Electromagnetic hybrid flexible networking device

Abstract

The application provides an electromagnetic hybrid flexible networking device for a three-phase power grid, which is a combination of a three-phase phase shifter and a small-capacity UPFC regulating device, and comprises three excitation windings, nine regulating windings with taps, three sets of small-capacity UPFC regulators and three groups of series windings; the three sets of small-capacity UPFC regulators are the same; the connection method of the networking device and the power grid specifically comprises that the connection element of the networking device and each phase of the power grid comprises one excitation winding, three regulating windings with taps, one set of small-capacity UPFC and one group of series windings; one winding is selected from each of the three regulating windings of each phase as a phase-modulating coil group and is connected, specifically: the selected three windings are connected in series at the head and tail, and three groups of phase-modulating coil groups are formed in total; the three excitation windings are connected in parallel between the three-phase bus of the power grid and the ground in a star connection mode; and the application can achieve the purpose of reducing the closed-loop impact current.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment technology, and in particular to an electromagnetic hybrid flexible networking device. Background Technology

[0002] In power distribution network operation, planned power outages caused by network upgrades, business expansion, and scheduled maintenance account for more than 70% of user outage time. Users with high power quality requirements will switch between primary and backup power sources through loop closing to achieve uninterrupted power supply. However, loop closing may cause voltage phase and amplitude jumps at various nodes of the line, resulting in voltage oscillations, which may lead to malfunctions or damage to relay protection devices.

[0003] Therefore, a new type of flexible networking device is needed to alleviate this problem. Summary of the Invention

[0004] This invention proposes an electromagnetic hybrid flexible networking device that can reduce the closing-loop inrush current.

[0005] The present invention adopts the following technical solution.

[0006] An electromagnetic hybrid flexible grid-connecting device is used in a three-phase power grid. It is a combination of a three-phase phase shifter and a small-capacity UPFC regulator, including three excitation windings, nine regulating windings with taps, three sets of small-capacity UPFC regulators, and three sets of series windings; the three sets of small-capacity UPFC regulators are all identical.

[0007] The specific methods for connecting network devices to the power grid include:

[0008] Method A: In the networking device, the connection elements to each phase of the power grid include one excitation winding, three tapped regulating windings, one small-capacity UPFC, and one series winding.

[0009] Method B: Select one winding from each of the three regulating windings in each phase as a phase adjustment coil group and connect them. Specifically, connect the three selected windings end to end to form a total of three phase adjustment coil groups.

[0010] Method C: Connect the three excitation windings in parallel between the three-phase busbar of the power grid and the ground in a star configuration;

[0011] Method D: The small-capacity UPFC regulator draws power from the three-phase phase shifter through the excitation winding, charges the capacitor on the DC bus through single-phase controllable rectification, and converts the DC voltage into the required AC voltage output through a fully controlled inverter.

[0012] Method E: Connect the output sides of the three sets of phase-adjusting coils and the three sets of UPFC regulators in series, and then connect them to the three-phase busbar of the power grid through the series winding to boost the voltage.

[0013] In Method A, the excitation winding of each phase, the three regulating windings, and the excitation side winding of the UPFC are wound on the same phase core.

[0014] Let the excitation winding of phase A be denoted as A, the excitation winding of phase B as B, and the excitation winding of phase C as C; the regulating windings of phase A be denoted as a1, a2, a3, the regulating windings of phase B be denoted as b1, b2, b3, and the regulating windings of phase C be denoted as c1, c2, c3; the UPFC excitation winding of phase A be denoted as UPFC_a, the UPFC excitation winding of phase B be denoted as UPFC_b, and the UPFC excitation winding of phase C be denoted as UPFC_c; the series winding of phase A be denoted as EH_a, the series winding of phase B be denoted as EH_b, and the series winding of phase C be denoted as EH_c.

[0015] The specific adjustment connection method of phase A is as follows: A is wound as the excitation winding on the innermost side of the iron core, and a1, a2, a3, and UPFC_a are wound from top to bottom on the outer side of the excitation winding A. After a1, b1, c1, UPFC_a, and EH_a are connected in series, a complete winding with adjustment function is formed.

[0016] The adjustment and connection methods for phases B and C are the same as those for phase A;

[0017] The excitation windings A, B, and C are connected together and then grounded, forming a star connection.

[0018] Each phase core of the three-phase phase shifter is wound with an excitation winding, three tapped adjustment windings, and an excitation winding for a small-capacity UPFC regulator.

[0019] The regulating winding includes an regulating tap for switching gears via an on-load tap changer.

[0020] The number of taps in the adjusting winding is adjusted according to the actual adjustment range required by the line, with a minimum of two taps and a maximum of six taps.

[0021] The networking device is used for the loop-closing operation of switching between main and backup power supplies during power outages, in order to reduce the loop-closing inrush current.

[0022] Compared with the prior art, the present invention has the following advantages and technical effects:

[0023] This invention combines a traditional transformer-type phase shifter with a UPFC power electronic regulator, overcoming the disadvantage of discrete regulation of the traditional transformer-type phase shifter. At the same time, it reduces the required capacity of the power electronic device, making the regulation more precise (compared to the transformer-type phase shifter) under the same regulation range and capacity, and the equipment cost is lower and the control and manufacturing are simpler (compared to UPFC). Attached Figure Description

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0025] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0026] Figure 2 This is a schematic diagram of the winding arrangement for a single phase. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] As shown in the figure, an electromagnetic hybrid flexible networking device is used in a three-phase power grid. The networking device is a combination of a three-phase phase shifter and a small-capacity UPFC regulator, including three excitation windings, nine regulating windings with taps, three sets of small-capacity UPFC regulators, and three sets of series windings; the three sets of small-capacity UPFC regulators are all the same.

[0030] The specific methods for connecting network devices to the power grid include:

[0031] Method A: In the networking device, the connection elements to each phase of the power grid include one excitation winding, three tapped regulating windings, one small-capacity UPFC, and one series winding.

[0032] Method B: Select one winding from each of the three regulating windings in each phase as a phase adjustment coil group and connect them. Specifically, connect the three selected windings end to end to form a total of three phase adjustment coil groups.

[0033] Method C: Connect the three excitation windings in parallel between the three-phase busbar of the power grid and the ground in a star configuration;

[0034] Method D: The small-capacity UPFC regulator draws power from the three-phase phase shifter through the excitation winding, charges the capacitor on the DC bus through single-phase controllable rectification, and converts the DC voltage into the required AC voltage output through a fully controlled inverter.

[0035] Method E: Connect the output sides of the three sets of phase-adjusting coils and the three sets of UPFC regulators in series, and then connect them to the three-phase busbar of the power grid through the series winding to boost the voltage.

[0036] In Method A, the excitation winding of each phase, the three regulating windings, and the excitation side winding of the UPFC are wound on the same phase core.

[0037] Let the excitation winding of phase A be denoted as A, the excitation winding of phase B as B, and the excitation winding of phase C as C; the regulating windings of phase A be denoted as a1, a2, a3, the regulating windings of phase B be denoted as b1, b2, b3, and the regulating windings of phase C be denoted as c1, c2, c3; the UPFC excitation winding of phase A be denoted as UPFC_a, the UPFC excitation winding of phase B be denoted as UPFC_b, and the UPFC excitation winding of phase C be denoted as UPFC_c; the series winding of phase A be denoted as EH_a, the series winding of phase B be denoted as EH_b, and the series winding of phase C be denoted as EH_c.

[0038] The specific adjustment connection method of phase A is as follows: A is wound as the excitation winding on the innermost side of the iron core, and a1, a2, a3, and UPFC_a are wound from top to bottom on the outer side of the excitation winding A. After a1, b1, c1, UPFC_a, and EH_a are connected in series, a complete winding with adjustment function is formed.

[0039] The adjustment and connection methods for phases B and C are the same as those for phase A;

[0040] The excitation windings A, B, and C are connected together and then grounded, forming a star connection.

[0041] Each phase core of the three-phase phase shifter is wound with an excitation winding, three tapped adjustment windings, and an excitation winding for a small-capacity UPFC regulator.

[0042] The regulating winding includes an regulating tap for switching gears via an on-load tap changer.

[0043] The number of taps in the adjusting winding is adjusted according to the actual adjustment range required by the line, with a minimum of two taps and a maximum of six taps.

[0044] The networking device is used for the loop-closing operation of switching between main and backup power supplies during power outages, in order to reduce the loop-closing inrush current.

[0045] The adjusting winding shown in the figure has four taps and four adjustment positions. In practical applications, the number of positions needs to be configured according to the adjustment range and capacity. It is preferable to have at least two taps and two positions, and at most six taps and six positions. The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An electromagnetic hybrid flexible networking device, characterized in that: The networking device is used in a three-phase power grid and is a combination of a three-phase phase shifter and a small-capacity UPFC regulator. It includes three excitation windings, nine regulating windings with taps, three sets of small-capacity UPFC regulators, and three sets of series windings. All three sets of small-capacity UPFC regulators are identical. The specific methods for connecting network devices to the power grid include: Method A: In the networking device, the connection elements to each phase of the power grid include one excitation winding, three tapped regulating windings, one small-capacity UPFC, and one series winding. Method B: Select one winding from each of the three regulating windings in each phase as a phase adjustment coil group and connect them. Specifically, connect the three selected windings end to end to form a total of three phase adjustment coil groups. Method C: Connect the three excitation windings in parallel between the three-phase busbar of the power grid and the ground in a star configuration; Method D: The small-capacity UPFC regulator draws power from the three-phase phase shifter through the excitation winding, charges the capacitor on the DC bus through single-phase controllable rectification, and converts the DC voltage into the required AC voltage output through a fully controlled inverter. Method E: Connect the output sides of the three sets of phase-adjusting coils and the three sets of UPFC regulators in series, and then connect them to the three-phase busbar of the power grid through the series winding to boost the voltage.

2. The electromagnetic hybrid flexible networking device according to claim 1, characterized in that: In Method A, the excitation winding of each phase, the three regulating windings, and the excitation side winding of the UPFC are wound on the same phase core. Let the excitation winding of phase A be denoted as A, the excitation winding of phase B as B, and the excitation winding of phase C as C; the regulating windings of phase A be denoted as a1, a2, a3, the regulating windings of phase B be denoted as b1, b2, b3, and the regulating windings of phase C be denoted as c1, c2, c3; the UPFC excitation winding of phase A be denoted as UPFC_a, the UPFC excitation winding of phase B be denoted as UPFC_b, and the UPFC excitation winding of phase C be denoted as UPFC_c; the series winding of phase A be denoted as EH_a, the series winding of phase B be denoted as EH_b, and the series winding of phase C be denoted as EH_c. The specific adjustment connection method of phase A is as follows: A is wound as the excitation winding on the innermost side of the iron core, and a1, a2, a3, and UPFC_a are wound from top to bottom on the outer side of the excitation winding A. After a1, b1, c1, UPFC_a, and EH_a are connected in series, a complete winding with adjustment function is formed. The adjustment and connection methods for phases B and C are the same as those for phase A; The excitation windings A, B, and C are connected together and then grounded, forming a star connection.

3. The electromagnetic hybrid flexible networking device according to claim 1, characterized in that: Each phase core of the three-phase phase shifter is wound with an excitation winding, three tapped adjustment windings, and an excitation winding for a small-capacity UPFC regulator.

4. The electromagnetic hybrid flexible networking device according to claim 1, characterized in that: The regulating winding includes an regulating tap for switching gears via an on-load tap changer.

5. The electromagnetic hybrid flexible networking device according to claim 4, characterized in that: The number of taps in the adjusting winding is adjusted according to the actual adjustment range required by the line, with a minimum of two taps and a maximum of six taps.

6. The electromagnetic hybrid flexible networking device according to claim 1, characterized in that: The networking device is used for the loop-closing operation of switching between main and backup power supplies during power outages, in order to reduce the loop-closing inrush current.

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