Double-split 66kV offshore photovoltaic system

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By employing a double-split transformer and multiple circuit breaker configurations in the offshore photovoltaic system, the problems of high cost and unreliability in the existing technology have been solved, and the short-circuit current limitation on the low-voltage side and the bus voltage stability have been achieved, thereby improving the economy and reliability of the system.

CN223744614UActive Publication Date: 2025-12-30QINGDAO TGOOD ELECTRIC

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Patent Information

Application Number: CN202520006180.8
Authority / Receiving Office: CN · China
Patent Type: Utility models(China)
Current Assignee / Owner
Filing Date: 2025-01-03
Publication Date: 2025-12-30
Estimated Expiration: 2035-01-03

AI Technical Summary

Technical Problem

Existing dual-winding offshore photovoltaic booster stations are costly and unreliable, especially in large-scale photovoltaic projects where they are not economically viable. Furthermore, a failure of the booster transformer or power supply equipment will affect power output.

Method used

The system adopts a double-split 66kV offshore photovoltaic system. The transformer has one high-voltage winding and two low-voltage windings. The low-voltage winding is split into two parts and connected to the low-voltage cabinet through copper busbars and cables. Various circuit breakers and instrument transformers are configured to limit short-circuit current and improve system reliability.

Benefits of technology

It effectively limits the short-circuit current on the low-voltage side, saves investment in switchgear, ensures stable bus voltage, avoids the impact of a single branch fault on the operation of other busbars, and improves the economy and reliability of the system.

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Abstract

The utility model belongs to the technical field of offshore photovoltaic systems, and provides a double-split 66kV offshore photovoltaic system which comprises a high-voltage chamber, a transformer chamber and a low-voltage chamber, the high-voltage chamber is connected with one end of the transformer chamber, and the other end of the transformer chamber is connected with the low-voltage chamber; the transformer chamber comprises a double-split transformer, a copper bar and a cable, the double-split transformer is connected with the two low-voltage cabinets in the low-voltage chamber through the copper bar, and the double-split transformer is connected with the V-shaped inflatable cabinet in the high-voltage chamber through the cable. According to the utility model, the problems of uneconomical efficiency of a large 66kV offshore photovoltaic project in the prior art and unreliability of power supply by adopting a double winding and a branch circuit in the prior art can be solved.

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Description

Technical Field

[0001] This utility model belongs to the technical field of marine photovoltaic systems, specifically, it relates to a dual-split 66kV marine photovoltaic system. Background Technology

[0002] With the continuous development of renewable energy, offshore photovoltaic (PV) projects have attracted increasing attention due to their unique advantages. In existing dual-winding offshore PV booster stations, each power generation unit is equipped with a booster transformer. Although this unit wiring structure is simple, its cost is high in large-scale PV projects, resulting in poor overall economic efficiency. Therefore, this approach is typically suitable for projects with dispersed power generation units to reduce line losses and conductor costs. It is not suitable for centralized PV power plants. Furthermore, existing dual-winding offshore PV booster stations use a single branch power supply, which introduces a degree of unreliability. If the booster transformer or related power supply equipment fails, it will directly affect the power output of the corresponding power generation unit. Utility Model Content

[0003] To address the shortcomings of existing technologies, this utility model provides a double-split 66kV offshore photovoltaic system, which can solve the problem of uneconomical large-scale 66kV offshore photovoltaic projects in the prior art. The double-split transformer in the system provided by this application has one high-voltage winding and two low-voltage windings. The low-voltage winding is split into two parts, which solves the problem of unreliability of power supply using a single branch of double windings in the prior art.

[0004] The present invention adopts the following technical solution.

[0005] A dual-split 66kV offshore photovoltaic system includes a high-voltage chamber, a transformer chamber, and a low-voltage chamber. The high-voltage chamber is connected to one end of the transformer chamber, and the other end of the transformer chamber is connected to the low-voltage chamber.

[0006] The transformer room includes a double-split transformer, copper busbars, and cables. The double-split transformer is connected to the first and second low-voltage switchgear in the low-voltage room via copper busbars, and to the V-type gas-insulated switchgear in the high-voltage room via cables.

[0007] Furthermore, the high-pressure chamber also includes two C-type gas-filled cabinets, each of which includes a first three-position switch and a first live indicator; the V-type gas-filled cabinet includes a second three-position switch and a second live indicator.

[0008] Each incoming submarine cable is connected to one end of the first three-position switch in the C-type gas-insulated switchgear. The other end of the first three-position switch is connected to one end of the second three-position switch. The other end of the second three-position switch is connected to the high-voltage side of the transformer. One end of the first live indicator is connected to the first three-position switch, and the other end is grounded. One end of the second live indicator is connected to the second three-position switch, and the other end is grounded.

[0009] Furthermore, the V-shaped gas-filled switchgear also includes a first current transformer. The first current transformer is fixed in a through-core manner on the line between the second and third position switches and the high-voltage winding of the transformer. One end of the first current transformer is connected to the measurement and control protection device on the second low-voltage switchgear, and the other end is grounded.

[0010] Furthermore, the number of the double-split transformer is one, which includes one high-voltage winding and two low-voltage windings. The high-voltage winding is connected to the V-shaped gas-filled switchgear in the high-voltage compartment, and the low-voltage winding is connected to the two low-voltage switchgear in the low-voltage compartment.

[0011] Furthermore, each low-voltage switchgear includes a frame circuit breaker, a first fuse, and a first molded case circuit breaker. One end of the frame circuit breaker is connected to the low-voltage winding of the double-split transformer, and the other end of the frame circuit breaker is connected to the low-voltage side busbar. One end of the first molded case circuit breaker is connected to the low-voltage side busbar, and the other end is connected to the 16-channel inverter. One end of the first fuse is connected to the low-voltage side busbar, and the other end is connected to the PLC.

[0012] Furthermore, each low-voltage switchgear also includes a second current transformer, a second fuse, and a surge protector. The second current transformer is fixed to the low-voltage side busbar using a through-core type, and one end of the second current transformer is connected to the measurement and control protection device on the instrument door of the upper compartment of the low-voltage switchgear, while the other end is grounded. One end of the surge protector is grounded, and the other end of the surge protector is connected to one end of the second fuse, while the other end of the second fuse is connected to the low-voltage side busbar.

[0013] Furthermore, a control transformer is configured on the side of the second low-voltage switchgear. One end of the control transformer is connected to the low-voltage winding of the double-split transformer, and the other end is connected to one end of the main micro-circuit breaker. The other end of the main micro-circuit breaker is connected to several components through a second molded case circuit breaker. The other end of the main micro-circuit breaker is also connected to one end of the UPS through the second molded case circuit breaker. The other end of the UPS is connected to several loads through a third molded case circuit breaker.

[0014] Furthermore, the control transformer is used to convert 800V voltage to 400V.

[0015] The beneficial effects of this utility model are as follows, compared with the prior art:

[0016] 1. The double-split 66kV offshore photovoltaic system provided by this utility model can effectively limit the short-circuit current on the low-voltage side, thus allowing the use of lightweight switchgear and saving investment. During normal operation, the through-impedance of the double-split transformer is the same as that of a regular transformer. When a short circuit occurs at one end of the low-voltage side, the short-circuit current is smaller due to the larger split impedance.

[0017] 2. When a short circuit occurs on one busbar, the dual-split 66kV offshore photovoltaic system provided by this utility model can not only effectively limit the short circuit current, but also keep the voltage on the other busbar at a certain level, so as not to affect the operation of the equipment on the other busbar. Attached Figure Description

[0018] Figure 1 This is a circuit diagram of a dual-split 66kV offshore photovoltaic system provided by this utility model;

[0019] Figure 2 This is a schematic diagram of the high-voltage chamber circuit provided by this utility model;

[0020] Figure 3 This is a schematic diagram of the low-pressure chamber circuit provided by this utility model. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. The embodiments described in this application are merely some embodiments of this utility model, and not all embodiments. Based on the spirit of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0022] like Figure 1-3 The present invention provides a dual-split 66kV offshore photovoltaic system, including a high-voltage chamber 1, a transformer chamber 2 and a low-voltage chamber 3. The high-voltage chamber 1 is connected to one end of the transformer chamber 2, and the other end of the transformer chamber 2 is connected to the low-voltage chamber 3.

[0023] High-voltage compartment 1 includes two C-type gas-insulated switchgear and two V-type gas-insulated switchgear. Each C-type gas-insulated switchgear includes a first three-position switch 101 and a first live indicator DV1. The V-type gas-insulated switchgear includes a second three-position switch 102 and a second live indicator DV2. The two C-type gas-insulated switchgears are connected to two incoming submarine cables. Each incoming submarine cable is connected to one end of the first three-position switch 101 in the C-type gas-insulated switchgear. The other end of the first three-position switch 101 is connected to one end of the second three-position switch 102. The other end of the second three-position switch 102 is connected to the high-voltage side of the transformer. One end of the first live indicator DV1 is connected to the first three-position switch 101, and the other end is grounded. One end of the second live indicator DV2 is connected to the second three-position switch 102, and the other end is grounded. The first three-position switch 101 includes a first disconnecting switch QS1 and a first grounding switch DES1. The second three-position switch 102 includes a circuit breaker CB, a second disconnecting switch QS2, and a second grounding switch DES2.

[0024] The V-type gas-filled switchgear also includes a first current transformer TA1. The first current transformer TA1 is fixed in a through-core manner on the line between the second three-position switch 102 and the high-voltage winding of the transformer. One end of the first current transformer TA1 is connected to the measurement and control protection device on the second low-voltage switchgear, and the other end is grounded.

[0025] Transformer compartment 2 includes a double-split transformer, copper busbars, and cables. Transformer compartment 2 is connected to the two low-voltage switchgear in low-voltage compartment 3 via copper busbars, and to the V-type gas-insulated switchgear in high-voltage compartment 1 via cables. There is one double-split transformer, consisting of one high-voltage winding and two low-voltage windings. The voltage rating of this double-split transformer is 66kV±2*2.5% / 0.8-0.8kV. The high-voltage winding is connected to the V-type gas-insulated switchgear in high-voltage compartment 1, and the low-voltage winding is connected to the two low-voltage switchgear in low-voltage compartment 3. Transformer oil flows through two oil pipes (one inlet and one outlet), is cooled by an external air cooler, and then flows back into the double-split transformer.

[0026] Low-voltage compartment 3 includes two low-voltage switchgear, one control transformer, and one industrial air conditioner. The two low-voltage switchgear are designated as the first low-voltage switchgear and the second low-voltage switchgear. Each low-voltage switchgear includes a frame circuit breaker QF1, a first fuse FU1, and a first molded case circuit breaker MCCB1. One end of the frame circuit breaker QF1 is connected to the low-voltage winding of the double-split transformer, and the other end of the frame circuit breaker QF1 is connected to the low-voltage side busbar. One end of the first molded case circuit breaker MCCB1 is connected to the low-voltage side busbar, and the other end is connected to the 16-channel inverter INV. One end of the first fuse FU1 is connected to the low-voltage side busbar, and the other end is connected to the PLC.

[0027] Each low-voltage switchgear also includes a second current transformer TA2, a second fuse FU2, and a surge protector SPD. The second current transformer TA2 is fixed to the low-voltage side busbar using a through-core type, and one end of the second current transformer TA2 is connected to the measurement and control protection device on the instrument door of the upper compartment of the low-voltage switchgear, while the other end is grounded. One end of the surge protector SPD is grounded, and the other end of the surge protector SPD is connected to one end of the second fuse FU2. The other end of the second fuse FU2 is connected to the low-voltage side busbar.

[0028] A control transformer TC is located on the side of the second low-voltage switchgear. One end of the control transformer TC is connected to the low-voltage winding, and the other end is connected to one end of the main miniature circuit breaker QF2. The other end of the main miniature circuit breaker QF2 is connected to several high-power components through the second molded case circuit breaker MCCB2. The other end of the main miniature circuit breaker QF2 is also connected to one end of the UPS through the second molded case circuit breaker MCCB2. The other end of the UPS is connected to several low-power important loads through the third molded case circuit breaker MCCB3. The control transformer TC is used to transform the 800V voltage to 400V.

[0029] Each low-voltage switchgear is divided into upper and lower compartments. The upper compartment of the first low-voltage switchgear houses a frame circuit breaker QF1, while the lower compartment houses the low-voltage main busbar, the first molded case circuit breaker MCCB1, the second current transformer TA2, the first fuse FU1, the second fuse FU2, and surge protectors SPD, among other electrical components. The upper compartment of the second low-voltage switchgear houses the frame circuit breaker QF1, low-voltage terminal blocks, several second molded case circuit breakers MCCB2, several third molded case circuit breakers MCCB3, and secondary conductors. The lower compartment of the second low-voltage switchgear houses the low-voltage main busbar, the first molded case circuit breaker MCCB1, the second current transformer TA2, the first fuse FU1, the second fuse FU2, and surge protectors SPD, among other electrical components. The instrument door of the upper compartment is equipped with a measurement and control protection device, a voltmeter, an ammeter, a remote-to-local transfer switch, and a closing / opening button. Both ends of the measurement and control protection device are connected to the measurement and control molded case circuit breaker connected to the UPS. One end of the voltmeter is connected to the control transformer TC, and the other end is connected to the measurement and control protection device. One end of the ammeter is connected to the second current transformer TA2, and the other end is connected to the measurement and control protection device. One end of the remote-to-local transfer switch is connected to the third molded case circuit breaker MCCB3, and the other end is connected to the measurement and control protection device and one end of the closing / opening button. The other end of the closing / opening button is connected to the frame circuit breaker QF1.

[0030] The industrial air conditioner is connected to the main miniature circuit breaker QF2 via the second molded case circuit breaker MCCB2, and is installed on the side door panel of the low-pressure chamber 3 to cool, heat and dehumidify the low-pressure chamber 3.

[0031] In this embodiment, the live display includes a capacitor and a light-emitting device, and the current transformer includes a measuring current transformer and a protective current transformer.

[0032] The dual-split 66kV offshore photovoltaic system also includes an environmental control system, which consists of two reversible fans symmetrically installed on the side of the transformer compartment 2 enclosure. One fan is installed below to allow cold air in, and the other is installed above to exhaust hot air, thus cooling the transformer compartment 2. Each of the high-voltage compartment 1, low-voltage compartment 3, and transformer compartment 2 is equipped with a smoke detector for fire early warning, and the smoke detection signal is uploaded to the monitoring and protection device on the instrument door of the low-voltage cabinet. Each of the high-voltage compartment 1, low-voltage compartment 3, and transformer compartment 2 is equipped with a lighting lamp above the door panel, which illuminates when the compartment door is opened.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of this utility model. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this utility model should be covered within the protection scope of the claims of this utility model.

Claims

1. A dual-split 66kV offshore photovoltaic system comprising a high-voltage chamber, a transformer chamber and a low-voltage chamber, characterized in that: the high-voltage chamber is connected to one end of the transformer chamber, and the other end of the transformer chamber is connected to the low-voltage chamber; the transformer chamber comprises a dual-split transformer, a copper bar and a cable, the dual-split transformer is connected to a first low-voltage cabinet and a second low-voltage cabinet in the low-voltage chamber through the copper bar, and the dual-split transformer is connected to a V-shaped gas-filled cabinet in the high-voltage chamber through the cable. 2.The dual-split 66kV offshore photovoltaic system according to claim 1, characterized in that: the high-voltage chamber further comprises two C-shaped gas-filled cabinets, each C-shaped gas-filled cabinet comprises a first three-position switch and a first live display, and the V-shaped gas-filled cabinet comprises a second three-position switch and a second live display; each incoming line cable is connected to one end of the first three-position switch in the C-shaped gas-filled cabinet, the other end of the first three-position switch is connected to one end of the second three-position switch, the other end of the second three-position switch is connected to the high-voltage side of the transformer, one end of the first live display is connected to the first three-position switch, and the other end is grounded; one end of the second live display is connected to the second three-position switch, and the other end is grounded. 3.The dual-split 66kV offshore photovoltaic system according to claim 2, characterized in that: the V-shaped gas-filled cabinet further comprises a first current transformer, the first current transformer is fixed on the line between the second three-position switch and the high-voltage winding of the transformer in a core-piercing manner, one end of the first current transformer is connected to a measurement and control protection device on the second low-voltage cabinet, and the other end is grounded. 4.The dual-split 66kV offshore photovoltaic system according to claim 1, characterized in that: the number of dual-split transformers is one, the dual-split transformer comprises one high-voltage winding and two low-voltage windings, the high-voltage winding is connected to the V-shaped gas-filled cabinet in the high-voltage chamber, and the low-voltage windings are connected to the two low-voltage cabinets in the low-voltage chamber. 5.The dual-split 66kV offshore photovoltaic system according to claim 4, characterized in that: each low-voltage cabinet comprises a frame circuit breaker, a first fuse and a first molded case circuit breaker, one end of the frame circuit breaker is connected to the low-voltage winding of the dual-split transformer, the other end of the frame circuit breaker is connected to a low-voltage side busbar, one end of the first molded case circuit breaker is connected to the low-voltage side busbar, and the other end is connected to a 16-way inverter, one end of the first fuse is connected to the low-voltage side busbar, and the other end is connected to a PLC. 6.The dual-split 66kV offshore photovoltaic system according to claim 5, characterized in that: each low-voltage cabinet further comprises a second current transformer, a second fuse and a surge protector, the second current transformer is fixed on the low-voltage side busbar in a core-piercing manner, one end of the second current transformer is connected to a measurement and control protection device on a compartment instrument door of the low-voltage cabinet, and the other end is grounded; one end of the surge protector is grounded, the other end of the surge protector is connected to one end of the second fuse, and the other end of the second fuse is connected to the low-voltage side busbar. 7.The dual-split 66kV offshore photovoltaic system according to claim 6, characterized in that: The side of the second low-voltage cabinet is configured with a control transformer, one end of the control transformer is connected with the low-voltage winding of the double-split transformer, the other end is connected with one end of a total micro switch, the other end of the total micro switch is connected with a plurality of components through a second molded case circuit breaker, and the other end of the total micro switch is also connected with one end of a UPS through the second molded case circuit breaker, and the other end of the UPS is connected with a plurality of loads through a third molded case circuit breaker.

8. The dual-split 66 kV offshore photovoltaic system according to claim 7, characterized in that: The control transformer transforms 800V voltage into 400V.