DK177980B1

DK177980B1 - Wind turbine radio communication system

Info

Publication number: DK177980B1
Application number: DK201470015A
Authority: DK
Inventors: Per Holgersen; Bjarke Thagaard Ovesen
Original assignee: Semco Maritime As
Priority date: 2014-01-14
Filing date: 2014-01-14
Publication date: 2015-02-09

Abstract

The invention relates to a wind turbine radio communication system. The communication system is a digital two-way radio system, and comprises an outside antenna for being mounted outside of a wind turbine structure. The system further comprises an inside tower antenna for being mounted inside the wind turbine tower. Finally, the system comprises a digital two-way radio system repeater for being in communication with the outside antenna and with the inside tower antenna, the repeater being configured for relaying radio signals received with the outside antenna with the inside tower antenna, and vice versa. The invention further relates to a wind turbine comprising the radio communications system.

Description

Wind turbine radio communication system FIELD OF THE INVENTIONWind turbine radio communication system FIELD OF THE INVENTION

The present invention relates to a wind turbine radio communication system. More particularly, the invention relates to a system for providing radio communication coverage within a wind turbine tower and/or transition piece (TP).The present invention relates to a wind turbine radio communication system. More particularly, the invention relates to a system for providing radio communication coverage within a wind turbine tower and / or transition piece (TP).

BACKGROUND OF THE INVENTIONBACKGROUND OF THE INVENTION

As wind turbines installed tend to become increasingly large, and to be deployed in even more remote locations and harsh environments, issues of personnel security has an increased focus in the industry. This is especially the case for offshore wind turbines, where even minor accidents may have particularly severe consequences.As wind turbines installed tend to become increasingly large, and to be deployed in even more remote locations and harsh environments, issues of personnel security have an increased focus in the industry. This is especially the case for offshore wind turbines, where even minor accidents may have particularly severe consequences.

One safety problem relating to wind turbines is that radio coverage within the wind turbine tower or transition piece (TP) onto which the tower is mounted, is generally very poor. This is caused by the Faraday's cage effect of the steel towers in common use. US 2002/0028655 A1 discloses a repeater system for wireless communications, particularly for cellular phones. The repeater system includes a repeater coupled to an inside antenna system and to an outside antenna system, wherein the inside antenna system is inside a structure in the form of an edifice or a vessel. The document is silent about use in wind turbine towers and/or transition pieces.One safety issue related to wind turbines is that radio coverage within the wind turbine tower or transition piece (TP) onto which the tower is mounted is generally very poor. This is caused by the Faraday's cage effect of the steel towers in common use. US 2002/0028655 A1 discloses a repeater system for wireless communications, particularly for cellular phones. The repeater system includes a repeater coupled to an inside antenna system and to an outside antenna system, where the inside antenna system is inside a structure in the form of an edifice or a vessel. The document is silent about use in wind turbine towers and / or transition pieces.

Hence, an improved wind turbine personnel safety system would be advantageous, and in particular a more efficient and/or reliable radio communications system would be advantageous.Therefore, an improved wind turbine personnel safety system would be advantageous, and in particular a more efficient and / or reliable radio communications system would be advantageous.

OBJECT OF THE INVENTIONOBJECT OF THE INVENTION

It is a further object of the present invention to provide an alternative to the prior art.It is a further object of the present invention to provide an alternative to the prior art.

In particular, it may be seen as an object of the present invention to provide a wind turbine radio communication system that solves the above mentioned problems of the prior art with obtaining an adequate radio coverage within a wind turbine tower and/or transition piece.In particular, it may be seen as an object of the present invention to provide a wind turbine radio communication system that solves the above mentioned problems of the prior art with obtaining adequate radio coverage within a wind turbine tower and / or transition piece.

SUMMARY OF THE INVENTIONSUMMARY OF THE INVENTION

Thus, the above described object and several other objects are intended to be obtained in a first aspect of the invention by providing a wind turbine radio communications system. The communication system is a digital two-way radio system, and comprises an outside antenna for being mounted outside of a wind turbine structure. The system further comprises an inside tower antenna for being mounted inside the wind turbine tower. Finally, the system comprises a digital two-way radio system repeater for being in communication with the outside antenna and with the inside tower antenna, the repeater being configured for relaying radio signals received with the outside antenna with the inside tower antenna, and vice versa. In this way, the problem of obtaining radio coverage within the wind turbine tower may be alleviated, thereby greatly improving security for e.g. technicians working within the wind turbine. More specifically, the communication system acts to bi-directionally relay transmission between the inside and outside of the wind turbine, and thereby circumventing the "Faraday Cage"-effect of the tower.Thus, the object described above and several other objects are intended to be obtained in a first aspect of the invention by providing a wind turbine radio communications system. The communication system is a digital two-way radio system, and comprises an outside antenna for being mounted outside of a wind turbine structure. The system further comprises an inside tower antenna for being mounted inside the wind turbine tower. Finally, the system comprises a digital two-way radio system repeater for being in communication with the outside antenna and with the inside tower antenna, the repeater being configured for relaying radio signals received with the outside antenna with the inside tower antenna, and vice versa . In this way, the problem of obtaining radio coverage within the wind turbine tower may be alleviated, thereby greatly improving security for e.g. technicians working within the wind turbine. More specifically, the communication system acts to bi-directionally relay transmission between the inside and outside of the wind turbine, thereby circumventing the "Faraday Cage" effect of the tower.

In an embodiment of the inventive communication system, the digital two-way radio system is a terrestrial trunked radio (TETRA) system. In this way, the system may provide "seam-less" radio coverage for personnel entering the wind turbine with a suitable radio terminal. Thus, no manual intervention is required to adjust the radio terminal when moving from outside to inside the tower, or vice versa.In an embodiment of the inventive communication system, the digital two-way radio system is a terrestrial trunked radio (TETRA) system. In this way, the system may provide "seam-less" radio coverage for personnel entering the wind turbine with a suitable radio terminal. Thus, no manual intervention is required to adjust the radio terminal when moving from outside to inside the tower, or vice versa.

In an alternative embodiment of the communication system, the digital two-way radio system is a Digital Mobile Radio (DMR) system.In an alternative embodiment of the communication system, the digital two-way radio system is a Digital Mobile Radio (DMR) system.

In an embodiment of the inventive communication system, the outside antenna is an omni-directional antenna. In this way, a particularly versatile communication system may be achieved in that a communication party located outside the tower may obtain a good radio connection to the communication system, irrespective of a position of that communication party, relative to the wind turbine.In an embodiment of the inventive communication system, the outside antenna is an omni-directional antenna. In this way, a particularly versatile communication system may be achieved in that a communication party located outside the tower may obtain a good radio connection to the communication system, irrespective of a position of that communication party, relative to the wind turbine.

In an alternative embodiment, the outside antenna is a directional antenna. In this way, the directional outside antenna may enable an uplink to a distal radio transceiver with improved signal strength and/or transmission range.In an alternative embodiment, the outside antenna is a directional antenna. In this way, the directional outside antenna may enable an uplink to a distal radio transceiver with improved signal strength and / or transmission range.

In an embodiment of the inventive communication system, the inside tower antenna is a directional, circularly polarized antenna. In this way, an improved transmission range is obtained within the wind turbine tower, i.e. so as to provide radio coverage throughout the height of the tower. For instance, if the inside tower antenna is mounted at the bottom of the tower, use of a directional and circularly polarized antenna enables radio coverage toward the top of the tower.In an embodiment of the inventive communication system, the inside tower antenna is a directional, circularly polarized antenna. In this way, an improved transmission range is obtained within the wind turbine tower, i.e. so as to provide radio coverage throughout the height of the tower. For instance, if the inside tower antenna is mounted at the bottom of the tower, use of a directional and circularly polarized antenna enables radio coverage towards the top of the tower.

In an embodiment of the inventive communication system, the inside tower antenna is a flat-panel antenna. Thus, a particularly space-efficient inside tower antenna may be achieved.In an embodiment of the inventive communication system, the inside tower antenna is a flat-panel antenna. Thus, a particularly space-efficient inside tower antenna may be achieved.

In an embodiment of the inventive communication system, the system further comprises an inside transition piece (TP) antenna for being mounted inside a wind turbine transition piece, wherein the repeater is also adapted for being in communication with the inside TP antenna, the repeater further being configured for relaying radio signals received with the outside antenna with the inside TP antenna, and vice versa. In this way, the communication system may also provide radio coverage within the transition piece of the wind turbine, i.e. below the wind turbine tower.In an embodiment of the inventive communication system, the system further comprises an inside transition piece (TP) antenna for being mounted inside a wind turbine transition piece, the repeater is also adapted for being in communication with the inside TP antenna, the repeater further being configured for relaying radio signals received with the outside antenna with the inside TP antenna, and vice versa. In this way, the communication system may also provide radio coverage within the transition piece of the wind turbine, i.e. below the wind turbine tower.

In an embodiment of the inventive communication system, the inside tower antenna and inside TP antenna are nominally identical. In this way, a particularly cost-efficient and simplified system may be achieved that uses fewer parts. Thus costs related to keeping stock or inventory may be reduced, by allowing interchanging antennas e.g. in case of malfunction or maintenance.In an embodiment of the inventive communication system, the inside tower antenna and inside TP antenna are nominally identical. In this way, a particularly cost-efficient and simplified system may be achieved that uses fewer parts. Thus costs related to keeping stock or inventory may be reduced, by allowing interchanging antennas e.g. in case of malfunction or maintenance.

In an embodiment of the inventive communication system, the inside TP antenna is a directional, circularly polarized antenna. In this way, an improved transmission range is obtained within the wind turbine transition piece, i.e. so as to provide radio coverage substantially throughout TP from the foundation to the tower. For instance, if the inside TP antenna is mounted at the top of the TP, use of a directional and circularly polarized antenna enables radio coverage toward the bottom of the TP. Alternatively, the inside TP antenna may be mounted at the bottom of the tower in a vicinity to the top of the TP.In an embodiment of the inventive communication system, the inside TP antenna is a directional, circularly polarized antenna. In this way, an improved transmission range is obtained within the wind turbine transition piece, i.e. so as to provide radio coverage substantially throughout TP from the foundation to the tower. For instance, if the inside TP antenna is mounted at the top of the TP, use of a directional and circularly polarized antenna enables radio coverage towards the bottom of the TP. Alternatively, the inside TP antenna may be mounted at the bottom of the tower in the vicinity of the top of the TP.

In an embodiment of the inventive communication system, the inside TP antenna is a flat-panel antenna. Thus, a particularly space-efficient inside TP antenna may be achieved.In an embodiment of the inventive communication system, the inside TP antenna is a flat-panel antenna. Thus, a particularly space-efficient inside TP antenna may be achieved.

In an embodiment of the inventive communication system, the repeater is a trunk-mode-operation/trunk-mode-operation (TMO/TMO) repeater. In this way, the communication system may be seamlessly integrated in existing two-way digital radio systems, such as TETRA. Thus, personnel entering or leaving the wind turbine need not adjust or change settings on their radio terminal.In an embodiment of the inventive communication system, the repeater is a trunk-mode operation / trunk-mode operation (TMO / TMO) repeater. In this way, the communication system may be seamlessly integrated into existing two-way digital radio systems, such as TETRA. Thus, personnel entering or leaving the wind turbine do not need to adjust or change settings on their radio terminal.

In an embodiment of the inventive communication system, the repeater is a TETRA repeater, and optionally the outside and/or inside antennas is/are configured for a Rx/Tx- channel spacing of nominally 14.5MHz. By allowing such a nonstandard channel spacing for a TETRA system, operation in certain jurisdictions with difficulty of obtaining a frequency license using the standard spacing of 10MHz is enabled. For instance, it is difficult to obtain a frequency licence in United Kingdom for a spacing of 10MHz, whereas a licence for a spacing of 14.5MHz surprisingly has been found to be obtainable.In an embodiment of the inventive communication system, the repeater is a TETRA repeater, and optionally the outside and / or inside antennas are / are configured for an Rx / Tx channel spacing of nominally 14.5MHz. By allowing such nonstandard channel spacing for a TETRA system, operation in certain jurisdictions with difficulty obtaining a frequency license using the standard 10MHz spacing is enabled. For instance, it is difficult to obtain a frequency license in the United Kingdom for a spacing of 10MHz, whereas a license for a spacing of 14.5MHz has surprisingly been found to be obtainable.

In another embodiment, the repeater and optionally the outside and/or inside antennas is/are configured for a Rx/Tx- channel spacing of nominally 10MHz. Thus, the system is adapted for the standard frequency spacing of a TETRA system.In another embodiment, the repeater and optionally the outside and / or inside antennas are / are configured for a Rx / Tx channel spacing of nominally 10MHz. Thus, the system is adapted for the standard frequency spacing of a TETRA system.

In an embodiment of the inventive communication system, the repeater and optionally the outside and/or inside antennas is/are configured for a Rx/Tx-channel spacing of nominally 7MHz.In an embodiment of the inventive communication system, the repeater and optionally the outside and / or inside antennas are / are configured for a Rx / Tx channel spacing of nominally 7MHz.

In an embodiment of the inventive communication system, the repeater is configured for providing a reduced antenna power output on the inside TP antenna, when compared to the antenna power output of the inside tower antenna. Since the volume of TP is less than the volume of the tower, sufficient radio coverage in the TP may be achieved using less output power. In this way, power efficiency is improved, and the risk of detrimental reflections of the radio waves is reduced.In an embodiment of the inventive communication system, the repeater is configured to provide a reduced antenna power output on the inside TP antenna, when compared to the antenna power output of the inside tower antenna. Since the volume of TP is less than the volume of the tower, sufficient radio coverage in the TP may be achieved using less output power. In this way, power efficiency is improved, and the risk of detrimental reflections of the radio waves is reduced.

In an embodiment of the inventive communication system, the repeater is adapted for transmitting state messages indicating an operational status of the communication system, preferably via a Simple Network Management Protocol (SNMP) module comprised by the repeater. Thus, personnel security is even further improved by monitoring the communication system with regards to operational faults or malfunctions.In an embodiment of the inventive communication system, the repeater is adapted for transmitting state messages indicating an operational status of the communication system, preferably via a Simple Network Management Protocol (SNMP) module comprised by the repeater. Thus, personnel security is even further improved by monitoring the communication system with regards to operational faults or malfunctions.

In one embodiment of the system, the SNMP module is adapted for transmitting data signals over a local area network (LAN) connection.In one embodiment of the system, the SNMP module is adapted for transmitting data signals over a local area network (LAN) connection.

The invention is particularly, but not exclusively, advantageous for obtaining improved radio communication coverage within wind turbine structures, such as the wind turbine tower and transition piece.The invention is particularly, but not exclusively, advantageous for obtaining improved radio communication coverage within wind turbine structures, such as the wind turbine tower and transition piece.

According to a second aspect, the invention is also particularly, but not exclusively, advantageous for obtaining a wind turbine comprising the wind turbine radio communication system according to the first aspect.According to a second aspect, the invention is also particularly, but not exclusively, advantageous for obtaining a wind turbine comprising the wind turbine radio communication system according to the first aspect.

In an embodiment of the wind turbine according to the invention, the wind turbine is an offshore wind turbine.In an embodiment of the wind turbine according to the invention, the wind turbine is an offshore wind turbine.

In an alternative embodiment, the wind turbine is an onshore wind turbine.In an alternative embodiment, the wind turbine is an onshore wind turbine.

In an embodiment of the wind turbine according to the invention, the inside tower antenna is mounted in a bottom part of the wind turbine tower, and oriented to emit in a generally upwards vertical direction.In an embodiment of the wind turbine according to the invention, the inside tower antenna is mounted in a bottom part of the wind turbine tower, and oriented to emit in a generally upward vertical direction.

In an embodiment of the wind turbine according to the invention, the inside TP antenna is mounted in an upper part of the wind turbine transition piece or in a bottom part of the wind turbine tower, and oriented to emit in a generally downwards vertical direction.In an embodiment of the wind turbine according to the invention, the inner TP antenna is mounted in an upper part of the wind turbine transition piece or in a bottom part of the wind turbine tower, and oriented to emit in a generally downward vertical direction.

The first and second aspect of the present invention may each be combined with any of the other aspects. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.The first and second aspects of the present invention may each be combined with any of the other aspects. These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE FIGURESLETTER DESCRIPTION OF THE FIGURES

The wind turbine radio communication system according to the invention will now be described in more detail with regard to the accompanying figures. The figures show one way of implementing the present invention and is not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.The wind turbine radio communication system according to the invention will now be described in more detail with respect to the accompanying figures. The figures show one way of implementing the present invention and are not construed as being limiting to other possible embodiments falling within the scope of the attached claim set.

Figure 1 illustrates a wind turbine comprising the wind turbine communication system according to an embodiment of the invention.Figure 1 illustrates a wind turbine comprising the wind turbine communication system according to an embodiment of the invention.

Figure 2 schematically shows a communication system according to another embodiment of the invention.Figure 2 schematically shows a communication system according to another embodiment of the invention.

DETAILED DESCRIPTION OF AN EMBODIMENTDETAILED DESCRIPTION OF AN EMBODIMENT

Figure la illustrates a wind turbine 1, comprising a wind turbine tower 2, mounted on a transition piece (TP) 3. The wind turbine shown is an off-shore wind turbine, as indicated by the sea surface 4. The wind turbine further comprises a radio communication system 10 as highlighted in Figure lb. In the present embodiment, the communication system is illustrated to be installed towards the bottom of the wind turbine tower 2, although other locations may also be envisioned. The system 10 comprises an outside antenna 12 mounted in a suitable position outside the wind turbine tower 2. The outside antenna 12 is connected via cable to a digital two-way radio system repeater 14. The repeater 14 is here illustrated to be mounted inside the tower 2, but may in other embodiments be mounted outside the tower, e.g. in proximity to or in connection with the outside antenna 12. The repeater 14 is further connected by cable to an inside tower antenna 16, which is arranged to emit primarily in a vertical upwards direction, as indicated by the zigzag line 18. By configuring the repeater 14 to relay digital radio communication received by the outside antenna to the inside tower antenna, improved radio communication coverage may be achieved within the wind turbine tower.Figure la illustrates a wind turbine 1, comprising a wind turbine tower 2, mounted on a transition piece (TP) 3. The wind turbine shown is an off-shore wind turbine, as indicated by the sea surface 4. The wind turbine further comprises a radio communication system 10 as highlighted in Figure lb. In the present embodiment, the communication system is illustrated to be installed towards the bottom of the wind turbine tower 2, although other locations may also be envisioned. The system 10 comprises an outside antenna 12 mounted in a suitable position outside the wind turbine tower 2. The outside antenna 12 is connected via cable to a digital two-way radio system repeater 14. The repeater 14 is illustrated here to be mounted inside the tower 2, but may in other embodiments be mounted outside the tower, eg in proximity to or in connection with the outside antenna 12. The repeater 14 is further connected by cable to an inside tower antenna 16, which is arranged to emit primarily in a vertical upward direction, as indicated by the zigzag line 18. By configuring the repeater 14 to relay digital radio communication received from the outside antenna to the inside tower antenna, improved radio communication coverage may be achieved within the wind turbine tower.

In a preferred embodiment of the communication system according to the invention, the system operates according to the TETRA standard. As such, the outside antenna 12, inside tower antenna 16, and the repeater 14 are all adapted for the specific radio frequencies used. Furthermore, the repeater is preferably configured as a trunk-mode-operation (TMO)/ Trunk-mode-operation (TMO) repeater, i.e. to seamlessly relay the received TETRA signal from the outside into the tower and vice versa. In certain variations of the present system, the repeater 14 is further equipped with an online monitoring system, e.g. connected via a local area network - and configured for transmitting status and/or performance data from the repeater to a remote location. The online monitoring system is preferably a Simple Network Management Protocol (SNMP) module.In a preferred embodiment of the communication system according to the invention, the system operates according to the TETRA standard. As such, the outside antenna 12, inside tower antenna 16, and the repeater 14 are all adapted for the specific radio frequencies used. Furthermore, the repeater is preferably configured as a trunk mode operation (TMO) / Trunk mode operation (TMO) repeater, i.e. to seamlessly relay the received TETRA signal from the outside into the tower and vice versa. In certain variations of the present system, the repeater 14 is further equipped with an online monitoring system, e.g. connected via a local area network - and configured for transmitting status and / or performance data from the repeater to a remote location. The online monitoring system is preferably a Simple Network Management Protocol (SNMP) module.

In another preferred embodiment of the communication system according to the invention, the system operates according to the Digital Mobile Radio (DMR) standard.In another preferred embodiment of the communication system according to the invention, the system operates according to the Digital Mobile Radio (DMR) standard.

The inventors have found that a particularly good radio coverage within the wind turbine tower may be achieved by using an inside tower antenna which is designed to emit circularly polarized radio waves. This polarization has been found to minimize interfering reflections from the tower structure. Such an antenna may preferably be of a flat-panel type, to minimize space consumption within the wind turbine.The inventors have found that particularly good radio coverage within the wind turbine tower may be achieved by using an inside tower antenna which is designed to emit circularly polarized radio waves. This polarization has been found to minimize interfering reflections from the tower structure. Such an antenna may preferably be of a flat-panel type, to minimize space consumption within the wind turbine.

The outside antenna 12 is preferably of an omni-directional type so as to enable radio communication with radio operators outside the wind turbine, regardless of their position in relation to the turbine.The outside antenna 12 is preferably of an omni-directional type so as to enable radio communication with radio operators outside the wind turbine, regardless of their position in relation to the turbine.

Figure 2 shows another embodiment of the communication system according to the invention when mounted in a wind turbine. The embodiment relates to the one shown in Figure lb, for which reason only the differences between the two embodiments are described. In this embodiment, the communication system 10 comprises an inside TP antenna 20 in addition to the inside tower antenna 16. The inside TP antenna 20 is located and oriented to emit primarily in a downwards vertical direction, as indicated by the line 22. Thus, the inside TP antenna 20 provides improved radio communication coverage in the TP - in addition to the coverage in the tower provided by the inside tower antenna 16. In this embodiment, the repeater 14 is adapted to relay outside communication received on the outside antenna 12 onto both the inside tower antenna 16 and the inside TP antenna 20 simultaneously, so as to provide seamless operation throughout the wind turbine structures of both tower and TP. Since the volume of the TP is generally significantly less than the volume of the tower, the transmission output power on the inside TP antenna 20 is preferably reduced compared to the transmission output power on the inside tower antenna. In one embodiment, the output power on the inside TP antenna is -20dB, compared to the output power of the inside tower antenna. However, it is also envisioned that for other configurations of wind turbines, output power reductions of -3dB, -5dB, -lOdB, or -15dB would be suitable to reach adequate power while maintaining a low degree of reflections from the TP structure. The inside TP antenna 20 is preferably of the same or similar type as the inside tower antenna 16, such as a circularly polarized flat-panel antenna.Figure 2 shows another embodiment of the communication system according to the invention when mounted in a wind turbine. The embodiment relates to the one shown in Figure 1b, for which reason only the differences between the two embodiments are described. In this embodiment, the communication system 10 comprises an inside TP antenna 20 in addition to the inside tower antenna 16. The inner TP antenna 20 is located and oriented to emit primarily in a downward vertical direction, as indicated by line 22. Thus, the inside TP antenna 20 provides improved radio communication coverage in the TP - in addition to the coverage in the tower provided by the inside tower antenna 16. In this embodiment, the repeater 14 is adapted to relay outside communication received on the outside antenna 12 onto both the inside tower antenna 16 and the inside TP antenna 20 simultaneously, so as to provide seamless operation throughout the wind turbine structures of both tower and TP. Since the volume of the TP is generally significantly less than the volume of the tower, the transmission output power on the inside TP antenna 20 is preferably reduced compared to the transmission output power on the inside tower antenna. In one embodiment, the output power on the inside TP antenna is -20dB, compared to the output power of the inside tower antenna. However, it is also envisioned that for other configurations of wind turbines, output power reductions of -3dB, -5dB, -lOdB, or -15dB would be suitable to achieve adequate power while maintaining a low degree of reflections from the TP structure. The inside TP antenna 20 is preferably of the same or similar type as the inside tower antenna 16, such as a circularly polarized flat-panel antenna.

Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the presented examples. For instance, even though the system has been described in the context of an off-shore wind turbine, the use in connection with on-shore wind turbines is also envisioned. Furthermore, the system may also be used for wind turbines deployed without a transition piece, without deviation from the scope of the invention. The scope of the present invention is set out by the accompanying claim set. In the context of the claims, the terms "comprising" or "comprises" do not exclude other possible elements or steps. Also, the mentioning of references such as "a" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims, may possibly be advantageously combined, and the mentioning of these features in different claims does not exclude that a combination of features is not possible and advantageous.Although the present invention has been described in connection with the specified embodiments, it should not be construed as being in any way limited to the examples presented. For instance, even though the system has been described in the context of an off-shore wind turbine, its use in connection with on-shore wind turbines is also envisioned. Furthermore, the system may also be used for wind turbines deployed without a transition piece, without deviation from the scope of the invention. The scope of the present invention is set out in the accompanying claim set. In the context of the claims, the terms "comprising" or "comprising" do not exclude other possible elements or steps. Thus, the mention of references such as "an" or "an" etc. should not be construed as excluding a plurality. The use of reference signs in the claims with respect to elements indicated in the figures shall also not be construed as limiting the scope of the invention. Furthermore, individual features mentioned in different claims may be advantageously combined, and the mention of these features in different claims does not exclude that a combination of features is not possible and advantageous.

Claims

A wind turbine radio communication system (10), which communication system is a digital two-way radio system, comprising: - an external antenna (12) for mounting externally to a wind turbine structure (1), - an internal tower antenna (16) for be mounted internally in the wind turbine tower (2), - a digital two-way radio system repeater (14) to communicate with the external antenna and the internal tower antenna, the repeater is configured to transmit radio signals received with the external antenna with the internal tower antenna, and vice versa, characterized in that the system further comprises an internal transition piece (TP) antenna (20) for mounting internally in a wind turbine transition piece (3), and wherein the repeater is also adapted to be in communication with the internal TP antenna, the repeater being further configured to transmit radio signals received with the external antenna with the usable TP antenna, and vice versa.

The communication system of claim 1, wherein the digital two-way radio system is a terrestrial trunked radio (TETRA) system.

A communication system according to any one of the preceding claims, wherein the external antenna (12) is a radiant antenna.

The communication system according to any one of the preceding claims, wherein the inner tower antenna (16) is a directional circularly polarized antenna.

A communication system according to any one of the preceding claims, wherein the internal tower antenna (16) is a flat panel antenna.

Communication system according to any one of the preceding claims, wherein the internal TP antenna (20) is a directional circularly polarized antenna.

Communication system according to any one of the preceding claims, wherein the internal TP antenna (20) is a flat panel antenna.

A communication system according to any one of the preceding claims, wherein the repeater (14) is a trunk mode operation / trunk mode operation (TMO / TMO) repeater.

A communication system according to any one of claims 2-8, wherein the repeater (14) is a TETRA repeater and optionally the external and / or internal antennas are configured for an Rx / Tx channel separation of nominally 14.5MHz.

A communication system according to any one of claims 1-8, wherein the repeater (14) and optionally the external (12) and / or internal antennas (16, 20) are configured for an Rx / Tx channel separation of nominally 7MHz.

A communication system according to any one of the preceding claims, wherein the repeater (14) is configured to provide a reduced antenna transmitter power to the internal TP antenna (20) when compared to the antenna transmitter power of the internal tower antenna (16).

A communication system according to any one of the preceding claims, wherein the repeater (14) is adapted to send state messages indicating an operational status of the communication system, preferably via a Simple Network Management Protocol (SNMP) module covered by the repeater.

A wind turbine (1) characterized in that it comprises the wind turbine radio communication system (10) according to any one of the preceding claims.

The wind turbine of claim 13, wherein the wind turbine is an offshore wind turbine.

A wind turbine according to any one of claims 13-14, wherein the inner tower antenna (16) is mounted in a lower part of the wind turbine tower (2) and oriented to transmit in a generally upward vertical direction (18).

The wind turbine of any one of claims 13-14, wherein the internal TP antenna is mounted in an upper portion of the wind turbine junction (3) or in a lower portion of the wind turbine tower (2), and oriented to transmit in a conventional downward vertical direction (22).