JP2007074846A - Method of controlling voltage of distribution system, device and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a difference of facility utilization factors between distributed power supplies in a distribution system and a difference between power selling incomes, and to suppress the deterioration of the energy utilization efficiency of the power supply in the distribution system as whole. <P>SOLUTION: This voltage control method calculates voltage sensitivity with respect to the change amount of active power from the change amount of active power at a tie point between a distribution line and the distributed power supply B and the change amount of a voltage, and when the voltage sensitivity is not higher than a threshold for determining whether aid by an output of inactive power should be performed or not, the voltage control method determines that the other distributed power supply A is shifted to voltage-rise suppression control, and makes the distributed power supply B start the aid by the output of the inactive power. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a voltage control method, apparatus, and program for a distribution system. More specifically, the present invention relates to a voltage control method, apparatus, and program for a distribution system in which a plurality of distributed power sources are interconnected.

  In Japan, interconnection of distributed power sources to commercial power systems is underway. Along with this, there is a concern about a voltage increase due to reverse power flow from the distributed power source when a large amount of the distributed power source is introduced into the distribution system. In some cases, it may exceed 107 [V], which is the upper limit of the appropriate range defined by the Electricity Business Law.

  When a distributed power source is connected to the grid, measures are taken in accordance with the distributed power system connection technical guidelines (Non-Patent Document 1).

  The countermeasure to suppress the voltage increase of the conventional distribution system based on the distributed power system interconnection technical guidelines is to first control the phase advance reactive power, and if this does not provide a sufficient suppression effect, the output active power is reduced. It is something to be made.

NEC Association: Distributed Power System Integration Technical Guidelines (JEAG 9701-2001), 2001.

  However, when a plurality of distributed power sources are introduced into the same distribution system, the voltage at some points may easily increase due to the influence of the line impedance of the distribution system. In such a case, according to the countermeasures based on the distributed power system interconnection technical guidelines, depending on the conditions, only the distributed power supplies at some points will suppress the voltage rise, and the output of some of these distributed power supplies is effective. This leads to a reduction in power.

  For this reason, non-uniformity of output active power is caused between distributed power sources in the distribution system, and there is a disparity in equipment utilization rates at the locations where distributed power sources are installed, and income disparities when surplus power is sold. There is a problem of inviting. Furthermore, as a result, there is a problem that the energy utilization efficiency of the entire power supply in the distribution system is reduced.

  Therefore, the present invention provides a distribution system that can suppress the facility utilization rate between the distributed power sources in the power distribution system and the difference in power sales revenue, and can suppress a decrease in energy use efficiency as the entire power source in the power distribution system. It is an object to provide a voltage control method, apparatus, and program.

  In order to achieve this object, a voltage control method for a distribution system according to claim 1 is a connection point between a distribution line and a distributed power source B in a distribution system in which a plurality of distributed power sources are linked to the distribution line. The voltage sensitivity for the active power change is calculated from the change in the active power and the change in the voltage, and the voltage sensitivity for the active power change is less than the threshold for determining whether or not subsidy by reactive power output is performed. In this case, it is determined that the other distributed power source A has shifted to the voltage rise suppression control, and the distributed power source B starts subsidy with reactive power output.

  Further, the voltage control device for the distribution system according to claim 5 is a means for calculating the voltage sensitivity for the change in the effective power from the change in the active power and the change in the voltage at the connection point between the distribution line and the distributed power source. And a means for outputting a control command with a content that causes the distributed power source to start subsidy by reactive power output when the voltage sensitivity to the active power change is equal to or less than a threshold for determining whether or not subsidy by reactive power output is performed And a control device including

  Furthermore, the voltage control program for the distribution system according to claim 9, wherein the computer controls at least the amount of change in active power from the amount of change in active power and the amount of change in voltage at the connection point between the distribution line and the distributed power source. Means for calculating voltage sensitivity, control of content that causes distributed power source to start subsidy by reactive power output when voltage sensitivity to active power change is below threshold for determining whether to subsidize by reactive power output It is made to function as a means for outputting a command.

  Here, in a distribution system in which a plurality of distributed power sources are interconnected, the distributed power source in which the voltage of the distribution system has reached the upper limit of the appropriate range shifts from normal operation with a constant power factor to voltage rise suppression control. Is roughly equivalent to switching the distributed power source from a constant power source to a constant voltage source, and the system impedance of other distributed power sources connected to the same distribution line is reduced. In the distributed power source that is changing, the voltage sensitivity to the change in active power (the voltage change divided by the change in active power) decreases. Therefore, according to the voltage control method, apparatus and program of this distribution system, when the voltage sensitivity to the active power change at the connection point between the distribution line and the distributed power source B decreases, the distribution line is connected to the same distribution line. It is determined that the other distributed power source A has shifted to the voltage rise suppression control, and the subsidy by the reactive power output from the distributed power source B is started. In addition, by monitoring the active power and voltage at the connection point between the distribution lines and the distributed power supply, the distributed power supply connected to the distribution system functions autonomously to control the voltage of the entire distribution system. Do.

  According to a second aspect of the present invention, in the voltage control method for the distribution system according to the first aspect, the subsidy by the reactive power output at the maximum output that the distributed power source B can output is started.

  According to a sixth aspect of the present invention, in the voltage control device for the distribution system according to the fifth aspect, the means for outputting a control command for starting the subsidy by the reactive power output is a maximum output that can be output to the distributed power source. A control command for starting subsidy by reactive power output is output.

  A tenth aspect of the present invention is the distribution system voltage control program according to the ninth aspect, wherein the computer outputs a control command having a content for starting subsidy by reactive power output at a maximum output that can be output to the distributed power source. It is made to function as a means.

  In this case, the subsidy by the reactive power output at the maximum output that can be output by the distributed power source is started, and exceeding the appropriate range of the voltage of the distribution system can be quickly resolved from the beginning of the subsidy.

  According to a third aspect of the present invention, in the voltage control method for a power distribution system according to the first or second aspect, after the distributed power source B starts subsidy by reactive power output, the distribution line and the distributed power source B are connected. The voltage sensitivity for the reactive power change is calculated from the reactive power change and the voltage change at the system point, and whether or not the voltage sensitivity for the reactive power change stops the reduction of the reactive power output for the subsidy. When it is larger than the threshold for determination, the distributed power source B gradually reduces the reactive power output for the subsidy, and the voltage sensitivity with respect to the reactive power change amount stops the reduction of the reactive power output for the subsidy. If it is below the threshold value for determining whether or not the distributed power source A has shifted to constant voltage control, the distributed power source B stops the reduction of the reactive power output for subsidy. .

  According to a seventh aspect of the present invention, in the voltage control device for a distribution system according to the fifth or sixth aspect, the control device senses a voltage sensitivity with respect to a reactive power variation from a reactive power variation and a voltage variation at the interconnection point. If the voltage sensitivity to the reactive power change is greater than the threshold value for determining whether to stop the reduction of reactive power output for subsidy, the distributed power source is disabled for subsidy A means for outputting a control command with a content that lowers the power output step by step, and a voltage sensitivity with respect to the reactive power change is below a threshold for determining whether or not to stop the reduction of the reactive power output for the subsidy Includes a means for outputting a control command with a content to stop the decrease in reactive power output for subsidizing the distributed power source.

  According to the eleventh aspect of the present invention, in the voltage control program for the distribution system according to the ninth or tenth aspect, the computer is provided with a voltage sensitivity to the reactive power variation from the reactive power variation and the voltage variation at the interconnection point. Means for calculating, reactive power output for subsidy to distributed power source if voltage sensitivity to reactive power change is greater than threshold for determining whether to stop reduction of reactive power output for subsidy A means for outputting a control command with a content that lowers the power step by step, and if the voltage sensitivity with respect to the reactive power change is equal to or less than a threshold value for determining whether to stop the reduction of the reactive power output for subsidy The type power supply is made to function as a means for outputting a control command with a content for stopping the decrease in reactive power output for subsidy.

  Here, when a distributed power source shifts from voltage rise suppression control to voltage constant control, voltage control is performed not only in the voltage rise direction but also in the voltage drop direction, and the same when the voltage rises as well as when the voltage rises. The system impedance viewed from other distributed power sources connected to the distribution line will decrease. Therefore, in the case of the voltage control method, apparatus, and program for this distribution system, the voltage sensitivity (the change in voltage is the change in reactive power) with respect to the change in reactive power at the connection point between the distribution line and the distributed power source B. The distributed power source B reduces the reactive power output for subsidy and the reactive power output is adjusted until it is determined that the other distributed power source A has shifted to constant voltage control.

  Furthermore, the invention according to claim 4 is the voltage control method for the distribution system according to any one of claims 1 to 3, after the distributed power source B starts subsidy by reactive power output, or the distributed power source After B stops the reduction of the reactive power output for subsidy, the voltage sensitivity for the reactive power fluctuation is calculated from the reactive power fluctuation and the voltage change at the interconnection point, and the voltage sensitivity for the reactive power fluctuation is calculated. Is larger than a threshold value for determining whether or not to stop the reactive power output for subsidy, it is determined that the distributed power source A has released the voltage increase suppression control or the voltage constant control that has been shifted after the voltage increase suppression control Thus, the distributed power source B stops the reactive power output for the subsidy.

  According to an eighth aspect of the present invention, in the voltage control device for a distribution system according to any one of the fifth to seventh aspects, the control device is ineffective based on a reactive power variation and a voltage variation at the interconnection point. A means for calculating the voltage sensitivity for the power fluctuation, and a subsidy for the distributed power source when the voltage sensitivity for the reactive power fluctuation is greater than a threshold value for determining whether to stop the reactive power output for the subsidy. And a means for outputting a control command for stopping the reactive power output.

  According to a twelfth aspect of the present invention, in the voltage control program for a power distribution system according to any one of the ninth to eleventh aspects, the computer is configured to change the reactive power from the variation of the reactive power and the voltage variation at the interconnection point. Means for calculating voltage sensitivity for fluctuations, for subsidizing distributed power sources when voltage sensitivity for reactive power fluctuations is greater than a threshold for determining whether to stop reactive power output for subsidies It is made to function as a means for outputting a control command with the content of stopping the reactive power output.

  Here, releasing a constant voltage control from a certain distributed power source is equivalent to switching the distributed power source to a constant power source again, as seen from other distributed power sources connected to the same distribution line. The system impedance will be restored. Therefore, in the case of the voltage control method, apparatus, and program for this distribution system, when the voltage sensitivity to the reactive power fluctuation at the connection point between the distribution line and the distributed power source B increases, the distribution line is connected to the same distribution line. It is determined that the other distributed power source A in the system has released the constant voltage control, and the reactive power output for subsidy by the distributed power source B is stopped.

  As described above, according to the voltage control method, apparatus, and program of the distribution system according to claims 1, 5, and 9, since the output decrease of the active power of the distributed power source that performs the voltage increase suppression control is suppressed, It is possible to suppress the non-uniformity of the output active power that occurs between distributed power sources in the distribution system, and to suppress the disparity in equipment utilization rates at the locations where distributed power sources are installed and the income disparity when surplus power is sold. It is possible.

  In addition, according to the voltage control method, apparatus, and program of the distribution system according to claims 2, 6, and 10, the excess of the appropriate range of the distribution system voltage is quickly resolved from the start of the subsidy by supplying the maximum output reactive power. Therefore, it is possible to quickly control the voltage of the distribution system.

  In addition, according to the voltage control method, apparatus, and program of the distribution system according to claims 3, 7 and 11, the distributed power supply reduces the reactive power output for subsidy and adjusts the reactive power output. By optimizing the reactive power output required for voltage control of the grid, the burden of reactive power output for subsidy by the distributed power source can be minimized, and the energy utilization efficiency of the entire power source in the distribution system can be reduced. It becomes possible to more appropriately utilize the power supply capability of the distribution system by controlling the decrease more appropriately.

  Furthermore, according to the voltage control method, apparatus, and program for the distribution system according to claims 4, 8, and 12, the reactive power output for subsidization by the distributed power source is stopped under certain conditions. The operation of the subsidy by the reactive power output required for the voltage control of the power supply can be optimized, and unnecessary subsidy by the distributed power source can be avoided.

  Furthermore, according to the present invention, the distributed power source linked to the power distribution system can function autonomously and perform voltage control of the entire power distribution system. This mechanism can be constructed easily.

  Hereinafter, the configuration of the present invention will be described in detail based on the best mode shown in the drawings.

  1 and 2 show an example of an embodiment of a voltage control method and apparatus for a distribution system according to the present invention. In this embodiment, as shown in FIG. 2, as a distribution system in which a plurality of distributed power sources are connected, a distributed power source A and a distribution line 3 connected to a substation 2 and having a line impedance 4 are connected. The power distribution system 1 in which B is connected at the connection points 5a and 5b is taken as an example.

  The voltage control device of the present invention includes a first voltage sensitivity calculation unit, a first voltage sensitivity comparison unit, a second voltage sensitivity calculation unit, a second voltage sensitivity comparison unit, and a third voltage sensitivity comparison. And a control command output means. The first voltage sensitivity calculation means calculates the voltage sensitivity for the active power change from the change in active power and the change in voltage at the connection point between the distribution line and the distributed power source. The first voltage sensitivity comparison means compares the voltage sensitivity with respect to the amount of change in active power at the connection point between the distribution line and the distributed power source and a threshold value for determining whether or not subsidy by reactive power output is performed. It is determined whether or not the distributed power source should start subsidy with reactive power output.

  Further, the second voltage sensitivity calculation means calculates the voltage sensitivity for the reactive power change from the change of the reactive power and the voltage change at the connection point between the distribution line and the distributed power source. The second voltage sensitivity comparison means is a threshold for determining whether or not to stop the decrease in reactive power output for voltage sensitivity and subsidy for the reactive power change at the interconnection point between the distribution line and the distributed power source. And the distributed power source determines whether or not the reactive power output for subsidy should be reduced step by step.

  Still further, the third voltage sensitivity comparison means calculates the voltage sensitivity for the reactive power fluctuation from the reactive power fluctuation and the voltage change at the connection point between the distribution line and the distributed power source and this voltage. The sensitivity and the threshold value for determining whether to stop the reactive power output for the subsidy are compared to determine whether the distributed power source should stop the reactive power output for the subsidy. Then, the control command output means outputs a control command to the distributed power source based on the determination result of the first voltage sensitivity comparison means or the like.

  Here, the present invention autonomously controls each of the distributed power sources connected to the power distribution system to control the voltage of the power distribution system. In this embodiment, the distributed power source A is Both the case where the subsidy by the reactive power output is performed and the case where the subsidy is received are conceivable, and the distributed power source B can be both subsidized by the reactive power output and the subsidy. In the present embodiment, an example will be described in which the distributed power source A is subsidized by reactive power output and the distributed power source B is subsidized by reactive power output.

  The relationship between the distributed power sources A and B and the flow of each operation under the above assumption will be described with reference to FIG. The distributed power source A performs a normal operation with a constant power factor (F1). The distributed power source B starts or changes the output of active power and monitors the voltage sensitivity for the change in active power (F2). Specifically, the first voltage sensitivity calculation means of the voltage control device determines the voltage corresponding to the change in active power from the change in active power and the change in voltage at the interconnection point 5b between the distribution line 3 and the distributed power source B. Calculate the sensitivity. When the voltage at the interconnection point 5a between the distributed power source A and the distribution line 3 rises and the voltage at the interconnection point 5a reaches the upper limit of the standard value of the distribution system 1 (F3), the distributed power source A becomes invalid. Voltage rise suppression control by power output is started (F4). At this time, the distributed power source B connected to the same distribution line 3 is detected with a decrease in voltage sensitivity to the amount of change in active power at the connection point 5b. When the decrease in the voltage sensitivity falls below a predetermined threshold (F5), the distributed power source B determines that the distributed power source A has shifted to the voltage increase suppression control and generates a reactive power output for further assistance by itself. Start (F6). Specifically, the first voltage sensitivity comparison unit compares the voltage sensitivity with respect to the amount of change in the active power at the interconnection point 5b and a threshold value for determining whether or not the subsidy by the reactive power output is performed. When the voltage sensitivity falls below the threshold value (F5), the control command output means starts to output reactive power for subsidy to the distributed power source B based on the determination result of the first voltage sensitivity comparison means. A control command with the content to be output is output (F6). At this time, it is preferable to output the reactive power for subsidization at the maximum output.

  Further, the distributed power source B starts monitoring the voltage sensitivity with respect to its reactive power change (F7). Specifically, the second voltage sensitivity calculating means of the voltage control device determines the voltage corresponding to the reactive power change from the reactive power change and the voltage change at the interconnection point 5b between the distribution line 3 and the distributed power source B. Calculate the sensitivity. Subsequently, the distributed power source B starts to gradually reduce the reactive power output for subsidization (F8). When the reactive power output of the distributed power source A increases as the reactive power output of the distributed power source B decreases and reaches the reactive power output upper limit (F9), the distributed power source A starts constant voltage control. (F10). At this time, when the voltage sensitivity with respect to the reactive power change at the interconnection point 5b is reduced to be equal to or lower than a predetermined threshold value (F11), the distributed power source B stops the gradual decrease in the reactive power output for subsidy. (F12). Specifically, the second voltage sensitivity comparison unit compares the voltage sensitivity with respect to the reactive power change at the interconnection point 5b and a threshold value for determining whether or not to stop the reduction of the reactive power output for subsidy. To do. When the voltage sensitivity falls below the threshold value (F11), the control command output means outputs a reactive power output for subsidizing the distributed power source B based on the determination result of the second voltage sensitivity comparison means. A control command with the content of stopping the target drop is output (F12).

  Subsequently, when the voltage of the distribution system 1 decreases and the voltage at the connection point 5a falls below the upper limit of the standard value of the distribution system 1 (F13), the distributed power source A cancels the constant voltage control (F14). At this time, when the voltage sensitivity to the reactive power change at the interconnection point 5b increases and becomes greater than a predetermined threshold value (F15), the distributed power source B stops the reactive power output for subsidy (F16). . Specifically, the third voltage sensitivity comparison means of the voltage control device determines the voltage for the reactive power fluctuation from the reactive power fluctuation and the voltage fluctuation at the interconnection point 5b between the distribution line 3 and the distributed power source B. The sensitivity is calculated and the voltage sensitivity is compared with a threshold value for determining whether or not to stop the reactive power output for the subsidy. Then, when the voltage sensitivity becomes larger than the threshold value (F15), the control command output means stops the reactive power output for subsidizing the distributed power source B based on the determination result of the third voltage sensitivity comparison means. The control command with the content to be output is output (F16).

  More specifically, as shown in the flow diagram of FIG. 1, the voltage control method for the distribution system according to the present invention starts with the subsidy by the reactive power output. The step (S1) of detecting the voltage vsa and the current Isa in the normal operation state at the interconnection point 5a between the electric wire 3 and the distributed power source A by the voltage / current detection device 6, and the voltage vsa is the upper limit of the standard value of the distribution system 1 (S2; Yes), the distributed power source A includes a step (S1-3) of starting voltage rise suppression control by reactive power output. As for the control of the distributed power source B, a step (S1) of detecting the voltage vsb and the current Isb in the normal operation state at the connection point 5b between the distribution line 3 and the distributed power source B by the voltage / current detection device 6; When the voltage vsb does not exceed the upper limit of the standard value of the distribution system 1 (S2; No), the step of calculating the active power Ps in the normal operation state based on the voltage vsb and the current Isb (S2-3), When the output of the active power of the distributed power source B is changed (S2-4), the voltage vc and current Ic at the connection point 5b are detected by the voltage / current detection device 6 and effective based on the voltage vc and current Ic. A step (S2-5) of calculating the active power Pc in a state where the output of the power is changed, a change Δv1 in the voltage is calculated from the voltage vsb and the voltage vc, and effective from the active power Ps and the active power Pc. Change in power A step (S2-6) for calculating the minute ΔP, a step (S2-7) for calculating the voltage sensitivity Sp with respect to the active power change amount from the voltage change Δv1 and the active power change ΔP, and the voltage sensitivity Sp. The step of comparing with the threshold value Sps for determining whether or not the subsidy by the reactive power output is performed (S2-8) and when the voltage sensitivity Sp is larger than the threshold value Sps (S2-8; No) If the power source B is not subsidized by reactive power output and continues normal operation (S2-9), and the voltage sensitivity Sp is less than or equal to the threshold Sps (S2-8; Yes), the distributed power source B is reactive power And a step (S2-10) of starting subsidy by output.

  Further, as a step of adjusting the reactive power subsidy amount, for the control of the distributed power source A, after the distributed power source A starts the voltage increase suppression control by the reactive power output (S1-4), the distributed power source B is disabled. When the reactive power output of the distributed power source A increases as the power output gradually decreases (S2-12) and reaches the upper limit value of the reactive power output (S1-5; Yes), the distributed power source A becomes a voltage. Step (S1-6) for shifting to constant voltage control that also suppresses voltage drop in addition to rising suppression, and when the reactive power output falls below the reactive power output threshold after the distributed power source A shifts to constant voltage control ( S1-7; Yes) has a step (S1-8) in which the distributed power source cancels the constant voltage control. As for the control of the distributed power source B, the voltage / current detection device 6 detects the voltage vm and the current Im at the interconnection point 5b after the distributed power source B starts subsidy by reactive power output (S2-10). Then, the reactive power Qm is calculated in a state where the reactive power output is started based on the voltage vm and the current Im (S2-11), and the reactive power output for subsidization by the distributed power source B is gradually reduced. Step (S2-12) and the voltage vi and current Ii at the interconnection point 5b in a state where the reactive power output is stepped down for the i-th (i = 1, 2, 3,...) A step (S2-13) of calculating the reactive power Qi in a state where the reactive power output for subsidy is reduced based on the voltage vi and the current Ii detected by the current detection device 6, and the voltage vi Calculate change Δv2i And calculating the reactive power change ΔQi for the reactive power Qi (S2-14) and calculating the voltage sensitivity Sqi for the reactive power change from the voltage change Δv2i and the reactive power change ΔQi ( S2-15), a step (S2-16) for comparing the voltage sensitivity Sqi with a threshold value Sqs for determining whether or not to stop the reduction of the reactive power output for the subsidy, and the voltage sensitivity Sqi is a threshold value When it is larger than Sqs, the step (S2-16; No) of returning to the step (S2-12) in which the reactive power output for the subsidization by the distributed power source B is reduced stepwise, and the voltage sensitivity Sqi is less than or equal to the threshold value Sqs. In the case of (S2-16; Yes), the step (S2-17) in which the distributed power source B stops the reduction of the reactive power output for the subsidy, and the reduction of the reactive power output for the subsidy of the distributed power source B Stop (S2-17) When the voltage sensitivity Sqf with respect to the reactive power fluctuation is greater than the threshold value Sqs ′ for determining whether or not to stop the reactive power output for the subsidy (S2-18; Yes) The distributed power source B has a step (S2-19) of stopping the reactive power output for the subsidy.

  First, as an initial state of application of the voltage control method of the present invention, distributed power sources A and B connected to the distribution system 1 perform normal operation with a constant power factor and supply power to the distribution system 1 (S0). ).

  For the control of the distributed power source A, the voltage / current detection device 6 detects the voltage vsa and the current Isa in the normal operation state at the connection point 5a between the distribution line 3 and the distributed power source A. For the control, the voltage vs current detector 6 detects the voltage vsb and current Isb in the normal operation state at the connection point 5b between the distribution line 3 and the distributed power source B (S1).

  The voltage vsa and current Isa, and the voltage vsb and current Isb are detected using a voltage / current detector 6 at predetermined time intervals. For example, an interval of 1 second is conceivable as the detection time interval, but is not limited to this, and may be a time interval shorter than this or a time interval longer than this.

  Next, the voltages vsa and vsb detected in S1 are compared with the upper limit of the standard value of the distribution system 1 (S2). In addition, the upper limit of the standard value of the power distribution system 1 is 107 [V] at present.

  In the present embodiment, a case will be described in which the voltage vsa exceeds the upper limit of the standard value of the distribution system 1 and the voltage vsb does not exceed the upper limit of the standard value of the distribution system 1 in accordance with the above premise.

  Since the voltage vsa exceeds the upper limit of the standard value of the distribution system 1 (S2; Yes), the control of the distributed power source A starts the voltage increase suppression control at the interconnection point 5a by the reactive power output (S1- 3).

  On the other hand, since the voltage vsb does not exceed the upper limit of the standard value of the distribution system 1 (S2; No), the control of the distributed power source B is effective in the normal operation state based on the voltage vsb and the current Isb detected in S1. The power Ps is calculated (S2-3).

  The active power Ps can be calculated by, for example, (Formula 1) with the phase difference between the voltage vsb and the current Isb as θs, but the method of calculating the active power Ps is not limited to this and is another method. It doesn't matter.

  Ps = vsb · Isb · cos (θs) (Formula 1)

  Here, Ps: active power [W], vsb: voltage [V], Isb: current [A], θs: phase difference [deg] between voltage vsb and current Isb.

  Next, the output of the active power of the distributed power source B is changed (S2-4).

  The change in the output of the active power of the distributed power source B is, for example, to increase the output at the start of the distributed power source B, increase the output to make better use of the power supply capability, or to perform voltage control of the present invention. Any reason may be used, such as a periodic change in the intentional output.

  The active power Pc in a state where the voltage vc and the current Ic at the interconnection point 5b are detected in accordance with the change in the active power output of the distributed power source B and the output of the active power is changed based on the voltage vc and the current Ic. Is calculated (S2-5). Note that the active power Pc is calculated by (Equation 1) or the like.

  Then, the voltage change Δv1 is calculated from the voltage vsb detected in S1 and the voltage vc detected in S2-5 by (Equation 2), and the active power Ps calculated in S2-3 and S2-5 are calculated. A change ΔP of the active power is calculated from the active power Pc by (Equation 3) (S2-6).

  Δv1 = vc−vsb (Formula 2)

  Here, Δv1: change in voltage, vc: voltage in a state where the output of active power is changed, vsb: voltage in a normal operation state. All units are [V].

  ΔP = Pc−Ps (Formula 3)

  Here, ΔP: active power change amount, Pc: active power in a state where the output of active power is changed, and Ps: active power in a normal operation state. All units are [W].

  Further, the voltage sensitivity Sp for the active power change is calculated from (Equation 4) from the voltage change Δv1 and the active power change ΔP calculated in S2-6 (S2-7).

  Sp = Δv1 / ΔP (Formula 4)

  Here, Sp: voltage sensitivity [V / W] with respect to the change in active power, Δv1: change in voltage [V], ΔP: change in active power [W].

  Next, a comparison is made between the voltage sensitivity Sp calculated in S2-7 and a threshold value Sps for determining whether or not subsidy by reactive power output is performed (S2-8).

  The magnitude of the threshold value Sps is set to an appropriate value by the operator in consideration of, for example, the voltage vsb and active power Ps in the normal operation state and the magnitude of the voltage change Δv1. For example, it is conceivable to set the threshold value Sps in the range of about 0.05 to 0.1, but the value of the threshold value Sps is not limited to this, and may be a value larger or smaller than this.

  When the voltage sensitivity Sp is greater than the threshold value Sps (Sp> Sps) (S2-8; No), the distributed power source B continues normal operation without subsidy by reactive power output (S2-9). .

  On the other hand, when the voltage sensitivity Sp is equal to or less than the threshold value Sps (Sp ≦ Sps) (S2-8; Yes), the distributed power source B starts subsidy with reactive power output (S2-10).

  As described above, the distributed power source A is determined that the voltage of the power distribution system reaches the upper limit of the appropriate range as the voltage of the power distribution system rises, and the distributed power source A shifts from the normal operation with a constant power factor to the voltage rise suppression control. This is roughly equivalent to switching from a power source to a constant voltage source, and the system impedance viewed from the distributed power source B connected to the same distribution line 3 is reduced. In particular, in the distributed power source B in which the output of active power is changing, This is based on the idea that the voltage sensitivity Sp with respect to the amount of change in active power decreases. In other words, when the voltage sensitivity Sp with respect to the change in active power decreases, it is determined that the distributed power source A connected to the same distribution line has shifted to the voltage increase suppression control, and the distributed power source B is invalid. The subsidy by electric power output is started.

  The reactive power output for subsidization by the distributed power source B may be automatically stopped after a lapse of a certain time from the start of the output, or the operating state of the distributed power source A as in this embodiment described later. May be determined and stopped based on the operating state. Here, for example, about one hour is conceivable as the fixed time for automatically stopping the reactive power output, but it is not limited to this, and it may be shorter or longer. When the reactive power output is automatically stopped after a certain period of time, the control of the distributed power source B returns to the state of S0 and performs the processing after S1 again. If necessary, the reactive power output is output again. Start subsidy by

  Here, when the distributed power source B starts subsidy by reactive power output, it is preferable to start subsidy with the maximum output reactive power that the distributed power source B can output, that is, the maximum subsidy amount. In the case where the subsidy at the maximum output that can be output by the distributed power source B is not started, for example, the subsidy may be started at an output of about 80% of the maximum output.

  Subsequently, the voltage vm and the current Im at the interconnection point 5b are detected by the voltage / current detection device 6, and the reactive power Qm in a state where the reactive power output is started is calculated based on the voltage vm and the current Im (S2- 11).

  The reactive power Qm can be calculated by, for example, (Formula 5) where the phase difference between the voltage vm and the current Im is θm, but the method of calculating the reactive power Qm is not limited to this, and is another method. It doesn't matter.

  Qm = vm · Im · sin (θm) (Formula 5)

  Here, Qm: reactive power [Var], vm: voltage [V], Im: current [A], θm: phase difference [deg] between voltage vm and current Im.

  Next, the reactive power output for subsidization by the distributed power source B is reduced stepwise (S2-12).

  There is no particular limitation on the amount of reduction per one time when the reactive power output for subsidy is reduced stepwise, for example, it may be possible to reduce the reactive power one by one at the time of starting subsidy, etc. . However, the width of the decrease per time is not limited to this, and may be a width larger than this or a width smaller than this. In addition, the width | variety of each fall at the time of reducing in steps may be the same width | variety, or a different width | variety. For example, in the initial stage of the gradual decrease, the range of the decrease may be made relatively large and gradually decreased.

In accordance with the gradual decrease in reactive power output for subsidization by the distributed power source B, the voltage v _{i at} the interconnection point 5b in the ith (i = 1, 2, 3,...) Gradual decrease. And the current I _i are detected by the voltage / current detector 6, and the reactive power Q _{i in} a state in which the reactive power output for subsidy is reduced is calculated based on the voltage v _i and the current I _i (S2-13). ). The reactive power Q _i is calculated by (Equation 5) or the like.

Then, as represented by the voltage _{v i} detected by S2-13 and calculates the variation .DELTA.v2 _i of the voltage represented by (Equation 6), the reactive power _{Q i} calculated in S2-13 (Equation 7) Reactive power change ΔQ _i is calculated (S2-14).

Δv2 _i = v _i −v _i−1 (Expression 6)

Where Δv2: voltage change [V], v: voltage [V], subscript i: number of stepwise reductions in reactive power output (i = 1, 2, 3,...). Note that, in the first stepwise decrease (i = 1), v _i−1 becomes v ₀ , but v ₀ is equal to vm measured in S2-11.

ΔQ _i = Q _i −Q _i−1 (Expression 7)

Where ΔQ: reactive power change [Var], Q: reactive power [Var], subscript i: number of stepwise reductions in reactive power output (i = 1, 2, 3,...). In the first stepwise decrease (i = 1), Q _i−1 becomes Q ₀ , but Q ₀ is equal to Qm calculated in S2-11.

Further, the voltage sensitivity Sq _i for the reactive power change is calculated from the voltage change Δv2 _i and the reactive power change ΔQ _i calculated in S2-14 by (Equation 8) (S2-15).

Sq _i = Δv2 _i / ΔQ _i (Expression 8)

  Here, Sq: voltage sensitivity [V / Var] with respect to reactive power variation, Δv2: voltage variation [V], ΔQ: reactive power variation [Var], subscript i: stepwise decrease in reactive power output Number of times (i = 1, 2, 3,...).

Next, a comparison is made between the voltage sensitivity Sq _i calculated in S2-15 and a threshold value Sqs for determining whether or not to stop the reduction of reactive power output for subsidy (S2-16).

The threshold Sqs is set to an appropriate value by the operator in consideration of, for example, the voltage vm and reactive power Qm in a state where reactive power output is started, the magnitude of voltage change Δv2 _i , and the like. For example, it is conceivable to set the threshold value Sqs in the range of about 0.05 to 0.1, but the value of the threshold value Sqs is not limited to this, and may be a value larger or smaller than this.

When the voltage sensitivity Sq _i is larger than the threshold value Sqs (Sq _i > Sqs) (S2-16; No), the step of reducing the reactive power output for subsidy by the distributed power source B in a stepwise manner (S2 Return to -12).

On the other hand, when the voltage sensitivity Sq _i is equal to or less than the threshold value Sqs (Sq _i ≦ Sqs) (S2-16; Yes), the distributed power source B stops the reduction of the reactive power output for subsidy (S2-17). .

In the above, when the distributed power source A shifts from the voltage increase suppression control to the voltage constant control, the voltage control is performed not only in the voltage increase direction but also in the voltage decrease direction. This is based on the idea that the system impedance viewed from the distributed power source B connected to the electric wire 3 is lowered. In other words, when the voltage sensitivity Sq _i with respect to the reactive power change is reduced, it is determined that the distributed power source A has shifted to the constant voltage control, and the distributed power source B reduces the reactive power output for subsidy. It will stop.

  Here, for the distributed power source A, when the distributed power source B gradually reduces the reactive power output for subsidization (S2-12), voltage increase suppression control by the reactive power output is started accordingly (S1). -3) Increase until the phase advance reactive power output of the distributed power source A reaches the upper limit of the reactive power output (S1-4, S1-5; No).

  When the reactive power output of the distributed power source A reaches the upper limit (S1-5; Yes), the distributed power source A shifts to constant voltage control that also suppresses the voltage drop at the interconnection point 5a (S1-). 6).

  Through the above processing, the sharing of reactive power is completed.

  Furthermore, as a process for stopping the reactive power output for the subsidy, for the control of the distributed power source B, after the distributed power source B stops the reduction of the reactive power output for the subsidy (S2-17), The reactive power output is periodically changed. Then, the voltage sensitivity Sqf with respect to the reactive power fluctuation when the reactive power output is periodically changed is compared with the threshold value Sqs ′ for determining whether or not to stop the reactive power output for assistance (S2−). 18).

  The magnitude of the fluctuation of the reactive power is not limited as long as it does not affect the increase or decrease of the voltage of the distribution system 1. For example, the operator can appropriately consider the magnitude of the voltage at the interconnection point 5b. Set the size. Specifically, for example, it is conceivable to vary the voltage detected at the interconnection point 5b by a width of about 0.1%.

  In this embodiment, the threshold value Sqs ′ is the same as the threshold value Sqs for determining whether or not to stop the reduction of the reactive power output for the subsidy used in S2-16. However, the value of the threshold value Sqs ′ is not limited to this, and may be the same value as the threshold value Sqs or a different value, and may be a value that is larger or smaller than the threshold value Sqs.

  The calculation of the voltage sensitivity Sqf with respect to the reactive power fluctuation is the same as the calculation of the voltage sensitivity Sq with respect to the reactive power change described above. 6, reactive power is calculated from (Equation 5) from the detected voltage and current, a variation in reactive power is calculated from (Equation 7) from the calculated reactive power, and further, from the detected voltage (Equation 6) The voltage fluctuation Sqf is calculated from the calculated voltage fluctuation and the reactive power fluctuation by (Equation 8).

  When the voltage sensitivity Sqf is larger than the threshold value Sqs ′ (S2-18; Yes), the distributed power source B stops the reactive power output for the subsidy (S2-19).

  On the other hand, when the voltage sensitivity Sqf is equal to or less than the threshold value Sqs ′ (S2-18; No), the reactive power output is periodically varied, and the voltage sensitivity Sqf for the reactive power variation is calculated and compared with the threshold value Sqs ′. It returns to a process (S2-18).

  Preferably, the processes from S2-11 to S2-17 are performed after the process of S2-10, but the process of S2-18 is performed after the process of S2-10. Also good.

  The above is based on the idea that the distributed power source A is switched to the constant power source again when the constant voltage control is released, and the system impedance viewed from the distributed power source B connected to the same distribution line 3 is restored. It is based on. In other words, when the voltage sensitivity Sqf with respect to the reactive power fluctuation increases, it is determined that the distributed power source A connected to the same distribution line has canceled the constant voltage control, and the distributed power source B is subsidized. Therefore, the reactive power output is stopped.

  As for the control of the distributed power source A, after the distributed power source A shifts to the constant voltage control (S1-6), the reactive power output is compared with the reactive power output threshold (S1-7). When the reactive power output falls below the reactive power output threshold (S1-7; Yes), the distributed power source A cancels the constant voltage control (S1-8).

  On the other hand, when the reactive power output is equal to or greater than the reactive power output threshold (S1-7; No), the process returns to the step of comparing the reactive power output with the reactive power output threshold (S1-7).

  For example, the reactive power output threshold value may be about 10% of the maximum reactive power output, but is not limited thereto, and may be larger or smaller.

  In addition, the distributed power source A that has released the constant voltage control and the distributed power source B that has stopped the reactive power output for the subsidy also perform normal operation and return to the state of S0. Or subsidize by reactive power output.

  The above-described voltage control method and apparatus for the distribution system can also be realized by executing the voltage control program 13 on a computer. An example of this implementation is shown below.

  FIG. 3 shows the overall configuration of the voltage control device 7 for executing the voltage control program 13. The voltage control device 7 includes a control unit 8, a storage unit 9, an input unit 10, a display unit 11, and a memory 12, and is connected to each other by a signal line such as a bus. Further, the voltage / current detection device 6 and the distributed power source A or B are connected to the voltage control device 7 through a communication line or the like, and transmission / reception of signals such as data and control commands to / from each other via the communication line ( Input / output). The voltage control device 7 independently controls one distributed power source, and one voltage control device 7 is connected to each of the distributed power sources A and B.

  The control unit 8 performs a calculation related to the control of the entire voltage control device 7 and the voltage control of the distribution system 1 by the voltage control program 13 stored in the storage unit 9, and is a CPU, for example. The storage unit 9 is a device that can store at least data and programs, and is, for example, a hard disk. The input unit 10 is an interface for giving at least an operator command to the CPU, and is, for example, a keyboard. The display unit 11 displays characters, graphics, and the like under the control of the control unit 8 and is, for example, a display. The memory 12 becomes a memory space that becomes a work area when the control unit 8 executes various controls.

  The control unit 8 of the voltage control device 7 executes the voltage control program 13 to change the voltage comparison unit 8a that compares the voltage with the upper limit of the standard value of the distribution system, the normal operation state, and the output of the active power. Active power calculation unit 8b for calculating the active power in the state, a first reactive power output comparison unit 8c for comparing the reactive power output and the upper limit value of the reactive power output, the reactive power output and the reactive power output threshold A second reactive power output comparison unit 8d that performs comparison, a first change calculation unit 8e that calculates a change in voltage and a change in active power, and a first voltage sensitivity that calculates voltage sensitivity for the change in active power The calculation unit 8f, the first voltage sensitivity comparison unit 8g that compares the voltage sensitivity with a threshold value for determining whether or not to support the reactive power output, the state where the reactive power output is started, and the reactive power output are reduced. No let Reactive power calculation unit 8h that calculates power, a second change calculation unit 8i that calculates a change in voltage and a change in reactive power, and a second voltage sensitivity calculation unit that calculates voltage sensitivity for the change in reactive power 8j, the second voltage sensitivity comparison unit 8k that compares the voltage sensitivity with a threshold value for determining whether to stop the decrease in reactive power output, and determines whether to stop the voltage sensitivity and reactive power output A third voltage sensitivity comparison unit 8m that performs comparison with a threshold value and a control command output unit 8n that outputs a control command to the distributed power source are configured.

  The voltage control program 13 sets the voltage vsa and the current Isa in the normal operation state for the control of the distributed power source A, and the normal operation state for the control of the distributed power source B, at a time interval defined in advance in the program. The voltage vsb and current Isb are input from the voltage / current detection device 6 via a communication line or the like and stored in the storage unit 9 or the memory 12 (S1).

  Next, the voltage comparison unit 8a of the control unit 8 reads the voltages vsa and vsb stored in the storage unit 9 or the memory 12 in S1. Further, the upper limit value of the standard value of the distribution system 1 is read. Then, the voltages vsa and vsb are compared with the upper limit of the standard value of the distribution system 1 (S2). Here, as the upper limit value of the standard value, for example, a value input in advance by the input unit 10 and stored in the storage unit 9 is read.

  In the present embodiment, since the voltage vsa exceeds the upper limit of the standard value of the distribution system 1 (S2; Yes) in accordance with the above-mentioned assumption, the control command output is based on the comparison result of the voltage comparison unit 8a of the control unit 8. The unit 8n outputs to the distributed power source A a control command with a content for starting the voltage rise suppression control by the reactive power output (S1-3). Further, the contents of this control command are stored in the storage unit 9 or the memory 12 as necessary.

  On the other hand, since the voltage vsb does not exceed the upper limit of the standard value of the distribution system 1 (S2; No), the active power calculation unit 8b of the control unit 8 controls the storage unit 9 or the control unit 8 in S1 for the control of the distributed power source B. The voltage vsb and current Isb stored in the memory 12 are read. Then, the active power Ps in the normal operation state is calculated from (Equation 1) (S2-3). Further, the calculated active power Ps is stored in the storage unit 9 or the memory 12.

  Next, regarding the change in the output of the active power of the distributed power source B (S2-4), if the output is intentionally changed in order to perform the voltage control of the present invention, the control command of the control unit 8 The output unit 8n outputs to the distributed power source B a control command whose content is changed.

  Next, the active power calculation unit 8b of the control unit 8 inputs the values of the voltage vc and the current Ic from the voltage / current detection device 6 through a communication line or the like, and changes the output of the active power according to (Equation 1). The active power Pc in the selected state is calculated (S2-5). Then, the input voltage vc and current Ic and the calculated active power Pc are stored in the storage unit 9 or the memory 12.

  Next, the first change calculation unit 8e of the control unit 8 calculates the voltage change Δv1 and the active power change ΔP (S2-6). The first change calculation unit 8e of the control unit 8 first reads the voltage vsb stored in the storage unit 9 or the memory 12 in S1 and the voltage vc stored in the storage unit 9 or the memory 12 in S2-5. Then, the voltage change Δv1 is calculated by (Equation 2). Subsequently, the first change calculation unit 8e of the control unit 8 stores the effective power Ps stored in the storage unit 9 or the memory 12 in S2-3 and the effective power stored in the storage unit 9 or the memory 12 in S2-5. Read Pc. Then, the change ΔP of the active power is calculated by (Equation 3). The calculated voltage change Δv 1 and active power change ΔP are stored in the storage unit 9 or the memory 12.

  Next, the first voltage sensitivity calculation unit 8f of the control unit 8 reads the voltage change Δv1 and the active power change ΔP stored in the storage unit 9 or the memory 12 in S2-6, according to (Equation 4). The voltage sensitivity Sp with respect to the active power change is calculated (S2-7). The voltage sensitivity Sp corresponding to the calculated change in active power is stored in the storage unit 9 or the memory 12.

  Next, the first voltage sensitivity comparison unit 8g of the control unit 8 compares the voltage sensitivity Sp with a threshold value Sps for determining whether or not to perform subsidy by reactive power output (S2-8). The first voltage sensitivity comparison unit 8g of the control unit 8 first reads the voltage sensitivity Sp for the active power change stored in the storage unit 9 or the memory 12 in S2-7. In addition, a threshold value Sps for determining whether or not subsidy by reactive power output is performed is read. Here, as the value of the threshold Sps, for example, a value input in advance by the input unit 10 and stored in the storage unit 9 is read.

  When the voltage sensitivity Sp is larger than the threshold value Sps (Sp> Sps) (S2-8; No), the control command output unit 8n is based on the comparison result of the first voltage sensitivity comparison unit 8g of the control unit 8. Outputs a control command to the distributed power source B with the content of continuing normal operation without subsidy by reactive power output (S2-9). Further, the contents of this control command are stored in the storage unit 9 or the memory 12 as necessary.

  On the other hand, when the voltage sensitivity Sp is equal to or less than the threshold value Sps (Sp ≦ Sps) (S2-8; Yes), the control command output unit 8n is based on the comparison result of the first voltage sensitivity comparison unit 8g of the control unit 8. A control command for starting subsidy by reactive power output is output to the distributed power source B (S2-10). Further, the contents of this control command are stored in the storage unit 9 or the memory 12 as necessary. Here, it is preferable that the control command output unit 8n outputs a control command having a content for starting subsidy by the maximum reactive power output that can be output to the distributed power source B. Further, when the reactive power output for subsidization by the distributed power source B is automatically stopped after a predetermined time has elapsed from the start of output, the control command output unit 8n of the control unit 8 The control command is output to stop the reactive power output for the subsidy to the distributed power source B after a predetermined time elapses.

  Next, the reactive power calculation unit 8h of the control unit 8 inputs the values of the voltage vm and the current Im from the voltage / current detection device 6 through a communication line or the like, and starts reactive power output according to (Equation 5). The reactive power Qm is calculated (S2-11). Then, the input voltage vm and current Im, and the calculated reactive power Qm are stored in the storage unit 9 or the memory 12.

  Next, the control command output unit 8n of the control unit 8 outputs to the distributed power source B a control command with a content that gradually reduces the reactive power output for subsidy (S2-12). Here, the range of decrease when the reactive power output is decreased stepwise is, for example, a value that is input in advance by the input unit 10 and stored in the storage unit 9 is read.

Next, the reactive power calculation unit 8h of the control unit 8 inputs the values of the voltage v _i and the current I _i from the voltage / current detection device 6 through a communication line, etc. The reactive power Q _i in a state where the power output is lowered is calculated (S2-13). The input voltage v _i and current I _i and the calculated reactive power Q _i are stored in the storage unit 9 or the memory 12. Note that the subscript i is the number of stepwise reductions in the reactive power output of the distributed power source B (i = 1, 2, 3,...), And the storage unit 9 or the memory 12 stores a value for each number of times. Hereinafter, a case where the number of times of stepwise output reduction of the reactive power of the distributed power source B is i will be described.

Next, a second variation calculation section 8i of the control unit 8 calculates the change amount Delta] Q _i of the reactive power for voltage _{v i} and disabled variation .DELTA.v2 _i of the voltage for the power _{Q i} (S2-14). The second change calculation unit 8i of the control unit 8 first reads the voltages v _i and v _i−1 stored in the storage unit 9 or the memory 12 in S2-13. Note that the v ₀ in the case of the calculation of the first gradual reduction of the reactive power output (i = 1), reads the vm stored in the storage unit 9 or the memory 12 in S2-11. Then, a change Δv2 _{i in} voltage is calculated by (Equation 6). Subsequently, the second change calculation unit 8i of the control unit 8 reads the reactive power Q _i and Q _i−1 stored in the storage unit 9 or the memory 12 in S2-13. Note that the Q ₀ in the case of the calculation of the first gradual reduction of the reactive power output (i = 1), reads the Qm stored in the storage unit 9 or the memory 12 in S2-11. Then, the change ΔQ _i of the reactive power is calculated by (Equation 7). The calculated voltage change Δv2 _i and reactive power change ΔQ _i are stored in the storage unit 9 or the memory 12.

Next, the second voltage sensitivity calculation unit 8j of the control unit 8 reads the voltage change Δv2 _i and the reactive power change ΔQ _i stored in the storage unit 9 or the memory 12 in S2-14. Then, the voltage sensitivity Sq _i with respect to the reactive power change is calculated by (Equation 8) (S2-15). The voltage sensitivity Sq _i for the calculated reactive power change is stored in the storage unit 9 or the memory 12.

Next, the second voltage sensitivity comparison unit 8k of the control unit 8 compares the voltage sensitivity Sq _i with a threshold value Sqs for determining whether or not to stop the reduction of the reactive power output for subsidy (S2). -16). First, the second voltage sensitivity comparison unit 8k of the control unit 8 reads the voltage sensitivity Sq _i for the reactive power change stored in the storage unit 9 or the memory 12 in S2-15. In addition, a threshold value Sqs for determining whether or not to stop the reduction in reactive power output for subsidy is read. Here, as the value of the threshold value Sqs, for example, a value input in advance by the input unit 10 and stored in the storage unit 9 is read.

When the voltage sensitivity Sq _i is larger than the threshold value Sqs (Sq _i > Sqs) (S2-16; No), S2-12 is based on the comparison result of the second voltage sensitivity comparison unit 8k of the control unit 8. Returning to the step, the control command output unit 8n of the control unit 8 outputs to the distributed power source B a control command having a content that further reduces the reactive power output. Further, the contents of this control command are stored in the storage unit 9 or the memory 12 as necessary.

On the other hand, when the voltage sensitivity Sq _i is equal to or less than the threshold value Sqs (Sq _i ≦ Sqs) (S2-16; Yes), based on the comparison result of the second voltage sensitivity comparison unit 8k of the control unit 8, the control command output unit 8n outputs to the distributed power source B a control command with a content to stop the reduction of reactive power output for subsidy (S2-17). Further, the contents of this control command are stored in the storage unit 9 or the memory 12 as necessary.

  Here, regarding the control of the distributed power source A, after the distributed power source A starts the voltage increase suppression control by the reactive power output (S1-3), the first reactive power output comparison unit 8c of the control unit 8 outputs the reactive power output. And the magnitude of reactive power output from the distributed power source A is input via a communication line or the like. Then, the reactive power output is compared with the upper limit value of the reactive power output (S1-5). Here, as the upper limit value of the reactive power output, for example, a value input in advance by the input unit 10 and stored in the storage unit 9 is read.

  When the reactive power output of the distributed power source A reaches the upper limit value of the reactive power output (S1-5; Yes), the control command output unit 8n of the control unit 8 drops in voltage with respect to the distributed power source A. A control command with the content of transition to constant voltage control that also performs suppression is output (S1-6).

  On the other hand, when the reactive power output of the distributed power source A has not reached the upper limit value of the reactive power output (S1-5; No), the first reactive power output comparing unit 8c of the control unit 8 is the distributed power source A. The process returns to the step (S1-5) for comparing the reactive power output input through the communication line or the like with the upper limit value of the reactive power output.

  With the above process, the voltage control program 13 completes the process of sharing reactive power.

  Furthermore, as a process for stopping the reactive power output for the subsidy, for the control of the distributed power source B, after the distributed power source B stops the reduction of the reactive power output for the subsidy (S2-17), The control command output unit 8n of the control unit 8 outputs a control command with a content of periodically changing the reactive power to the distributed power source B. Then, the voltage sensitivity Sqf with respect to the reactive power fluctuation when the reactive power output is periodically changed is compared with the threshold value Sqs ′ for determining whether or not to stop the reactive power output for the subsidy (S2). -18).

  First, the third voltage sensitivity comparison unit 8m of the control unit 8 calculates the voltage sensitivity Sqf for the reactive power fluctuation. Since the calculation of the voltage sensitivity Sqf is the same as the calculation of the voltage sensitivity Sq with respect to the reactive power change, the details are omitted here. Further, a threshold value Sqs ′ for determining whether or not to stop the reactive power output for subsidy is read. Here, as the value of the threshold value Sqs ′, for example, a value that is input in advance by the input unit 10 and stored in the storage unit 9 is read.

  When the voltage sensitivity Sqf is larger than the threshold value Sqs ′ (S2-18; Yes), the control command output unit 8n is based on the comparison result of the third voltage sensitivity comparison unit 8m of the control unit 8, and the distributed power source A control command for stopping the reactive power output for subsidy is output to B (S2-19).

  On the other hand, when the voltage sensitivity Sqf is equal to or less than the threshold value Sqs ′ (S2-18; No), the control command output unit 8n of the control unit 8 controls the content that causes the distributed power source B to vary the reactive power periodically. While outputting a command, the third voltage sensitivity comparison unit 8m returns to the step (S2-18) in which the voltage sensitivity Sqf is calculated and the voltage sensitivity Sqf is compared with the threshold value Sqs ′.

  Regarding the control of the distributed power source A, after the distributed power source A shifts to the constant voltage control (S1-6), the second reactive power output comparison unit 8d of the control unit 8 outputs the reactive power output from the distributed power source A. Is input via a communication line or the like. Also, the reactive power output threshold is read. Here, as the reactive power output threshold, for example, a value input in advance by the input unit 10 and stored in the storage unit 9 is read.

  When the reactive power output of the distributed power source A is lower than the reactive power output threshold (S1-7; Yes), the control command output unit 8n of the control unit 8 controls the voltage of the distributed power source A to be constant. A control command with the content of canceling is output (S1-8).

  On the other hand, when the reactive power output of the distributed power source A is greater than or equal to the reactive power output threshold (S1-7; No), the second reactive power output comparing unit 8d of the control unit 8 communicates from the distributed power source A to a communication line or the like. The process returns to the step of comparing the reactive power output input via the reactive power output threshold (S1-7).

  In addition, although the above-mentioned form is an example of the suitable form of this invention, it is not limited to this, A various deformation | transformation implementation is possible in the range which does not deviate from the summary of this invention.

It is a flowchart which shows an example of embodiment of the voltage control method, apparatus, and program of a power distribution system of this invention. It is a figure explaining the power distribution system of embodiment. It is a functional block diagram of the voltage control apparatus in the case of implementing the voltage control method of the power distribution system of this embodiment using a program. It is a figure explaining the relationship of the two distributed power supplies linked to the same power distribution system, and the flow of each operation | movement.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Distribution system 3 Distribution line 5a, 5b Connection point 6 Voltage / current detection apparatus 7 Voltage control apparatus 8 Control part 9 Memory | storage part 10 Input part 11 Display part 12 Memory 13 Voltage control program A, B Distributed type power supply

Claims (12)

  In a distribution system in which a plurality of distributed power sources are connected to a distribution line, the change in active power and the change in voltage at the connection point between the distribution line and the distributed power source B When the voltage sensitivity is calculated and the voltage sensitivity with respect to the change in the active power is equal to or less than a threshold value for determining whether or not to perform subsidy by reactive power output, the other distributed power source A has shifted to the voltage rise suppression control. A voltage control method for a power distribution system, characterized in that the distributed power source B starts subsidy by reactive power output.   2. The distribution system voltage control method according to claim 1, wherein subsidy by the reactive power output at a maximum output that can be output by the distributed power source B is started.   After the distributed power source B starts subsidy by reactive power output, voltage sensitivity for reactive power change is calculated from the reactive power change and voltage change at the interconnection point, and the reactive power change If the voltage sensitivity is greater than a threshold for determining whether to stop the reduction of the reactive power output for the subsidy, the distributed power source B gradually reduces the reactive power output for the subsidy, When the voltage sensitivity to the reactive power change is equal to or less than a threshold for determining whether or not to stop the reduction of the reactive power output for the subsidy, it is determined that the distributed power source A has shifted to constant voltage control. The distribution system voltage control method according to claim 1, wherein the distributed power source B stops a reduction in reactive power output for subsidy.   After the distributed power source B starts subsidy with reactive power output, or after the distributed power source B stops reducing the reactive power output for subsidy, the variation of reactive power and voltage at the interconnection point When the voltage sensitivity for the reactive power fluctuation is calculated from the change and the voltage sensitivity for the reactive power fluctuation is greater than a threshold for determining whether to stop the reactive power output for the subsidy, the variance is The distributed power source B stops the reactive power output for subsidy when it is determined that the type power source A has released the voltage increase suppression control or the constant voltage control that has been shifted after the voltage increase suppression control. The voltage control method of the distribution system as described in any one of 1-3.   Means for calculating the voltage sensitivity for the change in active power from the change in active power and the change in voltage at the connection point between the distribution line and the distributed power source, and the voltage sensitivity for the change in active power depends on the reactive power output A power distribution unit including a control device including means for outputting a control command with a content for starting the subsidy by reactive power output to the distributed power source when the value is equal to or less than a threshold for determining whether or not to perform the subsidy. System voltage controller.   The means for outputting a control command with a content for starting subsidy with reactive power output outputs a control command with a content for starting subsidy with reactive power output at the maximum output that can be output to the distributed power source. The voltage control device for a power distribution system according to claim 5.   The control device calculates a voltage sensitivity for the reactive power change from the reactive power change and the voltage change at the interconnection point; and the reactive power for substituting the voltage sensitivity for the reactive power change Means for outputting a control command with a content of stepwise reducing reactive power output for subsidy to the distributed power source when the threshold value is larger than a threshold for determining whether or not to stop the output reduction; and When the voltage sensitivity with respect to the reactive power change is equal to or less than the threshold for determining whether or not to stop the reduction of the reactive power output for the subsidy, the distributed power source is reduced in the reactive power output for subsidy. The voltage control device for a distribution system according to claim 5 or 6, further comprising means for outputting a control command for the content to be stopped.   The control device calculates a voltage sensitivity for the reactive power fluctuation from the reactive power fluctuation and the voltage change at the interconnection point; and the reactive power for substituting the voltage sensitivity for the reactive power fluctuation And a means for outputting a control command with a content to stop reactive power output for subsidization to the distributed power source when the threshold value is larger than a threshold value for determining whether or not to stop the output. Item 8. The voltage control device for a power distribution system according to any one of Items 5 to 7.   Means for calculating a voltage sensitivity for an active power change from at least a change in active power and a change in voltage at a connection point between a distribution line and a distributed power source; and a voltage sensitivity for the active power change. Voltage of the distribution system for functioning as a means for outputting a control command for starting the subsidy by reactive power output to the distributed power source when it is below a threshold for determining whether or not subsidy by reactive power output is performed Control program.   10. The voltage control program for a distribution system according to claim 9, which causes the computer to function as means for outputting a control command with a content for starting subsidy by reactive power output at a maximum output that can be output to the distributed power source.   Means for calculating a voltage sensitivity for the reactive power change from the change of the reactive power and the voltage change at the interconnection point; the voltage sensitivity for the reactive power change is a reactive power output for subsidy. Means for outputting a control command with a content for stepwise reducing reactive power output for subsidization to the distributed power source when the threshold value is larger than a threshold value for determining whether or not to stop the reduction, the reactive power change Content that causes the distributed power source to stop reducing the reactive power output for the subsidy when the voltage sensitivity to the minute is equal to or less than the threshold for determining whether to stop the reduction of the reactive power output for the subsidy The voltage control program for a power distribution system according to claim 9 or 10 for functioning as means for outputting a control command. Means for calculating the voltage sensitivity for the reactive power fluctuation from the fluctuation of the reactive power and the voltage change at the interconnection point; and the reactive power output for substituting the voltage sensitivity for the reactive power fluctuation. The function according to claim 9 to 11 for causing the distributed power source to function as a means for outputting a control command for stopping the reactive power output for subsidy when the threshold value is larger than a threshold value for determining whether to stop or not. The voltage control program of the power distribution system as described in any one.

Images