JP7154181B2 - Power generation system and its load input method - Google Patents

Description

The present invention provides a generator that is rotationally driven by an engine to generate power, a power load breaker that can parallelize a plurality of power loads on the user side with respect to the generator, and a state in which the engine is driven. A power load application process is executed to switch the power load breaker from the parallel state to the parallel state and apply the power load to the generator so that the output voltage of the generator is maintained at a specified voltage. Stores a power generation control unit that executes engine output control to control the output of the engine, and a load input rate that is a ratio of a rated load that can be input to the engine determined according to the elapsed time from the start of the engine. The present invention relates to a power generation system having a storage unit for storing data, and a method of applying a load to the power generation system.

2. Description of the Related Art In a facility provided with a power load such as an electric device, the received power of a reference voltage (eg, 6600 V) and a reference frequency (eg, 60 Hz) received from a commercial power system is normally supplied to the power load. In some cases, the facility is provided with a power generation system such as a cogeneration system that generates power by connecting to a commercial power system and can supply the power generated at the reference voltage and the reference frequency to the power load.
In such a power generation system, during a power outage when the power supply from the commercial power system is stopped, the generator is disconnected from the commercial power system, and the engine that drives the generator is started to operate the generator in a self-sustained manner. At the stage when the power generation voltage of the generator has been established and stable power generation has become possible, a part or all of the specific load to be supplied during a power failure is put into the generator, and the specific load is supplied. A device configured to continue power feeding is known (see Patent Document 1, for example).
In the power generation system, especially in the case of a gas engine that uses city gas as fuel, even if the load is less than the rated load, if an excessive load is applied at once, the engine cannot follow the sudden change in the load, resulting in unstable operation. and may stall.
For this reason, for example, as shown in FIG. 4, the load application relationship between the elapsed time from the start of the engine and the load application rate, which is the load application rate with respect to the rated load, is stored in the storage unit of the control device. Loading into the engine is made based on the relationship. In particular, the ratio of the load that can be applied first after starting the engine is defined as the initial load application rate. there is

Japanese Patent Application Laid-Open No. 2007-006595

In the engine related to the above power generation system, a fixed value is usually set for each model as the ratio of the initial load application rate to the rated load, but the load that can be applied immediately after starting the engine is However, current power generation systems take these factors into account. There was room for improvement.

The present invention has been made with a focus on this point, and its object is to provide a power generation system in which a generator is rotationally driven by an engine, in which the power load applied to the generator at the time of a power failure or the like is more in line with the actual situation. The object is to provide a technology capable of stabilizing engine operation and more effectively suppressing an increase in exhaust emissions, a stall, and the like.

The power generation system for achieving the above purpose is
a generator that is rotationally driven by an engine to generate power;
a power load breaker capable of disconnecting and paralleling a plurality of power loads on the user side with respect to the generator;
A power load application process is executed to apply the power load to the generator by switching the power load breaker from the parallel state to the parallel state while the engine is running, and the output voltage of the generator increases. A power generation control unit that executes engine output control to control the output of the engine so that it is maintained at a specified voltage; A power generation system having a storage unit that stores a load input rate, which is a ratio, characterized by:
The storage unit stores the power consumption of each power load,
The load application stored in the storage unit based on at least one of an ambient environment state index indicating the current state of the surrounding environment of the engine and an operating state index indicating the current operating state of the engine. a corrected load throwing rate deriving unit for deriving a corrected load throwing rate in which the rate is corrected;
Next, the sum of the power consumption of the power loads in the parallel state is equal to or less than the integrated value of the current corrected load input rate derived by the corrected load input rate derivation unit and the rated load of the engine. and a power load determination unit that determines, from among the plurality of power loads, the power load to be shifted from the parallel-off state to the parallel state next.

The load input method of the power generation system to achieve the above purpose is as follows.
A power generator that is rotationally driven by an engine to generate power, a power load breaker that can disconnect and parallel a plurality of power loads on the user side to the power generator, and a power load breaker that breaks the power load while the engine is running. switch the generator from the parallel state to the parallel state and execute power load input processing for inputting the power load to the generator, and outputting the engine so that the output voltage of the generator is maintained at a specified voltage. and a storage unit that stores a load input rate that is a ratio of the rated load that can be input to the engine determined according to the elapsed time from the start of the engine. A load input method for a power generation system comprising:
The storage unit stores the power consumption of each power load,
The method stored in the storage unit based on at least one of a current ambient environment condition index of the engine or a current operating condition index of the engine that affects combustion air taken into the engine. Corrected load input rate derivation processing for deriving a corrected load input rate obtained by correcting the load input rate;
Next, the sum of the power consumption of the power loads in the parallel state is equal to or less than the integrated value of the current corrected load input rate derived in the corrected load input rate deriving process and the rated load of the engine. and a power load determination process for determining, from among the plurality of power loads, the power load to be shifted from the parallel-off state to the parallel state next.

According to the above characteristic configuration, the load throwing rate, which was conventionally determined as a fixed value, is replaced by the corrected load throwing rate deriving unit, which is an ambient environment state index indicating the state of the surrounding environment of the engine at the present time, or Based on at least one of the operating state indicators indicating the operating state of the engine, the load rate is corrected to derive the corrected load rate. can be derived as a corrected load input rate.
Further, the power load determining unit determines the power consumption among the plurality of power loads so that the sum of the power consumption of the next power load in parallel state is equal to or less than the integrated value of the corrected load input rate and the rated load of the engine. By determining the power load to be shifted from the parallel state to the parallel state next from the parallel state, it is possible to input the power load that will be in the parallel state next according to the surrounding environment state and the operating state at the present time. can be stabilized, an increase in exhaust emissions and a power generation system that can effectively suppress stalls can be realized.

A further characteristic configuration of the power generation system is
An intake air temperature measuring unit that measures the temperature of intake air taken into the engine,
The corrected load throwing rate derivation section uses the intake air temperature measured by the intake air temperature measuring section as the ambient environment state index, and sets the corrected load throwing rate to a lower value as the intake air temperature rises.

According to the above characteristic configuration, the intake air temperature measured by the intake air temperature measuring unit is used as the ambient environment condition index, and the higher the intake air temperature, the lower the corrected load input rate. volume expands, the intake amount of fresh air in a substantial sense decreases, and the load injection rate in a substantial sense decreases, which can be reflected in the corrected load injection rate.

A further characteristic configuration of the power generation system is
An oil temperature measurement unit that measures the oil temperature, which is the temperature of the engine oil of the engine,
The corrected load throwing rate derivation section uses the oil temperature measured by the oil temperature measuring section as the operating state index, and the lower the oil temperature, the lower the corrected load throwing rate.

According to the above characteristic configuration, the oil temperature measured by the oil temperature measuring unit is used as the operating state index, and the lower the oil temperature, the lower the corrected load input rate. is not progressing, the operating state is unstable, and the decrease in the load throwing rate in a substantial sense can be reflected as the corrected load throwing rate.

A further characteristic configuration of the power generation system is
The storage unit stores the importance of each of the plurality of power loads,
Next, the power load determination unit calculates the power consumption of the power load in the parallel state with the current corrected load input rate derived by the corrected load input rate deriving unit and the rated load of the engine. on the premise that the integrated value of less than or equal to is satisfied, the power loads to be shifted from the parallel-off state to the parallel state next from the plurality of power loads are selected and determined in descending order of importance. at the point.

Among power loads, there are critical loads that are greatly affected when the power supply is interrupted.
According to the above characteristic configuration, the power loads to be shifted from the parallel state to the parallel state are selected in descending order of importance. Since it is executed on the premise that it satisfies the condition that it is less than or equal to the integrated value of the current corrected load injection rate derived by the corrected load injection rate derivation section and the rated load of the engine, stable operation of the engine is maintained and the engine stalls. can be effectively suppressed, and power can be supplied preferentially to important loads.

1 is a schematic configuration diagram of a power generation system according to an embodiment; FIG. FIG. 4 is a processing flow diagram of power generation control of the power generation system at the time of a power failure; FIG. 10 is a graph showing the tendency of correction of the corrected load input rate; FIG. 4 is a graph showing the elapsed time from engine start and the load input rate;

The power generation system 100 according to the embodiment of the present invention is a power generation system in which the generator 10b is rotationally driven by the engine 10a. The present invention relates to a system capable of stabilizing the operation of the engine and more effectively suppressing an increase in exhaust emissions, a stall, and the like.
A power generation system 100 according to this embodiment will be described below with reference to FIGS.

The power generation system 100 shown in FIG. 1 is installed in a facility such as a business office having a power load F that consumes the received power received from the commercial power system 1, and a power failure occurs in which power reception from the commercial power system 1 stops. It is configured as a system that supplies the power generated by the power generation device 10 to a plurality of power loads F when the power is generated. Received power received from the commercial power system 1 is supplied to the power line 3 . The received power is supplied to the power load F connected to the power line 9 via the third power load breaker K3, the transformer 20, the fourth power load breaker K4, and the like.
The power load F is a part of the total power load of the facility, such as emergency equipment such as compressors, pumps, elevators, and medical equipment. include. A power load power consumption meter 5 for measuring the power consumption of the power load F is provided at the connection of the power load F to the power line 9 .

The power generation system 100 includes a power generation device 10 and a power generation control device 15 (an example of a power generation control unit) that controls the operation of the power generation device 10 . The power generator 10 is configured to be able to supply the power load F with generated power having the same reference voltage (eg, 6600 V) and reference frequency (eg, 60 Hz) as the power received from the commercial power system 1 . Furthermore, the power generator 10 is configured as a cogeneration system that generates heat as it generates power.

The power generator 10 is configured as a general power generator that generates power by driving the generator 10b with the engine 10a and outputs the generated power. Although not shown, the power generator 10 includes a power converter that converts the power generated by the generator 10b into a reference voltage and a reference frequency, and a starter motor that starts the engine 10a using the power stored in the battery. It is The power generation control device 15 can independently start the engine 10a by the starter motor even in a state where there is no power supply from the outside. The engine output control is executed to control the output of the engine 10a so that the output voltage of the machine 10b is maintained at the specified voltage.
The output side of the power generation device 10 is connected to a power line 8 via a second power load breaker K2, and this power line 8 is connected to a power line 9 via a third power load breaker K3.
That is, the second power load breaker K2 and the third power load breaker K3 are configured to be able to parallel off the power load F to the generator 10b.

The power generation system 100 is provided with a grid connection protection relay 2 that measures the power reception voltage that the power line 3 receives from the commercial power system 1 . That is, the grid connection protection relay 2 functions as a power failure detection unit that monitors the measurement result of the received power voltage and detects a power failure that stops receiving power from the commercial power system 1 from the result.
On the other hand, the power generation control device 15 switches the first power load breaker K1 to the parallel-off state and switches the first power load breaker K1 to the parallel-off state at the time of a power failure when the power failure is detected by the measurement result of the grid connection protection relay 2, and the commercial power system is switched to the commercial power system. 1 and the power line 3 is disconnected from the generator 10b, the second power load breaker K2 and the third power load breaker K3 are switched from the parallel state to the parallel state while the engine 10a is started. A power load input process for inputting the power load F is executed. Note that, like this power load F, the power load that is applied to the generator 10b after the engine 10a is started may be called an initial load.

Now, as described above, when an electric load F is applied, especially in a gas engine fueled by city gas, if an excessive load is applied all at once even if the load is less than the rated load, the load may suddenly change. The engine may not be able to keep up with the change, and the operation may become unstable or stall.
For this reason, for example, as shown in FIG. 4, the load application relationship between the elapsed time from the start of the engine 10a and the load application rate, which is the load application rate with respect to the rated load, is stored in the storage unit M of the controller C. there is Then, the load is applied to the engine 10a in the storage unit M based on the load application relationship. For example, when the first elapsed time t1 has elapsed from the start of the engine 10a, the power load F is controlled so that it is equal to or less than the partial load obtained by multiplying the rated load by the initial load application rate.

The appropriate value of the load input rate described above is an ambient environment state index (for example, intake air temperature) indicating the state of the surrounding environment at the present time of the engine 10a, or an operating state index indicating the present operating state of the engine 10a (for example, Warm state: Fluctuates based on the temperature of the engine oil (hereinafter abbreviated as oil temperature).
Therefore, in the power generation system 100 in this embodiment, an intake air temperature sensor T1 (an example of an intake air temperature measuring unit) that measures the temperature of intake air taken into the engine 10a is provided, and an oil pan (not shown) of the engine 10a is provided. ) is provided with an oil temperature sensor T2 (an example of an oil temperature measuring unit) for measuring the oil temperature. Furthermore, as a control device C configured in a form in which software and hardware cooperate, based on the intake air temperature measured by the intake air temperature sensor T1 and the oil temperature measured by the oil temperature sensor T2, The sum of the power consumption of the corrected load throwing rate derivation unit C1 that derives the corrected load throwing rate by correcting the load throwing rate stored in M and the power consumption of the power load F that is next in parallel state is the corrected load throwing rate derivation. Electric power to shift from the parallel state to the parallel state next from among the plurality of power loads F so that the current corrected load input rate derived in the part C1 and the rated load of the engine 10a are equal to or less than the integrated value. A power load determination unit C2 that determines the load F, and a power load input unit C3 that inputs the power load determined by the power load determination unit C2.

To add an explanation, as shown in the graph of FIG. 3 showing the tendency of correction of the corrected load throwing rate, the corrected load throwing rate derivation section C1 increases the corrected load as the intake air temperature measured by the intake air temperature sensor T1 increases. The input rate is set to a low value, and the lower the oil temperature measured by the oil temperature sensor T2, the lower the corrected load input rate.
Although not shown in FIG. 3, the correction factor in each of the area where the correction is performed to decrease the load throwing rate and the area where the correction is made to increase the load throwing rate in FIG. It shall vary stepwise or continuously according to the oil temperature and shall not be a uniform correction factor.

For example, at the time of a power failure, the power load determination unit C2 determines that the sum of the power consumption of the next parallel power load F is the sum of the current corrected load input rate and the rated load of the engine 10a. By determining the power load F to be shifted from the parallel state to the parallel state next from among the plurality of power loads F so that the power consumption is the maximum at the value below the value, for more power loads F Execute control to supply power.

Furthermore, an explanation will be added regarding the determination of the power load F to be shifted from the parallel-off state to the parallel state by the power load determining unit C2.
As the power loads F, there are important loads that have a large impact when stopped and other normal loads.
Next, the power load determining unit C2 calculates the sum of the power consumption of the power loads F in parallel state by combining the current corrected load input rate derived by the corrected load input rate deriving unit C1 and the rated load of the engine 10a. On the premise that the condition that the integrated value of is less than or equal to .

Next, a series of control flows relating to power load input processing during a power failure executed by the power generation system 100 described so far will be described with reference to FIG. 2 .
When a power failure is detected by the measurement result of the grid connection protection relay 2 (yes side of step #01), the power generation control device 15 operates the first power load breaker K1 and the second power load breaker K2. In a state in which the power load F is disconnected from the generator 10b by switching to the parallel-off state (non-energized state), the starter motor is operated by the stored electric power to independently start the engine 10a (step #02). As a result, the rotation speed of the engine 10a increases, and accordingly the generated voltage of the generator 10b rotationally driven by the engine 10a increases.

Next, when the power generation control device 15 determines that the rotation speed of the engine 10a has reached the rated rotation speed and accordingly the voltage generated by the generator 10b has reached the reference voltage and has been established (step #03 yes side), the corrected load throwing rate derivation unit C1 determines whether or not the engine 10a is in the driving state from the measurement result of the rotation speed measurement sensor S1, for example, and also detects the intake air temperature sensor T1 and the oil temperature sensor T2 at that time. is obtained, and based on the intake air temperature measured by the intake air temperature sensor T1 and the oil temperature measured by the oil temperature sensor T2, the corrected load injection rate stored in the storage unit M is corrected. A corrected load input rate deriving process for deriving a rate is executed (step #04).
Further, the power load determination unit C2 calculates the sum of the power consumption of the power loads F in the next parallel state as follows: A power load determination process is executed to determine the power load F to be shifted from the parallel state to the parallel state next from among the plurality of power loads F so that the integrated value with the rated load or less is determined (step #05).
The power generation control device 15 switches the second power load breaker K2 and the third power load breaker K3 from the parallel state to the parallel state (energized state), and the power load application unit C3 causes the power load determination unit C2 to The fourth power load breaker K4 corresponding to the power load F to be shifted from the parallel-off state to the parallel state is switched from the parallel-off state to the parallel state (energized state), and the power load application process is executed ( step #06).
The processes of steps #04 to #06 are continuously executed until the engine 10a reaches the rated load or a predetermined time elapses from the start of the engine 10a (step #07).
[Another embodiment]
(1) In the above embodiment, an example was shown in which the engine 10a is started and various controls are executed during a power failure. can be driven even in the normal time.

(2) In the above embodiment, the power generation system 100 uses an ambient environment state index (for example, intake air temperature) indicating the current state of the ambient environment of the engine 10a, or an operating state index indicating the current operating state of the engine 10a. (For example, the configuration for deriving the corrected load input rate based on both the temperature of the engine oil (hereinafter abbreviated as oil temperature)) has been shown.
However, the corrected load input rate may be derived based on either the ambient environment state index or the driving state index.

(3) Humidity can also be used as the periodic environmental condition index. In this case, the corrected load input rate derivation section C1 determines that the higher the humidity, the higher the specific heat of the intake air, the slower the combustion in the combustion chamber, and the lower the shaft output. Therefore, the higher the humidity, the lower the corrected load input rate.

It should be noted that the configurations disclosed in the above embodiments (including other embodiments, the same shall apply hereinafter) can be applied in combination with configurations disclosed in other embodiments as long as there is no contradiction. The embodiments disclosed in this specification are exemplifications, and the embodiments of the present invention are not limited thereto, and can be modified as appropriate without departing from the object of the present invention.

The power generation system of the present invention is a power generation system in which a generator is rotationally driven by an engine. It can be effectively used as a power generation system that can more effectively suppress increases in emissions, stalls, and the like.

10: Power generation device 10a: Engine 10b: Generator 15: Power generation control device 100: Power generation system C: Control device C1: Corrected load input rate derivation unit C2: Power load determination unit F: Power load M: Storage unit S1: Rotational speed Measurement sensor T1: intake air temperature sensor T2: oil temperature sensor

Claims (5)

a generator that is rotationally driven by an engine to generate power;
a power load breaker capable of disconnecting and paralleling a plurality of power loads on the user side with respect to the generator;
A power load application process is executed to apply the power load to the generator by switching the power load breaker from the parallel state to the parallel state while the engine is running, and the output voltage of the generator increases. A power generation control unit that executes engine output control to control the output of the engine so that it is maintained at a specified voltage; A power generation system having a storage unit that stores a load input rate that is a ratio,
The storage unit stores the power consumption of each power load,
The load application stored in the storage unit based on at least one of an ambient environment state index indicating the current state of the surrounding environment of the engine and an operating state index indicating the current operating state of the engine. a corrected load throwing rate deriving unit for deriving a corrected load throwing rate in which the rate is corrected;
Next, the sum of the power consumption of the power loads in the parallel state is equal to or less than the integrated value of the current corrected load input rate derived by the corrected load input rate derivation unit and the rated load of the engine. a power load determination unit that determines the power load to be shifted from the parallel-off state to the parallel state next from among the plurality of power loads so that the power load is as follows. An intake air temperature measuring unit that measures the temperature of intake air taken into the engine,
2. The corrected load application rate derivation unit uses the intake air temperature measured by the intake air temperature measurement unit as the ambient environment state index, and sets the corrected load application rate to a lower value as the intake air temperature increases. The power generation system described. An oil temperature measurement unit that measures the oil temperature, which is the temperature of the engine oil of the engine,
3. The corrected load throwing rate derivation unit uses the oil temperature measured by the oil temperature measuring unit as the operating state index, and sets the corrected load throwing rate to a lower value as the oil temperature decreases. The power generation system described. The storage unit stores the importance of each of the plurality of power loads,
The power load determination unit calculates the power consumption of the power load that will be in the next parallel state by multiplying the current corrected load input rate derived by the corrected load input rate deriving unit and the rated load of the engine. 4. On the premise that a condition of less than or equal to a value is satisfied, the power loads to be shifted next from the parallel-off state to the parallel state are selected from among the plurality of power loads and determined in descending order of importance. 4. The power generation system according to any one of 1 to 3. A power generator that is rotationally driven by an engine to generate power, a power load breaker that can disconnect and parallel a plurality of power loads on the user side to the power generator, and a power load breaker that breaks the power load while the engine is running. switch the generator from the parallel state to the parallel state and execute power load input processing for inputting the power load to the generator, and outputting the engine so that the output voltage of the generator is maintained at a specified voltage. and a storage unit that stores a load input rate that is a ratio of the rated load that can be input to the engine determined according to the elapsed time from the start of the engine. A load input method for a power generation system comprising:
The storage unit stores the power consumption of each power load,
The method stored in the storage unit based on at least one of a current ambient environment condition index of the engine or a current operating condition index of the engine that affects combustion air taken into the engine. Corrected load input rate derivation processing for deriving a corrected load input rate obtained by correcting the load input rate;
Next, the sum of the power consumption of the power loads in the parallel state is equal to or less than the integrated value of the current corrected load input rate derived in the corrected load input rate deriving process and the rated load of the engine. a power load determination process for determining, from among the plurality of power loads, the power load to be shifted from the parallel-off state to the parallel state next so that

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