JP4439350B2 - Private power generation system - Google Patents

Description

  The present invention relates to an in-house power generation system in which an in-house power generation means is connected to a system and reversely flows.

  A conventional private power generation system will be described with reference to FIG.

  As shown in the figure, the private power generation system J includes a private power generation device 1 that outputs generated power such as a solar power generation device as alternating current power, and a distribution board that distributes the private power generation device 1 and the commercial power system 3 to alternating current loads. 2, current sensors CTa and CTb that detect the current of the commercial power system 3, an operation storage unit 17 that performs calculation and storage based on information obtained from the current sensors CTa and CTb, and an output from the operation storage unit 17 And a display unit 10 for displaying the information.

  The AC power generated by the private power generator 1 is connected to the commercial power system 3 via the distribution board 2 so that a reverse power flow is possible.

  The commercial power system 3 is a single-phase three-wire AC power source consisting of a U phase, an O phase, and a W phase. The power generated by a solar cell or wind power generator is converted by a power conditioner and used as AC power. Together with the private power generator 1 that can be used, the branch disconnector 4 in the distribution board 2 can supply power to the AC load.

  In the distribution board 2, a current sensor CTa for detecting a U-phase current and a current sensor CTb for detecting a W-phase current are respectively connected between the branch disconnector 4 and the commercial power system 3. Attached to phase wire.

  In addition, the private power generation device 1 may be directly connected to the commercial power system 3 via the earth leakage breaker without using the distribution board 2.

  The calculation storage unit 17 calculates the power by the addition calculation unit 14 that receives the current detection signals 6a and 6b from the current sensors CTa and CTb, and the voltage detection signal 5 that detects the calculation result of the addition calculation unit 14 and the voltage of the commercial power system. And a power calculation unit 18 for performing

  Hereinafter, how the current detection of the commercial power system is performed will be described.

  The current detection signal 6a detected by the U-phase current sensor CTa and the current detection signal 6b detected by the W-phase current sensor CTb are sent to the addition calculation unit 14 in the calculation storage unit 17, respectively. The addition calculation unit 14 adds up the waveform signals of the U-phase and W-phase current sensors and transmits the sum to the power calculation unit 18.

  The power calculation unit 18 receives the waveform signals of the U-phase and W-phase current sensors added by the addition calculation unit 14 and the voltage waveform signal 5 of the commercial power system 3 to perform power calculation. The value of the calculation result and the positive / negative sign data are output to the display unit 10 to display the power and the direction of selling / buying power (for example, see Patent Document 1).

In addition, a display device that measures and displays power consumption generally consumed in the home has been proposed regardless of the grid connection of the private power generator (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 11-225440 JP-A-10-123185

  However, any of the above-described techniques has been shown to attach a CT (current sensor) to the main line of the system as a current detection means for power calculation (in the case of a general house, there are many single-phase three-wire systems, It is necessary to attach two CTs, one for each of the W phase and U phase.) However, the direction of CT installation is unclear, and CT depends on the direction of the current through the wire that passes through. Since positive / negative (phase with respect to voltage in the case of alternating current) is determined, particularly when the power display device is installed later, a split type clamp sensor that can be retrofitted is attached to an existing distribution board or the like.

  However, correct power calculation results cannot be obtained unless the orientations of the two CTs to be attached and the polarity of the AC phase at the time of voltage detection are all properly installed. For example, if one of the CTs is installed in the opposite direction, the currents cancel each other and the calculation result is close to zero. If the voltage detection phase is reversed and / or two CTs are installed in the opposite direction, the calculation result Positive and negative results are reversed, and the direction of power selling / buying is judged as a reversed result.

  When measuring power selling / purchasing power in this way, whether it is in the power selling state or in the power buying state is determined by the phase of the voltage and current to be detected, so the polarity of the phase when detecting the system voltage and Correct measurement and power calculation cannot be performed unless the mounting direction of the CT for detecting current is specified.

  In addition, when performing CT installation and electrical wiring work for the power supply at the site, detailed explanation is required for the construction work, and operation confirmation is indispensable. It is difficult to work without making a mistake in the direction of CT or the like.

  Furthermore, these are based on the assumption that there is only one type of private power generator. Regardless of the presence or absence of reverse power flow, if another power generator is installed, the direction of current flow depends on the state of the load. If this is the case when the orientation of the CT at the time of system installation is matched, the CT will be installed in the reverse direction. If the construction is completed as it is, and then the load balance state or the power generation state of the in-house power generator changes, and the current flow direction is further reversed (returns to the normal direction), the CT is correctly measured and This means that power calculation is not possible.

  This phenomenon will be described with reference to FIGS. It is assumed that the load capacities of the U phase and the W phase are unbalanced.

  The following a) to d) will be described with reference to FIGS. 5, 6, 7, and 8, respectively.

  a) When the private power generation apparatus 1 is stopped and the private power generation apparatus 19 provided therewith is also stopped.

  In the U-phase current sensor CTa, it is assumed that the direction in which current flows from the commercial power system 3 to the load side is the power purchase direction, and in the W-phase current sensor CTb, the direction in which current flows from the load side to the commercial power system 3 is the power purchase direction. . Assuming that the U-phase load 41a consumes 300 W and the W-phase load 41b consumes 900 W, since the private power generation devices 1 and 19 are stopped, the directions in which the U-phase and W-phase currents flow are both in the power purchase direction.

  b) When the private power generation device 1 generates power and the private power generation device 2 attached thereto stops.

  Assuming that the U-phase load 41a consumes 300W, the W-phase load 41b consumes 900W, and the private power generation device 1 generates 1500W, the direction in which the U-phase current flows is the power selling direction, and the direction in which the W-layer current flows is the buying direction. It becomes.

  c) When the private power generation apparatus 1 generates power and the private power generation apparatus 2 to be provided is also generating power.

  Assuming that the U-phase load 41a consumes 300W, the W-phase load 41b consumes 900W, the private power generation device 1 uses 1500W power generation, and the private power generation device 19 uses 1000W power generation, the U-phase / W-phase current flows in both directions. Direction.

  d) When the private power generation apparatus 1 is stopped and the private power generation apparatus 2 installed is generating power.

  Assuming that the U-phase load 41a consumes 300W, the W-phase load 41b consumes 900W, and the private power generator 19 generates 1000W, the direction in which the U-phase current flows is the power selling direction, and the direction in which the W-layer current flows is the power purchase direction. It becomes. For a power generation of 1000 W, the total consumption is 1200 W (= 300 W + 900 W), which should be in the direction of consumption, but in this case, the direction of the U-phase current is reversed.

  In the case of the pattern d), the direction in which the U-phase current flows is reversed from the original direction, and if CT is installed in this state, the determination is erroneous.

  The present invention has been made in view of the above-described conventional problems, and the purpose of the present invention is to enable installation work that does not depend on the connection polarity of the voltage detection wiring and in particular the mounting direction of the current sensor of the wire mounting type. It is an object of the present invention to provide a highly reliable private power generation system which can perform sensor installation and power supply wiring work easily and quickly, and which displays a correct power even when another power generation apparatus is installed.

In order to solve the above problems, according to the private power generation system of the present invention, in the private power generation system in which the private power generation means is connected to a single-phase three-wire system and reversely flows, power selling power and purchased power are measured. for the product of a current sensor for detecting the magnitude and sign of the direction of the current, voltage detection means for voltage detection, the value of the voltage detected by the value of the current detected by said current sensor and said voltage detecting means and power sale-purchased electric power calculating means for calculating a, a power generation state detecting means for detecting a power generation information before Symbol private power generation unit, based on the power information detected from the power generation state detecting means, the power sale, purchased power Sign determination means for determining a positive / negative sign based on the calculation result of the power calculation means, and a sign inversion means for inverting the positive / negative sign based on the calculation result of the power selling / buying power calculation means based on the determination result of the sign determination means And before And display means for displaying on the basis of power selling and / or purchased power to positive and negative calculation result and the reference numerals have been determined by the sign determining means, said code determining means, the power generation information no power generation state or generator When the calculation result of the power selling / purchasing power calculation means is a negative sign, the calculation result sign correction determination is performed and the correction determination is performed a plurality of times. Outputs a request signal.
Thereby, the polarity of the phase when detecting the system voltage and the mounting direction of the current sensor for detecting the current are automatically discriminated and corrected, and correct power display can be performed even when another power generator is installed. .

According to the in-house power generation system in which the in- house power generation means of the present invention is connected to a single-phase three-wire system and reversely flows , the magnitude of the current and the positive / negative direction are detected for measuring the electric power sold and the electric power purchased. A current sensor , a voltage detection means for voltage detection, a power sale / buy power calculation means for calculating a product of a current value detected by the current sensor and a voltage value detected by the voltage detection means , determining a power generation state detecting means for detecting a power generation information before Symbol private power generation unit, based on the power information detected from the power generation state detecting means, a positive or negative sign according to the calculation result of the power selling, purchased electric power computing means Based on the determination result of the sign determination means, the sign determination means, the sign inversion means for inverting the positive / negative sign based on the calculation result of the power selling / buying power calculation means, and the positive / negative sign is determined by the sign determination means the calculation result you were And display means for displaying the power selling and / or purchased power based on fine said code, said code determining means, the power generation information is no power generation state or the power generation stop state and the power selling, purchased electricity power When the calculation result of the calculation means is a negative sign, the correction detection of the sign of the calculation result is performed, and a correction request signal is output when the correction determination is performed a plurality of times. The installation work can be done regardless of the connection polarity and current sensor mounting direction, and the direction of selling or buying power can be changed even if the voltage detection phase is reversed and / or any or all of the current sensors are reversed. As a reverse result, calculation / display and the like can be prevented, and a highly reliable private power generation system capable of displaying correct power even when another power generation device is provided can be provided.

  Also, when installing the current sensor and the electrical wiring work of the power supply at the site, it is not necessary to give a detailed explanation of the construction work or to manage it without making a mistake according to the instructions, so the time required for construction can be shortened At the same time, it is possible to reduce the inspection process of whether or not the construction is correctly performed.

  Furthermore, when the current sensor is installed, the direction of the current is set to the correct direction regardless of the load status, whether another power generator is installed, whether another power generator is added at a later time, and the power generation status. It can be corrected.

  Embodiments of a private power generation system according to the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a circuit configuration diagram showing an outline of a private power generation system S according to the present invention.

  As shown in the figure, the private power generation system S includes a private power generation device 1 that is a private power generation means for outputting generated power as alternating current power by a solar power generation device or a wind power generation device, and the private power generation device 1 or commercial power system 3. Distribution board 2 that distributes current to AC load, current sensors CTa and CTb that detect the current of commercial power system 3, signals obtained from current sensors CTa and CTb, and signals obtained from lead lines that are voltage detection means The calculation storage unit 7 includes a power sale / purchase power calculation means for performing calculation and storage, and a display unit 10 for displaying information output from the calculation storage unit 7.

  Here, after the power generation amount of the private power generator 1 is equal to or less than a predetermined amount in the calculation storage unit 7 and the calculation result of the power selling / buying power calculation means is equal to or greater than a predetermined amount, The sign of the calculation result of the power selling / purchasing power calculating means is reversed by the sign determining unit 16 which is an inverting means.

  The AC power generated by the private power generator 1 is connected to the commercial power system 3 via the distribution board 2 so that a reverse power flow is possible.

  The commercial power system 3 is a single-phase three-wire AC power source composed of a U-phase, an O-phase, and a W-phase. The power generated by a solar cell or a wind power generator is converted into AC power by a power conditioner that is a power converter. Along with the private power generator 1 that can be used, power is supplied to an AC load or the like by the branch disconnector 4 in the distribution board 2.

  In the distribution board 2, a current sensor CTa for detecting a U-phase current and a current sensor CTb for detecting a W-phase current between the branch disconnector 4 and the commercial power system 3 are respectively U-phase and W-phase power lines. Is attached. In addition, the private power generation device 1 may be directly connected to the commercial power system 3 via the earth leakage breaker without using the distribution board 2.

  The storage calculation unit 7 includes the power selling / purchasing power calculation means and the sign determination unit 16. That is, the memory calculation unit 7 includes a power calculation unit 8a that receives the current detection signal 6a from the current sensor CTb, a power calculation unit 8b that receives the current detection signal 6b from the current sensor CTa, and power calculation units 8a and 8b. An addition calculation unit 14 that receives the calculation results from the non-volatile memory 15 that stores the positive and negative signs of the power calculation units 8a and 8b, and a code determination unit 16 that receives the operating state and the stop state of the private power generator 1. Consists of.

  The manner in which current detection of the commercial power system is performed will be described below.

  The current detection signal 6a detected by the U-phase current sensor CTa is transmitted to the power calculation unit 8a of the calculation storage unit 7, and the current detection signal 6b detected by the W-phase current sensor CTb is the power of the calculation storage unit 7. It is transmitted to the calculation unit 8b.

  A voltage detection signal 5 for detecting the voltage of the commercial power system is input to the power calculation units 8a and 8b, and power calculation is performed independently together with the voltage information.

  In the present embodiment, a voltage waveform is taken in for each phase as voltage information. Actually, the voltage is smaller in the difference between phases as the current is used, and the other is calculated by the same waveform. Needless to say, the present invention is not limited to this, and a method of reading both current and voltage may be used.

  When supplying power to the commercial load through the branch disconnector 4, supplying all power from the private power generator 1, performing reverse power flow (assuming negative), and supplying power from the commercial power system 3 With (assumed to be positive), a phenomenon occurs in which the phase of the current with respect to the voltage is reversed at the location where the current sensors CTa and CTb are installed.

  Therefore, there are cases where the power calculation result based on the waveform signals from the current sensors CTa and CTb is positive (power consumption) and negative (reverse power flow). The positive and negative signs of the calculation result are individually stored in a storage element such as the nonvolatile memory 9.

  The positive and negative signs stored in the nonvolatile memory 9 are corrected based on power generation information such as operation / stop from the private power generation apparatus 1 based on sign determination described later, and then sent to the addition calculation unit 14 to perform addition calculation. The value of the calculation result and the positive / negative sign data are output to the display unit 10 to display the power and the direction of selling / buying power.

  Next, the power calculation code determination method according to the present invention will be described with reference to FIG.

  It should be noted that the display on the display unit 10 displays power purchase if the sign obtained from the calculation storage unit 7 is positive (plus), and sells power if it is negative (minus).

    When the installed private power generation apparatus is limited to the private power generation apparatus 1, when the private power generation apparatus 1 is not generating power after the installation of the private power generation system of the present invention, reverse power flow (power sale) is performed. Is not possible.

  Using this, when the power generation information sent from the private power generation device 1 to the code determination unit 17 is a signal notifying the communication data absence state (no power generation state) or the power generation stop state, the current sensors CTa and CTb The detected current detection signal 6 (6a, 6b) is calculated by each power calculation unit 8 (8a, 8b).

  In the case where the absolute value of each result is a predetermined amount or more (for example, 0.1 kW or more), for example, when the result of the power calculation unit 8a has a negative sign, the current sensor CTb is installed in the reverse direction. Since it is determined that the sign inversion of the power calculation unit 8b occurs in the non-volatile memory 15 of the code determination unit 17, it is stored that it is necessary to invert the code.

  After this case, when data with a negative sign is output from the power calculation unit 8a, the data with a positive sign is output when the data with a negative sign is output, and when data with a positive sign is output. A signal for requesting correction is output to the addition operation unit 14 so as to convert it into a sign, and the sign reversal in the current direction due to the reverse installation of the current sensor CTa is correctly corrected.

  Similarly, it is possible to cope with the case where the sign inversion of the power calculation unit 8b occurs when the current sensor CTb is installed in the reverse direction.

  Note that this determination only needs to be made once at the time of installation and does not need to be determined frequently at all times. Therefore, the absolute value of the measured power selling / purchasing power is set to a predetermined amount or more (for example, 0.1 kW or more). ing. In addition, when the current sensor is installed in a normal direction, the result of the power calculation unit is positive (plus), but there is no need for inversion. I decided not to do it. In addition, considering the possibility of erroneous installation being repaired during maintenance or the like, conditions such as only at the first power-on or every other hour may be provided for the current sensor determination.

  If the circuit has a sufficient processing speed, as shown in FIG. 3, the sign determination unit 16 is inserted between the power calculation units 8a and 8b and the addition calculation unit 14 to Then, the sign determination / reversal process may be performed in real time and transmitted to the addition operation unit 14.

  In the example of the initial setting described above, in an ordinary household, an AC load is connected almost without exception, and when the private power generator does not generate power, the power consumption from the commercial power system side occurs. Although the connection process of the AC load is omitted by using, it is preferable to connect the AC load in an operating state in order to reliably complete the setting.

  Furthermore, when other private power generators are installed, depending on the power generation status of both power generators and the load balance of each connected phase, the current flow direction may be temporarily reversed as described above. There is. If correction by automatic determination is performed at the timing when the current direction is reversed, an incorrect determination may be made, and power display may not be performed correctly.

  Therefore, in this determination of sign inversion, the result is not reflected immediately, but a determination is made a plurality of times to reflect the result.

  FIGS. 9A and 9B are flowcharts showing a method of determining the direction of the current sensor according to this embodiment.

  Hereinafter, the direction determination method of the current sensor according to the present embodiment will be described with reference to FIG.

  The flow shown in a) and b) of FIG. 9 is executed during the sign inversion determination timing in FIG.

  First, in the flow of step A, it is verified whether or not the direction of power purchase obtained by the sign determination unit 16 this time is the same as the direction of power purchase currently stored in the nonvolatile memory 9. The different direction detection counter is increased (+1) and the process proceeds to step B. If the same, the different direction detection counter is cleared and the verification of step A is repeated.

  In step B, it is verified whether the different direction detection counter is greater than or equal to the specified number of times, and if it is less than the specified number of times, the process proceeds to verification in step A, and if it is greater than or equal to the specified number of times, the power purchase direction is reversed. Therefore, the reversed power purchase direction is stored in the nonvolatile memory 9, the different direction detection counter is cleared, and the process proceeds to step A verification.

  In addition, by changing the cycle for performing the determination of this flow and the specified number of times of different direction detection counter determination, the direction of the current sensor can be reversed at any time in consideration of the operation characteristics of the private power generator 19 provided. You can do it.

  In addition, when the power is turned on for the first time at the time of installation, it is necessary to determine the correct direction at an early stage.Therefore, only when the power is turned on for the first time at the time of installation, it can be handled by setting the specified number of different direction detection counter judgments to a small value. is there.

  In this way, after being corrected based on the sign determination, it is sent to the addition calculation unit 14 to perform the addition calculation, and is output to the display unit 10 as the value of the calculation result and the positive / negative code data to display the power and sell the power.・ Because the direction of power purchase can be displayed, the correct power calculation result can be obtained and displayed regardless of the mounting direction of the current sensor and the polarity of the AC phase when detecting the voltage. It becomes possible to do.

  In the case where another private power generator is installed, the direction of current flow is temporarily reversed at the time of installation, and even if the power purchase direction is set as the wrong direction, the direction of current flow thereafter When is returned to the normal direction, the direction of the current sensor can be corrected to the correct direction.

  In addition, even if another private power generator is installed, and the direction of current flow is temporarily reversed during normal operation, the direction of the current sensor is not reversed immediately. It is possible to avoid and maintain a correct power display.

  In the present embodiment, the case where the calculation storage unit 7 is installed outside the private power generation device 1 has been described as an example. However, the present invention is not limited to this, and the calculation storage unit 7 is provided inside the private power generation device 1. In this case, the same configuration may be used.

  Further, in the present embodiment, the power generator installed together is a single-phase 200V output device, but the present invention can also be applied to a single-phase three-wire 100 / 200V output device.

  Furthermore, in the description of the flowchart, when the power purchase direction is the same in step A, the different direction detection counter is cleared. However, the present invention can also be applied by lowering the counter.

1 is a circuit configuration diagram schematically illustrating an embodiment of a power display device according to the present invention. It is a figure which illustrates typically the power calculation code determination method of the power display apparatus which concerns on this invention. It is a circuit block diagram which illustrates typically other embodiment of the electric power display apparatus which concerns on this invention. It is a circuit block diagram which illustrates typically the embodiment of the conventional private power generation device. It is a circuit block diagram which illustrates typically the direction through which the electric current of each phase in case another private power generation device is attached. It is a circuit block diagram which illustrates typically the direction through which the electric current of each phase in case another private power generation device is attached. It is a circuit block diagram which illustrates typically the direction through which the electric current of each phase in case another private power generation device is attached. It is a circuit block diagram which illustrates typically the direction through which the electric current of each phase in case another private power generation device is attached. a) and b) are flowcharts showing a direction determination method of the current sensor according to the present embodiment.

Explanation of symbols

1: Private power generator 2: Distribution board 3: Commercial power system 4: Branch disconnector 5: Voltage detection signal 6a, 6b: Current detection signal 7: Calculation storage unit 8a, 8b: Power calculation unit 9: Non-volatile memory 10 :display
14: Addition calculation unit 15: Non-volatile memory 16: Sign determination unit 17 Calculation storage unit 18: Power calculation unit 19: In-house power generators 41a and 41b: Load CTa, CTb: Current sensor J: Power display system S: Power display system

Claims (1)

In the private power generation system that reverse power flows by connecting the private power generation means to the single-phase three-wire system ,
A current sensor for detecting the magnitude and sign of the orientation of the current,
And the voltage-detection means,
And power sale-purchased electric power computing means for computing the product of the voltage value detected in the previous SL current sensor in the detected current value and said voltage detecting means,
A power generation state detecting means for detecting a power generation information before Symbol private power generation means,
Based on the power generation information detected from the power generation state detection means, a sign determination means for determining a positive / negative sign according to a calculation result of the power selling / buying power calculation means,
Based on the determination result of the sign determination means, sign inversion means for inverting the positive / negative sign according to the calculation result of the power selling / buying power calculation means,
Display means for displaying power sale and / or power purchase based on the calculation result in which the positive / negative sign is determined by the sign determination means and the sign ;
Equipped with a,
The sign determination means determines whether the calculation result sign is correct when the power generation information is in a no power generation state or a power generation stop state, and the calculation result of the power selling / buying power calculation means is a negative sign. And a private power generation system that outputs a correction request signal when the correction determination is made a plurality of times.

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