KR20210030124A - Active Distribution Energy Management System of Integrated PV ESS System Based on Smart Inverter Functions - Google Patents

Abstract

The present invention relates to a smart inverter-based active distribution energy management system (EMS) of a solar ESS integrated system and a control method thereof, which can create a profit due to charging and discharging by using a renewable energy certificate (REC) weighting factor and making a distribution system stable by applying an active EMS algorithm in the solar ESS integrated system. The present invention comprises: a power price information determination unit performing an INV5 function of a smart inverter to check power price information; a system voltage maintenance determination unit measuring an interconnection point voltage (V) of the solar ESS integrated system to determine whether the measured voltage is maintained within a lower limit (V_min) and an upper limit (V_max) of a system voltage; an ESS full charging determination unit determining whether the ESS of the solar ESS integrated system is fully charged; a congestion reference power consumption unit consuming solar power based on line congestion when the ESS is fully charged; a voltage stabilizing unit stabilizing voltage using the solar inverter in the case of being deviated from a system voltage maintenance range; and a reactive power output control unit performing a VV11 function of calculating available maximum reactive power (Q_avail) and outputting reactive power according to a system interconnection point voltage.

Description

Active Distribution Energy Management System of Integrated PV ESS System Based on Smart Inverter Functions {Active Distribution Energy Management System of Integrated PV ESS System Based on Smart Inverter Functions}

The present invention relates to a solar ESS integrated system, and specifically, a solar power distribution system stabilization by applying an active EMS (Energy Management System) algorithm and generating revenue by charging and discharging using a REC (Renewable Energy Certificate) weight. It relates to a smart inverter-based active distribution EMS of an optical ESS integrated system and a control method thereof.

In general, ESS (Energy storage system) refers to a storage device that stores excessively produced power or irregularly produced new and renewable energy in a power plant and transmits it when power is temporarily insufficient.

Specifically, ESS refers to a system that stores electricity in the electric power system to supply energy when and where it is needed. In other words, it is an aggregate composed of storage in which a system is integrated into a single product, like a conventional secondary battery.

The importance of ESS is emerging as an essential device that stores unstable power generation energy during photovoltaic power generation, which is a rapidly growing new and renewable energy, and then stably supplies it back to the power system when needed.

If there is no ESS, serious problems such as sudden power failure may occur in the power system due to unstable power supply that relies on solar power. Therefore, storage is emerging as a very important field in this environment.

These ESSs are installed and used in power generation, transmission and distribution, and customers in the power system, and frequency regulation, generator output stabilization using renewable energy, peak shaving, load leveling, emergency It is used for functions such as power supply.

1 is a graph showing a voltage-reactive power droop control and a voltage-active power droop control for stabilizing voltage of a distribution line according to the prior art.

In the case of the conventional smart inverter technology, a lot of research has been conducted in terms of voltage stabilization of distribution lines using a solar inverter. Representatively, there are VV11 function (voltage-reactive power droop control) and VW51 (voltage-active power droop control).

However, the conventional techniques have not been able to propose a plan for stabilization of the distribution system by simultaneously utilizing sunlight and ESS. In addition, since various smart inverter functions cannot be utilized, an efficient management method according to changes in various system conditions has not been proposed.

Therefore, there is a need to develop a new technology to efficiently solve problems such as overloading of distribution lines due to an increase in the acceptance rate of renewable energy by using the smart inverter function of the solar ESS integrated system.

Korean Patent Registration No. 10-1871237 Korean Patent Registration No. 10-1964740 Korean Patent Registration No. 10-1988485

The present invention is to increase the usability of the solar ESS integrated system, to generate revenue by charging and discharging using REC (Renewable Energy Certificate) weights, and to stabilize the distribution system by applying an active EMS (Energy Management System) algorithm. The purpose of this is to provide a smart inverter-based active distribution EMS of a solar ESS integrated system and a control method thereof.

The present invention uses a smart inverter function of a solar ESS integrated system to efficiently solve problems such as overloading of distribution lines due to an increase in the acceptance rate of renewable energy, and a smart inverter-based active distribution EMS of a solar ESS integrated system and its Its purpose is to provide a control method.

The present invention proposes to limit the maximum amount of power of the line current in consideration of the output power, line power, and load of the generator linkage point, and prevents the line congestion section, a smart inverter-based active distribution EMS and its control of a solar ESS integrated system. Its purpose is to provide a method.

The present invention is a smart inverter-based active distribution of a solar ESS integrated system that enables efficient adjustment of voltage by controlling the active/reactive power of a solar ESS integrated system so that the common connection point voltage and line voltage do not exceed the constant voltage standard. It is an object to provide an EMS and a control method thereof.

The present invention provides a smart inverter-based active distribution EMS of a solar ESS integrated system and a control method thereof that enables efficient distribution system stabilization by allowing the solar ESS integrated system to mitigate this when voltage fluctuations in the distribution system. There is a purpose.

The present invention makes it possible to connect distributed power sources with a capacity of 10MW or more of distribution lines, and when a congested distribution line occurs, the power generation amount of the distributed power is stored in the ESS to facilitate the stabilization of the distribution system.The smart inverter-based active distribution EMS of the solar ESS integrated system And to provide a method for controlling the same.

The present invention is a smart inverter-based active distribution of a solar ESS integrated system that enables distributed power to actively participate in distribution system operation through efficient arrangement of smart inverter functions, and to promote profit creation by reflecting power price information. It is an object to provide an EMS and a control method thereof.

Other objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

The smart inverter-based active distribution EMS of the solar ESS integrated system according to the present invention to achieve the above object, in order to control charging in the smart inverter-based active distribution EMS of the solar ESS integrated system, the INV5 function of the smart inverter. Power price information determination unit to determine power price information by performing; System voltage to determine whether the system voltage is maintained within the lower limit (V _min ) and upper limit ( V _max ) of the system voltage by measuring the connection point voltage (V) of the solar ESS integrated system Maintenance determination unit; ESS buffer determination unit that determines whether the ESS of the solar ESS integrated system is fully charged; reduces power generation or reduces power generation by performing INV2 function based on line congestion during ESS charging Congestion standard power consumption unit using generated power for load consumption; Voltage stabilization unit that performs voltage stabilization using a solar inverter when the system voltage is out of range; Calculates the maximum reactive power (Q _avail ) that can be supplied and the system And a reactive power output control unit that performs a VV11 function of outputting reactive power according to the connection point voltage.

The smart inverter-based active distribution EMS of the solar ESS integrated system according to the present invention for achieving other purposes performs the INV5 function of the smart inverter in order to control the discharge in the smart inverter-based active distribution EMS of the solar ESS integrated system. Power price information determination unit that determines power price information; Distribution line congestion level determination unit that determines the congestion level of the distribution line before discharging the stored power of the ESS; Compensation for reactive power by performing VV11 mode when the junction voltage is out of the limit value A voltage stabilization unit that performs voltage stabilization by performing an INV2 function; a power calculation unit that calculates the power that can be discharged so as not to exceed 10MW, which is the capacity of a domestic distribution line; a connection point before discharging the power charged in the ESS It characterized in that it comprises a; voltage stability determination and discharge control unit for controlling the discharge by determining the voltage stability of the.

Here, the INV5 function is to determine whether the distributed power with storage capacity using the price determination signal determines whether the ESS is charged/discharged and the charging/discharging ratio, and the INV2 function limits the distributed power output at the system connection point and distributed When the power generation exceeds the limit, the output is reduced or the extra generation is stored in the energy storage device, and the VV11 function produces reactive power (VarAval) according to the connection point voltage (VRef) without fluctuations in the active power output, and the inverter It is characterized in that the numerical value of the reactive power that can be supplied in consideration of the capacity of is presented as a percentage, and as the connection point voltage increases, the negative reactive power is output, and as the connection point voltage decreases, the positive reactive power is output.

In order to control charging in the smart inverter-based active distribution EMS of the solar ESS integrated system according to the present invention to achieve another object, the power price information determination unit Determining power price information at; determining whether the system voltage is maintained within a lower limit value ( V _min ) and an upper limit value ( V _max ) by measuring the connection point voltage (V) of the solar ESS integrated system in the system voltage maintenance determination unit; Determining whether the ESS is fully charged by the ESS buffer determination unit; Consumption of solar power generated by the power consumption unit based on the congestion level when the ESS is fully charged; Solar light when the voltage stabilization unit exceeds the system voltage maintenance range And performing voltage stabilization using an inverter.

Here, the step of determining the power price information is characterized in that the distributed power supply having the storage capacity using the price determination signal is performed through the INV5 function of the smart inverter that determines whether the ESS is charged/discharged and the charge/discharge ratio. .

And if the grid voltage maintenance determination part determines that the grid voltage maintenance range is satisfied, the INV4 function is performed to charge the solar power generation power to the ESS, and the INV4 function allows the distributed power supply with storage capacity to participate in the increase or decrease of energy production. The request command is characterized in that it consists of a percentage of the maximum output of the energy storage device.

In addition, the power consumption unit based on the congestion level reduces the generation power by performing the INV2 function when active power exceeds 10MW, which is the general line capacity of domestic distribution based on the line congestion, and otherwise uses the solar power generation for load consumption. Characterized in that.

In addition, the INV2 function limits the output of distributed power at the system connection point, and when the amount of distributed power generation exceeds the limit, it is a function to reduce the output amount or to store the extra generation amount in the energy storage device.

And in the step of performing voltage stabilization, voltage stabilization is performed by the reactive power output of the solar inverter, and is possible only when the solar active power output ( P _pv ) is smaller than the capacity (S _inv ) of the solar inverter, and P _pv When is not smaller than S _inv , the active power of the solar power is reduced by performing the INV2 function, and it is characterized by making a margin for outputting the reactive power to the solar inverter.

And P _pv Calculates the maximum reactive power (Q _avail ) that can be supplied in consideration of and S _inv , performs the VV11 function that outputs reactive power according to the voltage of the grid connection point, and outputs the maximum reactive power that can be supplied when performing the VV11 function through Q _{avail calculation.} It is characterized by being limited.

In addition, the VV11 function produces reactive power (VarAval) according to the connection point voltage (VRef) without fluctuations in the active power output, and presents the number of reactive power that can be supplied in percent based on the capacity of the inverter. It is characterized by outputting negative reactive power and outputting positive reactive power as the connection point voltage decreases.

In order to control discharging in the smart inverter-based active distribution EMS of the solar ESS integrated system according to the present invention to achieve another object, the power price information is determined to control the discharge in the smart inverter-based active distribution EMS of the solar ESS integrated system. Determining power price information by the unit; determining the degree of congestion of the distribution line before discharging the stored power in the ESS by the distribution line congestion level determination unit; when the distribution line is congested, the voltage stabilization unit stabilizes the voltage at the connection point. When performing the function and the distribution line is not congested, calculating the maximum amount of power that can be discharged based on the capacity of the distribution line in the power calculation unit; before discharging the electric power charged in the ESS by the voltage stability determination and discharging control unit It characterized in that it comprises a; determining the voltage stability of the connection point to control the discharge.

Here, the power when the distributed power with the storage capability performs INV5, which determines whether the ESS is charged/discharged and the rate of charge/discharge by using the price determination signal in the power price information determination unit, and sells the charged power in the ESS. It characterized in that it acquires price information.

And when the distribution line is not congested, in the step of calculating the maximum amount of power that can be discharged based on the capacity of the distribution line in the power calculation unit, the maximum amount of power that can be discharged is calculated using the INV2 function, and the INV2 function is It is characterized in that it is a function to limit the output of distributed power at the point of connection of the system, and to reduce the amount of power generated when the amount of distributed power generation exceeds the limit value or to store the excess amount of power in the energy storage device.

In addition, when the distribution line is congested, the voltage stabilization unit performs the voltage stabilization function of the connection point, and when the voltage of the connection point exceeds the limit, VV11 mode is performed to compensate for reactive power to contribute to voltage stabilization. It is done.

In addition, the VV11 function produces reactive power (VarAval) according to the connection point voltage (VRef) without fluctuations in the active power output, and presents the number of reactive power that can be supplied as a percentage by considering the capacity of the inverter. It is characterized by outputting negative reactive power and outputting positive reactive power as the connection point voltage decreases.

In addition, the voltage stability determination and discharge control unit performs the VW51 function when the connection point voltage is within the limit value to perform discharge according to the connection point voltage, and when the connection point voltage is out of the limit value, it executes WP41 mode to perform active power and reactive power. It is characterized in that voltage stabilization and ESS discharge are performed at the same time by outputting at the same time.

In addition, the VW51 function adjusts the amount of active power output according to the state of the grid connection point voltage. As the grid connection point voltage increases, the amount of active power output decreases proportionally, and WP41 is based on the active power output from the grid connection point. As a function to stabilize the voltage by adjusting the power factor, the WP41 is characterized by inputting motion in the form of a curve.

As described above, the smart inverter-based active distribution EMS of the solar ESS integrated system according to the present invention and a control method thereof have the following effects.

First, the distribution system can be stabilized by generating revenue by charging and discharging using REC (Renewable Energy Certificate) weights and applying an active EMS (Energy Management System) algorithm.

Second, by using the smart inverter function of the solar ESS integrated system, it is possible to efficiently solve problems such as overloading of distribution lines due to an increase in the acceptance rate of renewable energy.

Third, considering the output power, line power, and load of the generator connection point, it is suggested to limit the maximum power amount of the line current and prevent the line congestion section.

Fourth, the active/reactive power of the solar ESS integrated system is controlled so that the voltage of the common connection point and the line voltage do not exceed the constant voltage standard so that the voltage can be efficiently adjusted.

Fifth, in the case of voltage fluctuations in the distribution system, the solar ESS integrated system can mitigate this so that efficient distribution system stabilization is possible.

Sixth, it is possible to connect distributed power sources of 10MW or more, which is the capacity of a distribution line, and when a congested distribution line occurs, the power generation amount of the distributed power is stored in the ESS to be advantageous for stabilizing the distribution system.

Seventh, through the efficient arrangement of smart inverter functions, distributed power can be actively involved in distribution system operation, and power price information can be reflected to promote profitability.

1 is a graph showing voltage-reactive power droop control and voltage-active power droop control for voltage stabilization of a distribution line according to the prior art.
Figure 2a is a characteristic graph showing the smart inverter function of the solar ESS integrated system
Figure 2b is a configuration diagram showing an example of an actual domestic distribution system (solar ESS integrated system 9MW linkage)
3 is a configuration diagram of a controller using the INV2 function
4 is a graph of the active power output limitation characteristic of the INV2 function
5 is a configuration diagram of a controller using the INV4 function
6 is a graph of the result of ESS output control of INV4 function
7 is a configuration diagram of ESS charge/discharge control using INV5
Figure 8 is a graph of the ESS charging characteristics reflecting the (left) REC incentive time signal and (right) price signal showing the INV5 function of the solar ESS integrated system
9 is a reactive power-voltage control characteristic graph using the VV11 function
10A to 10D show the reactive power compensation result by applying the VV11 function (a) load variation (b) control signal (c) junction voltage (d) reactive power output graph
11 is a voltage-active power control graph of VW51
12A to 12D are VW51 function simulation results (a) voltage reference signal (b) VW51 mode at minimum load (c) active power output (d) VW51 mode graph at maximum load
13 is a graph of active power-power factor control as a function of WP41
14A to 14D are WP41 function simulation results (a) PV ESS integrated system active power fluctuations (b) WP41 mode operation (c) Power factor signal (d) Reactive power output graph
Figure 15a is a configuration diagram of a smart inverter-based active distribution EMS (charging) of the solar ESS integrated system according to the present invention
15B is a flow chart for controlling a smart inverter-based active distribution EMS (charging) of the solar ESS integrated system according to the present invention
Figure 16a is a smart inverter-based active distribution EMS (discharge) configuration of the solar ESS integrated system according to the present invention
Figure 16b is a flow chart for a smart inverter-based active distribution EMS (discharge) control of the solar ESS integrated system according to the present invention

Hereinafter, a detailed description will be given of a preferred embodiment of a smart inverter-based active distribution EMS and a control method thereof of a solar ESS integrated system according to the present invention.

Features and advantages of the smart inverter-based active distribution EMS of the solar ESS integrated system according to the present invention and the control method thereof will be apparent through detailed description of each embodiment below.

Figure 2a is a characteristic graph showing the smart inverter function of the solar ESS integrated system, Figure 2b is a configuration diagram showing an example of a domestic actual distribution system (solar ESS integrated system 9MW linkage).

As the domestic renewable energy acceptance rate increases, the overload phenomenon of distribution lines is increasing, and the present invention is to solve this by utilizing a solar ESS integrated system.

The smart inverter-based active distribution EMS and its control method of the solar ESS integrated system according to the present invention generate revenue by charging and discharging using Renewable Energy Certificate (REC) weights, and distribution by applying an active EMS (Energy Management System) algorithm. System stabilization is possible.

The solar ESS integrated system has the characteristic of being connected to the system by sharing the connection point of the solar power and the energy storage device (ESS), and the solar power output can be stored in the ESS so that the distribution line overload at the connection point does not occur. . In order to perform such control, the smart inverter function of the solar ESS integrated system is required.

International standard IEC 61850-90-7 proposes a standard of smart inverter function to improve the stability of the distribution system for a converter-based distributed power supply, and the present invention finally applies the functions to a solar ESS integrated system. Management System) algorithm.

The smart inverter functions applied to the present invention are the same as in Fig. 2a, and the function is basically simulated by linking the solar ESS integrated system to the domestic actual system of 2b in a 9MW class.

In the smart inverter-based active distribution EMS and its control method of the solar ESS integrated system according to the present invention, after analyzing the effects of each of the smart inverter functions, a distribution EMS algorithm is constructed based on the corresponding functions.

First, the INV1 (connect/disconnect from grid) function is a function that connects or disconnects the distributed power system at the point of connection of the grid.In order to prevent sudden voltage fluctuations when reconnecting after the loss of distributed power, the limit for the slope of the increase in active power is To be able to set it up.

And the INV2 (adjust maximum generation level up/down) function is as follows.

3 is a configuration diagram of a controller using the INV2 function, and FIG. 4 is a graph showing the limiting characteristics of active power output of the INV2 function.

The INV2 function limits the output of distributed power at the system connection point, and when the amount of distributed power generation exceeds the limit, it is a function to reduce the output amount or to store the extra generation amount in the energy storage device.

A control model to be applied to the solar ESS integrated system can be configured as shown in FIG. 3, and extra power is stored in the ESS in consideration of the output limit. When applying the INV2 function, it is possible to limit the amount of solar power output as shown in Fig. 4 (solar power output 9MW, output limit 7MW, ESS charging 2MW).

And the INV3 (adjust power factor) function is a smart inverter function that changes the fixed power factor of the inverter through a setpoint. In the case of solar ESS integrated system, it is possible to change the power factor through the command value, and accordingly, the output of active power and reactive power can be changed.

And the INV4 (request active power (charge or discharge storage) function) is as follows.

5 is a configuration diagram of a controller using the INV4 function, and FIG. 6 is a graph of the result of ESS output control of the INV4 function.

The INV4 function allows the distributed power supply with storage capacity to participate in the increase or decrease of energy production, and the request command is made as a percentage of the maximum output of the energy storage device.

5 is a control model to which the INV4 function is applied, and when the load is greater than the amount of power that can be supplied from the system, insufficient power is reinforced through the ESS.

6 shows the operation of the INV4 function in the solar ESS integrated system.

And the INV5 (pricing signal for charge/discharge action) function will be described as follows.

7 is a configuration diagram of ESS charging and discharging control using INV5, and FIG. 8 is a graph of ESS charging characteristics reflecting (left) REC incentive time signal and (right) price signal showing INV5 function of a solar ESS integrated system.

The INV5 function uses the price determination signal to determine whether the distributed power supply with storage capacity determines whether or not the ESS is charged, discharged, and the rate of charging and discharging, and Fig. 7 sets the ESS charging reference signal according to the price signal in the solar ESS integrated system. It shows what to do.

FIG. 8 is a result of ESS charging and discharging reflecting REC price information for a solar ESS integrated system. As a result, a signal of a REC incentive system is received and electric power is charged.

And VV11 (available vars support with no impact on watts) function is described as follows.

9 is a graph of reactive power-voltage control characteristics using the VV11 function, and FIGS. 10A to 10D are results of compensation of reactive power applying the VV11 function (a) load variation (b) control signal (c) junction voltage (d) invalidity. This is the power output graph.

The VV11 function produces reactive power (VarAval) according to the connection point voltage (VRef) without fluctuations in the active power output, and presents the number of reactive power that can be supplied in percent by considering the capacity of the inverter.

Reactive power-voltage control corresponding to the VV11 function is shown in FIG. 9, and as the connection point voltage increases, negative reactive power is output, and as the connection point voltage decreases, positive reactive power is output.

In IEC 61850-90-7, the values of P1, P2, P3, and P4 shown in FIGS. 10A to 10D are specified, and Table 1 is an operation point applied to a solar ESS integrated system in an embodiment of the present invention.

Table 1 is an example of reactive power compensation applying the VV11 function.

10A to 10D are results of performing the VV11 function of the solar ESS integrated system, and the VV11 function operation signal as shown in (b) is generated in response to the load fluctuation situation as shown in (a).

The voltage and reactive power in (c) and (d) when the VV11 function is applied (blue line) and when the VV11 function is not applied (red line) is shown in (c) and (d), and when the VV11 function is not applied, the connection point voltage rapidly decreases as the load increases. In case of applying VV11, it maintains a certain range of voltage as reactive power output according to the voltage of the connection point.

And the VW51 (generating by voltage) function is as follows.

11 is a voltage-active power control graph of VW51, and FIGS. 12A to 12D are VW51 function simulation results (a) voltage reference signal (b) VW51 mode at minimum load (c) active power output (d) VW51 at maximum load This is a mode graph.

The VW51 function is a function of adjusting the amount of active power output according to the state of the grid connection point voltage. As shown in FIG. 11, as the grid connection point voltage increases, the amount of active power output decreases proportionally.

The shape of the curve of the VW51 function can be changed by reflecting the load state, and the results of reflecting the minimum load and the maximum load of the distribution line (FIG. 2B) simulated in the embodiment of the present invention are shown in Table 2.

Table 2 shows the (left) minimum load and (right) maximum load as examples of VW51 function application.

12A to 12D are results of performing the VW51 function of the solar ESS integrated system, and the active power output as in (c) is possible with respect to the voltage fluctuations as in (a).

12(b) and (d) show the active power output reflecting the voltage of (a) at the maximum load and the minimum load, respectively. In the case of the maximum load, relatively more active power can be output.

And the functions of WP41 and WP42 (feed-in power controls power factor) are as follows.

13 is an active power-power factor control graph that is a WP41 function, and FIGS. 14A to 14D are WP41 function simulation results (a) fluctuations in active power of the solar ESS integrated system (b) WP41 mode operation (c) power factor signal (d) reactive power This is the output graph.

The WP41 and WP42 stabilize the voltage by adjusting the power factor according to the active power output from the grid connection point. WP41 inputs motion in the form of a curve, and WP42 inputs motion in the form of an array.

13 shows that the function of WP41 is applied, and when the active power input to the system changes, the power factor of the solar ESS integrated system is adjusted to contribute to system voltage stabilization.

Table 3 shows the operating points of the WP41 function, and determines the magnitude of the power factor and its sign according to the active power output of the solar ESS integrated system.

14A to 14D are the results of applying WP41 to the solar ESS integrated system, and the change in the power factor as in (c) for the active power output (9MW → 8MW → 6MW → 3MW) of the solar ESS integrated system as shown in (a). Looks.

14B is a graph of the WP41 corresponding to the active power output of the solar ESS integrated system of (a), and (d) is a result showing the change of the reactive power output according to the power factor change of the integrated system of (c).

The smart inverter-based active distribution EMS of the solar ESS integrated system according to the present invention using the smart inverter function described above and a control method thereof will be described in detail as follows.

As part of expanding the renewable energy business, the government is imposing a Renewable Energy Certificate (REC) weight of 5.0 on power produced by combining ESS with solar power.

Due to the grant of REC 5.0, solar operators can expect high profits, and in one embodiment of the present invention, the ESS includes charging power generated from solar power from 10 am to 4 pm when REC 5.0 is charged. do.

In addition to generating revenue through charging and discharging using REC weights, the active EMS of the present invention includes the following distribution system stabilization technology.

First, it includes a configuration that proposes limiting the maximum power amount of the line current in consideration of the output power, line power, and load of the generator connection point and prevents the line congestion section.

And it includes a configuration that adjusts the voltage by controlling the active/reactive power of the solar ESS integrated system so that the common connection point voltage and line voltage do not exceed the constant voltage standard.

In addition, when the voltage of the distribution system changes, the solar ESS integrated system includes a configuration to mitigate this.

Figure 15a is a configuration diagram of a smart inverter-based active distribution EMS (charging) of the solar ESS integrated system according to the present invention.

The smart inverter-based active distribution EMS of the solar ESS integrated system according to the present invention is a configuration for controlling charging, and the power price information determination unit 10 to determine the power price information by performing the INV5 function of the smart inverter, and the sun. The grid voltage maintenance determination unit (11) that measures the connection point voltage ( V ) of the optical ESS integrated system to determine whether the system voltage is maintained within the lower limit (V _min ) and the upper limit ( V _max ), and the ESS of the solar ESS integrated system An ESS buffer determination unit 12 that determines whether the ESS is fully charged, a power consumption unit 13 based on congestion that consumes solar power generated based on line congestion during ESS charging, and the system A voltage stabilization unit 14 that performs voltage stabilization using a solar inverter when the voltage is out of the range, and VV11 that calculates the maximum reactive power (Q _avail ) that can be supplied and outputs reactive power according to the voltage of the grid connection point. It includes a reactive power output control unit 15 that performs a function.

15B is a flow chart for controlling a smart inverter-based active distribution EMS (charging) of the solar ESS integrated system according to the present invention.

When REC (Renewable Energy Certificate) weight is applied, it shows the charging algorithm from 10 am to 4 pm.

First, the power price information determination unit 10 performs the step of determining the power price information by performing INV5 among the smart inverter functions, and when the solar power output power is stored in the ESS, it determines the time at which the REC weight can be received. (S1501)

Subsequently, the grid voltage maintenance determination unit 11 measures the connection point voltage (V ) of the solar ESS integrated system to determine whether the grid voltage is maintained within the lower limit value (V _min ) and the upper limit value ( V _{max ).} S1502)

When the grid voltage maintenance range is satisfied, the solar power generated by the INV4 function is charged to the ESS.

Then, the ESS buffer determination unit 12 performs the step of determining whether the ESS of the solar ESS integrated system is fully charged. (S1503) When the ESS is fully charged, the step moves to the step of consuming solar power generation. .

Subsequently, the power consumption unit 13 based on the congestion level performs a step of consuming the generated power of the solar light when the ESS is fully charged (S1504).

In case the distribution line is congested in consideration of line congestion (i.e., when active power of 10MW or more, which is the general distribution line capacity in Korea), reduces power generation by performing INV2 function, and when the line is not congested, solar power The generated power is used for load consumption.

In addition, when the voltage stabilization unit 14 exceeds the grid voltage maintenance range, a voltage stabilization step is performed using a solar inverter (S1505).

Voltage stabilization is performed by the reactive power output of the solar inverter, and is possible only when the solar active power output ( P _pv ) is smaller than the capacity (S _inv ) of the solar inverter, and P _pv If is not less than S _inv , the active power of solar power is reduced by performing the INV2 function, and finally, it makes a margin to output reactive power to the solar power inverter.

P _pv It calculates the maximum reactive power (Q _avail ) that can be supplied by considering and S _inv , and performs the VV11 function that outputs reactive power according to the voltage of the system connection point. Through the Q _avail calculation, the maximum reactive power output that can be supplied when performing the VV11 function is limited.

Figure 16a is a configuration diagram of a smart inverter-based active distribution EMS (discharge) of the solar ESS integrated system according to the present invention.

The smart inverter-based active distribution EMS of the solar ESS integrated system according to the present invention is a configuration for controlling discharge, and the power price information determination unit 20 that determines the power price information by performing the INV5 function of the smart inverter, and the ESS A distribution line congestion level determination unit 21 that determines the level of congestion of the distribution line before discharging the stored power of and when the connection point voltage exceeds the limit value, voltage stabilization is performed by compensating for reactive power by performing VV11 mode. The unit 22, the power calculation unit 23, which calculates the power that can be discharged so as not to exceed 10MW, the capacity of the domestic distribution line by performing the INV2 function, and the connection point before discharging the electric power charged in the ESS. It includes a voltage stability determination and discharge control unit 24 for controlling the discharge by determining the voltage stability.

16B is a flow chart for controlling an active power distribution EMS (discharge) based on a smart inverter of the solar ESS integrated system according to the present invention.

It shows the discharge algorithm from 4 pm to 10 am the next day when the REC (Renewable Energy Certificate) weight is not applied.

First, the power price information determination unit 20 performs the step of determining the power price information by performing INV5 among the smart inverter functions to obtain power price information when the power charged in the ESS is sold (S1601).

Then, before discharging the stored power of the ESS in the distribution line congestion level determining unit 21, a step of determining the congestion level of the distribution line is performed (S1602).

Here, when the distribution line is congested, since power cannot be sent to the distribution line, the voltage stabilization unit 22 performs a voltage stabilization function of the connection point (S1603), and when the distribution line is not congested, the power calculation unit 23 ), the maximum amount of power that can be discharged is calculated using the INV2 function in consideration of the distribution line capacity (S1604).

In step (S1603), when the distribution line is congested, the EMS performs a voltage stabilization function, and when the connection point voltage exceeds the limit value, the VV11 mode is performed to compensate for reactive power, thereby contributing to voltage stabilization.

Step (S1604) is to perform the INV2 function to calculate the power that can be discharged so as not to exceed 10MW, which is the capacity of the domestic distribution line.

Subsequently, the voltage stability determination and discharging control unit 24 performs a step of determining the voltage stability of the connection point before discharging the electric power charged in the ESS (S1605).

Here, when the voltage of the linkage point is within the limit, the VW51 function is performed to discharge according to the voltage of the linkage point. If the voltage of the linkage point is out of the limit, the WP41 mode is performed to output active and reactive power at the same time to stabilize the voltage. Simultaneously perform ESS discharge.

The smart inverter-based active distribution EMS and its control method of the solar ESS integrated system according to the present invention described above are revenue generation and active EMS (Energy Management System) algorithms by charging and discharging using REC (Renewable Energy Certificate) weights. The application made it possible to stabilize the distribution system.

As for small-scale renewable power sources of less than 1 MW, the policy of ensuring access to the power grid is in place, and the business and demand for connecting distributed power to the distribution system are increasing. As a result, research and related markets for system improvement such as active power control of general distribution lines are expected to be greatly expanded.

The present invention is a new technology proposal for resolving line congestion, by incorporating power quality stabilization, power grid analysis, monitoring, data acquisition technology, etc., and distributed power supply directly participates in the stabilization of system operation, thereby realizing distribution system management technology and future distribution. It provides the base technology for the construction of the system information and communication network, and induces cost reduction required for installation of other system compensation facilities due to participation in system stabilization

As described above, it will be understood that the present invention is implemented in a modified form without departing from the essential characteristics of the present invention.

Therefore, the specified embodiments should be considered from a descriptive point of view rather than a limiting point of view, and the scope of the present invention is shown in the claims rather than the above description, and all differences within the scope equivalent thereto are included in the present invention. It will have to be interpreted.

10. Power price information determination unit 11. System voltage maintenance determination unit
12. ESS buffering judgment unit 13. Power consumption unit based on congestion
14. Voltage stabilization unit 15. Reactive power output control unit
20. Power price information judgment unit 21. Distribution line congestion level judgment unit
22. Voltage stabilization execution unit 23. Power calculation unit
24. Voltage stability determination and discharge control

Claims (18)

In order to control charging in the active distribution EMS based on the smart inverter of the solar ESS integrated system,
A power price information determination unit for determining power price information by performing the INV5 function of the smart inverter;
A system voltage maintenance determination unit that measures the connection point voltage ( V ) of the solar ESS integrated system to determine whether the system voltage is maintained within a lower limit value ( V _min ) and an upper limit value ( V _{max );}
An ESS buffer determination unit that determines whether the ESS of the solar ESS integrated system is fully charged;
A power consumption unit based on congestion that reduces generation power by performing INV2 function based on line congestion when ESS is fully charged, or uses solar power generation for load consumption;
Voltage stabilization unit for performing voltage stabilization using a solar inverter when out of the grid voltage maintenance range;
A reactive power output control unit that calculates the maximum reactive power ( Q _avail ) that can be supplied and outputs reactive power according to the grid connection point voltage, a reactive power output control unit that performs a function of VV11; a smart inverter-based active type of a solar ESS integrated system, comprising: Distribution EMS. In order to control the discharge in the active distribution EMS based on the smart inverter of the solar ESS integrated system,
A power price information determination unit that determines power price information by performing the INV5 function of the smart inverter;
A distribution line congestion level determination unit for determining a congestion level of the distribution line before discharging the stored power of the ESS;
A voltage stabilization performing unit performing voltage stabilization by compensating for reactive power by performing a VV11 mode when the connection point voltage exceeds the limit value;
A power calculation unit that calculates electric power that can be discharged so as not to exceed 10MW, which is the capacity of a domestic distribution line by performing INV2 function;
A smart inverter-based active distribution EMS of a solar ESS integrated system, comprising: a voltage stability determination and a discharge control unit for controlling the discharge by determining the voltage stability of the connection point before discharging the electric power charged in the ESS. The method according to claim 1 or 2, wherein the INV5 function is to determine whether the distributed power supply with storage capacity is charged and discharged and the charge/discharge ratio of the ESS using a price determination signal,
The INV2 function limits the output of distributed power at the system connection point, and when the amount of distributed power generation exceeds the limit, it reduces the amount of output or saves the excess amount of generation in the energy storage device.
The VV11 function produces reactive power (VarAval) according to the connection point voltage (VRef) without fluctuations in the active power output, and presents the number of reactive power that can be supplied as a percentage by considering the capacity of the inverter. Smart inverter-based active distribution EMS of a solar ESS integrated system, characterized in that it outputs reactive power of and outputs positive reactive power as the connection point voltage decreases. In order to control charging in the active distribution EMS based on the smart inverter of the solar ESS integrated system,
Determining power price information by the power price information determination unit;
Determining whether the system voltage is maintained within a lower limit value ( V _min ) and an upper limit value ( V _max ) by measuring the connection point voltage (V ) of the solar ESS integrated system in the grid voltage maintenance determination unit;
Determining whether the ESS is fully charged by the ESS buffer determining unit;
Consumption of solar power generated by the power consumption unit based on congestion when ESS is fully charged;
A method of controlling a smart inverter-based active distribution EMS of a solar ESS integrated system comprising; performing voltage stabilization using a solar inverter when the voltage stabilizing unit exceeds the grid voltage maintenance range. The method of claim 4, wherein the step of determining the power price information,
Smart inverter-based active distribution of a solar ESS integrated system, characterized in that distributed power with storage capacity using a pricing signal is achieved through the INV5 function of a smart inverter that determines whether or not the ESS is charged, discharged, and the rate of charging and discharging. EMS control method. The method of claim 4, wherein when it is determined that the grid voltage maintenance determination unit satisfies the grid voltage maintenance range, the INV4 function is performed to charge the solar power generation into the ESS,
The INV4 function allows the distributed power supply with storage capacity to participate in the increase or decrease of energy production, and the request command is made in a percentage of the maximum output of the corresponding energy storage device. Control method. The method of claim 4, wherein the power consumption unit based on the congestion level reduces the generated power by performing the INV2 function when active power of 10MW or more, which is the general line capacity of domestic distribution based on the line congestion, flows. Smart inverter-based active distribution EMS control method of a solar ESS integrated system, characterized in that using for load consumption. 8. The solar system according to claim 7, wherein the INV2 function limits the output of distributed power at the system connection point, and when the amount of distributed power generation exceeds the limit, it reduces the output amount or stores the extra generation amount in the energy storage device. Smart inverter-based active distribution EMS control method of optical ESS integrated system. The method of claim 4, wherein in the step of performing voltage stabilization,
Voltage stabilization is performed by the reactive power output of the solar inverter, and is possible only when the solar active power output ( P _pv ) is smaller than the capacity (S _inv ) of the solar inverter, and P _pv When is not less than S _inv , the active power of the solar power is reduced by executing the INV2 function, and the smart inverter base of the solar ESS integrated system, characterized in that it makes a margin for outputting reactive power to the solar inverter. Control method of active distribution EMS. The method of claim 9, wherein P _pv Calculates the maximum reactive power (Q _avail ) that can be supplied by considering and S _inv , and performs the VV11 function to output reactive power according to the voltage of the grid connection point,
A smart inverter-based active distribution EMS control method of a solar ESS integrated system, characterized in that the maximum reactive power output that can be supplied when performing the VV11 function is limited through Q _{avail calculation.} The method of claim 10, wherein the VV11 function produces reactive power (VarAval) according to the connection point voltage (VRef) without fluctuation of the active power output, and presents the numerical value of the reactive power that can be supplied in percent based on the capacity of the inverter,
A smart inverter-based active distribution EMS control method of a solar ESS integrated system, characterized in that as the connection point voltage increases, the negative reactive power is output, and as the connection point voltage decreases, the positive reactive power is output. In order to control the discharge in the active distribution EMS based on the smart inverter of the solar ESS integrated system,
Determining power price information by the power price information determination unit;
Determining a congestion level of a distribution line before discharging the stored power of the ESS by the distribution line congestion level determination unit;
When the distribution line is congested, the voltage stabilization unit performs the voltage stabilization function of the connection point, and when the distribution line is not congested, the power calculation unit calculates the maximum amount of power that can be discharged based on the capacity of the distribution line. ;
Voltage stability determination and discharge control by determining the voltage stability of the connection point before discharging the electric power charged in the ESS by the discharge control unit; and a smart inverter-based active distribution EMS of the solar ESS integrated system, comprising: Control method. The method of claim 12, wherein the power price information determination unit sells the electric power charged in the ESS by performing INV5, which determines whether the ESS is charged or discharged and the charge/discharge ratio of the distributed power supply with the storage capacity using the price determination signal. A method of controlling an active distribution EMS based on a smart inverter of a solar ESS integrated system, characterized in that acquiring power price information in case of doing so. The method of claim 12, wherein when the distribution line is not congested, in the step of calculating the maximum amount of power that can be discharged based on the capacity of the distribution line in the power calculation unit,
The maximum amount of power that can be discharged is calculated using the INV2 function, and the INV2 function limits the output of distributed power at the system connection point.If the amount of distributed power generation exceeds the limit, the amount of output is reduced or the energy storage device is spared. A smart inverter-based active distribution EMS control method of a solar ESS integrated system, characterized in that it is a function to store power generation. The method of claim 12, wherein when the distribution line is congested, in the voltage stabilization performing unit performing a voltage stabilization function of the connection point,
A method of controlling an active distribution EMS based on a smart inverter of a solar ESS integrated system, characterized in that it contributes to voltage stabilization by compensating for reactive power by performing the VV11 mode when the connection point voltage exceeds the limit value. The method of claim 15, wherein the VV11 function produces reactive power (VarAval) according to the connection point voltage (VRef) without fluctuations in the active power output, and presents the number of reactive power that can be supplied as a percentage in consideration of the capacity of the inverter. A smart inverter-based active distribution EMS control method of a solar ESS integrated system, characterized in that it outputs negative reactive power as the point voltage increases and positive reactive power as the connection point voltage decreases. The method of claim 12, wherein in the voltage stability determination and discharge control unit,
When the voltage of the connection point is within the limit, the VW51 function is performed to discharge according to the voltage of the connection point. If the voltage of the connection point is out of the limit, the WP41 mode is executed to output active and reactive power at the same time to stabilize voltage and discharge ESS. A method of controlling an active distribution EMS based on a smart inverter of a solar ESS integrated system, characterized in that performing at the same time. The method of claim 17, wherein the VW51 function is a function to adjust the amount of active power output according to the state of the voltage at the grid connection point, and decreases the amount of active power in proportion as the voltage at the grid connection point increases,
WP41 is a function to stabilize the voltage by adjusting the power factor according to the active power output from the grid connection point. WP41 is a smart inverter-based active distribution EMS control of a solar ESS integrated system, characterized in that the operation is input in the form of a curve. Way.

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