±500kV flexible DC converter transformer with valve sleeve arranged outdoors

Abstract

The application discloses a valve sleeve outdoor arrangement of a +500kV flexible direct current converter transformer, which comprises an oil tank, an on-load tap changer and a cooler, has a single-phase double-winding structure, and is provided with coils sleeved on first and second middle core columns, and two outer side core columns only serve as a magnetic flux loop; valve side coils and network side coils on the two core columns are connected in parallel respectively; the arrangement order of the coils on each core column is as follows: starting from the side of the core, a voltage regulating coil, a network side coil and a valve side coil; the coils on the first core column are all left-wound, and the coils on the second core column are all right-wound. The application is the first flexible direct current product with the largest capacity and the highest voltage grade in China, has high overall insulation level, and the overall structure satisfies the mechanical strength and short-circuit resistance of the product, reduces the design and operation difficulty of the main insulation structure, improves the safety and reliability of the product, can realize a major technical breakthrough of the ultra-high voltage flexible direct current converter transformer, and fills the domestic blank.

Description

TECHNICAL FIELD

[0001] The present application relates to a transformer manufacturing technology, in particular to a ±500kV flexible DC converter transformer with valve bushing outdoor arrangement. BACKGROUND

[0002] The flexible DC power transmission technology is a new generation of DC power transmission system based on power converter and pulse width modulation technology. The flexible DC power transmission plays an increasingly important role in the fields of new energy grid connection and consumption, asynchronous networking, island power supply and long distance power transmission. The voltage level of the valve side of the previous flexible DC engineering converter transformer is at most ±320kV. At present, there is no large-capacity and high-voltage flexible DC converter transformer exceeding ±320kV. The original high-voltage flexible DC converter transformer valve side outlet insulation structure is complex, the manufacturing cost is high, the installation is difficult, and the transformer volume and land occupation are large. At the same time, the design and operation of the main insulation structure of the original transformer are difficult, which affects the safety and reliability of the product. SUMMARY

[0003] In view of the problems of low voltage level of the valve side of the flexible DC engineering converter transformer in the prior art, the inability to meet the demand of flexible DC loop network engineering, and the complex valve side outlet insulation structure and high manufacturing cost, the present application aims to provide a ±500kV flexible DC converter transformer with valve bushing outdoor arrangement, which can meet the engineering demand, has a simple structure and low cost.

[0004] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0005] The present application provides a ±500kV flexible DC converter transformer with valve bushing outdoor arrangement, which comprises an oil tank, a load tap changer and a cooler, has a single-phase double-winding structure, a coil is sleeved on the middle first to second core columns, and the two outer side columns are only used as a magnetic flux return circuit. The valve side coil and the grid side coil on the two core columns are connected in parallel respectively. The arrangement order of the coils on each core column is as follows from the side of the core: voltage regulating coil-grid side coil-valve side coil. The coils on the first core column are all left-wound, and the coils on the second core column are all right-wound.

[0006] The valve side coil adopts end outlet radial horizontal lead-out, and is electrically connected with the original coil of the valve side coil through an aluminum pipe and a copper brush wire. The upper outlet head of the valve side coil on the first core column is connected with a lead cable, penetrates through a shielding pipe, passes through a valve side outlet device, penetrates through a tank cover and is vertically led out to the valve side riser seat, and is connected with a 500kV bushing of phase a. The lower outlet head of the valve side coil on the second core column is connected with a lead cable, penetrates through a shielding pipe, passes through a valve side outlet device, penetrates through a tank cover and is vertically led out to the valve side riser seat, and is connected with a 500kV bushing of phase b.

[0007] Valve side outlet device adopts multi-layer oil gap partitioned forming paper pulp shielding in valve side sleeve tail equalizing ball accessory, equalizing ball below part gradually transitions, shielding tube is wrapped with insulation piece, and shielding ring is placed at valve side riser and tank cover connection place.

[0008] First and second column net side coil first end outlet is connected together and is connected with A phase 330kV sleeve, net side coil end outlet is connected with voltage regulating coil and is connected into each column tap switch respectively; adjusted tap line is connected with B phase sleeve through tap switch leading-out cable.

[0009] Net side outlet is led out from tank cover through 330kV sleeve, valve side ±500kV sleeve is led out from tank cover long axis two sides vertically, and is arranged outside valve hall.

[0010] 1.The valve sleeve outdoor arrangement ±500kV flexible DC converter transformer provided by the application is the first flexible DC product with the largest capacity and the highest voltage level in China, has high overall insulation level, and overall structure meets mechanical strength and short circuit resistance of the product; while meeting product performance, reduces design and operation difficulty of main insulation structure, improves safety and reliability of the product, can realize significant technical breakthrough of ultra-high voltage flexible DC converter transformer, and fills the domestic blank.

[0011] 2.The valve side sleeve in the application does not extend into the valve hall, is vertically arranged outdoors, makes the structure of the converter transformer compact, reduces land occupation area, the valve side lead-out wire structure is simple and compact, reduces the number of forming pieces, reduces product design cost, reduces work load of each process, reduces manufacturing cost and engineering cost, and improves manufacturing enterprise benefit. DETAILED DESCRIPTION

[0012] Fig. 1 It is a front view of the converter transformer of the application;

[0013] Fig. 2 It is a top view of the converter transformer of the application;

[0014] Fig. 3 It is a left view of the converter transformer of the application;

[0015] Fig. 4 It is a schematic diagram of internal winding arrangement and connection of the converter transformer of the application;

[0016] Fig. 5 It is a valve outlet diagram of the converter transformer of the application;

[0017] Fig. 6 It is a schematic diagram of internal wiring of the converter transformer of the application.

[0018] Wherein, 1 is a converter transformer oil tank, 2 is a load tap changer, 3 is a cooler, 4 is a network side riser, 5 is a network side bushing, 6 is a valve side riser, 7 is a valve side bushing, 8 is a neutral point riser, 9 is a neutral point bushing, 10 is a voltage regulating coil, 11 is a network side coil, 12 is a valve side coil, 13 is a valve side outlet device, 14 is a shaped paper pulp piece, 15 is a shielding tube, and 16 is a shielding ring. DETAILED DESCRIPTION

[0019] The application will be further described below in conjunction with the accompanying drawings of the specification.

[0020] As shown in the drawings, Figs. 1-3 the application provides a ±500kV flexible DC converter transformer with valve bushing outdoor arrangement, which comprises an oil tank 1, a load tap changer 2, and a cooler 3, has a single-phase double-winding structure, and has coils on middle first and second core columns (i.e. column 1 and column 2) and does not have coils on two outer side columns as a magnetic flux circuit. The valve side coil 12 and the network side coil 11 on the two core columns are respectively connected in parallel. The arrangement order of the coils on each core column is, from the side of the core, voltage regulating coil 10-network side coil 11-valve side coil 12. The coils on the first core column are all left-wound, and the coils on the second core column are all right-wound. Fig. 1

[0021] In the embodiment, the load tap changer 2 is placed inside the left side of the transformer oil tank 1, and the cooler 3 is arranged at the short axis side of the transformer oil tank 1. There is one network side bushing 5 and one neutral point bushing 9, which are arranged at the cooler side. The network side bushing 5 is obliquely led out through the network side riser 6 fixed on the upper part of the converter transformer oil tank 1; the neutral point bushing 9 is vertically led out through the neutral point riser 8 fixed on the upper part of the converter transformer oil tank 1; and the two valve side bushings 7 are vertically led out through the valve side riser 6 fixed on the tank cover of the converter transformer oil tank 1 at the side far away from the cooler.

[0022] As shown in the drawings, Fig. 4 the application adopts a single-phase double-winding structure, the core is a single-phase four-column structure, coils are sleeved on middle first and second core columns (i.e. column 1 and column 2), and the two outer side columns are used as a magnetic flux circuit without coils. The valve side coil and the network side coil of column 1 and column 2 are respectively connected in parallel. The arrangement order of the coils is, from the core, “voltage regulating coil 10-network side coil 11-valve side coil 12”, all the coils on column 1 are right-wound, and all the coils on column 2 are left-wound.

[0023] As shown in the drawings, Fig. 5 ​As shown in Figure 6, in this invention, the valve-side coil 12 adopts a radially horizontal lead-out design. The valve-side coils 12 on columns 1 and 2 are connected to the original coil wire via high-frequency welding using aluminum tubing 15 and copper brush wire. The upper end of the valve-side coil 12 on column 1 is cold-pressed and welded to the lead cable, then passes through the shielding tube 15, through the valve lead-out device 13, and vertically leads out through the box cover to the valve-side riser seat 6, connecting to the a-phase valve-side sleeve 7. The lower end of the valve-side coil 12 on column 2 is cold-pressed and welded to the lead cable, then passes through the valve lead-out device 13, and vertically leads out through the box cover to the valve-side riser seat 6, connecting to the b-phase valve-side sleeve 7.

[0024] The valve-side outlet device 13 uses a multi-layer oil gap segmented molded pulp part 14 for shielding the equalizing ball accessory at the tail of the valve-side bushing. The part below the equalizing ball gradually transitions, and the shielding aluminum tube is wrapped with thick insulation. A shielding ring 15 is placed at the connection between the valve-side riser seat and the box cover to improve the electric field strength of the valve lead to ground, so as to reduce the partial discharge level of the product under various AC and DC voltages.

[0025] like Fig. 6 As shown, in this invention, the first ends of the grid-side coils 11 on columns 1 and 2 are connected together to the A-phase grid bushing 5. The last ends of the grid-side coils 11 on columns 1 and 2, together with the voltage regulating coils 10, are connected to the tap changer 2 of each column to achieve on-load voltage regulation and tap adjustment. The adjusted tap line is connected to the neutral point bushing 9 of the B-phase neutral point via a cable led out from the tap changer.

[0026] This invention will be applied to the world's first flexible DC ring network project with the highest valve-side voltage level, at ±500kV. The valve-side bushing does not extend into the valve hall and is arranged vertically outdoors. The transformer size is reduced, the structure is simple, and the floor space is saved, achieving a major technological breakthrough in ultra-high voltage flexible DC converter transformers.

Claims

1. A valve bushing outdoor arrangement of ±500 kV flexible DC converter transformer, comprising an oil tank, an on-load tap changer and a cooler, characterized in that: The valve side coil adopts end outgoing line radial horizontal lead-out, and is electrically connected with the original coil through copper brush line of aluminum pipe. The upper outgoing head of the valve side coil on the first core column is connected with lead cable, penetrates through the shielding pipe, passes through the valve side outgoing line device, penetrates through the tank cover, is vertically led out to the valve side elevated seat, and is connected with the 500kV bushing of a phase. The valve side coil on the second core column is connected with lead cable, penetrates through the shielding pipe, passes through the valve side outgoing line device, penetrates through the tank cover, is vertically led out to the valve side elevated seat, and is connected with the 500kV bushing of b phase. The valve side outgoing line device adopts the shielding of the multi-layer oil gap segmented formed paper pulp at the tail of the valve side bushing ball accessory, and the part below the ball is gradually transitioned. The shielding pipe is wrapped with insulation, and the shielding ring is placed at the connection between the valve side elevated seat and the tank cover. The network side outgoing line is led out from the tank cover through the 330kV bushing, and the valve side ±500kV bushing is vertically led out from the long axis of the tank cover, and is arranged outside the valve hall.

2. The valve bushing outdoor arrangement ± 500 kV flexible DC converter transformer according to claim 1, characterized in that: The first end outgoing head of the network side coil on the first and second columns is connected together and connected with the 330kV bushing of a phase. The end outgoing head of the network side coil is connected with the regulating coil, and is respectively connected into the tapping switch of each column. The adjusted tapping line is connected with the neutral point B phase bushing through the lead cable of the tapping switch.

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