JP2015177607A - Countermeasure construction determination device and method for distribution system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine an optimal countermeasure construction that minimizes cost of the countermeasure construction for a distribution system while settling a load-side voltage within predetermined upper and lower limit values.SOLUTION: In a countermeasure construction determination device 10 for a distribution system, load-flow calculation or/and status estimation of the distribution system are performed on the basis of measurement data 22 of the distribution system and load-flow calculation data 21 of the distribution system to calculate voltages of nodes. A low conversion voltage converted into a load-side voltage is calculated from the voltages of the nodes and a pole transformer tap value 23 of the distribution system, and a voltage margin is calculated from a differential between the low conversion voltage and a predetermined voltage upper/lower limit value. When the voltage margin is equal to or less than a predetermined threshold, a plurality of countermeasure cost items are calculated which relate to a change of the pole transformer tap value and relate to installation of a voltage regulator for performing a voltage regulation. A plurality of evaluation functions are compared which are evaluated on the basis of the voltage margin and the plurality of countermeasure cost items.

Description

  The present invention relates to a countermeasure work determination apparatus and method for determining a voltage countermeasure work of a distribution system using a countermeasure cost and a voltage margin with respect to a voltage upper and lower limit value as an evaluation index.

  If the voltage of the distribution system cannot be kept within the proper range by switching the transformer (LRT: Load Ratio Tap-changer) of the distribution substation in the existing equipment configuration, the pole transformer tap value Change or install an automatic voltage regulator (SVR: Step Voltage Regulator) within the proper range. The following method is shown for optimal installation of SVR.

  For example, Patent Document 1 discloses a method of setting the system state by power flow calculation and minimizing the number of voltage regulators newly installed in the target system. Patent Document 2 discloses a method for obtaining the distribution state of the line voltage in the distribution system and obtaining the optimum installation position of the SVR.

JP 2006-296030 A JP 2008-31323 A

  In the methods described in Patent Documents 1 and 2, cost minimization is only a countermeasure by minimizing the number of installed SVRs. For this reason, for example, even when it is cheaper to change the tap value of the pole transformer whose voltage is constantly high in the system, there is a possibility of calculating a solution of installing one SVR.

  In this way, in a distribution system with multiple voltage countermeasures, there is a practical method for determining voltage countermeasures by comparing the cost of countermeasures by changing the pole transformer tap value and the cost of countermeasures by newly installing a voltage regulator. It has not been established, and the optimum countermeasure construction that minimizes the cost of the countermeasure construction of the distribution system while keeping the load side voltage within the predetermined upper and lower limit values has not been determined.

  In order to solve the above problems, the present invention is a distribution system countermeasure work determination device for determining a countermeasure work for a distribution system, a measurement database for storing measurement data of the distribution system, and a pole transformer tap of the distribution system The pole transformer tap value database for storing values, the power flow calculation database for storing power flow calculation data for the power distribution system, and the power flow calculation or / and state estimation of the power distribution system from the measurement data and the power flow calculation data The voltage of each node is obtained, the low voltage converted voltage converted to the load side voltage from the voltage of each node and the pole transformer tap value is obtained, and the voltage margin is obtained from the difference between the low voltage converted voltage and a predetermined voltage upper and lower limit value. A voltage margin representing a degree of voltage is obtained, and when the voltage margin is equal to or less than a predetermined threshold, a countermeasure cost for changing the tap value of the pole transformer and a voltage regulator for performing voltage adjustment are installed. A calculating unit that determines a countermeasure work by obtaining a plurality of countermeasure costs related to the device and comparing a plurality of evaluation functions evaluated based on the voltage margin and the plurality of countermeasure costs.

  A method invention corresponding to the present invention is also included.

  According to the present invention, the optimum countermeasure construction that minimizes the cost of the countermeasure construction of the distribution system is determined while keeping the load side voltage within a predetermined upper and lower limit value.

It is a distribution system schematic diagram provided with the countermeasure work determination apparatus by one Example of this invention. It is a block diagram of the countermeasure construction determination apparatus by one Example of this invention. It is a flowchart which shows the countermeasure construction determination algorithm by one Example of this invention. It is the schematic of the countermeasure required location calculated | required by step S2 by one Example of this invention. It is the schematic of the SVR optimal installation result calculated | required by step S5 by one Example of this invention. It is the schematic of the countermeasure required location calculated | required by step S2 by the other Example of this invention. It is the schematic of the SVR optimal installation result calculated | required by step S5 by the other Example of this invention. It is the schematic of the combination result of the tap value change calculated | required by step S6 by the other Example of this invention, and the optimal installation of SVR.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram of a power distribution system provided with a voltage countermeasure work determination device according to an embodiment of the present invention, and shows the configuration of the power distribution system 100, the voltage countermeasure work determination device 10 and a communication network 190 connecting them. . The distribution system 100 includes a distribution substation 110, a node (bus) 120, a distribution line 140 connecting them, a pole transformer 160 connected to the node 120, a load 150 and a generator connected to the pole transformer and below. 130 and a sensor 170 installed in the distribution line. The sensor 170 measures line current, flow power factor, active power P, reactive power Q, node voltage V, and the like, and sends information to the voltage countermeasure work determination apparatus 10 via the communication terminal station 180 and the communication network 190. The voltage regulator 300 is installed in series with the line of the power distribution system 100.

  FIG. 2 is a configuration diagram of the voltage countermeasure work determination apparatus 10 according to an embodiment of the present invention. A display device 11, an input unit 12 such as a keyboard and a mouse, a computer (CPU) 13, a communication unit 14, a RAM 15, and various databases are connected to the bus line 30. As the database, there are tidal current calculation data 21, measurement data 22, pole transformer tap value data 23, and program data 24. A computer (CPU) 13 executes a calculation program to instruct image data to be displayed, search for data in various databases, and the like. The RAM 15 is a memory for temporarily storing calculation result data such as display image data, power flow calculation results, measurement data list, settling parameter calculation results, and SVR ideal voltage calculation results. Based on these data, the CPU 13 generates necessary image data and displays it on the display device 11 (for example, a display screen).

  The memory in the voltage countermeasure construction determination apparatus is roughly divided into four databases. The tidal current calculation data 21 stores system configuration data representing the line constant Z (= R + jX) indicating the impedance of the line 140, the load / power generation amount, and the connection status of the system lines and nodes. The measurement data 22 includes information such as line current, current power factor, active power P, reactive power Q, load and power generation amount, and node voltage V measured by the sensor 170 in the distribution system 100 for each time section. Is stored. In addition to this, the measurement data 22 includes line current, current power factor, active power P, reactive power Q, load and power generation amount, and node voltage V for each time section obtained by power flow calculation and state estimation calculation. Such information is also stored. The pole transformer tap value data 23 stores a data set of pole transformers and pole transformer tap values in the system. The program data 24 stores a tidal current calculation program, a state estimation calculation program, a countermeasure required place determination program, and a countermeasure construction determination program, which are calculation programs. These programs are read by the CPU 13 as necessary, and calculation is executed.

  FIG. 3 is a flowchart illustrating an LDC parameter determination algorithm according to an embodiment of the present invention. The calculation processing contents of the voltage countermeasure work determination apparatus 10 shown in this figure will be described. The figure shows the procedure for determining the countermeasure work based on the voltage measurement data of the sensors in the distribution system and the voltage calculated using the measurement data corresponding to the SVR output voltage Vsvr, the SVR passing active power Psvr, and the reactive power Qsvr. An example is shown. Hereinafter, the flow of processing will be described.

  First, in step S1, data necessary for processing is read. A period to be analyzed is determined, and measurement data for each hour of the period to be analyzed is read.

  Next, in step S2, the voltage of each node is calculated by power flow calculation or state estimation. Using the voltage calculation result and the pole transformer tap value, the low-voltage converted voltage is calculated as shown in Equation 1.

[Equation 1]
Vlow = Vhigh / Tap × 105
Here, Vlow represents the low-voltage converted voltage of the node, Vhigh represents the high-voltage of the node, and Tap represents the pole transformer tap value of the node.

  From the calculated low-voltage converted voltage, the voltage margin is calculated as shown in Equation 2.

[Equation 2]
Vm1 = VU-Vlow (<0)
Or Vm1 = Vlow−VL (<0)
Here, VU is a node voltage upper limit (low voltage conversion), and VL is a node voltage lower limit (low voltage conversion) set value. From Equation 2, the voltage margin is negative for nodes whose low-voltage converted voltage is higher than the voltage upper limit value or lower than the voltage lower limit value. Nodes with negative voltage margin are considered as places where countermeasures are required.

  Next, in step S3, when the low-voltage converted voltage at the place where countermeasures are required is higher than the upper limit value, the pole transformer tap value is increased. The voltage is calculated by estimation, and the voltage margin at this time is defined as Vm1 ′.

  When there is no countermeasure necessary part, the countermeasure cost 1 is calculated | required like several 3 by step S4.

[Equation 3]
COST1 = COSTtr × Ntr
Here, COST1 is the countermeasure cost 1 only by changing the pole transformer tap value, COSTtr is the unit cost (setting value) of the construction cost for changing the pole transformer tap value, and Ntr is the number of countermeasures required.

  From the countermeasure cost COST1 and the voltage margin Vm1 ′, the evaluation function 1 is calculated as shown in Equation 4.

[Equation 4]
F1 = a × Vm1′−b × COST1
Here, F1 is the evaluation function 1 of the countermeasure work only for changing the pole transformer tap value, a is a weighting coefficient (setting value) for the voltage margin, and b is a weighting coefficient (setting value) for the countermeasure cost.

  Next, in step S5, a system in which the voltage regulator is optimally arranged is created, and the voltage of each node is calculated by power flow calculation or state estimation. The low-voltage converted voltage is calculated as shown in Equation 1, and the voltage margin obtained by Equation 2 is defined as Vm2. When a voltage regulator is installed, voltage flow calculation and state estimation are performed, and a voltage margin Vm2 'at this time is obtained. Similarly, if there is no part that needs to be handled, calculate the cost of the countermeasure.

  Measure cost 2 is calculated as shown in Equation 5.

[Equation 5]
COST2 = COSTreg × Nreg
Here, COST2 is a countermeasure cost 2 only due to the installation of the voltage regulator, COSTreg is a unit cost (set value) of the construction cost for installing the voltage regulator, and Nreg is the number of voltage regulators installed.

  The evaluation function 2 is obtained from the countermeasure cost COST2 and the voltage margin Vm2 'in the same manner as in Equation 4.

  Next, in step S6, after changing the pole transformer tap value, a system in which the voltage regulator is optimally arranged is created, and the voltage of each node is calculated by power flow calculation or state estimation. The low-voltage converted voltage is calculated as shown in Equation 1, and the voltage margin obtained by Equation 2 is defined as Vm3. When the pole transformer tap value is changed and the voltage regulator is installed, voltage flow calculation and state estimation are performed, and the voltage margin Vm3 'at this time is obtained. Similarly, if there is no part that needs to be handled, calculate the cost of the countermeasure.

  Measure cost 3 is calculated as shown in Equation 6.

[Equation 6]
COST3 = COSTtr × Ntr ′ + COSTreg × Nreg
Here, Ntr ′ is the number of pole transformers whose pole transformer tap values are changed.

  From the countermeasure cost COST3 and the voltage margin Vm3 ', the evaluation function 3 is obtained in the same manner as Equation 4.

  Next, in step S7, the evaluation function 1, the evaluation function 2, and the evaluation function 3 are compared, and the countermeasure work having the largest evaluation function is determined as the voltage countermeasure work of the distribution system.

  FIG. 4 is a countermeasure-necessary part obtained in step S2 according to an embodiment of the present invention. Deviation occurs only in one pole transformer. In step S3, the tap value is changed and the voltage is calculated again. When the deviation is resolved, the countermeasure cost 1 is calculated in step S4. Since the countermeasure cost is a cost for changing the tap value of one pole transformer, the countermeasure cost 1 is the same value as the tap value change unit price. The evaluation function 1 is calculated using the voltage margin at this time and a preset weighting factor.

  FIG. 5 is an SVR optimum installation result obtained in step S5 according to an embodiment of the present invention. Since the countermeasure cost is the cost of installing one voltage regulator, the countermeasure cost 2 is the same value as the voltage regulator installation unit price. The evaluation function 2 is calculated using the voltage margin at this time and a preset weighting factor. Next, the combination of tap value change and SVR optimum installation is considered in step S6. However, since the voltage deviation is resolved when the tap value is changed at one place, the evaluation function 3 becomes the same value as the evaluation function 1, and measures are taken. Is either a tap value change at one pole transformer or one voltage regulator. In general, since the unit price for changing the tap value is lower than the unit price for installing the voltage regulator, the countermeasure cost 1 is cheaper. When the weighting factor is appropriately set, the evaluation function 1 and the evaluation function 3 are maximized, and the voltage countermeasure work calculated by this method is a tap value change at one pole transformer.

  FIG. 6 is a countermeasure-necessary part obtained in step S2 according to another embodiment of the present invention. A total of p + q pole transformers have deviated. In step S3, the tap value is changed and the voltage is calculated again. When the deviation is resolved, the countermeasure cost 1 is calculated in step S4. Since the countermeasure cost is a cost for changing the tap value of the pole transformer p + q, the countermeasure cost 1 is the tap value change unit price × (p + q). The evaluation function 1 is calculated using the voltage margin at this time and a preset weighting factor.

  FIG. 7 is an SVR optimum installation result obtained in step S5 according to another embodiment of the present invention. In the system where the lower limit deviation occurs in the trunk line and the upper limit deviation occurs in the branch line, even if one voltage adjustment device is installed before the branch, the voltage deviation is not resolved, resulting in the installation of two units. Since the countermeasure cost is the cost of installing two voltage regulators, the countermeasure cost 2 is the voltage regulator unit installation cost × 2. The evaluation function 2 is calculated using the voltage margin at this time and a preset weighting factor.

  FIG. 8 shows a combination result of the tap value change obtained in step S6 and the optimum installation of the SVR. Changing the tap value of the q pole transformer on the branch line solved the upper limit deviation of the branch line, resulting in the installation of one voltage regulator on the main line. The countermeasure cost is the cost of changing the tap value of the pole transformer q and the cost of installing one voltage regulator, so the countermeasure cost 3 is tap value change unit price × q + voltage regulator unit installation unit cost. The evaluation function 3 is calculated using the voltage margin at this time and a preset weighting factor. When the number of changes p of the pole transformer tap value is extremely large, the countermeasure cost 3 is cheaper than the countermeasure cost 1. When the tap value change unit price × q is cheaper than the voltage adjustment device installation unit price, the countermeasure cost 3 is cheaper than the countermeasure cost 2. If the weighting factor for the countermeasure cost is set large, the evaluation function 3 is maximized, and the voltage countermeasure work calculated by this method is a combination of the tap value change and the optimal installation of the SVR. The difference between the countermeasure cost 2 and the countermeasure cost 3 is small, and a weighting coefficient for the voltage margin is set in consideration of a future change in the load amount predicted in the target system and a change in the power generation amount due to the introduction of natural energy, and the SVR2 When the voltage margin is larger in the optimum installation of the base than in the combination of the tap value change and the optimum installation of the SVR, the evaluation function 2 becomes the maximum, and the voltage countermeasure work calculated by this method is the optimum installation of the two SVRs.

  In this way, by calculating the evaluation function using the countermeasure cost, the weight coefficient of the countermeasure cost, the margin for the voltage upper and lower limits, and the weight factor for the margin for the voltage upper and lower limits, the countermeasure construction that matches the operator's purpose is determined. It becomes possible to do.

10 Countermeasure Work Determination Device 11 Display Device 12 Input Means 13 Computer (CPU)
14 Communication means 15 RAM
21 Power Flow Calculation Data 22 Measurement Data 23 Pillar Transformer Tap Value Data 24 Program Data 30 Bus Line 100 Distribution System 110 Distribution Substation 120 Node 130 Generator 140 Distribution Line 150 Load 160 Pillar Transformer 170 Sensor 180 Communication Terminal 190 Communication network 200 Voltage regulator

Claims (7)

A power distribution system countermeasure work determination device for determining power distribution system countermeasure work,
A measurement database that stores the measurement data of the power distribution system;
A pole transformer tap value database for storing pole transformer tap values of the distribution system;
A tidal current calculation database for storing tidal current calculation data of the power distribution system;
From the measurement data and the power flow calculation data, the power flow calculation or / and state estimation of the distribution system is performed to determine the voltage of each node, and the voltage of each node and the pole transformer tap value are converted to the load side voltage. A low voltage conversion voltage is obtained, a voltage margin representing a voltage margin is obtained from a difference between the low voltage conversion voltage and a predetermined voltage upper and lower limit value, and when the voltage margin is a predetermined threshold value or less, the tap value of the pole transformer The countermeasure construction cost is determined by comparing a plurality of evaluation functions evaluated based on the voltage margin and the plurality of countermeasure costs by obtaining a plurality of countermeasure costs relating to the change of the voltage and a plurality of countermeasure costs relating to the installation of the voltage regulator for performing voltage adjustment. A calculation unit for determining
A power distribution system countermeasure work determination device characterized by comprising: In the power distribution system countermeasure work determination device according to claim 1,
The calculator is
A distribution system characterized by calculating a countermeasure cost related to a change in tap value of the pole transformer when the voltage margin is equal to or greater than a predetermined threshold and a countermeasure cost related to installation of a voltage regulator that performs voltage adjustment Measures construction decision device. In the power distribution system countermeasure work determination device according to claim 1 or 2,
The calculator is
A countermeasure work determination apparatus for a power distribution system, wherein the evaluation function is obtained by weighting the voltage margin and the plurality of countermeasure costs. In the distribution system countermeasure construction determination device according to claim 3,
The weighting of the voltage margin is set based on a subsequent load amount and power generation amount change prediction for each node, and a countermeasure work determination device for a power distribution system. In the distribution work countermeasure work determination device according to any one of claims 1 to 4,
The calculator is
Further, the evaluation function in the case where only the countermeasure cost related to the installation of the voltage adjustment device for performing the voltage adjustment and the evaluation function in the case where only the countermeasure cost related to the change in the tap value of the pole transformer is obtained, A measure for a distribution system characterized by comparing the evaluation functions when both the measure cost for changing the tap value of the pole transformer and the measure cost for installing the voltage regulator for voltage adjustment are compared. Construction decision device. In the distribution system countermeasure work determination device according to any one of claims 1 to 5,
The calculator is
As a result of the comparison, the countermeasure work determining apparatus for the distribution system is characterized in that the countermeasure work when the evaluation function is maximized is determined. A power distribution system countermeasure work determination method for determining power distribution system countermeasure work,
Obtain the voltage of each node by calculating the power flow of the power distribution system and / or estimating the state from the power distribution system measurement data and power flow calculation data, and calculate the load side voltage from the voltage of each node and the pole transformer tap value of the power distribution system. A low voltage converted voltage converted to a voltage, a voltage margin representing a voltage margin is obtained from a difference between the low voltage converted voltage and a predetermined voltage upper and lower limit value, and when the voltage margin is a predetermined threshold value or less, the pole transformer By calculating a plurality of countermeasure costs related to the change of the tap value and a plurality of countermeasure costs related to the installation of the voltage regulator for voltage adjustment, and comparing a plurality of evaluation functions evaluated based on the voltage margin and the plurality of countermeasure costs A countermeasure construction determination method for a power distribution system, wherein the countermeasure construction is determined.