EP3061179A1

EP3061179A1 - Power plant

Info

Publication number: EP3061179A1
Application number: EP14808931.1A
Authority: EP
Inventors: Hans-Günter ECKEL; Magdalena GIERSCHNER; Hans-Joachim Knaak
Original assignee: Siemens AG
Current assignee: Siemens Energy Global GmbH and Co KG
Priority date: 2013-12-20
Filing date: 2014-12-02
Publication date: 2016-08-31
Also published as: JP6370386B2; CN105830328A; JP2017501672A; DE102013226987A1; KR101918145B1; KR20160087888A; CN105830328B; US20170005479A1; WO2015090936A1

Abstract

The invention relates, inter alia, to a power plant (10) comprising an internal AC voltage grid (20), a multiplicity of electrical energy generation units (30, 31) which are connected to the internal AC voltage grid (20), and at least one HVDC transmission device (40), which is connected to the internal AC voltage grid (20), is connectable to an external AC voltage grid (50) via a DC link and enables energy transmission from the internal AC voltage grid (20) in the direction of the external AC voltage grid (50). In accordance with the invention, provision is made for the energy generation units (30, 31) either to feed their power into the internal AC voltage grid (20) via a power electronics converter or to feed their power into the internal AC voltage grid (20) via the stator of a double fed asynchronous machine, the rotor of which is fed via a power electronics converter, and for the energy generation units (30, 31) to each have a synchronization device (60), which is suitable for regulating the generation of the output voltage of the respective energy generation unit (30, 31) or the feeding of the output current by the respective energy generation unit (30, 31) in such a way that the phase angle of the output voltage or the phase angle of the output current has a setpoint phase angle (Δϕ), which is preset to the respective energy generation unit (30, 31), with respect to a synchronization signal (S) applied on the input side.

Description

description

The invention relates to a power plant with an internal AC voltage network, a plurality of electrical power generation units, which are connected to the internal AC power network, and at least one high-voltage DC transmission device, which is connected to the internal AC power network, via a DC link to an external AC voltage network can be connected and allows energy transfer from the internal AC voltage network in the direction of the external AC voltage network.

Power plants of the type described are known as wind farms, in which the power generation units are formed by wind turbines, or as photovoltaic parks, in which the power generation units are formed by photovoltaic systems. The high-voltage DC transmission equipment used in these power plants each have self-commutated rectifiers on the internal AC power network of the power plant. The invention has for its object to provide a power plant, which can be realized more cost-effective than previous power plants.

This object is achieved by a power plant with the features according to claim 1. Advantageous embodiments of the power plant according to the invention are specified in subclaims.

According to the invention, the power generation units feed their power into the internal AC voltage network either via a power-electronic converter or via the stator of a doubly-fed asynchronous machine whose rotor is connected via a power electronics unit. inverter is fed, feed into the internal AC power grid and the power generation units each have a synchronizer, which is suitable to regulate the generation of the output voltage of the respective energy generating unit or the feeding of the output current through the respective power generation unit such that the phase position of the output voltage or the phase position of the output current has a desired phase position predetermined by the respective energy generation unit with respect to a synchronization signal applied on the input side.

A significant advantage of the power plant according to the invention is the fact that in this the high-voltage DC transmission device on the part of the internal AC power network does not have to be self-guided, but can be net-guided. In other words, in the power plant according to the invention it is possible to use line-driven rectifiers instead of self-commutated rectifiers on the side of the internal AC voltage network, which can save considerable costs; because grid-controlled rectifiers are technically simpler and therefore less expensive to produce than self-commutated rectifiers. The use of a side of the internal AC voltage network-controlled high-voltage DC transmission device is inventively possible because sufficient stabilization of the internal AC voltage network is carried out by the synchronization of the power generation units, so that it does not need self-guidance of the high-voltage DC transmission device on the part of the internal AC voltage network ,

As already mentioned, it is considered advantageous with regard to minimum costs if the high-voltage direct-current transmission device on the connection side to the internal AC voltage network has at least one line-commutated one

Rectifier has. In other words, the high-voltage DC transmission device on the connection side to the internal AC power network is preferably one mains-powered high-voltage direct current transmission device.

Overall, it is advantageous if the high-voltage DC transmission device on the side of the internal AC voltage network is a mains-driven high-voltage DC transmission device and on the side of the external AC voltage network is a self-commutated high-voltage DC transmission device.

In order to ensure an emergency operation or a coverage of the internal needs of the internal AC power network even in case of insufficient power generation of the power generation units, it is considered advantageous if the high voltage DC transmission device on the connection side to the internal AC voltage network has at least one self-commutated rectifier, which is suitable to work as an inverter and to feed the internal power supply of the internal AC voltage network from the DC side of the high-voltage DC transmission device coming energy into the internal AC power grid. Due to the presence of a self-commutated rectifier, which can operate as an inverter, it is possible to carry out an energy transfer from the external AC voltage network in the direction of the internal AC voltage network if there is insufficient mains voltage there.

Preferably, all power generation units of the power plant are subjected to the same synchronization signal.

With a view to a particularly high stability of the internal AC voltage network, it is considered advantageous if during operation of the power plant at least half of the power generation units the same desired phase position, hereinafter referred to central target phase position, is predetermined and this half of the power generation units their output voltage or generate their output current with the same central target phase position.

In order to compensate reactive power present in the internal AC voltage network or to generate reactive power in the AC voltage network, it is possible for at least one of the energy generation units to specify or specify an individual desired phase position which deviates from the central desired phase position.

For example, it can be provided that an individual desired phase position is predetermined for the at least one energy generation unit, which deviates from the central desired phase position by 90 ° or at least such that the energy generation unit feeds reactive power into the internal AC voltage network.

Preferably, the power plant has a central device, which is connected to all power generation units and is configured such that it sets each power generation unit each a desired phase position.

With a view to a simple transmission of the synchronization signal, it is considered advantageous if the power generation units each have a radio receiver and the radio receivers of the power generation units each receive their synchronization signal by radio.

The synchronization signal may be, for example, the so-called GPS signal (GPS: Global Positioning System); In this case, the radio receivers are preferably GPS receivers.

The power plant may be, for example, a wind farm or a photovoltaic park, in which the power generation units are formed by wind turbines and / or photovoltaic systems. The internal AC voltage network can be, for example, a polyphase network, in particular a three-phase network. The invention also relates to a power generation unit for a power plant as described above. With regard to such a power generation unit, it is provided according to the invention that it has a synchronizing device which is suitable for processing an input signal applied to the input side and the phase position of an output voltage generated by the power generation unit or the phase position of an output current fed into the internal AC power supply by the power generation unit, and Generation of the output voltage or the feeding of the output current to regulate such that the phase position of the output voltage or the phase position of the output current of the power generating unit predetermined target phase position corresponds. With regard to the advantages of the power generation unit according to the invention, reference is made to the above statements in connection with the power plant according to the invention, since the advantages of the power generation unit according to the invention essentially correspond to those of the power plant according to the invention.

The invention further relates to a method of operating a power plant equipped with an internal AC power network, a plurality of power generation units connected to the internal AC power network, and at least one high voltage DC power transmission device connected to the internal AC power network is. With regard to such a method, it is provided according to the invention that in each case a synchronization signal is fed into the energy generating units and that the energy generating units in each case feed the synchronization signal present on the input side. detection signal as well as the phase position of an output voltage generated by the respective power generation unit or the phase position of a fed from the respective power generation unit in the internal AC voltage output current and control the generation of the output voltage or the feeding of the output current such that the phase position of the output voltage or the phase position of the Output current of the respective power generation unit predetermined target phase position compared to the synchronization signal corresponds.

With regard to the advantages of the method according to the invention, reference is made to the above statements in connection with the power plant according to the invention.

The invention will be explained in more detail with reference to embodiments; thereby show by way of example

Figure 1 shows an embodiment of an inventive

Power plant in which a high voltage

DC transmission device on the part of an internal AC voltage network has a line-commutated rectifier, Figure 2 shows an embodiment of an inventive

Power plant in which a high-voltage DC transmission device on the part of an internal AC voltage network has both a network-controlled rectifier and a self-commutated rectifier,

Figure 3 shows an embodiment of an inventive

Power plant, in which a central device is present, which is connected to all power generation units of the power plant and this each specifies an individual target phase position, and Figure 4 shows an embodiment of a power plant according to the invention, in which a central device is provided which sets the power generation units each an individual desired phase position and in which a high-voltage DC transmission device on the part of the internal AC power network both a mains-powered rectifier and a self-commutated rectifier. For the sake of clarity, the same reference numbers are always used in the figures for identical or comparable components.

1 shows a power plant 10 having an internal AC voltage network 20 and a plurality of connected to the internal AC voltage network 20 power generation units 30 and 31. The internal AC voltage network 20 is also connected to a high-voltage DC transmission device 40, which connects the internal AC voltage network 20 to an external AC voltage network 50 and enables energy transfer from the internal AC voltage network 20 in the direction of the external AC voltage network 50. The high-voltage direct-current transmission device 40 is a line-commutated transmission device on the side of the internal alternating-voltage network 20 and for this purpose has a line-commutated rectifier 41, which is arranged electrically between the internal alternating voltage network 20 and a direct current transmission line 42.

In order to ensure correct operation of the line-commutated rectifier 41 of the high-voltage direct current transmission device 40, it is necessary for the internal alternating voltage network 20 to be sufficiently stable. In order to ensure the stability of the internal AC voltage network 20 despite the large number of existing power generation units 30 and 31, the power generation units 30 and 31 are each because it is equipped with a synchronizing device 60, which is suitable for regulating the generation of the output voltage of the respective energy generating unit or the feeding of the output current through the respective energy generating unit such that the phase position of the output voltage or the phase position of the output current corresponds to a desired phase position specified for the respective energy generating unit , The desired phase position refers to a synchronization signal S present on the input side, which is fed into the synchronization devices 60 of the energy generation units 30 and 31, respectively.

In the exemplary embodiment according to FIG. 1, it is assumed that the transmission of the synchronization signal S to the synchronizers 60 takes place via radio. Alternatively, it is possible to transmit the synchronization signal S in a different way, for example by wire.

The feeding of the electrical power through the energy generating units 30 and 31 into the internal AC voltage network 20 is effected either via a power electronic converter or via the stator of a doubly fed asynchronous machine whose rotor is fed by a power electronic converter. For reasons of clarity, the latter components, that is to say the power electronic converters or the stators of double-fed asynchronous machines, are not explicitly illustrated in FIG.

With regard to the configuration of the high-voltage direct-current transmission device 40, it is considered advantageous if it is a self-commutated transmission device on the side of the external AC voltage network 50 and has a self-commutated converter 45 for this purpose. The power plant 10 according to FIG. 1 can be operated, for example, as follows: The synchronizers 60 of the power generation units 30 and 31, respectively, receive the synchronization signal S, which may be, for example, the well-known GPS location signal (GPS: Global Positioning System), since the GPS location signal has a timestamp suitable for synchronization.

The synchronizing devices 60 evaluate the synchronization signal S and regulate the output voltage or the output current of their respective power generation unit in such a way that the phase position of the output voltage or the phase position of the output current coincides with a desired phase position given individually to the power generation unit with respect to the synchronization signal S present on the input side ,

The synchronization by means of the synchronization signal S thus makes it possible for the energy generation units, without being directly connected to each other, to show a coordinated behavior with regard to the feeding of their energy into the internal AC voltage network 20. By the

Synchronism of the power supply, the internal AC power network 20 is stabilized in terms of grid frequency and voltage level, so that the internal AC voltage network 20 or its stability is sufficient to operate the grid-connected rectifier 41 stable and energy from the internal AC power network 20 via the grid-connected rectifier 41 and the DC transmission line 42nd in the direction of the external alternating voltage network 50 to transmit. FIG. 2 shows a further exemplary embodiment of a power plant in which the energy generation units 30 and 31 are synchronized by means of a synchronization signal S in order to ensure adequate stabilization of the internal AC voltage network 20 for grid-controlled operation of the grid-commutated rectifier 41.

In contrast to the exemplary embodiment according to FIG. 1, the power plant 10 according to FIG. 2 has the internal one AC line 20 facing terminal side of the high-voltage DC transmission device 40 in addition a self-commutated rectifier 46, which is suitable to work as an inverter and fed from the DC transmission line 42 coming energy in the AC voltage network 20. The self-commutated rectifier 46 can thus serve to cover the intrinsic demand of the internal AC voltage network 20 via an energy transfer from the external AC voltage network 50 in the direction of the internal AC voltage network 20, for example, if the power generation units 30 or 31 do not themselves have sufficient power in the internal AC voltage network 20 feed.

3 shows an exemplary embodiment of a power plant 10, in which a central device 100 is present, which is connected to each power generation unit 30 and 31 individually, whether wired or via radio. For reasons of clarity, only the connection between the power generation unit 30 and the central device 100 is explicitly shown in FIG. 1; the remaining connections between the power generation units 31 and the central device 100 are only indicated in FIG. The central device 100 has the task of each energy generating unit 30 or 31 or each synchronizer 60 of the power generation units 30 and 31 each to specify an individual phase Δφ. The synchronizing devices 60 thus receive in addition to the synchronization signal S also their individually predetermined desired phase position Δφ, so that it is possible for them to regulate the output voltage or the output current in such a way that they have the predetermined desired phase position Δφ with respect to the synchronization signal S present on the input side.

In the exemplary embodiment according to FIG. 3, the transmission of the synchronization signal S takes place as a GPS signal via radio and the transmission of the individually predetermined target value. Alternatively, it is possible to transmit the synchronization signal S together with the individual desired phase position Δφ from the central device 100 to the synchronizing devices 60 of the power generation units 30 and 31, for example by wire or by wire Wireless. In the case of a wired transmission can be dispensed radio receiving equipment for receiving a GPS signal, for example.

4 shows an exemplary embodiment of a power plant, in which the high-voltage DC transmission device 40 on the side of the internal AC voltage network 20 in addition to the grid-controlled rectifier 41 also has a self-commutated rectifier 46, which is suitable to work as an inverter and to supply the internal demand of the internal AC voltage network 20 from the DC side of the rectifier 46 or from the DC transmission line 42 energy to be fed into the internal AC voltage network 20, as has already been explained in detail in connection with Figure 2 above. The relevant explanations therefore apply accordingly. While the invention has been further illustrated and described in detail by way of preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention. LIST OF REFERENCE NUMBERS

10 power plant

20 internal AC voltage network

30 power generation unit

31 energy production unit

40 high voltage DC transmission equipment

41 line rectifier

42 DC transmission line

45 self-commutated inverter

46 self-powered rectifier

50 external alternating voltage network

60 synchronizer

100 central facility

S synchronization signal

Δφ set phase position

Claims

claims

1st power plant (10) with

an internal AC voltage network (20),

- A variety of electrical power generation units (30, 31) which are connected to the internal AC voltage network (20), and

- At least one high-voltage DC transmission device (40) which is connected to the internal AC voltage network (20), via a DC connection to an external AC voltage network (50) can be connected and an energy transfer from the internal AC voltage network (20) in the direction of the external AC voltage - network (50) allows

d a d u r c h e c e n c i n e s that

- The power generation units (30, 31) feed their power either via a power electronic converter in the internal AC voltage network (20) or via the stator of a double-fed induction machine whose rotor is fed via a power electronic inverter, feed into the internal AC voltage network (20) and

- The power generation units (30, 31) each one

Synchronizing device (60) which is suitable for controlling the generation of the output voltage of the respective power generation unit (30, 31) or the feeding of the output current through the respective power generation unit (30, 31) such that the phase position of the output voltage or the phase position of the output current one of the respective power generation unit (30, 31) predetermined target phase position (.DELTA..phi.) with respect to an input side applied synchronization signal (S).

2. Power plant (10) according to claim 1,

d a d u r c h e c e n c i n e s that

the high-voltage direct-current transmission device (40) has at least one line-commutated rectifier (41) on the connection side to the internal alternating voltage network (20).

3. Power plant (10) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the high voltage DC transmission means (40) is a mains high voltage DC transmission means (40).

4. power plant (10) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the high voltage DC transmission means (40) on the internal AC power network side (20) is a mains high voltage DC transmission means (40) and on the outside AC power supply network (50) is a self-commutated high voltage DC transmission means (40).

5. Power plant (10) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the high-voltage DC transmission device (40) on the connection side to the internal AC voltage network (20) has at least one self-commutated rectifier (46) which is suitable for operating as an inverter and for covering the intrinsic demand of the internal AC voltage network (20) from the DC side High-voltage DC transmission device (40) to feed incoming energy into the internal AC voltage network (20).

6. Power plant (10) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

all power generation units (30, 31) of the power plant (10) with the same synchronization signal (S) are acted upon.

7. Power plant (10) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

- During operation of the power plant (10) at least half of the energy generating units (30, 31) the same desired phase position (.DELTA..phi.), hereinafter referred to central target phase position, is given and

- That half of the power generation units (30, 31) produce their output voltage or their output current with the same central target phase position.

8. Power plant (10) according to claim 7,

d a d u r c h e c e n c i n e s that

at least one of the energy generating units (30, 31) is predetermined or can be preset an individual desired phase position (Δφ), which deviates from the central desired phase position.

9. power plant (10) according to claim 8,

d a d u r c h e c e n c i n e s that

the at least one energy generating unit (30, 31) is given an individual target phase position (Δφ) which deviates from the central desired phase position by 90 ° or at least such that the energy generating unit (30, 31) feeds reactive power into the internal AC voltage network (20) ,

10. Power plant (10) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the power plant (10) comprises a central device (100) which is connected to all power generation units (30, 31) and is configured such that it specifies a desired phase position (Δφ) for each power generation unit (30, 31).

11. Power plant (10) according to one of the preceding claims,

characterized in that - The power generation units (30, 31) each have a radio receiver and

- The radio receiver of the power generation units (30, 31) each receive their synchronization signal (S) by radio.

12. Power plant (10) according to claim 11,

d a d u r c h e c e n c i n e s that

the radio receivers are GPS receivers.

13. Power plant (10) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

- The power generation units (30, 31) are wind turbines and the power plant (10) forms a wind farm or

the energy generating units (30, 31)

Photovoltaic systems are and the power plant (10) forms a photovoltaic park.

14. Energy generating unit (30, 31) for a power plant (10) according to one of the preceding claims,

d a d u r c h e c e n c i n e s that

the power generation unit (30, 31) a

Synchronizing device (60) which is suitable, an input side applied synchronization signal (S) and the phase position of one of the power generation unit (30, 31) generated output voltage or the phase position of one of the power generation unit (30, 31) in the internal AC voltage network (20) To process fed-in output current and to regulate the generation of the output voltage or the feeding of the output current such that the phase position of the output voltage or the phase position of the output current of one of the power generation unit (30, 31) predetermined target phase position (Δφ) corresponds.

15. A method for operating a power plant (10) which is equipped with an internal AC voltage network (20), a plurality of power generation units (30, 31), which are connected to the internal AC voltage network (20), and at least one high-voltage DC transmission device (40) which is connected to the internal AC voltage network (20),

d a d u r c h e c e n c i n e s that

- in the power generation units (30, 31) one each

Synchronization signal (S) is fed and

- The energy generating units (30, 31) respectively the input side applied synchronization signal (S) and the phase position of one of the respective power generation unit (30, 31) generated output voltage or the phase position of the respective power generation unit (30, 31) in the detect internal AC voltage network (20) fed output current and regulate the generation of the output voltage or the feeding of the output current such that the phase position of the output voltage or the phase position of the output current of the respective power generation unit (30, 31) predetermined desired phase position (.DELTA..phi.) relative to the synchronization signal (S ) corresponds.