JPS6238936B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for synchronizing generators when a power plant, particularly a wind power plant, is added to a power grid.

In a general power plant, a speed governor adjusts the mechanical input, and the rotation speed, that is, the frequency, of the generator can be kept constant, or the output can be adjusted in synchronization with the frequency of the grid. However, in a wind power generation system driven by a huge wind turbine, it is almost impossible to provide a speed regulating function to control the wind energy, so fluctuations in wind energy directly result in fluctuations in generator output. Succession,
With the current system configuration, a generator cannot be added to the grid. For this reason, conventional power generation systems have been used in which the output of the generator is first converted to DC, and then reversely converted from DC/AC using an inverter to match the frequency of the grid before being added to the grid. ing. Normally, as an inverter device serving as this frequency converter, a self-commutating inverter device having a self-compulsory rectification circuit or the like is normally employed.

However, in power plants such as wind power plants that rely on wind energy, it is not appropriate to adopt self-commutated inverter devices that have this expensive self-compulsory rectification circuit, etc., considering the power generation capacity of the wind power plant. isn't it. Furthermore, since a synchronization adjustment device is required to perform phase control of the inverter device upon synchronization, it is not economical and is an obstacle in wind power plants.

The present invention was made in view of the above-mentioned circumstances, and its purpose is to use a load commutation type inverter device as an inverter device used in the power generation system of a power plant, and to quickly connect the generator of the power plant to the grid. Moreover, it is an object of the present invention to provide an economically advantageous method for synchronizing a generator, which can reliably synchronize the generator.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the main circuit configuration of a wind power generation system, and in the figure, reference numeral 1 denotes a generator in a power plant driven by a wind turbine (not shown). 2
is a rectifier that converts the output of generator 1 into direct current,
The converted output is sent out through the smoothing reactor 3. Reference numeral 4 denotes a load commutation type inverter device that reversely converts the DC output supplied through the smoothing reactor 3 to AC output. and sends it out to the system bus 7. Further, 8 is a gate control device that generates an ignition pulse as a gate control signal for the inverter device 4, and 9 is a rotation speed detector that detects the rotation speed of the generator 1. Therefore, it operates and closes a field magnet and a disconnector (not shown). Reference numeral 10 denotes a voltage detection relay that detects the output voltage of the generator 1 obtained via the voltage transformer 11. It detects and operates. On the other hand, 12 is a voltage detection relay that detects the voltage of the grid bus 7 obtained through the voltage transformer 13, and detects a voltage higher than a specified value to confirm that the grid voltage is a voltage that can be automatically synchronized. It detects and operates.

Next, a method for synchronizing the generators in the wind power generation system having such a configuration will be described with reference to FIG. 2. When the generator 1 of such a system is synchronously connected to the grid 7, first of all, the gate control device 8 that controls the gate of the inverter device is
Keep it locked. In this state, when a wind turbine (not shown) of the wind power plant receives wind energy and starts rotating, the generator 1 is driven and rotated. When the rotational speed of the generator 1 exceeds a predetermined value, the rotational speed detector 9 detects this and operates b, and turns on a field generator or disconnector (not shown) c. As a result, voltage begins to be generated in the generator 1. Then, this generator 1
The output of is converted into DC power by the rectifier 2,
From this, the DC power is converted into a higher quality and smoother DC power through the smoothing reactor 3, and is supplied to the inverter device 4 as its DC input power. At the same time, when the output voltage of the generator 1 reaches a predetermined value d or higher, it is detected through the voltage transformer 11 that an output voltage that allows the generator 1 to be added to the grid is being sent out. The voltage detection relay 10 operates e.
Next, the operating condition e of this voltage detection relay 10,
Gate lock confirmation condition f of the gate control device 8
As a result of this, AC power is supplied from the system bus 7 to the inverter device 4 by turning on the line disconnector 6 for connection to the system and connecting the inverter device 4 to the system 7. Then, the voltage of the system 7 is detected by the voltage detection relay 12 through the voltage transformer 13, and on the condition that the voltage detection relay 12 is activated because it is a system voltage that can be automatically synchronized. The gate control device 8 that controls the inverter device 4 is unlocked, and the output signal of the gate control device 8 is applied to the gate of the inverter device 4 as its firing pulse signal. As a result, the inverter device 4 is operated, and the DC power supplied from the rectifier 2 through the smoothing reactor 3 is inversely converted to DC/AC in synchronization with the AC power source of the system 7, and an output equal to the frequency of the system 7 is sent out. By doing so, the generator 1 is automatically automatically synchronized and added to the system 7, and the generator 1 is operated in parallel as it is, h, and the synchronization of the generator 1 to the system 7 is completed.

In this way, the generator 1 driven by the windmill
A rectifier 2 converts the output voltage into a DC power source, which is then passed through a smoothing reactor 3 to a load commutation type inverter device 4 whose gate is controlled to fire by an output pulse signal from a gate controller 8. In addition, in a wind power generation system configured to reversely convert the DC power source into an AC power source and send it out to the grid through the step-up transformer 5 and the cable disconnector 6, the generator 1 can be synchronously connected to the grid 7. When doing so, the gate control device 8 of the inverter device 4 is first locked, and then the voltage detection relay 10 confirms that the output voltage of the generator 1 has reached a predetermined value or higher. The inverter device 4 is connected to the system 7 by turning on the disconnector 6, and then the voltage detection relay 1 detects that the voltage of the system 7 is above a predetermined value.
2, release the lock on the gate control device 8 and apply the ignition pulse signal, which is the control signal, to the gate of the inverter device 4,
The generator 1 is connected to the grid 7 synchronously.

Therefore, the generator 1 of the wind power plant can be quickly and reliably connected to the system 7, and its reliability is extremely high. In addition, since a load commutation type inverter device is used as the inverter device 4 instead of a conventional self-commutating type inverter device having a self-forced commutation circuit etc. which is generally used, it is possible to reduce the cost. Synchronous input as described above can be performed. Furthermore, there is no need for a synchronization adjustment device or the like for controlling the phase of the inverter device when synchronizing the inverter device as in the prior art, resulting in an even more economically superior product.

It should be noted that the present invention is not limited to the above embodiments, but can also be implemented in the following manner.

For example, the rectifier 2 in the above embodiment is
Even if the inverter device that performs AC/DC forward conversion is configured to perform firing angle control and control the input DC power source of the inverter device 4, synchronization can be performed in the same manner.

In addition, it goes without saying that the present invention can be implemented with various modifications without changing the gist thereof.

As explained above, according to the present invention, the output of the generator is converted into DC power by the rectifier, and this is converted into AC power by the inverter whose gate is controlled by the gate control device. In a power generation system configured to send electricity to the grid,
When the generator is synchronously connected to the grid, the gate control device is first locked, then the inverter device is connected to the grid, and then the gate control device is unlocked and the gate ignition signal is given to the inverter device. As a result, a load commutation type inverter device is used as an inverter device, and the generators of the power plant can be quickly and reliably synchronized into the grid.This is an economically advantageous and highly reliable generator synchronization method. We can provide information on how to enter.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of a main circuit of a wind power generation system, and FIG. 2 is a diagram for explaining an embodiment of the present invention. 1... Generator, 2... Rectifier, 3... Smoothing reactor, 4... Inverter device, 5... Transformer, 6... Line breaker, 7... System bus, 8... Gate control device , 9... Rotation speed detector, 10, 12
...Voltage detection relay, 11, 13...Voltage transformer.

Claims (1)

[Claims] 1. A generator output is converted into a DC power source by a rectifier, and this is converted into an AC power source by an inverter device whose gate can be controlled to start and turn off by a gate control device. In a power generation system configured to be able to send power to the grid via a generator, when the generator is added to the grid by turning on the cutter,
First, the gate control device that controls the inverter device is put into a lock state, and then the shield disconnector is turned on to put the inverter device into the grid,
A method for synchronizing a generator, characterized in that the gate control device is then unlocked and the ignition signal is applied to the gate of the inverter device to synchronize the generator into the grid. 2. The method for synchronizing a generator according to claim 1, wherein the inverter device is a load commutation type inverter device.