JP2012220330A - Distributed power generating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a distributed power generating system capable of correcting deviation of zero point (offset value) in measured power by providing a signal inverting means that inverts the positive and negative of a current signal from a current sensor to thereby reset the sum of calculated power value to zero.SOLUTION: A signal integration means 110 integrates a normal current signal and a current signal inverted by signal reverting means 109 for the same period of time. When the integrated value is substantially zero, a control means 112 calculates a first power based on the normal current signal and a voltage signal and a second power based on the inverted current signal and the voltage signal for the same period of time, and sets the sum of the first power and the second power to zero to thereby correct the zero point of the power value in an arithmetic circuit 111.

Description

  The present invention relates to a distributed power generation system that supplies AC power to a power system and a load in a customer in connection with the power system.

  Conventionally, for example, a configuration shown in FIG. 4 is disclosed for this type of distributed power generation system (see, for example, Patent Document 1).

  Hereinafter, the distributed power generation system disclosed in Patent Document 1 will be described.

  FIG. 4 is a block diagram of a conventional distributed power generation system.

  As shown in FIG. 4, the commercial power supply system 1 is connected to the load 9 via the power receiving point 2, the power measuring device 3, and the distribution board 11, and the received power P <b> 1 is supplied from the commercial power supply system 1 to the power receiving point 2. Electric power is supplied to the load 9 via the earth leakage breaker 13 in the distribution board 11 and the branch breaker 14b.

  The power generation device 4 includes a power generation unit 5 provided with a fuel cell, an inverter 6, a control device 7, and an auxiliary device 10. The inverter 6 adjusts the power generated by the power generation unit 5, and outputs the output power P2 as a distribution board. 11 is output to the load 9 via the branch breakers 14a and 14b in the circuit 11. The control device 7 receives the measurement signal S1 from the power meter 3, and based on this, controls the output operation of the inverter 6 by the control signal S4, the driving of the load 9 by the control signal S3, the driving of the auxiliary machine 10, and the like. The auxiliary machine 10 is driven by the output power P3 from the inverter 6, and is controlled by the control signal S2 of the control device 7.

  Further, in order to grasp the power consumed by the load 9, the power measuring instrument 3 is arranged at or near the power receiving point 2 to measure the received power P1 and the generated power P2, respectively.

  Here, when the power generation device 4 is in operation, if the power at the power receiving point 2 does not change during a certain period based on the measurement signal S1 sent from the power meter 3, the power meter 3 is disconnected or the like. Therefore, it is determined that a failure has occurred, and a stop signal is sent to the power generation unit 5 and the auxiliary machine 10 to stop the operation of the power generation device 4. Further, when the output of the inverter 6 is changed, the inverter 6 is gate-blocked for a short time, the output of the auxiliary machine 10 is changed, or the load 9 is changed, the measurement signal sent from the power meter 3 Even when the electric power at the power receiving point 2 based on S1 does not change during a certain period before and after being changed as described above, the same determination is made to stop the operation of the power generation device 4.

JP 2009-79935 A

  However, the conventional configuration has a problem that an abnormality of the power measuring instrument (current sensor) itself can be detected, but a deviation of the zero point (offset value) of the measured power in the power calculation circuit cannot be detected. It was.

  The present invention solves the above-described conventional problems, and by providing a signal inverting means for inverting the sign of the current signal from the current sensor, a normal current signal and an inverted current signal obtained by operating the signal inverting means. By correcting the deviation of the zero point of the power calculated in the power calculation circuit by setting the sum of the power values after calculation to zero, the zero point of the measured power can be automatically corrected, so accurate power measurement can always be performed. An object is to provide a distributed power generation system.

  A distributed power generation system that is connected to an electric power system via a plurality of electric wires, and that generates a DC power, and converts the DC power generated by the power generation apparatus into AC power and supplies it to a consumer load DC / AC power conversion means, current sensor for detecting the current of the electric wire on the system side from the load in the consumer, voltage detection means for detecting the voltage of the electric wire, current signal from the current sensor and the voltage detection means A power calculation circuit for calculating the measured power based on the voltage signal from, a signal inversion means for inverting the sign of the current signal from the current sensor, a signal integration means for integrating the current signal from the current sensor, A control means for controlling at least the power generation device, the DC / AC power conversion means, and the signal inversion means, and the control means is usually used when the signal inversion means is not operated. When the value obtained by integrating the current signal and the inverted current signal when the signal inverting means is operated in the signal integrating means for the same period becomes substantially zero, the normal current signal and the voltage signal are The first power calculated based on the second power calculated based on the inverted current signal and the voltage signal is calculated for the same period, and the sum of the first power and the second power is calculated. By setting it to zero, it is controlled to perform zero point correction of the power value in the power calculation circuit.

  As a result, the zero point of the measured power can be automatically corrected only in the case of smooth AC power without distortion in all waves, so that accurate power measurement can always be performed.

  In the distributed power generation system of the present invention, by providing a signal inversion unit that inverts the positive / negative of the current signal from the current sensor, the electric power after calculation is calculated using the normal current signal and the inverted current signal obtained by operating the signal inversion unit. By making the sum of the values zero, by correcting the deviation of the zero point of the power calculated in the power calculation circuit, the zero point of the measured power can be automatically corrected, so that accurate power measurement can always be performed.

  Furthermore, by providing a signal integration means that integrates the current signal from the current sensor, if a special load in the home, such as a half-wave rectified electric appliance, is used, the zero point is not corrected and the full wave Accurate correction can be performed by correcting the zero point only in the case of smooth AC power without distortion.

Block diagram of a distributed power generation system in Embodiment 1 of the present invention Detailed view and peripheral view of power calculation circuit in embodiment 1 Detected voltage, current and power waveform diagram after calculation in the first embodiment Block diagram of a conventional distributed power generation system

A first invention is a distributed power generation system that is connected to a power system via a plurality of electric wires, and generates a DC power, and converts the DC power generated by the power generation apparatus into AC power. DC / AC power conversion means for supplying to a consumer load, a current sensor for detecting a current of the electric wire on the system side from the consumer load, a voltage detection means for detecting a voltage of the electric wire, and a current from the current sensor The power calculation circuit for calculating the measured power based on the signal and the voltage signal from the voltage detection means, the signal inversion means for inverting the sign of the current signal from the current sensor, and the current signal from the current sensor are integrated Signal integrating means, and at least the power generator, the DC / AC power converting means, and a control means for controlling the signal inverting means, and the control means operates the signal inverting means. The normal current signal and the inverted current signal when the signal inverting means are operated, and when the value obtained by integrating the signal integrating means during the same period is substantially zero, the normal current signal and the A first power calculated based on a voltage signal and a second power calculated based on the inverted current signal and the voltage signal are calculated for the same period, and the first power and the second power are calculated. Is controlled so as to perform zero point correction of the power value in the power calculation circuit. As a result, the zero point of the measured power can be automatically corrected only in the case of smooth AC power with no distortion in all waves, so that accurate power measurement can always be performed.

  In addition to the distributed power generation system of the first invention in particular, the second invention further comprises storage means for storing the contents of the zero point correction of the power value in the power calculation circuit, and the control means includes the power calculation circuit Is stored in the storage means, and the measured power is calculated in the power calculation circuit based on the zero point correction contents of the power value stored in the storage means. is there. Thereby, even if the power of the control means is cut off for some reason and the power is turned off, the contents of the zero point correction of the power value are stored in the storage means, so that accurate power measurement can always be performed.

  In addition to the distributed power generation system of the second invention in particular, the third invention further comprises operation means for sending a signal to the control means, and display means for receiving a signal from the control means, wherein the control The means controls the display means to display the contents of the zero point correction of the power value stored in the storage means in conjunction with the operation command of the operation means. As a result, whenever a serviceman or maintenance worker wants to check, the stored contents for zero point correction and the power value corresponding to the contents can be checked directly, so the current state of the power measurement value Can be grasped.

  According to a fourth aspect of the invention, in particular, the control means according to any one of the first to third aspects controls to perform zero point correction of the power value in the power calculation circuit during a midnight time zone. As a result, zero point correction can be accurately performed in the midnight hours when power consumption is small and power fluctuations are small, and there is no influence from special loads in the home, for example, half-wave rectified appliances. It is possible to correct the zero point in the AC power without distortion.

  In the fifth aspect of the invention, in particular, the control means according to any one of the first to fourth aspects of the invention controls to perform zero point correction of the power value in the power calculation circuit during startup of the power generator. Thereby, since the zero point is corrected from the start command to the start of power generation, it can be sufficiently utilized for the calculation of the measured power during power generation.

  According to a sixth aspect of the invention, in particular, the control means of the fifth aspect of the invention controls to perform zero point correction of the power value in the power calculation circuit every time the power generator is activated. Thus, since the zero point is corrected every time from the start command to the start of power generation, accurate power measurement can be performed during each power generation.

  According to a seventh aspect of the invention, in particular, the control means of the fifth aspect of the invention controls to perform zero point correction of the power value in the power calculation circuit when the power generation device is stopped for a predetermined period or longer. As a result, even if the power generation system stops for a long time and the zero point of power measurement shifts during that time, the zero point is corrected during startup before power generation, so accurate power measurement during power generation is possible It becomes.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
Hereinafter, the distributed power generation system according to Embodiment 1 of the present invention will be described in detail.

  FIG. 1 is a block diagram of a distributed power generation system according to Embodiment 1 of the present invention.

  FIG. 1 illustrates a power system 101, a distributed power generation system 102, and a customer load 104. Here, the power system 101 is a single-phase three-wire AC power source including a U phase, an O phase, and a W phase, and the power system 101 and the distributed power generation system 102 are interconnected at a connection point 103. The consumer load 104 is a device that consumes AC power supplied from the power system 101 or the distributed power generation system 102 in a television, an air conditioner, or the like used in a general household.

  The distributed power generation system 102 includes a power generation device 105, a DC / AC power conversion means 106, a voltage detection means 107, a first current sensor 108a, a second current sensor 108b, a signal inversion means 109, It comprises at least a signal integrating means 110, a power calculation circuit 111, a control means 112, a storage means 113, an operating means 114, and a display means 115.

  Here, the power generation device 105 is configured by a fuel cell or the like and generates DC power.

  The DC / AC power conversion means 106 has a configuration including an insulating transformer, transforms the DC voltage generated by the power generation apparatus 105, and converts it into AC that can be consumed by the consumer load 104.

  The voltage detection means 107 detects the voltage between the U phase and the O phase and between the W phase and the O phase.

  The first current sensor 108a and the second current sensor 108b are attached to the electric wires of the power system 101 by current transformers or the like, and detect the magnitude and positive / negative direction of the current flowing at the attached position (in this embodiment, First current sensor 108a is attached to U-phase interconnection point 103, and second current sensor 108b is attached to W-phase interconnection point 103). Here, the power flowing from the power system 101 to the customer load 104 is positive, and is referred to as a forward current. In addition, the power flowing from the distributed power generation system 102 to the power system 101 is negative, which is called reverse power flow.

  The signal inversion means 109 is composed of a switching element such as an FET, and drives the switching element such as an FET by a pulse output from the control means 112 to thereby output the signal from the first current sensor 108a and the second current sensor 108b. The sign of the current signal can be inverted at the timing of one cycle unit (full wave). Further, when it is determined that the first current sensor 108a or the second current sensor 108b is attached to the electric wire in the reverse direction, the signal inverting means 109 automatically reverses the positive / negative of the current signal and correctly receives power. It is also used to measure power and shares a circuit. Here, the current signal is inverted in units of full wave (one cycle), but the signal from the control means 112 is controlled to finely invert the current signal in units of half wave (half cycle). Also good.

  The signal integrating means 110 is constituted by an integrating circuit, and the current signal from the first current sensor 108a and the second current sensor 108b whose signal is inverted by the signal inverting means 109 is not inverted between the positive and negative of the same period. It integrates a normal current signal.

The power calculation circuit 111 calculates a power value by the product of the voltage value detected by the voltage detection means 107 and the current value detected by the current sensor 108. When correcting the zero point of the power value, the first power calculated based on the normal current signal and the voltage signal and the signal inverting means only when the integral value of the current signal by the signal integrating means 110 becomes zero. The second power calculated based on the inverted current signal and the voltage signal obtained by inverting the polarity of the signal by 109 is calculated for the same period, and the sum of the first power and the second power is calculated to obtain a power value. Is zero. Thereby, the zero point correction of the power value in the power calculation circuit 111 can be performed.

The control unit 112 controls the outputs of the power generation device 105 and the DC / AC power conversion unit 106 based on the power value calculated by the power calculation circuit 111. Further, the polarity of the current signal from the current sensor 108 is inverted by controlling the signal to the signal inverting means 109. In this embodiment, the full wave of the current signal is inverted, but the current signal may be inverted in units of half waves. Then, the zero value of the power value in the power calculation circuit 111 is corrected by setting the power value that is the product of the voltage value from the voltage detection means 107 in the AC power calculation circuit 111 to zero.
The storage unit 113 is composed of a nonvolatile memory such as an EEPROM, and stores the power offset value that has been zero-point corrected in the power calculation circuit 111.

  The operation means 114 is constituted by a tact switch, a membrane switch, or the like, and is a means for a serviceman or maintenance worker to perform a predetermined operation.

  The display unit 115 is configured by an LED such as an LCD or 7 segments, and is a unit that displays the power offset value stored in the storage unit 113 and the power value corresponding to the offset value.

  The operation and action of the distributed power generation system configured as described above will be described with reference to FIGS. 1, 2, and 3. First, the flow from the voltage signal and current signal at the interconnection point 103 to the power calculation and control means 112 in the power calculation circuit 111 will be described.

  FIG. 2 is a detailed diagram of the power calculation circuit 111 for measuring power and a diagram showing its periphery. FIG. 3 also shows (a) the power after calculation in the multiplier 111a in the power calculation circuit 111 based on the voltage signal va and the normal current signal ia at the interconnection point 103 in the case of normal power measurement. Based on the signal wa and the power signal after the filter circuit 111b, and (b) the voltage signal vb and the inverted current signal ib at the interconnection point 103 in the case of zero point correction of the power value, the power calculation circuit 111 FIG. 6 is a waveform diagram of a power signal wb after calculation in the multiplier 111a and a power signal after the filter circuit 111b.

  First, in FIG. 2 and FIG. 3A, in the case of normal power measurement, a voltage signal (v = Vp · sinωt) from the voltage detection means 107 at the connection point 103 through the signal amplification circuit and a signal from the current sensor 108. The current signal (i = Ip · sin ωt) that has passed through the amplifier circuit is first integrated in a multiplier 111a in the arithmetic circuit in the power arithmetic circuit 111, and the power signal after the multiplier (a)-(2) in FIG. It becomes a positive AC signal of zero or more shown in wa, and becomes a DC signal shown in the power signal after (a)-(3) filter circuit in FIG. This is a normal power measurement value. (P = (1 / T) ∫vidt) (T is the period) The power value of this DC signal is amplified by the signal amplifier circuit 111c so that it can be input to the A / D input port of the control means 112. The large range value is input to the large range A / D input port of the control means 112 via the signal amplifier circuit 111d. Further, the value of the small range is input to the small range A / D input port of the control means 112 through the signal amplifier circuit 111e. Here, the power value input to the control unit 112 is stored in the storage unit 113 as needed.

In the power calculation circuit 111, the U-phase power value is calculated from the product of the voltage value between the U-phase and O-phase of the voltage detection means 107 at the connection point 103 and the current value from the first current sensor 108a. The power value of the W phase is calculated from the product of the voltage value between the W phase and the O phase of the voltage detection means 107 at the system point 103 and the current value from the second current sensor 108b, and the U phase and the W phase are added together. Power value. Here, the positive / negative of the current value from the current sensor 108 is calculated as positive in the case of forward flow and negative in the case of reverse flow.

  Next, a procedure for correcting the zero point of the power value will be described. 2B and 3B, when the zero value correction of the power value is performed, the control means 112 sends a signal to the signal inversion means 109 to operate, as shown in FIGS. 3B to 3A. In addition, an inverted current signal ib is generated and output based on the current signal from the current sensor 108. This is composed of one cycle of a normal current signal and one cycle of an inverted current signal, with these two cycles as the minimum unit, and is usually composed of an integral multiple. Therefore, a total of 4 cycles may be provided for each 2 cycles, or a total of 6 cycles may be provided for each 3 cycles.

  Here, the minimum unit of two cycles will be described. The voltage signal vb of the voltage detection means 107 at the interconnection point 103 in the same period as the inversion current signal ib is input to the multiplier 111a in the calculation circuit in the power calculation circuit 111 and integrated (FIG. b)-(2) The AC signal shown in the power signal wb after the multiplier is obtained.

  This power signal wb operates the first power obtained by multiplying one cycle of the voltage signal by one cycle of the normal current signal when the signal inverting means 109 is not operated, and the one cycle of the voltage signal, and the signal inverting means 109. And the second power multiplied by the inverted current signal of one cycle. That is, it is composed of the first power and the second power in the same period (here, one cycle at a time), and the unit of one cycle is the minimum unit. Therefore, the first power for two cycles and the second power for two cycles may be sufficient, and each may be an integer multiple thereof. Then, as this passes through the filter circuit 111b, the power signal becomes 0 [W] as shown in the power signal after the (b)-(3) filter circuit in FIG. In the power calculation circuit 111, the zero point of the calculated power is corrected. The numerical data at this time is stored in the memory of the control means 112 as a zero point.

  However, the numerical data is effective only when the value obtained by integrating the inverted current signal ib in the signal integrating means 110 is substantially zero. The control unit 112 always traces and integrates a signal that is an integral multiple of the inversion current signal ib (two cycles as the minimum unit) in the signal integration unit 110 and determines whether or not the integration value is zero. The consumer load 104 includes a positive half-wave load and a negative half-wave load that are likely to generate high-frequency noise. In that case, even if integrated, it does not become zero, and therefore the sum of the first power and the second power also does not become zero. It becomes possible. In other words, the integration is zero only in the case of smooth AC power with no distortion in all waves. Therefore, only in that case, pawl is applied to correct the zero point of measured power.

  When the power signal is 0 [W], as an example of the zero correction of the power value, for example, it is assumed that the numerical data corresponding to the power 0 [W] is “1050”. In the embodiment, since the standard value corresponding to the power value of 0 [W] is “1024”, 1050−1024 = 26. Here, since the power value corresponding to the numerical data “1” corresponds to “1 [W]”, it is shifted by 26 W. That is, it is recognized that a forward current of 26 [W] is flowing even when the power is 0 [W]. Therefore, the memory of the control unit 112 is rewritten so that the numerical value data of power is “−26” and “1024” corresponds to 0 [W]. Further, the power offset value corresponding to 0 [W] is stored in the storage means 113.

In another case, it is assumed that the numerical data corresponding to power 0 [W] is “990”. Here, 990−1024 = −34, and it is recognized that a reverse power flow of 34 [W] flows even when the power is 0 [W]. Therefore, the memory of the control means 112 is rewritten so that the numerical value data of power is “+34” and “1024” corresponds to 0 [W], and this 0 [W
] Is stored in the storage means 113.

  And based on the content of the zero point correction | amendment of the electric power value which the memory | storage means 113 memorize | stored, the measurement electric power at the time of the normal power generation in the electric power calculation circuit 111 is calculated.

  The correction described above is based on the U-phase power value from the product of the U-phase-O phase voltage value and the current value from the first current sensor 108a, and further from the W-phase-O phase voltage value and the second current sensor 108b. In both phases of the power value in the W phase from the product of the current value, numerical data are respectively obtained and correction is performed.

  As a result, the zero point of the measured power can be automatically corrected only in the case of smooth AC power with no distortion in all waves, so that accurate power measurement can always be performed.

  Then, the control means 112 interlocks with the operation command of the operation means 114 and the contents of the zero point correction of the power value stored in the storage means 113, that is, the power offset value and the power value corresponding to the power offset value described above. At least one of them is controlled to be displayed on the display means 115. A serviceman or maintenance worker can confirm the power offset value at that time and the power value corresponding to the offset value as numerical values on the display means 115 by operating the switch of the operation means 114, which is effective for maintenance and repair. It is.

  In addition, the control means 112 controls to perform zero point correction of the power value in the power calculation circuit 111 in the midnight time zone. The “midnight time zone” is 12 o'clock to 3 o'clock, more preferably 1 o'clock to 2 o'clock. In the midnight time zone, power consumption is small and fluctuations in power are small, which is preferable for executing zero point correction. In addition, the consumer load 104 is always energized only by a general refrigerator or the like, and a special load, specifically, a positive half-wave load or a negative half-wave load that easily generates high-frequency noise. It can be said that it is preferable for performing zero point correction because the probability that a load that is half-wave rectified or a load whose waveform is deformed is low. In addition, the case where the positive half wave and the negative half wave are not slightly the same is not appropriate. In any case, it is limited only when the value obtained by integrating the inverted current signal ib in the signal integrating means 110 becomes substantially zero. Therefore, in the “midnight time zone”, it is possible to perform the zero point correction in the smooth AC power without distortion in all the waves.

  In addition, the control unit 112 controls the power value to be corrected in the power calculation circuit 111 while the power generation apparatus 105 is activated. During start-up from the start command from the control means 112 until the start of power generation, that is, after the start command, ignition and temperature rise are performed by a fuel processor (not shown), the temperature conditions of each part are adjusted, By correcting the zero point of the power until the transition to, power information necessary for controlling the power generation device 105 and the DC / AC power conversion means 106 can be acquired in advance, and the measured power during power generation can be calculated. Can be used.

  Further, the control unit 112 performs control so as to perform zero point correction of the power value in the power calculation circuit 111 every time the power generation apparatus 105 is started. Since the zero point is corrected every time during start-up from the start command from the control means 112 to the start of power generation, accurate power measurement can be performed in each power generation.

  Further, the control unit 112 performs control so as to perform zero point correction of the power value in the power calculation circuit 111 when the power generation apparatus 105 is stopped for a predetermined period or longer. Even if the power generation system stops for a long time due to the absence of a user for a long time and the zero point of power measurement shifts during that time, the zero point can be corrected during startup before power generation. Accurate power measurement during power generation can be performed with peace of mind.

  As described above, the distributed power generation system according to the present invention includes the signal inversion unit that inverts the polarity of the current signal from the current sensor, so that the normal current signal and the inversion current obtained by operating the signal inversion unit are provided. The sum of power values after calculation is set to zero by the signal. Thereby, since the zero point of the measured power can be automatically corrected by correcting the deviation of the zero point of the power calculated in the power calculation circuit, the fuel cell power generation system, the solar power generation system, The present invention can also be applied to uses such as a distributed power generation system such as a wind power generation system and a solar thermal power generation system.

DESCRIPTION OF SYMBOLS 101 Electric power system 102 Distributed type power generation system 103 Connection point 104 Consumer load 105 Power generation device 106 DC / AC power conversion means 107 Voltage detection means 108a First current sensor 108b Second current sensor 109 Signal inversion means 110 Signal integration means 111 Power calculation circuit 112 Control means 113 Storage means 114 Operation means 115 Display means

Claims (7)

A distributed power generation system that is connected to a power system via a plurality of electric wires,
A power generator for generating DC power;
DC AC power conversion means for converting the DC power generated by the power generator into AC power and supplying it to a consumer load;
A current sensor for detecting a current of the electric wire on the system side from the load in the consumer;
Voltage detecting means for detecting the voltage of the electric wire;
A power calculation circuit for calculating measured power based on a current signal from the current sensor and a voltage signal from the voltage detection means;
Signal inversion means for inverting the polarity of the current signal from the current sensor;
Signal integration means for integrating the current signal from the current sensor;
Control means for controlling at least the power generator, the DC / AC power conversion means, and the signal inversion means;
With
The control means includes
When the value obtained by integrating the normal current signal when the signal inverting means is not operated and the inverted current signal when the signal inverting means is operated and the signal integrating means is integrated for the same period is substantially zero, The first power calculated based on the normal current signal and the voltage signal and the second power calculated based on the inverted current signal and the voltage signal are calculated for the same period, and the first power is calculated. A distributed power generation system that performs control to perform zero point correction of a power value in the power calculation circuit by setting a sum of power and the second power to zero. The storage means further stores the contents of the zero point correction of the power value in the power calculation circuit, and the control means stores the contents of the zero point correction of the power value in the power calculation circuit in the storage means. The distributed power generation system according to claim 1, wherein the measurement power in the power calculation circuit is calculated based on the contents of the zero point correction of the power value stored in the means. Operation means for sending a signal to the control means, and display means for receiving a signal from the control means, the control means memorize in the storage means in conjunction with an operation command of the operation means The distributed power generation system according to claim 2, wherein control is performed so as to display on the display means the contents of the zero point correction of the measured power value. The distributed power generation system according to any one of claims 1 to 3, wherein the control unit performs control so as to perform zero point correction of a power value in the power calculation circuit in a midnight time zone. 5. The distributed power generation system according to claim 1, wherein the control unit performs control so as to perform a zero point correction of a power value in the power calculation circuit during startup of the power generation device. The distributed power generation system according to claim 5, wherein the control unit performs control so as to perform zero point correction of a power value in the power calculation circuit every time the power generation device is activated. The distributed power generation system according to claim 5, wherein the control unit performs control so as to perform a zero point correction of a power value in the power calculation circuit when the power generation device is stopped for a predetermined period or longer.

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