KR101704252B1 - Apparatus and method for operating stand-alone microgrid - Google Patents

Abstract

The present invention relates to an operation apparatus and an operation method for a small-sized independent-type microgrid system which is separated from a power system and is operated. The independent-type microgrid operation apparatus comprises: a data acquisition unit which collects measurement information and weather information with respect to power generators, an energy storage unit, and a load which are included in an independent-type microgrid system; a prediction unit which calculates a predicted power generation amount and a predicted load amount for a second period of renewable power generation facilities among the power generators for a next first period based on the measurement information and the weather information; a control amount calculation unit which outputs control parameters for the power generators, the energy storage unit, and the load for the second period based on the predicted power generation amount and the predicted load amount for the second period; and a control unit which controls the power generators, the energy storage unit, and the load based on the control parameters. An internal combustion power generator among the power generators, and the energy storage unit are connected in parallel to a distribution line connected to the load.

Description

[0001] APPARATUS AND METHOD FOR OPERATING STAND-ALONE MICROGRID [0002]

The present invention relates to an apparatus and method for operating a stand-alone microgrid, and more particularly to an apparatus and method for operating a small stand-alone microgrid system that operates separately from a power grid.

Most of the islands and isolated areas in the world, where the domestic power system is not linked, supply electricity using small scale internal combustion power generation. Most of these areas have high costs of transporting fuel, so they can not afford to pay for the same amount of electricity as the area where the power system is connected.

 Currently, there is no fuel transportation cost in these areas, and new and renewable energy, which is environment friendly energy that does not emit greenhouse gas, is spreading. However, in the case of new and renewable energy, since the power generation output is fluctuated due to the climate environment, the energy storage device such as a battery and the internal combustion electric power generator are necessarily required to satisfy the fluctuation of electricity consumption of the customer.

Such a small stand-alone micro grid system basically stores all the electricity generated by the renewable energy source into the battery, and the customer receives electricity from the battery. In addition, such a stand-alone micro grid system has a system of charging the battery by starting the internal combustion engine generator when both the power generation amount of the renewable energy source and the battery charging amount is insufficient.

The most problematic part of the system is that the life of the battery is shortened by frequent charging and discharging of the battery. Moreover, such a battery is formed at a relatively high price, and there is a problem of high replacement cost. However, the small stand-alone microgrid system described above is charged with the output of a new and renewable energy source and uses electricity whenever necessary. As a result, the battery life is rapidly reduced due to frequent charging and discharging of the battery.

Therefore, there is a need for an operating device that allows such a small microgrid system to automatically operate in consideration of battery life. However, in the present world, the operating system that is implemented through the technology of Smart Grid and Micro Grid in most countries is a technology for controlling resources to perform various control, and this is a large scale for applying to a book area or an isolated area There is a problem in that it can not be applied because of different operating methods.

Korean Patent Publication No. 2002-0080614 (Title: Apparatus and Method for Supplying Combined Generating Power Supply)

It is an object of the present invention to provide an apparatus and method for operating a small scale independent microgrid capable of performing an appropriate charging and discharging operation of an energy storage device, that is, an essential element of a stand-alone microgrid system.

In addition, the present invention minimizes the number of control points by controlling only the energy storage device and the emergency generator to optimize operation considering the capacity of the battery in consideration of the special situation of the independent microgrid system, And to provide a small stand-alone microgrid operating apparatus and method.

In order to solve the above problems, an operating apparatus for a stand-alone micro grid system operated separately from a power system of the present invention includes measurement information and weather information on generators, an energy storage unit, and a load included in a stand- A data acquisition unit for collecting data; A predictor for calculating a predicted generation amount and a predicted load of a new renewable generation facility among the generators for a first period based on the measurement information and the weather information; A control amount calculation unit for calculating control parameters for the generators, the energy storage unit, and the load for each second period based on the predicted generation amount and the predicted load amount for each second period; And a control unit for controlling the generators, the energy storage unit, and the load based on the control parameters, and the internal combustion generator and the energy storage unit of the generators are connected in parallel to the distribution line connected to the load.

In addition, the independent microgrid operating apparatus of the present invention may further include a storage state determiner for determining a state of the energy storage unit by comparing a remaining charge amount stored in the energy storage unit with a predetermined normal charge range .

In addition, when the charge remaining amount exceeds the normal charge range, the control unit stops operation of the internal combustion engine, drives a controllable load including a water supply pump and an unused dump load, It is possible to control the remaining charge amount to fall within the normal charge range.

Further, when the charge remaining amount is less than the normal charge range, the control unit activates at least one facility of the renewable power generation facilities, and stops the operation of the controllable load including the water supply pump and the unused dump load, It can be controlled so as to fall within the charging range.

The control amount calculating unit may calculate the control parameter such that the sum of the fuel cost and the starting cost of the internal combustion engine is minimized for each second period.

In addition, the fuel cost of the internal combustion engine can be calculated based on the power generation cost for the minimum load of the internal combustion engine, the operating state of the internal combustion engine generator, the marginal cost in each power generation section longer than the minimum load, and the output value.

The control amount calculating unit calculates a control amount of the internal combustion engine by subtracting the output value in the current cycle from the output value in the current cycle and equal to or less than the output evaporation rate of the internal combustion engine, The control parameter can be calculated so as to be equal to or less than the output deceleration rate.

In addition, the micro-grid operating apparatus of the present invention collects measurement information and meteorological information performed through the data acquisition unit, and calculates the predicted power generation amount and the predicted load amount for each second period, And a verifying unit for verifying the predicted power generation amount and the predicted load calculated in the previous period by comparing the predicted load with the measurement information collected in the current period.

Also, the control unit may control the generator, the energy storage unit, and the energy storage unit using the control parameter only when the difference between the predicted power generation amount and the predicted load amount calculated in the previous period and the measured power generation amount and the measured load included in the measurement information is within a predetermined threshold error range. And control of the load.

According to another aspect of the present invention, there is provided a method of operating a stand-alone micro grid system operating independently of a power grid of the present invention, Collecting measurement information and weather information; Calculating a predicted generation amount and a predicted load of the renewable generation facility among the generators for a second period based on the measurement information and the weather information by the prediction unit; Calculating a control parameter for the generators, the energy storage unit, and the load for the second period based on the predicted power generation amount and the predicted load amount for the second period by the control amount calculating unit; And performing control on the generators, the energy storage unit, and the load based on the control parameters by the control unit, and the internal combustion generator and the energy storage unit of the generators may be connected in parallel to the distribution line connected to the load.

In addition, the independent microgrid operating method of the present invention further includes a step of determining a state of the energy storing unit by comparing the remaining charged amount stored in the energy storing unit with a preset normal charging range by the storing unit state determining unit can do.

In addition, the independent microgrid operating method of the present invention is characterized in that when the remaining charge amount exceeds the normal charge range, the control unit stops the operation to the internal combustion electric generator, and the controllable unit including the water supply pump and the unused dump load And controlling the charge remaining amount to fall within the normal charge range by causing the load to be driven and stopping at least one of the renewable generation facilities.

In addition, the independent microgrid operating method of the present invention is characterized in that when the remaining charge amount is less than the normal charge range, the control unit activates at least one facility of the renewable power generation facilities, and performs control including a water supply pump and an unused dump load And stopping the operation of the possible load so that the remaining charged amount falls within the normal charging range.

In addition, the step of calculating the control parameter may be performed so that the sum of the fuel cost and the starting cost of the internal combustion engine becomes minimum for the second period.

Further, the fuel cost of the internal combustion engine may be calculated based on the power generation cost for the minimum load of the internal combustion engine, the operating state of the internal combustion engine, the marginal cost in each power generation section over the minimum load, and the output.

The step of calculating the control parameter may further include calculating a control parameter based on a value obtained by subtracting the output value in the previous cycle from the output value in the current cycle for the internal combustion engine and a value obtained by subtracting the output value in the current cycle from the output value in the previous cycle Is less than or equal to the output decay rate of the internal combustion engine generator.

In addition, the step of collecting the measurement information and the meteorological information, and the step of calculating the predicted generation amount and the predicted load amount for the second period are repeatedly performed every predetermined period, and the microgrid operating method of the present invention, And comparing the predicted power generation amount and the predicted load amount with the measured information collected in the current period to thereby perform verification of the predicted power generation amount and the predicted load calculated in the previous period.

The step of performing control on the generators, the energy storage unit, and the load based on the control parameters may include the steps of: calculating a difference between the predicted generation amount and the predicted load calculated in the previous cycle and the measured generation amount and the measured load included in the measurement information, It can only be done within the error range.

According to the independent microgrid operating apparatus and method of the present invention, the existing small-scale internal combustion power generation system is designed not to be the main energy system but to be suitable for a system in which a small-scale new-generation power generation source is dominant. (SOC) of the battery can be managed by predicting the amount of new and renewable energy generation and load, charging and discharging the battery, and setting the output of the internal combustion engine generator and the controllable load amount so as to perform load leveling and peak shift. As a result, it is possible to drastically reduce the replacement cost of the energy storage unit (battery), which is the most expensive equipment in the system configuration.

In addition, according to the independent micro grid operating apparatus and method of the present invention, only the essential operating modules suitable for a small scale are mounted without using the existing complex operating system (EMS), thereby dramatically reducing the size of the operating apparatus, Based energy system.

1 is a conceptual diagram of a stand-alone micro grid operating system according to an embodiment of the present invention.
2 is a block diagram of a standalone microgrid operating system in accordance with an embodiment of the present invention.
FIGS. 3A and 3B are graphs for explaining control results of the independent microgrid operating apparatus according to an embodiment of the present invention when the remaining charge amount stored in the energy storage unit exceeds a predetermined normal charging range.
FIGS. 4A and 4B are graphs for explaining control results of a stand-alone microgrid operating apparatus according to an embodiment of the present invention when the charge remaining amount stored in the energy storage unit is less than a predetermined normal charge range.
5 is a flowchart illustrating a method of operating a stand-alone micro grid according to an embodiment of the present invention.
6 is a flowchart illustrating a control method of increasing the charge remaining amount stored in the energy storage unit according to an embodiment of the present invention.
7 is a flowchart illustrating a control method of reducing the charge remaining amount stored in the energy storage unit according to an embodiment of the present invention.

The present invention will now be described in detail with reference to the accompanying drawings. Hereinafter, a repeated description, a known function that may obscure the gist of the present invention, and a detailed description of the configuration will be omitted. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. Accordingly, the shapes and sizes of the elements in the drawings and the like can be exaggerated for clarity.

Hereinafter, a standalone microgrid operating system 1000 according to an embodiment of the present invention will be described.

1 is a conceptual diagram of a standalone microgrid operating system 1000 according to an embodiment of the present invention. 1, a stand-alone micro-operating system 1000 according to an embodiment of the present invention includes a small-scale stand-alone micro-grid system and a stand-alone micro-grid operating apparatus 100 according to an embodiment of the present invention ). First, let's look at a small stand-alone microgrid system.

1, a small stand-alone microgrid system includes an internal combustion generator 10, an energy storage device 20, a power converter 30, a transformer 40, loads 51, 52 and 53, And may include facilities (61, 62). 1, a small scale independent micro grid system according to an embodiment of the present invention includes an internal combustion engine 10 and an energy storage device 20 in parallel for efficient power supply to a distribution line dl .

The internal combustion engine generator 10 functions to perform power generation using diesel as fuel. Thus, the power generated by the internal combustion engine generator 10 can be used for charging the energy storage device 20, or can be supplied to the load 51, 52, 53 via the distribution line dl.

The energy storage device 20 functions to store the electric power generated from the internal combustion engine generator 10 and supply electric power to the load 50 when necessary. Here, the energy storage device 20 may be constituted by a battery or the like. That is, the power supplied to the loads 51, 52, and 53 is supplied from the internal combustion engine 10 and the energy storage device 20 along the power distribution line dl via the transformer 40.

The renewable energy generation facilities 61 and 62 function to generate electricity using renewable energy, for example, wind power and solar energy. Here, in the case of renewable energy, it is important to consider such weather conditions for the operation of new and renewable energy because the variation in the amount of generated electricity depends on the weather conditions.

A description will now be given of a stand-alone microgrid operating apparatus 100 according to an embodiment of the present invention. As described above, the independent microgrid operating apparatus 100 according to an embodiment of the present invention is characterized in that the microgrid operating system 100 includes a function specific to the small-scale independent microgrid system. That is, in the case of the conventional micro grid operating system, various functions can be performed due to the hierarchical structure of various operation application-database-SCADA. For example, such a function may include a first function of maintaining the voltage and frequency of the system by controlling the active power and the reactive power of the internal combustion electric power generators, and the first function of maintaining the voltage and frequency of the system by considering the marginal cost, The second function to redistribute, the third function to display various status of the system, the fourth function to calculate the amount of algae in the system, and the failure of any component of the line, transformer, And a fifth function for analyzing what type of failure is occurring.

However, in the case of the first function and the second function, in the case of a small scale stand-alone micro grid system, it is not suitable because there are no various internal combustion generators. In the case of the third function, it is necessary to reduce it to a level showing only the necessary points. In the case of the fourth function, in the case of the small-scale power generation complex, there is an excessive function . Finally, the fifth function is also not a necessary function in a small microgrid system.

Accordingly, the independent microgrid operating apparatus 100 according to an embodiment of the present invention is intended to perform a small independent system operation with a simple control point and a light operation. In addition, the independent microgrid operating apparatus 100 according to an embodiment of the present invention is characterized in that the lifetime of the battery is prevented from being shortened by frequent charging or discharging of the battery. Hereinafter, with reference to FIG. 2, a description will be given of a standalone microgrid operating apparatus 100 according to an embodiment of the present invention.

2 is a block diagram of a stand alone microgrid operating system 100 in accordance with an embodiment of the present invention. As described above, in the case of the stand-alone micro grid system, the main power source is a renewable energy source such as solar power and wind power in which the output varies randomly according to climatic conditions. Accordingly, the role of the battery, that is, the energy storage unit 20, is very important. The battery is very expensive equipment, and it is greatly influenced by the service life such as the amount of charge and the amount of discharge in addition to the outside temperature and humidity. The ambient temperature and humidity can be kept constant through the constant temperature and humidity facility, but it is difficult to control the charge and discharge amount of the battery.

Accordingly, the stand-alone micro grid operating apparatus 100 according to an embodiment of the present invention can calculate the available energy capacity of the battery based on the load amount and the renewable energy generation amount prediction data in the micro grid system operating the battery as the main control power source And to optimally control the charging / discharging range of the battery by performing start-up periodical planning and economical power supply to the internal combustion engine 10 which can be controlled in consideration of load resources. 2, the independent microgrid operating apparatus 100 according to an embodiment of the present invention includes a communication unit 110, a data acquisition unit 120, a prediction unit 130, A control unit 140, a control amount calculating unit 150, a verifying unit 160, and a control unit 170. Herein, each of the configurations included in the independent microgrid operating apparatus 100 according to an embodiment of the present invention is divided for the description of the present invention, and each of the configurations, for example, a central processing unit (CPU) Each function can be performed through one processing unit.

Hereinafter, an independent microgrid operating apparatus 100 according to an embodiment of the present invention will be described with reference to FIG.

First, the communication unit 110 performs communication with the external server 70 and the independent micro-grid system. Here, the external server 70 may include, for example, a weather station server that provides weather information. As described above, in the case of renewable energy, meteorological information is important because of its characteristics. Therefore, the stand-alone micro grid operating apparatus 100 according to an embodiment of the present invention can be operated by an external server 70 such as a meteorological server An interlocking process can be performed.

The data acquisition unit 120 can collect information from the external servers 70 and the respective configurations included in the independent microgrid system through the communication unit. Specifically, the data acquisition unit 120 may collect information from the external server 70, the internal combustion engine 10, the energy storage unit 20, and the load 50. Here, the information includes measurement information on the internal combustion engine 10, the energy storage 20, and the load 50, and weather information collected from the external server 70. Here, the measurement information may include an actual generation amount measured for the renewable power generation facility 60, a controllable load amount measured for the load 60, and an uncontrollable load amount. For example, controllable loads may include automatic power control (ASC) schedulable pumps, air conditioning loads, and so on.

Based on the measurement information and the weather information acquired through the data acquiring unit 120, the predicting unit 130 predicts the second period-related estimated generation amount and the predicted load amount of the renewable generation facility 60 among the generators . The prediction unit 130 may include a power generation amount predicting module 131 for predicting a power generation amount of the new and renewable power generation facility 60 and a load amount prediction module 132 for predicting a load amount of the load 50. [

Wherein the first period is longer than the second period. For example, the first period may be a day unit such as one day or two days, and the second period may be a time unit such as one hour or two hours. In general, the load pattern is similarly repeated every day. Accordingly, in the case of the first period, it can be set as d * 24 hours, such as 24 hours and 48 hours as necessary.

Here, the generation amount estimation module 131 calculates the amount of wind power generation and the amount of solar radiation using the wind speed and radiation pattern generated in units of a predetermined period (for example, 15 minutes) based on the weather information collected by the external server 70 It functions to predict the amount of photovoltaic generation. However, since the weather forecast may not be utilized according to the conditions of the external server 70 described above, the weather forecast and the existing observation data are used so that the prediction method may be different depending on the value of the weather forecast utilization value is high or low. We adopt a method of estimating power generation amount by reflecting the weight on one pattern.

That is, the power generation estimation module 131 extracts the solar radiation amount for the second period on the basis of the weather information received from the external server 70, derives the latest solar radiation pattern based on the measured radiation amount information, Solar power generation can be derived based on the extracted solar radiation value based on the measured information and the solar radiation pattern derived from the measured information. Also, the power generation amount predicting module 131 extracts the wind speed for the second period on the basis of the weather information received from the external server 70, derives the recent wind speed pattern based on the measured irradiation amount information, Based on the extracted wind velocity and the wind speed pattern derived from the measured information, the wind speed generation amount can be derived.

The load prediction module 132 performs the load prediction only for the uncontrollable load, not the controllable load described above. Here, the predicted load value may mean a three-phase bulk active power and a reactive power load for a predetermined first period (for example, 24 hours or 48 hours).

In addition, the information acquisition through the data acquisition unit 120 and the prediction unit 130 and the prediction of the amount of power generation and the amount of load can be repeatedly performed at predetermined intervals. Here, it is preferable that the predetermined period is set to be shorter than the second period, for example, 15 minutes or 30 minutes.

The control amount calculating unit 150 has a function of calculating control parameters for the generators 10 and 60, the energy storage unit 20, and the load 50 for the second period based on the predicted generation amount and the predicted load amount for the second period do. Here, the control parameter for each configuration can be determined as the objective function condition that the sum of the fuel cost and the start-up cost of the internal combustion engine is minimized, which can be expressed by Equation 1 below.

In Equation (1), the variable k represents the fuel cost of the energy storage unit 20, that is, the battery, and the SOC represents the final stored power amount. The physical conditions and energy balance between the internal combustion engine 10 and the energy storage unit 20 are reflected as constraints. And FLC represents the fuel cost (yuan / h) of the internal combustion engine i at time t. Specifically, the FLC _{i , j} is calculated from the minimum load generation cost FLC ^m _{i , t} , the i generator on / off state (u _{i, t} ), the minimum load, Can be expressed as a marginal cost (MC _{i , b} ) and an output (g _{i, t, b} ).

Also, STC _{i , j} represents the start-up cost of the internal combustion engine i at time t, which is added as a cost only at startup. Next, the output evaporation rate and the deceleration rate of the emergency generator are considered in order to obtain the optimum solution of the objective function that minimizes the cost while maintaining the balance of energy supply and demand in the renewable energy generation complex for the load varying with time t. The physical output conditions for the time are as follows.

Here, RUR _i and RDR _i represent the output evaporation rate [kW / h] and the output decay rate [kW / h] of the emergency generator i, respectively.

And, g _{i, t} and g _{i, t- 1} represent the output [kW] of internal combustion generator i at time t and time t-1, respectively. The on / off state u _{i, j} (0 or 1) of the internal combustion generator i at time t is defined as the start state s _{i , t} (0 or 1) and d _{i , t} (0 or 1) of the emergency generator i . This can be expressed by the following equation (4).

The control unit 170 controls the generators, the energy storage unit, and the load based on the control parameters.

The storage state determination unit 150 determines the state of the energy storage unit 20 by comparing the charge remaining amount stored in the energy storage unit 20 with a predetermined normal charge range. In the case of the energy storage unit 20, that is, the storage unit, since there is no additional fuel cost, the charge remaining amount (SOC) of the energy storage unit 20 can be expressed with efficiency for charging and discharging. At this time, the amount of charge g ^x _{i , t} and the amount of discharge g ^y _{i , t} according to the state of charge x (0 or 1) and discharge state y (0 or 1) Can not exceed the maximum charge value (g ^X _{i, t} ) and the maximum discharge value (g ^Y _{i, t} ), respectively. This can be expressed by the following equations (5) to (7).

That is, the charge and discharge output of the energy storage unit 20 should be within the physical capacity of the energy storage unit 20, and the SOC may be expressed by the following formula (8) ^M _{i , t} ) and the lower bound constraint (SOC ^m _{i , t} ). Preferably, the upper limit can be set in the range of 70 to 90%, and the lower limit can be set in the range of 10 to 30%. Relationship between the SOC and the above-described upper limit constraints (SOC ^M _{i, t)} and the lower limit constraints (SOC ^m _{i, t)} can be summarized as shown in equation (8) below.

Accordingly, a process of comparing the normal charging range between the upper limit and the lower limit of the charge remaining amount of the energy storage unit 20 through the control unit 170 is required. That is, if it is determined through the controller 170 that the remaining charge amount exceeds the normal charge range, it is necessary to reduce the remaining charge amount of the energy storage unit 20 to within the normal charge range. That is, when the charge remaining amount exceeds the normal charge range, the control unit 170 stops operation of the internal combustion engine 10 and drives the controllable load including the water supply pump and the unused dump load, The operation of at least one of the renewable generation facilities is stopped so that the charge remaining amount can be controlled to fall within the normal charge range. 3A and 3B. In FIGS. 3A and 3B, the x-axis represents time and the y-axis represents charge remaining amount, that is, SOC. The y-axis for the bar graph represents the amount of power (kW) generated by the internal combustion engine generator and the amount of water (kW) consumed by the water pump, that is, the load.

In this example, assuming that the upper limit is 80% in the normal charge range, it can be seen that the charge remaining amount is out of the normal charge range in the period from 35 to 41 hours. However, according to the independent microgrid operating apparatus 100 according to the embodiment of the present invention, as shown in FIG. 3B, the operation of the internal combustion engine generator 10 through the control unit 170 is stopped, A controllable load including a non-use dump load is driven and a series of processes are performed to stop the operation of at least one of the renewable generation facilities. Thus, as shown in region 33 in FIG. 3B, the amount of power in the water pump increases and, as shown in region 32, the SOC does not exceed the upper limit.

Referring again to FIG. As a result of the determination through the control unit 170, there may be a normal charge range of the charge remaining amount. In this case, it is necessary to increase the remaining charge amount to within the set charge range. That is, when the charge remaining amount is less than the normal charge range, the control unit 170 activates at least one facility of the renewable power generation facilities, stops the operation of the controllable load including the water pump and the unused dump load, Can be controlled to fall within the normal charging range. 4A and 4B. Like FIG. 3, the x-axis represents time in FIGS. 4A and 4B, and the y-axis represents charge remaining amount, that is, SOC. The y-axis for the bar graph represents the amount of power (kW) generated by the internal combustion engine generator and the amount of water (kW) consumed by the water pump, that is, the load.

In this example, assuming that the lower limit is 20% in the normal charge range, it can be seen that the charge remaining amount is less than the normal charge range in the period from 10:00 to 11:00. However, according to the independent microgrid operating apparatus 100 according to an embodiment of the present invention, as shown in FIG. 4B, at least one facility of the renewable power generation facilities through the control unit 170 is operated, The controllable load including the pump and the unused dump load is stopped. Accordingly, as shown in the area 42 in FIG. 4B, the internal combustion power generation amount increases, and the SOC does not violate the lower limit. Referring again to FIG.

The verification unit 160 performs verification of the predicted power generation amount and the predicted load calculated in the previous period by comparing the predicted power generation amount and the predicted load amount calculated in the previous period with the measurement information collected in the current period. As described above, the acquisition of the measurement information and the weather information performed through the data acquisition unit 120 and the calculation of the predicted generation amount and the predicted load amount for the second period performed through the prediction unit 130 are repeated do. Here, the preset period is shorter than the second period. As described above, in the case of renewable energy, it is possible to change the amount of generated electricity according to the weather conditions. Therefore, it is judged whether the predicted quantity in the previous cycle is similar to the measured value in the previous cycle.

That is, the control process using the control parameters through the control unit 170 may be performed in the following manner. That is, the control unit 170 determines whether the difference between the predicted power generation amount and the predicted load amount calculated in the previous period determined by the verification unit 160, Only within the error range. If the difference between the predicted power generation amount and the predicted load amount calculated in the previous period and the measured power generation amount and the measured load included in the measurement information exceeds the predetermined threshold error range as a result of the verification, calculation and verification of the above- The prediction value can be corrected by performing the re-execution. Accordingly, the control unit 170 performs the control process only when the difference between the predicted value and the measured value does not deviate from the threshold error range.

5 is a flowchart illustrating a method of operating a stand-alone micro grid according to an embodiment of the present invention. As described above, the stand-alone microgrid operating system according to an embodiment of the present invention includes a small stand-alone microgrid system including generators, an energy storage unit and a load, and a standalone microgrid operating system according to one embodiment of the present invention. As shown in FIG. In the independent microgrid operating system according to an embodiment of the present invention, the internal combustion engine and the energy storage unit of the generators may be connected in parallel to the distribution line connected to the load.

Hereinafter, with reference to FIG. 5, a description will be given of a method of operating a stand-alone micro grid according to an embodiment of the present invention. In the following description, elements overlapping with those described above are omitted.

First, the data acquisition unit collects measurement information and weather information of the generators, the energy storage unit, and the load included in the independent microgrid system (S110). As described above, the measurement information includes power generation information for generators including an internal combustion engine and renewable energy generation facilities, and load information for loads. Here, the load information may include a controllable load indicating a load that can be controlled through the independent microgrid operating method according to an embodiment of the present invention, and an uncontrollable load amount that is not controllable.

Thereafter, the storage state determination unit compares the remaining charge amount stored in the energy storage unit with a predetermined normal charge range (S120). Specifically, step S120 is a step of determining whether the remaining charged amount falls within a preset normal charging range. As described above, in the case of an energy storage unit, such a battery, which can be constituted by a battery or the like, has a problem that its life is drastically reduced at frequent charging and discharging, excessive charging or discharging. Accordingly, according to the independent microgrid operating method of the embodiment of the present invention, the remaining charge amount of the energy storage unit can be checked, and the life of the energy storage unit can be further increased by making the remaining charge amount fall within the normal charge range. If it is determined in step S120 that the remaining charge amount falls within the normal charge range, control is passed to step S130. Otherwise, control is passed to step S170. First, let's look at a case where the charge remaining amount does not fall within the normal charge range.

In step S170, it is determined whether the remaining charge amount is less than the normal charge range. That is, when the remaining charge amount is less than the normal charge range, it can be seen that the present energy storage portion is in an excessive discharge state. Conversely, when the remaining charge amount exceeds the normal charge range, it is known that the energy storage unit is overcharged. As a result, if it is determined in step S170 that the remaining charge amount is less than the normal charge range, control is passed to step S180 to perform control to increase the charge remaining amount of the energy storage unit. Conversely, if it is determined in step S170 that the remaining charge amount exceeds the normal charge range, the control is transferred to step S190 to perform control to reduce the remaining charge amount of the energy storage unit.

Specifically, in step S180, when the charge remaining amount is less than the normal charge range, the control unit activates at least one facility of the renewable generation facilities and stops the operation of the controllable load including the water supply pump and the unused dump load So that the remaining charged amount falls within the normal charging range. Here, the process of operating at least one of the renewable power generation facilities may be performed according to a predetermined priority.

In step S190, when the charge remaining amount exceeds the normal charge range, the controller stops operation of the internal combustion generator among the generators and controls the controllable load including the water supply pump and the unused dump load And stopping the operation of at least one of the new and renewable power generation facilities so as to control the charge remaining amount to fall within the normal charge range. As with step S180, the process of stopping the facility of at least one of the controllable load and the renewable generation facilities can be performed according to a predetermined priority.

Now, when the charged amount is within the normal charging range, a description is made of the process to be performed. Step S130 is a step of calculating a predicted generation amount and a predicted load. Specifically, in step S130, the predicted power generation amount and the predicted load amount of the renewable generation facility of the generators for the first period are calculated based on the measurement information and the weather information collected in step S110 by the predictor . As described above, the predicted power generation amount mentioned in the step S130 represents a value for a renewable power generation facility, and the predicted load amount represents a predicted load amount of the load. Here, the predicted power generation amount, the predicted load amount, and the calculation method therefor have been described in detail with reference to FIG. 2, and further description thereof will be omitted.

Thereafter, the control amount calculating unit calculates a control parameter for the generators, the energy storage unit, and the load in the second period based on the second period-specific predicted power generation amount and the predicted load amount calculated in step S130 (step S140) . As described above, in step S140, the sum of the fuel cost and the startup cost of the internal combustion engine among the generators may be minimized for the second period. In addition, the fuel cost of the internal combustion engine can be calculated based on the power generation cost for the minimum load of the internal combustion engine, the operating state of the internal combustion engine generator, the marginal cost in each power generation section over the minimum load, and the output. In this control parameter, a value obtained by subtracting the output in the previous cycle from the output in the current cycle is equal to or lower than the output evaporation rate of the internal combustion engine, and a value obtained by subtracting the output in the current cycle from the output in the previous cycle is equal to or smaller than the output It can be calculated so as to be equal to or less than the decay rate. Since the method of calculating the control parameters has been described in detail with reference to FIG. 2, further description thereof will be omitted.

Thereafter, the verification unit compares the predicted generation amount and the predicted load amount calculated in the previous cycle with the measurement information collected in the current cycle to perform the verification of the predicted generation amount and the predicted load calculated in the previous cycle (S150) . As described above, the measurement information and the meteorological information collection performed in step S110, and the calculation of the predicted generation amount and the predicted load in the second period, which are performed through step S130, are repeatedly performed at predetermined intervals. Here, the preset period is shorter than the second period. As described above, in the case of renewable energy, it is possible to change the amount of generated electricity according to the weather conditions. Therefore, it is judged whether the predicted quantity in the previous cycle is similar to the measured value in the previous cycle. As a result of the determination in step S150, if it is determined that the difference between the predicted value and the measured value is within the predetermined threshold error range, control is passed to step S160. Otherwise, control passes to step S130 and the above-described prediction process is performed again to control the error of the predicted value to fall within the error range.

In operation S160, the control unit controls the generators, the energy storage unit, and the load based on the control parameters. Specifically, step S160 is performed only when the verification process determined in step S150 is passed. Otherwise, control is passed to step S110, and the above-described process is re-executed.

6 is a flowchart illustrating a control method of increasing the charge remaining amount stored in the energy storage unit according to an embodiment of the present invention. Hereinafter, with reference to FIG. 6, step S180 is further described. As described above with reference to FIG. 5, step S180 is a step performed through the control unit when the remaining charge amount of the energy storage unit is less than the normal charge range.

First, a step S181 for determining whether the renewable power generation facility is in operation is performed. As a result of the determination in step S181, if it is determined that the renewable power generation facility is in operation, the control is transferred to step S183. Otherwise, control passes to step S182.

Step S183 is a step for confirming whether or not an operable power generation facility exists. If it is determined in step S183 that there is an operable power generation facility, control is passed to step S184 to activate the power generation facility. Here, in step S184, the power generation facility may be operated according to a predetermined priority, instead of operating the power generation facility at random. If it is determined in step S183 that there is no operable power generation facility, the control is transferred to step S182.

Step S182 is a step of checking whether the controllable load is operating. As described above, the controllable load may be an automatic power control (ASC) schedulable pump, an air conditioner load, or the like. As a result of the determination in step S182, if it is determined that the controllable load is in operation, control is passed to step S185, and the step of disabling the load is performed. As with step S184, the suspension of the load can be made according to a predetermined priority, not randomly. As a result of the determination in step S182, if the controllable load is not in operation, that is, if there is no controllable load, the control is transferred to step S120 to re-execute the processes shown in FIG.

Also, in order to increase the charge remaining amount in the above explanation, it has been described as first checking whether the controllable load is operating after confirming the renewable power generation facility, but this is merely an example, It is also possible to perform the verification of the power generation facilities.

7 is a flowchart illustrating a control method of reducing the charge remaining amount stored in the energy storage unit according to an embodiment of the present invention. Hereinafter, with reference to FIG. 7, step S190 is further described. As described above with reference to FIG. 5, step S190 represents a step performed through the control unit when the remaining charge amount of the energy storage unit exceeds the normal charge range.

First, a step S191 for determining whether the internal combustion engine generator is operating is performed. As a result of the determination in step S191, if it is determined that the internal combustion engine is in operation, control is passed to step S192 to stop the operation of the internal combustion engine. As described above, the energy storage unit has a function of storing power generated from the internal combustion engine, but can shorten the life of the energy storage unit when the battery is overcharged. Accordingly, when the internal combustion engine generator is operated in an excessive charge state of the energy storage section, a process of stopping the internal combustion engine generator is required. As a result of the determination in step S191, if the internal combustion engine generator is not in operation, control is passed to step S193.

In step S193, it is determined whether the amount of power generated by the renewable power generation facility is greater than the load. As a result of the determination in step S193, if the power generation amount through the renewable power generation facility is equal to or greater than the load amount, control is passed to step S194. Otherwise, control passes to step S120, where the steps shown in FIG. 5 are performed again.

In step S194, it is determined whether or not there is a pump capable of operating among the controllable pumps. If it is determined in step S194 that there is a pump that can be operated among the controllable pumps, the control is transferred to step S195 so that the corresponding pump is operated. Thereafter, control is passed to step S193 to re-execute the above-described determination process. If it is determined in step S194 that there is no pump that can be operated further among the controllable pumps, control is passed to step S196.

Step S196 is a step of determining whether there is a dummy load that can be operated. As a result of the determination in step S196, if there is an operable dummy load, the control is transferred to step S197 and a process of operating the corresponding dummy load is performed. Thereafter, control is passed to step S193 to re-execute the above-described determination process. If it is determined in step S196 that there is no dummy load that can be further activated among controllable dummy loads, control is passed to step S198.

In step S198, it is determined whether there is a renewable generation facility that can be shut down. As a result of the determination in step S198, if there is a renewable power generation facility that can be shut down, the control is transferred to step S199 to stop the renewable power generation facility. Thereafter, control is passed to step S193 to re-execute the above-described determination process. As a result of the determination in step S196, if there is no facility that can suspend the renewable power generation facilities, control is passed to step S193.

In the description of step S190, the processes performed in steps S194, S196, and S198 are sequentially performed in the order of the steps described above. However, this is only an example, and the determination is performed in various orders, It is also possible. Also, it should be understood that the control performed in steps S195, S197, and S199 is performed according to predetermined priorities, not by randomly selecting and operating the equipment.

As described above, an optimal embodiment has been disclosed in the drawings and specification. Although specific terms have been employed herein, they are used for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

100: Standalone Micro Grid Operator
110: communication unit 120: data acquisition unit
130: Prediction unit 131: Power generation prediction module
132: load amount prediction module 140:
150: control amount calculating unit 160:
170:

Claims (18)

An operating device for a stand-alone microgrid system operating separately from a power system,
A data acquisition unit for collecting measurement information and weather information for the generators, the energy storage unit, and the load included in the independent microgrid system;
A predictor for calculating a predicted generation amount and a predicted load of the renewable generation facility among the generators for a second period based on the measurement information and the weather information for the first period;
A control amount calculating unit for calculating control parameters for the generators, the energy storage unit, and the load for each of the second periods based on the predicted generation amount and the predicted load amount for the second period; And
An energy storage unit and a load based on the control parameter, wherein the internal combustion generator and the energy storage unit of the generators are connected in parallel to a power distribution line connected to the load,
Wherein the control-
Calculating the control parameter such that the sum of the fuel cost and the starting cost of the internal combustion engine becomes minimum for the second period,
The fuel cost of the internal combustion engine is calculated on the basis of a power generation cost for the minimum load of the internal combustion engine generator, an operating state of the internal combustion engine generator, a marginal cost in each power generation section over a minimum load,
Wherein the first period is longer than the second period. The method according to claim 1,
Further comprising a storage unit status determination unit for determining a status of the energy storage unit by comparing a remaining charge amount stored in the energy storage unit with a predetermined normal charge range. 3. The method of claim 2,
Wherein,
Stopping operation of the internal combustion engine when the remaining charge amount exceeds the normal charge range, driving a controllable load including a water supply pump and an unused dump load, So that the remaining charge amount falls within the normal charge range by causing one operation to be stopped. 3. The method of claim 2,
Wherein,
When the charge remaining amount is less than the normal charge range, operating the at least one facility of the renewable generation facilities and stopping the operation of the controllable load including the water supply pump and the unused dump load, Of the microgrid system. ≪ Desc / Clms Page number 13 > delete delete The method according to claim 1,
Wherein the control-
Wherein a value obtained by subtracting an output value in a current period from an output value in a current cycle is equal to or lower than an output evaporation rate of the internal combustion engine with respect to the internal combustion engine, The control parameter is calculated so as to be equal to or less than a predetermined value. The method according to claim 1,
The method according to any one of claims 1 to 3, wherein the acquisition of the measurement information and the meteorological information performed by the data acquisition unit and the calculation of the predicted generation amount and the predicted load amount by the second period are repeated at predetermined intervals, Further comprising a verifying unit for verifying the predicted power generation amount and the predicted load calculated in the previous period by comparing the load with the measurement information collected in the current period. 9. The method of claim 8,
Wherein,
Only when the difference between the predicted power generation amount and the predicted load calculated in the previous period and the measured power generation amount included in the measurement information collected in the current period is within a predetermined threshold error range, Wherein the control unit performs control over the energy storage unit and the load. An operating method for a stand-alone microgrid system operating separately from a power grid,
Collecting measurement information and meteorological information on generators, an energy storage unit, and a load included in the independent microgrid system by a data acquisition unit;
Calculating a predicted generation amount and a predicted load amount of the renewable generation facility among the generators for a second period based on the measurement information and the weather information by the prediction unit;
Calculating a control parameter for the generators, the energy storage unit, and the load for each of the second periods based on the predicted power generation amount and the predicted load amount for the second period by the control amount calculating unit; And
And controlling the generator, the energy storage, and the load based on the control parameter by the control unit, wherein the internal combustion generator and the energy storage unit of the generators are connected in parallel to the distribution line connected to the load And,
The step of calculating the control parameter includes:
The sum of the fuel cost and the starting cost of the internal combustion engine is made minimum for the second period,
The fuel cost of the internal combustion engine is calculated on the basis of a power generation cost for the minimum load of the internal combustion engine, an operating state of the internal combustion engine generator, a marginal cost in each power generation section over a minimum load,
Wherein the first period is longer than the second period. 11. The method of claim 10,
Further comprising the step of determining the state of the energy storage unit by comparing the remaining charge amount stored in the energy storage unit with a preset normal charge range by the storage unit status determination unit, How to operate. 12. The method of claim 11,
When the remaining charge amount exceeds the normal charge range, the controller stops operation of the internal combustion engine, drives a controllable load including a water supply pump and an unused dump load, Further comprising controlling the charge remaining amount to fall within the normal charge range by causing the operation of at least one of the power generation facilities to be stopped. 12. The method of claim 11,
When the remaining charge amount is less than the normal charge range, at least one facility of the renewable generation facilities is operated by the control unit, and the operation of the controllable load including the water supply pump and the unused dump load is stopped, Further comprising controlling the remaining amount to fall within the normal charging range. delete delete 11. The method of claim 10,
The step of calculating the control parameter includes:
Wherein a value obtained by subtracting an output value in a current period from an output value in a current cycle is equal to or lower than an output evaporation rate of the internal combustion engine with respect to the internal combustion engine, Rate of the microgrid. ≪ / RTI > 11. The method of claim 10,
The step of collecting the measurement information and the weather information and the step of calculating the predicted generation amount and the predicted load amount for the second period are repeatedly performed every predetermined period,
The verification unit may further include a step of verifying the predicted generation amount and the predicted load amount calculated in the previous cycle by comparing the predicted generation amount and the predicted load amount calculated in the previous cycle with the measurement information collected in the current cycle Wherein the microgrid system is a stand-alone microgrid system. 18. The method of claim 17,
Wherein controlling the generators, the energy storage, and the load based on the control parameters comprises:
Characterized in that the determination is made only when the difference between the predicted power generation amount and the predicted load calculated in the previous period and the measured power generation amount and the measured load included in the measurement information collected in the current period is within a predetermined threshold error range. Way.

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