JP6533969B2 - Voltage unbalance suppression support method and voltage unbalance suppression support device - Google Patents

Description

  The present invention relates to a voltage unbalance suppression support method for a three-phase distribution system, and a voltage unbalance suppression support device.

  In a three-phase distribution system, distribution lines for transmitting three-phase AC power are arranged horizontally or vertically, and the power demand for general homes, factories, shops, etc., via pole transformers installed in the distribution area The house is supplied with three-phase or single-phase AC power. The pole transformer is connected to any two-phase distribution line of the three-phase distribution line. Hereinafter, the single-phase portion after the pole transformer is also referred to as "single-phase load". Moreover, two phases to which single phase load is connected are also called "connection phase" hereafter.

  When a plurality of single-phase loads are connected together in one connection phase, the current unbalance increases and the degree of voltage unbalance of the three-phase alternating voltage increases. For this reason, the connection phase of each single-phase load is determined and each phase current is determined so that the sum (hereinafter, also referred to as "total capacity") of the load capacities of each single-phase load connected to each connection phase becomes equal. It is common to balance. The voltage unbalance that occurs due to the unequal total capacity of the connection phases is hereinafter also referred to as "voltage unbalance due to unequal load distribution".

  Further, in the three-phase distribution system, since the distances between the three-phase distribution lines arranged horizontally or vertically are different from each other, mutual reactance components generated between the distribution lines are not symmetrical, and the line impedance is not good. Equilibrium occurs and causes voltage imbalance. The voltage unbalance caused by the unbalance of the line impedance is hereinafter also referred to as “voltage unbalance due to asymmetry of phase arrangement”.

  When performing voltage unbalance analysis in such a three-phase distribution system, it is necessary to manage the information of the facilities that constitute the three-phase distribution system as individual data, and reproduce the distribution system model with these many data However, when changing the calculation conditions, a large amount of data must be adjusted individually, which is not practical. Patent Document 1 describes a technique of a contraction model creating method of contracting a distribution system model while maintaining a certain analysis accuracy.

Patent No. 48 31 479

  Conventionally, as a method for suppressing voltage unbalance in a three-phase distribution system, for example, a pseudo load device such as a single-phase capacitor is installed on the line end side to compensate for voltage unbalance, or It is common to perform a twist to change the arrangement of each distribution line of three phases.

  In distribution lines of average line length, in general, unequal load distribution of single-phase load has a significant influence as a factor of occurrence of voltage unbalance. In the case of a long distribution line where the line length becomes long, in particular, when the line length exceeds 20 km, the degree of voltage unbalance due to the asymmetry of the phase arrangement becomes large. In addition, if there are multiple line sections in which a plurality of lines are laid in parallel, the influence from the other lines causes an expansion of voltage unbalance.

  Essentially, when power quality problems occur, measures appropriate to the cause should be implemented. For example, in the case where the load distribution is uneven, this is a measure to equalize the load distribution, and in the case where the phase arrangement asymmetry is a cause, it is a measure to make the phase arrangement such as torsion symmetrical. In long-distance distribution systems, these factors combine to generate voltage unbalance at the end of the line, so for the purpose of simply suppressing voltage unbalance occurring at the end of the line, single-phase capacitors etc. If the pseudo load equipment is installed, the imbalance is superficially suppressed while the degree of each generation factor is unknown, and it can not be said that the voltage imbalance can be properly managed. In addition, when a system change occurs (for example, when only the phase alignment factor is eliminated), it is not always possible to suppress the voltage unbalance appropriately.

  The present invention has been made in view of the above, and provides a voltage imbalance suppression support method and voltage imbalance suppression support device capable of appropriately and sufficiently suppressing voltage imbalance in a three-phase distribution system.

  In order to solve the problems described above and achieve the object, the voltage imbalance suppression support method of the present invention outputs simulation results of a state in which voltage imbalance is suppressed in a line extended from a distribution substation. A first step of dividing the line into a first distribution section in which the current value is equal to or greater than a predetermined value and a second distribution section in which the current value is less than the predetermined value; Using the second step of simulating the first power distribution section as a voltage unbalance suppression target section in a state in which the voltage unbalance is suppressed, and using the simulation result in the second step, A third step of simulating a state in which voltage unbalance is suppressed as an unbalance suppression target section, and a fourth step of outputting simulation results in the second step and the third step And, with a.

  As a desirable mode of the present invention, in the second step, the voltage unbalance suppression processing is performed considering the single-phase load connected to the line as a three-phase balanced load.

  As a desirable mode of the present invention, the predetermined value is a value obtained by multiplying the output current of the distribution substation by a constant.

  As a desirable mode of the present invention, in the case where the first power distribution section includes a multi-line section juxtaposed with another line different from the line, the second step uses the contraction model of the other line in the second step. Perform voltage imbalance suppression processing.

  As a desirable mode of the present invention, in the second step, the voltage unbalance suppression processing is performed such that a voltage unbalance ratio indicating the degree of voltage unbalance becomes smaller at the downstream end of the first distribution section. .

  As a desirable mode of the present invention, in the second step, the phase arrangement of the three-phase distribution lines constituting the circuit is replaced at one or a plurality of locations at the end of each section obtained by dividing the first distribution section into a plurality of sections. Perform a simulation to carry out the rack process.

  As a desirable mode of the present invention, in the second step, a simulation is performed in which an imbalance suppression device is provided at the downstream end of the first power distribution section.

  In order to solve the problems described above and achieve the object, the voltage imbalance suppression support device of the present invention outputs a simulation result of a state in which voltage imbalance is suppressed in a line extended from a distribution substation. Voltage imbalance suppression unit, and a storage unit for storing the simulation result, wherein the voltage imbalance suppression unit is configured such that in the line, the first distribution section whose current value is equal to or greater than a predetermined value and the current value are The first distribution section is divided into a second distribution section which is less than the predetermined value, and the first distribution section is used as a voltage unbalance suppression target section to simulate a state in which voltage unbalance is suppressed, and the simulation result is A simulation result is stored in the storage unit, and the second distribution section is simulated as a voltage imbalance suppression target section using the first simulation result to simulate a state in which voltage imbalance is suppressed, The simulation result is stored in the storage unit as the second simulation result, and outputs the above stored in the storage unit the first simulation result and the second simulation result.

  As a desirable mode of the present invention, the voltage imbalance suppression unit performs single-phase load connected to the line when the voltage imbalance suppression processing is performed with the first distribution section as a voltage imbalance suppression target section. The voltage imbalance suppression processing is performed on the assumption that the load is a three-phase balanced load.

  According to the present invention, it is possible to provide a voltage unbalance suppression support method and a voltage unbalance suppression support device capable of appropriately and sufficiently suppressing voltage unbalance of a three-phase distribution system.

FIG. 1: is a figure which shows an example of the three-phase distribution system of object for which the voltage unbalance suppression support method which concerns on this embodiment is applied. FIG. 2 is a diagram showing an example of a connection portion between a line and a single phase load. FIG. 3 is a view showing an example of a pole in a horizontal single-line section in which three-phase distribution lines are horizontally arranged on the utility pole and installed. FIG. 4 is a diagram showing an example of a pole in a vertical single-line section in which three-phase distribution lines are vertically arranged on the utility pole and mounted. FIG. 5 is a diagram showing an example of a pole in a horizontal two-line section in which three-phase distribution lines of two lines are arranged horizontally in a utility pole and each array is installed in parallel. FIG. 6 is a view showing an example of a pole in a vertical two-line section in which each three-phase distribution line of two lines is arranged vertically in a utility pole and each array is installed in parallel. FIG. 7 is a diagram showing an equivalent circuit of a line in a no-load state. FIG. 8 is a voltage vector diagram showing an example of voltage unbalance generated by asymmetry of phase arrangement in a no-load state line. FIG. 9 is a diagram showing an equivalent circuit of a line in which a single phase load is connected to the ab phase. FIG. 10 is a voltage vector diagram showing an example of voltage imbalance generated due to load distribution imbalance in a circuit in which a single phase load is connected to the ab phase. FIG. 11 is a diagram showing an example of a functional block of the voltage imbalance suppression support device according to the present embodiment. FIG. 12 is a diagram showing an example of a line information table according to the present embodiment. FIG. 13 is a flowchart showing an example of the voltage unbalance suppression process in the voltage unbalance suppression support method according to the present embodiment. FIG. 14 is a diagram showing an example of a line information table of another line using a contraction model of the other line juxtaposed to the line to be analyzed according to the present embodiment.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited by the following embodiments (hereinafter referred to as embodiments). Further, constituent elements in the following embodiments include those which can be easily conceived by those skilled in the art, those substantially the same, and so-called equivalent ranges. Furthermore, the components disclosed in the following embodiments can be combined as appropriate.

  FIG. 1: is a figure which shows an example of the three-phase distribution system of object for which the voltage unbalance suppression support method which concerns on this embodiment is applied. In the three-phase distribution system 100, three-phase power is transmitted to a line 101 extended from a distribution transformer 200a installed in the distribution substation 200. In the following description, the distribution substation 200 side of the line 101 will be described as the upstream side and the opposite side as the downstream side.

  The distribution transformer 200a is, for example, a device that transforms the voltage on the primary side at a predetermined transformation ratio, and outputs the transformed voltage from the secondary side. It is assumed that the transformation ratio is set such that a voltage of, for example, 66 kilovolts is transformed to a voltage of 6.6 kilovolts, for example.

  The line 101 is a power line for supplying power from the distribution transformer 200a (upstream side) to each single-phase load 2, and for example, is mounted on a power pole (not shown) disposed at a predetermined interval. . The line 101 is a line to be subjected to voltage imbalance suppression processing to be described later, and includes a trunk 101-1 and branch lines 101-2 and 101-3 branched from the trunk 101-1.

  The line 101 is, for example, a plurality of sections 1-1 to 1-p, 2-9 to 2-q, 3 to 7 at arbitrary intervals with reference to the position of a utility pole (not shown) disposed at a predetermined interval. It is divided into -r, and is divided so that the branch point between the main line 101-1 and each branch line and the connection point of each single-phase load 2 become the downstream end of any section. In the example shown in FIG. 1, the downstream end of the sections 1-5, 1-7, 1-9, 1-p, 2-9, 2-q, 3-7, 3-9, 3-r is single. The phase load 2 is connected and branched to the branch line 101-3 at the downstream end of the section 1-6 of the trunk line 101-1, and to the branch line 101-2 at the downstream end of the section 1-8 of the trunk line 101-1. An example of branching is shown.

  The line 101 is a so-called long line in which the length of the trunk line 101-1 exceeds, for example, 20 km, and in the voltage imbalance suppression processing described later, the section 1-1 to section 1-5 It is divided | segmented into the 1st power distribution area containing, and the 2nd power distribution area containing the section 1-6-1-p, 2-9-2-q, and 3-7-3-r.

  Sections 1-1 to 1-4 are multi-line sections (two-line sections) in which another line 102 is juxtaposed to the line 101 to be subjected to the voltage imbalance suppression process. A plurality of single-phase loads 2 are connected to the line 102 on the downstream side of a point located at the downstream end of the section 1-4 of the line 101. In the voltage imbalance suppression process according to the present embodiment, the single-phase loads 2 connected to the line 102 and the downstream end of the section 1-4 of the line 101 from the single-phase loads 2 The distribution line up to the point may be contracted and regarded as a pseudo load 2 ′ connected to the point located at the downstream end of the section 1-4 of the line 101. A known technique can be used for the line reduction method. The present invention is not limited by this line reduction method.

  FIG. 2 is a diagram showing an example of a connection portion between a line and a single phase load. Here, a connection example of the line 101 and the single phase load 2 is shown.

  The line 101 is composed of three-phase distribution lines (hereinafter, also referred to as “distribution line a”, “distribution line b”, and “distribution line c”) each having phases a, b, and c. Three-phase AC power having the same amplitude of each line voltage and different in phase of the line voltage by 120 ° is supplied from the distribution transformer 200a to the three-phase distribution lines a, b, c.

  The single-phase load 2 is configured to include a transformer 21 connected to any two-phase distribution line among the distribution lines a, b and c, and a power load 22 connected to the transformer 21. .

  The transformer 21 is provided, for example, on a pole of a utility pole, transforms the voltage on the primary side at a predetermined transformation ratio, and outputs the transformed voltage from the secondary side. It is assumed that the transformer ratio is set such that a voltage of 6.6 kilovolts is transformed to a voltage of 100 volts or 200 volts, for example. FIG. 2 shows an example in which the primary side of the transformer 21 is connected to the distribution line a (a phase) and the distribution line b (phase b).

  The power load 22 is connected to the line 101 via the transformer 21. The electric power load 22 is, for example, via the pole transformer 21: two phases (ab phase) of a phase and b phase, two phases (bc phase) of b and c phases, c and a phases It operates by supplying electric power of any two phase (here, ab phase) among two phases (ca phase). Hereinafter, the two phases in which the power load 22 is connected via the transformer 21 are also referred to as “connection phase of the single phase load 2” or simply “connection phase”.

  It should be noted that, unlike the single-phase load 2 including the transformer 21 and the power load 22 described above, the description will be made of the three-phase balanced load which is operated by supplying three-phase power from three-phase distribution lines a, b, c. It is omitted for convenience.

  FIG. 3 is a view showing an example of a pole in a horizontal single-line section in which three-phase distribution lines are horizontally arranged on the utility pole and installed. In one horizontal line section, as shown in FIG. 3, the distribution lines a, b and c of the line 101 are arranged horizontally with respect to the ground and poled.

  FIG. 4 is a diagram showing an example of a pole in a vertical single-line section in which three-phase distribution lines are vertically arranged on the utility pole and mounted. In one vertical line section, as shown in FIG. 4, the distribution lines a, b and c of the line 101 are arranged vertically to the ground and poled.

  FIG. 5 is a diagram showing an example of a pole in a horizontal two-line section in which three-phase distribution lines of two lines are arranged horizontally in a utility pole and each array is installed in parallel. In the two horizontal line sections (multiple line sections), each distribution line a, b, c of the lines 101 arranged in the horizontal direction with respect to the ground and each distribution line of the lines 102 arranged in the horizontal direction with respect to the ground The d, e and f are parallel to each other.

  FIG. 6 is a view showing an example of a pole in a vertical two-line section in which each three-phase distribution line of two lines is arranged vertically in a utility pole and each array is installed in parallel. In the vertical two-line section (multi-line section), each distribution line a, b, c of the line 101 arranged in the direction perpendicular to the ground and each distribution line of the line 102 arranged in the direction perpendicular to the ground The d, e and f are parallel to each other.

  Next, voltage unbalance in the three-phase distribution system 100 will be described. In the three-phase distribution system 100, there are two causes of voltage unbalance, that is, the asymmetry of the phase arrangement and the unbalance of the load distribution. Here, “phase arrangement” refers to the positional relationship between the distribution lines a, b and c that make up the line 101, and “voltage imbalance due to asymmetry of the phase arrangement” means one horizontal line section or one vertical line. In the line section, the distribution lines a, b and c are arranged in a line, and in the horizontal two line sections and vertical two line sections (multi line sections), the lines from other distribution lines, etc. Refers to voltage imbalance caused by the asymmetry of the mutual impedance between them. Also, “load distribution” refers to the distribution of load capacity for each connection phase, and “voltage imbalance due to load distribution non-uniformity” means that the total capacity of single-phase loads connected to each connection phase is not sufficient. It refers to the voltage imbalance that results from becoming even.

  Here, voltage imbalance caused by asymmetry of the phase arrangement of the three phase distribution lines a, b and c in the line 101 will be described first with reference to FIGS. 7 and 8. FIG. 7 is a diagram showing an equivalent circuit of a line in a no-load state. FIG. 8 is a voltage vector diagram showing an example of voltage unbalance generated by asymmetry of phase arrangement in a no-load state line.

  In the example shown in FIG. 7, three-phase power is supplied from the left end side of the line 101. Hereinafter, the left end side of the line 101 is referred to as “upstream side”, and the right end side of the line 101 is referred to as “downstream side”.

  On the upstream side of the line 101, the amplitudes of the line voltages Vab, Vbc and Vca are equal, and the phases of the line voltages Vab, Vbc and Vca differ by 120 °. As a result, as shown in FIG. 8, the voltage vector diagram represented by the line voltage vector becomes a substantially equilateral triangle in which the line voltages Vab, Vbc, and Vca are balanced.

  Assuming that the resistance component of the line is R and the reactance component is X, a general expression of the line impedance is expressed as Z = R + jX (j is a complex symbol).

  As shown in FIG. 7, according to the distance between the respective distribution lines a, b and c, in the line 101 constituted by the three respective distribution lines a, b and c, the respective distribution lines a, b and c The inter-reactance components Xab, Xbc and Xac are generated between When the resistance components and reactance components of the distribution lines a, b and c are equal and the arrangement conditions of the distribution lines a, b and c are symmetrical, the inter-line voltages Va′b on the downstream side of the line 101 The equilibrium state of ', Vb'c', Vc'a 'is maintained.

  On the other hand, in the horizontal single line section and the vertical single line section, since the distribution lines a, b, c are arranged in a line, the magnitudes of the mutual reactance components Xab, Xbc, Xac generated between the lines are different. Thereby, as shown in FIG. 8, the voltage vector diagram represented by the line voltage vector is an irregular triangle in which the equilibrium state of each of the line voltages Va'b ', Vb'c' and Vc'a 'is broken. It becomes a shape. Furthermore, in the two horizontal line sections and the vertical two line sections, since the lines affect each other, an error occurs in the line impedance, and the error is caused to the imbalanced state in one horizontal line section or one vertical line section. It occurs.

  Next, with reference to FIGS. 9 and 10, voltage imbalance caused by load distribution imbalance will be described. FIG. 9 is a diagram showing an equivalent circuit of a line in which a single phase load is connected to the ab phase. FIG. 10 is a voltage vector diagram showing an example of voltage unbalance that occurs due to unequal load distribution in a circuit in which a single phase load is connected to the ab phase. In the example shown in FIGS. 9 and 10, in order to facilitate the description of the voltage imbalance caused by the uneven distribution of load, simplification is made without considering the influence of the above-described phase arrangement, that is, the mutual reactance component generated between the lines. ing.

  In the example shown in FIG. 9, the bc phase and the ca phase are unloaded. The voltage vector diagram at the connection point P with the single-phase load 2 is, as shown in FIG. 10, an irregular triangle in which the equilibrium state of each of the line voltages Va'b ', Vb'c' and Vc'a 'is broken. It becomes.

  Next, a voltage unbalance suppression support method and a voltage unbalance suppression support device according to the present embodiment will be described.

  FIG. 11 is a diagram showing an example of a functional block of the voltage imbalance suppression support device according to the present embodiment. As shown in FIG. 11, the voltage imbalance suppression support device 1 according to the present embodiment includes, for example, an input unit 11, an output unit 12, a display unit 13, a storage unit 14, a voltage imbalance suppression unit 15, and a control unit 16. It carries out the voltage unbalance suppression processing which simulates the voltage unbalance suppression countermeasure in the line designated by the operator, and outputs the simulation result.

  The input unit 11 is, for example, a keyboard for inputting information to the voltage imbalance suppression support device 1.

  The output unit 12 is, for example, a printer for outputting information to the outside of the voltage imbalance suppression support device 1.

  The display unit 13 is, for example, a monitor for displaying information input to the voltage imbalance suppression support device 1 or displaying information output from the voltage imbalance suppression support device 1.

  The storage unit 14 includes, for example, a first area 141 and a second area 142. The storage unit 14 is, for example, a ROM (Read Only Memory), a hard disk drive, a flash memory, or the like, or a combination thereof.

  In the first area 141, for example, a program for operating the voltage imbalance suppression support device 1 is stored. In the first area 141, for example, a program (hereinafter, also referred to as a "voltage unbalance suppression processing program") for suppressing voltage unbalance of long lines in a three-phase distribution system is stored. .

  In the second area 142, for example, a line information table T1 (FIG. 12), which is information on a line (for example, lines 101 and 102 shown in FIG. 1) unit in the three-phase distribution system, is stored. The line information table T1 will be described later.

  The voltage imbalance suppression unit 15 performs voltage imbalance suppression processing of the line designated via the input unit 11 based on the various information stored in the second area 142.

  The control unit 16 controls the operation of the voltage imbalance suppression support device 1 based on a program stored in the first area 141 for operating the voltage imbalance suppression support device 1, for example. In addition, the voltage imbalance suppression processing is executed by the voltage imbalance suppression unit 15 when the control unit 16 starts the voltage imbalance suppression processing program.

  The voltage imbalance suppression unit 15 and the control unit 16 can be configured by combining, for example, a CPU (Central Processing Unit) and a memory.

  FIG. 12 is a diagram showing an example of a line information table according to the present embodiment. The line information table T1 is set for each section and stored in the second area 142. Here, an example corresponding to the line 101 shown in FIG. 1 is shown, and this example will be described in the light of the line 101.

  The line information table T1 includes an output current, an output voltage, a distribution section determination coefficient K, a main line (101-1), and each branch line (substation output factor for supplying three-phase power to each line (for example, line 101 shown in FIG. Length of each section (1-1 to 1-p, 2-9 to 2-q, 3 to 7 to 3-r) of 101-2, 101-3), wire definition, electric circuit phase arrangement, load The capacitance, the load connection phase, and the output current are associated with one another and stored in the second area 142. Each information set in the line information table T1 may be set in advance according to the actual line laying state, or simulated by another process different from the voltage imbalance suppression process according to the present embodiment. For example, it can be set by the input unit 11, the voltage imbalance suppression unit 15, and the like. Also, the output current of each section may be calculated using, for example, a generally known power flow calculation method.

  A distribution section (a first distribution section, a second distribution section) in the line information table T1 is set in a voltage imbalance suppression process described later. Moreover, the electrical line phase arrangement | sequence of each area and load connection phase are suitably changed in the voltage unbalance suppression process mentioned later.

  The load capacity of each section is, for example, a capacity that is predetermined for each transformer that is connected to the downstream end of each section and supplies power to the power load included in the single-phase load. , Is a capacity determined based on the rating of each transformer. The distribution section determination coefficient K will be described later.

  FIG. 13 is a flowchart showing an example of the voltage unbalance suppression process in the voltage unbalance suppression support method according to the present embodiment.

(Step S1)
When the operator designates a line to execute the voltage imbalance suppression process and the control unit 16 starts the voltage imbalance suppression process program, the voltage imbalance suppression unit 15 first outputs the line 101 to the output current value. It divides into the 1st distribution section which becomes more than a predetermined value, and the 2nd distribution section which an output current value becomes less than a predetermined value.

  Specifically, the voltage imbalance suppression unit 15 reads out the substation output current, the output current value in each section of the main line, and the distribution section determination coefficient K from the line information table T1 of the specified line, and outputs Up to a section (here, section 1-) where the current value is equal to or greater than a value (here, 102 A) obtained by multiplying the power distribution section determination coefficient K (for example, K = 0.9) by the substation output current (here, 114 A). 5) are set as the first power distribution section, and the downstream side of the first power distribution section is set as the second power distribution section and stored in the line information table T1 (step S11). In the example shown in FIG. 1 and FIG. 12, the section 1-1 to the section 1-5 is the first power distribution section, and each section 1-6 to 1-p, 2-9 to the downstream side of the section 1-5 2-q and 3-7 to 3-r are the second power distribution section.

  In the present embodiment, the long-distance line in the three-phase distribution system is connected to the first distribution section where each single phase load connected is small and the asymmetry of the phase arrangement is large as a factor of voltage imbalance and each branch line. It branches into a number of single-phase loads connected, and is divided into a second distribution section that is largely affected by unequal load distribution as a factor of voltage unbalance.

  For example, a load concentration area such as a city area is assumed as an area where the second power distribution section is laid. In such a load concentration area, the distance between each single phase load tends to be short, and the section length tends to be short. For this reason, as a factor of voltage unbalance in a load concentration area, the influence by unequal distribution of load is larger than the influence by asymmetry of phase arrangement.

  Further, as an area where the first power distribution section is laid, for example, a load distribution area where a circuit is laid in a mountain area or the like in order to transmit power to a city area which is a load concentration area is assumed. In such a load sharing area, the distance between each single phase load tends to be long and the section length is long. For this reason, as a factor of voltage imbalance in the load distribution area, the effect due to the asymmetry of the phase arrangement is larger than the effect due to the load distribution unbalance. In addition, in the case where a multi-line section (two line sections) is included in the first power distribution section (sections 1-1 to 1-4 in the example shown in the figure), the power distribution lines of the voltage imbalance suppression processing target line are other There is an error in the line impedance under the influence of the line distribution line.

  Therefore, by carrying out voltage imbalance suppression processing by separating the load concentration area and the load distribution area, it is possible to suppress voltage unbalance due to uneven load distribution and voltage imbalance due to asymmetry of phase arrangement. Positioning becomes clearer than before, and it becomes possible to support voltage imbalance suppression so that appropriate and sufficient voltage imbalance suppression effect can be obtained.

  In the present embodiment, attention is paid to the fact that the decrease in output current is smaller than the length in the section where there are few single-phase loads connected, and a constant magnification of the substation output current (for example, distribution section determination coefficient K = 0 9) A section where the above current flows is the first distribution section, and a downstream side of the first distribution section is the second distribution section, and in the following steps S2 to S4, the first distribution section and the second distribution section respectively A suitable voltage imbalance suppression process is performed.

(Step S2)
Next, the voltage unbalance suppression unit 15 performs voltage unbalance suppression processing with the first power distribution section as a voltage unbalance suppression target section. In this step S2, a simulation is performed to eliminate the influence of the load distribution non-uniformity in the entire section of the designated line and to suppress the voltage unbalance caused by the asymmetry of the phase arrangement in the first distribution section. Therefore, in the following steps S21 and S22, processing is performed by regarding all single-phase loads connected to the designated line as three-phase balanced loads.

  Specifically, the voltage imbalance suppression unit 15 reads the section length for each section of the trunk line and the branch line, the wire definition, the electric line phase arrangement, the load capacity, and the like from the line information table T1 of the specified line. In the case where the first distribution section includes a multi-line section (two-line section) (in the example shown in the example, sections 1-1 to 1-4), the line information table of the other lines juxtaposed to the designated line From T1, the section length for each section of the main line and branch line, wire definition, electrical circuit phase arrangement, load capacity, etc. are read out, and the downstream end of the first distribution section set in step S1 based on these pieces of information. The voltage unbalance rate at is calculated (step S21).

  Here, the voltage unbalance rate is indicated by the ratio of the negative phase voltage to the positive phase voltage. The positive phase voltage and the negative phase voltage can be calculated, for example, using a generally known power flow calculation method.

  When the multi-line section (two-line section) is included in the first power distribution section, the process is performed using a reduction model in which other lines provided to the analysis target line are reduced. Here, specifically, the contraction model refers to a model in which a plurality of loads connected to other circuits and a part of an electric line connected to each load are reduced to one pseudo load. I assume.

  In the example shown in FIG. 1, the simulated load 2 is reduced by shortening the single-phase loads 2 connected to the line 102 and the electric lines of the line 102 on the downstream side of the section corresponding to the section 1-4 of the line 101. 'That. In this case, a reduction model is created on the assumption that the simulated load 2 'is connected to the downstream end of the section corresponding to the section 1-4 in the line 101, and the line information table of the line 102 using the reduction model T2 is stored in advance in the second area 142.

  FIG. 14 is a diagram showing an example of a line information table of another line using a contraction model of the other line juxtaposed to the line to be analyzed according to the present embodiment. When the multi-line section (two-line section) is included in the first distribution section, the section length for each section of the main line and the branch line read from the line information table T1 of the specified line in step S21 From the line information table T2 of the other line using the contraction model in addition to the definition, electric line phase arrangement, load capacity etc., section length for each section of the other line, electric line definition, electric line phase arrangement, simulated load The load capacity and the like are read out to calculate the voltage unbalance rate at the downstream end of the first distribution section. This makes it possible to reduce the amount of information of the other lines connected to the specified line, and to increase the analysis speed.

  Subsequently, the voltage unbalance suppression unit 15 performs a process to reduce the voltage unbalance ratio at the downstream end of the first power distribution section (step S22).

  Specifically, the voltage imbalance suppression unit 15 sets one or more torsion points in the first power distribution section so that the voltage unbalance rate at the downstream end of the first power distribution section becomes smaller. For example, when setting the boundary point between the section 1-2 and the section 1-3 as a twisting point, the electric line phase arrangement of the area 1-3 and the subsequent areas is changed, and the electric line phase arrangement of each changed area is It stores in table T1.

  Alternatively, the voltage imbalance suppression unit 15 sets an imbalance suppression device installed at the downstream end of the first power distribution section so that the voltage unbalance rate at the downstream end of the first power distribution section becomes smaller. This unbalance suppression device can be replaced with a pseudo load device such as a single phase capacitor, and the load capacity of the single phase load and the load connection phase corresponding to this unbalance suppression device are added to the line information table T1. For example, in the example illustrated in FIG. 1, the unbalance suppression device is to be juxtaposed with the single-phase load 2 at the downstream end of the section 1-5.

  A simulation capable of suppressing voltage unbalance caused by asymmetry of the phase arrangement in the first distribution section while eliminating the influence of unequal load distribution in the entire section of the designated line by the processing of step S2 above. The result is obtained.

(Step S3)
Next, based on the processing result in step S2, the voltage imbalance suppression unit 15 performs voltage imbalance suppression processing with the second power distribution segment as a voltage imbalance suppression target segment. In this step S3, by using a simulation result capable of suppressing voltage unbalance caused by asymmetry of the phase arrangement in the first distribution section obtained in step S2 described above, the asymmetry of the phase arrangement in the first distribution section With the influence eliminated, it is possible to simulate to suppress the voltage unbalance caused by the unequal load distribution in the second distribution section.

  Specifically, the voltage imbalance suppression unit 15 reads, from the line information table T1, the section length for each section of the main line and the branch line in the second distribution section, the wire definition, the electric line phase arrangement, the load capacity, etc. Based on these pieces of information, the voltage unbalance rate at each section end is calculated (step S31).

  Subsequently, the voltage imbalance suppression unit 15 determines the voltage unbalance rate at the end of each section in the second distribution section, or the average value or the maximum value of the voltage unbalance factor at each section end in the second distribution section. Is performed (step S32).

  Specifically, the voltage unbalance suppression unit 15 determines the voltage unbalance rate at the end of each section in the second distribution section, or the average value of the voltage unbalance factor at each section end in the second distribution section, or The connection phase of each single-phase load installed at the downstream end of each section is changed and stored in the line information table T1 so that the maximum value becomes smaller. In addition, as a connection phase setting method of each single phase load for suppressing voltage unbalance, a known technique can be used. The present invention is not limited by the connection phase setting method of each single-phase load.

  Alternatively, the voltage imbalance suppression unit 15 may calculate the voltage unbalance rate at the end of each section in the second distribution section, or the average value or the maximum value of the voltage unbalance factor at each section end in the second distribution section. Twist points are set at one or more points of each section end in the second power distribution section so as to be smaller. For example, when setting the boundary point between the section 1-8 and the section 1-9 as a twisting point, the electric line phase arrangement after the area 1-9 is changed, and the electric line phase arrangement of each changed area It stores in table T1.

  Alternatively, the voltage imbalance suppression unit 15 may calculate the voltage unbalance rate at the end of each section in the second distribution section, or the average value or the maximum value of the voltage unbalance factor at each section end in the second distribution section. The imbalance suppression device installed at one or more places at each end of each section in the second power distribution section is set so as to be smaller. This unbalance suppression device can be replaced with a pseudo load device such as a single phase capacitor, and the load capacity of the single phase load and the load connection phase corresponding to this unbalance suppression device are added to the line information table T1.

  By the above-described processing of step S3, a simulation result capable of suppressing voltage unbalance caused by unequal load distribution in the second distribution section is obtained, with the influence of asymmetry of the phase arrangement in the first distribution section being eliminated. Be

(Step S4)
Next, the voltage imbalance suppression unit 15 outputs the line information table T1 set in the above-described steps S1 to S3 as a processing result in the voltage imbalance suppression processing.

  Specifically, the voltage imbalance suppression unit 15 performs output processing such as displaying each piece of information of the line information table T1 set in steps S1 to S3 on the display unit 13 or outputting the information from the output unit 12 or the like. (Step S41), and the voltage imbalance suppression process is finished.

  As described above, in the voltage imbalance suppression support method according to the present embodiment, the single-phase load connected to the long-distance line in the three-phase distribution system is small, and the phase alignment is asymmetric as a factor of voltage imbalance. Divided into the first distribution section where the influence of the load is large, and the second distribution section where the branch lines are connected and many single-phase loads are connected, and the load distribution imbalance is large as a factor of voltage imbalance, Voltage imbalance suppression processing is performed with the first distribution section as the voltage imbalance suppression target section, and using the simulation results in the first distribution section, the voltage imbalance suppression processing is performed with the second distribution section as the voltage imbalance suppression target section Do. In this way, in a state where the suppression measures of voltage imbalance that are largely affected by the asymmetry of the phase arrangement in the first distribution section are simulated, the suppression of voltage imbalance that is largely affected by the unbalance of the load distribution in the second distribution section Since the measures are simulated, voltage imbalance in long-length circuits can be appropriately and sufficiently suppressed.

  Further, in the voltage imbalance suppression support method according to the present embodiment, the single-phase loads connected to the designated line are all replaced with three-phase balanced loads, and the voltage of the first distribution section is set as the voltage imbalance suppression target section. Unbalance suppression processing is performed, and then the load replaced with the three-phase balanced load is returned to a single-phase load, and voltage imbalance suppression processing is performed with the second distribution section as a voltage unbalance suppression target section. As a result, voltage imbalance suppression processing can be performed with the first distribution section as a voltage imbalance suppression target section while eliminating the influence of load distribution nonuniformity in all sections of the designated line, and With the influence of the asymmetry of the phase arrangement in the power distribution section eliminated, the voltage unbalance suppression processing can be performed with the second power distribution section as the voltage unbalance suppression target section.

  Further, in the voltage imbalance suppression support method according to the present embodiment, when the first power distribution section includes a multi-line section connected with a power distribution line of another line, the first power distribution is performed using a contraction model of the other line. The voltage unbalance suppression processing is performed with the section as a voltage unbalance suppression target section. This makes it possible to reduce the amount of information of the other lines connected to the specified line, and to increase the analysis speed.

  The voltage imbalance suppression support device according to the present embodiment includes a voltage imbalance suppression unit that performs voltage imbalance suppression processing and outputs the processing result of the voltage imbalance suppression processing, and the voltage imbalance suppression unit includes: A long distribution line in a three-phase distribution system is divided into a first distribution section where the single phase load to be connected is small and the asymmetry of the phase arrangement is large as a factor of voltage imbalance, and many branches are branched. A single-phase load is connected and divided into a second distribution section where the load distribution is highly affected by unequal load distribution as a factor of voltage imbalance, and voltage imbalance suppression processing is performed with the first distribution section as the voltage imbalance suppression target section. The voltage imbalance suppression processing is performed by using the simulation result in the first power distribution section, with the second power distribution section as a voltage unbalance suppression target section. In this way, in a state where the suppression measures of voltage imbalance that are largely affected by the asymmetry of the phase arrangement in the first distribution section are simulated, the suppression of voltage imbalance that is largely affected by the unbalance of the load distribution in the second distribution section Since the measures are simulated, voltage imbalance in long-length circuits can be appropriately and sufficiently suppressed.

  In addition, the voltage imbalance suppression support device according to the present embodiment replaces all single-phase loads connected to the designated line with three-phase balanced loads, and sets the first distribution section as a voltage imbalance suppression target section. Unbalance suppression processing is performed, and then the load replaced with the three-phase balanced load is returned to a single-phase load, and voltage imbalance suppression processing is performed with the second distribution section as a voltage unbalance suppression target section. As a result, voltage imbalance suppression processing can be performed with the first distribution section as a voltage imbalance suppression target section while eliminating the influence of load distribution nonuniformity in all sections of the designated line, and With the influence of the asymmetry of the phase arrangement in the power distribution section eliminated, the voltage unbalance suppression processing can be performed with the second power distribution section as the voltage unbalance suppression target section.

DESCRIPTION OF SYMBOLS 1 Voltage unbalance suppression support apparatus 2 single phase load 2 'Pseudo load 11 Input part 12 Output part 13 Display part 14 Memory | storage part 15 Voltage unbalance suppression part 16 Control part 21 Transformer 22 Electric load 100 Three-phase distribution system 101 Circuit ( Voltage unbalance suppression target line)
101-1 trunk line (voltage unbalance suppression target line)
101-2 Branch line (voltage unbalance suppression target line)
101-3 Branch line (voltage unbalance suppression target line)
102 lines (lines attached to some sections of the line subject to voltage imbalance suppression)
141 1st field 142 2nd field 200 Distribution substation 200a Distribution transformer

Claims (9)

A voltage imbalance suppression support method for outputting a simulation result of a state in which voltage imbalance is suppressed in a line extended from a distribution substation, comprising:
A first step of dividing the line into a first distribution section in which the current value is equal to or greater than a predetermined value and a second distribution section in which the current value is less than the predetermined value;
A second step of performing voltage unbalance suppression processing to simulate the state where voltage unbalance is suppressed, with the first distribution section as a voltage unbalance suppression target section;
A third step of simulating the second power distribution section as a voltage unbalance suppression target section using the simulation result in the second step, in a state where the voltage unbalance is suppressed;
Outputting a simulation result in the second step and the third step;
Have
Voltage imbalance suppression support method. In the second step,
The voltage unbalance suppression process is performed considering the single phase load connected to the line as a three phase balanced load.
The voltage imbalance suppression support method according to claim 1. The predetermined value is a value obtained by multiplying the output current of the distribution substation by a fixed number.
The voltage imbalance suppression support method according to claim 1. In the case where the first power distribution section includes a multi-line section juxtaposed with another line different from the line,
In the second step,
Performing the voltage imbalance suppression process using the reduction model of the other line;
The voltage imbalance suppression support method according to any one of claims 1 to 3. In the second step,
Performing the voltage unbalance suppression process such that a voltage unbalance ratio indicating a degree of voltage unbalance decreases at the downstream end of the first distribution section;
The voltage imbalance suppression support method according to any one of claims 1 to 4. In the second step,
A simulation is carried out to perform a twisting process in which the phase arrangement of the three-phase distribution lines constituting the circuit is replaced at one or a plurality of locations at the end of each section obtained by dividing the first distribution section into a plurality of sections.
The voltage imbalance suppression support method according to any one of claims 1 to 5. In the second step,
Carrying out a simulation of providing an imbalance suppression device at the downstream end of the first distribution section,
The voltage imbalance suppression support method according to any one of claims 1 to 5. A voltage imbalance suppression unit that outputs a simulation result of a state in which voltage unbalance is suppressed in a line extended from the distribution substation;
A storage unit that stores the simulation result;
Equipped with
The voltage imbalance suppression unit
Dividing the line into a first distribution section in which the current value is equal to or greater than a predetermined value and a second distribution section in which the current value is less than the predetermined value;
The first distribution section is a voltage unbalance suppression target section, and voltage unbalance suppression processing is performed to simulate a state where voltage unbalance is suppressed, and the simulation result is stored in the storage unit as a first simulation result. Remember
Using the first simulation result as the second distribution section as a voltage unbalance suppression target section, the second distribution section is simulated to a state in which voltage unbalance is suppressed, and the simulation result is used as the second simulation result. Stored in the storage unit,
Outputting the first simulation result and the second simulation result stored in the storage unit;
Voltage imbalance suppression support device. The voltage imbalance suppression unit
When the voltage unbalance suppression process is performed with the first distribution section as a voltage unbalance suppression target section, the single-phase load connected to the line is regarded as a three-phase balanced load and the voltage unbalance suppression process I do,
The voltage imbalance suppression support device according to claim 8.

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