JP2007006595A - Operation method of private power generator set with power storage means - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an operation method of a private power generator set that removes a malfunction caused by a load variation, in operating a private power generator set independently of a commercial system. <P>SOLUTION: In the operation method of the private power generator set that comprises a generator connected to the commercial system at a normal time and driven by a prime mover independently of the commercial system at the power interruption or the like of the commercial system, a power storing means, and the private power generator set equipped with a charge and discharge control device that controls the charge and the discharge of the power storing means: when an increase in load is detected (S21), the power storage means is made to burden the increase of the load by making the power storage means discharge electricity (S22); after that, an output of the power storage means is gradually reduced at a speed not higher than that of an allowable variation of the load of the generator (S23); when the output of the power storage means becomes zero (S24), the load sharing by the power storage means is finished; an output frequency F of the generator is monitored; when the lowering of the output frequency is detected (S25), an output of the private power generator set is increased (S26); and when the output frequency reaches a rated frequency (S27), the load sharing is finished. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a load fluctuation during a self-sustained operation in a private power generation facility (for example, a cogeneration system) having a generator that is connected to the commercial system during normal operation and is driven by a prime mover independently from the commercial system at the time of a power failure of the commercial system. It is related with the driving method corresponding to.

  An example of the configuration of the private power generation facility connected to the commercial system will be described with reference to FIG. The private power generation facility 1 includes a prime mover 11, a generator 12 driven by the prime mover 11, a frequency control device 13 that monitors the frequency of the output of the generator 12 and controls the frequency of the prime mover 11, and the generator 12, and a voltage control device 14 that controls the output voltage of the generator by monitoring the output voltage of 12, and is connected to the local distribution line 2. The on-site distribution line 2 is separably connected to the commercial system 3 by a system separation breaker 21. A plurality of loads 22-1 to 22-5 are connected to the local distribution line 2 via load circuit breaker switches 23-1 to 23-5.

  Here, it is assumed that the load 22-1 to the load 22-3 must supply power without interruption, the load 22-4 is an important load, and the load 22-5 is a general load.

  When such an in-house power generation facility 1 is operated not in the grid connection with the commercial system 3 but in a so-called independent system, the voltage and frequency of the generator 12 vary due to the variation of the load 22. The private power generation facility 1 is provided with a frequency control device 13 composed of a governor and the like, and a voltage control device 14 composed of an AVR (automatic voltage regulator) or the like. It is controlled to fit in. In the control by the frequency control device 13 and the voltage control device 14 of this generator, as shown in FIG. 6, it takes several seconds to several tens of seconds.

  In such a system, depending on the characteristics of the generator 12 and the load (electric motor) 22, if there is a large load fluctuation, the fluctuation in voltage or frequency is large, and the generator 12 trips or the load device 22 stops. There is a bug. Generally, the allowable load fluctuation amount is 10% to 30% of the rated capacity. In other words, a load exceeding the allowable load fluctuation amount cannot be set as a load at the time of self-sustained operation unless measures such as a star delta start-up are used to suppress a start-up current. On the other hand, in order to make the load a load at the time of independent operation, it was necessary to increase the capacity of the private power generation facility.

  For this reason, when there are a lot of loads, it is necessary to take measures such as sequential activation, resulting in high costs. Moreover, the operation rate of the private power generation equipment at the time of a self-sustained operation was about 30 to 70%. For this reason, partial load operation has occurred, and the power generation efficiency during the independent operation has been reduced.

In order to cope with such a problem, a power generation facility using a generator driven by a prime mover such as an internal combustion engine, a power conversion device that converts power generated by the power generation facility, and the power generation facility A control device for detecting an output of the power generation facility, a capacity of the power storage facility and a load power in a private power generation facility including a power storage facility for storing electric power, and controlling the output to the power generation facility in accordance with a load variation Has been proposed (see, for example, Patent Document 1).
JP 2001-112176 A

  The present invention provides an operation method that eliminates inconveniences caused by load fluctuations when operating the private power generation facility independently from the commercial system, such as when a power failure occurs in the commercial power system. With the goal.

  The present invention relates to a generator that is connected to a commercial system during normal operation and is driven by a prime mover independently from the commercial system at the time of a power failure of the commercial system, power storage means, and charge / discharge that controls charging / discharging of the power storage means In the method for operating a private power generation facility equipped with a control device, when an increase in load is detected, the output is discharged (discharged) from the power storage means to cause the power storage means to bear the increased load, and then the output of the power storage means Is gradually reduced at a speed equal to or lower than the allowable fluctuation load of the generator, and when the output of the power storage means becomes 0, the load sharing process is terminated. Furthermore, the present invention monitors the output frequency of the generator in the method for operating the private power generation facility, and if the output frequency is detected to decrease, the output of the private power generation facility is increased and the output frequency reaches the rated frequency. Then, the load sharing process ends.

  The present invention relates to a generator that is connected to a commercial system during normal operation and is driven by a prime mover independently from the commercial system at the time of a power failure of the commercial system, power storage means, and charge / discharge that controls charging / discharging of the power storage means In a method of operating a private power generation facility equipped with a control device, when a decrease in load is detected, power is input (charged) to the power storage means, and then the power storage means is gradually input at a speed equal to or less than the allowable fluctuation load of the generator. When the input of the power storage means becomes 0, the load sharing process is terminated. Furthermore, the present invention monitors the output frequency of the generator in the operation method of the private power generation facility, and if the output frequency is detected to increase, the output of the private power generation facility is decreased and the output frequency reaches the rated frequency. Then, the load sharing process ends.

  According to the present invention, it is possible to increase the capacity and the number of loads that can be connected to the private power generation equipment, and for the same load, the capacity of the private power generation equipment 1 that is required can be reduced, and the equipment cost is reduced. Can be reduced.

  Further, according to the present invention, since it is not necessary to sequentially load the equipment, the equipment cost can be reduced and the equipment design can be simplified. Moreover, the operation rate of the load at the time of a self-supporting operation can be improved.

  Hereinafter, an operation method when the private power generation facility according to the present invention is not connected to a commercial system will be described with reference to the drawings. The configuration of the power generation portion of the private power generation facility linked to a commercial system in which the power storage means is combined with the rotary private power generation facility to which the present invention is applied will be described with reference to FIG.

  The private power generation facility 1 to which the operation method according to the present invention is applied includes a prime mover 11, a generator 12 driven by the prime mover 11, and the frequency of the output of the generator 12 to monitor the frequency of the prime mover 11. A frequency control device 13 that monitors the output voltage of the generator 12 to control the output voltage of the generator, a power storage means 15 that can store or release power, and the power storage means 15 And a charge / discharge control device 16 that controls charging / discharging of the premises, and is connected to the local distribution line 2. The on-site distribution line 2 is separably connected to the commercial system 3 by a system separation breaker 21. A plurality of loads 22-1 to 22-5 are connected to the local distribution line 2 via load circuit breaker switches 23-1 to 23-5.

  As the prime mover 11, a gas engine, a gas turbine engine, a diesel engine, or the like can be used, and can be applied to a cogeneration system.

  The power storage means 15 may be any equipment as long as it has the ability to store electric power. For example, a lead storage battery, a nickel hydride storage battery, a lithium ion storage battery capacitor, a flywheel, and the like can be used. .

  The charge / discharge control device 16 that controls charging / discharging of the power storage unit 15 uses a power conversion device that converts the DC voltage of the power storage unit 15 into AC power and converts the AC output power of the generator 12 into DC power. And means for monitoring the state of the load, and means for changing the power conversion direction according to the state of the load. This control can be controlled by the load power P of the power generation facility 1 or the output frequency of the generator 12.

  The present invention combines a power storage means such as a storage battery with a private power generation facility, stores the power in the power storage means during grid connection, and the load fluctuates to require a power that exceeds the allowable power of the generator The power storage means bears the load fluctuation at the time of fluctuation, and then gradually reduces the share of the power storage means at the speed of the load fluctuation range allowed by the private power generation equipment, and transfers the share of the power storage means to the generator Let

  That is, when the load increases, the incremental power is supplied by discharging the power storage means, and then the discharge amount is gradually reduced. As a result, the amount of power generation is reduced with respect to the load amount, and thus the frequency is reduced. The private power generation facility increases the frequency by gradually increasing the output by the frequency control already provided. By finally setting the discharge of the power storage means to 0, the load increment can be transferred to the private power generation facility. If the rate of increase in the generator output of the private power generation facility is set to be equal to or less than the maximum speed that the private power generation facility can follow, it is possible to cope with a rapid and large load fluctuation without tripping the generator.

  On the other hand, in the case of load reduction, the output of the surplus generator is charged in the power storage means, and then the charge in the power storage means is gradually reduced. As a result, the amount of power generation increases with respect to the amount of load, so that the frequency increases. Finally, by reducing the charging of the power storage means to 0, the load decrement can be transferred to the private power generation facility.

  As a result, even if a load fluctuation exceeding the load fluctuation allowed by the private power generation facility occurs, the private power generation facility can be operated smoothly without suppressing the load variation. In addition, it is possible to suppress fluctuations in the output frequency and output voltage of the generator by mitigating fluctuations in the private power generation equipment by the power storage means even for load fluctuations within the allowable load fluctuation of the private power generation equipment. .

  The method for operating a private power generation facility according to the present invention is applied during system separation when the circuit breaker 21 is open. That is, when the private power generation facility is stopped, the commercial system is blacked out when the loads 22-1 to 22-5 are turned on after the circuit breaker 21 is opened and the private power generation facility is activated, or during the private power generation facility interconnection operation. When the circuit breaker 21 is opened, the load input rate of the private power generation facility can be improved by charging / discharging the power storage means when the loads 22-1 to 22-5 fluctuate.

  The private power generation facility 1 performs constant frequency control by the frequency control device (governor) and constant low voltage control by the voltage control device (AVR) during the independent operation. When the load is turned on, the output frequency and voltage of the generator decrease. The frequency is detected and the output increase and the voltage increase are controlled to make the frequency and voltage constant. In the conventional operation method, when a load exceeding the allowable input amount is applied, the frequency and voltage are lowered too much, the protection device works and the private power generation facility trips, and the load facility is affected by the decrease in frequency and voltage. However, in the present invention, the load input is detected, and the same capacity is first discharged from the power storage means, and then the power storage means decreases the output at a speed equal to or less than the allowable fluctuation amount.

  In general, the allowable load fluctuation rate of the private power generation facility has a larger load decrease than a load increase. Some power storage means have a slower charging speed than a discharging speed. Therefore, the load sharing method at the time of load fluctuation can be considered to be burdened by the power storage means only at the time of load increase, or to be burdened by both load increase and load decrease.

  Of the load sharing methods when the load fluctuates, a case where the power storage means bears only when the load increases will be described with reference to FIG. The charge / discharge control device 16 monitors the presence / absence of a load change (S1), and when there is a load change ΔP, determines whether or not the load is increased (S2). When the load fluctuation is an increase in the load, the power storage unit 15 is controlled to be in the ΔP output (discharge) state (S3). Thereafter, the output (discharge) of the power storage means is gradually reduced at the speed (Va (kw / s)) below the allowable variable load in the power generation equipment (S4). It is determined whether the output of the power storage means 15 has become 0 (S5), and when it has become 0, the load variation sharing process is terminated.

  In step S2, when the load decreases, the frequency F increases (S6), so the private power generation facility decreases the output according to its own frequency control (S7), and monitors whether the frequency F has returned to the rated frequency. Then, when returning to the rated frequency (S8), the load variation sharing process is terminated.

  In step S4, in the process of decreasing the output of the power storage means, when the frequency F decreases below the rated frequency (S9), the private power generation facility increases the output (S10), and the frequency F returns to the rated frequency. Whether or not it has been monitored (S11), and when it returns to the rated frequency, the load variation sharing process is terminated.

  A case where the power storage means shares the load both in the load increase and the load decrease will be described with reference to FIG. The charging / discharging control blue 16 determines whether or not a load increase has occurred (S21), and controls the power storage means 15 to output (discharge) when the load increase occurs (S22). Thereafter, the output (discharge) of the power storage means 15 is gradually reduced at a speed equal to or lower than the allowable variable load of the power generation equipment (S23). It is determined whether the output of the power storage unit 15 is 0 (S24). When the output is 0, the load sharing process is terminated. In step S23, the output frequency F of the generator 12 is monitored. When the frequency F drops below the rated frequency, the private power generation equipment automatically increases the output (S26), and when the frequency F reaches the rated number. Then, the load sharing process is terminated.

  If it is determined in step S21 that the load has not increased, it is monitored whether or not a negative addition / subtraction has occurred (S28). When negative addition / subtraction occurs, the power storage unit 15 is controlled to store the increased amount of power (S29), and thereafter, the input (storage) of the power storage unit 15 is gradually performed at a speed equal to or lower than the allowable fluctuation load of the power generation facility. When the input becomes 0 (S31), the load sharing process is terminated.

  In step S30, when the output frequency of the generator 12 is monitored and the frequency F increases (S32), the private power generation facility automatically decreases the output (S33), and when the output frequency F reaches the rated frequency (S34), End the load sharing process.

  The operation by the above processing will be described with reference to FIG. That is, when the load increases, the output of the generator 12 is affected by the load increase for a moment until the output from the power storage unit 15 is present, but returns to the output before the load increase by the output of the power storage unit 15. On the other hand, the output of the power storage means 15 once decreases the output at a constant speed after outputting the increased load. When the output frequency F of the generator 12 becomes equal to or less than the dead band Fu of the frequency control, the generator 12 increases the output at a speed equal to or lower than the allowable variable load according to its own frequency control.

  As described above, the present invention is effective in the case of a self-sustaining operation such as a power failure in a commercial system. Accordingly, during normal times, grid connection is performed, and the power storage means can be economically operated such as load leveling operation.

  Normally, the allowable load fluctuation amount of the private power generation facility 1 is 20 to 30% of the low-rated output in the no-load state, and about 5% in the 80% load state, depending on the characteristics of the prime mover 11. On the other hand, according to the present invention, since the power storage means once bears the load fluctuation, the allowable load fluctuation amount of the private power generation facility 1 is improved to nearly 100%.

  As a result, the capacity and number of loads that can be connected to the private power generation facility 1 can be increased. Therefore, for the same load, the capacity of the private power generation facility 1 can be reduced, and the facility cost can be reduced.

  Furthermore, according to the present invention, since it is not necessary to sequentially load the load, it is possible to improve the operating rate of the load during the independent operation.

The figure explaining the outline | summary of a structure of the private power generation equipment with which the operating method concerning this invention is applied. The flowchart (the 1) explaining the operation method of the private power generation equipment concerning this invention. The flowchart (the 2) explaining the operating method of the private power generation equipment concerning this invention. The figure explaining the state of the private power generation equipment by the operation method of the private power generation equipment concerning the present invention. The figure explaining the outline | summary of a structure of the conventional private power generation equipment. The figure explaining the state of the private power generation equipment by the operation method of the conventional private power generation equipment.

Explanation of symbols

  1: private power generation equipment, 11: prime mover, 12: generator, 13: frequency control device, 14: voltage control device, 15: power storage means, 16: charge / discharge control means, 2: on-site distribution line, 21: system interruption Machine, 22: load, 23: load circuit breaker, 3: commercial system.

Claims (4)

A generator that is connected to the commercial system at normal time and is driven by a motor independently from the commercial system at the time of a power failure of the commercial system, etc., a power storage means, and a charge / discharge control device that controls charging / discharging of the power storage means In the operation method of private power generation equipment that
When an increase in the load is detected, the output is discharged (discharged) from the power storage means so that the increase in the load is borne by the power storage means, and then the output of the power storage means is gradually increased at a speed equal to or lower than the allowable fluctuation load of the generator. A method for operating a private power generation facility, characterized in that the load sharing rate of the private power generation facility is improved by reducing the load and terminating the load sharing process when the output of the power storage means becomes zero.   The operation method of the private power generation facility according to claim 1, wherein when the output frequency of the generator is monitored and it is detected that the output frequency has decreased, the output of the private power generation facility is increased, and when the output frequency reaches the rated frequency, the load is increased. A method for operating a private power generation facility, characterized in that the sharing process is terminated. A self-contained power generator that is connected to a commercial system during normal operation and that is driven by a motor independently from the commercial system during a power outage of the commercial system, a power storage unit, and a charge / discharge control device that controls charging / discharging of the power storage unit In the operation method of the power generation equipment,
When a load decrease is detected, power is input (charged) to the power storage means, and then the input of the power storage means is gradually decreased at a speed equal to or lower than the allowable fluctuation load of the generator, and the input of the power storage means becomes zero. A method for operating a private power generator, wherein the load sharing process is terminated. 4. The method of operating a private power generation facility according to claim 3, wherein when the output frequency of the generator is monitored and an increase in the output frequency is detected, the output of the private power generation facility is decreased, and when the output frequency reaches the rated frequency, the load is reduced. A method for operating a private power generation facility, characterized in that the sharing process is terminated.

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