JPH04185233A - Aerogenerator facility - Google Patents

Abstract

PURPOSE:To smooth the change of output in variable output operation by providing a flywheel generator/motor, which serves as a motor when the output from an aerogenerator is large and which serves as a generator driven by the kinetic energy stored in the flywheel when the aerogenerator output is small. CONSTITUTION:When a flywheel generator/motor 4A is operated as a generator with Pfw positive, kinetic energy stored in inertia is converted into electrical energy and the rotational speed decreases. When the flywheel generator-motor 4A is operated as a motor with Pfw negative, input from the system is converted into accelerating force to increase the rotational speed and the face is stored as kinetic energy. The flywheel generator-motor 4A thus stores up and transmits the change of output Pg as the kinetic energy of the flywheel and smooths the change of the electric power.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to wind power generation equipment that is operated while being connected to an electric power system, and particularly relates to a wind power generation facility that is connected to a small-scale electric power system. This relates to wind power generation equipment that can reduce frequency fluctuations.

(Prior Art) FIG. 4 shows a general configuration of wind power generation equipment that is operated while being connected to an electric power system.

In FIG. 4, the wind power generation equipment 3 connected to the power system 1 via the parallel circuit breaker 2 includes a wind turbine 3A, a synchronous generator 3
B. Consists of a speed generator 3C, a wind turbine control device 3D, an output control device 3E, a frequency replacement device [3F, a main transformer 3G, and a filter 3H.

When the wind turbine 3A rotates in response to wind power, the synchronous generator 3B and speed generator 3C that are shaft-coupled thereto rotate, and when the rotational speed of the synchronous generator 3B reaches a predetermined value, the synchronous generator 3B
Excitation is applied to the synchronous generator 3B, which generates a voltage. When the rotation further increases, the output control device 3E starts operating, and an output signal is output to the frequency conversion device [3F, and the frequency conversion device 3F receives the signal. The voltage of the synchronous generator 3B is converted to the frequency of the power grid 1 according to the frequency of the power grid 1, and is sent to the power grid 1 through the main transformer 3G.The filter 3H is provided to remove voltage waveform distortion caused by the frequency converter 3F. There is.

When the wind power is weak, the wind turbine control bag W3D fixedly controls the wind turbine 3A so that it receives the best wind power, and the output control bag [3E controls the rotation speed to a predetermined speed according to the rotation speed signal obtained from the speed generator 3C. When within the range, an output signal corresponding to the rotational speed is output to the frequency converter 3F. In this state, the electric power (output) sent from the wind power generation equipment 3 to the power system a1 is completely left to the wind, resulting in so-called variable output operation.

When the wind power is strong and reaches a predetermined rotation speed and rated output, the output control device 3E maintains the output signal at the rated value, and the wind turbine control device 3D controls the wind power of the wind turbine 3A to prevent the rotation speed from increasing abnormally. Therefore, when the wind power is strong, the power sent from the wind power generation equipment 3 to the power grid 1 is constant, resulting in so-called constant output operation. Therefore, in conventional wind power generation equipment, the wider the range of variable output operation, the more
More wind power will be available for power generation.

(Problem to be solved by the invention) Generally, when wind power generation equipment is operated with variable output.

As the total power generated by the power system changes, the frequency of the power system changes. This frequency fluctuation can be suppressed by adjusting other generators that can control the output of the power system, but if the wind power generation equipment accounts for a large proportion of the total power generated by the power system and its output changes rapidly, It is not possible to suppress the frequency fluctuation to the desired level by controlling other generators.

One possible way to alleviate this inconvenience is to improve the characteristics of the wind turbine or increase the inertia of the wind turbine generator to slow down the change in output in response to changes in wind power. There is a problem in that the strength and economy of the wind turbine generator tower must be sacrificed.

The present invention can smooth out output fluctuations during variable output operation and alleviate frequency fluctuations in the power system by simply adding equipment to compensate for output fluctuations without making any special changes to the wind power generation equipment itself. The aim is to provide wind power generation equipment particularly suitable for small-scale power systems.

[Structure of the invention]

(Means and effects for solving the problems) The present invention connects a flywheel generator motor in parallel to conventional wind power generation equipment, and controls the input and output of the flywheel generator motor based on fluctuations in the output of the wind power generation equipment. When the output of the wind power generation equipment is increasing, the flywheel generator motor is controlled in the direction of the electric motor, and when the output of the wind power generation equipment is decreasing, the flywheel generator motor is controlled in the direction of the generator. As a result, the output fluctuations of the wind power generation equipment including the flywheel generator motor are moderated, and the frequency fluctuations of the power system to which the wind power generation equipment is connected are reduced.

(Example) An example of the present invention is shown in FIG. Figure 1 shows the conventional 4th
Output fluctuation slowing equipment 4, which is surrounded by a broken line, has been added to the figure.

The output fluctuation slowing equipment 4 is a wire-wound induction motor 4 with large inertia.
A, input/output control device 4B that controls the secondary current of the wire-wound induction machine 4A and its input/output power, wire-wound induction machine 4
Resolver 4C that detects the rotor position Sr'V required for secondary current control of A, target value control device 4D that outputs the input/output power target value Pref of the wound induction machine 4A to the input/output control device 4B, instrument voltage A power detector 4E is provided which receives voltage and current from the transformer PTI and the instrument current transformer CT1, detects the output pg of the wind power generation equipment main body 3, and outputs a corresponding output signal pgd.

The wound induction machine 4A has a large inertia and is configured as a type of flywheel generator-motor that can operate both as a generator and as an electric motor by controlling the secondary current.

Further, FIG. 2 shows an example of the configuration of the target value control device 4D, in which 4D2 is an imperfect differentiation circuit that inputs the power signal Pgd and obtains its incomplete differentiation value PKd.

4D4 is the target value S ref of the rotation speed of the generator motor 4A
This is a speed target value generation circuit that generates a speed target value. Also S fvg
is the rotational speed signal of the generator motor 4A.

This is obtained by converting the rotor position signal SFV during the operation process of the input/output control device 4B. Further, 4D5 is an addition circuit that calculates the deviation between the speed target value S ref and the rotational speed signal S filg, and 406 is a limit circuit that limits the magnitude of the speed deviation signal.

The limited speed deviation signal becomes Prs.

41) 3 is an adder circuit that combines the signal Pgd and the signal prs with the polarity shown, and the combined signal is applied to the generator motor 4A.
becomes the target value P ref of the input/output power.

Further, 4D7 is a power limit detection circuit that detects that the output pg has reached the 1- limit, and 4D9 is a power lower limit circuit that detects that the output Pt has reached the lower limit. Also 4 guns) 8
and 4D10 is a timer, and power upper limit detection circuit 4r
] 7 and the power lower limit detection circuit 4) 9 continue to operate and generate the signal SuP and the signal sd.

The signal SuP and the signal Sdv are the speed target value generation circuit 4D.
4, and when the signal Sup comes, the speed target value generating circuit 4D4 slowly changes the speed target value 5ref to an appropriate value on the upper limit side from the center of the allowable speed range of the generator motor 4A, and when the signal Sdw comes, the speed Slowly change the target value S ref to an appropriate value on the lower limit side of the center of the allowable speed range,
When no signal is received, the speed target value 5ref is slowly changed to approximately the center of the allowable speed range.

When the wind power generation equipment main body 2 is in variable output operation, the output P fluctuates, and the signal P corresponding to the output P customer also fluctuates in the same way. Incomplete differentiator circuit 41)2 for signal pgd
When passed through, the incomplete differential value pgd is obtained, and if the signals P, . . . 8 are ignored at two points, Pref=-Pgd.

Therefore, the input/output power PfV of the flywheel generator motor 4A controlled with the signal Pref as the target value 7 is (Pg
ci), and the power Pt output from the entire wind power generation facility to the power grid 1 is Pt,=Pgd.

For the sake of simplicity, assuming that the output Pg fluctuates like a rectangular wave, the signals and power of each part change as shown in FIG.

In reality, the wind power generation equipment main body 2 also has inertia, and the output control device [3E is also controlled to prevent sudden changes in the output Pg within the permissible range of rotational speed fluctuations of the wind turbine system. The change in the output Pg does not become a perfect rectangular wave, but a slightly gentle fluctuation.

When the output Pg fluctuates like a rectangular wave, the signal (Pgd)
is a signal that suddenly changes in the negative direction when the output P is rising, changes suddenly in the positive direction when the output Pg is falling, and attenuates when the output P is constant. Electric power Pfw is Iko (
Since the power PtJ, which is the sum of the power Pfw and the output Pg, is controlled to be equal to the power Pgd), the power PtJ, which is the sum of the power Pfw and the output Pg, has a waveform in which the abrupt changes are smoother than the output Pg, as shown in the figure.

The operation of the flywheel generator motor 4A itself when controlled in this manner is as follows. That is, as mentioned above, the flywheel generator motor 4A is a wound type induction machine with large inertia, and supplies a secondary current with a frequency equal to the difference between the frequency of the power system 1 and the rotational speed of the wound type induction machine to the secondary winding. This allows operation at any rotational speed within the allowable range determined by the equipment's capabilities. Furthermore, by changing the phase of the secondary current, the wire-wound induction machine is turned into a generator state (Pfw
It is possible to control the motor state (positive, the power flow is in the direction of the arrow in FIG. 1) or the motor state (negative, the power flow is in the opposite direction of the arrow in FIG. 1).

When operating in a generator state (Pfw positive), the kinetic energy stored in the inertia is converted into electrical energy and the rotational speed decreases, and when operating in a motor state (Pfw negative), the input from the grid accelerates. It is converted into force and the rotational speed increases,
Stored as kinetic energy. In this way, the flywheel generator-motor 4A smoothes changes in the electric power PtJ by storing and releasing fluctuations in the output pg as kinetic energy of the flywheel (inertia of the entire rotating body), and the rotational speed of the generator-motor 4A is It fluctuates depending on the input and output of electricity.

The rotational speed of the flywheel generator motor 4A must be within a permissible range; if the permissible upper limit speed is reached, the motor cannot continue to accelerate; on the other hand, if the permissible lower limit speed is reached, the generator operation can no longer be continued. Since deceleration is not possible, the input/output control device 4B is required to have an operation restriction function when such an operating limit is reached.

Further, the signal P9 of the target value control device t4D is
This is a signal to prevent the possibility that A reaches the limit of its permissible speed and the operation of the input/output control device 4B is restricted, thereby impairing the smoothing operation of changes in power ptx.

As mentioned above, the speed target value S ref when the wind power generation equipment main body 2 is operating with variable output is approximately in the center of the allowable range of the generator motor 4A, and the difference between this speed target value S Pef and the actual rotational speed signal Sfvg is The signal p produced by the deviation
rs is a power target value for bringing the rotational speed of 1 generator motor 4A to approximately the center of the allowable speed range, and therefore, the power target value P ref is a power target value for bringing the rotational speed of 1 generator motor 4A to approximately the center of the allowable speed range. Electric power is included, and this acts as a force to return the rotational speed of the generator motor 4A to approximately the center of the allowable speed range.

Constant power operation continues for a set time (set by timer 4D8), or the state of zero output pg continues for a set time (set by timer 4D10).
), the speed target value S ref is changed, and the rotation speed of the generator motor 4A is set to a value that increases the rotation speed change range necessary to alleviate the next fluctuation in the output Pg. controlled.

According to the above embodiment, when the output of the wind power generation equipment main body 2 is fluctuating, the flywheel generator motor operates to compensate for the fluctuation in the output of the wind power generation equipment main body 2, and includes the flywheel generator motor. The output of the entire wind power generation facility is slowed down, and even in environments with severe wind fluctuations, the overall output fluctuation is slowed down.

This suppresses frequency fluctuations in the power system to which the wind power generator is connected.

In the above example, a synchronous machine is used as one generator, and its output is connected to the power grid using a frequency converter, but if the wind power generation equipment itself can be connected to the power grid, this The system is not limited to this type, and for example, it may be configured as a wound type induction machine similar to the flywheel generator motor in this embodiment.

Furthermore, the flywheel generator motor of this embodiment is as follows.

Although a wound type induction machine with large inertia is used, any device that can store the energy necessary for mitigating the output fluctuations of the wind power generation equipment for the necessary time and freely input and output the energy may be used.For example, the wind power generation in this example Similar to the equipment itself, it is possible to use a combination of a synchronous machine and a frequency converter, and an energy storage system that combines a superconducting coil and a converter.
per-conductiveMagnetic-co
It is also possible to use il Energy 5tore).

In addition, to control the flywheel generator motor of this embodiment,
A function is added to control the speed to a predetermined value,
Depending on the inertia of the flywheel generator motor, the nature of wind fluctuations at the installation location, and the scale of the power system, the speed control function may be omitted.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to slow down the output fluctuations of wind power generation equipment whose output fluctuates due to wind power fluctuations, so it is possible to reduce frequency fluctuations in the power system to which the wind power generation equipment is connected. This makes it possible to connect to small-scale power grids.

Especially in small-scale power systems such as those on remote islands, most of the power generation equipment uses diesel generators, and the cost of generating electricity is high.
In addition, there are many places where the annual average wind power is strong and suitable for wind power generation, so installing wind power generation equipment to which the present invention is applied will have an extremely large economic effect.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing one embodiment of the present invention, and Fig. 2 is a system diagram showing an embodiment of the present invention.
FIG. 3 is an explanatory diagram showing the operation of the present invention, and FIG. 4 is a system diagram showing an example of conventional wind power generation equipment. 1... Power system, 2... Parallel circuit breaker 3.
・Wind power generation equipment main body, 3A-... Wind turbine 3B... Synchronous generator, 3C... Speed generator 3D... Wind turbine control device, 3E... Output control device 3F... Frequency conversion device, 3G ...Main transformer 3H...Filter, 4.
...Output fluctuation slowing equipment 4A...Flywheel generator motor 4B, input/output side'S device, 4C...Resolver 4D, target value control device, 4D1...Power detector 4D2...Incomplete differential circuit 4D4...Speed target value generation circuit 4D3.4D5...Addition circuit 4D6...Limit circuit 4D7...Power upper limit detection circuit 4D9...Power lower limit detection circuit 4D8.4D10...Timer agent Patent attorney Yoshiaki Inomata ( 1 other person) Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] In a wind power generation facility equipped with a wind power generator connected to a constant frequency power system and operated, the wind power generator is connected in parallel to the output side of the wind power generator, and when the output of the wind power generator is large, it becomes an electric motor and accelerates the flywheel. A wind power generation facility characterized by comprising a flywheel generator-motor that stores the kinetic energy as kinetic energy and also becomes a generator when the output of the wind power generator is small and outputs the kinetic energy stored in the flywheel as electric power.