KR20200056159A - Fr-ess droop control apparatus and method using the same - Google Patents

Abstract

The present invention relates to a frequency regulation energy storage system (FR-ESS) droop control method and a FR-ESS droop control device using the same. According to an embodiment of the present invention, the FR-ESS droop control method comprises the steps of: calculating a renewable power generation proportion index by using power generator output information; comparing a difference value of the renewable power generation proportion index with a preset threshold; calculating a droop value of a FR-ESS using the renewable power generation proportion index in accordance with a comparison result; and controlling droop by providing the calculated droop value to the FR-ESS.

Description

FR-ESS droop control method and FR-ESS DROOP CONTROL APPARATUS AND METHOD USING THE SAME using the same

The present invention relates to a FR-ESS droop control method and an FR-ESS droop control apparatus using the same, and more specifically, to calculate the droop values (K) of a plurality of FR-ESS respectively, and to calculate the corresponding droop values for the corresponding FR-ESS It relates to a FR-ESS droop control method and a FR-ESS droop control device using the same to improve frequency stability through control of a frequency fluctuation width and a change rate when a power system generator is eliminated by transmitting the frequency droop control to the system. .

The power system means a system that connects power plants, substations, and loads with transmission lines to generate power and consume power. The power system needs to be constantly monitored for power demand, since demand and supply must be balanced by synchronizing power generation and consumption.

Power demand monitoring was easy to monitor in small-scale systems, but power demand is rapidly increasing due to industrial advancement and informatization, so power facilities are also becoming large-scale and complex, so it is no longer possible to effectively operate power systems by artificial methods. Reached.

Accordingly, recently, by using new technology facilities such as Energy Storage System (ESS), Flexible AC Transmission System (FACTS), and High Voltage Direct Current Transmission System (HVDC), the operation of integrated power facilities for efficient performance of power system operation and Automation is moving rapidly.

In particular, ESS has been focused on the field of energy for transportation such as hybrid electric vehicles (HEV) or electric vehicles (EV), and research on the large-capacity and long-term life of lithium-ion batteries has been conducted, and commercialization of large-sized lithium-ion batteries has begun.

In the field of large power storage, large-size batteries such as NAS (NaS) batteries and redox flow batteries are in the early stages of commercialization, and a new market is expected as a system for competing with self-generating facilities and improving the quality of power. These batteries are inferior in performance to lithium-ion batteries, but are particularly excellent in price / capacity, and are in a stage of being used for large-capacity power storage.

In recent years, the commercialization of domestic power grid input has been actively conducted in ESS, and a system for revitalizing growth is being prepared.

Moreover, an application method for improving stability of ESS having a high-speed behavior is being considered. Currently, 376 MW ESS is used as a reserve power for frequency adjustment in Korea.

ESS will be expanded and supplied to the entire power system along with an increase in the power of new and renewable energy according to the global trend of smart grid. However, when the proportion of new and renewable energy generation increases, the inertia of the power system decreases, and when the generator is dropped, the frequency drop fluctuation increases. This increase in the frequency of fluctuations in the frequency drop leads to a decrease in frequency stability, and in severe cases, a low frequency relay (UFR) operates, and wide-area outages may occur due to large-scale load blocking.

As described above, when the proportion of new and renewable power generation is increased by highlighting the advantages of the high-speed response characteristics of the ESS, the droop control of the FR-ESS (Frequency Regulation ESS) that can solve the problem of low inertia of the power system is desperately needed. to be.

Accordingly, when the ESS is used as a large-capacity power storage system, it is necessary to provide a method for controlling the droop of the frequency-adjusting ESS to improve frequency stability by controlling the frequency fluctuation width and rate of change.

Korean Registered Patent Publication No. 10-1678926 (registered on November 17, 2016)

The object of the present invention is to calculate the droop value (K) of a plurality of FR-ESS, respectively, and transmit the corresponding droop value to the corresponding FR-ESS to perform frequency droop control, so that the frequency fluctuation range and rate of change when the power system generator is dropped In order to improve the frequency stability through the control of the FR-ESS droop control method and to provide a FR-ESS droop control device using the same.

The FR-ESS droop control method according to the first embodiment of the present invention comprises the steps of calculating a specific gravity index of renewable power generation using generator output information; Comparing the difference value of the renewable power specific gravity index with a preset threshold; Calculating a droop value of a FR-ESS (Frequency Regulation ESS) using the new and renewable power specific gravity index according to the comparison result; And providing the calculated droop value to the FR-ES to control the droop.

The renewable power specific gravity index may be an index indicating the ratio of the output of the new and renewable generator to the output of the total generator.

The difference value may mean a difference value between an n (n is a natural number) -th calculated index value and an n + 1-th calculated index value.

에 의해 계산되고, 여기서, K₀는 신재생발전비중을 고려하지 않은 FR-ESS(10)의 드룹 기본값이고, B는 신재생발전비중 지수(α)가 전력계통에 적정하게 반영되기 위해 적용된 비례상수값일 수 있다.In the calculating step, the droop value K is an equation

Calculated by, where K ₀ is the default droop of FR-ESS (10) that does not take into account the proportion of new and renewable power generation, and B is the proportionality applied to reflect the renewable power specific gravity index (α) properly in the power system. It can be a constant value.

In addition, the FR-ESS droop control method according to the second embodiment of the present invention includes: calculating a generator output amount (Net Gen) excluding new and renewable information using generator output information; Checking whether the output amount of the generator excluding the new renewal is outside a previously identified Net Gen section; Determining a droop value of a predetermined FR-ESS according to the Net Gen section using the output amount of the generator excluding new and renewable according to the confirmation result; And providing the determined droop value to the FR-ESS to control the droop.

The output amount of the generator other than the renewable energy may be a difference value between the total generated power of the power system and the total output of the new and renewable generator.

The Net Gen section indicates a numerical range for the generator output amount other than the new and renewable, and each of the Net Gen sections may be assigned a droop value applied to FR-ESS.

In addition, the FR-ESS droop control apparatus according to the first embodiment of the present invention, at least one processor; And a memory for storing computer readable instructions, wherein the instructions, when executed by the at least one processor, cause the FR-ESS droop control device to generate a new and renewable power specific gravity index using generator output information. To calculate, compare the difference value of the renewable power specific gravity index with a preset threshold, and according to the comparison result, the droop value of the FR-ESS (Frequency Regulation ESS) using the new renewable power specific gravity index. May be calculated, and the calculated droop value may be provided to the FR-ES to control the droop.

에 의해 계산되고, 여기서, K₀는 신재생발전비중을 고려하지 않은 FR-ESS(10)의 드룹 기본값이고, B는 신재생발전비중 지수(α)가 전력계통에 적정하게 반영되기 위해 적용된 비례상수값일 수 있다.When the instructions are executed by the at least one processor, when the FR-ESS droop control device calculates the droop value, the droop value K is an equation.

Calculated by, where K ₀ is the default droop of FR-ESS (10) that does not take into account the proportion of new and renewable power generation, and B is the proportionality applied to reflect the renewable power specific gravity index (α) properly in the power system. It can be a constant value.

In addition, the FR-ESS droop control apparatus according to the second embodiment of the present invention, at least one processor; And a memory for storing computer readable instructions, wherein the instructions, when executed by the at least one processor, cause the FR-ESS droop control device to generate generator output, excluding renewable information using generator output information. (Net Gen) is calculated, and it is checked whether or not the output amount of the generator other than the renewable is outside the previously identified Net Gen section, and according to the confirmation result, according to the Net Gen section using the output amount of the generator other than the new and renewable It is possible to determine the droop value of a predetermined FR-ESS, and to provide the determined droop value to the FR-ESS to control the droop.

The present invention calculates each droop value (K) of a plurality of FR-ESS, and transmits the corresponding droop value to the corresponding FR-ESS to perform frequency droop control, thereby controlling the frequency fluctuation width and rate of change when the power system generator is dropped. Through this, it is possible to improve the frequency stability.

In addition, the present invention can improve the reliability of the power system and prevent large-scale power outages such as large-scale generator chain failure and UFR load blocking prevention.

In addition, the present invention can optimally manage the frequency fluctuation range and rate of change by controlling the droop of FR-ESS according to the specific gravity of the renewable power source.

In addition, the present invention can be operated economically and stably by resolving measures such as load blocking to maintain frequency stability.

1 is a diagram for a FR-ESS droop control apparatus according to an embodiment of the present invention,
Figure 2 is a view showing a control block of the FR-ESS of Figure 1,
3 is a diagram for a FR-ESS droop control method according to a first embodiment of the present invention,
4 is a diagram for a FR-ESS droop control method according to a second embodiment of the present invention,
Figure 5a is a diagram showing the frequency fluctuation range and the rate of change according to the increase in the output portion of the renewable power generation,
5B is a diagram showing that the frequency fluctuation range and the rate of change are improved by the FR-ESS droop control device.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in the following description and accompanying drawings, detailed descriptions of well-known functions or configurations that may obscure the subject matter of the present invention are omitted. In addition, it should be noted that the same components throughout the drawings are denoted by the same reference numerals as much as possible.

The terms or words used in the present specification and claims described below should not be interpreted as being limited to ordinary or lexical meanings, and the inventor appropriately defines terms as terms for explaining his or her invention in the best way. Based on the principle that it can be done, it should be interpreted as a meaning and a concept consistent with the technical idea of the present invention.

Therefore, the configuration shown in the embodiments and drawings described in this specification is only one of the most preferred embodiments of the present invention, and does not represent all of the technical spirit of the present invention, and can replace them at the time of this application. It should be understood that there may be equivalents and variations.

In the accompanying drawings, some components are exaggerated, omitted, or schematically illustrated, and the size of each component does not entirely reflect the actual size. The present invention is not limited by the relative size or spacing drawn in the accompanying drawings.

When a part of the specification "includes" a certain component, this means that other components may be further included instead of excluding other components, unless specifically stated to the contrary. Also, when a part is said to be "connected" to another part, this includes not only "directly connected" but also "electrically connected" with other elements in between.

Singular expressions include plural expressions unless the context clearly indicates otherwise. The terms "include" or "have" are intended to indicate the presence of features, numbers, steps, actions, components, parts or combinations thereof described in the specification, one or more other features or numbers or steps. It should be understood that it does not preclude the existence or addition possibility of the operation, components, parts or combinations thereof.

Also, the term "part" as used in the specification means a hardware component such as software, FPGA, or ASIC, and "part" performs certain roles. However, "part" is not meant to be limited to software or hardware. The "unit" may be configured to be in an addressable storage medium or may be configured to reproduce one or more processors. Thus, as an example, "part" refers to components such as software components, object-oriented software components, class components and task components, processes, functions, attributes, procedures, Includes subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, database, data structures, tables, arrays and variables. The functionality provided within components and "parts" may be combined into a smaller number of components and "parts" or further separated into additional components and "parts".

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains may easily practice. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. In addition, in order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and like reference numerals are assigned to similar parts throughout the specification.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a diagram for a FR-ESS droop control apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing a control block of the FR-ESS of FIG. 1.

As illustrated in FIG. 1, the FR-ESS droop control apparatus 100 according to an embodiment of the present invention receives generator output information of a power system through an EMS (Energy Management System), etc., and stores multiple energy for frequency adjustment. Frequency droop control is performed by calculating the droop value (K) of the device (Frequency Regulation Energy Storage System) (hereinafter referred to as 'FR-ESS') 10 and transmitting the droop value to the corresponding FR-ESS 10 By performing it, it is possible to improve the frequency stability through control of the frequency fluctuation range and the rate of change when the power system generator is eliminated.

To this end, the FR-ESS droop control device 100 includes at least one processor and memory for storing computer readable instructions. That is, when the computer-readable instructions stored in the memory are executed by the at least one processor, the FR-ESS droop control apparatus 100 includes a FR-ESS droop control method (FIGS. 3 and 4 to be described later). See).

Referring to FIG. 2, the FR-ESS droop control apparatus 100 calculates the droop value K of the FR-ESS 10, respectively, and transfers the droop value K to the corresponding FR-ESS 10. Then, the FR-ESS 10 controls the output for frequency droop control of the power system by using the droop value K transmitted from the FR-ESS droop control device 100.

Specifically, the FR-ESS 10 first receives the frequency f _sys of the power system and compares it with a reference frequency f _ref to calculate a comparison value f _ref ―f _sys . Thereafter, the FR-ESS 10 calculates the output adjustment value ΔP proportional to the droop value K, where the comparison value f _ref ―f _sys is a gain value. Then, the FR-ESS 10 calculates the ESS output value P _{ESS_OUT} by reflecting the output adjustment value ΔP in the reference ESS input value P _{ESS_IN} . At this time, the FR-ESS 10 controls the output with the ESS output value (P _{ESS_OUT} ). Here, the ESS output value (P _{ESS_OUT} ) is limited from P _MAX to P _MIN by the ESS rated capacity.

On the other hand, the droop value K is related to the speed adjustment rate δ as shown in Equation 1 below.

Here, P _N is the rated capacity (㎿) of the ESS, f _N is the rated frequency (50 Hz or 60 Hz), and δ is the speed adjustment rate (%). As in Equation 1 above, the droop value K represents an inverse relationship between the speed adjustment ratio (δ).

As described above, the present invention may be implemented by applying a speed adjustment rate corresponding to it instead of the droop value K, but for convenience of description, only the droop value K will be described.

As described above, the FR-ESS droop control device 100 periodically calculates the droop value (K) or the speed adjustment rate (δ), which is the gain value of the FR-ESS 10, according to the proportion of new and renewable power generation. Provided, the frequency stability of the FR-ESS 10 is changed by changing the frequency of the power system, thereby improving the frequency stability.

3 is a diagram for a FR-ESS droop control method according to a first embodiment of the present invention. Here, a method of controlling the droop of the FR-ESS 10 based on the 'renewable power generation index (α)' by the FR-ESS droop control apparatus 100 will be described.

First, the FR-ESS droop control device 100 periodically receives generator output information of a power system through EMS or the like, and calculates a new renewable power specific gravity index α using the generator output information (S101).

Here, the new renewable power specific gravity index α is an index indicating the ratio of the output of the new and renewable generators to the total output of the generators, and is calculated as in Equation 2 below.

Subsequently, the FR-ESS droop control device 100 compares the difference value (Δα) of the renewable power specific gravity index (α) with a preset threshold (S102). Here, the difference value (Δα) of the new renewable power specific gravity index (α) is the difference between the n (n is a natural number) -th calculated index value (α _n ) and the n + 1-th calculated index value (α _{n + 1} ). Means That is, Δα = α _{n + 1} −α _n .

At this time, the FR-ESS droop control device 100 uses the new renewable power specific gravity index α when the difference value Δα of the new renewable power specific gravity index α exceeds a predetermined threshold (S102). -The droop value (K) of the ESS (10) is calculated (S103), and the droop value (K) is provided to each FR-ESS (10) to control the droop (S104).

Here, the droop value K of the FR-ESS 10 is calculated as in Equation 3 below. K ₀ is the droop default value of FR-ESS (10) that does not take into account the specific gravity of new and renewable power generation, and B is the proportionality constant value applied to properly reflect the renewable power specific gravity index (α) in the power system.

As described above, the FR-ESS droop control apparatus 100 controls the droop of the FR-ESS 10 to improve the frequency stability of the power system by repeatedly performing the method according to the first embodiment of the present invention.

4 is a diagram for a FR-ESS droop control method according to a second embodiment of the present invention. Here, a description will be given of a method for the FR-ESS droop control device 100 to control the droop of the FR-ESS 10 based on 'Generator output amount excluding new and renewable' (Net Gen).

First, the FR-ESS droop control device 100 periodically receives generator output information of a power system through EMS or the like, and uses the generator output information to calculate a generator output amount (Net Gen) excluding renewable energy (S201).

Here, the generator output amount (Net Gen) excluding the new and renewable energy is a difference between the total power generation (Gen) of the power system and the total power (new and renewable Gen) of the new and renewable generator, and is calculated as in Equation 4 below. The unit is ㎿.

Subsequently, the FR-ESS droop control device 100 checks whether the generator output amount (Net Gen) excluding new renewal is out of the previously identified Net Gen section (ie, the currently operating Net Gen section) (S202).

Here, the Net Gen section represents a numerical range for the generator output amount (Net Gen) excluding new and renewable, and each of the Net Gen sections is assigned a droop value (K) applied to FR-ESS as shown in Table 1 below.

Net Gen section Droop value (K) Section 1 (NG1 ~ NG2) K1 Section 2 (NG2 ~ NG3) K2 Section 3 (NG3 ~ NG4) K3 … … Section n (NGn ~ NG [n + 1]) Kn

In addition, the previously identified Net Gen section corresponds to a numerical range that is generated by the generator output amount (Net Gen) excluding the renewable energy calculated before step S201.

At this time, when the FR-ESS droop control device 100 is out of the Net Gen section where the generator output amount (Net Gen) excluding new regeneration is previously identified (S202), the Net Gen section is used using the generator output amount (Net Gen) excluding the new regeneration. The droop value (K) of the predetermined FR-ESS (10) is determined according to (S203), and the droop value (K) is provided to each FR-ESS (10) to control the droop (S204).

That is, the FR-ESS droop control device 100 searches for a table capable of confirming a predetermined droop value according to the Net Gen section of Table 1, and corresponds to the generator output amount (Net Gen) excluding the renewable energy calculated in step S201. The droop value to be determined can be easily determined.

For example, when the previously identified Net Gen section is the second section and the generator output amount (Net Gen) excluding the renewable energy calculated in step S201 is included in the third section, the FR-ESS droop control device 100 Since it is out of the previously identified Net Gen section, the droop value corresponding to the '3rd section' of the Net Gen section is determined as 'K3'.

As described above, the FR-ESS droop control apparatus 100 controls the droop of the FR-ESS 10 in order to improve the frequency stability of the power system by repeating the method according to the second embodiment of the present invention.

FIG. 5A is a diagram showing a change in frequency fluctuation range and a change rate according to an increase in output density of a new and renewable power source, and FIG. 5B is a view showing a change in frequency fluctuation range and change rate by the FR-ESS droop control device.

Referring to FIG. 5A, when a generator is dropped from a power system or a load rapidly increases, a frequency decreases due to supply and demand imbalance. However, in this case, as the output weight of the new and renewable power source increases, the frequency fluctuation range and rate of change change. In other words, when there is no specific gravity of the output of a new and renewable power source (A curve), when the specific gravity of a new and renewable power source is increased to 10% (B curve), when the specific gravity of a new and renewable power source is increased, the frequency drop fluctuation range and rate of change It can be seen that this is greatly increased.

Referring to FIG. 5B, it can be seen that when the droop value K is changed by applying the FR-ESS 10 (C1 curve and C2 curve), the frequency drop fluctuation range and rate of change are reduced. That is, the FR-ESS droop control apparatus 100 controls the droop value K of the FR-ESS 10 to improve frequency stability.

The method according to some embodiments may be implemented in the form of program instructions that can be executed through various computer means and may be recorded on a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, or the like alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the present invention, or may be known and available to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CDROMs, DVDs, and magneto-opticals such as floptical disks. And hardware devices specifically configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language codes that can be executed by a computer using an interpreter, etc., as well as machine language codes produced by a compiler.

Although the above description has been described with a focus on the novel features of the present invention applied to various embodiments, a person skilled in the art may have the apparatus and method described above without departing from the scope of the present invention. It will be understood that various deletions, substitutions, and modifications are possible in the form and details of the. Accordingly, the scope of the present invention is defined by the appended claims rather than in the above description. All modifications within the equivalent scope of the claims are covered by the scope of the present invention.

10; FR-ESS
100; FR-ESS droop control device

Claims (14)

Calculating a specific gravity index of new and renewable power generation using the generator output information;
Comparing the difference value of the renewable power specific gravity index with a preset threshold;
Calculating a droop value of a FR-ESS (Frequency Regulation ESS) using the new and renewable power specific gravity index according to the comparison result; And
Providing the calculated droop value to the FR-ES to control the droop;
FR-ESS droop control method comprising a.
According to claim 1,
The renewable power specific gravity index,
FR-ESS droop control method, which is an index indicating the ratio of the output of new and renewable generators to the total generator output.
According to claim 1,
The difference value is,
The FR-ESS droop control method means a difference between an n (n is a natural number) -th calculated exponent and an n + 1-th calculated exponent.
According to claim 1,
The calculation step,
The droop value (K) is an equation

Is calculated by,
Here, K ₀ is the default droop of FR-ESS (10) that does not take into account the proportion of new and renewable power generation, and B is the proportional constant value applied to reflect the renewable power specific gravity index (α) properly in the power system, FR-. ESS droop control method.
Calculating a generator output amount (Net Gen) excluding new and renewable information using the generator output information;
Checking whether the output amount of the generator excluding the new renewal is outside a previously identified Net Gen section;
Determining a droop value of a predetermined FR-ESS according to the Net Gen section using the output amount of the generator excluding new and renewable according to the confirmation result; And
Providing the determined droop value to the FR-ESS to control the droop;
FR-ESS droop control method comprising a.
The method of claim 5,
The output of the generator, excluding the new and renewable,
FR-ESS droop control method, which is the difference between the total generation output of the power system and the total output of the new and renewable generator.
The method of claim 5,
The Net Gen section,
It represents the numerical range for the output of the generator excluding the new and renewable,
In each of the Net Gen section,
FR-ESS droop control method in which the droop value applied to FR-ESS is allocated.
FR-ESS droop control device,
At least one processor; And
And a memory for storing computer readable instructions.
The instructions, when executed by the at least one processor, cause the FR-ESS droop control device to:
Use the generator output information to calculate the specific gravity index for new and renewable power generation,
To compare the difference value of the renewable power specific gravity index and a preset threshold,
According to the comparison result, the droop value of the FR-ESS (Frequency Regulation ESS) is calculated using the renewable power specific gravity index,
FR-ESS droop control device to control the droop by providing the calculated droop value to the FR-ES.
The method of claim 8,
The renewable power specific gravity index,
FR-ESS droop control device, which is an index indicating the ratio of the output of new and renewable generators to the total generator output.
The method of claim 8,
The difference value is,
FR-ESS droop control device which means the difference value between n (n is a natural number) th calculated index value and n + 1th calculated index value.
The method of claim 8,
The instructions, when executed by the at least one processor, cause the FR-ESS droop control device to:
When calculating the droop value, the droop value K is an equation

Calculated by, where K ₀ is the default droop of FR-ESS (10) that does not take into account the proportion of new and renewable power generation, and B is the proportionality applied to reflect the renewable power specific gravity index (α) properly in the power system. FR-ESS droop control device with constant value.
FR-ESS droop control device,
At least one processor; And
And a memory for storing computer readable instructions.
The instructions, when executed by the at least one processor, cause the FR-ESS droop control device to:
Using the generator output information, calculate the generator output amount (Net Gen) excluding new and renewable,
Make sure that the output of the generator, excluding the new and renewable, is outside the previously identified Net Gen section,
According to the result of the check, the droop value of a predetermined FR-ESS is determined according to the Net Gen section by using the output amount of the generator excluding the new regeneration,
FR-ESS droop control device to control the droop by providing the determined droop value to the FR-ESS.
The method of claim 12,
The output of the generator, excluding the new and renewable,
FR-ESS droop control device, which is the difference between the total generation output of the power system and the total output of the new and renewable generator.
The method of claim 12,
The Net Gen section,
It represents the numerical range for the output of the generator excluding the new and renewable,
In each of the Net Gen section,
FR-ESS droop control device in which the droop value applied to FR-ESS is assigned.

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