KR20230069079A - Apparatus for computing inertia of electric power system - Google Patents

Abstract

The present invention includes an input module receiving system information, and a processor connected to the input module, and the processor calculates system inertia of a system in which a renewable energy generator and a general generator are connected based on the system information input through the input module. It is characterized by calculating and outputting the calculated system inertia to be used for frequency stability management of the system.

Description

System inertia calculation device {APPARATUS FOR COMPUTING INERTIA OF ELECTRIC POWER SYSTEM}

The present invention relates to a system inertia calculation device and method.

Many countries, including Korea, are actively promoting the introduction of new and renewable energy sources as a countermeasure against climate change and fossil fuel depletion. Korea is increasing the share of new and renewable energy sources by establishing an implementation plan to increase the share of electricity generation from new and renewable energy sources to 20% of total electricity production by 2030.

In general, generators based on renewable energy sources have an asynchronous characteristic and cannot retain active/reactive power reserves that can be controlled according to system changes. Moreover, inverter-based generators such as solar and wind power cannot provide system inertia, which is essential for maintaining dynamic stability of the system.

In this way, generators based on renewable energy sources are asynchronous, cannot hold reserve power, and do not provide system inertia, unlike existing synchronous generators. Inertia may decrease, and when system inertia decreases, the range of frequency fluctuation of the system due to the occurrence of disturbance increases, which can significantly degrade the stability of the system. In addition, when the frequency fluctuation range of the system greatly increases, a wide-area power outage may occur due to large-scale load shedding due to the operation of an under frequency relay (UFR).

Accordingly, a technique for calculating system inertia in consideration of a generator based on a renewable energy source connected to the system is required to maintain the stability of the system at an appropriate level and prevent wide-area blackouts due to an increase in frequency fluctuation of the system.

The background art of the present invention is disclosed in 'system frequency measuring device and method' of Korean Patent Publication No. 10-2020-0133956 (2020.12.01.).

The present invention was invented to solve the above problems, and an object according to an aspect of the present invention is to provide a system inertia calculation device and method capable of calculating system inertia.

A system inertia calculation device according to an aspect of the present invention includes an input module for receiving system information; and a processor connected to the input module, wherein the processor calculates system inertia of a system in which a renewable energy generator and a general generator are connected based on system information input through the input module, and the system frequency It is characterized in that the calculated system inertia is output to be used for stability management.

In the present invention, the system information is obtained from at least one of EMS (Energy Management System), SCADA (Supervisory Control And Data Acquisition) and TSM (Transmission Security Management System) Status information and facility capacity of the generator linked to the system information, state information and facility capacity information of facilities that affect frequency control of the system, status information and facility capacity information of synchronous ancestors linked to the system, and load information of the system. .

In the present invention, the processor calculates the first system inertia by the generator and the synchronous ancestor connected to the system, calculates the second system inertia by the facility affecting the frequency control of the system, and calculates the calculated first system inertia. and calculating final system inertia based on the second system inertia.

In the present invention, the facilities affecting the frequency control include a generator linked to the governor free, an energy storage system (ESS) for frequency control, and high voltage direct current (HVDC) related facilities. .

In the present invention, the processor is characterized in that the first systemic inertia is calculated through the following formula.

[formula]

는 화력 발전기의 관성지수이고,

는 수력 발전기의 관성지수이고,

는 원자력 발전기의 관성지수이고,

는 인버터 기반 발전기의 관성지수이고,

는 동기조상기의 관성지수이고,

는 계통 부하의 관성지수이고, P_화력은 화력 발전기의 설비용량이고, P_수력은 수력 발전기의 설비용량이고, P_원자력은 원자력 발전기의 설비용량이고, P_IBG는 인버터 기반 발전기의 설비용량이고, P_{동기조상기}는 동기조상기의 설비용량이고, P_load는 계통 부하의 총량이다.)(here,

is the inertia index of the thermal power generator,

is the inertia index of the hydroelectric generator,

is the inertia index of the nuclear power generator,

is the inertia index of the inverter-based generator,

is the inertia index of the synchronous ancestor,

is the inertia index of the grid load, P _{thermal power} is the installed capacity of the thermal power generator, P _hydropower is the installed capacity of the hydroelectric generator, P _{nuclear power} is the installed capacity of the nuclear generator, P _IBG is the installed capacity of the inverter-based generator, and P _{The synchronous ancestor} is the installed capacity of the synchronous ancestor, and P _load is the total load of the system.)

In the present invention, the processor is characterized in that the second systemic inertia is calculated through the following formula.

[formula]

는 발전기에 연계된 조속기의 관성지수이고,

는 주파수조정용 ESS의 관성지수이고,

는 HVDC 관련 설비의 관성지수이고, P_GF는 발전기의 운전 예비력이고, P_ESS는 주파수조정용 ESS의 설비용량이고, P_HVDC는 HVDC 관련 설비의 운전 예비력이다.)(here,

is the inertia index of the governor connected to the generator,

Is the inertia index of the ESS for frequency adjustment,

is the inertia index of the HVDC-related facility, P _GF is the operating reserve power of the generator, P _ESS is the facility capacity of the frequency control ESS, and P _HVDC is the operating reserve power of the HVDC-related facility.)

In the present invention, the processor is characterized in that it calculates the operating reserve power of the generator and the operating reserve force of the HVDC-related facility through the following formula.

[formula]

은 출력중인 모든 발전기의 설비용량이고,

는 출력중인 모든 발전기의 출력량이고,

는 HVDC 관련 설비의 설비용량이고,

는 HVDC 관련 설비의 출력량이다.)(here,

is the installed capacity of all generators in output,

is the output of all generators in output,

is the installed capacity of HVDC-related facilities,

is the output of HVDC-related facilities.)

In the present invention, the processor is characterized in that the final system inertia is calculated by adding the calculated first system inertia and the calculated second system inertia.

In the present invention, the processor is characterized in that it calculates a system constant based on the calculated system inertia and outputs the calculated system constant.

In the present invention, the processor is characterized in that the system constant is calculated through the following formula.

[formula]

(Here, I _Total is the calculated systemic inertia, A is a conversion index for converting systemic inertia into a system constant, and is a value input through the input module.)

In the present invention, the processor compares the calculated system inertia with a preset reference system inertia to determine whether the calculated system inertia is less than or equal to the reference system inertia, and determines whether the calculated system inertia is less than or equal to the reference system inertia. When it is determined that it is characterized by outputting a warning signal.

A system inertia calculation method according to an aspect of the present invention includes receiving, by a processor, system information through an input module; calculating, by the processor, system inertia of a system in which a renewable energy generator and a general generator are linked based on the received system information; and outputting, by the processor, the calculated system inertia to be used for frequency stability management of the system.

In the present invention, the system information is obtained from at least one of EMS (Energy Management System), SCADA (Supervisory Control And Data Acquisition) and TSM (Transmission Security Management System) Status information and facility capacity of the generator linked to the system information, state information and facility capacity information of facilities that affect frequency control of the system, status information and facility capacity information of synchronous ancestors linked to the system, and load information of the system. .

In the present invention, the calculating step may include calculating, by the processor, a first system inertia by a generator and a synchronous ancestor connected to the system; calculating, by the processor, a second system inertia by a facility that affects frequency control of the system; and calculating, by the processor, final systemic inertia based on the calculated first and second systemic inertia.

The facility influencing the frequency control is characterized in that it includes a generator associated with a governor free, an energy storage system (ESS) for frequency control, and a high voltage direct current (HVDC) related facility.

In the step of calculating the first systemic inertia in the present invention, the processor calculates the first systemic inertia through the following formula.

[formula]

는 화력 발전기의 관성지수이고,

는 수력 발전기의 관성지수이고,

는 원자력 발전기의 관성지수이고,

는 인버터 기반 발전기의 관성지수이고,

는 동기조상기의 관성지수이고,

는 계통 부하의 관성지수이고, P_화력은 화력 발전기의 설비용량이고, P_수력은 수력 발전기의 설비용량이고, P_원자력은 원자력 발전기의 설비용량이고, P_IBG는 인버터 기반 발전기의 설비용량이고, P_{동기조상기}는 동기조상기의 설비용량이고, P_load는 계통 부하의 총량이다.)(here,

is the inertia index of the thermal power generator,

is the inertia index of the hydroelectric generator,

is the inertia index of the nuclear power generator,

is the inertia index of the inverter-based generator,

is the inertia index of the synchronous ancestor,

is the inertia index of the grid load, P _{thermal power} is the installed capacity of the thermal power generator, P _hydropower is the installed capacity of the hydroelectric generator, P _{nuclear power} is the installed capacity of the nuclear generator, P _IBG is the installed capacity of the inverter-based generator, and P _{The synchronous ancestor} is the installed capacity of the synchronous ancestor, and P _load is the total load of the system.)

In the step of calculating the second systemic inertia in the present invention, the processor calculates the second systemic inertia through the following formula.

[formula]

는 발전기에 연계된 조속기의 관성지수이고,

는 주파수조정용 ESS의 관성지수이고,

는 HVDC 관련 설비의 관성지수이고, P_GF는 발전기의 운전 예비력이고, P_ESS는 주파수조정용 ESS의 설비용량이고, P_HVDC는 HVDC 관련 설비의 운전 예비력이다.)(here,

is the inertia index of the governor connected to the generator,

Is the inertia index of the ESS for frequency adjustment,

is the inertia index of the HVDC-related facility, P _GF is the operating reserve power of the generator, P _ESS is the facility capacity of the frequency control ESS, and P _HVDC is the operating reserve power of the HVDC-related facility.)

In the present invention, the processor is characterized in that it calculates the operating reserve power of the generator and the operating reserve force of the HVDC-related facility through the following formula.

[formula]

은 출력중인 모든 발전기의 설비용량이고,

는 출력중인 모든 발전기의 출력량이고,

는 HVDC 관련 설비의 설비용량이고,

는 HVDC 관련 설비의 출력량이다.)(here,

is the installed capacity of all generators in output,

is the output of all generators in output,

is the installed capacity of HVDC-related facilities,

is the output of HVDC-related facilities.)

In the present invention, in the step of calculating the final system inertia, the processor calculates the final system inertia by adding the calculated first system inertia and the calculated second system inertia.

Calculating, by the processor, a system constant based on the calculated system inertia in the present invention; and outputting, by the processor, the calculated systematic constant.

In the step of calculating the systematic constant in the present invention, the processor calculates the systematic constant through the following formula.

[formula]

(Here, I _Total is the calculated systemic inertia, A is a conversion index for converting systemic inertia into a system constant, and is a value input through the input module.)

In the present invention, the step of determining, by the processor, whether the calculated systemic inertia is equal to or less than the reference systemic inertia by comparing the calculated systemic inertia with a preset reference systemic inertia; and outputting, by the processor, a warning signal when it is determined that the calculated systemic inertia is less than or equal to the reference systemic inertia.

According to an aspect of the present invention, system inertia of a system connected to a renewable energy generator may be calculated, and the calculated system inertia may be output to be used for frequency stability management of the system.

According to another aspect of the present invention, by calculating system inertia and providing it to the user, uncertainty in system frequency management can be reduced, costs required for securing reserve power for system frequency adjustment can be reduced, and wide-area blackout and It can contribute to the stable operation of the system by predicting and preventing system collapse in advance.

1 is a conceptual diagram of the equal area method, which is one of the methods for determining the transient stability of the system.
2 is a conceptual diagram of an infinite bus system of one generator.
3 is an exemplary diagram showing a frequency change over time of a system when a failure occurs.
4 is an equivalent circuit of a ZIP model structure used to express a load model.
5 is a block configuration diagram for explaining a system inertia calculator of a system according to an embodiment of the present invention.
6 is a flowchart illustrating a system inertia calculation method of a system according to an embodiment of the present invention.
7 is a flowchart for explaining a process after calculating system inertia through a system inertia calculation method according to an embodiment of the present invention.

Hereinafter, a system inertia calculating device and method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this process, the thickness of lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, terms to be described later are terms defined in consideration of functions in the present invention, which may vary according to the intention or custom of a user or operator. Therefore, definitions of these terms will have to be made based on the content throughout this specification.

1 is a conceptual diagram related to the equal area method, which is one of the methods for determining the transient stability of the system, FIG. 2 is a conceptual diagram of an infinite bus system of one generator, and FIG. 3 is a frequency change over time in the system when a failure occurs. It is an example diagram showing .

Hereinafter, the need for system inertia calculation will be described with reference to FIGS. 1 to 3 .

As inverter-based renewable generators are connected to the grid, the ratio of synchronous generators is relatively low, which leads to a decrease in grid inertia. Due to the decrease in system inertia, the change width of generator angular velocity can be increased in case of disturbance. The above can be grasped through the fluctuation equation described in Equation 1 below.

는 발전기의 위상각이고,

는 발전기의 기존 각속도이고,

는 발전기의 변화된 각속도이고,

는 시간이고,

는 관성계수이고,

는 발전기의 기계적 입력이고,

는 발전기의 전기적 출력일 수 있다. here,

is the phase angle of the generator,

is the original angular velocity of the generator,

is the changed angular velocity of the generator,

is time,

is the coefficient of inertia,

is the mechanical input of the generator,

may be the electrical output of the generator.

)이고, 임계고장제거 위상각에 도달하는 시간은 CCT(Critical Clearing Time)로 정의될 수 있다.Referring to FIG. 1 , the equal area method is a concept in which the generator stably operates after a disturbance if the deceleration area A2 is larger than the acceleration area A1 in the electrical output graph for the generator phase angle. The phase angle of the generator that makes the acceleration area and deceleration area equal is the Critical Clearing Angle (Critical Clearing Angle).

), and the time to reach the critical fault clearing phase angle can be defined as CCT (Critical Clearing Time).

Referring to FIG. 2, it is possible to determine the correlation between the generator's coefficient of inertia and the CCT by simulating a three-phase ground fault situation generated in the infinite bus system of the first generator.

Integrating each of the fluctuation equations described in Equation 1 above can be expressed as Equation 2 below.

Through Equation 2 above, it can be seen theoretically that the inertia coefficient is inversely proportional to the change in the phase angle. In other words, as the proportion of new and renewable power generation increases, the inertia coefficient decreases, and when a disturbance occurs in the system, the critical fault elimination phase angle is reached more quickly, which can mean that the transient stability and frequency stability of the system decrease. there is.

Referring to FIG. 3 , unlike existing synchronous generators, in the case of a system with a high proportion of inverter-based new and renewable generators having no rotational inertia, system inertia is lower than that of other systems. In Korea, in order to prevent blackout, when the frequency drops above a certain level, the load is dropped through a low-frequency relay (UFR) to operate the system stably. It can be seen that the frequency reaches 59Hz faster. In the case of a system with low system inertia, the operation frequency of the low-frequency relay is reached faster than in the case of a system with low system inertia. A lot of frequency reserve resources need to be secured.

4 is an equivalent circuit of a ZIP model structure used to express a load model.

Referring to FIG. 4 , a general load in a steady state may be expressed as an equivalent circuit (including a constant impedance model, a constant current model, and a constant power model) of a ZIP model structure. The constant impedance model can express a load maintaining a constant impedance, and when the voltage fluctuates, the load value of the constant impedance model is proportional to the square of active/reactive power. The constant current model can express a load through which a constant current flows, and when the voltage fluctuates, the load value of the constant current model is proportional to active/reactive power. The constant power model can express a load that always consumes constant power, and the load value of the constant power model is always constant regardless of voltage. The load model described above can be expressed as in Equation 3 below. The present invention can calculate the total load of the system through the load model described above, which can be used in the process of calculating the first system inertia described later.

이면 정전력이고,

이면 정전류이고,

이면 정임피던스이고,

은 전체 부하전력이고,

은 정전력의 부하값이고,

는 정전류의 부하값이고,

은 정임피던스의 부하값이고,

는 전압이고,

은 초기전압일 수 있다.here,

is the electrostatic force,

is a constant current,

is the constant impedance,

is the total load power,

is the load value of the static power,

is the load value of the constant current,

is the load value of the constant impedance,

is the voltage,

may be an initial voltage.

5 is a block configuration diagram for explaining a system inertia calculator of a system according to an embodiment of the present invention.

Referring to FIG. 5 , the system inertia calculation device of a system according to an embodiment of the present invention may include an input module 100 , an output module 200 and a processor 300 .

The input module 100 may receive system information. The input module 100 may receive various data necessary for the processor 300 to calculate the system inertia of the system from the outside and transmit them to the processor 300 . According to one embodiment, the system information is the state information and facility capacity information of the generator associated with the system obtained from at least one of EMS (Energy Management System), SCADA (Supervisory Control And Data Acquisition) and TSM (Transmission Security Management System) and facility status information and facility capacity information affecting frequency control of the system, status information and facility capacity information of the synchronous ancestor linked to the system, and load information of the system.

The output module 200 outputs various data calculated in the process of the processor 300 calculating the system inertia of the system under the control of the processor 300 described later, or the processor 300 calculates the system inertia of the system. You can print the result.

The processor 300 calculates the system inertia of a system in which a renewable energy generator and a general generator are connected based on the system information received through the input module 100, and the system of the system calculated to be used for frequency stability management of the system. Inertia can be output.

Hereinafter, a process of calculating system inertia by the processor 300 will be described.

First, the processor 300 may receive system information through the input module 100 . The processor 300 may receive system information through the input module 100 at a preset cycle to calculate system inertia at a preset cycle.

Subsequently, the processor 300 may calculate a first system inertia by the generator and the synchronous ancestor connected to the system based on the system information received through the input module 100 .

는 화력 발전기의 관성지수이고,

는 수력 발전기의 관성지수이고,

는 원자력 발전기의 관성지수이고,

는 인버터 기반 발전기의 관성지수이고,

는 동기조상기의 관성지수이고,

는 계통 부하의 관성지수이고, P_화력은 화력 발전기의 설비용량이고, P_수력은 수력 발전기의 설비용량이고, P_원자력은 원자력 발전기의 설비용량이고, P_IBG는 인버터 기반 발전기의 설비용량이고, P_{동기조상기}는 동기조상기의 설비용량이고, P_load는 계통 부하의 총량일 수 있다. 이때,

는 2~6[s]일 수 있고,

는

보다 작은 값일 수 있다. 각 발전기의 관성지수는 입력 모듈(100)을 통해 입력받은 발전기의 상태 정보에 포함되어 있을 수 있고, 동기조상기의 관성지수는 입력 모듈(100)을 통해 입력받은 동기조상기의 상태 정보에 포함되어 있을 수 있다.According to an embodiment, the processor 300 may calculate the first system inertia of the system through Equation 4 above. Here, I _PS is the first system inertia of the system,

is the inertia index of the thermal power generator,

is the inertia index of the hydroelectric generator,

is the inertia index of the nuclear power generator,

is the inertia index of the inverter-based generator,

is the inertia index of the synchronous ancestor,

is the inertia index of the grid load, P _{thermal power} is the installed capacity of the thermal power generator, P _hydropower is the installed capacity of the hydroelectric generator, P _{nuclear power} is the installed capacity of the nuclear generator, P _IBG is the installed capacity of the inverter-based generator, and P _{Synchronous ancestor} may be the installed capacity of the synchronizing ancestor, and P _load may be the total load of the system. At this time,

may be 2 to 6 [s],

Is

may be a smaller value. The inertia index of each generator may be included in the state information of the generator input through the input module 100, and the inertia index of the synchronous ancestor may be included in the state information of the synchronous ancestor input through the input module 100. can

는 계통에 연계되어 운전 중인 모든 화력 발전기의 설비용량의 합이고,

는 계통에 연계되어 운전 중인 모든 수력 발전기의 설비용량의 합이고,

는 계통에 연계되어 운전 중인 모든 원자력 발전기의 설비용량의 합이고,

는 계통에 연계되어 운전 중인 모든 인버터 기반 발전기의 설비용량의 합이고,

는 계통에 연계되어 운전 중인 모든 동기조상기의 설비용량의 합일 수 있다.

is the sum of the installed capacities of all thermal power generators operating in connection with the system,

is the sum of the installed capacities of all hydroelectric generators operating in connection with the grid,

is the sum of the installed capacities of all nuclear power generators operating in connection with the grid,

is the sum of the installed capacities of all inverter-based generators operating in connection with the grid,

may be the sum of the installed capacities of all synchronous ancestors operating in connection with the system.

That is, the processor 300 may calculate the system inertia by the generator and the synchronous ancestor among various facilities linked to the system as the first system inertia. Here, the generator includes a renewable energy generator including a hydroelectric generator and an inverter-based generator (eg, a solar power generator and a wind generator, etc.), and a general generator including a thermal power generator and a nuclear power generator. can do. However, it is not limited to the above-described embodiment, and various types of generators that can be connected to the system may be considered when calculating the first system inertia.

가 적용됨), 발전기의 종류가 동일하더라도 다른 관성지수가 적용될 수도 있다.(예를 들어, 화력 발전기1의 경우 관성지수

이 적용되고, 화력 발전기2의 경우 관성지수

가 적용될 수 있다.) 즉, 관성 지수를 보다 세부적으로 적용함으로써 연산의 정확도를 향상시킬 수 있다. 이 경우, 각 발전기에 대응하는 관성지수가 입력 모듈(100)을 통해 입력될 수 있다.On the other hand, in the above-described embodiment, it is described that the same inertia index is applied when the type of generator is the same (for example, in the case of a thermal power generator, the inertia index

is applied), and even if the type of generator is the same, a different inertia index may be applied. (For example, in the case of thermal power generator 1, the inertia index

is applied, and in the case of thermal power generator 2, the inertia index

may be applied.) That is, the accuracy of calculation may be improved by applying the inertia index in more detail. In this case, the inertia index corresponding to each generator may be input through the input module 100 .

Subsequently, the processor 300 may calculate a second system inertia by a facility affecting frequency control of the system based on the system information received through the input module 100 .

는 발전기에 연계된 조속기(Governor Free)의 관성지수이고,

는 주파수조정용 ESS(Energy Storage System)의 관성지수이고,

는 HVDC(High Voltage Direct Current) 관련 설비의 관성지수이고, P_GF는 발전기의 운전 예비력이고, P_ESS는 주파수조정용 ESS의 설비용량이고, P_HVDC는 HVDC 관련 설비의 운전 예비력일 수 있다. 이때,

는 50~150[s]일 수 있다.According to an embodiment, the processor 300 may calculate the second system inertia of the system through Equation 5 above. Here, I _GF is the second systemic inertia of the system,

is the inertia index of the governor-free connected to the generator,

Is the inertia index of the ESS (Energy Storage System) for frequency adjustment,

Is the inertia index of HVDC (High Voltage Direct Current) related facilities, P _GF is the operating reserve of the generator, P _ESS is the facility capacity of the frequency control ESS, and P _HVDC may be the operating reserve of the HVDC related facility. At this time,

may be 50 to 150 [s].

는 계통에 연계되어 운전 중인 모든 발전기의 운전 예비력의 합이고,

는 계통에 연계되어 운전 중인 모든 주파수조정용 ESS의 설비용량의 합이고,

는 계통에 연계되어 운전 중인 모든 HVDC 관련 설비의 운전 예비력의 합일 수 있다.

is the sum of the operating reserve power of all generators operating in connection with the grid,

is the sum of the installed capacities of all frequency control ESSs operating in connection with the grid,

may be the sum of the operating reserve power of all HVDC-related facilities in operation in connection with the grid.

은 출력중인 모든 발전기의 설비용량이고,

는 출력중인 모든 발전기의 출력량일 수 있다. 발전기의 출력량은 발전기의 상태 정보에 포함되어 있을 수 있다. 프로세서(300)는

이고, 발전기가 Inservice(병입된 상태)인 경우 제2 계통관성의 연산 시 앞서 산출된 P_GF를 고려하고, 전술한 조건을 만족하지 못하는 경우 제2 계통관성의 연산 시 P_GF값을 0으로 처리할 수 있다. The operating reserve power of the generator can be calculated by subtracting the output of the generator being output from the installed capacity of the generator being output. The processor 300 may calculate the operating reserve power of the generator through Equation 6 above. here,

is the installed capacity of all generators in output,

may be the amount of output of all generators in output. The output amount of the generator may be included in the state information of the generator. Processor 300

, and when the generator is in service (fed-in), the previously calculated P _GF is considered when calculating the second system inertia, and if the above conditions are not satisfied, the P _GF value is treated as 0 when calculating the second system inertia. can do.

On the other hand, since the operating reserve power of the generator is generally set to a constant value during system operation, instead of calculating the operating reserve power of the generator through Equation 6, the processor 300 uses the input module 100 to externally (for example, , The user or the server) may directly receive the operating reserve power of the generator, and calculate the second system inertia using the received operating reserve force of the generator.

는 HVDC 관련 설비의 설비용량이고,

는 HVDC 관련 설비의 출력량일 수 있다. HVDC 관련 설비의 출력량은 설비의 상태 정보에 포함되어 있을 수 있다. 프로세서(300)는

이고, 발전기가 Inservice(병입된 상태)인 경우 제2 계통관성의 연산 시 앞서 산출된 P_HVDC를 고려하고, 전술한 조건을 만족하지 못하는 경우 제2 계통관성의 연산 시 P_HVDC를 0으로 처리할 수 있다. The operating reserve power of the HVDC-related facility may be calculated by subtracting the output of the HVDC-related facility from the facility capacity of the HVDC-related facility. The processor 300 may calculate the operating reserve of the HVDC-related facility through Equation 7 above. here,

is the installed capacity of HVDC-related facilities,

may be an output amount of an HVDC-related facility. The amount of output of the HVDC-related facility may be included in the state information of the facility. Processor 300

And, when the generator is in service (fed-in state), the previously calculated P _HVDC is considered when the second system inertia is calculated, and when the above conditions are not satisfied, P _HVDC is treated as 0 when the second system inertia is calculated. can

That is, the processor 300 may calculate, as the second system inertia, system inertia by a facility influencing frequency control of the system among various facilities linked to the system. Here, the facilities affecting the frequency control of the system may include a generator linked with a governor, an ESS for frequency adjustment, and HVDC related facilities. However, it is not limited to the above-described embodiment, and various types of facilities that can be linked to the system for frequency control of the system may be considered when calculating the second system inertia.

가 적용됨), 설비의 종류가 동일하더라도 다른 관성지수가 적용될 수도 있다. 즉, 관성 지수를 보다 세부적으로 적용함으로써 연산의 정확도를 향상시킬 수 있다. 이 경우, 각 설비에 대응하는 관성지수가 입력 모듈(100)을 통해 입력될 수 있다.On the other hand, in the above-described embodiment, it is described that the same inertia index is applied when the type of equipment is the same (for example, in the case of a governor connected to a generator, the inertia index

is applied), and even if the type of facility is the same, a different inertia index may be applied. That is, the accuracy of calculation can be improved by applying the inertia index in more detail. In this case, an index of inertia corresponding to each facility may be input through the input module 100 .

Then, the processor 300 may calculate the final system inertia of the system based on the previously calculated first and second system inertia.

According to an embodiment, the processor 300 may calculate the final system inertia by adding the previously calculated first and second system inertia. That is, the processor 300 may calculate the final system inertia of the system through Equation 8 above.

Subsequently, the processor 300 may output the calculated final system inertia to the outside through the output module 200 to be used for frequency stability management of the system. Meanwhile, the processor 300 may output first system inertia and second system inertia as well as the final system inertia of the system.

As described above, the present invention can calculate the system inertia of the system to which the renewable energy generator is connected, and output the calculated system inertia to be used for frequency stability management of the system. In addition, the present invention calculates system inertia and provides it to the user, thereby reducing uncertainty in frequency management of the system and reducing the cost required for securing reserve power for frequency adjustment of the system. It can contribute to the stable operation of the system by predicting and preventing collapse in advance.

Meanwhile, after calculating the system inertia of the system, the processor 300 may calculate the system constant of the system based on the calculated system inertia and output the calculated system constant.

)이고, 그 단위는 [MW/Hz]이고, A는 계통관성을 계통정수로 환산하기 위한 환산 지수로서, 그 단위는 [Hz/s]일 수 있다. 계통관성을 계통정수로 환산하기 위한 환산 지수는 입력 모듈(100)을 통해 입력될 수 있으며, 각 계통에 대응하는 환산 지수는 주파수 변동에 따른 계통의 전력 변동에 대한 데이터를 누적분석하여 산출할 수 있다.According to an embodiment, the processor 300 may calculate the system constant of the system through Equation 9 above. Here, I _Total is the system inertia of the system, K is the system constant of the system, and is an index representing the power variation of the system according to the system frequency variation (i.e.,

), its unit is [MW/Hz], A is a conversion index for converting system inertia into a system constant, and its unit may be [Hz/s]. A conversion index for converting system inertia into a system constant may be input through the input module 100, and a conversion index corresponding to each system may be calculated by cumulatively analyzing data on power fluctuation of the system according to frequency fluctuation. there is.

Meanwhile, after calculating the system inertia of the system, the processor 300 compares the calculated system inertia with a preset reference system inertia to determine whether the calculated system inertia is equal to or less than the reference system inertia, and determines whether the calculated system inertia is the reference system inertia. A warning signal can be output if it is judged to be less than the system inertia. According to an embodiment, the processor 300 may compare the first hierarchical relationship with the reference hierarchical relationship, or may compare the final hierarchical relationship with the reference hierarchical relationship. According to an embodiment, when it is determined that the calculated systemic inertia is less than or equal to the reference systemic inertia, the processor 300 may output a warning signal through a human machine interface (HMI).

6 is a flowchart illustrating a system inertia calculation method of a system according to an embodiment of the present invention.

Hereinafter, with reference to FIG. 6, a system inertia calculation method of a system according to an embodiment of the present invention will be described.

First, the processor 300 may receive system information through the input module 100 (step S100).

Subsequently, the processor 300 may calculate the first system inertia by the generator and the synchronous ancestor connected to the system based on the system information received through the input module 100 (step S200).

Next, the processor 300 may calculate the second system inertia by facilities that affect frequency control of the system based on the system information received through the input module 100 (step S300).

Subsequently, the processor 300 may calculate the final system inertia of the system based on the calculated first and second system inertia (step S400). The processor 300 may calculate the final system inertia by adding the calculated first system inertia and the second system inertia.

Subsequently, the processor 300 may output the calculated final system inertia to the outside through the output module 200 to be used for frequency stability management of the system. The processor 300 may output first and second system inertia as well as the final system inertia of the system (step S500).

7 is a flowchart for explaining a process after calculating system inertia through a system inertia calculation method according to an embodiment of the present invention.

First, the processor 300 may compare the calculated systemic inertia with a preset reference systemic inertia to determine whether the calculated systemic inertia is equal to or less than the standard systemic inertia (step S600).

When it is determined that the calculated system inertia is less than or equal to the reference system inertia, the processor 300 may output a warning signal (step S700). The processor 300 may output a warning signal through a human machine interface (HMI).

As described above, the system inertia calculation apparatus and method according to an embodiment of the present invention calculates the system inertia of a system connected to a renewable energy generator, and outputs the calculated system inertia to be used for frequency stability management of the system. can In addition, the present invention calculates system inertia and provides it to the user, thereby reducing uncertainty in frequency management of the system and reducing the cost required for securing reserve power for frequency adjustment of the system. It can contribute to the stable operation of the system by predicting and preventing collapse in advance.

Implementations described herein may be embodied in, for example, a method or process, an apparatus, a software program, a data stream, or a signal. Even if discussed only in the context of a single form of implementation (eg, discussed only as a method), the implementation of features discussed may also be implemented in other forms (eg, an apparatus or program). The device may be implemented in suitable hardware, software and firmware. The method may be implemented in an apparatus such as a processor, which is generally referred to as a processing device including, for example, a computer, microprocessor, integrated circuit or programmable logic device or the like. Processors also include communication devices such as computers, cell phones, personal digital assistants ("PDAs") and other devices that facilitate communication of information between end-users.

Although the present invention has been described with reference to the embodiments shown in the drawings, it should be noted that this is only exemplary and various modifications and equivalent other embodiments are possible from those skilled in the art to which the technology pertains. will understand Therefore, the true technical protection scope of the present invention should be defined by the claims below.

100: input module
200: output module
300: processor

Claims (1)

An input module for receiving system information; and
Including; a processor connected to the input module;
The processor calculates system inertia of a system in which a renewable energy generator and a general generator are connected based on system information input through the input module, and outputs the calculated system inertia to be used for frequency stability management of the system. do,
The processor calculates a first system inertia by a generator and a synchronous ancestor connected to the system, calculates a second system inertia by a facility affecting frequency control of the system, and calculates the calculated first and second system inertia. 2 Calculate final system inertia based on system inertia,
The processor calculates the final system inertia by adding the calculated first system inertia and the calculated second system inertia;
Facilities influencing the frequency control include a generator connected to a governor free, an energy storage system (ESS) for frequency regulation, and high voltage direct current (HVDC) related facilities,
The system information includes state information and facility capacity information of a generator connected to the system obtained from at least one of an energy management system (EMS), a supervisory control and data acquisition (SCADA), and a transmission security management system (TSM), and the Including status information and facility capacity information of facilities that affect frequency control of the system, status information and facility capacity information of the synchronous ancestor linked to the system, and load information of the system,
The processor compares the calculated system inertia with a preset reference system inertia to determine whether the calculated system inertia is equal to or less than the reference system inertia, and when it is determined that the calculated system inertia is less than or equal to the reference system inertia. System inertia calculation device characterized in that for outputting a warning signal.

Images