JP2008259400A - Independent operation detection method, controller for detecting independent operation of distributed power supply, independent operation detection device, and distributed power supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To satisfy ΔV10 to eliminate a flicker problem, while detecting an independent operation at high speed. <P>SOLUTION: A method, which detects whether or not a distributed power supply is separated from an electric power system and is performing independent operation by causing power fluctuation to the power system, includes a step in which electric energy (power fluctuation value) which is to be injected to cause the power fluctuation to the power system is calculated based on a period deviation, which is a deviation of the current system period and the past system period. In this step, a voltage variation portion ΔVn in each fluctuating frequency fn of the power system is converted into a variation value ΔV10 of 10 Hz in a flicker visibility curve and the calculation above is carried out in such a manner that the converted fluctuation value ΔV10 satisfies a permissible amount, which is a judgment criterion for taking a countermeasure against the flicker. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an isolated operation detection method for detecting whether or not a distributed power source is isolated from a power system based on various power fluctuations such as reactive power injected into the power system, and an isolated operation of the distributed power source. The present invention relates to a detection control device, an isolated operation detection device, and a distributed power supply system.

  Conventionally, such an isolated operation detection device includes an inverter circuit that converts DC power of a distributed power source into AC power of a power system, and supplies the converted AC power to a load in linkage with the power system. The inverter output waveform of this inverter circuit is distorted to produce fluctuations in the output frequency during single operation, and the single operation is detected by detecting the frequency fluctuation caused by this distortion or the fluctuation caused by the frequency fluctuation. It is known (see, for example, Patent Document 1).

  In addition, according to the isolated operation detection device of Patent Document 1, in order to keep the system voltage and system frequency constant on the power system side, the amount of power generated by the power station on the power system side according to the load fluctuation of the consumer. However, when this low-frequency fluctuation occurs, a small frequency change (deviation amount change) occurs, so reactive power is injected between the distributed power supply and the power system. Since the dead zone range is set so as not to occur, it is possible to reliably prevent the influence of the distributed power source upon the system when the low-frequency fluctuation occurs.

  Further, according to the conventional isolated operation detection device, the isolated operation detection time from the isolated operation occurrence to the isolated operation detection requires 0.5 seconds to 1.0 seconds. For example, a high-speed detection technique that shortens within 0.1 seconds is desired.

  Therefore, in order to meet such a demand, the present applicant has devised an isolated operation detection device that detects an isolated operation of a distributed power source at a high speed with an isolated operation detection time within 0.1 seconds (for example, a patent). Reference 2).

  Hereinafter, a distributed power supply system including an isolated operation detection device according to the applicant's invention will be described with reference to FIG. FIG. 11 is a block diagram showing a schematic configuration inside the distributed power supply system according to the present embodiment. A distributed power supply system 10 shown in FIG. 11 generates DC power, for example, a distributed power supply 12 such as a solar power generator or a gas engine generator, and a power system 14 connected to the distributed power supply 12. A power conditioner device 16 disposed between the distributed power source 12 and the power system 14 and having a power conversion function, and a power conditioner device 16 disposed between the power conditioner device 16 and the power system 14. And the power conditioner device 16 converts the DC power generated by the distributed power source 12 into the AC power of the power system 14 through the power conversion function. The converted AC power is supplied to a load outside the figure such as general home appliances.

  The isolated operation detection device 18 includes interconnection relays 20 and 22, a control device 24, an inverter control unit 26, an inverter 28, and a current detector 30.

  The control device 24 will be described with reference to FIG.

  The control device 24 performs a system operation determination unit 34 for measuring the system period from the system voltage from the power system line 32, and makes an independent operation determination from the measured value of the system period measurement unit 34, and connects the interconnection relays 20 and 22 according to the determination. The isolated operation determination unit 36 that performs on / off control, and the moving average value of the current system cycle and the moving average value of the past system cycle are calculated from the measured values of the system cycle measuring unit 34, and the deviation of the system cycle is calculated from the calculated values. A cyclic deviation calculating unit 38 for calculating a cyclic deviation, a reactive power calculating unit 40 for calculating a reactive power amount (power fluctuation amount) to be injected into the power system from the cyclic deviation of the cyclic deviation calculating unit 38, and An output current control unit 42 that outputs an output current control signal to the inverter control unit 26 according to the calculation output.

  The period deviation calculating unit 38 is a current moving average calculating unit 38a that calculates a moving average value of a current system period, a past moving average calculating unit 38b that calculates a moving average value of a past system period, and both of these calculated values. It is comprised from the period deviation calculating part 38c which calculates the period deviation which is a deviation of a system | strain period.

  The system period measurement unit 34 sequentially measures the system period of the power system 14 from the system voltage in units of measurement periods, for example, 5 m sand. In addition, when the system period of the electric power system 14 is 50 Hz (one system period is 20 milliseconds), the measurement period unit is desirably 1/3 or less of the system period of the electric power system 3, for example, 5 milliseconds unit.

  In the period deviation calculating part 38, based on the system period of the 5 m sand unit sequentially measured by the system period measuring part 34, the moving average value of the system period corresponding to the continuous predetermined moving average time, for example, 40 milliseconds is sequentially calculated. Is. The predetermined moving average time is preferably set to 40 ms, for example, because it is longer than one cycle of the system cycle, for example, 20 ms and as short as possible for a desired detection speed, for example, 100 ms.

  FIG. 13 is an operation explanatory diagram related to the system cycle measuring unit 34 and the cycle deviation calculating unit 38. C0 shown in FIG. 13 is a system cycle currently measured by the system cycle measuring unit 34, C1 is a system cycle measured 5 ms before, and Cn is a measured value of the system cycle n * 5 ms before. Therefore, the period deviation calculating unit 38 calculates the latest moving average value in units of 5 milliseconds by moving average the system period for 40 milliseconds from C0 to C7.

  The past moving average value is calculated by moving average the system cycle for 40ms from C40 to C47 200msec before C0, and calculating sequentially in 5msec units when the latest moving average value of C0 to C7 is used. is there. The current period deviation is calculated by the past moving average value (C40 to C47) and the latest moving average value (C7 to C0).

  The reactive power amount calculation unit 40 calculates the reactive power amount based on the periodic deviation calculated by the periodic deviation calculation unit 38 using the characteristic of the reactive power amount (power fluctuation injection amount) versus the periodic deviation shown in FIG. The reactive power amount is notified to the output current control unit 42.

  The reactive power amount one-cycle deviation characteristic shown in FIG. 14 is a range in which when the period deviation is small, the change rate of the reactive power amount with respect to the change of the periodic deviation is reduced, that is, the slope of the characteristic line L1 is reduced to lower the isolated operation detection sensitivity. The low sensitivity band range R1 is high, and when the period deviation is large, the high sensitivity is the range in which the change rate of the reactive power amount with respect to the change of the period deviation is increased, that is, the inclination of the characteristic line L1 is increased to increase the isolated operation detection sensitivity. Band ranges R21 and R22 are set.

  The reactive power amount is decreased in the high sensitivity band range R21, the reactive power amount is increased in the high sensitivity range R22, and the change rate of the reactive power amount with respect to the periodic deviation is set small in the low sensitivity range R1. It is.

  That is, reactive power can be injected even in the low sensitive range R1 with a small period deviation to detect the isolated operation of the distributed power source 12, and the change rate of the reactive power can be set to the high sensitive range R21, R21, By making it smaller than in the case of R22, it is possible to reliably prevent the influence of the distributed power source on the system without being affected by the slow fluctuation of the system voltage.

  The distributed power supply system described above is the same as the system shown in FIG. In this system, an independent operation detection device is built in the power conditioner 16. Portions corresponding to those in FIG. 11 are denoted by the same reference numerals.

  In the isolated operation detection in the distributed power system described above, the power fluctuation injection method was the reactive power fluctuation method, but other methods such as the active power fluctuation method, the harmonic injection method, etc. (power fluctuation method) ) Can be implemented in the same manner.

  On the other hand, in such an isolated operation detection by the power fluctuation method, the system cycle is constantly fluctuating due to the fluctuation of the load connected to the power system, the influence of the system impedance, and the like. For example, ± 0.03 Hz at 50 Hz. In addition, depending on the site, there may be a large system cycle fluctuation (for example, ± 0.1 Hz or more), for example, several times in 10 seconds. Further, in order to realize high-speed detection of isolated operation, the rate of change of the reactive power amount in the high sensitive range R21, R22 of FIG. 14 is increased, that is, the slope of the characteristic line L1 is increased. For this reason, as a result of the reaction of the fluctuation control device 24 of the system cycle in the steady state and outputting reactive power, depending on the reactive power amount and frequency, an allowable value of flicker (periodic fluctuation of voltage) (ΔV10 described below) ) Is assumed.

  Flicker may cause a flicker of a load connected to the power system into which such power fluctuations are injected, for example, flickering of a fluorescent lamp, malfunction of a microcomputer, and inability to control the rotation of a motor. In addition, flicker causes flickering of illumination due to fluctuation of the effective voltage value in the voltage system, which is an important problem in power quality. As one of the management indexes, there is ΔV10 as shown by the equation (1).

式（１）において、ΔＶｎは例えば図１６で示すように、電圧動揺を周波数分析した結果得られる変動周波数ｆｎの電圧変動成分の振れ（実効値）を示し、ａｎは図１７で示すちらつき視感度曲線における１０Ｈｚを１としたときの変動周波数ｆｎに対応するちらつき視感度係数を示す。ΔＶ１０はちらつき視感度曲線における１０Ｈｚの変動値である。このΔＶ１０は所定の許容値と比較され、許容値以下ならば電力品質良好と判断し、許容値以上ならば不良と判断する。
特開平９−３２２５５４号公報 特願２００６−２２５０１６号明細書および図面

In equation (1), ΔVn represents the fluctuation (effective value) of the voltage fluctuation component of the fluctuation frequency fn obtained as a result of frequency analysis of the voltage fluctuation, for example, as shown in FIG. 16, and an represents the flicker visibility shown in FIG. The flicker visibility coefficient corresponding to the fluctuation frequency fn when 10 Hz in the curve is set to 1 is shown. ΔV10 is a fluctuation value of 10 Hz in the flicker visibility curve. This ΔV10 is compared with a predetermined allowable value, and if it is equal to or smaller than the allowable value, it is determined that the power quality is good, and if it is equal to or larger than the allowable value, it is determined as defective.
Japanese Patent Laid-Open No. 9-322554 Japanese Patent Application No. 2006-2225016 specification and drawings

  Therefore, the problem to be solved by the present invention is to perform processing for suppressing or eliminating flicker by controlling the level of power fluctuation so that the power fluctuation does not become excessive to the extent that flicker problems occur while performing isolated operation detection at high speed. On the other hand, ΔV10 is satisfied when the flicker problem is solved.

  An isolated operation detection method according to the present invention is a method for detecting whether a distributed power source is disconnected from an electric power system and operating independently, by injecting electric power into the electric power system and detecting power fluctuations. And calculating a power amount (power fluctuation amount) to be injected to cause the power fluctuation in the power system based on a period deviation which is a deviation from the system cycle, and this step includes each fluctuation frequency fn of the power system. The voltage fluctuation amount ΔVn is converted into a fluctuation value ΔV10 of 10 Hz in the flicker visibility curve, and the above calculation is performed so that the converted fluctuation value ΔV10 satisfies an allowable value that is a criterion for countermeasures against flicker. To do.

  In the above, the injection of electric power for causing the electric power fluctuation may be arbitrary, such as periodic or irregular.

  The power fluctuation includes reactive power fluctuation, active power fluctuation, harmonic power fluctuation, and the like, and is not particularly limited.

  The deviation between the current system cycle and the past system cycle is not limited to a deviation obtained by moving and averaging a plurality of system cycles of the current and past system cycles. The past system cycle is a past system cycle by a predetermined cycle from the current system cycle.

  The allowable value is 0.23V (0.46V in 202V conversion) for new generator equipment, and 0.45V (0.9V in 202V conversion) when considering voltage flicker before interconnection.

  According to the present invention, when the single operation of the distributed power source is detected at high speed, when the power fluctuation is injected into the power system, the fluctuation value ΔV10 does not exceed the allowable value that is the criterion for countermeasures against flicker. The power fluctuation is suppressed to a value that does not cause flicker, so that there is no possibility of causing the flicker problem, and at the same time, the ΔV10 regulation can be satisfied.

  Preferably, when the fluctuation value ΔV10 does not satisfy an allowable value that is a criterion for countermeasures against flicker, the grid interconnection of the distributed power source is stopped.

  Preferably, the step includes a low-sensitive zone range in which the period deviation is a deviation range centered at 0 and the change rate of the power fluctuation amount with respect to the periodic deviation change is small, and the periodic deviation is outside the low-sensitive band range and the periodic deviation. While setting the high sensitivity range where the change rate of the power fluctuation amount with respect to the change is large, the range width of the low sensitivity range is widened so that the variation value ΔV10 satisfies the allowable value that is the criterion for countermeasures against flicker. Is to set. The absolute value of the period deviation in the low band is smaller than that in the high band. The low-sensitive range has a cyclic deviation centered at 0 and includes positive and negative cyclic deviations. While the range of change in the power fluctuation amount within this range is small, the sensitivity of islanding detection is set low. In the high-sensitive zone range, the variation range of the power fluctuation amount with respect to the period deviation can be increased, and the sensitivity of the isolated operation detection can be set high.

  In this case, more preferably, if the fluctuation value ΔV10 does not satisfy the allowable value that is a criterion for countermeasures against flicker even when the low range is set to the maximum, the grid interconnection of the distributed power source is stopped. It is.

  Preferably, the step includes a low-sensitive range where the change rate of the power fluctuation amount with respect to the periodic deviation is small in a deviation range in which the periodic deviation is centered at 0, and the periodic deviation is outside the low sensitive range. While setting a high sensitive zone range in which the change rate of the power fluctuation amount with respect to the periodic deviation change is large, the fluctuation value ΔV10 is used as a countermeasure against flicker. It is to set the size so as to satisfy the allowable value that is the criterion.

  In this case, more preferably, if the fluctuation value ΔV10 does not satisfy the allowable value that is the criterion for countermeasures against flicker even when the amount of power fluctuation within the low sensitivity range is minimized, the grid interconnection of the distributed power source is changed. Is to stop.

  Preferably, the step includes a low sensitivity range where the period deviation is a deviation range centered at 0 and a small change rate of the power fluctuation amount with respect to the period deviation change, and the period deviation is outside the low sensitivity range. While setting the high-sensitive range where the rate of change of the power fluctuation amount relative to the period deviation change is large, the fluctuation value ΔV10 is calculated from each of the U-phase system voltage and the W-phase system voltage, and the larger of both fluctuation values ΔV10 is selected. In addition, the range of the low sensitivity range is widened so that the selected fluctuation value ΔV10 satisfies the allowable value that is the criterion for countermeasures against flicker, or the change in the period deviation is injected within the low sensitivity range. Set the amount of power fluctuation to large or small.

  According to the present invention, isolated operation can be detected at high speed, while flicker can be suppressed by satisfying the ΔV10 rule.

  Hereinafter, an isolated operation detection method, its control device, an isolated operation detection device, and a distributed power supply system according to embodiments of the present invention will be described with reference to the accompanying drawings.

(Embodiment 1)
In the first embodiment, the system is the same as the distributed power supply system of FIG. Since the configuration of FIG. 11 has been described above, its description is omitted. The isolated operation detection device 18 is substantially the same as that in FIG. 12 except for the control device 24. In the first embodiment, the isolated operation detection device 18 is characterized by the configuration and operation of the control device 24 described with reference to FIGS. 1 to 5. FIG. 1 is a circuit diagram of the control device 24 of the first embodiment. In FIG. 1, parts corresponding to those in FIG. 12 are denoted by the same reference numerals, and description of the parts related to the same reference numerals is omitted because it has been described above.

  The islanding operation detection method of the first embodiment calculates the amount of power (power fluctuation amount) injected to cause power fluctuation in the power system based on the period deviation that is the deviation between the current system period and the past system period. Including the steps of: In this step, the voltage variation ΔVn at each variation frequency fn of the power system is converted into a variation value ΔV10 of 10 Hz in the flicker visibility curve, and the converted variation value ΔV10 satisfies an allowable value that is a criterion for countermeasures against flicker. Thus, the period deviation which is the deviation between the current system period and the past system period is calculated.

  The first embodiment is characterized in that the range width of the low-sensitive band range R1 is set to be wide so that the fluctuation value ΔV10 satisfies an allowable value that is a determination criterion for flicker countermeasures.

  Specifically, the first embodiment includes a low-sensitive band range width setting unit 50 that sets the range width of the low-sensitive band range R1 according to the calculation flow shown in FIG. 2, and a flicker abnormality determining unit 51.

  The low-sensitive band range width setting unit 50 includes a system voltage effective value measurement unit 50a (calculation flow step a), a flicker visual sensitivity curve equivalent filter 50b (calculation flow step b), and an effective value calculation unit 50c (calculation flow step). c) and a calculation unit 50d (step d of the calculation flow).

  The system voltage effective value measuring unit 50a performs frequency analysis on the fluctuation of the system voltage, and measures the voltage fluctuation ΔVn (the fluctuation of the effective value of the system voltage) at the fluctuation frequency fn of the power system.

  The flicker visual sensitivity curve equivalent filter 50b converts (filters) the voltage fluctuation ΔVn into a fluctuation value ΔV10 of 10 Hz using the flicker visual sensitivity curve shown in FIG.

  In FIG. 3, e1 represents a flicker visibility curve, and e2 represents a filter characteristic line of the filter 50b. This filter is a bandpass filter, and the filter characteristic line e2 of the filter 50b is slightly higher than the flicker visibility curve e1 of the grid connection regulation (JEAC 9701-2006) so that a margin is provided for voltage flicker. .

  The effective value calculation unit 50c calculates the effective value for several seconds of the converted fluctuation value ΔV10, in the embodiment, for 5 seconds.

  The computing unit 50d computes the range width of the low-sensitive range R1 according to FIG. 4 so that the effective fluctuation value ΔV10 does not exceed the allowable value that is the criterion for countermeasures against flicker.

  In FIG. 4, the horizontal axis represents the voltage deviation (ΔV10), and the vertical axis represents the range width of the low-sensitive range R1. The allowable value can be determined based on the grid connection regulations (JEAC 9701-2006). For example, 0.23V (0.46V in 202V conversion) for new generator equipment, and voltage flicker before connection is taken into consideration Is 0.45V (0.9V in terms of 202V).

  The effective value calculation unit 50c performs the effective value processing on the horizontal axis in FIG. 4 and outputs the effective value processing result to the calculation unit 50d. With respect to the horizontal axis in FIG. 4, the effective value calculation unit 50 c calculates the effective value calculation for 5 seconds as the voltage deviation (ΔV10) on the horizontal axis in FIG. 4.

  In the calculation unit 50d, even if the voltage deviation (ΔV10) increases or decreases between 0.4 and 0.45 in the hysteresis curve W1 indicated by the one-dot chain line in FIG. (± 0.01 means that the range width is 0.01 on the plus and minus sides with a period deviation of 0 as the center, and the range width is 0.02 as an absolute value), and the voltage deviation (ΔV10) is When increasing / decreasing between 0.45 and 0.9, the present low sensitive range R1 is changed to W1 by changing the range width of the low sensitive range R1 to ± 0.001 to ± 0.007. If it exceeds, W1 is clipped.

  Then, once the voltage deviation (ΔV10) becomes 0.9, when the voltage deviation (ΔV10) decreases, the range width of the low sensitivity range R1 is maintained at ± 0.07.

  When the voltage deviation (ΔV10) becomes 0.85, when the voltage deviation (ΔV10) increases or decreases, the range width of the low-sensitive band range R1 is increased or decreased by ± 0.07 to ± 0.01.

  That is, when the current low-sensitive band range R1 falls below the hysteresis curve W2 indicated by the dotted line, control is performed by a hysteresis operation in which the current low-sensitive range R1 is clipped to W2.

  In the above, since the output of the range width setting unit 50 is output as the range width setting signal of the low-sensitive band range R1 to the reactive energy calculation unit 40, the periodic deviation and reactive energy shown in FIGS. In accordance with the characteristic line L1 indicating the above relationship, the range width of the low-sensitive band range R1 can be set from ± 0.01 shown in FIG. 5A to ± 0.07 shown in FIG.

  In both FIG. 5A and FIG. 5B, the change width (inclination of the characteristic line L1) of the injection reactive power amount with respect to the period deviation change in the low sensitivity range R1 is the same.

  When calculating the injection reactive power amount based on the calculation result of the period deviation calculation unit 38, the reactive power amount calculation unit 40 calculates the injection reactive power amount with reference to the range width setting result of the range width setting unit 50. That is, when the reactive power is injected into the power system when the single operation of the distributed power source is detected at high speed, the reactive power injection is performed so that the fluctuation value ΔV10 does not exceed the allowable value that is the criterion for countermeasures against flicker. It is possible to satisfy the ΔV10 regulation by suppressing the amount below an amount that does not cause a flicker problem.

  Note that the calculation outputs of the effective value calculation unit 50 c and the calculation unit 50 d in the range width setting unit 50 are input to the flicker abnormality determination unit 51. In the flicker abnormality determination unit 51, the range width of the low sensitivity band range R1 is maximized from the calculation outputs of both the calculation units 50c and 50d, and the invalidity is injected per unit period deviation within the low sensitivity band range R1. If it is determined that the fluctuation value ΔV10 does not satisfy the allowable value that is the criterion for countermeasures against flicker even when the amount of electric power is minimized (flicker abnormality determination), the interconnection relays 20 and 22 are turned off to turn off the distributed power supply. Control to stop grid connection.

  In the first embodiment described above, the voltage flicker can be kept within the allowable value (ΔV10) by changing the range width of the low-sensitive range R1 by ΔV10, and the flickering of the fluorescent lamp does not occur. On the other hand, if the system voltage fluctuates, it is possible to break the complete balance between the generated power and the load power even if the range of the low sensitivity range R1 is widened. Never give. In addition, even when the range width of the low-sensitive range R1 is maximized, if the voltage flicker exceeds the allowable value (ΔV10), the grid interconnection of the distributed power supply is stopped.

(Embodiment 2)
In the second embodiment, the system is the same as the distributed power supply system of FIG. Since the configuration of FIG. 11 has been described above, its description is omitted. The isolated operation detection device 18 is substantially the same as that in FIG. 12 except for the control device 24. The second embodiment is characterized by the configuration and operation of the control device 24 described with reference to FIGS. FIG. 6 is a circuit diagram of the control device 24 of the second embodiment. 6, portions corresponding to those in FIG. 12 are denoted by the same reference numerals, and description of the portions related to the same reference numerals is omitted because it has been described above.

  The second embodiment is characterized in that it includes a reactive power amount (gain) setting unit 60 that calculates according to the calculation flow shown in FIG. 7 and a flicker abnormality determination unit 51.

  The gain setting unit 60 includes a system voltage effective value measurement unit 60a (step a1 in the calculation flow), a flicker visibility curve equivalent filter 60b (step b1 in the calculation flow), an effective value calculation unit 60c (step c1 in the calculation flow), And a calculation unit 60d (step d1 of the calculation flow).

  The system voltage effective value measuring unit 60a performs frequency analysis on the fluctuation of the system voltage and measures a voltage variation ΔVn (a fluctuation in the effective value of the system voltage) at the fluctuation frequency fn of the power system.

  The flicker visual sensitivity curve equivalent filter 60b converts (filters) the voltage fluctuation amount ΔVn into a fluctuation value ΔV10 of 10 Hz by the flicker visual sensitivity curve shown in the first embodiment.

  The effective value calculation unit 60c calculates the effective value for several seconds of the converted fluctuation value ΔV10, and for 5 seconds in the second embodiment.

  The calculation unit 60d calculates a reactive power amount (gain) according to FIG. 8 so that the effective fluctuation value ΔV10 does not exceed an allowable value that is a criterion for countermeasures against flicker. In FIG. 8, the horizontal axis represents voltage deviation (ΔV10), and the vertical axis represents reactive power (gain).

  The allowable value is the same as in the first embodiment.

  The effective value calculation unit 60c performs effective value processing on the horizontal axis of FIG. 8 and outputs the effective value processing result to the reactive power (gain) calculation unit 60d. With respect to the horizontal axis in FIG. 8, the effective value calculation unit 60c calculates the effective value calculation for 5 seconds as the voltage deviation (ΔV10) on the horizontal axis in FIG.

  In the calculation unit 60d, the reactive power (gain) is maintained at 300 even if the voltage deviation (ΔV10) increases or decreases between 0.4 and 0.45 in the hysteresis curve W1 indicated by the one-dot chain line in FIG. When the deviation (ΔV10) increases or decreases between 0.45 and 0.9, the current reactive power (gain) exceeds W1 by changing the reactive power (gain) from 0 to 300. And clip to W1. Then, once the voltage deviation (ΔV10) reaches 0.9, the reactive energy (gain) is maintained at 0 when the voltage deviation (ΔV10) decreases. When the voltage deviation (ΔV10) becomes 0.9, the reactive energy (gain) is maintained at 0 when the voltage deviation (ΔV10) increases or decreases from 0.85 to 0.9, and the voltage deviation (ΔV10) is At 0.85, the voltage deviation (ΔV10) is 0.4 to 0.85, and the reactive power (gain) is changed from 0 to 300.

  In the above description, the reactive power amount (gain) setting unit 60 output is output to the reactive power amount calculation unit 40 as a reactive power amount (gain) setting signal in the low-sensitive band range R1, so FIGS. ), The reactive power amount (gain) can be set from the reactive power amount (gain) shown in FIG. 9A to the reactive power amount (gain) shown in FIG. 9B. All gains satisfy the definition of ΔV10. Note that the range of the low-sensitive range R1 is maintained the same in both the case of FIG. 9A and FIG. 9B. 9 (a) and 9 (b) have the same range width, but the reactive power amount (gain) in the range width in FIG. 9 (a) is from cyclic deviation 0 to cyclic deviation. Although the absolute value increases as the absolute value increases, in FIG. 9B, the magnitude of the reactive power amount (gain) does not change even if the absolute value of the periodic deviation increases from zero. That is, in FIG. 9A and FIG. 9B, the slope of the characteristic line L1 changes. However, the gain change in FIGS. 9A and 9B is an example.

  The reactive power amount calculation unit 40 refers to the setting of the reactive power amount (gain) setting unit 60 and calculates the injection reactive power amount when calculating the injection reactive power amount based on the calculation result of the periodic deviation of the periodic deviation calculation unit 38. Calculate. That is, when reactive power is injected into the power system when single operation of the distributed power source is detected at high speed, the injection reactive power is set such that the fluctuation value ΔV10 does not exceed the allowable value that is the criterion for countermeasures against flicker. It is possible to satisfy the ΔV10 regulation by suppressing the amount below an amount that does not cause a flicker problem.

  The flicker abnormality determination unit 51 maximizes the range width of the low-sensitive band range R1 based on the calculation values of the effective value calculating unit 60c and the calculating unit 60d of the reactive power amount setting unit 60, and within the low-sensitive band range R1. If it is determined that the fluctuation value ΔV10 does not satisfy the allowable value, which is a criterion for flicker countermeasures, even if the amount of reactive power fluctuation injected per unit cycle deviation is minimized, the interconnection relay 20 , 22 is turned off and control is performed to stop the grid interconnection of the distributed power source.

  In the second embodiment described above, by changing the reactive power amount (gain) by ΔV10, the voltage flicker can be kept within the allowable value (ΔV10), and the flickering of the fluorescent lamp does not occur. On the other hand, if there is a fluctuation in the system voltage, it is possible to break the complete balance between the generated power and the load power even if the reactive power amount (gain) in the same range width is reduced. There is no impact on time. Further, even if the reactive power amount is set to a minimum, for example, 0, when the voltage flicker exceeds the allowable value (ΔV10), the grid interconnection of the distributed power supply is stopped.

(Embodiment 3)
FIG. 10 shows a block configuration of the control device 24 according to the third embodiment. The control device 24 shown in FIG. 10 includes a range width setting unit 50 and a reactive power (gain) setting unit 60 as the calculation unit 70, and the ΔV10 compatible range width setting unit 50 has a U phase. System voltage effective value measuring unit 50a, flicker visual sensitivity curve equivalent filter 50b, and effective value calculating unit 50c. ΔV10 corresponding reactive energy setting unit 60 is a W-phase system voltage effective value measuring unit 60a, flicker visual sensitivity curve. An equivalent filter 60b and an effective value calculator 60c are provided. The control device 24 includes a selection unit 70a, a calculation unit 70b, and a flicker abnormality determination unit 51.

  In the above configuration, the variation value ΔV10 is calculated from each of the U-phase system voltage and the W-phase system voltage by the range width setting unit 50 and the reactive energy (gain) setting unit 60, respectively, and the selection unit 70a calculates both the variation values ΔV10. The larger one is selected, and the range width of the low sensitivity range is widened so that the fluctuation value ΔV10 selected by the calculation unit 70b satisfies the allowable value that is a criterion for flicker countermeasures, or within the low sensitivity range. The amount of power fluctuation to be injected with respect to the period deviation change is set to a large or small value.

  Further, in the flicker abnormality determination unit 51, based on the outputs of the selection unit 70a and the calculation unit 70b, the range width of the low sensitive band range R1 is maximized and injected per unit period deviation within the low sensitive band range R1. Even if the reactive power fluctuation amount is minimized, if it is determined that the fluctuation value ΔV10 does not satisfy the allowable value, which is a criterion for countermeasures against flicker (flicker abnormality determination), the interconnection relays 20 and 22 are turned off and distributed. Control to stop the grid connection of the power supply.

(Embodiment 4)
FIG. 18 shows a block configuration of the control device 24 according to the fourth embodiment. The control device 24 shown in FIG. 18 includes a system voltage effective value measuring unit 80a, a flicker visibility curve equivalent filter 80b, and an effective value calculating unit 80c as the ΔV10 calculating unit 80, and an output of the ΔV10 calculating unit 80 is provided. And a flicker abnormality determination unit 51 to be input.

  In the above configuration, the flicker abnormality determination unit 51 determines that the fluctuation value ΔV10 calculated by the ΔV10 calculation unit 80 does not satisfy the allowable value that is the determination criterion for flicker countermeasures (flicker abnormality determination). 20 and 22 are turned OFF and control is performed to stop the grid interconnection of the distributed power source.

  As described above, in any of the embodiments, reactive power for causing power fluctuation from the control device 24 to the power system can be injected while satisfying ΔV10, and the isolated operation can be detected at high speed.

  As the fourth embodiment, the control device 24 may be configured to have a function of calculating the fluctuation value ΔV10 and to stop the grid interconnection when the fluctuation value ΔV10 exceeds an allowable value. .

FIG. 1 is a circuit diagram of a control device in the isolated operation detection device of Embodiment 1 of the present invention. FIG. 2 is a calculation flowchart of the low-sensitive band range calculation unit of the control device of FIG. FIG. 3 is a diagram for explaining a filter corresponding to the flickering visibility curve inside the control device of FIG. FIG. 4 is used for explaining the operation of the control device of FIG. 1 and is a diagram showing the relationship between the voltage deviation (ΔV10) and the low sensitivity range. FIG. 5A shows the relationship between the period deviation and the reactive energy, and the low sensitive range R1 is narrow, and FIG. 5B is the wide sensitive range R1. FIG. 6 is a circuit diagram of a control device in the isolated operation detection device according to the second embodiment of the present invention. FIG. 7 is a calculation flowchart of the low-sensitive range calculation unit of the control device of FIG. FIG. 8 is used to explain the operation of the control device of FIG. 6 and is a diagram showing the relationship between the voltage deviation (ΔV10) and the low sensitivity range. FIG. 9A shows the relationship between the periodic deviation and the reactive power amount, and shows a large change rate of the reactive power amount, and FIG. 9B shows a small change rate of the reactive power amount. FIG. 10 is a circuit diagram of a control device in the isolated operation detection device according to the third embodiment of the present invention. FIG. 11 is a diagram showing a configuration of a distributed power supply system including a distributed power supply and an isolated operation detection device to which the isolated operation detection method according to each embodiment of the present invention is applied. FIG. 12 is a circuit diagram of a control device in the isolated operation detection device of FIG. FIG. 13 is a diagram for explaining the calculation of the period deviation. FIG. 14 is a diagram illustrating the relationship between the period deviation and the reactive power amount. FIG. 15 is a diagram showing a configuration of another distributed power supply system including a distributed power supply and an isolated operation detection device to which the isolated operation detection method according to each embodiment of the present invention is applied. FIG. 16 is a diagram for explaining the flicker fluctuation voltage. FIG. 17 is a diagram for explaining the flicker visibility coefficient. FIG. 18 is a circuit diagram of a control device in the isolated operation detection device according to the fourth embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Distributed type power supply system 12 Distributed type power supply 14 Electric power system 16 Power conditioner 18 Independent operation detection apparatus

Claims (11)

In the method of detecting whether the distributed power source is disconnected from the power system and operating independently, by causing a power fluctuation in the power system,
Calculating a power amount (power fluctuation amount) to be injected to cause the power fluctuation in the power system based on a period deviation which is a deviation between a current system period and a past system period,
In this step, the voltage fluctuation ΔVn at each fluctuation frequency fn of the power system is converted into a fluctuation value ΔV10 of 10 Hz in the flicker visibility curve, and this converted fluctuation value ΔV10 satisfies an allowable value that is a criterion for countermeasures against flicker. The above-mentioned calculation is performed as described above.   2. The islanding operation detection method according to claim 1, wherein when the fluctuation value ΔV <b> 10 does not satisfy an allowable value that is a criterion for countermeasures against flicker, the grid interconnection of the distributed power source is stopped. The step includes a low-sensitive range where the periodic deviation is a deviation range centered at 0 and the rate of change of the power fluctuation amount relative to the periodic deviation is small, and the periodic deviation is outside the low-sensitive range and the periodic deviation While setting the high-sensitive range with a large change rate of the power fluctuation amount to the change,
2. The islanding operation detection method according to claim 1, wherein the range of the low-sensitive range is set so that the fluctuation value ΔV <b> 10 satisfies an allowable value that is a criterion for countermeasures against flicker.   If the fluctuation value ΔV10 does not satisfy the allowable value that is a criterion for flicker countermeasures even when the range of the low-sensitive range is set to the maximum, the grid interconnection of the distributed power supply is stopped. The isolated operation detection method according to claim 3. The step includes a low-sensitive range where the periodic deviation is a deviation range centered at 0 and the rate of change of the power fluctuation amount relative to the periodic deviation is small, and the periodic deviation is outside the low-sensitive range and the periodic deviation While setting the high-sensitive range with a large change rate of the power fluctuation amount to the change,
The amount of power fluctuation injected with respect to the period deviation change within the low sensitivity range is set to be large or small so that the fluctuation value ΔV10 satisfies an allowable value that is a criterion for countermeasures against flicker. The islanding operation detection method according to claim 1.   If the fluctuation value ΔV10 does not satisfy the allowable value, which is a criterion for countermeasures against flicker, even if the amount of power fluctuation injected per unit period deviation is minimized within the low sensitivity range, the grid connection of the distributed power source is set. The isolated operation detection method according to claim 5, wherein the operation is stopped. The step includes a low-sensitive range where the periodic deviation is a deviation range centered at 0 and the rate of change of the power fluctuation amount relative to the periodic deviation is small, and the periodic deviation is outside the low-sensitive range and the periodic deviation While setting the high-sensitive range with a large change rate of the power fluctuation amount to the change,
The fluctuation value ΔV10 is calculated from each of the U-phase system voltage and the W-phase system voltage, and the larger one of the two fluctuation values ΔV10 is selected so that the selected fluctuation value ΔV10 satisfies an allowable value that is a criterion for countermeasures against flicker. 2. The single operation according to claim 1, wherein the range width of the low sensitivity band range is set to be wide or narrow, or the amount of power fluctuation to be injected with respect to the period deviation change within the low sensitivity range is set to be large or small. Detection method.   In the control device that controls the detection operation for the isolated operation detection device that detects whether the distributed power source is disconnected from the power system and operated independently, the deviation between the current system cycle and the past system cycle (cycle A means for calculating a power fluctuation gain to be injected into the power system based on the deviation), and this means converts a voltage fluctuation amount ΔVn at each fluctuation frequency fn of the power system to a fluctuation value ΔV10 of 10 Hz in the flicker sensitivity curve. In addition, the control device performs the calculation so that the converted fluctuation value ΔV10 satisfies an allowable value that is a criterion for countermeasures against flicker.   9. The control apparatus according to claim 8, wherein the means is constituted by a microcomputer provided with a software program.   An isolated operation detection device for detecting whether or not a distributed power source is isolated from an electric power system and operated independently, comprising the control device according to claim 8 or 9, comprising an isolated operation detection device.   The distributed operation system comprising: a distributed power supply; and an isolated operation detection device that detects whether or not the distributed power supply is isolated from the power system and operates independently. A distributed power supply system characterized by being a single operation detection device.

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