply in the substation. Summary of the invention

[0006] The invention mainly provides a voltage and reactive power integrated regulator topology circuit based on the principle of equivalent electrical distance regulation. The voltage and reactive power integrated regulator belongs to a three-winding topology structure, including a closed iron core magnetic circuit, a parallel primary excitation winding, a secondary series voltage regulating winding, a secondary parallel reactive power compensation winding, a multi-tap secondary coil, an on-load voltage regulating tap changer, a capacitor switching switch, a current limiting reactor, a capacitor, a casing, accessories, etc.; its characteristics are: in the series voltage regulating and parallel reactive power compensation windings, the closed iron core magnetic circuit realizes the voltage conversion and power conversion between the primary winding and the secondary coil; in the secondary series voltage regulating winding, the voltage phasor between the taps of the secondary coil is established, and then the secondary winding voltage is adjusted by the on-load tap changer; in the secondary parallel reactive power compensation winding, the principle that the current direction of the parallel capacitor and the line inductive reactive power is 180° different is used to connect a capacitor of appropriate capacity to achieve reactive power balance, and the discrete adjustment of the reactive power of the connected line is achieved by the on-off state of the switching switch of the capacitor branch.

[0007] The primary winding of the voltage and reactive power integrated regulator provided by the patent of the present invention is connected in parallel to the power supply and distribution line, and the secondary series voltage regulating winding is connected in series to the power supply and distribution line. The secondary series voltage regulating winding is composed of a multi-tap secondary coil connected to an on-load voltage regulating tap changer. It is connected in series to the power supply and distribution line, and the voltage conversion and power conversion between the primary winding and the secondary regulating winding are realized through a closed iron core magnetic circuit. The increase and decrease of the series voltage at the line access point are adjusted by selecting the on-load tap changer; the secondary parallel reactive compensation winding is connected to the line in parallel through the primary winding, and the secondary parallel reactive compensation winding and the current limiting reactor form a branch. The branch capacitance is affected by the switch state. The voltage and power conversion are realized between the primary winding and the secondary parallel reactive compensation winding through the closed iron core magnetic circuit. The main purpose of the current limiting reactor is to reduce the influence of harmonics, improve system stability and limit the influence of charging current of the capacitor group. At this time, the reactive power consumed by the secondary parallel reactive compensation winding is exchanged through the primary winding and the line.

[0008] The secondary series voltage regulating winding of the voltage and reactive power integrated regulator provided by the patent of the present invention is connected to the power supply and distribution line, wherein: the three-phase winding on the primary side can be connected into a transformer connection group suitable for various requirements, connected in parallel to the live wire of the three-phase power supply and distribution line, and the three-phase secondary regulating winding is directly connected in series to the power supply and distribution line; the secondary parallel reactive power compensation winding is connected to the line after being connected to the primary winding in parallel, wherein: under the premise that the number of turns of the primary winding and the secondary winding remains unchanged, the size of the capacitor C in the parallel reactive power compensation module can be affected by controlling the switch state, affecting the reactive power injected into the line by the secondary parallel winding, and dynamic reactive power compensation is achieved by changing the switch state.

[0009] The three-phase winding on the primary side of the voltage and reactive power integrated regulator provided by the patent of the present invention can be connected into a transformer connection group suitable for various requirements, connected in parallel to the live wire of the three-phase power supply and distribution line, and the three-phase secondary regulating winding is directly connected in series in the power supply and distribution line; it can also be combined with an on-load tap changer and a polarity switch to achieve graded voltage regulation by the on-load voltage regulating tap changer, and positive and negative bidirectional control by the polarity switch, so as to achieve high and low voltage regulation of single-phase or three-phase at the end of the line.

[0010] The secondary series voltage regulating winding of the voltage and reactive power integrated regulator provided by the patent of the present invention has a specific number of taps of its on-load tap changer that can be arbitrarily configured according to actual needs. If the regulation accuracy requirement is high, the number of taps can be increased. If the regulation accuracy requirement is not high, the number of taps can be reduced to control the overall volume, weight and cost of the device; the secondary parallel reactive power compensation winding branch capacitance capacity configuration and the number of switches can be arbitrarily configured according to actual needs. If the regulation accuracy requirement is high, the number of switches and capacitor groups can be increased. If the regulation accuracy requirement is not high, the number of switches and capacitor groups can be reduced to control the overall volume, weight and cost of the device. At the same time, its wiring can be Y-connected or Δ-connected according to actual conditions.

[0011] The parallel primary excitation winding and the secondary series voltage regulating winding are mainly used to control the voltage below the access point, and the voltage and current conversion and electric energy transmission are realized based on the principle of electromagnetic induction. The graded regulation of the series-in line voltage is realized through the on-load voltage regulating tap changer, so as to realize the voltage increase and decrease regulation of the single-phase or three-phase below the access point, or the on-load tap changer is combined with the polarity switch, and the graded voltage regulation is realized by the on-load voltage regulating tap changer, and the positive and negative bidirectional control is realized by the polarity switch, so as to realize the high and low voltage regulation of the single-phase or three-phase at the end of the line, solve the problem of terminal voltage exceeding the limit caused by the high penetration rate and long feeder access of distributed power sources, so as to ensure the consumption of high-penetration distributed power sources by the distribution network. Compared with the existing on-load voltage regulating transformer, in order to achieve the same voltage regulation effect, the capacity of the voltage and reactive power integrated regulator provided by the present invention only needs to be 10% to 20% of the capacity of the single-phase or three-phase on-load voltage regulating transformer.

[0012] The parallel primary excitation winding and the secondary parallel reactive compensation winding are mainly used to control the reactive power of the access point. The principle that the current direction of the parallel capacitor and the line inductive reactive power is 180° different is used to connect a capacitor of appropriate capacity to achieve reactive power balance. The reactive module of the voltage and reactive integrated regulator can adopt mechanical switch switching or thyristor switching according to different application scenarios (different control methods can achieve voltage / reactive power control, the difference lies in the adjustment time, reliability and economy). This patent takes the mechanical switch switching method to control the parallel reactive compensation unit as an example, but it also protects other forms of switch switching schemes to achieve the purpose of supplementing the system reactive power, increasing the voltage at the end of the distribution network, and reducing the system network loss.

[0013] The innovative thinking of the technical solution and the beneficial effects of the present invention are:

[0014] The present invention provides a voltage and reactive power integrated regulator topology circuit based on the equivalent electrical distance regulation principle, which can independently control the series voltage regulation module and the parallel reactive power module, or integrate and coordinate the two, and can simultaneously regulate the voltage and reactive power below the device access node on a 10kV line.

[0015] The present invention provides a voltage and reactive power integrated regulator topology circuit based on the equivalent electrical distance regulation principle. Compared with the existing cascade type on-load voltage regulating transformer voltage regulating topology circuit, the capacity of the voltage and reactive power integrated regulator provided by the present invention only needs to be 10% to 20% of the capacity of the cascade type on-load voltage regulating transformer or auto-coupling voltage regulator.

[0016] The present invention provides a voltage and reactive power integrated regulator topology circuit based on the equivalent electrical distance regulation principle. Compared with the voltage regulation topology circuit of pure power electronic technology, the series voltage regulation module of the voltage regulation module has large thermal capacity, strong impact resistance, good durability, high reliability and better economic cost.

[0017] The present invention provides a voltage and reactive power integrated regulator topology circuit based on the equivalent electrical distance regulation principle, wherein the series voltage regulating module thereof can realize bidirectional regulation of the voltage below the access point without the need for a polarity switch, and has the advantage of simple control.

[0018] The present invention provides a voltage-reactive integrated regulator topology circuit based on the equivalent electrical distance regulation principle. Its parallel reactive compensation module provides two control switch schemes. The capacitor switching switch switching control method has the advantages of simple structure, convenient control, stable performance and low cost; the thyristor switching control method has the advantages of long life, high speed, no mechanical wear and smooth switching, and can be selected according to actual needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1A schematic diagram of an electrical system application of a preferred embodiment of a single-phase voltage and reactive power integrated regulator provided by the present invention; Figure 2 A schematic diagram of an electrical system application of a preferred embodiment of a three-phase voltage and reactive power integrated regulator provided by the present invention; Figure 3 A schematic diagram of the electrical principle of a preferred embodiment of a three-phase voltage-reactive integrated regulator provided by the present invention, wherein the primary excitation winding is connected in parallel with the secondary series voltage regulating winding; Figure 4 A schematic diagram of the electrical principle of a preferred embodiment of a three-phase voltage-reactive integrated regulator with a parallel primary excitation winding and a parallel secondary reactive compensation winding provided by the present invention; Figure 5 A schematic diagram of the electrical principle of a preferred embodiment of a single-phase voltage and reactive power integrated regulator topology circuit provided by the present invention; Figure 6 A schematic diagram of electrical wiring of a single-phase voltage and reactive power integrated regulator topology provided by the present invention; Figure 7 A schematic diagram of the electrical principle of a three-phase voltage and reactive power integrated regulator topology provided by the present invention; Figure 8 The present invention provides a schematic diagram of electrical wiring of a preferred embodiment of a three-phase voltage and reactive power integrated regulator topology circuit.

[0020] Attached Figure 1 The symbols of the components are as follows: It is the equivalent power supply of the power distribution system; The power supply voltage of each phase when single-phase power supply; is the supply voltage of single-phase power users; R2+X2 is the impedance of the single-phase power supply line; T2 is the step-down transformer at the substation end and the step-down transformer in the distribution area or the distributed generation grid-connected transformer; S T2 is the transformer capacity; S R is the capacity of the single-phase voltage and reactive power integrated regulator; A1 and A2 are the inlet and outlet terminals of the voltage and reactive power integrated regulator; P DG and Q DG is the power generated by the distributed power source, generally Q DG =0;P L and Q L is the active and reactive power of the load; N is the neutral point or neutral line.

[0021] Attached Figure 2 The symbols of the components are as follows: It is the equivalent power supply of the power distribution system; is the voltage at the head end of the distribution line; The voltage at the grid connection point of the voltage and reactive power integrated regulator; is the voltage at the end of the distribution line; R+X is the impedance of the power supply line; T1 is the step-down transformer at the substation end and the step-down transformer in the distribution area or the distributed generation grid-connected transformer; S T1 is the transformer capacity; S RIt is the capacity of single-phase voltage and reactive power integrated regulator.

[0022] Attached Figure 3 , Attachment Figure 4 , Attachment Figure 5 The symbols of the components are as follows: A1 is the live wire terminal of the single-phase voltage and reactive integrated regulator connected to the power supply side line; A2 is the live wire terminal of the single-phase voltage and reactive integrated regulator connected to the load side line; A is the head end of the parallel energy-taking winding of the single-phase voltage and reactive integrated regulator; X is the end of the parallel energy-taking winding of the single-phase voltage and reactive integrated regulator; 11 is the series voltage regulating winding of the single-phase voltage and reactive integrated regulator; 12 is the excitation parallel winding of the single-phase voltage and reactive integrated regulator; 13 is the parallel primary excitation winding and secondary series winding of the single-phase voltage and reactive integrated regulator The voltage regulating winding core; 14 is the current limiting reactor of the single-phase voltage and reactive integrated regulator (to reduce the influence of harmonics, improve system stability and limit the influence of charging current of the capacitor group, etc.); 15 is the capacitor switch group of the single-phase voltage and reactive integrated regulator; 16 is the capacitor group of the single-phase voltage and reactive integrated regulator; 17 is the secondary parallel reactive compensation winding of the single-phase voltage and reactive integrated regulator; 18 is the parallel primary excitation winding and secondary parallel reactive compensation winding core of the single-phase voltage and reactive integrated regulator; 19 is the parallel primary excitation winding of the single-phase voltage and reactive integrated regulator.

[0023] Attached Figure 6 The symbols of the components are as follows: 1 is the parallel energy-taking winding of the single-phase voltage and reactive power integrated regulator; 2 and 3 are the iron core of the single-phase voltage and reactive power integrated regulator; 4 is the single-phase voltage regulating coil ( Figure 4 7-tap coil is taken as an example); 5 is a single-phase voltage and reactive power integrated regulator connected in series with the voltage regulating winding; 6 is a single-phase tap switch ( Figure 6 In the figure, a 7-speed tap changer is taken as an example. The specific number of taps can be arbitrarily configured according to actual needs. If the adjustment accuracy requirement is high, the number of taps can be increased. If the adjustment accuracy requirement is not high, the number of taps can be reduced to control the overall volume, weight and cost of the device). The single-phase voltage regulating coil 5 is connected in series with the single-phase tap changer 6 to form a single-phase voltage and reactive integrated regulator series voltage regulating winding; 7 is a single-phase voltage and reactive integrated regulator parallel reactive compensation winding; 8 is a capacitor protection reactor (reducing harmonic effects, improving system stability and limiting the effects of capacitor bank charging current, etc.); 9 is a capacitor switch group; 10 is a capacitor bank; k1, k2, k3, k4, and k5 are capacitor bank switches respectively. When the switching capacity is required to be 100%, all switches are closed, and in other states, regulation within the capacity range of 0%-100% can be achieved ( Figure 6Taking 5 groups of switch capacitor groups as an example, the specific capacitor combination configuration capacity can be arbitrarily configured according to actual needs. If the adjustment accuracy requirement is high, the number of switches and capacitor groups can be increased. If the adjustment accuracy requirement is not high, the number of switches and capacitor groups can be reduced to control the overall volume, weight and cost of the device. At the same time, the wiring can be Y-connected or Δ-connected according to actual conditions).

[0024] Attached Figure 7 The symbols of the components are as follows: 401 is the excitation parallel module of the A-phase voltage and reactive power integrated regulator; 402 is the series voltage regulation module of the A-phase voltage and reactive power integrated regulator; 403 is the parallel reactive power compensation module of the A-phase voltage and reactive power integrated regulator.

[0025] Attached Figure 8 The symbols of the components are as follows: 101, 201, 301 are the A-phase, B-phase, and C-phase windings of the voltage and reactive power integrated regulator respectively; 102, 202, 302 are the A-phase, B-phase, and C-phase iron cores of the voltage and reactive power integrated regulator respectively; 103, 203, 303 are also the A-phase, B-phase, and C-phase iron cores of the voltage and reactive power integrated regulator; 104, 204, 304 are the three-phase voltage regulating coils ( Figure 8 In the figure, a 7-speed tap changer is taken as an example. The specific number of taps can be arbitrarily configured according to actual needs. If the regulation accuracy requirement is high, the number of taps can be increased. If the regulation accuracy requirement is not high, the number of taps can be reduced to control the overall volume, weight and cost of the device); 105, 205, and 305 are three-phase voltage and reactive power integrated regulators connected in series with voltage regulating windings; 106, 206, and 306 are three-phase tap changers ( Figure 6 7-speed tap changer is taken as an example), 107, 207, 307 are three-phase voltage reactive power integrated regulator parallel reactive power compensation winding; 108, 208, 308 are current limiting reactors; 109, 209, 309 are capacitor switch groups; 110, 210, 310 are capacitor groups. When the switching capacity needs to be 100%, all switches are closed, and the capacity can be adjusted within the range of 0%-100% in other states ( Figure 8 Taking 5 groups of switch capacitor groups as an example, the specific capacitor combination configuration capacity can be arbitrarily configured according to actual needs. If the adjustment accuracy requirement is high, the number of switches and capacitor groups can be increased. If the adjustment accuracy requirement is not high, the number of switches and capacitor groups can be reduced to control the overall volume, weight and cost of the device. At the same time, the wiring can be Y-connected or Δ-connected according to actual conditions). DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] See also Figures 1 to 8 The present invention includes two types of typical preferred embodiments: (1) a single-phase voltage and reactive power integrated regulator topology and (2) a three-phase voltage and reactive power integrated regulator topology. In order to better illustrate the specific implementation methods of the two types of typical preferred embodiments, the single-phase topology embodiment is introduced first, and then the three-phase topology embodiment is introduced according to the logic from simple to complex.

[0028] (1) A preferred embodiment of a single-phase voltage and reactive power integrated regulator topology circuit, see Figure 1 , Figure 3 , Figure 4 , Figure 5 , Figure 6 ,Depend on Figure 1 As shown, this single-phase voltage and reactive power integrated regulator topology circuit is connected in series between the power supply line and the object to be regulated, located at the end or middle of the line, and is suitable for single-phase terminal power users with a large power supply radius within the substation area; the nature of the terminal load can be power load, distributed power generation, or a combination of any capacity ratio of power load and distributed power source.

[0029] Due to the large power supply radius, when the terminal power load current is large, the line voltage drop causes the terminal load voltage to be low. If the voltage deviation index exceeds the lower limit, there is a need for boost regulation; when the terminal distributed power generation output is large, the line voltage difference causes the terminal voltage to be high. If the voltage deviation index exceeds the upper limit, there is a need for step-down regulation; at the same time, in this application scenario or other application scenarios, due to the influence of line impedance and transformer reactive loss, the line reactive current is too high, which seriously affects the power supply efficiency; at this time, the single-phase voltage and reactive integrated regulator topology provided by the present invention is a good embodiment suitable for this scenario.

[0030] The principle diagram of this single-phase voltage and reactive power integrated regulator topology circuit is as follows: Figure 5As shown, the closed iron core magnetic circuit realizes the power conversion between the energy taking winding 11 and the voltage regulating winding 12; the head end A and the end X of the energy taking winding 11 are respectively connected in parallel to the live wire and the neutral wire of the power supply line; the head end A1 of the voltage and reactive power integrated regulator series voltage regulating winding 12 is the input terminal connected to the outside, which will be used to connect the live wire output terminal of the line side in actual application, and the end of the voltage regulating winding 3 is first connected to the head end A of the energy taking winding 2 inside the device to form a common end as the output terminal A2 for external connection, which will be used to connect the live wire input terminal of the load side in actual application.

[0031] The electrical connection details of the series voltage regulating winding in this single-phase voltage and reactive power integrated regulator topology circuit are as follows: Figure 6 As shown, a 7-tap regulating coil is taken as an example (the specific number of taps can be arbitrarily configured according to actual needs. If the regulation accuracy requirement is high, the number of taps can be increased. If the regulation accuracy requirement is not high, the number of taps can be reduced to control the overall volume, weight and cost of the device); the tap numbers of the regulating coil 4 are ① to ⑦, and the head end A of the energy-taking winding 2 is connected to the midpoint position of the regulating coil 4 (i.e., the tap ④) to form a common point. At the same time, the output end A2 and the tap ④ of the regulating winding 4 connected to the outside are led out from this common point. For the regulating winding, this can form a high and low voltage regulation The same regulation range, for example: when there is a voltage reduction requirement, the tap position is at ①-③; when there is a voltage increase requirement, the tap position is at ⑤-⑦; when there is no conditional requirement, the tap position is at ④.

[0032] If the high and low voltage regulation ranges are different, for example, the voltage regulating winding is required to have a larger step-down range and a smaller step-up range, then the common end is adjusted in the direction of increasing the tap number, otherwise, it is adjusted in the direction of decreasing the tap number; if only step-down regulation is required, the common end is connected to tap number ⑦, and if only step-up regulation is required, the common end is connected to tap number ①.

[0033] Each tap ① to ⑦ of the regulating coil is connected to the terminals ① to ⑦ of the 7-speed single-phase tap changer 6 through conductors. The common terminal ⑧ of the single-phase tap changer 6 serves as the input terminal A1 of the single-phase voltage regulating winding. The input terminal A1 and the output terminal A2 of the regulating coil 4 constitute a single-phase voltage regulating winding 3 that can be connected in series to the front end of the object to be regulated. When the common terminal ⑧ of the single-phase tap changer 6 is connected to the position of the tap changer ①, the voltage across A1A2 of the single-phase voltage regulating winding 5 is the voltage difference between the taps ① and ④ of the voltage regulating coil. According to the same-name terminal relationship between the energy-taking winding 1 and the voltage regulating coil 4, When looking toward the end-user along the power supply line, it is equivalent to voltage reduction regulation, which is suitable for regulation scenarios when the voltage of the end-user is high.

[0034] When the common terminal ⑧ of the single-phase tap changer 5 is connected to the position of the tap changer ⑦, the voltage across A1A2 of the single-phase voltage regulating winding 3 is the voltage difference between the voltage regulating coil taps ⑦ and ④. According to the same-name terminal relationship between the energy-taking winding 1 and the voltage regulating coil 4, When looking toward the end power user along the power supply line, it is equivalent to boost regulation, which is suitable for the regulation scenario when the voltage of the end power user is low; when the common terminal ⑧ of the single-phase tap changer 6 is connected to the position of the tap changer ④, the voltage difference across A1A2 of the single-phase voltage regulating winding 5 is zero, which meets the moment when the voltage of the end power user is qualified and no adjustment is required.

[0035] The electrical connection details of the parallel reactive compensation winding in this single-phase voltage reactive integrated regulator topology circuit are as follows: Figure 6 As shown, under the premise that the number of turns of winding 1 and winding 7 remains unchanged, the parallel reactive power compensation winding has a basically fixed voltage. The reactive power injected into the bus is affected by the capacitance and reactance. At this time, the reactive power injected is: Q = U 2 ωC-U 2 / (ωL), by controlling switches k1, k2, k3, k4, and k5, the size of the capacitor C in the parallel reactive compensation module can be affected. When the switching capacity needs to be 100%, all switches are closed. In other states, the capacity can be adjusted within the range of 0%-100% (taking 5 groups of switch capacitors as an example, the specific capacitor combination configuration capacity can be arbitrarily configured according to actual needs. If the adjustment accuracy requirement is high, the number of switches and capacitor groups can be increased. If the adjustment accuracy requirement is not high, the number of switches and capacitor groups can be reduced to control the overall volume, weight, and cost of the device. At the same time, the wiring can be Y-connected or Δ-connected according to actual conditions), thereby affecting the reactive amount of the injected line, realizing dynamic compensation of the reactive loss of the line and transformer, and improving the power supply efficiency.

[0036] (2) A preferred embodiment of a three-phase voltage and reactive power integrated regulator topology circuit, see Figure 2 , Figure 7 and Figure 8 ,Depend on Figure 2 As shown, this three-phase voltage and reactive power integrated regulator topology circuit is connected in series between the power supply line and the object to be regulated, that is, it is located at the end of the line and in front of the distribution transformer of the object to be regulated. It is suitable for distribution stations with a large power supply radius of the distribution line, distributed power supply stations, and combinations of distribution stations and distributed power sources with any capacity ratio.

[0037] Due to the long distribution lines and large power supply radius, when the power load current of the terminal distribution station area is large, the line voltage drop causes the terminal load voltage to be low. If the voltage deviation index exceeds the lower limit, there is a need for boost regulation; when the terminal distributed power station has a large power generation output, the voltage at the end of the line rises, causing the terminal voltage to be high. If the voltage deviation index exceeds the upper limit, there is a need for step-down regulation; at the same time, in this application scenario or other application scenarios, due to the influence of line impedance and transformer reactive loss, the line reactive current is too high, which seriously affects the power supply efficiency; the three-phase voltage and reactive integrated regulator topology provided by the present invention is a good embodiment suitable for this scenario.

[0038] The schematic diagram of the three-phase electromagnetic series voltage regulator topology circuit is as follows: Figure 7 As shown, the closed iron core magnetic circuit realizes the power conversion between the three-phase energy taking winding 401 and the three-phase voltage regulating winding 402; the first ends A, B, and C of each phase winding of the three-phase energy taking winding are respectively connected in parallel to the live wire of the distribution line; the ends X, Y, and Z of each phase winding converge into a neutral point N to realize the star connection of the three-phase energy taking winding. According to the needs of the application, the three-phase energy taking winding can also adopt a delta connection. Even in order to meet the needs of certain special applications, the three-phase energy taking winding can also adopt connection group connections with other points; the first ends A1, B1, and C1 of the three-phase voltage regulating winding 402 are input terminals connected to the outside, and will be used to connect the live wire output terminal on the line side in actual applications; the end of the three-phase voltage regulating winding 8 is first connected to the first ends A, B, and C of the three-phase energy taking winding 7 in the equipment to form a common end, and serves as the three-phase output terminals A2, B2, and C2 connected to the outside. In actual applications, it will be used to connect the input ends of each live wire on the load side.

[0039] The electrical wiring details of the three-phase voltage regulating winding in this three-phase electromagnetic series voltage regulator topology circuit are as follows: Figure 8 As shown, the A-phase regulating coil with 7 taps is taken as an example: the tap numbers of the A-phase regulating coil 105 are ① to ⑦, the head end A of the A-phase energy extraction winding 101 is connected to the midpoint of the regulating coil 105 (i.e., the tap ④ of the A-phase regulating coil 104) to form a common point, and at the same time, the output end A2 of the A-phase regulating winding 105 connected to the outside and the tap ④ of the A-phase regulating coil 105 are led out from this common point. For the A-phase regulating winding, the same high and low voltage ranges can be adjusted in this way. For example: when there is a voltage reduction requirement, the tap position is at ①-③; when there is a voltage increase requirement, the tap position is at ⑤-⑦; when there is no conditional requirement, the tap position is at ④ (the specific number of taps can be arbitrarily configured according to actual needs. If the regulation accuracy requirement is high, the number of taps can be increased. If the regulation accuracy requirement is not high, the number of taps can be reduced to control the overall volume, weight and cost of the device).

[0040] If the high and low voltage regulation ranges are different, for example, the voltage regulating winding is required to have a larger step-down range and a smaller step-up range, the common end is adjusted in the direction of increasing the tap number, otherwise, it is adjusted in the direction of decreasing the tap number; if only step-down regulation is required, the common end is connected to tap number ⑦, and if only step-up regulation is required, the common end is connected to tap number ①.

[0041] The taps ① to ⑦ of the A-phase regulating coil 105 are connected to the terminals ① to ⑦ of the 7-speed A-phase tap switch 106 through conductors. The common terminal ⑧ of the A-phase tap switch 106 serves as the input terminal A1 of the A-phase voltage regulating winding 104. The input terminal A1 and the output terminal A2 of the A-phase regulating coil 104 constitute the A-phase winding port A1A2 of the series voltage regulating winding. When the common terminal ⑧ of the A-phase tap switch 106 is connected to the position of the tap switch ①, the voltage across A1A2 of the A-phase voltage regulating winding 104 is the voltage difference between the taps ① and ④ of the A-phase voltage regulating coil. According to the same-name terminal relationship between the energy-taking winding 101 and the voltage regulating coil 105, it can be known that That is, when looking along the power supply line toward the end power user, it is equivalent to step-down regulation, which is suitable for the regulation scenario when the voltage of the end power user is high; when the common terminal ⑧ of the A-phase tap switch 106 is connected to the position of the tap switch ⑦, the voltage across A1A2 of the A-phase voltage regulating winding 104 is the voltage difference between the voltage regulating coil taps ⑦ and ④. According to the same-name terminal relationship between the energy-taking winding 101 and the voltage regulating coil 105, it can be known that That is, when looking toward the end power user along the power supply line, it is equivalent to boost regulation, which is suitable for regulation scenarios when the voltage of the end power user is low; when the common terminal ⑧ of the A-phase tap switch 106 is connected to the position of the tap switch ④, the voltage difference between the two ends of A1A2 of the A-phase voltage regulating winding 105 is zero, which meets the situation that no regulation is required when the voltage of the end power user is qualified.

[0042] The electrical wiring details of the B-phase and C-phase voltage regulating windings in the three-phase voltage regulating windings in this three-phase electromagnetic series voltage regulator topology circuit are the same as those of the A-phase voltage regulating winding. The common terminal ⑧ of the B-phase tap switch 206 serves as the input terminal B1 of the B-phase voltage regulating winding 205, and the input terminal B1 and the output terminal B2 of the B-phase regulating coil 205 constitute the B-phase winding port B1B2 of the series voltage regulating winding; the common terminal ⑧ of the C-phase tap switch 306 serves as the input terminal C1 of the C-phase voltage regulating winding 305, and the input terminal C1 and the output terminal C2 of the C-phase regulating coil 305 constitute the C-phase winding port C1C2 of the series voltage regulating winding.

[0043] At this time, A1A2, B1B2, and C1C2 respectively constitute the A, B, and C phase windings of the three-phase series voltage regulating winding; the end X of the A phase energy taking winding 101, the end Y of the B phase energy taking winding 201, and the end Z of the C phase energy taking winding 301 are connected to a common point N as the neutral point of the three-phase windings, thereby forming a three-phase parallel energy taking winding.

[0044] The electrical connection details of the parallel reactive power compensation winding in this three-phase voltage reactive power integrated regulator topology circuit are as follows: Figure 8 As shown, under the premise that the number of turns of windings 101, 201, 301 and windings 107, 207, 307 remains unchanged, the parallel reactive power compensation winding has a basically fixed voltage magnitude, and the reactive power injected into the bus is affected by the capacitance and reactance magnitudes. At this time, the reactive power injected is: Q = 3·(U 2 ωC-U 2 / (ωL)), by controlling switches k1, k2, k3, k4, and k5, the size of the capacitor C in the parallel reactive compensation module can be affected. When the switching capacity needs to be 100%, all switches are closed, and in other states, the capacity can be adjusted within the range of 0%-100% (taking 5 groups of switch capacitors as an example, the specific capacitor combination configuration capacity can be arbitrarily configured according to actual needs. If the adjustment accuracy requirement is high, the number of switches and capacitor groups can be increased. If the adjustment accuracy requirement is not high, the number of switches and capacitor groups can be reduced to control the overall volume, weight, and cost of the device. At the same time, the wiring can be Y-connected or Δ-connected according to actual conditions), thereby affecting the reactive amount of the injected line, realizing dynamic compensation of the reactive loss of the line and the transformer, and improving the power supply efficiency.

[0045] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A topological circuit for a voltage and reactive power integrated regulator based on the principle of equivalent electrical distance regulation, comprising a closed iron core magnetic circuit, a parallel primary excitation winding, a multi-tap secondary coil, an on-load tap-changer, a capacitor switching switch, a current-limiting reactor, a capacitor, a housing, and accessories; the multi-tap secondary coil is connected to the on-load tap-changer to form a secondary series voltage-regulating winding; the capacitor, the current-limiting reactor, and the capacitor switching switch are connected to form a secondary parallel reactive power compensation winding; in a specific application, the primary winding is connected in parallel to the power supply and distribution line, the secondary series voltage-regulating winding is connected in series between the power supply and distribution line and the regulated object, and the secondary parallel reactive power compensation winding is connected in parallel to the line via the primary winding; the circuit is characterized by: In the series voltage regulation and parallel reactive power compensation windings, the closed iron core magnetic circuit realizes voltage conversion and power conversion between the primary winding and the secondary coil. In the secondary series voltage regulation winding, the voltage phasor is established between the taps of the secondary coil, and the secondary winding voltage is then adjusted by the on-load tap changer. In the secondary parallel reactive power compensation winding, the principle that the current direction of the parallel capacitor and the line inductive reactive power differs by 180 degrees is utilized to connect capacitors of appropriate capacity to achieve reactive power balance, and the discrete adjustment of the connected line reactive power is achieved by the on-off state of the capacitor branch switch.

2. The voltage and reactive power integrated regulator topology circuit based on the equivalent electrical distance regulation principle according to claim 1 is characterized in that: The primary winding is connected in parallel to the power supply and distribution line, the secondary series voltage regulating winding is connected in series to the power supply and distribution line, the secondary parallel reactive compensation winding is connected in parallel to the line through the primary winding, and the specific electrical position of the three-phase or single-phase reactive integrated regulator is between the power supply and distribution line and the regulated object.

3. According to the topological circuit of a voltage and reactive power integrated regulator based on the principle of equivalent electrical distance regulation described in claim 1, the secondary series voltage regulating winding topology is characterized by: the secondary series voltage regulating winding is composed of a multi-tap secondary coil connected to an on-load tap-changing switch, and is connected in series to the power supply and distribution line. The voltage conversion and power conversion between the primary winding and the secondary regulating winding are realized through a closed iron core magnetic circuit. The series voltage at the line access point is increased or decreased by selecting the on-load tap-changing switch.

4. According to the topology circuit of a voltage and reactive power integrated regulator based on the principle of equivalent electrical distance regulation described in claim 1, the topology feature of its secondary parallel reactive power compensation winding is: the secondary parallel reactive power compensation winding and the current limiting inductor form a branch, the branch capacitance is affected by the switching state, and the voltage and power conversion between the primary winding and the secondary parallel reactive power compensation winding is realized through a closed iron core magnetic circuit. At this time, the reactive power consumed by the secondary parallel reactive power compensation winding is exchanged through the primary winding and the line.

5. The secondary series voltage regulating winding according to claim 2 is connected to a power supply and distribution line, characterized in that: The three-phase windings on the primary side can be connected to form a transformer connection group suitable for various requirements, and connected in parallel to the live wire of the three-phase power supply and distribution line. The three-phase secondary regulating windings are directly connected in series to the power supply and distribution line. Among them, the first end of each phase of the primary winding A, B, and C is connected to the center position of each phase of the multi-tap secondary coil to form a common point of each phase. From the common point of each phase, the series output ends of each phase of the secondary coil are connected to the outside, namely the winding ends A2, B2, C2 and the center tap of the multi-tap secondary coil, so that the multi-tap secondary coil can achieve the same regulation of step-up and step-down. If the step-up and step-down regulation ranges are different, the common end of each phase is adjusted in the direction of decreasing or increasing the tap number; the multi-tap secondary coil of each phase is connected to the corresponding phase on-load tap-changer to form a three-phase secondary regulation winding, and the common end of each phase on-load tap-changer serves as the input end of the secondary voltage regulating winding, that is, the winding head end A1, B1, C1. Therefore, the input ends A1, B1, C1 and the output ends A2, B2, C2 of the secondary voltage regulating winding constitute the secondary regulation three-phase windings A1A2, B1B2, C1C2 respectively.

6. The secondary parallel reactive compensation winding according to claim 1 is characterized in that: Under the premise that the number of turns of the primary winding and the secondary winding remains unchanged, the size of the capacitor C in the parallel reactive compensation module can be affected by controlling the switch state, thereby affecting the reactive power injected into the line by the secondary parallel winding: Q = 3 (U 2 ωC-U 2 / (ωL)), dynamic reactive power compensation is achieved by changing the switch state.

7. The secondary series voltage regulating winding according to claim 1, characterized in that: The three-phase windings on the primary side can be connected into a transformer connection group suitable for various requirements and connected in parallel to the live wire of the three-phase power supply and distribution line. The three-phase secondary regulating windings are directly connected in series to the power supply and distribution line. Among them, the on-load tap-changer and the polarity switch can be combined to achieve graded voltage regulation by the on-load tap-changer, and positive and negative bidirectional control by the polarity switch, so as to achieve high and low voltage regulation of single-phase or three-phase at the end of the line.

8. According to the on-load tap-changer of claim 1, if the regulation accuracy requirement is high, the number of taps can be increased; if the regulation accuracy requirement is not high, the number of taps can be reduced to control the overall size, weight and cost of the device.

9. According to the branch capacitor described in claim 1, if the adjustment accuracy requirement is high, the number of its switching switches and capacitor banks can be increased; if the adjustment accuracy requirement is not high, the number of its switching switches and capacitor banks can be reduced to control the overall volume, weight and cost of the device. At the same time, its wiring can adopt Y connection or Δ connection according to actual conditions.

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