JP6208613B2 - Power generation system - Google Patents

Description

  The present invention relates to a power generation system, in particular, combined with a power generation facility that uses renewable energy such as sunlight while stably supplying power to an important load that needs to be operated even in an emergency such as a power failure. Thus, the present invention relates to a power generation system that is intended to save energy or extend operating time.

  There are cases where a renewable energy power generation facility that generates power using renewable energy such as sunlight, wind power, and geothermal heat is provided in a consumption facility that consumes power, such as an office, a store, or a home. There is a power purchase system in which a power company purchases the power generated by a renewable energy power generation facility. When using this system, all the power generated by the renewable energy power generation facility is sold to the power company, and it is stored in its own facility. In general, power consumption is received from an electric power company.

  By the way, when power transmission from an electric power company such as a power outage stops, there is a case where it is desired to use the electric power generated by the renewable energy power generation facility that has been sold in its own consumption facility. As a technique that can be used in such a case, for example, Patent Document 1 discloses a battery such as a solar cell or a fuel cell, an inverter that converts DC output power from the battery into AC power, and is grid-connected, There is disclosed a home power generation system including a control unit that controls a preset power supply location in a home when commercial power supplied from the system stops. According to the household power generation system, when there is a power failure in the power distribution facility on the power company side, control is performed so as to stop selling power from the inverter to the power distribution facility, and the inverter is connected to the set power supply location in the home. It is said that there is an effect that it can be used without the need to reconnect the electrical equipment to the dedicated outlet.

JP200415035

  With the technology described in Patent Document 1, the power that was normally sold can be consumed in the own facility in the event of an emergency such as a power failure. However, renewable energy power generation facilities are environment-dependent power generation facilities whose output fluctuates depending on the environment such as the amount of solar radiation. Therefore, with such environment-dependent power generation facilities alone, the necessary minimum that must be secured even in an emergency. There is a risk that power cannot be secured. In addition to the environment-dependent power generation facilities, such fears may be caused by installing power generation facilities that are not dependent on the environment (environment-independent power generation facilities) that generate electricity using fuel that is stably supplied or stored. This can be avoided by a power generation system that operates the facility independently. According to a power generation system that operates an autonomous power generation facility such as a solar cell and an environment-independent power generation facility such as a cogeneration system, even if the output from the environment-dependent power generation facility becomes zero, The necessary minimum power can be secured by the environment-independent power generation facility.

  By the way, when the most efficient operation of a power generation system that operates an environment-dependent power generation facility and an environment-independent power generation facility in a self-sustained operation is the consumption consumed by the total generated power and load of both power generation facilities. It is preferable to balance power. Also, in order to save fuel consumed by environment-independent power generation facilities, the contribution of environment-dependent power generation facilities is made as much as possible in the total generated power, and the contribution of environment-independent power generation facilities is made as small as possible. It is preferable. In other words, it is possible to control the output of the environment-independent power generation facility so that the power supply from the environment-independent power generation facility has priority and the power supply from the environment-independent power generation facility supplements the shortage that does not reach power consumption. preferable.

  However, when the environment independent power generation facility is controlled as described above, when the output of the environment dependent power generation facility exceeds the power consumption, the output of the environment independent power generation facility is controlled to zero. When the output of the environment-independent power generation facility becomes zero, there is a possibility that the environment-independent power generation facility may be damaged due to a reverse power flow from the environment-dependent power generation facility. Conventionally, a countermeasure using a tidal current detector has been taken as a countermeasure against the reverse power flow. The tidal current detector is a detector that detects the direction of power at the detection point of the power line (forward power or reverse power (reverse power flow)) and outputs a signal. It is installed at the output stage of the environment-independent power generation equipment. When reverse power (reverse power flow) is detected, the output of the environment-dependent power generation facility can be cut off to protect the environment-independent power generation facility. However, when a reverse power flow is detected by a power flow detector, power flows back to the output stage of the environment-independent power generation facility, although it is small, and the reverse power flow to such an output stage is The present inventors have recognized that a small-scale power generation facility in which the output capacity of the facility is not so large can cause a failure with a high probability, and some countermeasure is necessary.

  The objective of this invention is providing the technique which implement | achieves efficient operation | movement in the electric power generation system which uses an environment dependent power generation equipment and an environment independent power generation equipment together. Another object of the present invention is to provide a technology capable of preventing failure of the environment-independent power generation facility even when the environment-independent power generation facility is a small-scale power generation facility.

  In addition, when the output power of the environment-dependent power generation facility exceeds the power consumed by the load, that is, when there is surplus power, it is preferable to utilize the surplus power without wasting it. In this case, surplus power should be preferentially supplied to loads that must be kept in operation even in an emergency (hereinafter referred to as “important loads”). When there is a surplus in the total generated power, it is preferable to supply power to a load other than the important load (hereinafter referred to as “normal load”).

  An object of the present invention is to provide a power generation system that can preferentially supply power to an important load and supply the surplus power to a normal load when there is surplus power.

  Furthermore, when the output of the environment-dependent power generation equipment fluctuates in the power generation system as described above, it is necessary to control the distribution status to be changed appropriately according to the situation, and it is consumed by the environment-independent power generation equipment. It is preferable to control the fuel as little as possible.

  An object of the present invention is to provide a control technique that can cope with output fluctuations of an environment-dependent power generation facility and suppress fuel consumption in the environment-independent power generation facility in the power generation system described above.

  In order to solve the above-described problems, in the first aspect of the present invention, power generation is performed by the first power generation facility in which the amount of power generation varies with the variation in input energy, and the fuel that is stably supplied or stored. A second power generation facility, a first power distribution system that guarantees the supply of power up to the guaranteed power value, and a second power distribution system in which the power supply is stopped depending on the situation, A power distribution system that distributes power received from the power generation facility, wherein the output of the second power generation facility is controlled so that the power generated by the power generation facility and the power distribution of the power distribution facility are balanced. Provided is a power generation system in which power supply control from the first power generation facility or power distribution control to the second power distribution system is performed according to the output power of the first power generation facility or the second power generation facility.

  According to the power generation system described above, the output of the second power generation facility is controlled so that the generated power of the power generation facility and the distribution power of the power distribution facility are balanced, and according to the output power of the second power generation facility, Since power supply control from the first power generation facility or power distribution control to the second power distribution system is performed, the power generation system uses both the environment-dependent first power generation facility and the environment-independent second power generation facility. Thus, efficient operation can be realized.

  Specifically, when the output power of the second power generation facility falls below a minimum set power value, the supply of power from the first power generation facility can be turned off. Thereby, even if the environment-independent second power generation facility is a small-scale power generation facility, a failure of the second power generation facility can be prevented.

  In addition, when the output power of the second power generation facility is equal to or lower than the first set power value, power distribution to the second power distribution system is turned on, and the output power of the second power generation facility is larger than the first set power value When the power value is equal to or higher than the second set power value, power distribution to the second power distribution system can be turned off. As a result, power is preferentially supplied to the important load connected to the first power distribution system, and when there is surplus power, the surplus power can be supplied to the normal load connected to the second power distribution system. It becomes possible.

  Further, when the output power of the second power generation facility is equal to or less than a third set power value, the power distribution to the second power distribution system is turned on, and the output power of the second power generation facility and the power distribution to the first power distribution system When the difference in power is equal to or greater than the fourth set power value, power distribution to the second power distribution system can be turned off. Accordingly, it is possible to cope with output fluctuations of the environment-dependent first power generation facility and to suppress fuel consumption in the environment-independent second power generation facility.

  When the output power of the first power generation facility is equal to or greater than a fifth set power value, power distribution to the second power distribution system is turned on, and the output power of the first power generation facility is smaller than the fifth set power value When it is less than or equal to the sixth set power value, power distribution to the second power distribution system can be turned off. As a result, the output of the environment-dependent first power generation facility is directly measured, and when the first power generation facility is sufficiently operating, it is considered that there is surplus power and this is connected to the second distribution system. If normal power is supplied and there is no surplus power, the power supply to the normal load is cut off, and control is given to give priority to the power supply to the important load connected to the first distribution system. Can do.

  The power distribution to the second power distribution system is maintained in the on state until the condition for changing from the on state to the off state is satisfied, and maintained in the off state until the condition for changing from the off state to the on state is satisfied. Can be controlled. Further, the maximum value of the power that can be supplied from the second power generation facility can be set as the guaranteed power value. A solar power generation facility can be cited as the first power generation facility, and a gas cogeneration system can be cited as the second power generation facility.

1 is a block diagram showing an outline of a power generation system 100. FIG. 1 is a block diagram showing an outline of a power generation system 200. FIG. 2 is a block diagram showing an outline of a power generation system 300. FIG.

(Embodiment 1)
FIG. 1 is a block diagram showing an outline of the power generation system 100. The power generation system 100 includes a power generation facility 110, a power distribution facility 120, and a control unit 130. The power generation facility 110 is a power generation facility that can supply power even when power transmission from a power company such as a power failure stops. The power generation facility 110 includes a first power generation facility in which the amount of power generation fluctuates with a change in input energy, and a second power generation facility that generates power using fuel that is stably supplied or stored. The power generation facility 110 causes the first power generation facility and the second power generation facility to operate independently. The power distribution facility 120 distributes the power received from the power generation facility 110. The distribution facility 120 includes a first distribution system 122 that guarantees the supply of power up to the guaranteed power value, and a second distribution system 124 that stops the supply of power depending on the situation.

  The power generation facility 110 includes a solar cell panel 112, an inverter 114, a cogeneration system 116, and a UPR 118. The output of the inverter 114 includes a first switch SW1, and the output of the cogeneration system 116 includes a first power measurement point A1. Is provided.

  The solar cell panel 112 and the inverter 114 are an example of a first power generation facility in which the amount of power generation varies as the input energy varies. The solar cell panel 112 receives sunlight, which is renewable energy, and generates power, and the inverter 114 converts the DC power generated by the solar cell panel 112 into AC power. The output of the solar cell panel 112 varies according to the amount of solar radiation. Other examples of the first power generation facility in which the power generation amount fluctuates with the fluctuation of input energy include wind power generation and geothermal power generation.

  The cogeneration system 116 is an example of a second power generation facility that generates power using fuel that is stably supplied or stored. The cogeneration system 116 includes a heat generation unit together with the power generation unit, and here, the power generation unit is used. In the case of a gas cogeneration system, city gas is stably supplied as fuel, and normally even in the event of a power failure, fuel is stably supplied. As another example of the second power generation facility that generates power using fuel that is stably supplied or stored, a diesel generator can be cited.

  The UPR 118 is a shortage power relay. The UPR 118 receives the power measurement value at the first power measurement point A1, and controls on / off of the first switch SW1. The UPR 118 is a relay that detects whether or not the output power is insufficient as compared with a preset power value, and generates a cutoff signal when the output power is insufficient. In the present invention, it functions as a control means for controlling on / off of the first switch SW1. When the minimum power value is set as the power value set in advance in the UPR 118, first control as described later becomes possible.

  The power distribution facility 120 includes a first power distribution system 122 and a second power distribution system 124. An important load 140 is connected to the first power distribution system 122 to guarantee supply of power up to the guaranteed power value. Since the load connected to the first power distribution system 122 is guaranteed to be supplied within the guaranteed power value even in an emergency in which power transmission from the power company stops, the first power distribution system 122 Connects an important load 140 that needs to be operated even during a power failure, such as in-hospital facilities necessary for life support.

  The power distribution of the second power distribution system 124 is stopped according to the situation. A normal load 150 that may be stopped in an emergency is connected to the second power distribution system 124. The second power distribution system 124 is provided with a second switch SW2, and the second power distribution system 124 can be shut off by turning off the second switch SW2. The control means 130 receives the power measurement value at the first power measurement point A1, and controls on / off of the second switch SW2.

  Below, control of the electric power generation system 100 is demonstrated. In principle, the power generation system 100 is controlled so that the generated power of the power generation facility 110 and the distribution power of the power distribution facility 120 are balanced. The distribution power varies depending on the load, and the output of the solar cell panel 112 varies depending on the amount of solar radiation. Therefore, the balance between the generated power and the distribution power is controlled by the output control of the cogeneration system 116. For example, when the power supplied to the load is 50 kW and the output from the solar cell panel 112 is 30 kW, the output of the cogeneration system 116 is controlled to be 20 kW. The output control of the cogeneration system 116 is automatically performed by the cogeneration system 116 by monitoring the output voltage. Since the generated power of the solar cell panel 112 is preferentially applied to the distribution power, the operation of the cogeneration system 116 is suppressed and energy saving can be achieved.

  As described above, the output of the cogeneration system 116 is controlled so that the generated power and the distributed power are balanced in principle. However, the supply control of power from the solar panel 112 is performed in response to system safety and load fluctuations. Alternatively, power distribution control to the second power distribution system 124 is performed. In this control, the output power of the cogeneration system 116 is monitored at the first power measurement point A1, and power supply control from the solar cell panel 112 or power distribution control to the second power distribution system 124 is performed according to the monitored power value. Is done.

  Specifically, when the output power of the cogeneration system 116 falls below the minimum set power value, the supply of power from the solar cell panel 112 is turned off (hereinafter referred to as “first control”). That is, the output power of the cogeneration system 116 is monitored at the first power measurement point A1, and it is determined by the UPR 118 whether or not the output power is less than or equal to the minimum set power value. When the power is less than or equal to the minimum set power value, the first switch SW1 is turned off to turn off the power supply from the solar cell panel 112.

  Such control is performed to protect the cogeneration system 116. That is, assuming that the output of the cogeneration system 116 is controlled so that the generated power and the distributed power are balanced, if the supply of power from the solar cell panel 112 exceeds the distributed power, the cogeneration system 116 The output power becomes zero. Generally, in an emergency power generation system used at the time of a power failure or the like, a cogeneration system having a small output is selected.

  In a small-capacity cogeneration system, there is a possibility of a failure even if a slight power reverse flow occurs. When the output power of the cogeneration system 116 becomes zero, the possibility of a failure due to the reverse flow increases. Therefore, when the output power of the cogeneration system 116 falls below the minimum set power value, the power supply from the solar cell panel 112 is turned off, and the minimum set power value before the output power becomes zero is obtained. When this is detected, the power supply from the solar cell panel 112 is turned off. Thereby, the failure of the cogeneration system 116 can be avoided reliably. The power generation system 100 according to the present embodiment uses the UPR 118, unlike the conventional technology in which a protection circuit is configured using a reverse power flow detector, and thus does not generate a reverse power flow and reliably protects the cogeneration system 116. be able to.

  Further, when the output power of the cogeneration system 116 is equal to or less than the first set power value, the power distribution to the second distribution system 124 is turned on, and the second setting in which the output power of the cogeneration system 116 is larger than the first set power value. When the power value is equal to or higher than the power value, the power distribution to the second power distribution system 124 is turned off (hereinafter referred to as “second control”). On / off of power distribution to the second power distribution system 124 is performed by the second switch SW2. Further, the output power of the cogeneration system 116 is monitored at the first power measurement point A1, and the control is performed by the control means 130.

  Such control is performed so that the surplus power from the solar cell panel 112 can be consumed even by the normal load 150. That is, if a relatively small value is set as the first set power value, the situation where the output power of the cogeneration system 116 is equal to or less than the first set power value, that is, the power supply from the solar cell panel 112 is relatively large, It can be said that the power generation capacity of the cogeneration system 116 has a margin. In such a situation, since the normal load 150 also has power to supply power, the power is also supplied to the normal load 150 by turning on SW2. The situation where the output power of the cogeneration system 116 is equal to or greater than the second set power value is a situation where the cogeneration system 116 is operated by consuming fuel while supplying power to the normal load 150. It is not preferable from the viewpoint of fuel saving. Therefore, the power supply to the normal load 150 is stopped by turning off SW2.

  The second control may be used together with the first control, or may be applied separately. When the second control is used in combination with the first control, the first set power value is larger than the minimum set power value. This is because the first control is used only as protection control for the cogeneration system 116, and when the second control is operating normally, the first control is not operated.

(Embodiment 2)
FIG. 2 is a block diagram showing an outline of the power generation system 200. The power generation system 200 is the power generation system except that the output power of the cogeneration system 116 is measured at the first power measurement point A1 and the distribution power of the first distribution system 122 is also measured at the second power measurement point A2. 100. The power measured at the second power measurement point A2 is the power supplied to the important load 140.

  Control of the power generation system 200 will be described below. Control similar to control 1 in the first embodiment can be executed in the power generation system 200.

  Further, in the power generation system 200, when the output power of the cogeneration system 116 is equal to or less than the third set power value, the power distribution to the second distribution system 124 is turned on, and the output power of the cogeneration system 116 and the first distribution system are turned on. When the difference between the distribution powers is equal to or greater than the fourth set power value, the distribution to the second distribution system 124 is turned off (hereinafter referred to as “third control”). On / off of power distribution to the second power distribution system 124 is performed by the second switch SW2. The output power of the cogeneration system 116 is monitored at the first power measurement point A1, and the distribution power to the first distribution system is monitored at the second power measurement point A2. Control is performed by the control means 130.

  Such control is performed so that the surplus power from the solar cell panel 112 can be consumed by the normal load 150 as well as the control 2. That is, if a relatively small value is set as the third set power value, the situation where the output power of the cogeneration system 116 is equal to or less than the third set power value, that is, the power supply from the solar panel 112 is relatively large, It can be said that the power generation capacity of the cogeneration system 116 has a margin. In such a situation, since the normal load 150 also has power to supply power, the power is also supplied to the normal load 150 by turning on SW2. On the other hand, the situation where the difference between the output power of the cogeneration system 116 and the distribution power to the first distribution system is equal to or greater than the fourth set power value is that the power that is equal to or greater than the fourth set power value among the output power of the cogeneration system 116. This means that the load is normally supplied to the load 150. This means that fuel corresponding to power equal to or higher than the fourth set power value is used for the normal load 150, which is not preferable from the viewpoint of fuel saving. Therefore, the power supply to the normal load 150 is stopped by turning off SW2.

  Note that the third control may be used together with the first control, or may be applied separately and independently. When the third control is used in combination with the first control, the third set power value is set to a value larger than the minimum set power value. This is because the first control is used only as protection control for the cogeneration system 116, and when the third control is operating normally, the first control is not operated.

(Embodiment 3)
FIG. 3 is a block diagram showing an outline of the power generation system 300. The power generation system 300, in addition to measuring the output power of the cogeneration system 116 at the first power measurement point A1, in addition to measuring the output power from the inverter 114 also at the third power measurement point A3, It is the same. The power measured at the third power measurement point A3 is the power supplied from the solar cell panel 112 and the inverter 114.

  Control of the power generation system 300 will be described below. Control similar to control 1 in the first embodiment can be executed in the power generation system 300.

  Further, in the power generation system 300, when the output power from the solar cell panel 112 and the inverter 114 is equal to or higher than the fifth set power value, the power distribution to the second power distribution system 124 is turned on, and the power from the solar cell panel 112 and the inverter 114 is turned on. When the output power is equal to or smaller than the sixth set power value smaller than the fifth set power value, the power distribution to the second power distribution system 124 is turned off (hereinafter referred to as “fourth control”). On / off of power distribution to the second power distribution system 124 is performed by the second switch SW2. The output power of the cogeneration system 116 is monitored at the first power measurement point A1, and the output power from the solar cell panel 112 and the inverter 114 is monitored at the third power measurement point A3. Control is performed by the control means 130.

  Such control is performed so that the surplus power from the solar cell panel 112 can be consumed by the normal load 150 as well as the control 2 and the control 3. That is, the fifth set power value is set as the power value at which the output power from the solar cell panel 112 and the inverter 114 is considered to be sufficiently large, and the output power from the solar cell panel 112 and the inverter 114 is considered to be insufficient. When the sixth set power value is set as the value, when it is considered that the solar panel 112 is sufficiently operated under strong sunshine, the output power from the solar panel 112 and the inverter 114 is turned on by turning on SW2. When power is supplied to the normal load 150, the sunlight is shaded, and it is considered that the operation of the solar cell panel 112 is not sufficient, the power supply to the normal load 150 is cut off by turning off SW2, and the power supply to the important load 140 is cut off. Priority can be given.

  The fourth control may be used together with the first control, or may be applied separately and independently. When the fourth control is used in combination with the first control, the sixth set power value is larger than the minimum set power value. This is because the first control is used only as protection control for the cogeneration system 116, and when the fourth control is operating normally, the first control is not operated.

  According to the power generation system 100, the power generation system 200, and the power generation system 300 described above, efficient operation can be realized, and failure of the cogeneration system 116 can be prevented. Further, when there is surplus power while preferentially supplying power to the important load 140, it is possible to supply surplus power to the normal load 150. Furthermore, fuel consumption in the cogeneration system 116 can be suppressed.

  In Control 2, Control 3 and Control 4, the on-state is maintained until the power distribution to the second power distribution system 124 satisfies the condition for switching from the on-state to the off-state, and the condition for switching from the off-state to the on-state is set. It may be controlled to maintain the off state until it is satisfied, that is, a hysteresis may be provided for on / off.

  In Embodiments 1, 2, and 3, it is preferable that the maximum value of the power that can be supplied by the cogeneration system 116 is a guaranteed power value. In this case, even in the worst case where power generation from the solar cell panel 112 is zero, the cogeneration system 116 can supply power to the important load 140 alone.

  DESCRIPTION OF SYMBOLS 100 ... Power generation system, 110 ... Power generation equipment, 112 ... Solar cell panel, 114 ... Inverter, 116 ... Cogeneration system, 118 ... UPR, 120 ... Power distribution equipment, 122 ... First power distribution system, 124 ... Second power distribution system, 130 ... Control means, 140 ... Important load, 150 ... Normal load, 200 ... Power generation system, 300 ... Power generation system, A1 ... First power measurement point, A2 ... Second power measurement point, A3 ... Third power measurement point, SW1 ... First switch, SW2... Second switch.

Claims (7)

A power generation facility having a first power generation facility in which the amount of power generation fluctuates in accordance with a change in input energy, and a second power generation facility that generates power using fuel that is stably supplied or stored, and
A power distribution facility having a first power distribution system that guarantees the supply of power up to a guaranteed power value and a second power distribution system that stops power supply depending on the situation, and that distributes the power received from the power generation facility When,
A power generation system comprising:
The output of the second power generation facility is controlled so that the generated power of the power generation facility and the distribution power of the power distribution facility are balanced,
In accordance with the output power of the first power generation facility or the second power generation facility, power supply control from the first power generation facility or power distribution control to the second power distribution system is performed ,
When the output power of the second power generation facility falls below a minimum set power value, the power supply from the first power generation facility is turned off.
Power generation system. When the output power of the second power generation facility is equal to or lower than the first set power value, the power distribution to the second power distribution system is turned on, and the output power of the second power generation facility is larger than the first set power value. If the set is not less than the power value, the power generation system according to claim 1 to turn off the power distribution to the second distribution system. When the output power of the second power generation facility is less than or equal to a third set power value, the power distribution to the second power distribution system is turned on, and the output power of the second power generation facility and the power distribution power to the first power distribution system If the difference is the fourth set or the power value, the power generation system according to claim 1 to turn off the power distribution to the second distribution system. When the output power of the first power generation facility is greater than or equal to a fifth set power value, power distribution to the second power distribution system is turned on, and the output power of the first power generation facility is smaller than the fifth set power value. If the setting is less than the power value, the power generation system according to claim 1 to turn off the power distribution to the second distribution system. Power distribution to the second power distribution system is controlled to maintain the on state until the condition for changing from the on state to the off state is satisfied, and to maintain the off state until the condition for changing from the off state to the on state is satisfied. The power generation system according to any one of claims 2 to 4 . The power generation system according to any one of claims 1 to 5 , wherein a maximum value of power that can be supplied from the second power generation facility is the guaranteed power value. The power generation system according to any one of claims 1 to 6, wherein the first power generation facility is a solar power generation facility, and the second power generation facility is a gas cogeneration system.

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