KR102234528B1 - SoC Management System and Method using Frequency Control and Offset at ESS Interfacing Generation Plant - Google Patents

Abstract

The present invention relates to an SoC management apparatus and method using frequency tracking control and offset addition of a power generation-linked ESS that gradually reduces the power value of the ESS while the ESS controls the frequency when the power system frequency fluctuates. A power generation control unit that senses that the frequency of the power system fluctuates according to a change in the output or load of the generator through (Electrical Network), and performs automatic power generation control and speed changer; The power system frequency is linked to the power generation control unit and the generator. If fluctuates, the ESS controls the frequency while setting the SOC offset to reduce the power value of the ESS, and at the same time, the ESS that manages the SoC by allowing the AGC operation of the generator to enter without impact; through valve control and turbine control. It includes; a power generation unit having a generator that generates power through auxiliary adjustment such as an increase or decrease in load or adjust the power generation so that the frequency of the power system maintains the rated frequency.

Description

SOC Management System and Method using Frequency Control and Offset at ESS Interfacing Generation Plant}

The present invention relates to power system control, and specifically, SoC management using frequency tracking control and offset addition of a power generation-linked ESS that gradually reduces the power value of the ESS by setting an SOC offset while the ESS controls the frequency when the power system frequency changes. It relates to an apparatus and a method.

The power system refers to a system in which a power plant, a substation, and a load are connected by a transmission line in response to electricity demand, from generation to consumption of electricity.

In such a power system, since power generation and consumption occur at the same time, demand and supply must be balanced. Accordingly, the power system requires continuous monitoring of the balance between supply and demand.

As the problem of unbalanced electricity supply and demand intensifies every year, ESS has recently been in the spotlight as a way to solve this problem.

ESS (Energy Storage System) is an energy storage system that controls various voltages/currents generated from distributed power or renewable energy, and connects to the power system or stores and uses idle energy as needed. Considering the enormous cost and construction time required for power plant investment against the increasing power demand, ESS has the advantages of equalizing power demand, stable operation of the power system, and active management.

In addition, ESS is essential for an efficient plan to increase the efficiency of use of smart grids and new and renewable energy, as new and renewable energies such as smart grids and solar or wind power generation are in the spotlight.

ESS has advantages such as power quality, maintenance, time shift, and energy conservation, thereby reducing investment in power plant facilities, improving power quality of new and renewable energy, and minimizing damage during power outages.

A typical energy storage system (ESS) includes a storage device (Battery), a Power Conditioning Syaetm (PCS), an Energt Management System (EMS), and a Battery Management System (BMS).

In power generation areas such as power generation sources, the emergence of new and renewable energy and small-scale distributed power generation has led to the emergence of large-scale and subdivided areas. In the transmission/distribution area, reserve capacity, The areas of power grid load distribution and frequency adjustment are emerging.

At the end user level, there is a need in the market that is divided into a variety of uses, such as energy storage to respond to peak demand, storage of renewable energy generation, and output response in case of power outages, and related ESS projects are rapidly increasing.

In ESS, the frequency regulation is to improve the supply capacity by adjusting the output frequency of the generator in operation to prevent power frequency fluctuations due to instantaneous demand fluctuations.

ESS in connection with such renewable energy needs to be accompanied by research on the problem of frequency adjustment and power peak adjustment.

In the prior art, each operated like a single ESS and a single power plant, and in the case of an ESS, the ESS was connected to a transmission network or a distribution network without a power plant connection.

As described above, in the prior art, when it detects that the frequency of the power system fluctuates due to fluctuations in the output or load of the generator, the frequency of the power system is adjusted to maintain the rated frequency, or the frequency mainsboat function is performed. In conjunction with the function, it performs auxiliary adjustment functions such as adjusting the power generation power of the linked power plant or increasing or decreasing the load.

Accordingly, a delay time occurs from the time when the output fluctuation or the load fluctuation of the power plant is found to the time when the frequency of the power system is fluctuated to perform frequency adjustment, and the power system frequency may decrease or increase during the delay time.

On the supplier side, if the frequency of the power system decreases during the delay time, there is a problem that the output of power plant auxiliary equipment and the control system may become unstable. If the frequency of the power system increases during the delay time, the frequency decreases. There is a problem that the limit width for continuous operation is less than that of the case.

In order to solve such a problem, a technology has been proposed in which an ESS (Energy Storage System) is connected to a generator and the ESS performs frequency correction in consideration of the operating conditions of the generator.

1 is a state diagram of SoC management and control of a conventional power generation-linked ESS.

SoC management control of power generation-linked ESS is to use ESS to maintain frequency regulation (frequency regulation) in order to maintain the reference frequency of 60Hz.

That is, the frequency of the system changes according to the load of the system, and when the system frequency decreases to 59.97Hz or less due to an increase in the load, the ESS is discharged to supply power to the system, and the frequency is 60.03Hz or more due to a decrease in the load. When rising to, the ESS is charged with electric power to maintain the frequency.

If the frequency is within the operating range and the SoC of the ESS is out of a certain range, it operates to keep the SoC within the operating range. The ESS output for SoC recovery operation discharges 10% or 15% of the rated output according to the SoC status.

By using the droop coefficient that determines the output of the ESS for the amount of frequency change, the ESS performs droop control for power system frequency correction, and changes the charge/discharge value to 0 when reducing the power value of the ESS after charging or discharging.

When the SoC is 80% or more, the energy storage device controls discharge, and when the SoC is less than 50%, it is controlled so that only charging according to the remaining SoC is possible.

However, the power system control technology using such a power generation-linked ESS has a limitation in stabilizing the frequency of the power system due to a large impact on the power grid when the power value changes abruptly.

Therefore, there is a need to develop a new control technology for stabilizing the frequency of the power system.

Republic of Korea Patent Publication No. 10-2019-0004587 Republic of Korea Patent Publication No. 10-2016-0028885 Republic of Korea Patent Publication No. 10-2016-0082271

The present invention is to solve the problem of the power system control technology of the prior art, when the power system frequency fluctuates, the ESS controls the frequency, and then gradually reduces the power value of the ESS with an SOC offset to increase the SOC management efficiency. An object of the present invention is to provide an SoC management apparatus and method using frequency tracking control and offset addition.

The present invention increases the SOC management efficiency of the ESS by gradually reducing the power value of the ESS by setting the SOC offset while the ESS controls the frequency when the power system frequency fluctuates in the combination of the generator and the ESS, and at the same time allowing the AGC operation of the generator to enter naturally. The purpose of this is to provide an SoC management apparatus and method using frequency tracking control and offset addition of power generation-linked ESS.

In the present invention, the power of the ESS should be reduced after charging or discharging (the set point of the generator is changed at this time) while the ESS performs droop control for power system frequency correction. Its purpose is to provide an SoC management apparatus and method using frequency tracking control and offset addition of a power generation-linked ESS so that power can be effectively reduced.

The present invention is helpful in recovering SOC by effectively reducing power by adding an offset rather than changing the charge/discharge value to 0 when reducing the power value of the ESS after charging or discharging with droop control. The purpose of this is to provide an SoC management apparatus and method using frequency tracking control and offset addition of a power generation-linked ESS that can be used.

The present invention is a SoC management device using frequency tracking control and offset addition of a power generation-linked ESS in which the change in the power value of the ESS does not change significantly during SOC management by controlling the frequency and SOC together in an SOC offset method, and Its purpose is to provide a method.

In the present invention, since the change in the power value of the ESS does not change rapidly, the power supply of the ESS decreases in the generator + ESS combination, and the generator can naturally enter when the power supply of the generator increases, thereby reducing the impact on the power grid. The purpose of this is to provide an SoC management apparatus and method using frequency tracking control and offset addition of a linked ESS.

The present invention effectively reduces the power by adding an offset when reducing the power value of the ESS, so that the combination of the generator and the ESS can operate more naturally, and reduces unnecessary power consumption by reducing the throttling loss of the generator. The purpose of this is to provide an SoC management apparatus and method using frequency tracking control and offset addition of a power generation-linked ESS.

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

The SoC management device using the frequency tracking control and offset addition of the power generation-linked ESS according to the present invention to achieve the above object is the frequency of the power system according to the output fluctuation or load fluctuation of the generator through an electrical network. A power generation control unit that senses a fluctuation in power generation and performs automatic power generation control and speed control (Speed Changer); When the power system frequency fluctuates in connection with the power generation control unit and the generator, the ESS controls the frequency and reduces the power value of the ESS by setting the SOC offset. At the same time, ESS that manages the SoC by allowing the AGC operation of the generator to enter without impact; adjusting the power generation power so that the frequency of the power system maintains the rated frequency through valve control and turbine control, or assisting with load increase or decrease. It characterized in that it comprises a; power generation unit having a generator that generates power through adjustment.

Here, the ESS and the power generation unit communicate with each other in the process of frequency tracking control and SOC offset addition control to perform cooperative control, so that the generator and the ESS share the role of frequency control.

In addition, the ESS controls droop and gradually reduces the power by adding an offset instead of changing the charge/discharge value to 0 when reducing the power value of the ESS after charging or discharging. It is characterized.

In addition, the ESS is a system frequency comparison unit that measures the power system frequency and SOC level and compares the power system frequency (f) with the upper limit of the frequency control deadband region (f _H ) and the lower limit of the frequency control deadband region (f _{L ).} ,The SOC level measured according to the comparison result of the system frequency comparison unit, the SOC overcharge prevention mode divider (SOC _H ), the SOC overdischarge prevention mode divider (SOC _L ), the SOC control deadband area upper limit (SOC _MH ) and the SOC control deadband It characterized in that it comprises a SoC comparison unit for comparing the lower region (SOC _ML).

으로 ESS 충방전 제어를 하는 ESS 충방전 제어부를 더 포함하는 것을 특징으로 한다.And the ESS is, when the SOC level measured by the comparison result of the SoC comparison unit does _{not exceed the SOC overcharge prevention mode division line (SOC H} ) or exceeds the SOC overdischarge prevention mode division line (SOC _L ).

It characterized in that it further comprises an ESS charging and discharging control unit for controlling the ESS charging and discharging.

)으로 변경하는 전력값 변경부를 더 포함하는 것을 특징으로 한다.And the ESS, if the SOC level measured by the comparison result of the SoC comparison unit _{is located between the lower limit of the SOC control deadband area (SOC ML} ) and the upper limit of the SOC control deadband area (SOC _MH ), the power value is 0 (

It characterized in that it further comprises a power value changing unit to change to ).

And the ESS, the SOC level measured by the comparison result of the SoC comparison unit exceeds the SOC overcharge prevention mode division line (SOC _H ), exceeds the upper limit of the SOC control deadband area (SOC _MH ), or the lower limit of the SOC control deadband area ( It characterized in that it further comprises a frequency offset control unit for additional SOC offset control when the _{SOC ML} ) does not exceed or does not exceed the SOC overdischarge prevention mode division line SOC _L.

And the system frequency comparison unit, a first system frequency comparison unit that determines whether the power system frequency (f) exceeds the frequency control deadband region upper limit (f _H ), and the power system frequency (f) is the frequency control deadband region lower limit A second system frequency comparison unit that determines whether it is located between (f _L ) and the upper limit of the frequency control deadband area (f _H ), and whether the power system frequency (f) does not exceed the _{lower limit of the frequency control deadband area (f L ).} It characterized in that it comprises a third system frequency comparison unit to determine.

In addition, the SOC comparison unit determines whether the measured SOC level exceeds the SOC overcharge prevention mode division line (SOC _H ) when the power system frequency (f) in the system frequency comparison unit _{exceeds the upper limit line (f H) of the frequency control deadband area.} SOC measured when the power system frequency (f) is located between the _{lower limit of the frequency control deadband region (f L} ) and the upper limit of the frequency control deadband region (f _H ) in the first SoC comparison unit and the system frequency comparison unit. A second SoC comparison unit that determines whether the level exceeds the SOC control deadband upper limit (SOC _MH ), the measured SOC level is the lower limit of the SOC control deadband area (SOC _ML ) and the upper limit of the SOC control deadband area (SOC _MH ) A third SoC comparison unit that determines whether it is located between, a fourth SoC comparison unit that determines whether the measured SOC level does _{not exceed the SOC control deadband region lower limit (SOC ML} ), and the power system frequency ( and a fifth SoC comparator for determining whether the measured SOC level exceeds the SOC overdischarge prevention mode division line SOC _L when f) exceeds the frequency control deadband lower limit line f _L.

_{In addition, the ESS} includes an SOC change unit that outputs the SoC change value (△SoC) according to the relationship between the ESS output (△P ESS) and the SoC for SoC management using the frequency tracking control and offset addition of the power generation-linked ESS, The SOC value conversion unit converts the SoC fluctuation value into the SoC frequency command value (K _f ) and outputs the converted value (f _ofs ) for frequency feedback, and the [measurement frequency-conversion value] (Δf-f _ofs ). It characterized in that it comprises a droop (Droop) control unit for controlling the ESS output (ΔP _{ESS) as an input.}

In addition, the ESS includes a SOC reference value change unit that changes the _{measurement frequency (Δf) to the SOC reference value (△SoC ref} ) and an ESS output (ΔP ESS) for SoC management using frequency tracking control and offset addition of the power generation-linked _ESS. ) And the SOC change unit that outputs the SoC fluctuation value (△SoC) according to the relationship between the SoC and the frequency error that changes the SOC error into a frequency error by inputting the _{SOC reference value (△SoC ref) and the SoC fluctuation value (△SoC).} It characterized in that it comprises a droop (droop) controller for controlling the output ESS _(ESS △ P) to enter the - (f _ofs Δf) output unit, and a frequency error output frequency error portion.

The SoC management method using the frequency tracking control and offset addition of the power generation-linked ESS according to the present invention to achieve other purposes, the SoC management method using the frequency tracking control and offset addition of the power generation-linked ESS is largely the power system frequency and SOC. A system frequency comparison step of measuring the level and comparing the power system frequency (f) with the upper limit of the frequency control deadband region (f _H ) and the lower limit of the frequency control deadband region (f _L ); according to the comparison result of the system frequency comparison step The measured SOC level is compared with the SOC overcharge prevention mode divider (SOC _H ) and the SOC overdischarge prevention mode divider (SOC _L ), and the SOC control deadband upper limit (SOC _MH ) and the SOC control deadband lower limit (SOC _{ML ).} SoC comparison step; The measured SOC level does not exceed the _{SOC overcharge prevention mode division line (SOC H} ), exceeds the SOC control deadband area upper limit (SOC _MH ), or does not exceed the SOC control deadband area lower limit (SOC _{ML ),} And a frequency offset control step of performing SOC offset additional control when the SOC overdischarge prevention mode division line SOC _{L is not exceeded.}

으로 ESS 충방전 제어를 하는 ESS 충방전 제어 단계를 더 포함하는 것을 특징으로 한다.Here, when the measured SOC level does _{not exceed the SOC overcharge prevention mode division line (SOC H} ) or the SOC overdischarge prevention mode division line (SOC _L ),

It characterized in that it further comprises an ESS charging and discharging control step of controlling the ESS charging and discharging.

)으로 변경하는 전력값 변경 단계를 더 포함하는 것을 특징으로 한다.And if the measured SOC level is between the lower limit of the SOC control deadband area (SOC _ML ) and the upper limit of the SOC control deadband area (SOC _MH ), the power value is set to 0 (

It characterized in that it further comprises a step of changing the power value to change to ).

And the system frequency comparison step, a first system frequency comparison step of determining whether the power system frequency (f) exceeds the frequency control deadband region upper limit (f _H ), and the power system frequency (f) is the frequency control deadband region The second system frequency comparison step to determine whether it is located between the lower limit line (f _{L ) and the upper limit line (f H} ) of the frequency control deadband area, and whether the power system frequency (f) does not exceed the _{lower limit line (f L) of the frequency control deadband area} It characterized in that it comprises a third system frequency comparison step of determining.

And the SoC comparison step, when the power system frequency (f) exceeds the upper limit of the frequency control deadband area (f _H ) in the grid frequency comparison step, whether the measured SOC level exceeds the SOC overcharge prevention mode division line (SOC _H ). In the first SoC comparison step to determine and the system frequency comparison step, measured when the power system frequency (f) is located between the _{lower limit of the frequency control deadband area (f L} ) and the upper limit of the frequency control deadband area (f _{H ).} The second SoC comparison step to determine whether the SOC level exceeds the SOC control deadband upper limit (SOC _MH ), and the measured SOC level is the SOC control deadband lower limit (SOC _ML ) and the SOC control deadband upper limit (SOC _MH). ), the third SoC comparison step to determine whether the measured SOC level does _{not exceed the SOC control deadband lower limit (SOC ML} ), and the power system frequency in the system frequency comparison step and a fifth SoC comparison step of determining whether the measured SOC level exceeds the SOC overdischarge prevention mode division line SOC _L when (f) exceeds the frequency control deadband region lower limit line f _L.

The SoC management apparatus and method using the frequency tracking control and offset addition of the power generation-linked ESS according to the present invention as described above has the following effects.

First, when the power system frequency fluctuates, the ESS controls the frequency and gradually decreases the power value of the ESS by setting the SOC offset to increase the SOC management efficiency.

Second, when the power system frequency fluctuates in the combination of the generator and ESS, the ESS controls the frequency and gradually decreases the power value of the ESS by setting the SOC offset, and at the same time, it increases the SOC management efficiency of the ESS by allowing the AGC operation of the generator to enter naturally.

Third, ESS performs droop control for power system frequency correction, and after charging or discharging, the power of the ESS must be reduced, but the power can be effectively reduced by adding an offset rather than changing the power to zero.

Fourth, when reducing the power value of the ESS after charging or discharging with droop control, it is a method of adding an offset rather than changing the charging/discharging value to 0, which will help effectively reduce power and recover SOC. To be able to.

Fifth, the SOC offset method is used to control the frequency and SOC together so that the change in the power value of the ESS does not change significantly during SOC management.

Sixth, since the change in the power value of the ESS does not change rapidly, the power supply of the ESS decreases in the generator + ESS combination, and when the power supply of the generator increases, the generator can naturally enter, thereby reducing the impact on the power grid.

Seventh, when reducing the power value of the ESS, the power is effectively reduced by adding an offset, so that the combination of the generator and ESS can operate more naturally, and the power consumed unnecessarily due to the reduction of throttle loss of the generator can be reduced. do.

1 is a state diagram of SoC management and control of a conventional power generation-linked ESS
2 is an overall configuration diagram of an SoC management apparatus using frequency tracking control and offset addition of a power generation-linked ESS according to the present invention
3 is a detailed configuration diagram of an SoC management apparatus using frequency tracking control and offset addition of a power generation-linked ESS according to the present invention
4 is a detailed configuration diagram of a system frequency comparison unit according to the present invention
5 is a detailed configuration diagram of an SOC comparison unit according to the present invention
6 is a state diagram of SoC management and control of the power generation-linked ESS according to the present invention
7A and 7B are detailed configuration diagrams of the SoC management control unit of the power generation-linked ESS according to the present invention
8 is a flow chart showing a SoC management method using frequency tracking control and offset addition of a power generation-linked ESS according to the present invention

Hereinafter, a preferred embodiment of an SoC management apparatus and method using frequency tracking control and offset addition of a power generation-linked ESS according to the present invention will be described in detail as follows.

Features and advantages of the SoC management apparatus and method using the frequency tracking control and offset addition of the power generation-linked ESS according to the present invention will be apparent through detailed description of each embodiment below.

2 is an overall configuration diagram of an SoC management apparatus using frequency tracking control and offset addition of a power generation-linked ESS according to the present invention.

The SoC management apparatus and method using the frequency tracking control and offset addition of the power generation-linked ESS according to the present invention is that when the power system frequency fluctuates in the combination of the generator and the ESS, the ESS controls the frequency and then gradually sets the SOC offset to the power value of the ESS. This is to increase the SOC management efficiency of ESS by reducing the voltage and allowing the AGC operation of the generator to enter naturally.

The SoC management apparatus using the frequency tracking control and offset addition of the power generation-linked ESS according to the present invention is the power system according to the output fluctuation or load fluctuation of the generator through the electrical network 100, as shown in FIG. A power generation control unit 200 that senses a change in frequency and performs automatic power generation control and speed control (Speed Changer), and when the power system frequency fluctuates in connection with the power generation control unit 200 and the generator, the ESS controls the frequency and offsets the SOC. The frequency of the power system is rated through ESS (300), which manages the SoC by gradually reducing the power value of the ESS and allowing the AGC operation of the generator to enter without impact, and the valve control and turbine control. A power system that has a generator that generates power through auxiliary adjustments such as adjustment of power generation or load increase or decrease to maintain the frequency, and power system stabilization through PSS (Power System Stabilization), Exciter, and Voltage Sensing. It includes a stabilization unit 500.

Here, the ESS 300 and the power generation unit 400 communicate with each other in the process of frequency tracking control and SOC offset addition control to perform cooperative control, so that the generator and the ESS share the frequency control role, taking into account the operating conditions of the generator. The ESS corrects the frequency and adjusts the SoC after frequency fluctuations occur to quickly control the frequency using the fast response characteristics of the ESS.

In addition, when the ESS power value is reduced after charging or discharging by controlling the droop, the ESS 300 effectively reduces the power by adding an offset rather than changing the charging/discharging value to 0 to recover the SOC. Try to be helpful at times.

The power generation-linked ESS according to the present invention includes the following configuration for SoC management using frequency tracking control and offset addition.

3 is a detailed configuration diagram of an SoC management apparatus using frequency tracking control and offset addition of a power generation-linked ESS according to the present invention.

으로 ESS 충방전 제어를 하는 ESS 충방전 제어부(33)와, 측정된 SOC 레벨이 SOC 제어 불감대 영역 하한선(SOC_ML)과 SOC 제어 불감대 영역 상한선(SOC_MH) 사이에 위치하면 전력값을 0(

)으로 변경하는 전력값 변경부(34)와, 측정된 SOC 레벨이 SOC 과충전 방지 모드 구분선(SOC_H)을 넘거나, SOC 제어 불감대 영역 상한선(SOC_MH)을 넘거나, SOC 제어 불감대 영역 하한선(SOC_ML)을 넘지 않거나, SOC 과방전 방지 모드 구분선(SOC_L)을 넘지 않는 경우에 SOC 오프셋 추가 제어를 하는 주파수 오프셋 제어부(35)를 포함한다.
여기서, △P는 전력 변동값, △f는 변동 주파수, R은 드룹(Droop) 기울기이다.A system frequency comparison unit 31 that measures the power system frequency and SOC level and compares it with the power system frequency (f) and the upper limit of the frequency control deadband area (f _H ) and the lower limit of the frequency control deadband area (f _{L ), and the system} The SOC level measured according to the comparison result of the frequency comparison unit 31, the SOC overcharge prevention mode division line (SOC _H ), the SOC overdischarge prevention mode division line (SOC _L ), and the SOC control deadband upper limit line (SOC _MH ) and SOC control When the SoC comparison unit 32 that compares the lower limit of the deadband area (SOC _{ML ) and the measured SOC level does not exceed the SOC overcharge prevention mode divider line (SOC H} ) or exceeds the SOC overdischarge prevention mode divider line (SOC _L ) on

If the ESS charge/discharge control unit 33 that controls the ESS charge/discharge and the measured SOC level is between the lower limit of the SOC control deadband area (SOC _ML ) and the upper limit of the SOC control deadband area (SOC _MH ), the power value is zero. (

), and the measured SOC level exceeds the SOC overcharge prevention mode division line (SOC _H ), exceeds the upper limit of the SOC control deadband area (SOC _MH ), or the SOC control deadband area And a frequency offset control unit 35 that performs SOC offset additional control when it does not exceed the lower limit (SOC _ML ) or does not exceed the SOC overdischarge prevention mode division line (SOC _{L ).}
Here, ΔP is the power fluctuation value, Δf is the fluctuation frequency, and R is the droop slope.

Here, the detailed configuration of the system frequency comparison unit 31 is as follows.

4 is a detailed configuration diagram of a system frequency comparison unit according to the present invention.

The grid frequency comparison unit has a first system frequency comparison unit 41 that determines whether the power system frequency f exceeds the upper limit of the frequency control deadband region f _H , and the power system frequency f is the lower limit of the frequency control deadband region. A second system frequency comparison unit 42 that determines whether it is located between (f _L ) and the upper limit of the frequency control deadband area (f _H ), and the power system frequency (f) sets the lower limit of the frequency control deadband area (f _L ). It includes a third system frequency comparison unit 43 to determine whether it is not exceeded.

And the detailed configuration of the SoC comparison unit 32 is as follows.

5 is a detailed configuration diagram of an SOC comparison unit according to the present invention.

The SOC comparison unit exceeds the SOC overcharge prevention mode division line (SOC _H ) when the power system frequency (f) in the first system frequency comparison unit 41 _{exceeds the upper limit of the frequency control deadband area (f H ).} In the first SoC comparison unit 51 and the second system frequency comparison unit 42 to determine whether the power system frequency (f) is the lower limit of the frequency control deadband region (f _L ) and the upper limit of the frequency control deadband region (f _H ), the second SoC comparison unit 52 that determines whether the measured SOC level exceeds the SOC control deadband upper limit (SOC _MH ), and the measured SOC level is the SOC control deadband lower limit (SOC). A third SoC comparison unit 53 that determines whether it is located between the _ML ) and the SOC control deadband upper limit (SOC _MH ), and determines whether the measured SOC level does not exceed the _{SOC control deadband lower limit (SOC ML ).} When the power system frequency (f) in the 4th SoC comparison unit 54 and the 3rd system frequency comparison unit 43 _{exceeds the lower limit of the frequency control deadband area (f L} ), the measured SOC level is the SOC overdischarge prevention mode division line. It includes a fifth SoC comparison unit 55 that determines whether it exceeds (SOC _{L ).}

6 is a state diagram of SoC management and control of the power generation-linked ESS according to the present invention.

It shows the SOC management control state using the offset. In FIG. 6, the SOC level measured by the frequency offset control unit 35 in areas (a) and (b) exceeds the SOC overcharge prevention mode division line (SOC _H ), When the SOC control deadband area upper limit (SOC _MH ) is not exceeded, the SOC control deadband area lower limit (SOC _ML ) is not exceeded, or the SOC overdischarge prevention mode division line (SOC _L ) is not exceeded, additional control of the SOC offset is performed. It is an offset additional control section to be managed.

으로 ESS 충전 제어를 하는 영역이고, (라)영역은 측정된 SOC 레벨이 SOC 과방전 방지 모드 구분선(SOC_L)을 넘는 경우에

으로 ESS 방전 제어를 하는 영역이다.In FIG. 6, the (C) area is when the SOC level measured by the ESS charge/discharge control unit 33 does not exceed the _{SOC overcharge prevention mode division line (SOC H ).}

It is an area that controls ESS charging, and area (D) is when the measured SOC level exceeds the SOC overdischarge prevention mode division line (SOC _L ).

This is an area that controls ESS discharge.

7A and 7B are detailed configuration diagrams of the SoC management control unit of the power generation-linked ESS according to the present invention.

As shown in Fig.7a, for SoC management using frequency tracking control and offset addition of power generation-linked ESS, SoC fluctuation value (△SoC) according to _{the relationship between ESS output (△P ESS} ) and SoC (K _{E: ESS energy)} A SOC change unit 71 that outputs ), and an SOC value conversion unit 72 that converts the SoC fluctuation value into the SoC frequency command value (K _f ) to output the converted value (f _{ofs) for frequency feedback of the SOC, and} , - and a droop (droop) control part 73 for controlling the output ESS _(ESS △ P) as an input to a measuring frequency conversion value] (f-Δf _ofs).

And, as shown in Figure 7b, the SOC reference value change unit 74 for changing the _{measurement frequency (Δf) to the SOC reference value (ΔSoC ref} ) for SoC management using frequency tracking control and offset addition of the power generation-linked ESS, and the ESS SOC change unit 75 that outputs the SoC change value (△SoC) according to the output (△P _ESS ) and the SoC relationship (K _{E : ESS energy), and the SOC reference value (△SoC ref} ) and the SoC change value ( _{The frequency error output unit 76 that converts the} SOC error into a frequency error by inputting △SoC) and the frequency error (Δf-f ofs) of the frequency error output unit 76 are input as an ESS output (△P _ESS ). It includes a droop control unit 73 for controlling.

A detailed description of the SoC management method using the frequency tracking control and offset addition of the power generation-linked ESS according to the present invention is as follows.

8 is a flow chart showing a SoC management method using frequency tracking control and offset addition of a power generation-linked ESS according to the present invention.

으로 ESS 충방전 제어를 하는 ESS 충방전 제어 단계(S810)와, 측정된 SOC 레벨이 SOC 제어 불감대 영역 하한선(SOC_ML)과 SOC 제어 불감대 영역 상한선(SOC_MH) 사이에 위치하면 전력값을 0(

)으로 변경하는 전력값 변경 단계(S811)와, 측정된 SOC 레벨이 SOC 과충전 방지 모드 구분선(SOC_H)을 넘거나, SOC 제어 불감대 영역 상한선(SOC_MH)을 넘거나, SOC 제어 불감대 영역 하한선(SOC_ML)을 넘지 않거나, SOC 과방전 방지 모드 구분선(SOC_L)을 넘지 않는 경우에 SOC 오프셋 추가 제어를 하는 주파수 오프셋 제어 단계(S812)를 포함한다.
여기서, △P는 전력 변동값, △f는 변동 주파수, R은 드룹(Droop) 기울기이다.The SoC management method using the frequency tracking control and offset addition of the power generation-linked ESS according to the present invention largely measures the power system frequency and SOC level (S801), and the power system frequency (f) and the upper limit of the frequency control deadband area (f _H ) And the SOC level measured according to the comparison result of the grid frequency comparison step (S802 to S804) and the grid frequency comparison step compared with the lower limit of the frequency control deadband area (f _{L ) and the SOC overcharge prevention mode divider (SOC H} ), and SoC comparison step (S805 ~ S809) comparing the SOC overdischarge prevention mode division line (SOC _L ) and the SOC control deadband area upper limit (SOC _MH ) and the SOC control deadband area lower limit (SOC _{ML ), and the measured SOC level} When the SOC overcharge prevention mode divider line (SOC _H ) is not exceeded or the SOC overdischarge prevention mode divider line (SOC _L ) is exceeded.

If the ESS charge/discharge control step (S810), which controls ESS charge/discharge, and the measured SOC level is between the lower limit of the SOC control deadband area (SOC _ML ) and the upper limit of the SOC control deadband area (SOC _MH ), the power value is 0(

), the measured SOC level exceeds the SOC overcharge prevention mode division line (SOC _H ), exceeds the upper limit of the SOC control deadband area (SOC _MH ), or the SOC control deadband area And a frequency offset control step (S812) of performing SOC offset additional control when the lower limit (SOC _ML ) is not exceeded or the SOC overdischarge prevention mode division line (SOC _{L) is not exceeded.}
Here, ΔP is the power fluctuation value, Δf is the fluctuation frequency, and R is the droop slope.

By repeating this process, charging and discharging in a predetermined section is completed, and waits until the next cycle.

Here, the grid frequency comparison step includes a first grid frequency comparison step (S802) determining whether the power grid frequency (f) exceeds the frequency control deadband region upper limit (f _H ), and the power grid frequency (f) is frequency controlled. A second system frequency comparison step (S803) of determining whether it is located between the lower limit of the deadband region f _L and the upper limit of the frequency control deadband region f _H , and the power system frequency f is the lower limit of the frequency control deadband region ( f _L ) and a third system frequency comparison step (S804) of determining whether or not it exceeds.

In the SoC comparison step, when the power grid frequency (f) exceeds the upper limit of the frequency control deadband area (f _H ) in the first grid frequency comparison step, the measured SOC level exceeds the SOC overcharge prevention mode division line (SOC _H ). The power system frequency (f) is located between the _{lower limit of the frequency control deadband region (f L} ) and the upper limit of the frequency control deadband region (f _H ) in the determining first SoC comparison step (S805) and the second grid frequency comparison step. In case the measured SOC level exceeds the SOC control deadband area upper limit (SOC _MH ), a second SoC comparison step (S806), and the measured SOC level is the SOC control deadband area lower limit (SOC _ML ) and the SOC A third SoC comparison step (S807) to determine whether it is located between the upper limit of the control deadband region (SOC _MH ) and a fourth SoC comparison to determine whether the measured SOC level does not exceed the _{lower limit of the SOC control deadband region (SOC ML ).} In the step S808 and the third grid frequency comparison step, if the power grid frequency f _{exceeds the lower limit of the frequency control deadband region f L} , whether the measured SOC level exceeds the SOC overdischarge prevention mode division line (SOC _L ). A fifth SoC comparison step (S809) of determining is included.

The SoC management apparatus and method using the frequency tracking control and offset addition of the power generation-linked ESS according to the present invention described above requires that the ESS perform droop control to correct the power system frequency and reduce the power of the ESS after charging or discharging. This is to effectively reduce power by adding an offset rather than changing the power to zero.

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

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

100. Electrical Network
200. Power generation control unit
300. ESS
400. Development Department
500. Power system stabilization unit

Claims (16)

A power generation control unit that senses a change in a frequency of a power system according to a change in output or a load of a generator through an electrical network, and performs automatic power generation control and speed control;
An ESS that is linked to the power generation control unit and the generator and controls the frequency when the power system frequency fluctuates, and then reduces the power value of the ESS by setting an SOC offset, and simultaneously manages the SoC by allowing the AGC operation of the generator to enter without shock;
Including; a power generation unit having a generator that generates power through auxiliary adjustment such as load increase or decrease, or by adjusting the power generation power so that the frequency of the power system maintains the rated frequency through valve control and turbine control,
The ESS is a system frequency comparison unit that measures the power system frequency and SOC level and compares the power system frequency (f) with the upper limit of the frequency control deadband region (f _H ) and the lower limit of the frequency control deadband region (f _{L ),} SOC level measured according to the comparison result of the grid frequency comparison unit, SOC overcharge prevention mode division line (SOC _H ), SOC overdischarge prevention mode division line (SOC _L ), and SOC control deadband area upper limit line (SOC _MH ) and SOC control deadband area SoC management device using the frequency tracking control and offset addition of the power generation-linked ESS, characterized in that it comprises a SoC comparison unit for comparing the lower limit (SOC _ML). The frequency tracking of a power generation-linked ESS according to claim 1, wherein the ESS and the power generation unit communicate with each other in the process of frequency tracking control and SOC offset addition control to perform cooperative control, so that the generator and the ESS share the role of frequency control. SoC management unit with control and offset addition. The method of claim 1, wherein the ESS performs droop control and gradually reduces the power by adding an offset rather than changing the charge/discharge value to 0 when reducing the power value of the ESS after charging or discharging. SoC management device using frequency tracking control and offset addition of power generation-linked ESS, characterized in that recovery management is performed. delete The method of claim 1, wherein the ESS is
When the comparison result of the SoC comparison unit does _{not exceed the SOC overcharge prevention mode division line (SOC H} ) or the SOC overdischarge prevention mode division line (SOC _L ).

It further includes an ESS charge/discharge control unit for controlling the ESS charge/discharge,
△P is the power fluctuation value, △f is the fluctuation frequency, R is the SoC management device using the frequency tracking control and offset addition of the power generation-linked ESS, characterized in that the slope (Droop). The method of claim 1, wherein the ESS is
If the SOC level measured by the comparison result of the SoC comparator is between the lower limit of the SOC control deadband area (SOC _ML ) and the upper limit of the SOC control deadband area (SOC _MH ), the power value is 0 (

) SoC management device using the frequency tracking control and offset addition of the power generation-linked ESS, characterized in that it further comprises a power value change unit to change. The method of claim 1, wherein the ESS is
The SOC level measured by the comparison result of the SoC comparator does not exceed the _{SOC overcharge prevention mode division line (SOC H} ), the SOC control deadband area upper limit (SOC _MH ), or the SOC control deadband area lower limit (SOC _{ML ).} The SoC management device using frequency tracking control and offset addition of a power generation-linked ESS, characterized in that it further comprises a frequency offset control unit that performs SOC offset additional control when the SOC overdischarge prevention mode division line (SOC _{L) is not exceeded.} . The method of claim 1, wherein the system frequency comparison unit,
A first system frequency comparison unit that determines whether the power system frequency (f) exceeds the upper limit of the frequency control deadband region (f _{H );}
A second system frequency comparison unit that determines whether the power system frequency (f) is located between the lower limit of the frequency control deadband region (f _L ) and the upper limit of the frequency control deadband region (f _{H );}
SoC management using frequency tracking control and offset addition of power generation-linked ESS, characterized in that it includes a third system frequency comparison unit that determines whether the power system frequency (f) does not exceed the lower limit of the frequency control deadband area (f _L) Device. The method of claim 1, wherein the SOC comparison unit,
The first SoC comparison unit that determines whether the measured SOC level exceeds the SOC overcharge prevention mode division line (SOC _H ) when the power system frequency (f) exceeds the upper limit of the frequency control deadband area (f _{H) in the system frequency comparison unit.} Wow,
In the grid frequency comparison unit, when the power system frequency (f) is _{located between the lower limit of the frequency control deadband area (f L} ) and the upper limit of the frequency control deadband area (f _H ), the measured SOC level is the upper limit of the SOC control deadband area. A second SoC comparison unit that determines whether it exceeds (SOC _MH),
A third SoC comparison unit that determines whether the measured SOC level is located between the SOC control deadband region lower limit (SOC _ML ) and the SOC control deadband region upper limit (SOC _{MH ),}
A fourth SoC comparison unit that determines whether the measured SOC level does not exceed the SOC control deadband region lower limit (SOC _{ML ),}
In the grid frequency comparison unit, when the power system frequency (f) _{exceeds the lower limit of the frequency control deadband area (f L} ), it includes a fifth SoC comparison unit that determines whether the measured SOC level exceeds the SOC overdischarge prevention mode division line (SOC _{L ).} SoC management device using the frequency tracking control and offset addition of the power generation-linked ESS, characterized in that. The method of claim 1, wherein the ESS is for SoC management using frequency tracking control and offset addition of a power generation-linked ESS,
An SOC change unit that outputs the SoC change value (△SoC) according to the relationship between the ESS output (△P _{ESS) and the SoC, and}
An SOC value conversion unit that converts the SoC fluctuation value into the SoC frequency command value (K _f ) and outputs the converted value (f _{ofs) for frequency feedback of the SOC;}
[Measurement frequency-conversion value] (Δf-f _ofs ) as an input to control the ESS output (△P _ESS ), including a droop control unit for controlling the frequency tracking control and offset of the power generation-linked ESS SoC management device using. The method of claim 1, wherein the ESS is for SoC management using frequency tracking control and offset addition of a power generation-linked ESS,
An SOC reference value change unit that changes the measurement frequency (Δf) to the SOC reference value (△SoC _{ref ),}
An SOC change unit that outputs the SoC change value (△SoC) according to the relationship between the ESS output (△P _{ESS) and the SoC,}
A frequency error output unit that converts the SOC error into a frequency error by inputting the SOC reference value (△SoC _{ref) and the SoC fluctuation value (△SoC),}
Power generation-linked ESS, characterized in that it includes a droop control unit for controlling the ESS output (△P _ESS ) by inputting [measured frequency-conversion value] (Δf-f _{ofs ), which is the frequency error of the frequency error output unit.} SoC management device using frequency tracking control and offset addition of. SoC management method using frequency tracking control and offset addition of power generation-linked ESS is largely by measuring the power system frequency and SOC level,
A system frequency comparison step of comparing the power system frequency (f) with the upper limit of the frequency control deadband region (f _H ) and the lower limit of the frequency control deadband region (f _{L );}
SOC level measured according to the comparison result of the grid frequency comparison step, SOC overcharge prevention mode divider (SOC _H ), SOC overdischarge prevention mode divider (SOC _L ), and SOC control deadband upper limit (SOC _MH ) and SOC control deadband SoC comparison step of comparing the lower region limit (SOC _{ML );}
Measured SOC level does not exceed SOC overcharge prevention mode division line (SOC _H ), SOC control deadband area upper limit (SOC _MH ), SOC control deadband area lower limit (SOC _ML ), or SOC overdischarge prevention A frequency offset control step of performing SOC offset addition control when the mode division line (SOC _L ) is not exceeded; SoC management method using frequency tracking control and offset addition of a power generation-linked ESS. The method of claim 12, wherein the measured SOC level does _{not exceed the SOC overcharge prevention mode division line (SOC H} ) or exceeds the SOC overdischarge prevention mode division line (SOC _L ).

The ESS charge/discharge control step of controlling the ESS charge/discharge is further included,
△P is a power fluctuation value, △f is a fluctuating frequency, R is a droop slope, SoC management method using frequency tracking control and offset addition of the power generation-linked ESS. The power value of claim 12, wherein when the measured SOC level is located between the SOC control deadband region lower limit (SOC _ML ) and the SOC control deadband region upper limit (SOC _MH ), the power value is 0 (

SoC management method using frequency tracking control and offset addition of the power generation-linked ESS, characterized in that it further comprises a step of changing the power value to change to ). The method of claim 12, wherein the step of comparing the grid frequency comprises:
A first system frequency comparison step of determining whether the power system frequency (f) exceeds the upper limit of the frequency control deadband region (f _{H ), and}
A second system frequency comparison step of determining whether the power system frequency (f) is located between the lower limit of the frequency control deadband region (f _L ) and the upper limit of the frequency control deadband region (f _{H );}
SoC using frequency tracking control and offset addition of power generation-linked ESS, characterized in that it includes a third system frequency comparison step that determines whether the power system frequency (f) does not exceed the lower limit of the frequency control deadband area (f _L) Management method. The method of claim 12, wherein the SoC comparison step,
The first SoC comparison step to determine whether the measured SOC level exceeds the SOC overcharge prevention mode division line (SOC _H ) when the power system frequency (f) exceeds the upper limit of the frequency control deadband area (f _{H) in the grid frequency comparison step.} Wow,
In the grid frequency comparison step, when the power grid frequency (f) is _{located between the lower limit of the frequency control deadband region (f L} ) and the upper limit of the frequency control deadband region (f _H ), the measured SOC level is the upper limit of the SOC control deadband region. A second SoC comparison step to determine whether it exceeds (SOC _{MH), and}
A third SoC comparison step of determining whether the measured SOC level is located between the SOC control deadband region lower limit (SOC _ML ) and the SOC control deadband region upper limit (SOC _{MH ),}
A fourth SoC comparison step of determining whether the measured SOC level does not exceed the SOC control deadband region lower limit (SOC _{ML ),}
In the grid frequency comparison step, if the power grid frequency (f) _{exceeds the lower limit of the frequency control deadband area (f L} ), the 5th SoC comparison step to determine whether the measured SOC level exceeds the SOC overdischarge prevention mode division line (SOC _{L ).} SoC management method using the frequency tracking control and offset addition of the power generation-linked ESS comprising a.

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