JP6119383B2 - Power supply system and power supply and demand adjustment method - Google Patents

Description

The present invention relates to a power supply system that is connected to a commercial system and includes a private power generator and supplies power together with the commercial system, and a power supply / demand adjustment method that adjusts an imbalance between power supply and demand.

Patent Documents 1 and 2 describe specific examples of a system including a private power generator that supplies power together with a commercial system to facilities that require power supply.
This type of system can reduce the burden of power supply from the commercial system when the commercial system is energized, and can operate the facility by supplying power from the private power generator during a power failure of the commercial system.

The power system with private generators (hereinafter also referred to as “private power system”) is connected to the large generator system of the power company when power is supplied from the commercial system. The balance of power supply and demand in the private power system is balanced by the adjustment capability of the large generator system.
On the other hand, when a commercial power failure occurs, the private power system is disconnected from the commercial system, and a single operation is performed to operate the private power generator in a closed area. The adjustment balances the supply and demand of electricity.

For this reason, when the power supply and demand becomes unbalanced at a level exceeding the allowable range of the generator during stand-alone operation, a trip occurs in which the protection circuit is activated and the generator is shut off. May lead to a complete power outage.
Immediately after the power failure of the commercial system, the power supply / demand difference in the private power system becomes large.After the power failure of the commercial system, how to resolve the situation where the power supply / demand difference is large is shifted to independent operation. It is important in completing stably. In order to eliminate this large power supply-demand difference, it is necessary to provide a private power system with, for example, a system stabilizing device as described in Patent Document 3 and a power storage means capable of charging and discharging. Conceivable. The system stabilizing device cuts off a predetermined facility due to a power failure of the commercial system, and is therefore effective in solving a state in which the demand for power greatly exceeds the supply of power.

Since the systems described in Patent Documents 1 and 2 are provided with power storage means, the power supply and demand can be adjusted using this power storage means when shifting to the single operation. Describes the specific method. In the method described in Patent Document 1, in a private power system, when the demand for power exceeds the supply, the power storage means discharges, and then the discharge is performed until the discharge amount of the power storage means becomes zero. It gradually decreases with the amount of change within the allowable range of the generator.

JP 2007-6595 A JP 2003-70165 A JP-A-8-322148

However, the method described in Patent Document 1 is not economical because a large-capacity power storage means is required because power supply and demand adjustment is performed mainly using only the power storage means without using the system stabilizing device.
And the main purpose of providing the power storage means is to adjust the receipt of power when shifting to the single operation to the last, and the power storage means is from the commercial system in the normal operation in which power is supplied from the commercial system. It does not reduce the burden of power supply. Accordingly, providing a large-capacity power storage means is not effective from the viewpoint of reducing the burden on the commercial system.

Further, Patent Document 1 does not assume that the power supply / demand balance is large due to a power failure in a commercial system, and that the supply is excessive.
When a power failure occurs in a commercial system, equipment may stop in a private power system due to a sudden change in voltage, resulting in excessive power supply. When a system stabilization device is installed, due to a power outage of the commercial system, the system stabilization device will systematically shut down multiple facilities, and the facility that is not scheduled to shut down may also be shut down. In such a power system, there may be a situation in which excessive power supply becomes significant.
If it is attempted to solve the state where the excessive power supply becomes remarkable only by the power storage means, it is necessary to employ the power storage means having a huge capacity, which is not realistic.

Here, since the generator has a BTG (Boiler Turbine Generation) system that can rapidly reduce the output (100% / min or more) in an emergency, excessive power supply is remarkable due to the adoption of the BTG generator. It is conceivable to eliminate the state of becoming.
However, since the output increase rate of the BTG generator is slow (for example, 3% / min), it is possible to stabilize the single operation mainly by adjusting the power supply / demand using the increase / decrease in the power supply after the single operation can be performed. Therefore, it is desirable to adopt a gas engine generator having a faster output increase rate (for example, 15% / min) than the BTG type generator. In addition, by adopting a gas engine generator that has a degree of freedom of adjustment compared to the BTG system in both increases and decreases in output, it is possible to reduce the amount of power supplied from the power company during normal operation. Note that the gas engine generator has an output reduction rate slower than that of the BTG generator, for example, 15% / min.

In addition, since the system stabilization device can select the facility to which power is to be supplied in the event of a power failure in the commercial system, providing the system stabilization device in a private power system is to supply power to facilities that should be prioritized for operation. It is preferable in that
The present invention has been made in view of such circumstances, and includes a power supply system that includes a gas engine generator and a system stabilizing device, and performs power supply and demand adjustment without using a large-capacity power storage unit, and power supply and demand adjustment. It aims to provide a method.

A power supply system according to the first invention that meets the above-described object includes a gas engine generator that supplies power to a plurality of facilities together with a commercial system, and a system stabilizing device that selectively cuts off the facility due to a power failure of the commercial system, A plurality of gas engine generators having a maximum output not less than 0.5 times and not more than 1.0 times the maximum output of the gas engine generator having the largest maximum output. Power storage means, and control means for adjusting an imbalance between power supply and demand caused by a power failure of the commercial system by selectively shutting off the gas engine generator and charging / discharging of the power storage means.

In the power supply system according to the first invention, the power storage means preferably includes a lithium ion battery.

A power supply and demand adjustment method according to the second invention that meets the above-described object includes a plurality of gas engine generators that supply power to a plurality of facilities together with a commercial system, and a system that selectively cuts off the facility due to a power failure of the commercial system A stabilization device and power storage means having a maximum output of 0.5 to 1.0 times the maximum output of the gas engine generator having the maximum maximum output are provided, and are caused by a power failure of the commercial system The power supply / demand imbalance is adjusted by selectively shutting off the gas engine generator and charging / discharging the power storage means.

In the power supply and demand adjustment method according to the second invention, it is preferable that the power storage means includes a lithium ion battery.

The power supply system according to the first invention and the power supply and demand adjustment method according to the second invention are 0.5 times to 1.0 times the maximum output of the gas engine generator having the largest maximum output. After providing power storage means with the maximum output, and roughly adjusting the power supply and demand imbalance caused by the power failure of the commercial system with the system stabilization device, selective shutoff of the gas engine generator and charging of the power storage means Make final adjustments by discharging.
Here, when the maximum output increases, the power storage means needs to increase the capacity in order to secure a predetermined charge / discharge time, and the capacity can also be suppressed by suppressing the maximum output.
Therefore, the power supply system according to the first invention and the power supply and demand adjustment method according to the second invention perform power supply and demand adjustment without using a large-capacity power storage means, and shift to a single operation. Can be performed stably.

(A), (B) is explanatory drawing which shows the state by which the electric power supply system which concerns on one embodiment of 1st invention was connected to the commercial system, and the state by which system | strain isolation | separation, respectively. It is a graph which shows the state of the electric power at the time of shifting to normal operation from independent operation. It is a flowchart which shows the power supply-and-demand adjustment method which concerns on one embodiment of 2nd invention. It is a flowchart which shows the same supply-and-demand adjustment method.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
As shown in FIGS. 1A and 1B, a power supply system 10 according to an embodiment of the first invention is a gas engine that supplies power to a plurality of facilities 12, 12a, and 12b together with a commercial system 11. A generator (GE) 13, 13 a, 13 b and a system stabilizing device (SSC) 14 that selectively cuts off the equipment 12, 12 a, 12 b due to a power failure of the commercial system 11, and a plurality of equipment 12, 12 a, 12 b To supply power. Hereinafter, these will be described in detail.

As shown in FIG. 1A, the power supply system 10 connected to the commercial system 11 includes a circuit breaker 15 connected to the commercial system 11 and a power supply network 16 connected to the circuit breaker 15. . While the commercial system 11 is energized, power is transmitted from the commercial system 11 to the power supply network 16 via the circuit breaker 15 and when the commercial system 11 is out of power, the power supply network 16 is as shown in FIG. The circuit breaker 15 disconnects the commercial system 11.
Hereinafter, the disconnection of the power supply network 16 from the commercial system 11 is also referred to as system separation.

While the commercial system 11 is energized, as shown in FIG. 1A, the plurality of gas engine generators 13, 13a, 13b are electrically connected to the power supply network 16 via the circuit breakers 17, 17a, 17b, respectively. The plurality of facilities 12, 12 a, 12 b that operate by receiving power supply are electrically connected to the power supply network 16 through the circuit breakers 18, 18 a, 18 b, respectively. Therefore, the power from the plurality of gas engine generators 13, 13a, 13b and the power from the commercial system 11 can be supplied to the facilities 12, 12a, 12b.
As shown in FIGS. 1A and 1B, the power supply network 16 is connected to a gas engine generator other than the gas engine generators 13, 13a and 13b and facilities other than the facilities 12, 12a and 12b. May be. Hereinafter, in order to simplify the description, it is assumed that only the gas engine generators 13, 13 a, 13 b and the facilities 12, 12 a, 12 b are connected to the power supply network 16.

The circuit breaker 17 switches between a connected state in which the gas engine generator 13 can transmit power to the power supply network 16 and a disconnected state in which the gas engine generator 13 cannot transmit power to the power supply network 16 as necessary. The circuit breaker 17 can detect the amount of power (W) per unit time output from the gas engine generator 13 electrically connected to the power supply network 16.
The relationship of the circuit breaker 17a to the gas engine generator 13a and the relationship of the circuit breaker 17b to the gas engine generator 13b are the same as the relationship of the circuit breaker 17 to the gas engine generator 13b.

Control units 19, 19a, 19b for adjusting the outputs of the gas engine generators 13, 13a, 13b are connected to the gas engine generators 13, 13a, 13b, respectively.
The control unit 19 is mainly composed of a computer loaded with various programs, detects the frequency of the power output from the gas engine generator 13, and adjusts the output of the gas engine generator 13 based on the detected value. Specifically, when the frequency of the gas engine generator 13 is higher than the rated frequency of the gas engine generator 13, the output of the gas engine generator 13 is lowered, and the frequency of the gas engine generator 13 is set to the rated value of the gas engine generator 13. When the frequency is lower than the frequency, the output of the gas engine generator 13 is increased.

The relationship between the control unit 19 and the gas engine generator 13 is the same in the relationship between the control unit 19a and the gas engine generator 13a and the relationship between the control unit 19b and the gas engine generator 13b.
In the present embodiment, the gas engine generators 13, 13a, 13b each have a maximum increase / decrease of 15% / min and a rated frequency of 60 Hz.

Further, the gas engine generator 13 (the same applies to the gas engine generators 13a and 13b) has a protection circuit when the frequency of output power is 95% or less of the rated frequency or 115% or more of the rated frequency. Operates and stops. Therefore, in order to continue the power generation by the gas engine generator 13, it is necessary to maintain the frequency of the electric power output from the gas engine generator 13 in the range of more than 95% of the rated frequency and less than 115%.

The gas engine generators 13, 13a, and 13b have different maximum outputs (maximum amounts of power that can be output per unit time), and in the present embodiment, the maximum outputs are 6 MW, 5 MW, and 4 MW, respectively. Therefore, the maximum output of the gas engine generators 13, 13a, 13b is in a relationship of gas engine generator 13> gas engine generator 13a> gas engine generator 13b.

The circuit breaker 18 can switch between a connected state where the facility 12 can receive power supply via the power supply network 16 and a non-connected state where the facility 12 cannot receive power supply via the power supply network 16. Furthermore, the circuit breaker 18 can detect the power consumed by the equipment 12 per unit time (hereinafter also referred to as “load”). The relationship between the circuit breaker 18a and the facility 12a and the relationship between the circuit breaker 18b and the facility 12b are the same as the relationship between the circuit breaker 18 and the facility 12.
And when the system isolation | separation arises by the power failure of the commercial system 11, the system | strain stabilization apparatus 14 which selectively interrupts | blocks the installations 12, 12a, 12b according to setting is connected to the circuit breakers 18, 18a, 18b.

The system stabilizing device 14 is also connected to the circuit breaker 15 and circuit breakers 17, 17a, 17b, and can detect whether the system is separated from the state of the circuit breaker 15, and each of the circuit breakers 17, 17a, 17b can be detected. The detection value and the detection value of each of the circuit breakers 18, 18a, 18b can be acquired.
When the system is separated, in the power supply system 10, the power supply to the facilities 12, 12 a, 12 b is performed from the normal operation performed by the commercial system 11 and the gas engine generators 13, 13 a, 13 b, and the gas engine power generation. The shift to the single operation performed only by the machines 13, 13a, 13b is performed.

When the system stabilization device 14 detects from the state of the circuit breaker 15 that the system has been separated due to a power failure of the commercial system 11, the detected value of each of the circuit breakers 17, 17a, 17b and each of the circuit breakers 18, 18a, 18b Based on the detected value, the difference between the total output (total power) of the gas engine generators 13, 13a, 13b and the total load of the facilities 12, 12a, 12b is calculated.
When the system stabilizing device 14 detects that the total load is larger than the total output, the system stabilizing device 14 shuts off the predetermined facility.

For example, if the system stabilization device 14 is set to shut off the equipment 12b in preference to the equipment 12, 12a, the system stabilization device 14 sends a command signal to the circuit breaker 18b to turn off the circuit breaker 18b. The power supply to the equipment 12b is cut off in the connected state.
During normal operation, the supply and demand of electric power is achieved by adding the total output of the gas engine generators 13, 13a, and 13b to the output of the commercial system 11 for the power demand that is the total load of the facilities 12, 12a, and 12b. Balanced. If a power failure occurs in the commercial system 11 from this state, simply, the power supply for the output of the commercial system 11 is insufficient, and the power demand greatly exceeds the power supply.
Therefore, the power supply / demand imbalance in which the power demand greatly exceeds the power supply is eliminated by the selective shutoff of the facilities 12, 12a, 12b by the system stabilizing device 14.

In addition, as shown in FIG. 1A, power storage means 21 that adjusts the supply and demand balance of power by charging and discharging is connected to the power supply network 16 via a circuit breaker 22. And the control part 23 which controls charging / discharging of the electric power storage means 21 is connected to the electric power storage means 21 which has a storage battery.
The circuit breaker 22 can detect the charge amount (W) per unit time of the power storage means 21 and the discharge amount (W) per unit time of the power storage means 21, and the power storage means 21 can detect the power supply network 16. And the state in which the power storage means 21 is not electrically connected to the power supply network 16 can be switched.

The control unit 23 includes a computer loaded with a program, and can detect the frequency of power supplied from the commercial system 11 and the gas engine generators 13, 13a, 13b to the power storage means 21 when the commercial system 11 is energized. When the system 11 is out of power, the frequency of the power supplied from the gas engine generators 13, 13a, 13b to the power storage means 21 can be detected.
When the control unit 23 shifts from the normal operation to the single operation, the control unit 23 controls the charge / discharge of the control unit 23 according to the frequency of the detected power, and adjusts the power supply / demand balance. Specifically, the control unit 23 charges the power storage means 21 when the frequency of the power output from the gas engine generators 13, 13a, 13b is higher than the rated frequency of the gas engine generators 13, 13a, 13b. The power storage means 21 is discharged when the frequency is lower than the rated frequency of the gas engine generators 13, 13a, 13b.

Here, when the frequency of the electric power output from the gas engine generators 13, 13a, 13b is higher than the rated frequency of the gas engine generators 13, 13a, 13b, the total output of the gas engine generators 13, 13a, 13b is It means that the total load of the facilities 12, 12a, 12b is exceeded. On the other hand, when the frequency of the electric power output from the gas engine generators 13, 13a, 13b is smaller than the rated frequency of the gas engine generators 13, 13a, 13b, the total output of the gas engine generators 13, 13a, 13b is equipment. It means that it is smaller than the total load of 12, 12a and 12b.

Since the output adjustment of the gas engine generators 13, 13a, 13b is also performed when the supply and demand of electric power is unbalanced, each of the gas engine generators 13, 13a, 13b is changed during the transition from the normal operation to the single operation. Output adjustment and charging / discharging of the power storage means 21 are performed.
Needless to say, the output adjustment of the gas engine generators 13, 13a, 13b is performed not only during the transition from the normal operation to the single operation but also during the single operation.

In the present embodiment, the power storage means 21 has a maximum output of 5.5 MW, and in order to shift from charging to discharging, it is necessary to gradually reduce the charging amount and make the charging amount zero before discharging. This is the same when switching from discharging to charging.
Here, the maximum increase / decrease amount per unit time of charging or discharging of the power storage means 21 is larger than the maximum increase / decrease amount per unit time of the gas engine generator, for example, 70 to 100 times larger. That's it.
The maximum output of 5.5 MW means that both the upper limit of the discharge amount per unit time and the upper limit of the charge amount per unit time are 5.5 MW. In the present embodiment, charging and discharging of the power storage unit 21 are collectively referred to as an output of the power storage unit 21.

The maximum output 5.5 MW of the power storage means 21 is 0.5 times or more than the maximum output 6 MW of the gas engine generator 13 having the largest maximum output among the gas engine generators 13, 13 a, 13 b. The range is 0 times or less.
Here, if the power storage means has a maximum output of 0.5 to 1.0 times the maximum output of the gas engine generator with the largest maximum output, the maximum output needs to be 5.5 MW. Absent.

Hereinafter, a power storage means having a maximum output of 0.5 to 1.0 times the maximum output of the gas engine generator 13 having the largest maximum output among the gas engine generators 13, 13a and 13b. The reason for adopting 21 will be described.
In the power supply system 10, the power supply state largely changes due to a power failure of the commercial system 11, so that the facilities 12 and 12 a other than the facility 12 b blocked by the system stabilizing device 14 can be stopped.

When one or both of the facilities 12, 12a are stopped, the total output of the gas engine generators 13, 13a, 13b greatly exceeds the total load of the operating facilities (hereinafter also simply referred to as “total output”). It becomes a state. If this surplus amount is at a level that cannot be eliminated by a decrease in the output of the gas engine generators 13, 13a, 13b and charging of the power storage means 21, one of the gas engine generators 13, 13a, 13b, or 2 Is intentionally blocked. This is to prevent the gas engine generators 13, 13a, 13b from stopping unintentionally due to the operation of the protection circuit.

Here, if power storage means having a larger maximum output than the power storage means 21 is adopted instead of the power storage means 21, the total output of the gas engine generators 13, 13a, 13b greatly exceeds the total load. This can be eliminated by adjusting the output of the power storage means 21, and it is considered that the gas engine generators 13, 13a, 13b can be prevented from stopping due to the operation of the protection circuit.
However, if the power storage means with a large maximum output is adopted, the introduction cost of the power storage means naturally increases. Therefore, it is not preferable in terms of cost to employ the power storage means with a larger maximum output than necessary. Therefore, in the present embodiment, 1.0 times the maximum output of the gas engine generator 13 having the largest maximum output is set as the upper limit of the maximum output of the power storage unit 21.

Moreover, in this Embodiment, control part 19,19a, 19b is required based on the raise speed | velocity | rate or frequency value of the frequency of the electric power output from the gas engine generator 13,13a, 13b corresponding to each. In response, the corresponding gas engine generator is intentionally shut off.
The output adjustment of the power storage means 21 and the gas engine generators 13, 13a, 13b is performed by selectively shutting off one or two of the corresponding gas engine generators 13, 13a, 13b by the control units 19, 19a, 19b. Just adjusting the gap between power supply and demand at a level that cannot prevent the gas engine generator from shutting down due to the operation of the protection circuit.
In the present embodiment, the control means for adjusting the unbalance of the power supply and demand caused by the power failure of the commercial system 11 by the selective cutoff of the gas engine generators 13, 13 a and 13 b and the charge and discharge of the power storage means 21 is the control unit. 19, 19 a, 19 b and the control unit 23.

Here, if the power storage means whose maximum output is less than 0.5 times the maximum output of the gas engine generator 13 is adopted, even if the gas engine generators 13, 13a, 13b are selectively cut off, the normal operation is performed independently. Various verifications have revealed that the transition to operation cannot be performed stably.
After the selective shutoff of the gas engine generators 13, 13 a, 13 b, the largest power supply / demand gap is 0.5 times the maximum output of the gas engine generator 13. 1) When the value obtained by subtracting demand from the supply of electric power is more than 0.5 times the maximum output of the gas engine generator 13 and 1.5 times or less, the intention of the gas engine generator 13 Due to the interruption, the power supply / demand gap is kept below 0.5 times the maximum output of the gas engine generator 13, and 2) the value obtained by subtracting the demand from the power supply is the maximum of the gas engine generator 13. If the output is 0.5 times or less, the power supply / demand gap is 0.5 times or less the maximum output of the gas engine generator 13 by not selectively cutting off the gas engine generators 13, 13a, 13b. It can be seen from that can be maintained.

Therefore, if the power storage means whose maximum output is less than 0.5 times the maximum output of the gas engine generator 13 is adopted, even if the power storage means is charged and discharged at the maximum output, the power supply-demand gap However, the state where the maximum output of the gas engine generator 13 is 0.5 times cannot be resolved.
Considering that the maximum increase / decrease amount of the output of the gas engine generator is significantly smaller than the maximum increase / decrease amount of charge / discharge of the power storage means, the total output immediately after the system stabilizer 14 is activated exceeds the total load. In order to stably complete the transition from the normal operation to the single operation, it is important to eliminate the current state only by selectively shutting off the gas engine generator and charging / discharging the power storage means.

And also by simulation, it was confirmed that a power storage means having a maximum output of 0.5 times or more with respect to the maximum output of the gas engine generator having the maximum maximum output was necessary. The simulation results are shown in FIG.
The upper graph in FIG. 2 shows the transition of the frequency of the power output from the gas engine generator after the system separation. And the electric power storage means (henceforth "the electric power storage means for 0.5 units of GE") which has the maximum output of 0.5 time with respect to the maximum output of the gas engine generator with the largest maximum output was used. And a case where power storage means having a maximum output of 0.1 times (hereinafter also referred to as “power storage means for 0.1 GE”) are described. The vertical axis indicates the rated frequency as 100%, the frequency of the gas engine generator in%, and the horizontal axis indicates the passage of time.
It is assumed that the gas engine generator is stopped by the operation of the protection circuit when it is out of the range higher than 95% of the rated frequency and lower than 115%.

The lower graph of FIG. 2 shows the transition of the total output of the plurality of gas engine generators after the system separation and the transition of the output of the power storage means, and the line on the graph indicated by GE indicates the plurality of gas engines. The total output of the generator is shown. As for the output of the power storage means, charging is not performed at the time of system separation, the lower side from the system separation means charging, and the upper side from the system separation means discharging.

In this simulation, it is assumed that an accident occurred in the commercial system at the time of 3 seconds indicated by (a) on the horizontal axis. As a result, system separation and system stability by disconnecting the accident point by 3.5 seconds The equipment is selectively shut off by the operation of the gas generator, and the power supply of the gas engine generator and the power demand of the equipment are generally balanced, but in general, the power supply may be excessive with respect to the power supply and demand. In many simulations, the frequency tends to increase. Thereafter, the gas engine generator is selectively cut off at the point of 5 seconds marked (b) (in the example of FIG. 2, one gas engine generator is selectively cut off).
From the upper graph of FIG. 2, when the power storage means for 0.5 GE is used, the frequency of the power output from the gas engine generator that has risen immediately after the system separation is determined is the operation of the system stabilizing device. It rises later, and the rate of frequency increase decreases with the selective shutoff of the gas engine generator. Then, the frequency of the power output from the gas engine generator starts to decrease around 9 seconds when the charging (output) of the power storage means becomes maximum, and then gradually decreases after reaching the rated frequency around 28 seconds. It can be seen that it increases and decreases and converges.

And when the power storage means for 0.5 units of GE is used, since the frequency is within the range higher than 95% and lower than 115%, it is confirmed that the gas engine generator does not stop due to the operation of the protection circuit. did it.
On the other hand, when the power storage means for 0.1 units of GE is used, the frequency of the power output from the gas engine generator is still rising even if it exceeds 115%, and has reached 115%. At that time, it was confirmed that the gas engine generator stopped due to the operation of the protection circuit.

From the lower graph of FIG. 2, it can be seen that the total output of the gas engine generator drops rapidly due to the selective cut-off of the gas engine generator and then gradually decreases around 28 seconds. This is because the gas engine generator reduces the output by adjusting the output in order to reduce the frequency of the electric power output from the gas engine generator exceeding the rated frequency.
In addition, the power storage means starts charging and reduces the frequency of power output from the gas engine generator after the system separation to a state of maximum charging 10 seconds before (maximum output state). It has become.

The output of the gas engine generator and the output of the power storage means decrease when the frequency of the electric power output from the gas engine generator exceeds the fixed frequency, and when the frequency falls below the rated frequency. To increase.
When the supply and demand balance of electric power is achieved only by adjusting the output of the gas engine generator, the output adjustment of the power storage means is completed, and the transition to the single operation is completed.

In this simulation, when the power storage means for 0.1 units of GE is used, until the frequency of the power output from the gas engine generator reaches 115%, the output adjustment of the gas engine generator and the power storage means The output adjustment is equal when the power storage means for 0.1 GE is used and when the power storage means for 0.5 GE is used, and is as shown in the lower graph of FIG.
When the power storage means for 0.1 GE is used and the frequency of the power output from the gas engine generator reaches 115%, the gas engine is used for the power storage means for GE 0.1. The total output of the generator is 0, but this is omitted from the graph in the lower part of Fig. 2, and only the transition of the output when power storage means for 0.5 units of GE is used is shown. .

Next, a power supply and demand adjustment method according to an embodiment of the second invention will be described.
First, the power supply system 10 is constructed by providing a plurality of gas engine generators 13, 13 a, 13 b, a system stabilizing device 14, a power storage unit 21, and control units 19, 19 a, 19 b, 23, and the like.
Then, according to the flow shown in FIG. 3 and FIG. 4, the unbalance of the power supply and demand caused by the power failure of the commercial system 11 is selected and the plurality of gas engine generators 13, 13 a and 13 b are selectively cut off and the power storage means 21 is charged. Adjust by discharge.

Specifically, as shown in FIG. 3, when the commercial system 11 is out of power during normal operation (S1) (S2), the system stabilizing device 14 is connected to the gas engine generators 13, 13a, 13b. It is determined whether or not the total output is greater than the total load of the equipment 12, 12a, 12b (S3), and if the total output is not greater than the total load, it is determined whether or not the total output is less than the total load. (S4).

Usually, immediately after the power failure of the commercial system 11, the total output is less than the total load, and in that case, the system stabilizing device 14 performs selective blocking of the plurality of facilities 12, 12a, 12b according to the set priority (S5). ). Then, returning to S3, the system stabilizing device 14 determines again whether or not the total output is larger than the total load. S3 to S5 are performed until the total output exceeds the total load, and when the total output becomes larger than the total load, the control unit 19 calculates the total from the total output based on the frequency of the power output from the gas engine generator 13. It is determined whether the value obtained by subtracting the load exceeds 0.5 times the maximum output of the gas engine generator 13 (S6).

In S6, when it is determined that the value obtained by subtracting the total load from the total output exceeds 0.5 times the maximum output of the gas engine generator 13, the gas engine generator 13 is shut off by the control unit 19. The outputs of the remaining gas engine generators 13a and 13b and the output of the power storage means 21 are reduced (S7). In addition, the reduction of the output of the electric power storage means 21 means decreasing the amount of discharge when discharging, and increasing the amount of charging when charging.

Next, the control unit 19a determines whether or not the value obtained by subtracting the total load from the total output is equal to or less than 0.5 times the maximum output of the gas engine generator 13a (S8). If it is not less than 0.5 times the maximum output of the generator 13a, the process returns to S7 to stop the gas engine generator 13a and reduce the output of the gas engine generator 13b and the output of the power storage means 21. (S7).

S7 and S8 are repeated until one gas engine generator is generating power. In S8, the value obtained by subtracting the total load from the total output is less than 0.5 times the maximum output of the gas engine generator. Whether or not the total output is greater than the total load is determined by the control unit connected to the operating gas engine generator and the control unit 23 (S9). This determination is made based on the frequency of the electric power being output from the operating gas engine generator.

When the total output is larger than the total load, as shown in FIG. 4, the output and power storage of the operating gas engine generator until the frequency of the power output from the gas engine generator reaches the rated frequency. The output of the means 21 is reduced (S10, S11).
On the other hand, if the total output is not larger than the total load in S9, it is determined whether the total output is smaller than the total load as shown in FIG. 3 (S12). As shown in FIG. 4, the output of the operating gas engine generator and the output of the power storage means 21 are increased until the frequency of the output power reaches the rated frequency (S13, S14). The increase in the output of the power storage means 21 means that the power storage means 21 decreases the charge amount when charging, and the discharge amount increases when the power storage means 21 is discharging.

If it is determined in S11 or S14 that the frequency of the power output from the gas engine generator has reached the rated frequency, the output of the power storage means 21 is 0 (the state where the power storage means 21 is not charged / discharged). Thus, the output fluctuation of the power storage unit 21 is converged (S15, S16). At the time of this convergence, the output of the power storage means 21 is increased or decreased within an allowable range for increasing or decreasing the output of the gas engine generator.
Here, in S4 and S12, as shown in FIG. 3, even when it is determined that the total output is not smaller than the total load, that is, the total output is equal to the total load, the output of the power storage means 21 is also determined by S15 and S16. Variation convergence is performed.
Then, as shown in FIG. 4, when the output of the power storage means 21 becomes 0 and the power supply / demand balance is achieved only by adjusting the output of the operating gas engine generator, the transition to the single operation is completed ( S17).

Further, in the storage battery, the charge / discharge time (h), the capacity (Wh), and the maximum output (W) are in a relationship of charge / discharge time (h) = capacity (Wh) / maximum output (W).
As a result of various studies, it has been confirmed that it is 3 to 5 minutes from the power failure of the commercial system to the completion of the transition to the single operation, and the charge / discharge time of the storage battery generally used in the power supply system is 0.5. ~ 7 (h). Therefore, if it is a general storage battery assumed to be used, the charge / discharge time satisfies the condition as the storage battery of the power storage means 21.

And the electric power storage means 21 is calculated | required to have the maximum output of at least 0.5 time with respect to the maximum output of the gas engine generator 13, Furthermore, the price of a storage battery is generally influenced by a capacity | capacitance. .
Considering these, by adopting a storage battery with a large maximum output relative to the unit capacity, the storage battery capacity can be reduced and the introduction cost of the storage battery can be suppressed to ensure the required maximum output. be able to.

As the storage battery that the power storage means 21 has, at least a lead storage battery, a sodium sulfur battery, a nickel metal hydride battery, or a lithium ion battery can be adopted, but a lithium ion battery having a large maximum output per unit capacity should be adopted. Therefore, the capacity of the storage battery can be reduced, and the introduction cost of the storage battery can be suppressed.
The lead storage battery, sodium sulfur battery, nickel metal hydride battery, and lithium ion battery have charge / discharge time rates of lead storage battery = 1 (h), sodium sulfur battery = 6 to 7 (h), nickel metal hydride battery = 1 ( h), lithium ion battery = 0.5 (h).

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and all changes in conditions and the like that do not depart from the gist are within the scope of the present invention.
For example, it is not necessary for the gas engine generator having the largest maximum output among the plurality of gas engine generators to be shut off first by the control means during the transition to the single operation.

10: Power supply system, 11: Commercial system, 12, 12a, 12b: Equipment, 13, 13a, 13b: Gas engine generator, 14: System stabilization device, 15: Circuit breaker, 16: Power supply network, 17, 17a, 17b: circuit breaker, 18, 18a, 18b: circuit breaker, 19, 19a, 19b: control unit, 21: power storage means, 22: circuit breaker, 23: control unit

Claims (4)

A power supply system comprising a gas engine generator that supplies power to a plurality of facilities together with a commercial system, and a system stabilization device that selectively cuts off the facility due to a power failure of the commercial system,
There are a plurality of gas engine generators,
An electric power storage means having a maximum output not less than 0.5 times and not more than 1.0 times the maximum output of the gas engine generator having the largest maximum output, and an imbalance between power supply and demand caused by a power failure of the commercial system, A power supply system comprising: control means for adjusting by selectively shutting off the gas engine generator and charging / discharging of the power storage means. The power supply system according to claim 1, wherein the power storage means includes a lithium ion battery. A plurality of gas engine generators for supplying power to a plurality of facilities together with a commercial system, a system stabilizing device for selectively cutting off the facilities due to a power failure of the commercial system, and a maximum of the gas engine generator having the largest maximum output A power storage means having a maximum output of 0.5 to 1.0 times the output;
An electric power supply and demand adjustment method, wherein an unbalance of electric power supply and demand caused by a power failure of the commercial system is adjusted by selectively shutting off the gas engine generator and charging and discharging the electric power storage means. 4. The power supply / demand adjustment method according to claim 3, wherein the power storage means includes a lithium ion battery.

Images