Variable speed tidal generator set in combination with offshore wind

Abstract

The application discloses a variable-speed tidal generator set combined with offshore wind power, which comprises a plurality of tidal generator sets arranged below the sea surface, each tidal generator set being connected with an offshore wind generator set arranged above the sea surface through a tower drum; the tower drum adopts a single-pile structure, and comprises an outer tower drum and an inner tower drum; the inner tower drum is a rigid solid structure and is used for supporting the offshore wind generator set and the tidal generator set; the offshore wind generator set and the tidal generator set are respectively connected with wind generator set blades and tidal generator set blades. Compared with common offshore wind power foundation types, the foundation pile arrangement type combined with the tidal generator set has a better application prospect for newly-built offshore wind farms.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of offshore wind power and tidal power combination, and particularly relates to a variable-speed tidal generator set combined with offshore wind power. BACKGROUND

[0002] There are rich renewable energy resources in the ocean which have not been developed. Offshore wind power resources have great potential, and meanwhile, the coastline contains extremely rich tidal energy resources.

[0003] However, whether developing offshore wind power alone or developing tidal power alone will face huge construction costs. In particular, tidal power is affected by natural conditions, has volatility and intermittency, resulting in low utilization rate of tidal energy; the construction cost of ordinary tidal energy power generation projects is high, which indirectly raises the power generation cost, and the demand for capital investment in later maintenance and depreciation is also large, so the high cost problem of tidal power is a key problem faced by the industry development. SUMMARY

[0004] The purpose of the present application is to solve the problems in the background art, and to provide a variable-speed tidal generator set combined with offshore wind power.

[0005] The technical scheme adopted by the present application is: a variable-speed tidal generator set combined with offshore wind power, comprising a plurality of tidal generator sets arranged below the sea surface, each tidal generator set being connected to an offshore wind turbine arranged above the sea surface through a tower drum; the tower drum adopts a single pile structure, and comprises an outer tower drum and an inner tower drum, the inner tower drum being a rigid solid structure for supporting the offshore wind turbine and the tidal generator set; the offshore wind turbine and the tidal generator set are respectively connected to wind turbine blades and tidal generator set blades.

[0006] Further preferably, a gap is provided between the outer tower drum and the inner tower drum, and a sliding roller for driving the tidal generator set to rotate is arranged in the gap.

[0007] Further preferably, the sliding roller is driven by a hydraulic yaw mechanism.

[0008] In the above scheme, the sliding roller between the inner tower drum and the outer tower drum functions to rotate the tidal generator set below the sea surface by 360 degrees, and the power comes from the hydraulic yaw mechanism shared with the offshore wind turbine.

[0009] Further preferably, the tidal generator set and the offshore wind turbine are connected through a common three-circle box transformer substation, and then connected to a centralized substation through a 35kV power collection line.

[0010] In a further preferred configuration, the electrical equipment and cables of the offshore wind turbine and the tidal generator are all arranged within the gap between the outer tower and the inner tower.

[0011] In a further preferred configuration, the centralized booster station is connected to the power grid.

[0012] In a further preferred configuration, the tidal generator set adopts a variable-speed doubly-fed generator, and through a back-to-back converter, dynamically adjusts the rotor speed and the current frequency of the rotor winding to achieve variable-speed constant-frequency power generation of the stator winding of the unit.

[0013] The beneficial effects of this invention are: for newly constructed offshore wind farms, compared with ordinary offshore wind power foundation types, the foundation pile arrangement type combined with tidal generator units has better application prospects, which can realize the development of two marine renewable resources with a single investment, achieve energy complementarity between offshore wind power and tidal energy, and make full use of electrical equipment and transmission lines. Attached Figure Description

[0014] Fig. 1 This is a schematic diagram of a variable-speed tidal generator set combined with offshore wind power.

[0015] Fig. 2 This is a cross-sectional view of the tower.

[0016] Fig. 3 This is the electrical wiring diagram for a variable-speed tidal generator set integrated with offshore wind power.

[0017] In the diagram, 1-offshore wind turbine (101-wind turbine blade), 2-tidal turbine (201-tidal turbine blade), 3-tower (301-outer tower, 302-inner tower, 303-sliding roller), 4-centralized substation, 5-power grid; A-three-ring transformer substation; B-converter. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments to facilitate a clear understanding of the present invention, but these descriptions do not constitute a limitation on the present invention.

[0019] like Figs. 1-3 As shown, the present invention includes multiple tidal generator sets 2 arranged below the sea surface, each of the tidal generator sets 2 being connected to an offshore wind turbine set 1 arranged above the sea surface via a tower 3; the tower 3 adopts a monopile structure, the tower 3 including an outer tower 301 and an inner tower 302, the inner tower 302 being a rigid solid structure used to support the offshore wind turbine set 1 and the tidal generator set 2; the offshore wind turbine set 1 and the tidal generator set 2 are respectively connected to the wind turbine blade 101 and the tidal turbine blade 201.

[0020] A gap is provided between the outer tower cylinder 301 and the inner tower cylinder 302, and a sliding roller 303 for driving the tidal power generator set 2 to rotate is arranged in the gap.

[0021] The sliding roller 303 is driven by a hydraulic yaw mechanism.

[0022] The tidal power generator set 2 and the offshore wind power generator set 1 are connected to the centralized booster station 4 through a common three-circle box transformer A and a 35kV power collection line.

[0023] The electrical equipment and electrical cable of the offshore wind power generator set 1 and the tidal power generator set 2 are arranged in the gap between the outer tower cylinder 301 and the inner tower cylinder 302.

[0024] The centralized booster station 4 is connected to the power grid 5.

[0025] The tidal power generator set 2 adopts a variable-speed double-fed generator, and through a back-to-back converter B, the rotor speed and the rotor winding current frequency are dynamically adjusted to realize variable-speed constant-frequency power generation of the stator winding of the generator set.

[0026] The function of the hydraulic yaw mechanism of the offshore wind power generator set 1 is to track the change of wind direction, drive the nacelle of the offshore wind power generator set 1 to rotate around the central axis of the tower cylinder 3, and make the wind wheel always be in the windward position. The tidal power generator set 2 also needs to rotate the nacelle direction to track the change of tidal energy. The sliding roller 303 is arranged between the inner tower cylinder 302 and the outer tower cylinder 301 of the offshore wind power generator set 1, and the tidal power generator set 2 is rotated through the power of the shared hydraulic yaw mechanism.

[0027] Determining the capacity of the tidal power generator set 2 is a prerequisite for determining the volume of the inner and outer tower cylinders of the offshore wind power generator set 1. By estimating the developable tidal energy of a piece of sea area, the specification of the tidal power generator set 2 to be installed on the single-pile offshore wind power foundation can be estimated. The tidal energy P0 (unit: J) is estimated as follows:

[0028]

[0029] In the formula, ρ is the density of seawater (the density of seawater is 1025 kg / m 3 ), A is the force receiving area (unit: m 2 ) of the tidal power generator set blade 201, V tide is the calculated flow velocity of the tidal current. However, due to the capacity loss, the tidal power generator set 2 can only use part of the energy, that is,

[0030]

[0031] In the formula, C pis the power coefficient (estimated value 0.35-0.5). The specific calculation formula of the calculation flow rate of the tidal current is:

[0032]

[0033] In the formula, V st and V nt is the large and small tidal current speed in the sea area, C is the tidal coefficient of the sea area, 95 and 45 are the large and small tidal coefficients, respectively.

[0034] The principle of the tidal generator set 2 of the application is to use the generator to extract the kinetic energy contained in the sea current, so it needs to be installed in the high-energy site of tidal energy. However, the ocean is affected by turbulence and strong waves, and the flow of the tidal current changes greatly. In order to adapt to the volatility of tidal energy, for the selection of the tidal generator set 2, in order to realize the high-efficiency operation of the tidal generator set 2 under the condition of large sea water flow rate variation, the tidal power generation adopts a variable speed unit. Compared with the fixed speed unit, the advantage of the variable speed unit is very important for the high-efficiency power generation of the generator set in the unstable flow rate. In terms of control of the generator set, the variable speed tidal generator set realizes the regulation of the rotor speed and the current frequency of the rotor winding through the back-to-back converter B, and realizes the variable speed constant frequency power generation of the stator winding of the unit.

[0035] In terms of electrical connection, in order to reduce the construction cost, the electrical equipment of the offshore wind generator set 1 and the tidal generator set 2 is shared as much as possible. First of all, the outlet voltage of the offshore wind generator set 1 and the tidal generator set 2 needs to be boosted locally, and a three-circle box transformer A shared by the two generator sets can be set; secondly, after boosting, the two can share a 35kV power collection line and a centralized booster station 4 to be connected with the power grid 5.

[0036] Compared with the ordinary offshore wind power foundation type, the foundation pile arrangement type combined with the tidal generator set 2 has better application prospect for the newly built offshore wind farm, which has the advantages of realizing the development of two kinds of marine renewable resources with single investment, realizing energy complementation of offshore wind power and tidal energy, and fully utilizing electrical equipment and transmission lines. At the same time, the novel type proposed by the application has certain significance for reducing the development cost of tidal energy and improving the popularization rate of tidal power generation.

[0037] The contents not described in detail in the specification belong to the prior art known to those skilled in the art.

Claims

1. A variable speed tidal generator set in combination with an offshore wind turbine, characterised in that: The application relates to a tidal power generation system, which comprises a plurality of tidal power generation units (2) arranged below the sea surface, each tidal power generation unit (2) being connected with a sea wind power generation unit (1) arranged above the sea surface through a tower drum (3); the tower drum (3) adopts a single-pile structure, and comprises an outer tower drum (301) and an inner tower drum (302); the inner tower drum (302) is a rigid solid structure for supporting the sea wind power generation unit (1) and the tidal power generation unit (2); the sea wind power generation unit (1) and the tidal power generation unit (2) are respectively connected with wind power generation unit blades (101) and tidal power generation unit blades (201); a gap is arranged between the outer tower drum (301) and the inner tower drum (302), and a sliding roller (303) for driving the tidal power generation unit (2) to rotate is arranged in the gap; the sliding roller (303) is driven by a hydraulic yaw mechanism; the hydraulic yaw mechanism also drives the cabin of the sea wind power generation unit (1) to rotate around the central axis of the tower drum (3), so that the wind wheel is always in a wind-attacking position; the tidal power generation unit (2) and the sea wind power generation unit (1) are boosted by a common three-circle box transformer (A), and then connected with a centralized booster station (4) through a 35kV power collection line; the electrical equipment and the electrical cable of the sea wind power generation unit (1) and the tidal power generation unit (2) are arranged in the gap between the outer tower drum (301) and the inner tower drum (302); the centralized booster station (4) is connected with a power grid (5); the tidal power generation unit (2) adopts a variable-speed double-fed generator, and the rotor rotating speed and the rotor winding current frequency are dynamically adjusted through a back-to-back converter (B), so that the variable-speed constant-frequency power generation of the stator winding of the unit is realized. ​ ​ ​ ​ ​ ​

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