JP3876562B2 - System linkage method for natural energy power generation equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a grid connection method for a natural energy power generation apparatus, and in particular, operates a plurality of power generation apparatuses that use natural energy as an energy source, such as sunlight, wind power, tidal power, and the like, linked to each other in parallel with a power system. More particularly, the present invention relates to a system linkage method for a natural energy power generation apparatus that actively monitors an abnormality of a linked power system and prevents an independent operation of the power generation apparatus.
[0002]
[Prior art]
When a power generator using natural energy, such as solar power generation, is connected to an existing power system for linked operation, if a power failure occurs due to an accident on the power system side, this is detected immediately. Therefore, it is necessary to stop the operation of the power generation apparatus so that the power generation apparatus continues to operate independently and does not charge the power system.
[0003]
As a method for this, according to the “System Linkage Technical Requirements Guidelines” published by the Ministry of International Trade and Industry, a voltage phase that detects an instantaneous voltage phase jump in which the inverter output at the time of transition to single operation changes from a power factor 1 operation to a load power factor. Jump detection method, third harmonic voltage sudden increase detection method to detect voltage distortion sudden increase due to transformer excitation current supply at the time of single operation shift, frequency change due mainly to imbalance between generated power and load at the time of single operation shift It is required to have a passive method such as a frequency change rate detection method for detecting the frequency and an active method.
[0004]
As the latter active method, the power output from the power generator is periodically disturbed, and the influence of the effect differs depending on whether the power system fails or not. ing. Specifically, for example, a frequency bias is applied to the internal oscillator of the inverter, and a frequency shift method for detecting a frequency change that appears at the time of single operation, a periodic active power fluctuation is given to the inverter output, and at the time of single operation. Active power fluctuation system that detects voltage, current, or frequency fluctuations that appear, gives reactive power fluctuations periodically to the inverter output, and reactive power fluctuation system that detects frequency fluctuations etc. that appear during isolated operation, in parallel with the inverter output There is a load variation method in which impedance is instantaneously and periodically inserted to detect a sudden change in voltage or current.
[0005]
When a plurality of power generation devices linked to the power system are operated in parallel, in the conventional method, the power generation devices installed individually execute the active detection method at the timing of each. When the number of such power generation devices linked to one power system is small, even if each power generation device executes an active detection method for each, the mutual interference is slight, and its capability Will not be damaged.
[0006]
However, when the number of parallel devices increases, there is a problem that the function of the power generation device does not operate normally due to the influence of other power generation devices. Even in the currently marketed solar power generators, the limit is 5-6 units. However, in the field of industrial use in the future, such a power generation device will be introduced. For example, in the case of solar power generation, the number of units in parallel tends to increase because it is necessary to install the solar cells in a distributed manner. .
[0007]
As a countermeasure, Japanese Patent Laid-Open No. 10-94174 proposes a method of synchronizing the active detection methods of a plurality of power generators.
[0008]
Japanese Patent Laid-Open No. 10-155240 proposes a method of simultaneously performing an active detection method by driving a plurality of power conversion devices with a single control device.
[0009]
[Problems to be solved by the invention]
However, in these methods, a large-scale apparatus has a large disturbance factor, and there is a concern about the influence on private facilities even if the power system is not affected.
[0010]
The present invention has been made to solve the above-described conventional problems, and it is an object of the present invention to allow the active islanding detection function to function normally even when the number of parallel operation increases.
[0011]
[Means for Solving the Problems]
In the present invention, when a plurality of power generation devices that use natural energy as an energy source are operated in parallel with each other and connected to the power system, the power generation system is actively monitored for abnormalities in the associated power systems. In the grid connection method for natural energy power generation equipment that prevents operation, only a part of the power generation equipment determines the function that actively generates disturbances to detect power system abnormalities, and power system abnormality The above-mentioned problem is solved by outputting a power generation stop command to a power generator other than the master machine when an abnormality is detected by the master machine .
[0013]
Furthermore, a power generation device other than the master machine is also provided with a function of determining an abnormality in the power system so that the power generation apparatus other than the master machine is informed of the timing at which the master machine generates a disturbance. The result of the disturbance is determined by each power generator, and power generation is stopped when an abnormality is detected.
[0015]
In addition, the power generation device other than the master unit also has a function of determining an abnormality in the power system, and when each of the power generation units determines the result of the disturbance generated by the master unit, In addition, the determination result of the power generation device other than the master device is notified to the master device, and in the event of an abnormality, a power generation stop command is output from the master device to the power generation device other than the master device.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the embodiment of the present invention will be described in detail by taking the case of photovoltaic power generation as an example.
[0017]
As shown in FIG. 1, the present embodiment is a system in which a solar cell 10 that performs solar power generation and a power conditioner 12 that controls the output of the solar cell 10 are connected in parallel to a power company system. The power conditioner 12 is provided with a master / slave selector switch 14 and an independent operation detection signal input / output terminal 16, and each power conditioner 12 actively generates a disturbance by operating the master / slave selector switch 14. It can be used for either a master machine having a function to perform this function, or a slave machine to which a power generation stop command is input from the independent operation detection signal input / output terminal 16 when an abnormality is detected in the master machine.
[0018]
In the first embodiment of the present invention, the master / slave selector switch 14 of each power conditioner 12 is set as shown in FIG. 2, and the isolated operation detection signal input / output terminal 16 is also connected as shown in FIG. Yes.
[0019]
Further, as shown in FIG. 3, a power conditioner (referred to as a master (selection) machine) in which the master / slave changeover switch 14 is set to the master side internally introduces disturbances such as frequency fluctuations for active islanding detection. The remaining power conditioner (referred to as a “slave (selection) machine”) including both a function that occurs at a fixed period with a clock and a function that determines an abnormality in the power system, with the master / slave selector switch 14 set to the slave side. Is simply a power generation stop command from the master machine.
[0020]
In the first embodiment, only the master machine actively generates a disturbance and determines the abnormality of the power system at that time. All the remaining slave units stop power generation in response to a power generation stop command input from the master unit.
[0021]
In the present embodiment, since only the master machine has an active islanding detection function, there is no fear of mutual interference between the power generation apparatuses.
[0022]
On the other hand, in the second embodiment of the present invention, when only the determination function is provided to the slave machine, the result of the disturbance generated by the master machine is determined by each power generator, and an abnormality is recognized in the power system. Is to stop power generation according to the determination result of each power generator.
[0023]
In the present embodiment, there is no need to give a signal for stopping the function of the slave machine from the master machine to the slave machine when the isolated operation is detected, and the wiring between the master machine and the slave machine can be omitted.
[0024]
Next, in a third embodiment of the present invention, the timing at which the master machine generates a disturbance is notified to other slave machines. As a result, erroneous determination due to external disturbance can be prevented.
[0025]
Next, in the fourth embodiment of the present invention, the determination result of the power generators operating in parallel is notified to the master machine, and when abnormal, the master machine outputs a power generation stop command to each power generator. .
[0026]
In this case, for example, an additional function such as “match all machines”, “majority decision”, “stop even when one unit detects an abnormality”, and the like, enables more stable determination.
[0027]
In the above description, the number of master units is one. However, if the level (number) of mutual interference is small when multiple units implement the active detection method, the number of units below that number is determined. It may be handled as a master machine.
[0028]
In addition, in the said description, although this invention was applied to the solar energy power generation apparatus using a solar cell, the application object of this invention is not limited to this.
[0029]
【The invention's effect】
According to the present invention, since only the master machine generates a disturbance due to the active detection method, there is no malfunction due to mutual interference. Furthermore, since the amount of disturbance in the private facility by the power generation device is small, stable power supply can be achieved without degrading the quality of power due to the detection function.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an entire configuration of a natural energy power generation apparatus for system linkage according to the present invention. FIG. 2 is a master / slave selector switch and an independent operation detection signal input / output in a first embodiment of the present invention. FIG. 3 is a rear view of the inverter showing an example of the terminal connection state. FIG. 3 is a table comparing the functions of the master selector and the slave selector of the first embodiment.
DESCRIPTION OF SYMBOLS 10 ... Solar cell 12 ... Power conditioner 14 ... Master / slave switch 16 ... Single operation detection signal input / output terminal

Claims (3)

When operating a plurality of power generation devices that use natural energy as an energy source in conjunction with a power system in parallel with each other, the power system abnormality is actively monitored to prevent independent operation of the power generation device. In the system linkage method of the natural energy power generation apparatus as described above,
Only a part of the power generation apparatus is a master machine having a function of actively generating a disturbance to detect an abnormality of the power system and a function of determining an abnormality of the power system ,
A system linkage method for a natural energy power generator , wherein a power generation stop command is output to a power generator other than the master machine when an abnormality is detected in the master machine . In claim 1 , the power generation device other than the master machine is further provided with a function of determining an abnormality of the power system, and the power generation apparatus other than the master machine is notified of the timing at which the master machine generates a disturbance . A system linkage method for a natural energy power generation apparatus, wherein the result of disturbance generated by the master machine is determined by each power generation apparatus, and power generation is stopped when an abnormality is detected. The power generation device other than the master unit according to claim 1 further has a function of determining an abnormality of the power system, and the result of the disturbance generated by the master unit is determined by each power generation unit to detect an abnormality. The power generation is stopped and the determination result of the power generation device other than the master device is notified to the master device, and in the event of an abnormality, a power generation stop command is output from the master device to the power generation device other than the master device. A system linkage method for a natural energy power generation apparatus.

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