JPH05265583A - Wind power generator - Google Patents

Abstract

PURPOSE:To increase the rated output capacity of a generator to a level equivalent to the reception capacity and to obtain a stable power profitably by providing a reception power detecting means and a reception lower limit value setting means, and discharging the excessive power of an induction generator to the outside of a system by a power discharge means when the reception power goes less than a reception lower limit value. CONSTITUTION:When a propeller 8 is rotated by receiving wind, the induction generator 9 is rotated, to be in a power generating state, and a power can be generated by connecting the induction generator 9 to a power generation system R via a bus 10. The reception power can be always detected in real time by a reception detecting means 13, and the minimum level is set by a reception lower limit value setting means 14. When the reception power goes less than the reception lower limit value, a command is outputted to the power discharge means 15, and the output of the induction generator 9 is discharged to the outside of the system by a power discharge means 15 consisting of a reactor and a transistor via a resistor 16. Thereby, it is possible to prevent a reverse tidal current to a reception system from occurring, and to increase and stabilize the output of the generator.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wind turbine generator that supplies electric power to a load from a wind turbine generator connected in parallel to a power distribution system.

[0002]

2. Description of the Related Art In wind power generation, the propeller is rotated by the force of the wind and the generator is driven by the rotating force, so that it is directly affected by the wind speed and the wind direction. Therefore, the output fluctuation of the generator becomes large, and stable power cannot be supplied. For this reason, a method in which a synchronous generator is used to stabilize its output through a power converter and supply it to a load is generally put into practical use.

However, in this case, the power converter is expensive, and unlike the case of the induction generator, an exciting circuit is required, which is problematic in that it is expensive and bulky. A wind turbine generator that can supply stable power using a machine has been proposed.

FIG. 4 shows a wind power generator using a conventional induction generator. In the figure, 1 is a propeller that rotates by receiving wind power, 2 is an induction generator driven by a propeller 1, and 3 is a generator. A bus bar 4 for connecting a power receiving system (power receiving) R to feed power to a feeder, 4 is a feeder for distributing power to a load, and 5 is a reverse power protection relay for detecting reverse power flow to the power receiving side.

Further, FIG. 5 is a power-time characteristic diagram showing an operation pattern of a conventional wind turbine generator.
Is the total load power connected to the feeder 4, and 7 is the output voltage of the wind power generator.

Next, the operation will be described. First, when the propeller 1 receives wind and rotates, the induction generator 2 rotates and enters a state in which power can be generated. Here, electric power is generated by connecting the power receiving system R to the induction generator 2 through the bus 3. In general, the output voltage 7 generated by wind power generation is affected by the wind speed, wind direction, and control speed of the propeller pitch, but typically it is not stable as shown in FIG. ..

On the other hand, if the wind power changes significantly due to gusts or the like, the output of the induction generator 2 exceeds the power required by the total load power 6 connected to the feeder 4, causing reverse flow to the power receiving side, The reverse power protection relay 5 operates. For this reason, the power receiving system R and the induction generator 2 are disconnected, and the feeder 4 falls into a situation of power failure.

Therefore, it is necessary to make the output of the induction generator 2 extremely smaller than the power receiving capacity so as not to exceed the total load electric power 6 connected to the feeder 4 at the maximum. Also,
Since the electric power fluctuation peculiar to the output of the induction generator 2 is always generated in a wavy pattern when the propeller 1 is rotated, naturally, this must also be taken into consideration when considering the reverse flow.

[0009]

Since the conventional wind turbine generator is constructed as described above, reverse power flow will occur unless the power receiving capacity is necessarily larger than the maximum fluctuation of the output of the induction generator 2. The output capacity of the induction generator 2 needs to be smaller than the received power capacity. Therefore, when the instantaneous maximum fluctuation value is taken into consideration, the output of the induction generator 2 becomes extremely small, and the receiving system R with high running cost is used. However, there is a problem in that the renewable energy cannot be effectively used. Note that, as other approximation prior arts, Japanese Patent Laid-Open Nos. 3-22830 and 3-11
There is one described in Japanese Patent Publication No. 130.

The invention of claim 1 has been made to solve the above-mentioned problems, and the rated output capacity of the induction generator can be made equal to the power receiving capacity, whereby natural energy can be effectively used. An object of the present invention is to obtain a wind turbine generator capable of obtaining stable electric power with inexpensive equipment while using it.

Further, the invention of claim 2 provides a wind power generator capable of speeding up and improving the accuracy of the output discharge control of the induction generator when the power received at the power receiving point exceeds the set lower limit of power reception. With the goal.

[0012]

According to a first aspect of the present invention, there is provided a wind turbine generator, which is a power receiving means for detecting power received at a power receiving point in a distribution system, and a power receiving lower limit for setting a power receiving lower limit value at the power receiving point. When the received power at the power receiving point detected by the received power detecting means exceeds the above-mentioned lower limit of receiving power, the power discharging means uses the excess power as a controlled variable to induce It is designed to discharge the surplus output of the generator.

The wind power generator according to a second aspect of the present invention includes a received power detecting means for detecting received power at a receiving point in the distribution system, and a receiving lower limit value setting means for setting a lower receiving limit value at the receiving point. When the received power at the power receiving point detected by the received power detecting means exceeds the above-mentioned lower limit of power reception, the power discharging means controls the amount of power exceeding the output power of the induction generator. And the control amount correcting means corrects the control amount by the instantaneous electric power of the induction generator obtained from the rotation speed of the induction generator.

[0014]

When the received power at the power receiving point exceeds the preset lower limit of the power reception, the power discharging means instantaneously discharges the excess output of the induction generator to the outside of the system, and therefore the load capacity. Can be instantaneously changed to secure a constant received power, and even when wind power becomes unstable, reverse power flow is prevented.

Further, the control amount correction means in the invention of claim 2 is for discharging the output obtained as a difference between the received power at the power receiving point and the set lower limit value of the received power by the instantaneous power obtained from the rotation speed of the induction generator. Correct the control amount at high speed.

[0016]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 8 is a propeller that rotates by receiving wind power, 9 is an induction generator that is rotated by the propeller, and 10 is a busbar for connecting the generator output and the power receiving system R to supply power to the feeder.

Further, 11 is the feeder for distributing power to the load, 12 is a reverse power protection relay for detecting reverse power flow to the power receiving side, and 13 is power receiving power detection for detecting the power received at the power receiving point. Means, 14 is a power receiving lower limit value setting means for setting a lower limit value of the received power, 15 is a power discharging means for discharging a surplus induction generator output to the outside of the grid, and 16 is a combination with the power discharging means 15. This is the resistor used.

Further, 17 is a pulse oscillator provided for detecting the rotation speed of the induction generator 9, and 18 is a rotation speed / generator output conversion means for converting the rotation speed detected by the pulse oscillator 17 into a generator output. It is a control amount correction means that also serves as the control amount.

FIG. 2 is a power-time characteristic diagram showing the operation pattern of the wind turbine generator, 19 is the total load power connected to the feeder 11, and 20 is the output voltage of the induction generator 9. Then, FIG. 3 shows the emission power of the power emission means 15.
A time characteristic chart is shown, and 21 is an output voltage of a surplus generator.

Next, the operation will be described. First, when the propeller 8 receives wind and rotates, the induction generator 9 rotates,
It is ready to generate electricity. Next, the induction generator 9 is connected to the power receiving system R through the bus bar 10 to generate electric power.

In this case, when the wind force changes significantly due to a gust of wind or the like, the output of the induction generator 9 exceeds the electric power required by the total load electric power 19 connected to the feeder 11 as shown in FIG. As described above, reverse power flow is generated on the power receiving side, the reverse power protection relay 12 operates, the power receiving system R and the induction generator 9 are disconnected, and the feeder 11 falls into a power failure.

Therefore, in the present invention, the received power detecting means 1
In 3, the received power is always detected in real time. At this time, the power receiving lower limit setting means 14 receives, for example, 50 kW of power.
By setting the minimum setting like this, if the output of wind power generation increases and the received power decreases, the above 5
The surplus of the output of the induction generator 9 is discharged to the outside of the system so that the power reception does not fall below 0 kW.

That is, when the received power exceeds the lower limit of the received power, a command is output to the power discharging means 15, and the power discharging means 15 including the reactor 15a and the transistor 15b is the induction generator shown in FIG. The output 21 of 9 is discharged to the outside of the system through the resistor 16. In this case, the emitted power is the difference between the lower limit value of received power and the received power. And
If the released electric power is converted into heat by the resistor 16 and stored in the heat storage means or the like, the energy can be effectively used.

Further, even when the total load connected to the feeder 11 is instantly reduced due to a failure or the like, the operation is performed so that the reverse power flow does not occur, so that a stable generator output can be obtained.

Example 2. In the above embodiment, the case where the lower limit of power reception is detected has been described. However, while detecting the rotation of the induction generator 9 and learning the fluctuation of the wind power, the instantaneous electric power is obtained by the control amount correction means 18, and the electric power is released by this. Means 1
If the control of 5 is performed in detail with prediction, the accuracy can be further improved.

That is, since the output Pw of the induction generator 9 is proportional to the rotation speed N, the instantaneous power of the induction generator 9 can be obtained by a certain function of N → Pw. On the other hand, if a delay occurs in the system that extends from the induction generator 9 → bus 10 → power discharging means 15, it is difficult to suppress the fluctuation even if the power is detected only from the power receiving system R. By detecting the electric power, the control amount can be corrected quickly.

[0027]

As described above, according to the invention of claim 1, the received power detecting means for detecting the received power at the power receiving point in the distribution system, and the power receiving lower limit value setting for setting the power receiving lower limit value at the power receiving point. And a means for discharging the surplus of the output of the induction generator by the power discharging means when the received power at the power receiving point detected by the received power detecting means exceeds the power receiving lower limit value. Therefore, it is possible to prevent the occurrence of reverse power flow to the power receiving system, increase the output of the generator, and stabilize it, and obtain the effect of effectively utilizing natural energy.

According to the second aspect of the present invention, there is provided power receiving power detection means for detecting the power received at the power receiving point in the power distribution system, and power receiving lower limit value setting means for setting the power receiving lower limit value at the power receiving point. When the received power at the power receiving point detected by the received power detecting means exceeds the lower limit of the receiving power, the power discharging means controls the excess power as a control amount, and the surplus output of the induction generator. In addition, the control amount correction means is configured to correct the control amount by the instantaneous power of the induction generator obtained from the rotation speed of the induction generator. There is an effect that it is possible to rapidly correct the output emission control amount of the induction generator, which is obtained as a difference from the lower limit value.

[Brief description of drawings]

FIG. 1 is a single line connection diagram showing a wind turbine generator according to an embodiment of the present invention.

2 is a power-time characteristic diagram showing an output example of the wind turbine generator in FIG. 1. FIG.

FIG. 3 is an emission power-time characteristic diagram showing an output example of the power emission means in FIG.

FIG. 4 is a single line connection diagram showing a conventional wind turbine generator.

FIG. 5 is a power-time characteristic diagram showing an output example of a conventional wind turbine generator.

[Explanation of symbols]

 8 propeller 9 induction generator 13 received power detection means 14 received power lower limit setting means 15 power emission means 18 controlled variable correction means

Claims (2)

[Claims] 1. A wind turbine generator that is connected in parallel to a power distribution system of an electric power company and supplies power to a load from an induction generator driven by a propeller that rotates by receiving wind power, in a power receiving point of the power distribution system. In the case where the received power at the receiving point detected by the received power detecting means for detecting, the receiving lower limit value setting means for setting the receiving lower limit value at the receiving point and the receiving point detected by the received power detecting means exceeds the receiving lower limit value, A wind power generator comprising: a power discharge means for discharging the surplus of the output of the induction generator by using the excess power as a control amount. 2. A wind power generator that is connected in parallel to a power distribution system of an electric power company and supplies power to a load from an induction generator driven by a propeller that receives wind and rotates, and receives power from a power receiving point in the power distribution system. In the case where the received power at the receiving point detected by the received power detecting means for detecting, the receiving lower limit value setting means for setting the receiving lower limit value at the receiving point and the receiving point detected by the received power detecting means exceeds the receiving lower limit value, , The amount of power that exceeds the amount of control is used as a control amount, and the amount of control is controlled by the power discharging means that discharges the excess of the output of the induction generator and the instantaneous power of the induction generator obtained from the number of revolutions of the induction generator. And a control amount correcting means for correcting