JP6884070B2 - Power system voltage regulators, methods, and systems - Google Patents

Description

The present invention relates to a voltage optimization device, method, and system for optimizing the voltage of a power system.

The power system is a large-scale system constructed by combining many devices and control methods for a stable supply of electric power. The state of the power system can be expressed by physical quantities such as voltage, current, power, and frequency, and these states have a surface spread along the system configuration and are accompanied by temporal changes. Since the system state changes greatly depending on the power generation and load connected to the system, various control devices and control methods are used to maintain the steady state.

One of the factors that causes the power system to deviate from the steady state is the interconnection of distributed power sources, which has been increasingly introduced into the power system in recent years. For example, renewable energy such as solar power generation and wind power generation may be connected to the end side of the power system in a distributed manner compared to conventional generators, and the amount of power generation may be affected by weather conditions. is there. Then, by flowing the generated power into the system, changes in the system state such as occurrence of power flow reversal (reverse power flow) and voltage fluctuation occur. For example, fluctuations in the amount of power generated by renewable energy may fluctuate the voltage of the line to which the voltage fluctuations are connected, and deviate from the upper and lower limits of the voltage.

In order to install a voltage regulator and optimize the voltage, it is necessary to correctly grasp the state and characteristics of the power system. Here, the state of the power system is assumed to be a physical quantity of a phenomenon occurring in the power system such as voltage and current. Further, as the characteristics of the power system, numerical values, parameters, etc. associated with the equipment configuration of the power system such as line impedance may be used comprehensively. Voltage regulators such as SVR (Step Voltage Regulator) and SVC (Static Var Composer) are used to control their own equipment by arranging measuring equipment at their own end (or primary side or secondary side) to measure the system status. To do. The method of using the measured signal for controlling the own machine is sometimes called autonomous control.

Recent advances in information and communication technology have made it possible to transmit data at high speed. Therefore, technology that utilizes the measurement signals of sensors installed in the power system is expected. For example, there are measuring devices such as a sensor switch (or a switch with a sensor) and a PMU (Phasor Phasorement Unit). In addition to the voltage adjusting devices such as SVR and SVC described above, the state values of the power system such as voltage, current, and phase collected by the measuring device in the sensor switch are aggregated by using a transmission means such as power line carrier or optical cable. it can.

There is a technique for analyzing, estimating, or predicting the state of the power system using the measurement signals aggregated in this way, and controlling the state of the power system so as to reach the target state. In addition to the above-mentioned autonomous control, it may be called remote settling in which the calculated settling value is set remotely, or centralized control in which the control signal is set remotely.

There is a demand for a voltage optimization technique for dealing with line voltage fluctuations using such a control method. As a specific known technique, for example, in Patent Document 1, "in order to estimate the power system impedance, active power and ineffective power are output to the interconnection point with the existing power system that supplies power to the load, and the active power and the active power and the active power are output. The voltage of the interconnection point and the active power and the ineffective power when the invalid power is intentionally changed are detected in sequence in chronological order, and the voltage fluctuation of the interconnection point voltage, the load power consumed by the load, and the load power consumed by the load. Simultaneous equations obtained by substituting the voltage, active power, and ineffective power of the interconnection point voltage detected for a plurality of time series into the relational expression consisting of the power system impedance (R + jX) of the existing power system. The power system impedance (R + jX) is estimated by solving the above. "

In Patent Document 2, first, based on the voltage measurement data of the sensor and the measurement data corresponding to the SVR output voltage Vsvr, the SVR passing active power Psvr, and the ineffective power Qsvr, first, the voltage of the analysis target node of the distribution system within the analysis target period. The voltage is obtained by finding the ideal output voltage Vs of the voltage automatic regulator so that it is within the upper and lower limit range, and then performing multiple regression analysis of the correlation between this ideal value Vs and the measured value of the electric power of the distribution system. The configuration of "determining the settling parameters of the automatic regulator" is disclosed.

Japanese Unexamined Patent Publication No. 2006-230050 Japanese Unexamined Patent Publication No. 2010-220283

The prior art disclosed in Patent Documents 1 and 2 is characterized in that an impedance required for controlling a voltage adjusting device is estimated for the purpose of voltage optimization of a power system.

However, all of these technologies were developed before the introduction of renewable energy expanded, and do not consider the phenomenon caused by the introduction of renewable energy in the power system. Specifically, there are voltage fluctuations caused by distributed power sources (power generation), changes in the distribution range of active power and ineffective power, changes in load points due to fluctuations in power supply and load, and the like. The conventional technique using linear approximation causes an error due to a large change in state due to the introduction of renewable energy.

Patent Document 1 prepares a relational expression that linearly approximates the voltage fluctuation of the interconnection point voltage, the load power P + jQ consumed by the load, and the power system impedance R + jX of the existing power system. However, this method has the following problems.
(1) This method is expressed by a relational expression that linearly approximates the impedance. However, the approximation error becomes apparent as the state change becomes larger due to the introduction of renewable energy.
(2) In order to put this method into practical use, it is necessary to intentionally fluctuate the active power and the inactive power, which incurs equipment costs and operating costs, and gives them to other consumer equipment by fluctuating. The impact must be considered. Moreover, it is not practical to install such a new device for all the lines for which impedance estimation is desired.

Patent Document 2 discloses a method of calculating line impedance by regression analysis of a measurement signal. According to Patent Document 2, a three-dimensional space in which the bottom two axes are the active power P and the ineffective power Q and the vertical axis is the sending voltage V is prepared, and the measurement signal is plotted on the space. The slope of the plane obtained by the regression analysis corresponds to the resistance R in the P-axis direction and the reactance X in the Q-axis direction. This document is characterized in that it can correspond to an arbitrary power factor by having the coordinate axes of the active power P and the ineffective power Q, and the accuracy is improved by regression analysis, as compared with the technology that precedes it. However, this method reveals the following problems due to the increase in the introduction of renewable energy.
(1) Conventionally, since the equipment connected to the grid only needs to handle consumption and the range in which the active power P and the ineffective power Q are distributed is limited, such a linear approximation may be established. However, with the introduction of renewable energy, the consumption of equipment and power generation will be dealt with, and the operating range of the active power P and the reactive power Q will be expanded, so that the error due to linear approximation cannot be ignored.
(2) This method is based on the premise that the load point is constant. Here, the load point is a connection point of a virtual load that is a contraction of the load device and the power generation device connected to the line, and the place is indicated by the line impedance from the sending side. However, the introduction of renewable energy introduces the consumption of equipment and power generation, and as the amount of power generated by the introduction of renewable energy increases, the load point is not constant and changes over time. For this reason, the regression analysis method cannot respond to changes in the load point and causes an error.

The above-mentioned prior art does not provide a control method when a plurality of types of voltage adjusting devices such as SVR and SVC are used in combination.

The above-mentioned conventional technology is a technology for a power system before the introduction of renewable energy, and does not consider the phenomenon that occurs in the power system due to the introduction of renewable energy. Therefore, when applied to a recent system in which the system state fluctuates greatly due to the introduction of renewable energy, the control error becomes large and the practicality becomes inferior.

From the above, in the present invention, the voltage drop equation between two points set in the power system can be accurately identified by using the measurement signal, and the state of the power system can be estimated accurately. It is intended to provide equipment, methods, and systems.

From the above, in the present invention, "a voltage optimization device for a power system provided with a voltage adjusting device for connecting a distributed power source that provides renewable energy and controlling the voltage of the power system, which is installed in the power system. It was identified as a first input unit that obtains a state quantity indicating the state of the power system from the measuring device, and an identification unit that obtains the voltage drop equation of the power system as a PQV solid identified by an equal voltage circle using the state quantity. A voltage optimization device for a power system, which comprises an output unit that determines an output to be given to a voltage adjusting device using a PQV solid. "

Further, in the present invention, "a method for optimizing the voltage of a power system including a voltage adjusting device for connecting a distributed power source that provides renewable energy and controlling the voltage of the power system, and a measuring device installed in the power system. The state quantity indicating the state of the power system is obtained from, and the voltage drop equation of the power system is obtained as a PQV solid identified by an equal voltage circle using the state quantity, and the output given to the voltage adjusting device using the identified PQV solid. A method for optimizing the voltage of the power system, which is characterized by the determination of. "

Further, in the present invention, "a method for optimizing the voltage of a power system including a voltage adjusting device for connecting a distributed power source that provides renewable energy and controlling the voltage of the power system, and a measuring device installed in the power system. The state quantity indicating the state of the power system is obtained as a measurement signal from, the first operating point of the power system is calculated using the measurement signal, and an equal voltage circle that satisfies the constraint condition of the power system is calculated to obtain an equal voltage circle. A power characteristic characterized in that a second operating point is set in the sandwiched region, a control locus from the first operating point to the second operating point is calculated, and a control amount is obtained based on the control locus. How to optimize the voltage of the system. "

Further, in the present invention, "a method for optimizing the voltage of a power system including a voltage adjusting device for connecting a distributed power source that provides renewable energy and controlling the voltage of the power system, and a measuring device installed in the power system. The state quantity indicating the state of the power system is obtained as a measurement signal from, and a plurality of measurement signals measured at different times are substituted into the voltage drop equation between two points of the power system as a combination of active power, ineffective power, and voltage. A coefficient (setting) for calculating the first operating point, calculating the control amount from the first operating point to the second operating point as a combination of active power, ineffective power, and voltage, and calculating the control amount. A method for optimizing the voltage of the power system, which is characterized by calculating the value). "

Further, in the present invention, "a voltage optimization system for a power system that connects a distributed power source that provides renewable energy, and is a voltage control device that is installed in the power system and controls the voltage of the power system, and the voltage adjustment device. The voltage optimization device is equipped with a voltage optimization device that gives an output to the power system, and the voltage optimization device has a first input unit that obtains a state quantity indicating the state of the power system from a measuring device installed in the power system, and a voltage drop type of the power system. , A voltage of a power system including an identification unit obtained as a PQV solid identified by an equal voltage circle using a state quantity, and an output unit that determines an output to be given to a voltage adjusting device using the identified PQV solid. The optimization system. "

According to the present invention, there is an effect that the voltage drop equation between two points set in the power system can be accurately identified by using the measurement signal, and the state of the power system can be estimated accurately.

Further, according to the embodiment of the present invention, it is possible to obtain the effect of accurately calculating the control amount or the set value of the voltage adjusting device by using the measurement signal. Then, by using the control amount, the accuracy of control for voltage optimization can be improved, and control can be performed according to the characteristic change of the power system.

The figure which shows the typical configuration example of the electric power system in recent years. The figure which shows the voltage drop of the section set in the power system. The figure which shows the PQV solid in the three-dimensional space which has active power P, active power Q, and voltage V as coordinate axes. The figure which shows an example of the variation of a PQV solid. The figure which shows the difference between the exact formula of this invention and the conventional approximate formula in a schematic comparative display. The figure which shows the structural example of the voltage optimization system of the electric power system which concerns on this invention. The figure for demonstrating the concept at the time of setting the section between two points of an electric power system. The figure explaining the variation of how to handle the load side end point when setting a section. The flowchart which shows the procedure of identification of the voltage drop equation by the optimum calculation. The schematic diagram which displayed a plurality of measured measurement signals on a PQV solid. The figure which shows the control area (or the existence range of an operating point) which calculates a control amount. The figure which showed the upper and lower limit voltage of a line which is a constraint condition as an equivoltage circle on a PQV solid. The figure explaining the relationship between the control locus and voltage adjustment at the time of controlling each coordinate axis independently. The figure explaining the method of calculating a control locus by angle division. The figure explaining the method of calculating a control locus by distance division. The figure explaining the relationship between the control locus and voltage adjustment. The flowchart which shows the calculation procedure of the control amount at the time of performing centralized control. A flowchart showing a procedure for calculating a settling value used for autonomous control or remote settling. The figure which shows the system configuration of autonomous control. The figure which shows the system configuration of centralized control. The figure which shows the structure at the time of sequential calculation using the captured measurement signal. The figure which shows the structure which stores the captured measurement signal in a database and calculates in advance. The figure which shows the structure when the voltage adjustment device is SVR. The figure which shows the structure when the voltage adjustment device is SVC. The figure which takes the voltage and PQ of the sending side as a coordinate axis and shows the drawing result. The figure which shows the structure when the verification means for judging the validity of a calculated control amount or a set value is provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like. The following examples show specific examples of the contents of the present invention, and the present invention is not limited to these examples, and is by those skilled in the art within the scope of the technical idea disclosed in the present specification. Various changes and modifications are possible.

Further, although the present invention describes the configuration of implementation for a single-phase system, it goes without saying that the present invention can be applied to an arbitrary system such as a three-phase system.

The state of the electric power system changes due to the influence of the interconnected load, the power generation of photovoltaic power generation PV, etc., as well as the line impedance and the like. Focusing on the line voltage, since the upper and lower limit voltages are specified, it is necessary to optimize the voltage in order to suppress the voltage fluctuation and keep it within the range. In particular, in recent years, from the viewpoint of utilizing natural energy, the voltage distribution tends to fluctuate due to the interconnection of distributed power sources such as photovoltaic PV to the grid, and a control method for voltage optimization is required.

In order to keep the line voltage within the upper and lower limit ranges, in addition to voltage adjustment by a substation LRT (Load Radio control Transformer), control is performed using a voltage adjustment device installed on the line. Here, as the voltage adjusting device, there are SVR, TVR, SVC, SC, ShR and the like.

The SVR (Step Voltage Regulator) is also called a high-voltage automatic voltage regulator, and the transformation ratio between the primary side and the secondary side is switched by the tap changer inside the device. TVR (Thyristor Voltage Regulator) enables high-speed switching by tapping with a semiconductor element. SVC (Static Var Composer), SC (Static Condenser), and ShR (Stat Reactor) are devices that control voltage with reactive power. These devices differ in the types of control amounts such as transformation ratio, active power, and reactive power, as well as the capacity (magnitude) of the control amount and the response speed at which the control amount is output. In addition, these devices include a method of collecting measurement signals (signal type, measurement location, measurement interval, etc.) and a method of calculating control signals (type of control signal, location of calculation device, time) for grasping the state of the line. The interval, etc.), the setting method of the device parameters, etc. (setting with the changeover switch on the device, setting remotely using the transmission means, etc.), etc. are different. There is a demand for a method for appropriately controlling these in combination.

Methods for controlling these voltage regulators are generally classified into autonomous control, remote control (or remote settling), and centralized control. Autonomous control realizes control using the measurement signal at its own end by setting the set value used to calculate the control amount of the voltage adjusting device in advance. For example, SVR is a control called LDC. Set the line impedance (RX) and reference voltage to determine the position of the load center point or voltage constant point. Since the voltage fluctuation status differs depending on the line, the set value is determined based on the measurement signal in advance or the past record.

On the other hand, the remote setting enables voltage adjustment corresponding to a change in the system state by calculating the set value of the voltage adjusting device using the measurement signal and setting it remotely via the communication means.

In centralized control, the control amount of the voltage adjusting device is calculated using the measurement signal and set remotely. In the example of SVR, it corresponds to calculating the tap value and setting it in SVR without interposing a set value such as line impedance (RX).

The present invention provides a method and an apparatus for calculating a control amount or a set value applied to centralized control, remote settling, and autonomous control using a measurement signal in an electric power system.

In the first embodiment, a geometrical solution of the voltage drop equation will be described.

The power system is composed of a combination of power generation equipment, load equipment, voltage adjustment equipment, and the like. In order to grasp the state of the power system, there is a method of installing a measuring device and collecting a measurement signal, and there is a method of estimating the state of the power system based on a power equation or a voltage drop equation.

The present invention is characterized in that, with respect to a section constituting the power system, a means for solving an unknown number included in the voltage drop equation by substituting a measurement signal into the voltage drop equation of the section is provided. Here, in order to obtain a measurement signal, a switch with a sensor (hereinafter abbreviated as a sensor switch), a PMU (Phasor Measurement Unit), or a sensor built in a voltage adjusting device is used as a measuring device on the line. , These measurement points can be set as the end points of the section. Further, even in a place where there is no measuring device, the calculated value by the state estimation, the tidal current calculation, or the like can be used.

FIG. 1 shows a typical configuration example of a power system in recent years. Here, 110 is a distribution substation, 120 is a node (bus), 130 is a line, 140 is a measuring device, 150 is an SVR, 160 is a photovoltaic generator, 170 is a load device, and the photovoltaic generator 160. It is a characteristic of the power system in recent years that the proportion of power generation is increasing. The impedance Z of the line 130 is represented by the resistance R and the reactance X. The SVR 150 is installed at an appropriate place, estimates the voltage at the virtual point on the load side, and controls so that the estimated voltage is within a predetermined voltage range. At that time, the measuring device 140, for example, on the load side It is used by measuring voltage, current, etc.

FIG. 2 schematically shows an example of an electric power system including a load 170 and a photovoltaic power generator 160 on the load side of the SVR 150, and is a diagram showing a voltage drop in a section set in the electric power system. In this case, the voltage distribution on the line 130 on the load side is significantly different between sunny weather and cloudy weather, and the terminal side voltage tends to be high especially in sunny weather, and reverse power flow may occur in some cases. Therefore, there is a need to correctly estimate the voltage drop on the line 130.

FIG. 2 is a diagram focusing on a section of the power system (section between nodes N1 and N2) having the sending side and the load side as end points in the power system of FIG. Here, a subscript s is added to the sending side of the section and a subscript r is added to the load side to distinguish them. When the voltage on the sending side is Es, the voltage on the load side is Er, the line impedance is Z, and the current is J. The voltage drop from the sending side to the load side is expressed by Eq. (1). Each variable in Eq. (1) is a complex number or a vector. Here, the line impedance Z = R + jX, where R represents resistance and X represents reactance.

When j is an imaginary symbol and the symbol ^* is a conjugate, the active power P, the reactive power Q, and the load side voltage Er have the relationship of the following equation (2).

Here, in the voltage drop equation of Eq. (1), the system state is expressed by a non-linear complex equation. In this regard, in the past, when photovoltaic power generation was not widespread, in order to simplify the calculation, the resistance R, which is the actual part of the line impedance, was sufficiently small, the change in the phase difference angle was sufficiently small, etc. It was common to treat it as a linear approximation formula with the assumption of. For example, in non-patent documents (Shokodo, Izumi Hayashi, "Power System", first edition published on September 15, 1976, power transmission characteristics in a simple system on page 41, paragraph 3.2), the phase difference angle θ is small. We are conducting systematic analysis by solving mathematical formulas on the premise of.

However, when analyzing the state of a power system in which a distributed power source such as photovoltaic power generation is introduced, the error caused by the above linear approximation cannot be ignored. For example, when targeting a distribution system, the component of the resistance R of the line impedance is large, and the assumption does not hold. In addition, the interconnection of distributed power sources expands the operating range of the power system, which increases the approximation error.

Therefore, in the present invention, in order to solve the above problems and grasp the state of the power system with high accuracy, the equations (1) and (2) are used as a nonlinear complex equation without being approximated. Eq. (3) can be obtained by obtaining the active power P (real part) and the ineffective power Q (imaginary part) from the equations (1) and (2). Here, φ indicates the phase difference angle between the voltage on the feed side and the voltage on the load side.

Further, the equation (4) can be obtained by modifying the equation (3). Equations (3) and (4) are circular equations for the active power P and the active power Q, and the center and radius of the circle are determined by the voltage Es, Er, and the line impedance Z (R + jX). I will call it.

The center position (Sx, Sy) and radius Sr of the equivoltage circle can be obtained by the following equation (5).

FIG. 3 shows a three-dimensional shape (hereinafter referred to as a PQV solid) represented by Eq. (3) or (4) in a three-dimensional space having active power P, reactive power Q, and voltage V as coordinate axes. It is a thing. In other words, it is a three-dimensional shape formed by stacking equivoltage circles. In the following description, when the voltage is treated as a coordinate axis or a coordinate value, the symbol V may be used instead of the symbol E.

In the PQV solid, the active power P, the active power Q, and the voltage V on the load side are specified as coordinate values, and the voltage Es, the line impedance Z, and the phase difference angle on the sending side are used as variables. Here, as an example, the sending voltage Es is normalized to 1, the resistance R of the line impedance and the reactance X are set to a ratio of 1: 1, and the phase difference angle is 2π from −π to + π as the angle parameter of the equivoltage circle. I'm changing. Under these conditions, the PQV solid represents all combinations of active power P, inactive power Q, and voltage V for which the voltage drop equation holds.

If the PQV solid is viewed along the V axis, equipotential circles on a two-dimensional plane with PQ as the coordinates can be observed. In FIG. 3, this is displayed as a projection drawing of an equivoltage circle. The projection drawing of the equipotential circle shows that the center and size of the circle change according to the load-side voltage V. The center of the circle moves to the right in the figure once as the load-side voltage V increases, and then moves to the left while increasing the diameter.

Further, if the PQV solid at this time is viewed along the Q axis, a curve (PV curve) on the PV plane can be observed. Further, a power phase difference angle curve focusing on the relationship between the phase difference angle and the active power P, which are the angle parameters of the equivoltage circle, can be illustrated as shown in FIG. FIG. 4 is a diagram showing an example of variations of the PQV solid.

These can be treated as variations in which the coordinate axes and observation directions of the PQV solid are changed. The present invention is characterized by comprising means for drawing and displaying a PQV solid and variations thereof. Hereinafter, in the present invention, when it is not necessary to distinguish them, they will be referred to as PQV solids including variations.

As described above, in the present invention, in order to accurately grasp the state of the power system, equations (1) and (2) are used as non-linear complex equations without being approximated, and active power P, reactive power Q, and active power Q, and It shows a PQV solid represented by Eq. (3) or (4) in a three-dimensional space with voltage V as the coordinate axis. In other words, it is on a three-dimensional shape created by stacking equal voltage circles. , The status of the power system is grasped and displayed. The voltage drop equation of the power system is grasped as an equal voltage circle using the active power P, the reactive power Q, and the voltage V.

The voltage drop equation of the present invention is tentatively referred to as an exact equation, and an equation in which the conventional phase difference angle is limited is referred to as an approximate equation, and these differences are schematically compared and displayed by FIG. FIG. 5 shows an exact formula and an approximate formula in a three-dimensional space having active power P, reactive power Q, and voltage V as coordinate axes.

In making this comparison, the basic equations (voltage drop and definition of PQ) are equations (1) and (2).

The exact formula obtained by expanding the formulas (1) and (2) is represented by the formula (6). The resulting PQV solid in which equivoltage circles are stacked is shown on the left side of FIG.

The approximate expression obtained by expanding the equations (1) and (2) is expressed by the equation (7). In this approximate expression, since it is assumed that the phase difference angle θ is near 0, it does not form a circle and its operating surface is flat. The flat operating surface of the approximate expression is shown on the right side of FIG.

FIG. 5 geometrically displays the difference between the exact formula and the approximate formula. In both cases, the phase difference angle θ is changed from −π to + π. At the phase difference angle θ = 0, the two match, but the larger the phase difference angle, the more dissociated. This dissociation becomes an approximation error. In addition, since there is a difference in the spatial slope (voltage and P, or ratio of change between voltage and Q) created by both, an approximation error will occur when performing analysis using the rate of change between voltage and PQ. Become. When the distributed power sources are connected, the phase difference angle is not always near 0, so using an approximate expression may lead to an erroneous judgment. In addition, when creating simultaneous equations using a plurality of measurement signals, using an approximate equation may prevent the solution from converging.

FIG. 6 shows a configuration example of a voltage optimization system for an electric power system according to the present invention. The voltage optimization system includes, for example, a power system including a measuring instrument 140 and an SVR 150, and a voltage optimization device 1.

The voltage optimization device 1 includes at least two input units 2 and 3. The input unit 2 is an input unit for obtaining information such as current, voltage, active power, and invalid power of various parts of the power system as a state quantity in the power system from the measuring instrument 140, and the input unit 3 is a power system. It is an input unit for evaluating the state of the power supply or giving a setting value for limiting the power supply.

The processing unit 4 executes the exact formula described in the first embodiment to obtain a PQV solid, determines the first point indicated by the input obtained by the input unit 2 on the PQV solid, and obtains the PQV solid by the input unit 3. The second point indicated by the setting input is defined on the PQV solid. And the difference between the first point and the second point is obtained. The difference is directly or further adjusted and indirectly output from the output unit 5 and given to, for example, the SVR 150 in the form of a set value or manipulated variable.

In the second embodiment, the features of the present invention in the voltage optimization device 1 and the like will be described. First, for example, in the operation of a power system, there are constraint conditions such as an upper limit voltage and a lower limit voltage of a line. In the present invention, by using the PQV solid, equipotential circles corresponding to the upper limit voltage and the lower limit voltage of the line can be illustrated. As a result, the operating ranges of the active power P, the active power Q, and the voltage V that satisfy the constraints of the upper and lower limit voltages can be geometrically grasped.

By using the PQV solid, the state of the power system can be illustrated as one point on the PQV solid (corresponding to the first point described above and hereinafter referred to as an operating point). The present invention is characterized in that the current operating point is specified on the PQV solid by using the measurement signal. At the same time, it is characterized in that a target operating point satisfying the constraint condition (corresponding to the second point described above and hereinafter, a target operating point) is set on the PQV solid. Then, the locus of the controlled variable from the current operating point to the target operating point is calculated so as to satisfy the constraint condition. The present invention is characterized in that the above control locus is geometrically calculated by using a PQV solid.

The phenomenon of the power system that can be seen from the geometrical observation of the PQV solid and the features of the present invention that utilize it are summarized.

Feature 1: Measurement signal and PQV solid The appearance of the PQV solid changes depending on the characteristics of the power system. For example, the center of the equivoltage circle changes with the ratio of the resistance R of the line impedance Z and the reactance X. When the resistance R is 0, the center of the equivoltage circle is on the Q axis of the reactive power, and the center of the circle moves as the resistance R (positive value) increases. On the contrary, the variable that creates the PQV solid can be calculated from the measurement signal. The present invention is characterized in that a PQV solid is identified using a measurement signal.

Feature 2: Non-linear characteristics of voltage fluctuation It can be seen that the active power P, the reactive power Q, and the voltage V have the non-linear characteristics related to each other in the PQV solid. The wider the operating range is due to the interconnection of distributed power sources, the greater the influence of the non-linear characteristics. The present invention presents a voltage adjustment method and apparatus in consideration of non-linear characteristics by using a PQV solid.

Feature 3: About voltage adjustment The current operating point of the power system can be set on the PQV solid using the measurement signal. Further, the target operating point on the PQV solid can be set, for example, for voltage adjustment. In the present invention, the control amount from the current operating point to the target operating point is calculated as a combination of active power P, reactive power Q, and voltage V.

Feature 4: About SVR transformation ratio When there is a transformer such as SVR (or LRT) on the sending side, the relationship between the transformation ratio and the active power P and the active power Q can be illustrated on the PQV solid. For example, it can be seen that the higher the voltage on the sending side, the wider the range of power that can be consumed on the load side.

Feature 5: Upper and lower limit voltage of voltage optimization The upper limit voltage and the lower limit voltage of the line, which are the constraint conditions of voltage optimization, can be overlaid on the PQV solid. In order to optimize the voltage, the target operating point is set within the range of the upper and lower limit voltages, and the required PQV control amount is calculated. The present invention presents a method and an apparatus for calculating a control amount that satisfies the constraints of upper and lower voltage.

Feature 6: Stable operation region The PQV solid has two V values (higher solution and lower solution) for one active power P and invalid power Q coordinates. Here, the higher solution exists in the region where the PQV solid can be observed from above the V axis. The lower solution has a larger current and a larger line loss than the higher solution, so it is not practically used. The present invention is characterized in that the existence range of the operating point is limited to the upper side of the PQV solid, and the operating point and the control amount are calculated as a higher solution of the PQV solid.

Feature 7: Effect of error It is known that the measurement signal often contains an error. In the present invention, when the measurement signal contains an error, the calculation method is selected and executed so as to minimize the influence of the error. In addition, the effect of error can be quantified by statistically assuming a normal distribution and quantifying the mean and variance. For example, an operating point can be illustrated as a point (region) having a size based on the variance. Further, by indexing the comparison between the operating point and the upper and lower voltage limits as a voltage margin in consideration of dispersion, a control signal for preventing voltage deviation can be calculated.

An embodiment will be described based on a voltage drop equation for a section having two locations at both ends in the power system. By connecting the sections continuously, the entire line can be analyzed. Alternatively, the interval can be treated as a contraction of the remaining interval. The two points at both ends of the section can be the points where the measurement signal can be collected by the measuring device. In addition, the section can be set by regarding the state value calculated by state estimation or tidal current calculation as a measurement signal.

There are several variations in how to make the above sections. The present invention can cope with these variations.

As a variation 1, in a system configuration having an SVR on the sending side, the sending voltage is controlled by tap switching.

As a variation 2, in a system configuration in which an SVC is provided on the load side, the invalid power Q of the load is controlled.

As a variation 3, in a system configuration in which load-side devices are connected, the load-side power consumption, the active power of the amount of power generation, and the invalid power are adjusted.

In the present invention, the control amount for realizing voltage optimization is calculated by using the measurement signals collected from the measuring instruments having these system configurations. Here, the measurement signal is used for the next calculation.
(1) Step 1: Identification of the voltage drop equation for the section of the power system using the measurement signal (2) Step 2: Calculation of the operating point using the measurement signal and the voltage drop equation Perform this procedure with a time lag. For example, the procedure 1 may be calculated based on the past actual data, and the procedure 2 may be calculated in real time based on the measurement signal. Alternatively, both may be executed at the same time using the same real-time measurement signal. Hereinafter, other examples will be described.

In the third embodiment, the process of the above procedure 1 (identification of the voltage drop type (PQV solid) using the measurement signal) will be described.

The power system is composed of a combination of lines and voltage regulators. FIG. 7 is a diagram for explaining a concept when setting a section between two points of the power system.

In the present invention, as shown in FIG. 7, a section between two points of the power system is set as a section, and the system state is grasped by using the voltage drop equation of the section. In the example of FIG. 7, from the LRT of the distribution substation 110 to the sensor switch 140a which is a measuring device, from the sensor switch 140a to the primary side of the SVR 140, from the secondary side of the SVR 140a to the sensor switch 140c, the sensor switch 140c. It shows that it was set in 4 sections from to the sensor switch 140d.

The end point of the section to be set may be a place where a measuring device such as a sensor switch or a voltage adjusting device is located as a place where a measurement signal can be collected. By dividing a long-distance line into a plurality of sections, a voltage drop equation can be created for each section.

FIG. 8 is a diagram illustrating variations in how to handle the load side end points when setting the section. As shown in FIG. 8, there are variations in how to handle the end points on the load side. One of the variations is a method of making a voltage drop equation focusing only on the equipment connected to the end point S22 on the load side, as shown in a of FIG. As shown in b of FIG. 8, another method of variation is a method of treating as a virtual load point by creating a voltage drop equation including a device connected to the line connected to the load side. The analysis of the former is easy to understand, but the actual measurement signal is the measurement signal including the equipment in the subsequent stage. In the present invention, the load side end point of the section can be treated as a virtual load point.

Further, when the measurement signal cannot be collected, a point where the state value is calculated by using a calculation method such as power flow calculation or power system state estimation may be set as an end point. The setting location can be set based on an index such as a voltage margin. The voltage margin can be used as an index of concern about voltage deviation by calculating it as a difference value comparing the current voltage value and the upper and lower limit voltages, for example.

The variables included in the voltage drop equation include active power P, reactive power Q, load side voltage Es, sending side voltage Es, line impedance Z (R + jX), and phase difference angle φ between Es and Er. Depending on the type of measuring device and the installation location, there are variables that can be obtained as measurement signals and variables that cannot be obtained.

For example, consider a case where the sending-side voltage Es, the load-side voltage Es, the active power P, and the reactive power Q can be measured. At this time, it is assumed that the line impedance between two points on the line and the phase difference angle are unknown. The state of the power system determined by these measurement signals is positioned as an operating point on the PQV solid. Calculating the unknown line impedance and the phase difference angle is equivalent to solving the simultaneous equations so that the operating points at multiple times are located on the PQV solid. Whereas the conventional method using the approximate expression of voltage drop may ignore the R component of the line impedance and the voltage phase difference angle, the present invention explicitly deals with the R component of the line impedance and the voltage phase difference angle. It is a feature. The present invention does not limit the combination of available measurement signals and unknowns, and can similarly create simultaneous equations.

The present invention is characterized in that measurement signals at a plurality of times are substituted into a voltage drop equation and simultaneously solved to solve an unknown variable. In addition to using an algebraic solution method, if the measurement signal contains an error, the least squares method, optimization calculation, statistical calculation method, or the like can be used. You can also use brute force or heuristic solutions. A solution method may be selected in consideration of errors and omissions included in the measurement signal. The present invention does not limit these solutions. A technique for identifying a variable using a measurement signal is sometimes called identification. The present invention is characterized in that the PQV solid of the target power system is identified by using the measurement signal. Further, the present invention is characterized in that a PQV solid is identified by using a state value calculated by a calculation method such as power flow calculation or power system state estimation instead of a measurement signal.

An example is an example of a procedure for creating a voltage drop equation for a section sandwiched between two measuring instruments. The measurement signals of voltage V, current I, and power factor by the measuring device are collected and used in the server. By converting these measurement signals, the active power P and the ineffective power Q can be obtained. The unknown number of the voltage drop type has three variables: the line impedances R and X, and the phase difference angle φ between the voltage on the sending side and the voltage on the loading side.

In order to solve the voltage drop equations including the three unknowns, three sets of voltage drop equations are created and combined by substituting the measurement signals at the three measurement times t. If the measurement signal does not include an error, a simultaneous solution can be obtained by an analytical method. If an error is included, an appropriate solution such as least squares method, multiple regression, probability distribution, or optimization calculation can be used by increasing the number of measurements.

FIG. 9 is a flowchart showing the procedure for identifying the voltage drop equation by the optimum calculation. FIG. 9 shows an example of a procedure by particle swarm optimization (PSO) classified into a metaheuristic method as a solution method when an error is included in the measurement signal.

In the first processing step S10 of the flow shown in FIG. 9, measurement signals at a plurality of times are input. At this time, the measurement signals are the sending-side voltage, the load-side voltage, the load-side active power P, and the load-side active power Q. Further, in the processing step S10, a voltage drop equation including an unknown variable that cannot be measured is prepared. Here, the unknown variables are the line impedance and the phase difference angle. FIG. 10 is a schematic view showing a plurality of measured measurement signals on a PQV solid. However, here, the PQV solid is shown on the PQ plane.

In the processing step S20, the line impedance Z and the phase difference angle θ are initially set as particles (groups) in the search space.

In the processing step S30, the particle coordinates (Z, θ) and the measurement signal PQ are substituted into the voltage drop equation to calculate the error (sum of squares) between the calculated value of the load side voltage and the measured value.

In the processing step S40, the end / continuation is determined using the convergence condition.

When the determination result is continuous, in the processing step S50, the coordinates (Z, θ) of the particles (group) are updated and the process returns to the processing step S30.

When the determination result is completed, in the processing step S60, (the child coordinates are output as a solution.

For example, the line impedance, which was an unknown variable, is calculated by a series of processes shown in FIG. 9, and the voltage drop equation is identified. This result can be used to draw a PQV solid.

The present invention does not limit the search method to PSO, and an appropriate method can be used. Alternatively, a full search method that tries all combinations may be used.

The measurement time t (or time interval) for collecting the measurement signal can be determined based on the situation of the measurement target. When the state of the power system fluctuates due to some factor, the measurement time t can be determined based on the situation. The present invention does not limit the factors that cause the state change of the electric power system, and does not fix the measurement time t described above. When it is determined that the fluctuation is small, the interval of the measurement time t can be widened, and when it is determined that the fluctuation is large, the measurement time t can be set to a short cycle. Further, a means for determining the validity / invalidity of the measurement signal may be prepared, and the measurement time t may not be set when the measurement signal is invalidated.

For example, with the introduction of a distributed power source, the power consumption on the load side and the amount of power generated by the distributed power source may be balanced and the power flow may become zero. At this time, the active power P, the active power Q, and the power factor cannot be defined, and the measured values have no meaning. Therefore, the present invention is characterized in that the measurement time t is set based on the situation of such an electric power system, and a means for determining the validity / invalidity of the measurement signal is provided.

Here, there may be variations depending on the characteristics of the system known in advance, the type and time interval of the measurement signal, the type of the solution method for obtaining the simultaneous solution, and the like. This procedure can be repeated at appropriate time intervals or based on some starting conditions. It may be configured to improve the accuracy of the calculation result by repeating the calculation.

The data used for the identification of the voltage drop type includes a method of using the measurement signal collected and accumulated in advance, a method of sequentially using the input signal, and a method of using the prediction signal.

Using the accumulated measurement signals collected by the measuring device in the target system, the voltage drop equations can be combined to obtain the solution in order to obtain the characteristics of the target system. It is also possible to calculate the solution for each condition based on the conditions related to the state change such as the weather condition and the day of the week. By accumulating the calculation results in a database or the like, it is possible to switch the calculation results to be used based on the conditions.

The measurement signals to be collected using the measuring device in the target system are sequentially input, and the simultaneous solutions can be sequentially obtained as soon as sufficient conditions for making the voltage drop equations simultaneous are satisfied. Calculation results based on the current state can be used.

By obtaining a prediction signal related to the state of the power system, it is possible to obtain a solution by simultaneously forming voltage drop equations using the prediction signal. The control amount can be calculated based on the prediction in advance. By performing predictive control, it is possible to obtain the effect of improving responsiveness with a small amount of control by starting countermeasures in advance before an event actually occurs.

The present invention can utilize any of the above procedures, or a combination of the above procedures.

In the fourth embodiment, the calculation procedure and the calculation method of the control amount of the voltage adjusting device will be described.

In the present invention, as the voltage optimization of the line, the control amount for controlling the voltage adjusting device is calculated in order to keep the line voltage within the upper and lower limit voltage ranges. In addition to SVR, SVC, etc. as voltage adjusting devices, voltage optimization is realized by controlling the power generation and power consumption of power generation devices and load devices.

Therefore, in the present invention, the voltage drop type (PQV solid) is identified by using the measurement signal for the target power system. In addition, the current operating point is specified using the measurement signal. Then, a target operating point that satisfies the constraint conditions such as the upper and lower limit voltages is set, and the locus of the control amount from the current operating point to the target operating point is set on the PQV solid. In addition, by including the time parameter in the control trajectory, control that takes into account the time response characteristics of the device is realized.

Here, the problem of voltage optimization will be described based on a geometric solution method using a PQV solid. As described above, the PQV solid takes a high solution and a low solution, but in order to realize stable operation, the present invention calculates the control amount with the high solution of the PQV solid as the existence range of the operating point. This region is an upper region that is not hidden when the PQV solid is observed from the V-axis + side.

FIG. 11 shows a control region (or an existing range of operating points) for which the present invention calculates a control amount. In FIG. 11, the PQV three-dimensional display format shown in FIG. 10 will be used for description. As an example, the current operating point S1 is set to P = 0 and Q = 0 on the PQV solid, the power consumption of the load device is a positive value P (+), and the power generation amount of the power generation device is a negative value P (−). When the distributed power source is not connected to the load side, the operating point S1 is determined only by the power consumption, so that the range (P ≧ 0) of the operating point S1 on the PQV solid is limited. When a distributed power source is connected to the load side, the active power P fluctuates positively or negatively depending on the combination of power consumption and power generation amount, so that the range of the operating point S1 on the PQV solid is expanded.

As a conventional method, there is a method of approximating a part of a PQV solid with a plane (linear approximation) assuming that the range of the operating point S1 is sufficiently narrow. The plane approximated by this conventional method is as shown on the right side of FIG. 5 as the operating surface of the approximate expression. However, in reality, reverse power flow is generated due to the expansion of the introduction of distributed power sources, so the approximation error cannot be ignored in the linear approximation method.

The present invention treats the voltage drop equation as a non-linear complex equation without approximating it, and eliminates the approximation error. This corresponds to handling the PQV solid based on the voltage drop equation in the PQV space whose coordinate axes are the active power P, the ineffective power Q, and the voltage V, which are variables included in the voltage drop equation. By using the PQV solid, it is possible to explicitly show the combination of all the variables for which the voltage drop equation holds. In addition, line impedance and voltage phase difference angle can be handled parametrically.

By the way, the upper and lower limit voltages of the line are numerical values determined by laws, regulations, etc., and do not indicate the characteristics of the power system derived from the voltage drop equation. However, equipotential circles that match the upper and lower voltage can be created from the voltage drop equation.

Therefore, as shown in FIG. 12, the present invention is characterized in that the upper and lower limit voltages of the line, which is a constraint condition, are expressed as equipotential circles on the PQV solid. Then, the present invention is characterized in that the control amount satisfying the constraint of the upper and lower voltage is calculated by placing the target operating point S2 in the region sandwiched between the two equivoltage circles corresponding to the upper limit voltage and the lower limit voltage. ..

FIG. 12 is a diagram in which the upper and lower limit voltages of the line, which is a constraint condition, are represented on the PQV solid as equivoltage circles. Here, it is assumed that the upper and lower limit voltages are determined along the equipotential circle, the operating point S1 is currently on the power generation region side (negative value P (−)), and the voltage is higher than the upper limit voltage. For power system management in this case, it is necessary to control the voltage adjusting device to keep the voltage value below the upper limit voltage, and this target operating point is N, and the control from the current operating point S1 to the target operating point S2. The locus determines the control amount of the voltage adjusting device.

Note that the control trajectory is determined by the difference in whether the control target of the voltage adjustment device is a reactor or a capacitor, or whether it is by notch control or continuous quantity control, so what is used as the voltage adjustment device to perform the target operation. The control amount also differs depending on whether the point S2 is reached.

As described above, the present invention is characterized in that the characteristics of the active power P, the reactive power Q, and the voltage V included in the power system and the upper and lower limit voltages which are the constraint conditions are collectively handled on the PQV solid. Another feature is to clearly indicate the control locus from the current operating point to the target operating point on the PQV solid.

By using an equipotential circle, the relationship between the active power P, the reactive power Q, and the voltage V can be obtained by a geometric solution. The relationship between the upper and lower limit voltages, which are the constraint conditions, and the controlled amounts of active power and active power can be grasped graphically, and the validity of the numerical values can be judged graphically. It can be said that there is a basis for the present invention to be characterized by a geometric solution method using a PQV solid, as a geometric solution method using drawing or the like has been established in the field of mathematics.

Needless to say, a solution can be obtained by using a computer program prepared based on the geometric solution method. In addition, drawing an equal voltage circle is effective for humans to visually understand the operating principle, and it is explained by using it as an opportunity to explain the technical content to a wide variety of stakeholders in an easy-to-understand manner. It is effective in fulfilling responsibilities.

In this way, the method of plotting the state of the power system using the PQV solid and finding the solution can be characterized as one of the geometric solutions of the power system. An effect that cannot be achieved can be obtained.

If the time response of the voltage regulator is fast enough, the control amount can be applied without delay. However, if there is a voltage regulator whose time response is not sufficiently fast, it will take time. Conventionally, the control amount may be calculated without considering the time response of this voltage adjusting device.

Let ΔP, ΔQ, and ΔV be the control amounts from the current operating point S1 calculated in the PQV space to the target operating point S2. Here, the method of taking the control locus from the current operating point S1 to the target operating point S2 is not unique, and the control result may differ.

Many voltage regulators have a controlled amount along the coordinate axes in PQV space. For example, the SVR can be controlled along the V axis by the transformation ratio by tap switching. The SVC can be controlled along the Q axis by the invalid power output. The load / power generation equipment can be controlled along the P-axis and the Q-axis by the active power and the ineffective power. These voltage regulators differ in the time response of the control output.

Next, the relationship between the control locus and the voltage adjustment will be described with reference to FIGS. 13a, 13b, 13c, and 13d.

FIG. 13a is a diagram showing the relationship between the control locus and the voltage adjustment when the coordinate axes are controlled independently. Here, as shown in FIG. 13a, if each control amount is independently output in two stages such as ΔP after outputting ΔQ, an error in voltage adjustment due to the unoutput control amount occurs in the control process. To do. Further, even if ΔP, ΔQ, and ΔV are output at the same time, an error in voltage adjustment by a voltage adjusting device having a slow response may appear as a voltage fluctuation. Further, if the voltage adjustment error is collected as a measurement signal at the next measurement time, the feedback system will be configured, and the control may become unstable.

The present invention is characterized in that a control locus that combines ΔP, ΔQ, and ΔV is calculated in order to realize voltage control in consideration of the time response of the voltage adjusting device. The control locus is expressed as ΔP (t), ΔQ (t), and ΔV (t) with the time t (0 ≦ t ≦ T) as a parameter. The elapsed time T of the control locus may be set to be the same as the collection cycle of the measurement signal, or may be set longer. The present invention realizes stable control by determining the elapsed time T in consideration of the installation location of the voltage adjusting device and the time response.

The first method of realizing the control locus according to the present invention is to calculate the control locus by the angle division shown in FIG. 13b. The present invention geometrically calculates a control locus by using a PQV solid. For example, for constant voltage control, the control locus from the current operating point S1 (t = 0) to the target operating point S2 (t = T) may be set on an equivoltage circle. As shown in FIG. 13b, the control quantities ΔP (t), ΔQ (t), and ΔV (t) can be calculated by dividing the equivoltage circle into angles within the elapsed time T. Dividing the angle between two points on the circumference using the circle equations can be easily calculated using geometric relationships.

The second method of realizing the control locus according to the present invention is to calculate the control locus by the distance division shown in FIG. 13c. In this method, as shown in FIG. 13c, the control locus connecting the current operating point S1 and the target operating point S2 with a straight line is defined by the time parameter t (0 ≦ t ≦ T) as described in (8) below. It can be calculated by the formula.

This method can be applied when the current operating point S1 and the target operating point S2 have different voltages. The calculation is simple, but when the control locus intersects the equipotential circle, the voltage fluctuation becomes large.

The third method of realizing the control locus according to the present invention is to calculate the control locus by morphing the vector shown in FIG. 13d. In this method, the control locus can be calculated geometrically using the vector notation. As shown in FIG. 13d, the current operating point S1 and the target operating point S2 are represented by vectors from the origin of the equivoltage circle on which they are mounted. Then, the origin, the angle, and the length of the vector are divided in the time T to create a control locus. Let Sr1 be the vector pointing to the current operating point and Sr2 be the vector pointing to the target operating point. The parameters are the origin (x, y), the angle α, the length L, and the elapsed time t. For example, the difference of length L is expressed by Eq. (9).

Then, the vector Sr1 is moved / rotated / extended (morphed) along the elapsed time t (0 ≦ t ≦ T) to match the vector Sr2 at the elapsed time T. The relationship at this time is shown by Eq. (10).

In this way, the control locus with time as a parameter can be calculated from the locus from the vector Sr1 to Sr2 (the locus of the vector end point). The present invention is characterized in that a control locus connecting a current operating point to a target operating point is calculated by geometric calculation using a PQV solid.

By the way, from the above equation (4), it can be seen that the center position of the equivoltage circle changes with the square of the load side voltage, and the radius changes with the term of the square of the load side voltage. However, as shown in Eq. (11), when the change is expressed by Δ, if Δ is sufficiently small, the square term (Δ << 1.0) can be ignored and can be treated as a linear relationship. By sequentially updating the control locus, the error can be ignored when the target operating point is reached.

Next, the relationship with the type of voltage control device will be described. First, when SVR (LRT) is used as the voltage control device, the SVR can be installed on the sending side of the two-point section, and ΔV (t) can be controlled by adjusting the sending voltage. When an SVC is used as the voltage control device, the SVC can be installed on the load side of the two-point section to control ΔQ (t). Similarly, the load device and the power generation device can be installed on the load side of the two-point section to control ΔP (t).

When SVR is used as a means for realizing the control amount ΔV, it is considered that the magnitude of ΔV is discrete and there is a time delay because the transformation ratio is changed by tap switching. When SVC is used as a means for realizing the control amount ΔQ, it is considered that the response speed is fast but the capacity is limited.

As a means for realizing the control amount ΔP, in order to utilize the power generation amount of the load device or the distributed power source, there is a method of prioritizing the device cutoff in order to reduce the power consumption of the load device. In addition, in order to reduce the amount of power generated by the distributed power source, there is a method of charging a storage battery or the like.

In this way, the present invention suppresses voltage fluctuations due to these effects even when there is a difference in response speed based on the operating principle of the voltage adjusting device, or when there is a time delay between the input of the measurement signal and the control output. , Has the effect of realizing stable voltage control.

For example, when SVR and SVC are combined as a voltage adjusting device, the response is different even if a control amount is given to both at the same time.

The difference between the two is the response speed, and since the SVR has a mechanical switching mechanism, it may take 10 seconds or more to switch. On the other hand, since the SVC has a switching circuit in the semiconductor element, the switching time is 1 second or less. SVR can be applied to long-period voltage fluctuations, and SVC can be applied to short-period voltage fluctuations due to PV power generation and the like.

The present invention includes means for distributing the calculated control amount based on the type, capacity, and response speed of the voltage adjusting device on the line.

In FIG. 6, the voltage optimization device 1 of the power system has been described. There are two types of control methods for controlling various parts of the power system by the voltage optimization device 1, one is centralized control and the other is autonomous control / remote control.

FIG. 14 is a flowchart showing a procedure for calculating the control amount when centralized control is performed. In the first processing step S141 of FIG. 14, input processing such as setting of a line section, input of voltage adjusting device characteristics, input of constraint conditions such as upper and lower limit voltages, and the like is executed. In the processing step S142, the measurement signal is input and stored.

In the processing step S143, the simultaneous solution of the voltage drop type is calculated and identified, in the processing step S144, the current operating point S1 is calculated using the measurement signal, and in the processing step S145, the input of the prediction signal is input as an option. Then, in the processing step S146, the target operating point S2 is set.

In the processing step S147, the control locus from the current operating point S1 to the target operating point S2 is calculated, in the processing step S148, the control amount is distributed to a plurality of voltage adjusting devices on the power system, and in the processing step S149, the control amount is distributed. Outputs control signals to individual voltage control devices.

In the centralized control, the measurement signal is input and the control amount is sequentially calculated. Therefore, the procedure is such that the processing steps S142 to S149 are repeated. Further, as the prediction signal of the processing step S145, for example, when the solar power generation amount prediction based on the weather prediction can be input, the voltage fluctuation due to the prediction signal can be considered. In the above procedure, geometrical relationships on the PQV solid such as the operating point, control locus, and upper and lower limit voltages can be used.

FIG. 15 is a flowchart showing a procedure for calculating a settling value used for settling in autonomous control or remote control. In the first processing step S151 of FIG. 15, input processing such as setting of a line section, input of voltage adjusting device characteristics, input of constraint conditions such as upper and lower limit voltages, and the like is executed. In the processing step S152, the measurement signal is input and stored.

In processing step S153, simultaneous solutions of voltage drop equations are calculated and identified, in processing step S154, the current operating point S1 is calculated using the measurement signal, and in processing step S155, line impedance is calculated. In the processing step S156, the settling value is set, and in the processing step S156, the settling value is output.

In this case, the set value used for autonomous control uses the measurement signal measured and accumulated in advance. In remote settling, in addition to the accumulated measurement signals, sequential measurement signals are input and used to calculate the settling value. In the case of remote settling, the settling value can be calculated in consideration of voltage fluctuations based on weather information and the like.

In the above procedure, geometrical relationships on the PQV solid such as the operating point, control locus, and upper and lower limit voltages can be used.

As the fifth embodiment, a system configuration example of the voltage optimization system of the electric power system will be described. FIG. 6 shows the configuration of the voltage optimization device 1 of the electric power system, but there are some application examples in applying this to the electric power system. In addition, there are some problems in system configuration for each individual application case.

For example, regarding data input, here, in order to input measurement signals at multiple locations on the line, sensor switches are placed on the line to measure voltage, current, force factor, etc., and via a transmission means. And input the measurement signal. Further, as the measuring instrument, it is assumed that the measurement signal collected by the measuring device provided in the voltage adjusting device can be similarly input via the transmission means.

In the present invention, it is not necessary that the timings of data sampling of a plurality of measuring instruments are synchronized. Further, the data transfer protocol of the measurement signal is not limited. For example, a polling method may be used in which a measurement signal is requested at an appropriate time interval or some trigger, and the measurement signal is transmitted as a response. The means of transmitting the measurement signal is not limited to power line carrier and optical fiber. Appropriate means such as wireless can be used.

In addition, there are autonomous control, remote control, and centralized control regarding the control method of the voltage adjusting device. In the case of autonomous control, the voltage optimization device 1 of the power system calculates a set value and transmits it to the autonomous control device side. In the case of remote control, the voltage optimization device 1 of the power system calculates the settling value and the control amount, and transmits this to the remote control device side. In the case of centralized control, the voltage optimization device 1 of the power system calculates the control amount and transmits it to the centralized control device side.

The main devices used as voltage control devices include SVR (LRT), SVC, load devices, power generation devices, storage batteries, and the like.

Further, as the main data transmission means, power line carrier, optical fiber, and wireless communication can be used.

16a and 16b show a system configuration of autonomous control and centralized control realized by combining the above means.

In the autonomous control of FIG. 16a, the voltage drop at the virtual load point is calculated using the preset set value and the measurement signal measured at the own end in the SVR control device 180 that controls the SVR 150 which is a voltage control device. Then, control is performed so as to compensate the voltage. In order to calculate the settling value for this purpose, the calculation procedure described in the examples of the present invention can be used.

In the centralized control of FIG. 16b, the measurement signal is collected by the measuring device 140 on the line, and the measurement signal is collected from the terminal 190 called the slave station to the server side (voltage optimizing device 1) via the communication line. The control amount is calculated by using the calculation procedure described in the embodiment of the present invention, and the control amount is transmitted to the control device via the communication path. The calculation procedure described in the examples of the present invention can be realized, for example, by the server (voltage optimizing device 1) in the figure.

Further, FIGS. 17a and 17b show a configuration method for calculating the control amount using the measurement signal. FIG. 17a shows a configuration at the time of sequential calculation using the captured measurement signals, and FIG. 17b shows a configuration in which the captured measurement signals are stored in a database and pre-calculated.

Although there is a difference in the handling of the input signal between FIGS. 17a and 17b, basically, the configuration in which the voltage drop equation is identified and the current operating point is calculated is shown here using the measurement signal. .. In calculating the identification of this voltage drop equation, a configuration in which the control amount is calculated using the sequentially input measurement signals (FIG. 17a) and a configuration in which the control amount is calculated using the measurement signals accumulated in advance (FIG. 17b). ) Is shown.

If there is a function to present the progress and results of the calculation to the parties concerned, the effect of fulfilling accountability can be obtained. Therefore, the present invention includes means for displaying the PQV solid and the control locus described above. The display means can be useful for grasping the system state by further making it possible to display the configuration of the power system, the content of the measurement signal, the past results, and the like.

As the sixth embodiment, voltage optimization using a voltage adjusting device will be described.

FIG. 18 shows a configuration when the voltage adjusting device is SVR. As shown in FIG. 18, the SVR used as a voltage adjusting device converts the voltage by setting the winding ratio between the primary side and the secondary side by tap switching. One of the tap setting methods is a method called LDC (Line Drop Composer), which is incorporated in the above-mentioned devices such as LRT and SVR. This estimates the voltage drop from the measurement signal (for example, Es) detected by the measuring device 140 installed at the node N1 at its own end to the load point (for example, node N2), and the voltage Er at the load point is appropriate. It is a method of controlling the tap so that it becomes a value. The parameter used to estimate this voltage drop is called the set value. The impedance (Z = R + jX) of the line 130 is set as one of the set values, and the voltage drop is estimated by multiplying the line impedance to the load point by the current flowing at its own end.

There are several methods for setting the virtual load point for calculating the line impedance using the present invention, and any of them may be used. These are places where a large-capacity load 170 or power generation equipment is connected, a virtual place where the load 170 and power generation equipment 160 are integrated, a place where a measuring device 140 is located, and a place where aggregates such as a microgrid are connected. And so on.

FIG. 19 shows a configuration when the voltage adjusting device is SVC. As shown in FIG. 19, the SVC (Static Var Compensator) uses a semiconductor element to switch between the magnitudes of inductance and capacitance to adjust the magnitude of reactive power. The voltage Er of the self-end N2 can be measured, and the output value of the reactive power Q can be adjusted so that the voltage Er becomes constant. The SVC has a high response speed but has a limited capacity of the output value of the ineffective power Q, and is therefore suitable for compensating for short-period voltage fluctuations caused by photovoltaic power generation.

By placing the current operating point S1 based on the measurement signal and the target operating point S2 for constant voltage control on the PQV solid, the magnitude of the required reactive power Q can be calculated.

When the generated power fluctuates due to weather conditions such as solar power generation, the presence or absence of deviation from the upper and lower voltage ranges can be determined on the PQV solid. Further, it is possible to calculate the control locus of the reactive power Q required to keep the operating point within the upper and lower limit voltage ranges.

When multiple SVCs are installed and each SVC controls the output of the invalid power Q based on the measurement signal at its own end, the operations of the multiple SVCs interfere with each other and become unstable (sometimes called hunting). May become. According to the present invention, by creating a control locus including a time parameter, it is possible to avoid vibration and stably control to a target operating point.

As the seventh embodiment, the calculation of the virtual load point will be described. In the autonomous control of the voltage adjusting device, the control amount required from the current voltage value to the target voltage value is calculated by using the measurement signals at its own end (or the primary side and the secondary side).

For example, in voltage adjusting devices such as SVR and LRT, a method for calculating a controlled variable called LDC (Line Drop Composer) is known. The LDC sets a virtual load point where load equipment and power generation equipment are concentrated, calculates the voltage drop amount by multiplying the secondary current by the line impedance to the load point, and compensates for the voltage at the load point. The control amount (tap value) is calculated as follows.

Parameters such as line impedance used in this calculation may be called set values. A form in which the settling value is set in advance to adjust the voltage is called autonomous control, and a form in which the settling value is set remotely according to the system state is called remote control. The present invention provides a method and an apparatus for calculating a set value (line impedance, etc.) of a voltage adjusting device by using a measurement signal of a distribution line.

The present invention calculates the line impedance Z = (R + jX) by identifying the voltage drop equation using the measurement signal. However, assuming the above equations (1) and (2), if the voltage drop equation between two points under the equations (1) and (2) is solved for the line impedance Z (R + jX), the following (12) The formula is obtained.

Further, when the active power P and the reactive power Q are measured on the sending side, the following equation (13) can be obtained by solving the voltage drop equation with respect to the line impedance Z = (R + jX). Here, too, the above-mentioned equations (1) and (2) are premised.

In the present invention, the line impedance Z = (R + jX) calculated using the measurement signal is defined as the line impedance up to the virtual load point. Assuming that the measurement signal (voltage V, current I, phase) can be collected, the unknown variables R and X of the line impedance, the voltage Er of the load point, and the phase difference angle are solved simultaneously. The present invention is characterized in that a simultaneous equation is created using measurement signals at at least 3 hours to obtain a solution, paying attention to the fact that the load amount or the power generation amount of the power system changes with the passage of time. Needless to say, when the measurement signal contains an error, a solution method such as a least squares method or an optimization calculation can be used.

Geometrically, Eq. (12) is three-dimensionally expressed with R and X and the load side voltage as the coordinate axes. Here, by describing the plurality of solids corresponding to the plurality of measurement signals, a common operating point of the plurality of solids can be obtained as an intersection. The line impedance (R and X) can be read from the coordinate values of this intersection.

Here, the procedure for calculating the settling value used for autonomous control and remote settling is as shown in FIG. Here, in the case of autonomous control, since the settling value is calculated using the measurement signal measured in advance and set in the voltage adjusting device, it is basic to go through the processing steps S151 to S156 once in FIG. It becomes a procedure. On the other hand, in the remote settling, since the settling value can be reset via the communication means, the procedure is such that the processing step S152 to the processing step S156 of FIG. 15 are repeatedly executed.

In the present invention, the calculated line impedance Z = (R + jX) up to the load point is used as a set value for autonomous control and remote control. For example, for the SVR, the line impedance Z = (R + jX) to the load point is calculated by the above procedure using the measurement signal on the sending side (secondary side of the SVR) collected by the measuring device built in the SVR. , The set value of the LDC described above. The LDC tap-controls the voltage at the virtually set load point so as to keep it constant. This set value may be sequentially updated in response to changes in the load, or may be set as a fixed value calculated based on a long-term measurement signal.

INDUSTRIAL APPLICABILITY The present invention has an effect that the workload can be reduced because the settling value can be calculated based on the measurement signals of the individual lines.

Although the features and embodiments of the present invention have been described using the PQV solid, the solid notation may be changed based on the variable of interest. As an example, a method of replacing the voltage axis of the PQV solid with the voltage on the sending side from the voltage on the load side will be shown.

The SVR and LRT adjust the sending voltage by switching the transformation ratio in order to control the voltage on the load side. Three-dimensional notation is used as a method for determining this sending voltage. The load point voltage Er in Eq. (3) is set to the target voltage, and the voltage Es on the sending side and the phase difference angle are three-dimensionally expressed as parameters. The voltage and PQ on the sending side are taken as coordinate axes, and the drawing result is shown in FIG. By placing the current operating point on this solid using the measurement signal, the sending voltage required to realize the target voltage of the load point can be read from the coordinate value (voltage axis) of the operating point. Here, if two solids in which the target voltage on the load side is set based on the upper limit voltage and the lower limit voltage of the line are created, the upper limit and the lower limit of the delivery voltage can be read from the operating point, respectively. If the sending voltage is set so as to fall within this range, the load side voltage can be kept within the upper and lower limit ranges.

The SVR and LRT have a function of selecting the ratio (transformation ratio) of the primary side voltage and the secondary side voltage by tap switching. Based on this relationship, the sending voltage can be converted into a transformation ratio and further converted into a tap value. In this way, the adjustment of the sending voltage can be realized by tap switching.

In remote settling and centralized control, a settling value or a control signal can be calculated based on a measurement signal collected via a communication means, and an instruction can be given every moment. Further, by referring to advance information such as weather forecast and demand forecast, control instructions of the voltage adjusting device may be issued before the system state changes.

The control procedure derived from the PQV solid described in the above embodiment or the solid notation in which the form is changed can be replaced with a numerical calculation. The control signal may be calculated by executing it as a numerical calculation without visually displaying the solid.

As shown in FIG. 21, the ninth embodiment of the present invention is characterized by comprising a verification means for determining the validity of the control amount or the settling value calculated in the present invention. The verification means calculates the system state by using a system analysis means such as state estimation or tidal current calculation. Then, a means for comparing and verifying the control amount or the settling value calculated by using the above-described embodiment of the present invention is prepared, and the result of the comparison and verification is output.

Further, the ninth embodiment of the present invention includes a display output that visualizes the relationship between the input and the result in an easy-to-understand manner. The system state is displayed using the PQV solid described above, and the operating points, constraints, control loci, etc. are superimposed and displayed on the solid. The configuration of the display screen is not limited. In addition, the system state calculated by the verification means and the comparative verification result can be displayed together. Further, by providing some kind of input means in addition to the display means, it is possible to input an operator's instruction, a comment, a work report, or the like and store the memory in association with the control output. This accumulated data can be utilized in offline processing and the like.

1: Voltage optimization device 2, 3: Input unit 4: Processing unit 5: Output unit 110: Distribution substation 120: Node 130: Line 140: Measuring device 150: SVR
160: Photovoltaic generator 170: Load device 180: Control device 190: Slave station 200: Communication line

Claims (39)

It is a voltage optimization device for the power system that is equipped with a voltage adjustment device that controls the voltage of the power system while connecting a distributed power source that provides renewable energy.
A first input unit that obtains a state quantity indicating the state of the power system from a measuring device installed in the power system, and a voltage drop equation of the power system are identified as PQV solids identified by equipotential circles using the state quantity. A voltage optimization device for a power system, characterized by comprising an identification unit to obtain and an output unit for determining an output to be given to the voltage adjusting device using the identified PQV solid. The voltage adjusting device for the power system according to claim 1.
The PQV solid is a voltage optimization device for a power system, characterized in that it is identified by an equipotential circle using active power, reactive power, and voltage as the state quantities. The voltage adjusting device for the power system according to claim 1 or 2.
The PQV solid obtained by the identification unit is provided with an operating point determining unit that determines a first operating point indicated by the state quantity of the power system, and the output unit uses the first operating point in the PQV solid. A voltage regulator for a power system that defines the output given to a voltage regulator. The voltage adjusting device for the power system according to claim 1 or 2.
With respect to the second input unit that gives a set value for the state of the power system and the PQV solid obtained by the identification unit, the first operating point indicated by the state quantity of the power system and the identified PQV solid The voltage adjusting device includes an operating point determining unit that defines an operating point indicated by the set value of the power system, and the output unit uses the first operating point and the second operating point in the PQV solid. A voltage regulator for a power system, characterized in that it determines the output given to the power system. The voltage adjusting device for the power system according to claim 4.
The output unit is a voltage optimization device for a power system, which obtains a control amount in the voltage adjusting device from the first operating point to the second operating point in the PQV solid. The voltage adjusting device for an electric power system according to any one of claims 1 to 5.
The identification unit describes the voltage drop equation of the section of the electric power system by the complex equation Es-Er = ZJ in which the sending voltage Es, the load side voltage Er, the line impedance Z, and the current J in the electric power system are complex variables, and is a measuring device. A voltage optimization device for a power system, characterized in that a voltage drop equation is identified by substituting the amount of state from the above into the voltage drop equation to create a simultaneous equation and solving an unknown variable. The voltage adjusting device for the power system according to claim 6.
The identification unit is a voltage optimization device for a power system, characterized in that the voltage drop equation can be calculated using a state quantity from a measuring device with the voltage phase difference angle as an unknown variable. The voltage adjusting device for an electric power system according to any one of claims 1 to 5.
When an error is included in the measurement signal of the state quantity at a plurality of times from the measuring device, the identification unit identifies the voltage drop equation by a calculation method considering the error. Chemical device. The voltage adjusting device for the power system according to claim 4 or 5.
The set value is a voltage optimization device for a power system, characterized in that it is a voltage condition of an upper limit voltage and a lower limit voltage in the power system. The voltage adjusting device for the power system according to claim 5.
The voltage optimization of the power system, characterized in that the control amount in the voltage adjusting device from the first operating point to the second operating point in the output unit is calculated as a control locus with time as a parameter. apparatus. The voltage adjusting device for the power system according to claim 5.
The control amount in the voltage adjusting device from the first operating point to the second operating point in the output unit is the second from the first operating point based on the response time of the connected voltage adjusting device. A voltage optimization device for a power system, which is characterized by calculating a control locus up to an operating point. The voltage adjusting device for an electric power system according to any one of claims 5, 10, and 11.
A voltage optimization device for a power system, characterized in that the control amount given from the output unit to the plurality of voltage adjusting devices is distributed according to the characteristics of the plurality of voltage adjusting devices. The voltage adjusting device for an electric power system according to any one of claims 1 to 12.
A voltage optimization device for a power system, wherein the state quantity indicating the state of the power system includes a state quantity obtained as a result of a state estimation calculation or a power flow calculation. The voltage adjusting device for an electric power system according to any one of claims 1 to 13.
The voltage optimization device includes a monitor device, and the voltage optimization device for a power system is characterized in that the PQV solid is displayed on the screen of the monitor device. The voltage adjusting device for an electric power system according to claim 14.
The PQV solid is drawn as coordinate points of active power, ineffective power, and voltage value for which a voltage drop equation is established in a space having active power, ineffective power, and voltage as coordinate axes. Equipment. The voltage adjusting device for the power system according to claim 14 or 15.
The PQV solid is a voltage optimization device for a power system, characterized in that it is drawn as an equal voltage circle and an operating point in a space whose coordinate axes are active power, reactive power, and voltage. The voltage adjusting device for the power system according to claim 2.
For the PQV solid, in the combination of active power, ineffective power, and voltage for which the voltage drop equation holds, when there is a combination of two voltage values in one active power and inactive power value, a high voltage value is selected. A voltage regulator for the power system, which is characterized by this. It is a voltage optimization method for a power system that is equipped with a voltage adjustment device that controls the voltage of the power system while connecting a distributed power source that provides renewable energy.
The state quantity indicating the state of the power system was obtained from the measuring device installed in the power system, and the voltage drop equation of the power system was obtained as a PQV solid identified by an equivoltage circle using the state quantity, and the identified product was obtained. A method for optimizing the voltage of a power system, which comprises determining an output to be given to the voltage adjusting device using a PQV solid. The method for optimizing the voltage of the power system according to claim 18.
A method for optimizing the voltage of a power system, wherein the PQV solid is identified by an equipotential circle using active power, reactive power, and voltage as the state quantities. The method for optimizing the voltage of the electric power system according to claim 18 or 19.
A power system characterized in that a first operating point indicated by the state quantity of the power system is determined for the PQV solid, and an output to be given to the voltage adjusting device is determined using the first operating point in the PQV solid. Voltage optimization method. The method for optimizing the voltage of the electric power system according to claim 18 or 19.
A set value for the state of the power system is given, and for the PQV solid, a first operating point indicated by the state amount of the power system and a second setting value of the power system in the identified PQV solid indicate. A method for optimizing the voltage of a power system, comprising defining an operating point and defining an output to be given to the voltage adjusting device using the first operating point and the second operating point in the PQV solid. The method for optimizing the voltage of the power system according to claim 21.
A method for optimizing the voltage of a power system, which comprises obtaining a control amount in the voltage adjusting device from the first operating point to the second operating point in the PQV solid. It is a voltage optimization method for a power system that is equipped with a voltage adjustment device that controls the voltage of the power system while connecting a distributed power source that provides renewable energy.
A state quantity indicating the state of the power system is obtained as a measurement signal from a measuring device installed in the power system, the first operating point of the power system is calculated using the measurement signal, and an equal voltage satisfying the constraint condition of the power system is satisfied. A circle is calculated, a second operating point is set in the region sandwiched by the equal voltage circle, a control locus from the first operating point to the second operating point is calculated, and the control locus is calculated based on the control locus. A method for optimizing the voltage of a power system, which is characterized by obtaining a controlled amount. The method for optimizing the voltage of the power system according to claim 23.
By moving, rotating, and extending the vector on the equivoltage circle that points to the control locus and the current operating point with time as a parameter until it matches the vector on the equivoltage circle that points to the target operating point, A voltage optimization method for a power system, characterized in that the end point is calculated as a control locus. It is a voltage optimization method for a power system that is equipped with a voltage adjustment device that controls the voltage of the power system while connecting a distributed power source that provides renewable energy.
A state quantity indicating the state of the power system is obtained as a measurement signal from the measuring equipment installed in the power system.
By substituting a plurality of measurement signals measured at different times into a voltage drop equation between two points in the power system, a first operating point is calculated as a combination of active power, ineffective power, and voltage, and the first operating point is calculated. A power system characterized in that the control amount from to the second operating point is calculated as a combination of active power, ineffective power, and voltage, and a coefficient (set value) for calculating the control amount is calculated. Voltage optimization method. The method for optimizing the voltage of an electric power system according to any one of claims 18 to 22.
A method for optimizing the voltage of a power system, wherein the output given to the voltage adjusting device is a set value of the voltage adjusting device. The method for optimizing the voltage of an electric power system according to any one of claims 18 to 22.
A method for optimizing the voltage of a power system, wherein the output given to the voltage adjusting device is the line impedance of a predetermined section of the power system. The method for optimizing the voltage of the electric power system according to claim 27.
A method for optimizing the voltage of a power system, which comprises substituting a plurality of measurement signals measured at different times from the power system into a voltage drop equation of the power system to obtain a line impedance to a virtual load point. The method for optimizing the voltage of the electric power system according to claim 27.
Obtain the measurement signal on the sending side for the two points set in the power system, and substitute multiple measurement signals measured at different times into the voltage drop equation of the power system to obtain the line impedance to the virtual load point. A method for optimizing the voltage of an electric power system. The voltage adjusting device for an electric power system according to any one of claims 1 to 17.
A voltage adjusting device for a power system, which comprises means for verifying the operation of the power system by operating the voltage adjusting device with an output given to the voltage adjusting device. It is a voltage optimization system for the power system that connects distributed power sources that provide renewable energy.
It is equipped with a voltage regulator that is installed in the power system and controls the voltage of the power system, and a voltage regulator that supplies output to the voltage regulator.
The voltage optimization device uses a first input unit that obtains a state quantity indicating the state of the power system from a measuring device installed in the power system, and a voltage drop type of the power system, and an equal voltage using the state quantity. A voltage optimization system for a power system, comprising: an identification unit obtained as a PQV solid identified by a circle, and an output unit that determines an output to be given to the voltage adjusting device using the identified PQV solid. The voltage optimization system for the power system according to claim 31.
The PQV solid is a voltage optimization system for a power system, characterized in that it is identified by an equal voltage circle using active power, reactive power, and voltage as the state quantities. The voltage optimization system for the power system according to claim 31 or 32.
The PQV solid obtained by the identification unit is provided with an operating point determining unit that determines a first operating point indicated by the state quantity of the power system, and the output unit uses the first operating point in the PQV solid. A voltage optimization system for a power system that defines the output given to a voltage regulator. The voltage optimization system for the power system according to claim 31 or 32.
With respect to the second input unit that gives a set value for the state of the power system and the PQV solid obtained by the identification unit, the first operating point indicated by the state quantity of the power system and the identified PQV solid The voltage adjusting device includes an operating point determining unit that defines an operating point indicated by the set value of the power system, and the output unit uses the first operating point and the second operating point in the PQV solid. A voltage optimization system for the power system, which is characterized by determining the output given to the power system. The voltage optimization system for the power system according to claim 34.
The output unit is a voltage optimization system for a power system, characterized in that a control amount in the voltage adjusting device from the first operating point to the second operating point in the PQV solid is obtained. The voltage optimization system for an electric power system according to any one of claims 31 to 35.
A voltage optimization system for a power system, wherein the output given to the voltage adjustment device by the voltage adjustment device is an impedance between two points of the power system. The voltage optimization system for an electric power system according to any one of claims 31 to 35.
A voltage optimization system for a power system, characterized in that an output given to the voltage adjusting device by the voltage adjusting device is a controlled amount of the voltage adjusting device. The voltage optimization system for an electric power system according to any one of claims 31 to 35.
A voltage optimization system for an electric power system, characterized in that an output given to the voltage adjusting device by the voltage adjusting device is a set value of the voltage adjusting device. The voltage optimization system for an electric power system according to any one of claims 31 to 35.
A voltage optimization system for a power system, wherein the voltage adjusting device installed in the power system is at least one of a substation LRT, SVR, TVR, SVC, SC, and ShR.

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