JP6967440B2 - Voltage control device, voltage control method, voltage control program and evaluation device - Google Patents

Description

The present invention relates to a voltage control device, a voltage control method, a voltage control program and an evaluation device.

In recent years, the introduction of large-capacity loads such as heat pump water heaters and photovoltaic power generation (PV: Photovoltaics) systems has become widespread. Due to the introduction of large-capacity loads, fluctuations in household loads are increasing. In addition, when a photovoltaic power generation system is introduced, the occurrence of reverse power flow to the distribution system is increasing.

The voltage of the high-voltage distribution line constantly fluctuates as the household load fluctuates. When the supply from the three-phase high-voltage distribution line to the single-phase load is biased due to the voltage fluctuation of the high-voltage wiring, the voltage between the distribution lines becomes unbalanced and the three-phase AC voltage imbalance occurs in the distribution system. do. In addition, when reverse power flow occurs due to a photovoltaic power generation system or the like, a voltage imbalance of three-phase alternating current occurs in the distribution system.

For this reason, the occurrence of voltage imbalance in the three-phase alternating current is increasing with the increase in the introduction of the large-capacity load and the photovoltaic power generation system described above. As a countermeasure against the voltage imbalance of three-phase alternating current in this distribution system, SVR (Step Voltage Regulator) or the like is generally used. The SVR is a device that optimizes the voltage of the distribution system. The SVR aims to optimize the voltage by switching taps in a batch of three phases.

However, the SVR has a problem that it cannot follow fast output fluctuations such as solar power generation. Further, in the voltage adjustment by adjusting the reactive power, there is a limit to the voltage adjustment due to a large voltage fluctuation, or the device is large and expensive. Therefore, as a voltage control device that can achieve both high-speed control performance and low cost, HVR (Hybrid Voltage Regulator) that performs voltage control independently in three phases is available as a device that can control high speed and realize low cost compared to SVR. Proposed.

As a control technique for voltage imbalance of such three-phase alternating current, there is a conventional technique for performing stepless voltage adjustment for each of the three phases. Further, there is a conventional technique for centrally managing the input of a phase-advancing capacitor to the distribution system and the voltage adjustment by SVR in order to reduce the voltage difference between the three phases. Further, there is a conventional technique for eliminating the voltage imbalance of three-phase alternating current by switching taps in each phase.

Japanese Unexamined Patent Publication No. 2014-176270 Japanese Unexamined Patent Publication No. 2013-132988 Japanese Unexamined Patent Publication No. 2015-21480

However, even if HVR is simply introduced, it is difficult to appropriately determine the control amount that minimizes the voltage imbalance. Further, in the technique for performing stepless voltage adjustment, a specific method for eliminating the voltage imbalance has not been studied, and it is difficult to obtain an appropriate control amount. Further, in the conventional technique of centrally managing the input of the phase-advancing capacitor and the voltage adjustment by the SVR, the processing is complicated and it is difficult to suppress the cost increase because the control of the entire system is performed. Further, in the conventional technique of eliminating the imbalance by switching taps in each phase, voltage deviation is not controlled and appropriate control including the voltage value is difficult.

The technique disclosed is made in view of the above, and an object thereof is to provide a voltage control device, a voltage control method, a voltage control program, and an evaluation device for improving the efficiency of voltage control of a distribution system by HVR. ..

In one embodiment of the voltage control device, voltage control method, voltage control program and evaluation device disclosed in the present application, the voltage control device is arranged on a distribution system that transmits three-phase AC power. The generation unit generates a combination of control amounts for the voltage of each phase by using a plurality of predetermined control amounts for the voltage of each phase of the distribution system. The voltage acquisition unit acquires the voltage of each phase at a predetermined point on the distribution system when the voltage is controlled using each control amount for each combination of the control quantities generated by the generation unit. The extraction unit extracts a candidate combination from the combination of the control amounts based on the voltage of each phase acquired by the voltage acquisition unit. The specific unit specifies a combination of control amounts that minimizes the voltage imbalance rate of the controlled voltage of each phase at the predetermined point from the candidate combinations extracted by the extraction unit. The control unit controls the voltage of each phase by using the combination of the control amounts specified by the specific unit.

In one aspect, the present invention can improve the efficiency of control of the distribution system by HVR.

FIG. 1 is a schematic configuration diagram of a distribution system. FIG. 2 is a diagram showing details of the arrangement state of the HVR. FIG. 3 is a block diagram of the HVR according to the first embodiment. FIG. 4 is a flowchart of the control amount determination process. FIG. 5 is a diagram showing control results when the HVR according to the embodiment is used and when the conventional HVR is used. FIG. 6 is a block diagram of the evaluation device according to the second embodiment. FIG. 7 is a diagram showing the maximum voltage unbalance rate for each arrangement position. FIG. 8 is a diagram showing the number of tap changes for each arrangement position.

Hereinafter, examples of the voltage control device, the voltage control method, the voltage control program, and the evaluation device disclosed in the present application will be described in detail with reference to the drawings. The following examples do not limit the voltage control device, voltage control method, voltage control program, and evaluation device disclosed in the present application.

FIG. 1 is a schematic configuration diagram of a distribution system. As shown in FIG. 1, the distribution system 2 according to the present embodiment has a plurality of nodes 4 that are branched from the main line and to which consumers are connected. Consumers at Node 4 are houses, factories, and the like. A large-capacity load, a solar power generation system, or the like may be arranged in the consumer.

The distribution substation 3 is connected to the distribution system 2. The distribution substation 3 adjusts the electric power transmitted from the power plant to a predetermined voltage and transmits the electric power to the distribution system 2.

SVRs 51 to 55 are arranged on the distribution system 2 in a state where the HVR1 which is a voltage control device for independently performing voltage control in three phases is not arranged. The SVRs 51 to 55 are voltage control devices that perform voltage control even during reverse power transmission in the same manner as during forward power transmission, and the control range of voltage control is small and flexible control is possible.

Hereinafter, a case will be described in which voltage control of three-phase alternating current is performed by exchanging HVR1 with any one of SVRs 51 to 55. For example, FIG. 1 shows a case where SVR52 is replaced with HVR1.

FIG. 2 is a diagram showing details of the arrangement state of the HVR. As shown in FIG. 2, the distribution system 2 has power transmission paths 201 to 203 as a main line. In the following, each phase of the three-phase alternating current may be referred to as a to c phase. The case where the a-phase AC power flows through the power transmission path 201, the b-phase AC power flows through the power transmission path 202, and the c-phase AC power flows through the power transmission path 203 will be described. As shown in FIG. 1, other SVRs 51 to 55 are also arranged in the distribution system 2, but in the description here, the control by the HVR 1 in the distribution system 2 will be focused on.

The HVR 1 is connected to each of the three transmission paths 201 to 203 of the main line of the distribution system 2. Then, the HVR 1 receives power input from each of the transmission paths 201 to 203, and controls the voltage in each phase to be an appropriate voltage and the unbalance rate to be within the unbalance rate specified value. Then, the HVR 1 transmits the electric power of each phase whose voltage is controlled by using the transmission paths 201 to 203.

The electric power transmitted from the HVR 1 is sent to each node 4. Each node 4 has a transformer 41 and a consumer 43. Further, the transformer 41 and the consumer 43 are connected by a transmission line 42. The transformer 41 acquires AC power from two different transmission paths among the transmission paths 2001 to 203. For example, the transformer 41 acquires the b-phase AC power flowing through the power transmission path 202 and the c-phase AC power flowing through the power transmission path 203. Then, the transformer 41 supplies the electric power having the line voltage, which is the voltage difference of the acquired two-phase AC power, to the consumer 43 via the transmission line 42.

It is stipulated that the consumer 43 supplies electric power having a voltage within 95 to 107 V to a load of an electric appliance or the like. Therefore, the electric power transmitted from the transformer 41 to the consumer 43 via the transmission line 42 is within a predetermined appropriate range so that the electric power supplied to the load by the consumer 43 is within 95 to 107V. It is preferable to be adjusted. For example, the appropriate range can be determined to be 102 to 107V. Therefore, HVR1 is adjusted so that the line voltage is within an appropriate range. This HVR1 corresponds to an example of a "voltage control device". The voltage control by HVR1 will be described in detail below.

FIG. 3 is a block diagram of the HVR according to the first embodiment. As shown in FIG. 3, the HVR 1 includes a voltage control unit 10, a pre-control information acquisition unit 11, a determination unit 12, a storage unit 13, a control quantity set generation unit 14, a post-control information acquisition unit 15, and a control quantity extraction within a predetermined condition. It has a unit 16 and an optimum control amount specifying unit 17. Here, a case will be described in which the HVR 1 is replaced with any of the SVRs 51 to 55 in FIG. 1 and arranged on the distribution system 2.

The voltage control unit 10 has a voltage control mechanism including an inverter circuit, a tap changer circuit, a control transformer, and the like for each of the a to c phases. That is, the voltage control unit 10 can perform independent voltage control for each of the three phases.

The voltage control unit 10 receives the input of the three-phase AC power sent by the distribution system 2. Then, the voltage control unit 10 performs voltage control on the power of each phase of the three-phase AC power, and sends the voltage-controlled power to the distribution system 2. The voltage before voltage adjustment by the voltage control unit 10 may be referred to as a primary side voltage, and the voltage after voltage adjustment by the voltage control unit 10 may be referred to as a secondary side voltage. If the optimum control amount specifying unit 17, which will be described later, has not yet determined the combination of the control amount for the voltage of each phase, the voltage control unit 10 controls the primary side voltage using, for example, a predetermined control amount. It converts to the secondary side voltage and sends out the three-phase AC power having the converted secondary side voltage.

When the optimum control amount specifying unit 17, which will be described later, determines the combination of the control amounts for the voltage of each phase, the voltage control unit 10 receives the input of the determined control amount of each phase from the optimum control amount specifying unit 17. Then, the voltage control unit 10 controls using the control amount input to the primary side voltage, converts it into the secondary side voltage, and sends out the three-phase AC power having the converted secondary side voltage. The voltage control unit 10 corresponds to an example of a “control unit”.

The pre-control information acquisition unit 11 receives the input of the secondary side voltage of each phase of the three-phase AC power transmitted from the voltage control unit 10 to the distribution system 2. Further, the pre-control information acquisition unit 11 acquires the passing current of the HVR 1 in the distribution system 2.

Further, the pre-control information acquisition unit 11 specifies a reference point used for voltage adjustment. The reference point is an arbitrary point assumed on the distribution system 2. The pre-control information acquisition unit 11 may hold information on a plurality of points in advance and select a reference point from the holding points. For example, the pre-control information acquisition unit 11 specifies the reference point R in FIG. 2 as a reference point used for voltage adjustment. The pre-control information acquisition unit 11 has a line impedance from the HVR 1 to each point on the distribution system 2 in advance. Therefore, the pre-control information acquisition unit 11 acquires a predetermined line impedance from the HVR 1 to the reference point R.

Then, the pre-control information acquisition unit 11 obtains an estimated value of the reference point voltage of the reference point R by using the analysis method of the vector LDC (Voltage Drop Compensator) method. Specifically, the pre-control information acquisition unit 11 estimates the reference point voltage at the reference point R by performing a vector LDC calculation using the passing current, the secondary side voltage, and the line impedance. That is, the control pre-information obtaining unit 11, the secondary voltage _V a in each transmission path 201-203 as shown in FIG. _2, V b, in the case of _{V c,} the reference point R reference point voltage _V La, V _Lb V _Lc is calculated.

Further, the pre-control information acquisition unit 11 acquires the voltage control amount in each phase from the voltage control unit 10. Then, the pre-control information acquisition unit 11 obtains the unbalance rate of the voltage by using the control amount of the voltage in each phase, the reference point voltage, the line impedance, and the passing current.

Here, how to obtain the unbalance rate will be described. The following formula (1) is a formula expressing a set of control quantities in each phase. Here, h ₁ , h ₂ , and h ₃ are time-based control quantities of each phase.

The pre-control information acquisition unit 11 calculates the estimated reference point voltage of each phase by using the set of controlled quantities represented by the mathematical formula (1) in the following mathematical formula (2). Here, Z is the line impedance from HVR1 to the reference point Rm. Further, V _a , V _b , and V _c are secondary voltage. Further, V _La , _{VL b} , and _{VL c} are reference point voltages of each phase. Further, I _a , I _b , and I _c are the passing currents of the respective transmission paths 201 to 203. Also, the points above each variable represent complex numbers over time.

Next, the pre-control information acquisition unit 11 calculates the _{positive phase voltage E 1} and the _{negative phase voltage E 2 by using the following mathematical formula (3).}

Then, the pre-control information acquisition unit 11 obtains the unbalance rate ε by using the following mathematical formula (4).

After that, the pre-control information acquisition unit 11 outputs the estimated value of the reference point voltage of the reference point R and the calculated unbalance rate of the voltage to the determination unit 12. The pre-control information acquisition unit 11 corresponds to an example of the “pre-control voltage acquisition unit”.

The determination unit 12 stores in advance an unbalance rate defined value representing an allowable limit value of the voltage unbalance rate. For example, the determination unit 12 stores the unbalance rate defined value as 0.8%. Further, the determination unit 12 stores in advance an appropriate range of the line voltage of the three-phase AC power. For example, the determination unit 12 stores 102 to 107V as an appropriate range.

The determination unit 12 receives the input of the estimated value of the reference point voltage of the reference point R and the calculated unbalance rate of the voltage from the pre-control information acquisition unit 11. Next, the determination unit 12 calculates the line voltage between each phase from the estimated value of the reference point voltage of each phase at the acquired reference point R. Then, the determination unit 12 determines whether or not the line voltage is within an appropriate range. If it does not fall within the proper range, the determination unit 12 determines that the voltage control amount needs to be adjusted.

On the other hand, when the line voltage at the acquired reference point R is within an appropriate range, the determination unit 12 determines whether or not the acquired unbalance rate is smaller than the unbalance rate specified value. When the acquired unbalance rate is equal to or greater than the unbalance rate specified value, the determination unit 12 determines that the voltage control amount needs to be adjusted.

When it is determined that the voltage control amount needs to be adjusted, the determination unit 12 instructs the control amount set generation unit 14 to execute a new control amount determination process. On the other hand, when the acquired unbalance rate is smaller than the unbalance rate specified value, the determination unit 12 determines that the adjustment of the voltage control amount is unnecessary. When it is determined that the adjustment of the voltage control amount is unnecessary, the determination unit 12 ends the process of determining the new control amount.

The storage unit 13 stores a plurality of voltage control amounts in each phase in advance. For example, the storage unit 13 stores a lower limit control amount that drops the voltage of phase a to the lowest possible voltage, an unadjusted control amount that does not change the voltage, and an upper limit control amount that raises the voltage to the highest possible voltage. Further, the storage unit 13 increases the voltage of the a-phase by a predetermined value from the voltage of the unadjusted control amount and the voltage of the unadjusted control amount by a predetermined value. Each control amount that becomes each voltage is stored. The storage unit 13 also stores such a plurality of controlled quantities for the b-phase and the c-phase.

The control amount set generation unit 14 receives an instruction from the determination unit 12 to execute a new control amount determination process. Then, the control amount set generation unit 14 generates all the combinations of the control amounts of each phase stored in the storage unit 13. Then, the control quantity set generation unit 14 outputs the combination of the generated control quantities to the post-control information acquisition unit 15. This controlled variable set generation unit 14 corresponds to an example of the “generation unit”.

The post-control information acquisition unit 15 receives the input of the secondary side voltage of each phase of the three-phase AC power transmitted from the voltage control unit 10 to the distribution system 2. Further, the post-control information acquisition unit 15 acquires the passing current of the HVR 1 in the distribution system 2. Here, the post-control information acquisition unit 15 may acquire information on the secondary side voltage and the passing current used by the pre-control information acquisition unit 11.

Further, the post-control information acquisition unit 15 acquires the information of the reference point R determined by the pre-control information acquisition unit 11. Further, the post-control information acquisition unit 15 acquires the line impedance from the HVR 1 to the reference point R from the pre-control information acquisition unit 11.

Next, the post-control information acquisition unit 15 receives input of information on the combination of control quantities generated by the control quantity set generation unit 14. Then, the post-control information acquisition unit 15 selects one combination of control quantities from the combination of acquired control quantities. The combination of control quantities selected by the post-control information acquisition unit 15 is referred to as "selection control quantity".

Next, the post-control information acquisition unit 15 calculates the secondary side voltage when the voltage of each phase is controlled using the selective control amount, using the acquired secondary side voltage. For example, the post-control information acquisition unit 15 controls the voltage of each phase using the selective control amount by applying the voltage change caused by the difference between the current control amount and the selective control amount to the acquired secondary voltage. Calculate the secondary voltage in the case of. Hereinafter, the secondary side voltage when the voltage of each phase is controlled using this selective control amount is simply referred to as “secondary side voltage”.

Next, the post-control information acquisition unit 15 performed voltage control using the selective control amount using the vector LDC method analysis method based on the selective control amount, the secondary side voltage, the passing current, and the line impedance. The estimated value of the reference point voltage of the reference point R in the case is obtained. Hereinafter, the reference point voltage of the reference point R when voltage control is performed using the selective control amount is simply referred to as “reference point voltage”. That is, the post-control information obtaining unit 15, the secondary voltage Va in each transmission path 201-203 as shown in FIG. 2, Vb, in the case of Vc, the reference point R reference point voltage _{V La, V} Lb _{V Lc} Ask for. However, where the reference point voltage _{V La, V} Lb _{V Lc} is otherwise combination selection control amount for the current control amount, the reference point voltage _V La calculated by the pre-control information acquisition unit _{11, V Lb} The value is different from _VLc.

Further, the post-control information acquisition unit 15 obtains a voltage imbalance rate using a selective control amount, a reference point voltage, a line impedance, and a passing current. The post-control information acquisition unit 15 obtains the unbalance rate using mathematical formulas (1) to (4) in the same manner as the pre-control information acquisition unit 11.

The post-control information acquisition unit 15 calculates the reference point voltage and the unbalanced amount for all the combinations of the control quantities of the voltages of each phase acquired from the control quantity set generation unit 14. Then, the post-control information acquisition unit 15 outputs the reference point voltage and the unbalance rate of all the combinations of the control amounts of the voltages of each phase to the control amount extraction unit 16 within a predetermined condition. The post-control information acquisition unit 15 corresponds to an example of the “voltage acquisition unit”.

The control amount extraction unit 16 within a predetermined condition stores in advance an unbalance rate defined value representing an allowable limit value of the voltage unbalance rate. For example, the determination unit 12 stores the unbalance rate defined value as 0.8%. Further, the determination unit 12 stores in advance an appropriate range of the line voltage of the three-phase AC power. For example, the determination unit 12 stores 102 to 107V as an appropriate range.

The control amount extraction unit 16 within a predetermined condition receives the input of the reference point voltage and the unbalance rate of all the combinations of the control amounts of the voltages of each phase from the post-control information acquisition unit 15. Next, the control amount extraction unit 16 within a predetermined condition obtains the line voltage between each phase for each combination of the control amounts of the voltage of each phase. Then, the control amount extraction unit 16 within a predetermined condition sets a combination of control amounts in which the unbalance rate is smaller than the unbalance rate specified value and the line voltage is within an appropriate range for all control amounts of the voltage of each phase. Extract from the combination of. Then, the control amount extraction unit 16 within a predetermined condition outputs the combination of the voltage control amounts of the extracted phases as a candidate combination to the optimum control amount identification unit 17 together with the unbalance rate of each candidate combination. The controlled amount extraction unit 16 within a predetermined condition corresponds to an example of the “extraction unit”.

The optimum control amount specifying unit 17 receives the input of the candidate combination and the unbalance rate of each candidate combination from the control amount extraction unit 16 within a predetermined condition. Then, the optimum control amount specifying unit 17 specifies a combination of voltage control amounts of each phase having the smallest unbalance rate from the candidate combinations. Then, the optimum control amount specifying unit 17 notifies the voltage control unit 10 of the combination of the control amounts of the voltages of the specified phases. The optimum control amount specifying unit 17 corresponds to an example of the “specific unit”.

Here, in this embodiment, the HVR 1 executes the above-mentioned adjustment of the control value at predetermined intervals. For example, HVR1 adjusts the control value every 1 to 10 seconds.

Next, with reference to FIG. 4, the flow of the control amount determination process of the voltage of each phase in the three-phase AC power by HVR1 according to this embodiment will be described. FIG. 4 is a flowchart of the control amount determination process.

The pre-control information acquisition unit 11 acquires the secondary voltage and the passing current of the HVR1. Further, the pre-control information acquisition unit 11 determines the reference point R and acquires a predetermined line impedance from the HVR 1 to the determined reference point R. Further, the pre-control information acquisition unit 11 acquires the current voltage control amount of each phase from the voltage control unit 10. Then, the pre-control information acquisition unit 11 uses the vector LDC method analysis method based on the control amount of the voltage of each phase, the secondary side voltage, the passing current, and the line impedance, and uses the reference point voltage and the reference point voltage in the current state. Acquire the unbalance rate (step S1). After that, the pre-control information acquisition unit 11 outputs the reference point voltage and the unbalance rate in the current state to the determination unit 12.

The determination unit 12 receives the input of the reference point voltage and the unbalance rate in the current state from the pre-control information acquisition unit 11. Then, the determination unit 12 determines whether the unbalance rate is smaller than the unbalance rate specified value (step S2).

When the unbalance rate is smaller than the unbalance rate specified value (step S2: affirmative), the determination unit 12 determines whether or not the line voltage of the three-phase AC power is within an appropriate range (step S3). When the line voltage is within the appropriate range (step S3: affirmative), the determination unit 12 ends the process of determining the new control amount.

On the other hand, when the unbalance rate is equal to or higher than the unbalance rate specified value (step S2: negative) or the line voltage is not within the appropriate range (step S3: negative), the determination unit 12 needs to adjust the voltage control amount. Is determined. Then, the determination unit 12 instructs the control amount set generation unit 14 to execute the determination process of the new control amount. The control amount set generation unit 14 receives an instruction from the determination unit 12 to execute a new control amount determination process. Then, the control amount set generation unit 14 generates all combinations of the voltage control amounts of each phase by using the control amount of the voltage of each phase stored in the storage unit 13 (step S4). After that, the control amount set generation unit 14 outputs all the combinations of the control amounts of the voltages of each phase to the post-control information acquisition unit 15.

The post-control information acquisition unit 15 acquires the secondary voltage of each phase of the three-phase AC power transmitted from the voltage control unit 10 to the distribution system 2. Further, the post-control information acquisition unit 15 acquires the passing current of the HVR 1 in the distribution system 2. Further, the post-control information acquisition unit 15 acquires the information of the reference point R and the information of the line impedance from the HVR 1 to the reference point R from the pre-control information acquisition unit 11. Further, the post-control information acquisition unit 15 receives the input of all combinations of the control quantities of the voltages of each phase from the control quantity set generation unit 14. Then, the post-control information acquisition unit 15 selects one combination of control quantities from all combinations of control quantities of the voltage of each phase. Then, the post-control information acquisition unit 15 controls each combination by using the vector LDC method analysis method based on the selection control amount, the secondary side voltage when the selection control amount is used, the passing current, and the line impedance. The reference point voltage and the unbalance rate when the quantity is used are acquired (step S5). After that, the post-control information acquisition unit 15 outputs the reference point voltage and the unbalance rate when the control amount of each combination is used to the control amount extraction unit 16 within a predetermined condition.

The control amount extraction unit 16 within a predetermined condition receives the input of the reference point voltage and the unbalance rate when the control amount of each combination is used from the control information acquisition unit 15. Then, in the control amount extraction unit 16 within the predetermined conditions, the unbalance rate is smaller than the unbalance rate specified value and the line voltage of the three-phase AC voltage is set from all the combinations of the control amounts of the voltages of each phase. A combination of control amounts that falls within the appropriate range is extracted as a candidate combination. (Step S6). After that, the control amount extraction unit 16 within a predetermined condition outputs the extracted candidate combinations to the optimum control amount identification unit 17 together with the unbalance rate of each candidate combination.

The optimum control amount specifying unit 17 receives the input of the candidate combination from the control amount extraction unit 16 within a predetermined condition. Then, the optimum control amount specifying unit 17 specifies a combination of control amounts having the minimum unbalance rate from the candidate combinations (step S7). Then, the optimum control amount specifying unit 17 outputs the combination of the specified control amounts to the voltage control unit 10.

The voltage control unit 10 receives an input of a combination of control amounts specified by the optimum control amount specifying unit 17. Then, the voltage control unit 10 controls the voltage of the three-phase AC power in the distribution system 2 by using the acquired control amount of the combination (step S8).

Further, FIG. 5 is a diagram showing control results when the HVR according to the embodiment is used and when the conventional HVR is used. The horizontal axis of FIG. 5 represents either the conventional HVR in which the control amount is not determined using the line voltage and the unbalance rate, or the HVR1 according to the embodiment. Further, the vertical axis on the left side of FIG. 5 represents the total voltage deviation time value, which is the total time when the line voltage deviates from the appropriate range. The vertical axis on the right side of FIG. 5 represents the maximum value of the unbalance rate. Here, the control result when the HVR1 is arranged at the position of the SVR52 having the best control result is taken as the control result of the HVR1 according to the first embodiment.

The maximum unbalance rate of the conventional HVR is represented by point 301. On the other hand, the maximum unbalance rate of HVR1 according to the embodiment is represented by a point 302. In this case, by using HVR1 according to Example 1, the maximum unbalance rate was improved by 39.7% as compared with the conventional HVR.

Further, the total value of the voltage deviation time of the conventional HVR is represented by the point 311. On the other hand, the total voltage deviation time value of HVR1 according to the embodiment is represented by a point 312. In this case, by using the HVR1 according to the first embodiment, the total voltage deviation time is improved by 62.3% as compared with the conventional HVR.

In this way, by arranging the HVR 1 according to the embodiment at the position of the SVR 52, the unbalance rate and the voltage deviation can be improved as compared with the case where the conventional HVR is arranged.

As described above, in the HVR according to the present embodiment, the reference point voltage and the unbalance rate when the respective controlled quantities are used are obtained for all the combinations of the controlled quantities of the voltage of the three-phase AC power. The HVR according to this embodiment controls the voltage of the three-phase AC power in the distribution system by a combination in which the line voltage is within an appropriate range and the unbalance rate is minimized. As a result, the unbalance rate in the distribution system can be improved and the voltage deviation can be reduced, and the efficiency of voltage control of the distribution system by the HVR can be improved.

FIG. 6 is a block diagram of the evaluation device according to the second embodiment. The evaluation device 6 according to the present embodiment has the same functions as the HVR 1 of the first embodiment, that is, the control quantity set generation unit 14, the post-control information acquisition unit 15, the control quantity extraction unit 16 within a predetermined condition, and the optimum control quantity identification unit 17. Have. Further, the evaluation device 6 has an analysis unit 18. In the following description, the description of the operation of each part similar to that of the first embodiment will be omitted.

The post-control information acquisition unit 15 receives input of information on a combination of control quantities generated by the control quantity set generation unit 14 from an input device 7 such as a personal computer. Further, the post-control information acquisition unit 15 receives the input of the configuration information of the distribution system 2 from the input device 7. Here, the post-control information acquisition unit 15 may receive input of a plurality of configuration information having different introduction rates of the photovoltaic power generation system as the configuration information of the distribution system 2.

Further, the post-control information acquisition unit 15 receives input of information on the positions of SVRs 51 to 55 shown in FIG. 1 from the input device 7. Then, the post-control information acquisition unit 15 obtains an estimated value of the secondary side voltage and the passing current when the HVR1 is arranged at each of the positions of the SVRs 51 to 55. Next, the post-control information acquisition unit 15 obtains the reference point voltage and the unbalance rate of all combinations of control quantities for each arrangement position.

The control amount extraction unit 16 within a predetermined condition extracts a candidate combination for each arrangement position from the reference point voltage and the unbalance rate obtained by the post-control information acquisition unit 15.

The optimum control amount specifying unit 17 specifies a combination of control amounts that minimizes the unbalance rate for each arrangement position from the candidate combinations extracted by the control amount extraction unit 16 within a predetermined condition. Further, when the post-control information acquisition unit 15 receives input of a plurality of configuration information having different introduction rates of the photovoltaic power generation system, the optimum control amount specifying unit 17 has each introduction rate of the photovoltaic power generation system for each arrangement position. Specify the combination of control quantities that minimizes the imbalance rate according to the above.

The analysis unit 18 acquires from the optimum control amount specifying unit 17 a combination of control amounts that minimizes the unbalance rate for each arrangement position. Then, the analysis unit 18 simulates the voltage control in the distribution system 2 for each arrangement position by using the combination of the control amounts that minimizes the unbalance rate, and acquires the control result for each distribution position. For example, as a control result, the analysis unit 18 acquires the maximum voltage unbalance rate, which is the maximum value of the voltage unbalance rate after control by the HVR 1, and the average value of the number of taps of the SVRs 51 to 55 per day.

Further, when the post-control information acquisition unit 15 receives input of a plurality of configuration information having different introduction rates of the photovoltaic power generation system, the analysis unit 18 responds to each introduction rate of the photovoltaic power generation system for each arrangement position. Simulate and get the control result.

Here, each control result when HVR1 is arranged by exchanging any one of SVRs 51 to 55 arranged on the distribution system 2 in FIG. 1 with HVR1 will be described. FIG. 7 is a diagram showing the maximum voltage unbalance rate for each arrangement position.

The horizontal axis of FIG. 7 represents the PV introduction amount, which is the introduction rate of the photovoltaic power generation system in the distribution system 2. Further, the vertical axis of FIG. 7 represents the maximum voltage unbalance rate, which is the maximum value of the voltage unbalance rate after control by HVR1 according to the first embodiment. Then, in FIG. 7, the maximum voltage unbalance rate for each of the six arrangement positions is shown for each PV introduction amount shown on the horizontal axis. In the introduction rate of each photovoltaic power generation system, each bar graph shows the maximum voltage unbalance rate when HVR1 is not arranged in order from the left and when HVR1 is arranged at each position in the order of SVR 51 to 55.

When the introduction rate of the photovoltaic power generation system is 0%, 10% and 20%, the maximum voltage unbalance rate in the state where the HVR1 is arranged at the position of the SVR 52 becomes the minimum. Further, when the introduction rate of the photovoltaic power generation system is 30%, the maximum voltage unbalance rate in the state where the HVR1 is arranged at the position of the SVR53 becomes the minimum. However, the difference in the maximum voltage unbalance rate when the introduction rate of the photovoltaic power generation system is 30% is small between the state where the HVR1 is arranged at the position of the SVR 52 and the state where the HVR1 is arranged at the position of the SVR 53. Therefore, as a whole, it can be said that the maximum voltage unbalance rate can be suppressed most when the HVR1 is arranged at the position of the SVR 52.

Further, FIG. 8 is a diagram showing the number of tap changes for each arrangement position. The horizontal axis of FIG. 8 represents the PV introduction amount, which is the introduction rate of the photovoltaic power generation system in the distribution system 2. Further, the vertical axis of FIG. 8 represents the average value of the number of taps per vehicle, which is the average value of the number of taps for 15 days of SVR 51 to 55 according to the first embodiment. Then, in FIG. 8, the average value of the number of taps per vehicle for each of the six arrangement positions is represented for each PV introduction amount represented on the horizontal axis. In the introduction rate of each photovoltaic power generation system, each bar graph shows the maximum voltage unbalance rate when HVR1 is not arranged in order from the left and when HVR1 is arranged at each position in the order of SVR 51 to 55. However, the number of tap changes when the HVR1 is not arranged represents the maximum value of the number of tap changes of SVRs 51 to 55.

When the introduction rate of the photovoltaic power generation system is 0%, 10% and 20%, the average value of the number of taps per unit in the state where the HVR1 is arranged at the position of the SVR 52 becomes the minimum. Further, when the introduction rate of the photovoltaic power generation system is 30%, the average value of the number of taps per unit in the state where the HVR1 is arranged at the position of the SVR53 becomes the minimum. However, when the introduction rate of the photovoltaic power generation system is 30%, the average value of the number of taps is slightly different between the state where the HVR1 is arranged at the position of the SVR52 and the state where the HVR1 is arranged at the position of the SVR53. Therefore, as a whole, it can be said that the state in which the HVR1 is arranged at the position of the SVR 52 can suppress the average value of the number of taps per unit most. By suppressing the number of taps, it is possible to suppress fluctuations in voltage and efficiently optimize the voltage of the distribution system 2.

From the control results shown in FIGS. 7 and 8, it is considered that the state in which the HVR1 is arranged at the position of the SVR 52 can minimize the unbalance rate and the number of taps. Therefore, in the analysis unit 18, the position of the SVR 52 is the HVR1. Judged as the optimum installation position.

In this way, the analysis unit 18 identifies the arrangement position with the best control result, and notifies the HVR1 administrator of the control amount of the voltage of the three-phase power when the HVR1 is arranged at the specified arrangement position and the arrangement position. do.

Here, in this embodiment, the optimum placement position is determined using the configuration information of the distribution system 2 when the introduction rates of the solar systems are different, but the method of determining the optimum placement position by the evaluation device 6 is this. Not exclusively. For example, the information of the actual distribution system 2 that already exists may be input to the evaluation device 6 to cause the evaluation device 6 to determine the optimum arrangement position in the distribution system 2. In that case, since the introduction rate of the photovoltaic power generation system is determined, the analysis unit 18 acquires one control result at each position and identifies the arrangement position having the best control result from the control results.

As described above, the evaluation device according to the present embodiment can determine the optimum placement position of the HVR by comparing the control results corresponding to each placement position. Then, the HVR administrator receives notification from the evaluation device of information on the combination of the optimum placement position and the optimum control amount, and introduces the HVR into the distribution system based on the information to perform the optimum voltage control. be able to.

1 HVR
2 Distribution system 3 Distribution substation 4 Node 6 Evaluation device 7 Input device 10 Voltage control unit 11 Pre-control information acquisition unit 12 Judgment unit 13 Storage unit 14 Control amount set generation unit 15 Post-control information acquisition unit 16 Control amount within predetermined conditions Extraction unit 17 Optimal control amount identification unit 18 Analysis unit 41 Transformer 42 Transmission line 43 Consumer 51-55 SVR
2001-203 Transmission route

Claims (7)

A voltage control device placed on a distribution system that transmits three-phase AC power.
A generator that generates a combination of control quantities for the voltage of each phase using a plurality of predetermined control quantities for the voltage of each phase of the distribution system.
A voltage acquisition unit that acquires the voltage of each phase at a predetermined point on the distribution system when the voltage is controlled using each control amount for each combination of control quantities generated by the generation unit.
An extraction unit that extracts a candidate combination from the combination of the control amounts based on the voltage of each phase acquired by the voltage acquisition unit.
A specific unit that specifies a combination of control amounts that minimizes the voltage imbalance rate of the controlled voltage of each phase at the predetermined point from the candidate combinations extracted by the extraction unit.
A voltage control device including a control unit that controls the voltage of each phase by using a combination of control quantities specified by the specific unit. A pre-control voltage acquisition unit that acquires the pre-control voltage of each phase before controlling the voltage using a combination of control quantities specified by the specific unit at the predetermined point on the distribution system.
Based on the pre-control voltage of each phase acquired by the pre-control voltage acquisition unit, it is determined whether or not voltage control is performed, and when it is determined that voltage control is performed, the generation unit, the voltage acquisition unit, The voltage control device according to claim 1, further comprising a determination unit for causing the extraction unit and the control unit to perform processing and controlling the voltage of each phase. The voltage control device according to claim 1 or 2, wherein the voltage acquisition unit estimates the voltage of each phase at the predetermined point by using a vector Line Voltage Drop Compensator (LDC) method. The extraction unit is a combination of the control amounts in which the unbalance rate of the voltage of each phase is smaller than the predetermined unbalance specified value and the voltage of each phase at the predetermined point is within the predetermined appropriate range. The voltage control device according to any one of claims 1 to 3, wherein the voltage control device is a candidate for a combination of the control amounts. It is a voltage control method in a distribution system that transmits three-phase AC power.
Using a plurality of predetermined control amounts for the voltage of each phase of the distribution system, a combination of control amounts for the voltage of each phase is generated.
For each combination of generated control quantities, the voltage of each phase at a predetermined point on the distribution system when the voltage is controlled using each control amount is acquired.
Based on the obtained voltage of each phase, a candidate combination is extracted from the combination of the control amounts.
From the extracted candidate combinations, the combination of the control amount that minimizes the voltage imbalance rate of the controlled voltage of each phase at the predetermined point is specified.
A voltage control method characterized in that the voltage of each phase is controlled using a combination of specified control quantities. It is a voltage control method in a distribution system that transmits three-phase AC power.
Using a plurality of predetermined control amounts for the voltage of each phase of the distribution system, a combination of control amounts for the voltage of each phase is generated.
For each combination of generated control quantities, the voltage of each phase at a predetermined point on the distribution system when the voltage is controlled using each control amount is acquired.
Based on the obtained voltage of each phase, a candidate combination is extracted from the combination of the control amounts.
From the extracted candidate combinations, the combination of the control amount that minimizes the voltage imbalance rate of the controlled voltage of each phase at the predetermined point is specified.
A voltage control program characterized by having a computer perform a process of controlling the voltage of each phase using a combination of specified control quantities. It is an evaluation device for a voltage control device placed on a distribution system that transmits three-phase AC power.
A position selection unit that selects a plurality of arrangement positions for arranging voltage control devices on the distribution system, and
A generator that generates a combination of control quantities for the voltage of each phase using a plurality of predetermined control quantities for the voltage of each phase of the distribution system.
For each arrangement state in which the voltage control device is arranged at any of the arrangement positions selected by the position selection unit, a voltage is applied using each control amount for each combination of control amounts generated by the generation unit. A voltage acquisition unit that acquires the voltage of each phase at a predetermined point on the distribution system when controlled, and a voltage acquisition unit.
An extraction unit that extracts a candidate combination from the combination of the control amounts based on the voltage of each phase acquired by the voltage acquisition unit for each of the arrangement states.
From the candidate combinations for each of the arrangement states, a specific unit that specifies a combination of control quantities that minimizes the voltage imbalance rate of the controlled voltage of each phase at the predetermined point, and
The voltage fluctuation of the distribution system by voltage control when the combination of the control amounts specified by the specific unit is used for each arrangement state is analyzed, and the voltage is based on the control result for each arrangement state obtained by the analysis. It is characterized by having an analysis unit that specifies the placement position of the control device and notifies the combination of the control amount specified by the specific unit when the voltage control device is placed at the specified placement position and the specified placement position. Evaluation device.

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