JP2023044242A - Voltage unbalance suppression support method and voltage unbalance suppression support device - Google Patents

Abstract

To provide a voltage unbalance suppression support method and a voltage unbalance suppression support device that can simulate the suppression of voltage unbalance in a three-phase distribution line using a V-Y connection TVR.SOLUTION: Using a power flow calculation method, when voltage unbalance suppression simulation of a three-phase distribution line according to the placement position of a thyristor-type automatic voltage regulator is performed, a target voltage of a first phase voltage to ground of the thyristor-type automatic voltage regulator, a target voltage of a second phase voltage to ground, a target voltage of a third phase voltage to ground, the regulated first phase voltage to ground, the regulated second phase voltage to ground, the regulated third phase voltage to ground, the tap value of a voltage regulating transformer connected in parallel between the first and second phases, and the tap value of a voltage regulating transformer connected in parallel between the second and third phases are used to add a correction term to keep the neutral point voltage unchanged.SELECTED DRAWING: Figure 13

Description

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

In the distribution system, three-phase AC power is transmitted by mounting three-phase distribution lines in a horizontal or vertical arrangement, and through pole-mounted transformers installed in the distribution area, general households, factories, shops, etc. Power consumers are supplied with three-phase or single-phase AC power. A pole transformer is connected to any two of the three phases in a three-phase distribution line. The single-phase portion after the pole transformer is hereinafter referred to as "single-phase load".

When multiple single-phase loads are concentrated on two of the three phases of a three-phase distribution line, the current imbalance increases, causing a three-phase voltage imbalance of the three-phase AC voltage (hereinafter referred to as voltage imbalance). will increase. In order to cope with such voltage unbalance and voltage fluctuations in three-phase distribution lines, introduction of a thyristor type step voltage regulator (TVR) has been promoted in recent years (eg, Patent Document 1).

Japanese Patent No. 6666109

Conventionally, an automatic voltage regulator (SVR: Step Voltage Regulator) is installed as a countermeasure against voltage drop in a distribution system. The SVR does not have a function to suppress voltage imbalance because it switches the taps of all three phases at once. Voltage imbalance can be suppressed. In order to take countermeasures by installing equipment when voltage unbalance occurs in the distribution system, it is necessary to install equipment in appropriate locations. However, since the optimum installation position differs depending on the distribution system, in order to realize efficient operation, it is necessary to derive the optimum installation position of the TVR by simulation in advance.

The present invention has been made in view of the above, and provides a voltage unbalance suppression support method and a voltage unbalance suppression support that can realize suppression simulation of voltage unbalance in a three-phase distribution line using a VY connection TVR. The purpose is to provide an apparatus.

To achieve the above object, a voltage unbalance suppression support method according to one aspect uses a power flow calculation method to perform a voltage unbalance suppression simulation of a three-phase distribution line according to the arrangement position of a thyristor-type automatic voltage regulator. In the voltage unbalance suppression support method, the thyristor-type automatic voltage regulator includes a Y-connection series transformer having secondary windings connected in series to each of a first phase, a second phase, and a third phase; a V-connected voltage regulating transformer connected in parallel between the first phase and the second phase and between the second phase and the third phase, respectively; a secondary winding of the voltage regulating transformer; A thyristor tap changer connected to the primary winding of the series transformer, wherein E _a is the target voltage of the first phase voltage to ground, E _b is the target voltage of the second phase voltage to ground, and the third E _c is the target voltage of the phase voltage to ground, E _A is the adjusted first phase voltage to ground, E _B is the adjusted second phase voltage to ground, E _C is the adjusted third phase voltage to ground, _Rab the tap value of the voltage regulating transformer connected in parallel between the first and second phases, and a Rab the tap value of the voltage regulating transformer connected in parallel between the second and third phases When _Rbc , a voltage imbalance suppression simulation of the three-phase distribution line is performed using the following equations (1) and (2).

As a desirable aspect, the voltage imbalance of the three-phase distribution line is assumed to be arranged in one of a plurality of nodes from the distribution substation to the end of the three-phase distribution line. Equilibrium suppression simulation is performed.

As a desirable aspect, a voltage unbalance suppression simulation of the three-phase distribution line is performed for all of the plurality of nodes, assuming that the thyristor type automatic voltage regulator is arranged at one of the plurality of nodes. .

To achieve the above object, a voltage unbalance suppression support device according to one aspect uses a power flow calculation method to perform a voltage unbalance suppression simulation of a three-phase distribution line according to the arrangement position of a thyristor-type automatic voltage regulator. In a voltage imbalance suppression support device, the thyristor-type automatic voltage regulator includes a Y-connected series transformer having secondary windings connected in series to each of a first phase, a second phase, and a third phase; a V-connected voltage regulating transformer connected in parallel between the first phase and the second phase and between the second phase and the third phase, respectively; a secondary winding of the voltage regulating transformer; A thyristor tap changer connected to the primary winding of the series transformer, wherein E _a is the target voltage of the first phase voltage to ground, E _b is the target voltage of the second phase voltage to ground, and the third E _c is the target voltage of the phase voltage to ground, E _A is the adjusted first phase voltage to ground, E _B is the adjusted second phase voltage to ground, E _C is the adjusted third phase voltage to ground, _Rab the tap value of the voltage regulating transformer connected in parallel between the first and second phases, and a Rab the tap value of the voltage regulating transformer connected in parallel between the second and third phases When _Rbc , a voltage imbalance suppression simulation of the three-phase distribution line is performed using the following equations (1) and (2).

As a desirable aspect, the voltage unbalance suppression support device is based on the assumption that the thyristor-type automatic voltage regulator is arranged at one of a plurality of nodes from the distribution substation to the end of the three-phase distribution line. Then, voltage unbalance suppression simulation of the three-phase distribution line is performed.

As a desirable aspect, the voltage unbalance suppression support device performs the voltage unbalance suppression simulation of the three-phase distribution line assuming that the thyristor type automatic voltage regulator is arranged in one of the plurality of nodes. Perform for all of multiple nodes.

As a desirable aspect, the voltage unbalance suppression support device outputs a voltage unbalance suppression simulation result of the three-phase distribution line performed for all of the plurality of nodes.

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 realizing a voltage unbalance suppression simulation of a three-phase distribution line using a VY connection TVR.

FIG. 1 is a diagram showing an example of a three-phase distribution system to which the voltage unbalance suppression support method according to the present embodiment is applied. FIG. 2 is a diagram showing an example of loads connected to a three-phase distribution line. FIG. 3 is a diagram showing an example of horizontal mounting columns. FIG. 4 is a diagram showing an example of vertical mounting. FIG. 5 is a diagram showing an example of two-line mounting (multi-line mounting). FIG. 6 is a voltage vector diagram showing an example of voltage imbalance occurring in a three-phase distribution line. FIG. 7 is a voltage vector diagram showing an example of voltage imbalance occurring in a three-phase distribution line. FIG. 8 is a diagram in which a single-phase distribution line is modeled by a ladder circuit in order to explain the concept of the FBS method. FIG. 9 is a flowchart showing an example of power flow calculation processing using the FBS method. FIG. 10 is a schematic diagram showing an example of a TVR applied in the voltage imbalance suppression support method according to the embodiment. FIG. 11 is a voltage vector diagram showing an example of inter-phase voltages before and after TVR adjustment. FIG. 12 is a diagram illustrating an example of functional blocks of the voltage imbalance suppression support device according to the embodiment. FIG. 13 is a flowchart illustrating an example of voltage imbalance suppression support processing in the voltage imbalance suppression support method according to the embodiment. FIG. 14 is a diagram illustrating an example of simulation results of voltage imbalance suppression. FIG. 15 is a diagram illustrating an example of simulation results of voltage imbalance suppression. FIG. 16 is a diagram illustrating an example of simulation results of voltage imbalance suppression.

Hereinafter, the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited by the following modes for carrying out the invention (hereinafter referred to as embodiments). In addition, components in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those that fall within a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be combined as appropriate.

FIG. 1 is a diagram showing an example of a three-phase distribution system to which the voltage unbalance suppression support method according to the present embodiment is applied. In a three-phase distribution system 100, three-phase power is sent to a three-phase distribution line 101 from a distribution transformer 200 installed in a distribution substation. The three-phase distribution line 101 is divided into a plurality of sections (six sections in FIG. 1) at predetermined intervals X (for example, 1 km). In FIG. 1, the boundaries of each section of the three-phase distribution line 101 are nodes ND1, ND2, ND3, ND4, and ND5, respectively, and the end of the three-phase distribution line 101 is a node ND6. Hereinafter, the nodes ND1, ND2, ND3, ND4, ND5, and ND6 will be referred to as nodes ND unless otherwise distinguished. Note that the interval X between adjacent nodes ND may not necessarily be equal.

The distribution transformer 200 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 distribution transformer 200 has a transformation ratio set such that, for example, a voltage of 66 [kV] is transformed into a voltage of 6600 [V].

The three-phase distribution line 101 is a power line for supplying power from the distribution transformer 200 to the load 2 connected to each section, and is mounted on, for example, utility poles (not shown) arranged at predetermined intervals. there is Each load 2 connected to each section includes one or more single-phase loads. In the example shown in FIG. 1, it is assumed that three-phase power is supplied from the left end side of the three-phase distribution line 101 . Hereinafter, the left end side of the three-phase distribution line 101 is also referred to as the "upstream side", and the right end side of the three-phase distribution line 101 is also referred to as the "downstream side".

Each section of the three-phase distribution line 101 is, for example, a vertical column section in which three-phase distribution lines of a-phase, b-phase, and c-phase are arranged vertically, or a section in which three-phase distribution lines are arranged horizontally. This is a section with horizontal pillars.

FIG. 2 is a diagram showing an example of loads connected to a three-phase distribution line. Three-phase AC power having the same line voltage amplitude and a 120° phase difference between the line voltages is supplied from the distribution transformer 200 to the three-phase distribution lines a, b, and c that constitute the three-phase distribution line 101 . supplied.

The pole transformer 21 is, for example, a transformer 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 pole transformer 21 has a transformation ratio set so that, for example, a voltage of 6600 [V] is transformed into a voltage of 100 [V] or 200 [V]. The primary side of the pole transformer 21 is connected to any two of three-phase distribution lines a, b, and c (that is, any two phases of a-phase, b-phase, and c-phase). . FIG. 2 shows an example in which the primary side of the pole transformer 21 is connected to a distribution line a (phase a) and a distribution line b (phase b).

A load 22 is a power load provided in the three-phase distribution system 100 . A load 22 is connected to the three-phase distribution line 101 via a pole transformer 21 . The load 22 is a power load that operates by being supplied with power transformed by the pole transformer 21 . The load 22 is connected via a pole-mounted transformer 21 to any two phases of, for example, two phases of a phase and b phase, two phases of b phase and c phase, and two phases of c phase and a phase. is supplied with power.

A three-phase power load connected to the three-phase distribution system 100, which is different from the load 2 described above, is omitted for convenience of explanation. The three-phase power load is connected to all three-phase distribution lines a, b, and c of the three-phase distribution line 101, and operates by being supplied with all three-phase power of phases a, b, and c. load.

FIG. 3 is a diagram showing an example of horizontal mounting columns. In horizontal pole mounting, as shown in FIG. 3, each of the a-phase, b-phase, and c-phase distribution lines of the three-phase distribution line 101 is arranged horizontally with respect to the ground and mounted.

FIG. 4 is a diagram showing an example of vertical mounting. In the vertical mounting, as shown in FIG. 3, the a-phase, b-phase, and c-phase distribution lines of the three-phase distribution line 101 are arranged vertically to the ground and mounted.

FIG. 5 is a diagram showing an example of two-line mounting (multi-line mounting). In the two-circuit pole arrangement (multi-line pole arrangement), a plurality of three-phase distribution lines 101 are laid in parallel, and each of the a-phase, b-phase, and c-phase distribution lines of the three-phase distribution lines 101 is arranged horizontally or vertically. be done.

Next, voltage unbalance in the three-phase distribution system 100 will be described. In the three-phase power distribution system 100, there are two causes of voltage imbalance: the asymmetry of the phase arrangement and the imbalance of the load distribution. Here, the “phase arrangement” refers to the positional relationship among the distribution lines a, b, and c of the three-phase distribution line 101, and the “voltage imbalance due to the asymmetry of the phase arrangement” refers to horizontal or vertical column arrangement. , the distribution lines a, b, and c are arranged in a row, and in a two-circuit pole arrangement (multi-line pole arrangement), the mutual impedance between the lines is asymmetric due to the influence of the distribution lines of other lines. shall refer to the voltage imbalance caused by In addition, "load distribution" refers to the distribution of load capacity for each connected phase, and "voltage imbalance due to imbalance in load distribution" means that the total capacity of single-phase loads connected to each connection phase is unbalanced. shall refer to the voltage imbalance caused by balancing. In the following description, both voltage imbalance due to phase arrangement asymmetry and voltage imbalance due to load distribution imbalance are simply referred to as "voltage imbalance" without distinguishing between them.

Here, first, voltage unbalance occurring in the three-phase distribution line 101 will be described with reference to FIGS. 6 and 7. FIG. 6 and 7 are voltage vector diagrams showing an example of voltage imbalance occurring in a three-phase distribution line. FIG. 6 shows phase voltages of distribution lines a, b, and c. FIG. 7 shows phase-to-phase voltages of distribution lines a, b, and c.

6 and 7, the horizontal axis indicates the real number axis Re, and the vertical axis indicates the imaginary number axis Im. Here, the symmetric coordinate method will be used for explanation. The positive phase voltage of the three-phase distribution line 101 can be expressed by the following equation (2) using the a-phase, b-phase, and c-phase voltage vectors and the vector operator shown in the following equation (1). Also, the negative-phase voltage of the three-phase distribution line 101 can be expressed by the following equation (3) using the a-phase, b-phase, and c-phase voltage vectors and the vector operator shown in the following equation (1).

The voltage unbalance factor ε of the three-phase distribution line 101 can be represented by the ratio between the positive-sequence voltage and the negative-sequence voltage of the three-phase distribution line 101, as shown in Equation (4) below.

Also, the voltage unbalance factor ε of the three-phase distribution line 101 can be expressed by the following formulas (5) to (8) using the phase-to-phase voltages of the distribution lines a, b, and c.

In the present disclosure, for example, in the three-phase distribution system 100 shown in FIG. Also referred to as "TVR"), a FBS (Forward / Backward Sweep) method (or BSF (Backward / Forward Sweep) method, which is one of the power flow calculation methods in the power system, "FBS method" in the present disclosure) ) is used to perform a voltage imbalance suppression simulation of the three-phase distribution system 100 . Here, first, in order to facilitate the explanation, the concept of the FBS method will be explained by taking a single-phase distribution line as an example.

FIG. 8 is a diagram in which a single-phase distribution line is modeled by a ladder circuit in order to explain the concept of the FBS method. FIG. 9 is a flowchart showing an example of power flow calculation processing using the FBS method.

In FIG. 8, node ND ₁ indicates the delivery point of a distribution substation. Assume that the transmission voltage _Vs of the distribution substation at the node _ND1 is 6600 [V]. Also, in FIG. 8, a node _NDN indicates the end of the single-phase distribution line. Zn _,n+1 denotes the known node-to-node impedance of a single-phase distribution line. _Sn indicates a known load ( _Pn [kW], _Qn [kVar]) connected to the single-phase distribution line.

In FIG. 8, the load current I _n and voltage V _n at an arbitrary node ND _n and the current I _n-1,n at nodes ND _n-1,n are expressed by the following equations (9), (10), and ( 11) Represented by the formula.

In the FBS method, first, the voltage (=V _{n +1 ) at an arbitrary node ND n+1} is initialized as a target voltage of 6600 [V] (step S11), and the node ND _n is set to the above equation (9), (10) Equation (11) is executed (step S12).

Thereafter, the above equations (9), (10) and (11) are repeatedly executed up to the node _ND2 . Specifically, after step S12, n is decremented (step S13), and it is determined whether or not n has become 2 (step S14).

If n is greater than 2 (step S14; No), the process returns to step S12 and repeats the processes up to step S14.

When n becomes 2 (step S14; Yes), the following equation (12) is subsequently executed up to the node ND _N using the current I _n−1,n calculated in the above equation (10) (step S15). .

Thereafter, the above equation (12) is repeatedly executed up to the node _NDN . Specifically, after step S15, n is incremented (step S16), and it is determined whether or not n has reached N+1 (step S17).

If n is equal to or less than N (step S17; No), the process returns to step S15 and repeats the processes up to step S17.

When n reaches N+1 (step S17 _; Yes), the _difference |V _s −V _{1 | is less} than or equal to a predetermined value α (step S19).

If the difference |V _s −V ₁ | is greater than the predetermined value α (step S19; No), the process returns to step S12 and repeats the processes up to step S19.

When the difference |V _s −V ₁ | becomes equal to or less than the predetermined value α (step S19; Yes), the power flow calculation process is terminated.

By the power flow calculation process described above, the voltage simulation of the single-phase distribution line shown in FIG. 8 can be performed. Although the single-phase distribution line has been exemplified and explained here, the voltage simulation can be performed with the same concept in the three-phase distribution system 100 as well.

In the present disclosure, for example, in the three-phase distribution system 100 shown in FIG. A voltage unbalance suppression simulation of the three-phase distribution system 100 is performed. Here, an outline of a TVR (thyristor type automatic voltage regulator) applied to the three-phase distribution system 100 will be described with reference to FIG.

FIG. 10 is a schematic diagram showing an example of a TVR applied in the voltage imbalance suppression support method according to the embodiment. As shown in FIG. 10, this embodiment targets a TVR 3 with a so-called VY connection in which the upstream side is Y-connected and the downstream side is V-connected.

The TVR 3 includes Y-connected series transformers 31A, 31B, and 31C that connect secondary windings in series to each phase of the three-phase distribution system 100, and V-connected voltage transformers that are connected in parallel between the phases of the three-phase distribution system 100. regulating transformers 32ab, 32bc; and a thyristor tap changer 33 connected to the secondary windings of the voltage regulating transformers 32ab, 32bc and the primary windings of the series transformers 31A, 31B, 31C. there is

The thyristor tap changer 33 includes a plurality of thyristors (not shown). When the voltage of the distribution line fluctuates due to load fluctuation, the thyristor tap changer 33 performs tap switching of each thyristor so as to reduce the difference between the primary voltage of the distribution line and the reference voltage.

In the TVR 3 shown in FIG. 10, the thyristor tap changer 33 individually controls the ab-phase interphase voltage and the bc-phase interphase voltage. As a result, voltage unbalance in the three-phase distribution system 100 can be suppressed in the VY connection TVR 3 . Assuming that the inter-phase voltages are V _ab , V _bc , and V _ca , respectively, the vector calculation formula for the inter-phase voltages V _AB , V _BC , and V _CA after adjustment is given by the following equation (13).

In the above equation (13), a _Rab indicates the tap value of the voltage regulating transformer 32ab, and a _Rbc indicates the tap value of the voltage regulating transformer 32bc.

Here, in the voltage simulation described above, power flow calculation processing is performed using the ground voltage, that is, each phase voltage. The voltages V _ab , V _bc , and V _ca between the phases are expressed by the following equation (14) using the reference voltages E _a , E _b , and E _c as the target voltage (eg, 6600 [V]) of each phase. be done.

Further, each phase voltage E _A ', E _B ', E _C ' after adjustment is represented by the following equation (15).

The following equation (16) is derived from the above equations (14) and (15).

Further, the VY-connected TVR 3 shown in FIG. 10 has the feature that the zero-phase voltage does not change before and after the adjustment. Information on the neutral point is lost in the above equation (16). Therefore, it is necessary to set the zero-phase voltage to "0" and add a correction term to the above equation (16) so that the neutral point voltage does not change. FIG. 11 is a voltage vector diagram showing an example of inter-phase voltages before and after TVR adjustment.

The zero-phase voltage of the three-phase distribution line 101 is expressed by the following equation (17) using the symmetric coordinate method described with reference to FIGS. 6 and 7.

Therefore, the vector arithmetic expression for each phase voltage E _A , E _B , and E _C after adjustment is the following (18 ).

On the other hand, the vector calculation formula of each phase current I _A ', I _B ', I _C ' after adjustment is shown by the following formula (19).

Similarly, in the above equation (19), the neutral point information is lost. Therefore, it is necessary to add a correction term to the above equation (19) so that the zero-phase current is "0" and the neutral point voltage does not change. Therefore, the vector calculation formula for each phase current I _A , I _B , and I _C after adjustment is the following formula (20), which is obtained by adding a correction term for the zero-phase current to the above formula (19).

Here, voltage unbalance suppression of the three-phase distribution system 100 assuming that the TVR 3 shown in FIG. A specific example of the support process will be described.

FIG. 12 is a diagram illustrating an example of functional blocks of the voltage imbalance suppression support device according to the embodiment. As shown in FIG. 12, 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 connection phase determination unit 15, and a control unit 16. .

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 unbalance suppression support device 1 .

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

The storage unit 14 is, for example, a ROM (Read Only Memory), a hard disk drive, a flash memory, or a combination thereof.

The storage unit 14 stores, for example, a program for operating the voltage imbalance suppression support device 1 . The storage unit 14 further stores, for example, a program for performing voltage imbalance suppression support processing (hereinafter also referred to as "voltage imbalance suppression support processing program").

In addition, various information about the three-phase distribution system 100 is stored in advance in the storage unit 14 . Various types of information about the three-phase distribution system 100 include, for example, known inter-node impedances of the three-phase distribution line 101, known loads connected to the three-phase distribution line 101, and the like. The storage unit 14 also has a function of storing various data calculated in the voltage imbalance suppression support process.

The processing unit 15 performs a voltage imbalance suppression support process based on various types of information about the three-phase distribution system 100 stored in the storage unit 14 .

The control unit 16 controls the operation of the voltage unbalance suppression support device 1 based on, for example, a program for operating the voltage unbalance suppression support device 1 stored in the storage unit 14 . In addition, the processing unit 15 executes the voltage imbalance suppression support processing when the control unit 16 activates the voltage imbalance suppression support processing program.

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

FIG. 13 is a flowchart illustrating an example of voltage imbalance suppression support processing in the voltage imbalance suppression support method according to the embodiment.

When the voltage imbalance suppression support processing program is activated by the operator of the voltage unbalance suppression support device 1, the processing unit 15 reads various information about the three-phase distribution system 100 stored in the storage unit 14, and displays the information in FIG. The voltage unbalance suppression support process shown in is executed.

The processing unit 15 performs a voltage imbalance suppression simulation assuming that the TVR 3 is arranged at an arbitrary node NDn (for example, node ND1) of the three-phase distribution system 100 . Specifically, assuming that the TVR 3 is arranged at the node NDn, the processing unit 15 sets the target voltage of each phase (each phase reference voltage E _a , E _b , E _c ) at the node NDn to, for example, 6600 [V ] (step S1). Then, the processing unit 15 calculates the adjusted phase voltages E _A , E _B , and E _C using the above-described equations (16) and (17), and also calculates the above-described equations (19) and (20). ), the adjusted phase currents I _A , I _B , and I _C are calculated (step S2). The processing of steps S1 and S2 corresponds to the initial setting (step S11) of the power flow calculation processing shown in FIG.

The processing unit 15 uses the phase voltages E _A , E _B , E _C and the phase currents I _A , I _B , I _C calculated in step S2 to perform power flow calculation processing (see FIG. 9) for each phase. Execute (step S3).

Data calculated in the power flow calculation process is appropriately stored in the storage unit 14 . Then, based on the data stored in the storage unit 14, the processing unit 15 calculates the voltage unbalance rate εx for each node NDx using the above formulas (1) to (8) (voltage unbalance rate rate calculation process), and stored in the storage unit 14 (step S4).

The processing unit 15 determines whether or not the voltage unbalance suppression simulation (power flow calculation processing (step S3) and voltage unbalance rate calculation processing (step S4)) on the assumption that the TVRs 3 are arranged at all the nodes NDx has been completed. Determine (step S5). If the voltage imbalance suppression simulation assuming that the TVR3 is placed at all the nodes NDx has not been completed (step S5; No), the process returns to step S1, and the voltage The processing from step S1 to step S5 is repeatedly executed until the imbalance suppression simulation is completed.

When the voltage imbalance suppression simulation assuming that TVRs 3 are arranged at all nodes NDx is completed (step S5; Yes), the processing unit 15 retrieves data from various data stored in each node storage unit 14, for example, as shown in FIG. The charts shown in FIGS. 15 and 16 are generated, and output processing such as displaying them on the display unit 13 or outputting them from the output unit 12 is performed as the result of the voltage imbalance suppression simulation (step S6). End the unbalance suppression support process.

14, 15, and 16 are diagrams showing an example of voltage unbalance suppression simulation results.

14 and 15, the horizontal axis indicates the relative distance of each node ND to the distribution substation of the three-phase distribution system 100 shown in FIG. 1, and the vertical axis indicates the line voltage. FIG. 14 shows simulation results of the line voltage when it is assumed that the TVR3 is arranged at the node ND2 of the three-phase distribution system 100 shown in FIG. FIG. 15 shows simulation results of the line voltage when the TVR 3 is not arranged at any node ND of the three-phase distribution system 100 shown in FIG. 14 and 15, the solid line indicates the line voltage _Vbc , the dashed line indicates the line voltage _Vca , and the dashed line indicates the line voltage _Vab .

In FIG. 16, the horizontal axis indicates the relative distance of each node ND to the distribution substation of the three-phase distribution system 100 shown in FIG. 1, and the vertical axis indicates the voltage unbalance rate. In FIG. 16, the solid line indicates the simulation result of the voltage unbalance rate when it is assumed that the TVR 3 is arranged at the node ND2 of the three-phase distribution system 100 shown in FIG. The dashed line indicates the simulation result of the voltage unbalance rate when the TVR3 is not arranged also at the node ND of .

As shown in FIGS. 14 and 16, voltage imbalance is suppressed at the node ND2 on which the TVR3 is supposed to be placed. As a result, as shown in FIG. 16, the voltage unbalance rate of the node ND6 at which the voltage unbalance rate reaches the maximum value when the TVR 3 is not arranged at any node ND of the three-phase distribution system 100 ( In the example shown, it is approximately 1.4 [%]), and the voltage unbalance rate of the node ND2 at which the voltage unbalance rate reaches the maximum value when it is assumed that the TVR3 is arranged at the node ND2 is 1/2 or less (Fig. 16 In the example shown in , it can be seen that it is approximately 0.7 [%] or less).

Further, as shown in FIGS. 14 and 15, line voltages V _ab , Line voltages V _ab , V _bc , V bc at the terminal (here, node ND6) of the three-phase distribution line 101 when the TVR 3 is not arranged at any node ND of the three-phase distribution system 100 due to variations in V _bc and V _ca It can be seen that the variation is smaller than the variation of _Vca . As a result, for example, it is possible to increase the control margin width with respect to the voltage control value (from 95 [V] to 105 [V]) when converted to 100 [V].

In the above example, in order to simplify the chart, FIG. FIG. 15 shows the simulation result of the line voltage when the TVR 3 is not placed in the three-phase distribution system 100 shown in FIG. and the simulation result of the line-to-line voltage when the TVR 3 is not arranged at any node ND shown in FIG. can be This facilitates comparison between the presence or absence of the TVR 3 . 14, 15, and 16 may be superimposed and displayed, or may be output from the output unit 12. FIG. Thereby, the visibility of the simulation result can be improved.

Here, FIG. 14 illustrates a chart showing the simulation result of the line voltage when it is assumed that the TVR 3 is arranged at the node ND2 of the three-phase distribution system 100 shown in FIG. In the suppression support process, the processing unit 15 generates, for example, charts shown in FIGS. or perform output processing such as output from the output unit 12 . This makes it possible to examine the location (node ND) where the TVR 3 is arranged in the actual three-phase distribution system 100 .

Also, the form of the chart generated as the voltage unbalance suppression simulation result is not limited to the forms shown in FIGS. For example, it may include more data than calculated in the power flow calculation process. It is also possible to generate a chart that can determine whether or not has cleared the threshold.

As described above, the voltage unbalance suppression support method according to the present embodiment uses the power flow calculation method to perform a voltage unbalance suppression simulation of the three-phase distribution line 101 according to the arrangement position of the TVR 3 in the VY connection. At this time, the target voltage E _a of the a-phase voltage to ground of the TVR 3, the target voltage E b of the b-phase voltage to _{ground, the target voltage E c of} the c-phase voltage to ground, the adjusted a-phase voltage to ground E _A , and the adjusted Later b-phase voltage to ground E _B , adjusted c-phase voltage to ground E _C , tap value a _Rab of voltage regulating transformer 32ab connected in parallel between a-phase and b-phase, b-phase and c-phase Using the tap value a _Rbc of the voltage regulating transformer 32bc connected in parallel between and, a voltage simulation is performed with a correction term added to prevent the neutral point voltage from changing.

As a result, it is possible to realize voltage imbalance suppression simulation of the three-phase distribution line 101 using the VY connection TVR 3 .

Further, the voltage imbalance suppression support method according to the present embodiment assumes that the TVR 3 is arranged at one node NDn among the plurality of nodes NDx from the distribution substation to the end of the three-phase distribution line 101. A voltage imbalance suppression simulation of the three-phase distribution line 101 is performed.

More specifically, voltage imbalance suppression simulation of the three-phase distribution line 101 assuming that the TVR 3 is arranged at one of the plurality of nodes NDx is performed for all of the plurality of nodes NDx.

In addition, the voltage unbalance suppression support device 1 according to the present embodiment uses the power flow calculation method to perform a voltage unbalance suppression simulation of the three-phase distribution line 101 according to the arrangement position of the VY connection TVR 3, Target voltage _E a of a-phase voltage to ground of TVR 3 , target voltage E _b of b-phase voltage to ground, target voltage E _c of c-phase voltage to ground, adjusted a-phase voltage to ground E _A , adjusted b phase voltage to ground E _B , adjusted c-phase voltage to ground E _C , tap value a _Rab of voltage regulating transformer 32ab connected in parallel between phases a and b, and between phases b and c Using the tap value a _Rbc of the voltage regulating transformer 32bc connected in parallel to , a voltage simulation is performed with a correction term added so that the neutral point voltage does not change.

As a result, it is possible to realize voltage imbalance suppression simulation of the three-phase distribution line 101 using the VY connection TVR 3 .

Further, the voltage imbalance suppression support device 1 according to the present embodiment assumes that the TVR 3 is arranged at one node NDn among a plurality of nodes NDx from the distribution substation to the end of the three-phase distribution line 101. , voltage imbalance suppression simulation of the three-phase distribution line 101 is performed.

More specifically, voltage imbalance suppression simulation of the three-phase distribution line 101 assuming that the TVR 3 is arranged at one of the plurality of nodes NDx is performed for all of the plurality of nodes NDx.

Then, the voltage unbalance suppression support device 1 outputs the results of the voltage unbalance suppression simulation of the three-phase distribution line 101 performed for all of the plurality of nodes NDx.

This makes it possible to examine the location (node ND) where the TVR 3 is arranged in the actual three-phase distribution system 100 .

1 voltage imbalance suppression support device 2 load 3 TVR (thyristor type automatic voltage regulator)
11 Input unit 12 Output unit 13 Display unit 14 Storage unit 15 Connection phase determination unit 16 Control unit 21 Pole transformer 22 Loads 31A, 31B, 31C Series transformers 32ab, 32bc Voltage adjustment transformer 33 Thyristor tap changer 100 Phase distribution system 101 Three-phase distribution line 200 Distribution transformer

Claims (7)

A voltage unbalance suppression support method for performing a voltage unbalance suppression simulation of a three-phase distribution line according to the arrangement position of a thyristor type automatic voltage regulator using a power flow calculation method,
The thyristor type automatic voltage regulator is
a Y-connected series transformer in which secondary windings are connected in series to each of the first phase, the second phase, and the third phase;
V-connected voltage regulating transformers connected in parallel between the first phase and the second phase and between the second phase and the third phase, respectively;
a thyristor tap changer connected to the secondary winding of the voltage regulating transformer and the primary winding of the series transformer;
with
E a is the target voltage of the first phase voltage to ground, E _b is the target voltage of the second phase voltage to ground, E _c is the target voltage of the third phase voltage to ground, _and E is the adjusted first phase voltage to ground _A , _EB the regulated second phase voltage to ground, E _C the regulated third phase voltage to ground, and the tap value of the voltage regulating transformer connected in parallel between the first and second phases. is a _Rab and the tap value of the voltage regulating transformer connected in parallel between the second and third phases is a _Rbc , the three Conduct voltage imbalance suppression simulations for phase distribution lines,
Voltage imbalance suppression support method.

Assuming that the thyristor type automatic voltage regulator is arranged at one node among a plurality of nodes from the distribution substation to the end of the three-phase distribution line, a voltage imbalance suppression simulation of the three-phase distribution line is performed. conduct,
The voltage imbalance suppression support method according to claim 1 . Performing a voltage unbalance suppression simulation of the three-phase distribution line on the assumption that the thyristor-type automatic voltage regulator is arranged at one of the plurality of nodes for all of the plurality of nodes;
3. The voltage imbalance suppression support method according to claim 2. A voltage unbalance suppression support device that performs a voltage unbalance suppression simulation of a three-phase distribution line according to the arrangement position of a thyristor type automatic voltage regulator using a power flow calculation method,
The thyristor type automatic voltage regulator is
a Y-connected series transformer in which secondary windings are connected in series to each of the first phase, the second phase, and the third phase;
V-connected voltage regulating transformers connected in parallel between the first phase and the second phase and between the second phase and the third phase, respectively;
a thyristor tap changer connected to the secondary winding of the voltage regulating transformer and the primary winding of the series transformer;
with
The voltage imbalance suppression support device includes:
E a is the target voltage of the first phase voltage to ground, E _b is the target voltage of the second phase voltage to ground, E _c is the target voltage of the third phase voltage to ground, _and E is the adjusted first phase voltage to ground _A , the regulated second phase voltage to ground _EB , the regulated third phase voltage to ground E _C , the tap value of the voltage regulating transformer connected in parallel between the first and second phases is a _Rab and the tap value of the voltage regulating transformer connected in parallel between the second and third phases is a _Rbc , the three Conduct voltage imbalance suppression simulations for phase distribution lines,
Voltage unbalance suppression support device.

The voltage imbalance suppression support device includes:
Assuming that the thyristor type automatic voltage regulator is arranged at one node among a plurality of nodes from the distribution substation to the end of the three-phase distribution line, a voltage imbalance suppression simulation of the three-phase distribution line is performed. conduct,
The voltage unbalance suppression support device according to claim 4. The voltage imbalance suppression support device includes:
Performing a voltage unbalance suppression simulation of the three-phase distribution line on the assumption that the thyristor-type automatic voltage regulator is arranged at one of the plurality of nodes for all of the plurality of nodes;
The voltage unbalance suppression support device according to claim 5. The voltage imbalance suppression support device includes:
outputting a simulation result of voltage unbalance suppression of the three-phase distribution line performed for all of the plurality of nodes;
The voltage unbalance suppression support device according to claim 6.

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