KR20210034303A - EVALUATION METHOD and SYSTEM OF POWER NETWORK RELIABILITY - Google Patents

Abstract

The present invention provides a method for evaluating reliability of a power grid based on a frequency variation model which can quickly and accurately monitor the power grid having renewable energy. The method for evaluating reliability of a power grid based on a frequency variation model comprises the steps of: constructing a power grid model; configuring a scenario for power operation for a predetermined period; estimating a frequency change of power in the scenario; and performing reliability evaluation based on the frequency change and determining that an evaluation result is reliable if the evaluation result exceeds a reference value.

Description

Power grid reliability evaluation method and system {EVALUATION METHOD and SYSTEM OF POWER NETWORK RELIABILITY}

The present invention relates to a power grid reliability evaluation method that can quickly and accurately monitor a power grid equipped with renewable energy and a power grid evaluation system that performs the same.

In general power grid planning, the power supply configuration for the balance of supply and demand is the top priority, and the generator capacity is calculated by reflecting only the failure and shutdown conditions of the main power facilities. For example, it is used as a power grid reliability index by reflecting an indicator such as LOLP (Loss of Load Probability).

However, in a situation where concerns about the stability of the power grid are increasing due to the recent increase in the introduction of distributed power sources such as new and renewable energy, there are many difficulties in planning the power grid using the existing reliability index. Unlike existing traditional generators, new and renewable energy is an energy resource with very high volatility, so measures must be taken to maintain stability, such as reserves, within a very short time.

However, the existing reliability indices are made based on a steady state in a long time domain, so it is not appropriate to evaluate the stability of a power source with high volatility such as a renewable energy source in a transient state. In order to evaluate the reserve power level due to volatility of new and renewable energy and to evaluate the adequacy of the power supply configuration of the planned DB, a new indicator that can evaluate the adequacy of the power supply configuration due to short-term volatility is required.

Republic of Korea Registered Gazette No. 10-1543303

An object of the present invention is to provide a power grid reliability evaluation system capable of quickly and accurately monitoring a power grid equipped with renewable energy.

Specifically, in the present invention, a new short-term reliability evaluation model based on probability and statistics and a new short-term reliability evaluation model based on probability and statistics through an iterative review process designating the frequency of the power grid representing the dynamic characteristics of the power grid as a target of interest is proposed. do.

A method for evaluating power grid reliability according to an aspect of the present invention includes the steps of constructing a power grid model; Configuring a scenario for power operation for a predetermined period; Estimating a frequency change of power in the scenario; And performing reliability evaluation based on the frequency change and determining that the evaluation result is reliable if the evaluation result exceeds a reference value.

Here, if the reliability evaluation result does not exceed the reference value, the power grid configuration may be adjusted to return to the power grid model configuration step.

Here, the step of acquiring power grid information for configuring a power grid model may be further included, and if the reliability evaluation result does not exceed a reference value, only those of the power grid information that can be changed during operation may be adjusted and returned.

Here, in the power grid construction step, a general synchronous generator power generation part, a renewable energy resource, a reserve power limitation, and a load may be considered as variable components.

Here, in the power generation part of a general synchronous generator, a prime mover element and a governor element can be considered.

In this case, the scenario configuration step and the frequency change estimation step are performed for a plurality of scenarios, and in each of the scenarios, changes in new renewable energy and load may be set differently.

Here, in the frequency change estimation step, the frequency change can be checked according to the following equation.

: 신재생에너지와 부하의 변동성, (

: Renewable energy and load volatility,

T _p : Time constant of the prime mover expressed by the equivalent model,

T _g : Time constant of the governor expressed by the equivalent model,

: 주파수 변화 출력R _eq : system speed adjustment rate,

: Frequency change output

M _eq : equivalent system system inertia, D _eq : load equivalent damping factor)

Here, in the step of determining that the frequency change is reliable, the frequency change may be determined according to a frequency-based reliability index of the power grid maintaining a predetermined'probability level approximating 1'in the range of the allowable width relative to the rated frequency.

Here, in the step of determining that it is reliable, the frequency change is defined according to the following equation, and the frequency change is based on the frequency-based reliability index of the power grid maintaining a range of ±0.1 Hz or ±0.2 Hz relative to the rated frequency at a level of 99.99%. You can judge accordingly.

(N: number of frequency samples,

:

개의 주파수 샘플을 갖는 집단에서의 표준편차,

:

Standard deviation in a population of 4 frequency samples,

FI: frequency-based reliability index)

A system for evaluating power grid reliability according to another aspect of the present invention includes: an input unit for obtaining power grid information for configuring a power grid model; A modeling unit that generates a power grid model capable of reflecting frequency fluctuation characteristics using the power grid information; A scenario construction unit for creating two or more scenarios that can apply at least one of a new renewable energy generation amount and a power grid load to the generated power grid model; A scenario execution unit that executes each of the created scenarios and collects the results; A result processing unit that performs statistical processing on the collected results; A determination unit that determines the reliability of the power grid from the statistical processing result; A display unit for displaying the determined power grid reliability; And a power grid adjustment unit that changes part of the power grid information when the determined power grid reliability is insufficient.

Here, the modeling unit may generate a model by considering a power generation part of a general synchronous generator, a renewable energy resource, a reserve power limitation, and a load as a variable component.

Here, the scenario construction unit creates a plurality of scenarios in which variations on the new and renewable energy and the load are set differently, and the scenario execution unit may estimate a frequency change due to the variation on the new and renewable energy and the load.

Here, the scenario execution unit may check the frequency change according to the following equation.

: 신재생에너지와 부하의 변동성, (

: Renewable energy and load volatility,

T _p : Time constant of the prime mover expressed by the equivalent model,

T _g : Time constant of the governor expressed by the equivalent model,

: 주파수 변화 출력R _eq : system speed adjustment rate,

: Frequency change output

M _eq : equivalent system system inertia, D _eq : load equivalent damping factor)

Here, the determination unit may determine the range of the allowable width relative to the rated frequency according to the frequency-based reliability index of the power grid maintaining a predetermined'probability level approximating 1'.

If the power grid reliability evaluation system based on the frequency fluctuation model of the present invention according to the above-described configuration is implemented, there is an advantage in that it is possible to quickly and accurately monitor a power grid equipped with renewable energy.

1 is a flowchart illustrating an embodiment of a method for evaluating power grid reliability based on a frequency fluctuation model according to the idea of the present invention.
FIG. 2 is a mathematical equivalent block diagram of a power grid model configured in the power grid reliability evaluation method of FIG. 1.
FIG. 3 is a block diagram illustrating a power grid reliability evaluation system capable of performing a method of evaluating power grid reliability based on a frequency fluctuation model according to the flowchart of FIG. 1.
4 is a flowchart showing another embodiment of a method for evaluating power grid reliability based on a frequency fluctuation model according to the idea of the present invention.
5 to 7 are flowcharts in which a method for evaluating power grid reliability based on a frequency fluctuation model according to the idea of the present invention is applied to a mid- to long-term power plan, a mid- to long-term facility plan, and a short-term operation plan.

In describing the present invention, terms such as first and second may be used to describe various elements, but the elements may not be limited by terms. The terms are only for the purpose of distinguishing one component from another component. For example, without departing from the scope of the present invention, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

When a component is connected to or is referred to as being connected to another component, it can be understood that it is directly connected to or may be connected to the other component, but other components may exist in the middle. .

The terms used in the present specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions may include plural expressions unless the context clearly indicates otherwise.

In the present specification, terms such as include or include are intended to designate the presence of features, numbers, steps, actions, components, parts, or a combination thereof described in the specification, and one or more other features or numbers, It may be understood that the possibility of the presence or addition of steps, actions, components, parts, or combinations thereof, is not preliminarily excluded.

In addition, shapes and sizes of elements in the drawings may be exaggerated for clearer explanation.

1 is a flowchart illustrating an embodiment of a method for evaluating power grid reliability based on a frequency fluctuation model according to the idea of the present invention.

The illustrated method for evaluating power grid reliability based on a frequency variation model includes the steps of constructing a power grid model (S20); Configuring a scenario for power operation for a predetermined period (S30); Estimating a frequency change of power in the scenario (S40); It may include a step (S60) of performing reliability evaluation based on the frequency change and determining that the evaluation result is reliable if the evaluation result exceeds a reference value. In addition, prior to the step S10, the step (S10) of obtaining power grid information for configuring a power grid model may be further included.

The detailed calculation procedure of the method for evaluating the reliability of the power grid based on the illustrated frequency fluctuation model is illustrated step by step below.

In the illustrated frequency fluctuation model-based power grid reliability evaluation, when a situation to change the power grid configuration occurs during power grid operation, power grid cases are evaluated as multiple candidates to change the power grid structure. At this time, the power grid model is configured for each power grid case.

In the power grid model construction step (S20), a frequency fluctuation power grid model is constructed. First, fluctuation components for configuring it are input.

The first facility to consider is a general synchronous generator. General synchronous generators are divided into generators that maintain a constant basic power generation (generators that do not participate in frequency regulation, nuclear generators, etc.), and adjustable generators (generators that participate in frequency regulation, gas generators, etc.). Among the control systems constituting the generator, only the main controllers related to the frequency characteristics are abbreviated, and the frequency change according to the time simulation is configured to be simulated.

The second target to be considered is renewable energy resources. Among the control systems of renewable energy resources, only the main controllers related to frequency characteristics are abbreviated, and the frequency change according to the time simulation is configured to be simulated. Renewable energy is configured to predict the amount of output reflecting meteorological information, etc. for the facility capacity considered in the power supply configuration, taking into account the probabilistic variability according to the Monte Carlo simulation.

The third is the limit of reserve power (maximum power supply-load). At the time of the simulation, the power supply configuration is adjusted by reflecting the reserve power of the power grid required.

The fourth is the load model. Based on the amount of demand predicted in advance for the power plan, the probabilistic volatility according to the Monte Carlo simulation is considered and reflected.

Among the four fluctuation components, the general synchronous generator has a large number of variables reflected in the modeling configuration process, but since it always operates constantly in the power grid, it is preferable to exclude it from the variables reflected in the power grid adjustment during the feedback control.

In the power grid model construction step (S20), a power grid model is constructed based on the information received for the above-described four fluctuation components. 2 is a mathematical equivalent block diagram of the constructed power grid model.

An example of how to configure the power grid model is as follows. If the block diagram is constructed in consideration of only the elements that affect the frequency fluctuation among the elements constituting the power grid, it is as shown in FIG. 2. The simplified equivalent model shown is based on the most basic governor, prime mover, rotor and load models.

, 출력을

로 정의할 때, 루프 이득

는 하기 수학식 1과 같이 규정될 수 있다.The block diagram shown can be simplified into one equivalent transfer function by applying Mason's Rule. Input

, The output

When defined as, loop gain

May be defined as in Equation 1 below.

는 하기 수학식 2와 같이 정의될 수 있으며, Δ는 하기 수학식 3과 같이 정의될 수 있다.Meanwhile, pass gain

May be defined as in Equation 2 below, and Δ may be defined as in Equation 3 below.

가 모든

에 관계되어

이므로 간략화된 등가모델의 전체 이득은 하기 수학식 4와 같이 정의된다.Pass gain

Going all

In relation to

Therefore, the overall gain of the simplified equivalent model is defined as in Equation 4 below.

에 대하여 다시 정의하면 하기 수학식 5와 같다.Output Equation 4

If it is defined again as in Equation 5 below.

에 인가하여 소정 기간, 특히, 신재생에너지와 부하의 단기 변동성을 고려한 주파수변화를 구할 수 있는 모델을 구성할 수 있다. Through the transfer function model defined as in Equation 5, the variability of renewable energy and load

It is possible to construct a model capable of obtaining a frequency change in consideration of short-term variability of new and renewable energy and load for a predetermined period by applying to.

A simplified equivalent model can be constructed by extracting the parameters of the frequency response equivalent model defined as described above from known dynamic characteristic information of the power grid.

The variables in Equation 5 are defined as follows.

은 신재생에너지와 부하의 변동성이고,

는 주파수 변화 출력이다. T_p는 prime mover time constant로서 '등가모델로 표현된 원동기의 시정수'로 정의하고, T_g는 governor time constant로서 '등가모델로 표현된 조속기의 시정수'로 정의할 수 있다. R_eq는 계통의 속도조정률(equivalent speed droop characteristic)이며, M_eq는 등가 계통 시스템 관성(inertia)이며, D_eq는 부하 등가 댐핑(damping) 계수이다.as I mentioned before

Is the volatility of renewable energy and load,

Is the frequency change output. T _p is the prime mover time constant and can be defined as'the time constant of the prime mover expressed by the equivalent model', and T _g is the governor time constant and can be defined as the'time constant of the governor expressed by the equivalent model'. R _eq is the equivalent speed droop characteristic of the _{system, M eq} is the equivalent system inertia, and D _eq is the load equivalent damping coefficient.

After constructing a simple model capable of time simulation in the illustrated power grid model configuration step (S20), in the illustrated scenario configuration step (S30), a probability model is configured in consideration of the unique variation pattern of each resource, and a predefined number Create as many mock scenarios as possible. For example, in the case of a load model, a method of modeling with a normal distribution can be applied.

As a more specific example, the basic time domain for frequency tracking consists of 5 minutes, and a consistent probabilistic input model is used during this time. This time can be changed according to the probabilistic input model, such as demand and power interruption.

입력으로 반영하고 있다. 다른 구현에서는, 도 1에서 변동성분으로 도시한, 예비력, 부하수준, 재생에너지 수준을 모두 입력으로 반영한 시나리오들을 구성할 수 있다.In general, in the power grid to which new and renewable energy is applied, fluctuations in the amount of generation of new and renewable energy occur very frequently. The variable that is most frequently changed for each scenario is the amount of generation of new and renewable energy, and the next variable that is frequently changed is It is the amount of load (demand). In Figure 2, the variation of new and renewable energy and load

It is reflected as input. In another implementation, scenarios in which all reserves, load levels, and renewable energy levels, shown as variable components in FIG. 1, are reflected as inputs may be configured.

Depending on the implementation, in the scenario configuration step (S30), power grid events that may occur during a predetermined period may be probabilistically configured. For example, if the probability of interruption of synchronous power generation is 1/100000 and the probability of partial short circuit of the load is 1/100000, only one out of 1,000,000 scenarios can be reflected for interruption of synchronous power generation, and 10 can reflect partial short circuit of the load. have.

로 얻어질 수 있다.In the step of estimating the frequency change of the power in the above scenario (S40) (abbreviated as the scenario frequency estimation step), simulation is performed based on the generated scenario and the frequency change result is stored in the DB. Simultaneous simulation should be performed for a large number of scenarios, but since the present invention uses a simplified power grid model as an equivalent model, it is possible to reduce the limitation of simulation time even when the number of scenarios is large. The frequency variation result is according to Equation 5

Can be obtained with

In another implementation, the frequency change of the power may be estimated for more diverse scenarios configured by considering all of the reserve power, the load level, and the renewable energy level, which are shown as fluctuation components in FIG. 1.

In the illustrated step S60, as a method of performing the reliability evaluation by the frequency change, the average, variance, and standard deviation for N frequency samples are calculated based on the DB generated as a result of time simulation for a plurality of scenarios, and finally We propose to calculate the frequency-based reliability index.

For example, it proposed a frequency-based reliability index FI (F requency based reliability I ndex) which may be calculated by the following method.

Keeping the frequency at a level of 99.99% in the ±0.1 Hz section based on the normal frequency of 60 Hz can be defined as in Equation 6 below.

는 모 표준편차를 의미한다. 모 표준편차

는 하기 수학식 7과 같이 정의할 수 있다. 즉,

개의 주파수 값

이 있고 이 때 모 평균을

이라고 할 때, 모 표준편차

를 정의한 것이다.In the above equation

Means the parent standard deviation. Parent standard deviation

Can be defined as in Equation 7 below. In other words,

Frequency values

And at this time, the parent average

When is, the parent standard deviation

Is the definition of

값은 주파수가 정규분포를 따른다는 가정 하에 표준정규분포표를 통해 확인할 수 있다. 정규분포표에 따르면 해당 조건을 만족하는

값은

임을 알 수 있다. Satisfying Equation 6

The value can be checked through the standard normal distribution table under the assumption that the frequency follows a normal distribution. According to the normal distribution table,

The value is

It can be seen that it is.

이어야 하므로,

임을 알 수 있으며, 이

가 본 발명에서 제시하고 있는 주파수변동기반 신뢰도 지표로 정규주파수 60㎐를 기준으로 ±0.1㎐를 구간을 99.99% 수준으로 유지하는 신뢰도 평가의 기준이 된다. 즉, ±0.1㎐를 구간을 99.99% 수준으로 유지하는

, ±0.2㎐를 구간을 99.99% 수준으로 유지하는

로 정의할 수 있다. 위에서 제시하는 방법을 적용한 전력망의 특성에 맞추어 유지구간 또는 유지율을 변경하면 별도의

를 산정할 수 있다.therefore,

Should be,

You can see that this

Is a frequency fluctuation-based reliability index proposed in the present invention, which is a standard for reliability evaluation in which ±0.1 Hz is maintained at a level of 99.99% of the normal frequency of 60 Hz. In other words, ±0.1㎐ is maintained at the 99.99% level.

, ±0.2㎐ is maintained at the 99.99% level

It can be defined as If the maintenance section or maintenance rate is changed according to the characteristics of the power grid to which the method presented above is applied, a separate

Can be calculated.

는 다음과 같이 정의할 수 있다.In this way, the frequency-based reliability index proposed by the present invention

Can be defined as follows.

를

개의 주파수 샘플을 갖는 집단에서의 표준편차라고 할 때, 정격주파수 대비 ±0.1㎐를 범위를 99.99%수준으로 유지하는 전력망의 주파수기반 신뢰도 지수를 나타내는

와 정격주파수 대비 ±0.2㎐를 범위를 99.99%수준으로 유지하는 전력망의 주파수기반 신뢰도 지수를 나타내는

는 하기 수학식 8 및 9와 같이 정의할 수 있다.

To

When it is the standard deviation in the group with four frequency samples, it represents the frequency-based reliability index of the power grid that maintains the range of ±0.1 Hz compared to the rated frequency at 99.99%.

And the frequency-based reliability index of the power grid maintaining the range of ±0.2㎐ compared to the rated frequency at 99.99% level.

Can be defined as in Equations 8 and 9 below.

가 1보다 작으면 전력망이 요구하는 주파수 수준을 유지하여 전력망 신뢰도를 만족하며, 1보다 크면 전력망이 요구하는 주파수 수준을 유지하지 못해 전력망 신뢰도를 만족하지 못하는 것으로 판정할 수 있다. 즉, 하기 수학식 10의 조건으로 전력망 신뢰도를 판정할 수 있다. In the step of determining the evaluation result,

If is less than 1, the reliability of the power grid is maintained by maintaining the frequency level required by the power grid, and if it is greater than 1, it can be determined that the reliability of the power grid is not satisfied because the frequency level required by the power grid cannot be maintained. That is, the reliability of the power grid can be determined under the condition of Equation 10 below.

In the flowchart of FIG. 1, if the reliability evaluation result does not exceed the reference value, the power grid configuration is adjusted and the power grid configuration step returns.

를 통해 전력망의 신뢰도 만족여부를 확인하고, 신뢰도를 만족하지 못할 경우, 전력망의 구성요소, 즉 전원구성, 예비력 등을 조정하여 신재생에너지의 변동성에 대한 주파수 유지가 가능한지 여부를 반복검토하기 위해, 전력망 구성 단계로 복귀하여 전력망 구성을 조정하고 이후 단계들을 다시 수행한다. 복귀한 전력망 구성 단계에서는, 다음 후보로서 다른 전력망 케이스에 대한 전력망 모델을 구성한다.In other words, as described above

In order to check whether the reliability of the power grid is satisfied or not, and if the reliability is not satisfied, it is possible to repeatedly review whether it is possible to maintain the frequency for the variability of new and renewable energy by adjusting the components of the power grid, that is, power configuration and reserve power Return to the grid configuration step, adjust the grid configuration, and perform the subsequent steps again. In the returned power grid construction step, a power grid model for other power grid cases is constructed as the next candidate.

When the power grid configuration is adjusted by returning, depending on implementation, only those that can be changed during operation among the power grid information collected in step S10 may be adjusted and returned. For example, in the steps S10 and S20, the power generation part of the general synchronous generator, the renewable energy resource, the reserve power limit, and the load are considered as variable components, but when the step is returned after the step S60, it is substantially changed to supply stable power to the system. Excluding this difficult general synchronous generator power generation part, it can only be adjusted for renewable energy resources, reserve power limit, and load.

FIG. 3 is a block diagram illustrating a power grid reliability evaluation system capable of performing a method of evaluating power grid reliability based on a frequency fluctuation model according to the flowchart of FIG. 1.

The illustrated reliability evaluation system includes: an input unit 110 for obtaining power grid information for configuring a power grid model; A modeling unit 120 that generates a power grid model capable of reflecting frequency fluctuation characteristics using the power grid information; A scenario construction unit 130 for creating two or more scenarios that can apply at least one of a new renewable energy generation amount and a power grid load to the generated power grid model; A scenario execution unit 140 for performing each of the created scenarios and collecting the results; A result processing unit 150 for performing statistical processing on the collected results; A determination unit 160 for determining the reliability of the power grid based on the statistical processing result; A display unit 180 for displaying the determined power grid reliability; When the determined power grid reliability is insufficient, a power grid adjustment unit 170 for changing a part of the power grid information may be included.

The power grid reliability evaluation system is based on a frequency fluctuation model, and functions of each component are as follows.

The input unit 110 receives resources such as synchronous generators, new and renewable energy, and reserves that reflect variability and transmits them to the modeling unit 120 in charge of configuring a power grid.

The modeling unit 120 constructs a simplified power grid equivalent model capable of time simulation by reflecting frequency fluctuation characteristics using the information obtained from the input unit 110.

The input unit 110 and the modeling unit 120 perform the step (S20) of configuring the power grid model shown in FIG. 1.

The scenario configuration unit 130 reflects the probability-based variability based on the power grid equivalent model configured by the modeling unit 120 to reflect the variability of new and renewable energy, power grid demand, etc., and simulates as many scenarios as a predefined number. Organize cases. That is, the scenario configuration unit 130 performs the scenario configuration step S30 shown in FIG. 1.

The scenario execution unit 140 performs a time simulation to simulate a frequency change using each simulation case configured in the scenario construction unit 130, records the time change result of the frequency, and records multiple scenario simulation cases. The results performed on these are converted into a DB in the storage unit 145. That is, the scenario execution unit performs the frequency estimation step (S40) shown in FIG.

,

값을 활용하여

를 연산한다.The result processing unit 150 calculates the average and variance of frequencies from the DB of the frequency variation result calculated by the scenario execution unit 140, and

,

Using the value

Computes

를 이용하여,

가 1보다 작을 경우 신뢰도 만족, 1보다 클 경우 신뢰도 미흡으로 판정한다.The determination unit 160 is calculated by the result processing unit 150

Using,

If is less than 1, the reliability is satisfied, and if it is greater than 1, the reliability is judged as insufficient.

The result processing unit 150 and the determination unit 160 perform a reliability evaluation of FIG. 1 and determine that the evaluation result is reliable when the evaluation result exceeds a reference value (S60).

The power grid adjustment unit 170 changes the elements constituting the power grid when the reliability is not satisfied according to whether or not the reliability determined by the determination unit is satisfied, and repeats the series of processes described above from the input unit to the determination unit.

The power grid adjustment unit 170 re-performs the step of constructing the power grid model with the feedback loop of FIG. 1 and the changed value accordingly (re-performation of step S10).

지수와 신뢰도 판정결과를 표시하고 저장한다. 구현에 따라 상기 판정결과도 저장부(146)에 저장할 수 있다.The display unit 180 includes input and main user-defined values of the input unit 110, the modeling unit 120, the scenario configuration unit 130, the scenario execution unit 140, the result processing unit 150, and the determination unit 160 Value and final

The index and reliability judgment results are displayed and saved. Depending on the implementation, the determination result may also be stored in the storage unit 146.

4 is a flowchart illustrating another embodiment of a method for evaluating power grid reliability based on a frequency fluctuation model according to the idea of the present invention.

It can be seen that in the step of obtaining power grid information for configuring the power grid model in the illustrated flowchart (S110), it is almost the same as the flowchart of FIG. 1 except that information on ESS and demand resources and other flexible resources are input. I can.

The power grid reliability evaluation method in the illustrated flow chart provides a frequency-based reliability index reflecting the volatility of the power grid, so that it can be used to review the effects of ESS and demand resources linked to the power grid to maintain frequency or provide reserve power. That is, in FIG. 1, only reserve power, load model, and renewable energy are reflected as variable components, whereas in FIG. 4, other flexible resources such as ESS and demand resources are reflected as elements that can configure the power grid as variable components.

가 변하게 되고, 그 결과에 의해 해당 유연자원의 유효성을 확인하여 전력망 계획자가 전력망 계획시 유용하게 활용할 수 있다.If you configure a simple power grid by configuring it as shown,

Is changed, and the power grid planner can use it usefully when planning the power grid by checking the validity of the flexible resource according to the result.

By changing the time domains of the devices and systems proposed in the present invention, it is possible to determine the appropriateness of the power configuration, power facilities, and reserve levels in the planning and operation of the long-term, mid-term, and short-term power grids. It can be effectively used in establishing a short-term power grid operation plan in the power grid including.

5 to 7 are flowcharts in which a method for evaluating power grid reliability based on a frequency fluctuation model according to the idea of the present invention is applied to a mid- to long-term power plan (Fig. 5), a mid- to long-term facility plan (Fig. 6), and a short-term operation plan.

The mid- to long-term power plan, mid- to long-term facility plan, and short-term operation plan may have FI reference values different from those of FIG. 1.

In the case of the mid- to long-term power plan shown in FIG. 5, it is possible to find out the effect of the power grid caused by a new generator to be installed in a relatively distant future or an old generator to be abolished. That is, in order to satisfy the standard FI as a result of evaluating the reliability of the power grid model for the mid- to long-term power plan, it is possible to adjust the configuration of the prime mover/renewable power source or additionally secure reserve resources.

On the other hand, when a mid- to long-term power plan is determined, a mid- to long-term power facility plan is derived as a new or abolished plan for the transmission network, substation, and special facilities for operating the determined generator configuration. As shown in Fig. 6, even in the case of a mid- to long-term facility plan, in order to satisfy the standard FI as a result of the reliability evaluation of the power grid model for the mid- to long-term facility plan, the transmission/substation facility plan is adjusted or FACTS (Flexible Alternating Current Transmission Systems: Flexible transmission system) and other flexible resources can be additionally secured.

In the case of the short-term power grid operation plan in FIG. 7, in order to satisfy the standard FI as a result of power grid reliability evaluation, the prime mover power start-up and stop plan is adjusted, the output of renewable energy generation is adjusted, or quick-response reserve resources (such as pumped-up power generation) are used. You can secure more.

Those skilled in the art to which the present invention pertains, since the present invention can be implemented in other specific forms without changing the technical spirit or essential features thereof, the embodiments described above are illustrative in all respects and should be understood as non-limiting. Only do it. The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. .

110: input unit
120: modeling unit
130: Scenario configuration unit
140: scenario execution unit
150: result processing unit
160: judgment unit
170: power grid control unit
180: display

Claims (14)

Constructing a power grid model;
Configuring a scenario for power operation for a predetermined period;
Estimating a frequency change of power in the scenario; And
Performing reliability evaluation by the frequency change and determining that the evaluation result is reliable if the evaluation result exceeds the reference value
Power grid reliability evaluation method comprising a.
The method of claim 1,
If the reliability evaluation result does not exceed the reference value, the power grid configuration is adjusted, and the power grid reliability evaluation method returns to the power grid model configuration step.
The method of claim 2,
Further comprising the step of obtaining power grid information for configuring a power grid model,
If the reliability evaluation result does not exceed the reference value, the power grid reliability evaluation method of adjusting and returning only those that can be changed during operation among the power grid information.
The method of claim 1,
In the power grid configuration step,
Power grid reliability evaluation method that considers the power generation part of general synchronous generator, renewable energy resources, reserve power limitation, and load as variable components.
The method of claim 4,
In the power generation part of a general synchronous generator, a power grid reliability evaluation method that considers the prime mover element and the governor element.
The method of claim 4,
The scenario configuration step and the frequency change estimation step are performed for a plurality of scenarios,
In each of the above scenarios, the power grid reliability evaluation method, characterized in that the variation for the new and renewable energy and the load are set differently.
The method of claim 4,
In the frequency change estimation step, the power grid reliability evaluation method for checking the frequency change according to the following equation.

(

: Renewable energy and load volatility,
T _p : Time constant of the prime mover expressed by the equivalent model,
T _g : Time constant of the governor expressed by the equivalent model,
R _eq : system speed adjustment rate,

: Frequency change output
M _eq : equivalent system system inertia, D _eq : load equivalent damping factor)
The method of claim 4,
In the step of determining that it is reliable,
A power grid reliability evaluation method in which the frequency change is determined according to a frequency-based reliability index of a power grid maintaining a predetermined'probability level approximating 1'in a range of an allowable width compared to a rated frequency.
The method of claim 8,
In the step of determining that it is reliable,
The power grid reliability evaluation method is defined according to the following equation, and the frequency change is determined according to the frequency-based reliability index of the power grid maintaining a range of ±0.1 Hz or ±0.2 Hz compared to the rated frequency at a level of 99.99%.

(N: number of frequency samples,

:

Standard deviation in a population of 4 frequency samples,
FI: frequency-based reliability index)
An input unit for obtaining power grid information for configuring a power grid model;
A modeling unit that generates a power grid model capable of reflecting frequency fluctuation characteristics using the power grid information;
A scenario construction unit for creating two or more scenarios that can apply at least one of a new renewable energy generation amount and a power grid load to the generated power grid model;
A scenario execution unit that executes each of the created scenarios and collects the results;
A result processing unit that performs statistical processing on the collected results;
A determination unit that determines the reliability of the power grid from the statistical processing result;
A display unit for displaying the determined power grid reliability; And
When the determined power grid reliability is insufficient, a power grid adjustment unit that changes a part of the power grid information
Power grid reliability evaluation system comprising a.
The method of claim 10,
The modeling unit,
Power grid reliability evaluation system that generates a model by considering the power generation part of general synchronous generator, renewable energy resource, reserve power limit, and load as variable components.
The method of claim 11,
The scenario configuration unit,
Create a number of scenarios in which the fluctuations for renewable energy and load are set differently,
The scenario execution unit,
A power grid reliability evaluation system for estimating a frequency change due to a change in the renewable energy and load.
The method of claim 10,
The scenario execution unit, the power grid reliability evaluation system to check the frequency change according to the following equation.

(

: Renewable energy and load volatility,
T _p : Time constant of the prime mover expressed by the equivalent model,
T _g : Time constant of the governor expressed by the equivalent model,
R _eq : system speed adjustment rate,

: Frequency change output
M _eq : equivalent system system inertia, D _eq : load equivalent damping factor)
The method of claim 10,
The determination unit,
The power grid reliability evaluation system for determining the frequency change according to the frequency-based reliability index of the power grid maintaining a predetermined'probability level approximating 1'in the range of the allowable width compared to the rated frequency.

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