WO2014101515A1

WO2014101515A1 - Method for designing automatic generation control model under grid connection of intermittent energy

Info

Publication number: WO2014101515A1
Application number: PCT/CN2013/084688
Authority: WO
Inventors: 丁剑; 邢田伟; 申洪; 宋新立; 郑超; 宋云亭; 张琳; 姜宁; 魏磊
Original assignee: 国家电网公司; 中国电力科学研究院; 西北电网有限公司
Priority date: 2012-12-24
Filing date: 2013-09-30
Publication date: 2014-07-03
Also published as: CN103066620B; CN103066620A

Abstract

The present invention relates to the field of grid-connected operation of renewable energy power generation, and particularly relates to a method for designing an automatic power generation control model in an intermittent energy grid connection, comprising the steps of: A. constructing a time-amplitude two-dimensional disturbance source of a grid-connected intermittent energy disturbance; B. analysing the power grid power fluctuation characteristics; C. determining a distribution scheme of automatic generation control (AGC) system sets; D. determining the standby size of a power supply of an AGC system and the type of power supply; E. making a control policy for the AGC system; F. selecting a frequency bias factor; and G. determining a parameter design scheme of the AGC model. The present invention relates to the influences of large-scale wind power and solar photovoltaic power supply on secondary frequency modulation of a power grid, and can construct an AGC model and parameters on the basis of same, thereby effectively coping with the power disturbance of the intermittent wind power and photovoltaic power supply, improving the secondary frequency modulation effect of the power grid under the fluctuation of the intermittent energy power supplies and improving the ability of the power grid to accept renewable energy resources.

Description

Technical field

The invention relates to the field of grid-connected operation of renewable energy power generation, and particularly relates to a design method of an automatic power generation control model under the intermittent energy grid. Background technique

In recent years, with the introduction of policies to encourage the development and utilization of clean energy, wind power and solar photovoltaic power generation have developed rapidly. Take the Northwest Power Grid as an example. At present, the installed capacity of wind power in the northwest region is the highest in Gansu. By the end of 2011, there were 44 wind farms in Gansu, with a power generation of 7.133 billion kWh, a year-on-year increase of 248.13%. Among them: 40 wind farms in Jiuquan area, generating 3.9 billion kWh; 3 wind farms in Baiyin, generating 230 million kWh. The largest power generation output of wind power (April 22) was 2.66 million kilowatts, accounting for 21% of the total power generation output of the whole network at that time, accounting for 27% of the total electricity load of the whole network, accounting for 32% of the lowest power load of the whole network on that day. The maximum daily power generation of wind power (April 10) was 55.19 million kWh, accounting for _{i 8.} 4% of the total power generation of the day, accounting for 25% of the total electricity consumption of the day. In some periods, wind power generation exceeds hydropower and becomes the second largest power source for the system.

Too |3⁄4 can be an inexhaustible source of natural energy. With abundant solar energy resources and no pollution to the environment, it is one of the ideal energy sources to meet the needs of sustainable development. Ffl solar energy resources, reducing dependence on fossil energy and achieving the goal of replacing some fossil fuels, will play an increasingly important role in economic development, environmental improvement and meeting people's electricity needs. The northwest power grid is rich in solar energy resources and has a vast flat desert and Gobi. Among them, Qinghai Province's solar energy resources are more prominent. According to estimates, the province's solar radiation is 160 to 175 kcal I square centimeter. In the Qaidam area of Qinghai, the annual sunshine hours are 3,553 hours. It is a famous "sunshine zone" with a high development value. The unutilized land area in Haixi is 200,000 square kilometers, and the potential for developing photovoltaic power generation projects is huge.

Large-capacity access to renewable clean energy is an inevitable trend. Renewable energy sources such as wind energy and solar energy have environmental advantages, but there are also shortcomings such as power generation output being greatly affected by meteorological conditions and difficult to make long-term prediction and dispatch control. After large-capacity wind power and photovoltaic power are connected to the system, it may cause a large active disturbance to the system. In the same power system, the load forecast has an error of about 2%-5%: The large load may suddenly fluctuate, and the unit may suddenly stop due to the failure. These factors mean that the power generation and load of the power system may vary from day to day. The power is not balanced. Severe power imbalances can affect system frequency, voltage, and even fragile receiver grids can cause voltage instability due to severe power imbalance.

The above-mentioned high-power shortage disturbances have experienced a long time in large-scale power systems, and the range of voltage and frequency changes. Larger, involving more power system components, the general electromechanical transient simulation program is difficult to carry out accurate simulation. Therefore, the study of the above problems requires the application of full process simulation technology. The whole process dynamic simulation focuses on simulating the whole process of the power system. The time domain is wide and the phenomenon description is realistic. 3⁄4 to simulate the actual dynamic process of the power system more realistically, the simulation and research work of the power system can be deepened and the operation personnel can be easily assisted. Develop reasonable measures and defensive strategies to avoid potential grid accidents caused by power imbalances in the medium and long term process. This is important to avoid large-scale blackouts and to study effective measures to prevent accidents from expanding (the third line of defense).

The automatic power generation control model and parameter setting method under the intermittent energy grid are the grids of renewable energy power generation and grid operation. However, the rapid development of new energy sources and grid-connected networks have also brought enormous challenges to the power grid. On the one hand, the power grid cannot meet the problems of large-scale wind power and photovoltaic power generation access and delivery. On the other hand, wind power and solar photovoltaic power sources are qualitative in nature. It is an intermittent energy source with randomness, volatility and poor adjustability. It often requires a large number of other power supplies with regulation to suppress its volatility, increasing the frequency modulation and peak shaving of the power grid, and increasing the grid rotation. Spare capacity. However, due to the nature of its intermittent energy, wind power and photovoltaic provide the motive power for generating electricity that is uncontrollable and cannot be stored. It cannot be increased or decreased at will. The concept of traditional power generation, automatic power generation control (AGC) cannot be applied to wind power and photovoltaic power. Control must break through the existing active control ideas and study the simulation analysis method of automatic power generation control (AGC) design that can measure the characteristics of intermittent energy. Summary of the invention

In view of the deficiencies of the prior art, the present invention provides a method for designing an automatic power generation control model for intermittent energy grid-connected, and the method provided by the invention ensures the secondary frequency modulation effect of the system under various power disturbances of the intermittent energy source, and improves The grid's ability to accept intermittent 3⁄4 renewable energy sources achieves the goal of fully benefiting clean energy such as wind energy and solar photovoltaic power.

The object of the present invention is achieved by the following technical solutions:

A method for designing an automatic power generation control model for intermittent energy grid-connected, which is improved in that the method includes the following steps -

Α Build a time-amplitude two-dimensional disturbance source for grid-connected intermittent energy disturbances;

Β Analysis of grid power fluctuation characteristics;

C. Determine the distribution scheme of the automatic power generation control AGC system unit;

D, determine the automatic power generation control AGC system power supply ffl size and power type;

E. Formulate automatic power generation control AGC system control strategy;

F, selecting a frequency deviation coefficient;

G. Determine the parameter design scheme of the automatic power generation control model. Wherein, in the step A, constructing the time-amplitude two-dimensional perturbation source of the grid-connected intermittent energy disturbance comprises the following steps: a, constructing a function of the secondary frequency modulation effect and its influencing factors;

b. Determine whether there is wind power in the intermittent energy source connected to the grid;

c. Determine whether there is photovoltaic power in the grid-connected intermittent energy source;

d. Determine whether there is wind power and photovoltaic power in the grid-connected intermittent energy source;

e. forming a source sample space of a two-dimensional disturbance domain of the intermittent energy source;

f, taking a value from a diagonal sample in the source sample space;

g. Obtain intermittent energy source time-amplitude two-dimensional disturbance source.

Wherein, in the step a, the function of the secondary frequency modulation effect and its influencing factors is represented by the following formula -

./FM effect Κί,ν), ί„] = . 2D disturbance domain, unit distribution, control model, parameter setting) _φ

[(time factor, amplitude factor), unit distribution, control model, parameter setting]

Its Φ: t represents the time factor in the two-dimensional disturbance domain; V represents the amplitude factor in the two-dimensional disturbance domain; d represents the influence of the automatic power generation control AGC unit distribution; m represents the influence of the control model; c represents the influence of the parameter setting .

Wherein, in the step b, if there is a wind power source, collect the wind power source time-amplitude (t„, _VK ) sample and perform the step ^ otherwise, proceed to step 0.

Wherein, in the step c, if there is a photovoltaic power source, collect the time-amplitude (t„, _V ) sample of the photovoltaic power source and perform the step mountain or proceed to step d.

Wherein, in the step d, if there is wind power and photovoltaic power source at the same time, the wind power and photovoltaic power source ( , ) sample superposition effect analysis is performed and step e is performed _; otherwise, step e is performed.

Wherein, in step e, the source sample space of the two-dimensional perturbation domain of the inter-source power source is represented by the following formula -

Where: (t _n , v _n : is a set of samples, indicating that under the time span of t _n , the statistical maximum wind power fluctuation amplitude is n=], 2, 3 ' where

Wherein, in the step g, the formula 3 is the obtained intermittent energy source time-amplitude two-dimensional disturbance source. Wherein, in the step B, the power fluctuation characteristic of the power grid is analyzed based on the analysis of the exchange power deviation evaluation criterion; (t _n , v _{n is} used as the disturbance amount in the two-dimensional disturbance domain, and the automatic power generation is not analyzed under the disturbance amount. Control the AGC system il-inch grid power fluctuation characteristics.

Among them, the analysis of grid power characteristics includes the following steps -

(1) The amount of change in the power of the section ir section, that is, the following changes;

Wherein: - represents the disturbance zone, the power variation section of the disturbance zone; Δ / ^ unscrambled _Μ _move; unperturbed power change represents a sectional area of the i, i = l, 2 ...! ! ;

(2) Determine whether the exchange power deviation between the disturbance zone and the non-disturbance zone is different, that is:

^Δ 3⁄4 moving zone ' ^Δ 3⁄4 disturbance zone i ^{< 0} ® ^;

If there is a difference sign of the exchange power difference between the disturbance zone and the non-disturbance zone, perform the determination scheme of the automatic power generation control AGC system unit in step C;

Otherwise, the exchange power deviation between the disturbance zone and the non-disturbance zone appears as the same symbol, namely:

- > 0 ( :) Record the area and query the tie line that causes the exchange power deviation between the disturbance zone and the non-disturb zone to reduce the number of the tie line.

Wherein, in the step C, the automatic power generation control AGC system unit distribution plan aims to reduce the cross-section tie line power deviation and the frequency deviation in the secondary frequency modulation stage, that is:

I ^ → secondary frequency end ^υ

[t— Once Gong Gong 0, in the step D, “ ^{Vn is} used as the disturbance amount in the two-dimensional disturbance domain, and the total spare capacity of the power system is expressed by the formula; Where: indicates the secondary spare capacity of the control area; /„ is the maximum fluctuation of the load at the same time scale as the wind power; the alternative capacity scheme is used to recover the power of the cross-section power exchange, the frequency recovery and the regional deviation control ACE signal (ACE is The regional deviation control, which represents the power deviation of the area in a specific control mode, the AGC M group adjusts the output according to this signal, and finally makes fff as follows: 9 ·

Where: ΔΡ, Δ and ACE are the discriminant indicators of the effect of the secondary frequency modulation in the secondary frequency modulation time; ί take the minute level unit calculation;

According to the automatic power generation control AGC system unit adjustable capacity and adjustment speed to determine the power type of the FM factory. Wherein, in the step Ε, the unit output of the automatic power generation control AGC system control area satisfies the following formula -

ACE Af < 0 10: where, the regional deviation control signal indicating the control region: 4 "represents the power system frequency deviation; the three indicators of the ACE signal return to zero by the tie line exchange power recovery, frequency recovery and regional deviation control are evaluated, ie ΔΡ, 4 / and _ACE , with the speed of the three indicators zero, the magnitude of the deviation, and the unit output coordination between the control areas as the evaluation criteria, the control strategy of the automatic power generation control AGC system is obtained.

Wherein, in the step F, the maximum fluctuation amount (t _n , v^ and large-scale wind power off-network (t _s , v _m ^) of the wind power base is used as the disturbance source to: ^2% The annual maximum peak load is the value range (the annual maximum load refers to the maximum load occurring during the year, here refers to the annual maximum load value of 1~2%), and the control area is compared with the case of 4a^f > 0. The regional frequency deviation setting selects the optimal frequency deviation coefficient of the control region.

In the step G, the parameter design includes a natural frequency deviation coefficient setting ir.

Compared with the prior art, the beneficial effects achieved by the present invention are -

1. The design method of the automatic power generation control model under the grid-connected intermittent energy source provided by the present invention clearly proposes the objectives, specific steps, frameworks and schemes of the automatic power generation control model and parameter design under the intermittent energy grid-connected network, and proposes The construction process of the two-dimensional perturbation source of the inter-time T-wave amplitude of the intermittent energy disturbance, the automatic power generation control model and the general design of the parameter design, and the complete automatic power generation control model and parameter design method under the grid of intermittent energy are formed for the future. System models and parameter selection provide ideas and design methods. 2. The design method of the automatic power generation control model under the intermittent energy grid provided by the present invention comprehensively and objectively accounts for the influence of large-scale wind power and solar photovoltaic power sources on the secondary frequency modulation of the power grid, and can be constructed on this basis. Automatic power generation control model and parameters. The automatic power generation control system model and parameters designed based on this method can effectively cope with the power disturbance of intermittent wind power and photovoltaic power supply, and greatly improve the effect of system secondary frequency modulation. This ensures intermittent new energy power supply. The normal operation of the system after large-scale access is of great significance, and is also conducive to expanding the system's access to intermittent wind power and solar photovoltaic power.

3. The design method of the automatic power generation control model under the intermittent energy grid provided by the invention effectively improves the secondary frequency modulation effect of the grid under the intermittent performance source power fluctuation, and improves the grid's ability to accept renewable energy. DRAWINGS

1 is a flow chart of constructing a time-amplitude two-dimensional perturbation source considering the grid-connected intermittent energy disturbance provided by the present invention; FIG. 2 is a schematic diagram of a typical interconnected system provided by the present invention;

3 is a flow chart of a method for designing an automatic power generation control model for intermittent energy integration in the present invention. detailed description

The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

The invention provides a method for setting the automatic power generation control model under the intermittent energy grid, and proposes a time-amplitude two-dimensional disturbance source construction idea and process considering the grid-connected intermittent energy disturbance in the simulation research of automatic power generation control: The exchange power deviation criterion for evaluating the power fluctuation characteristics of the grid and the distribution and positioning principle of the automatic power generation control AGC unit, the automatic power generation control AGC backup power supply size and the power source type determination criterion; The automatic power generation control AGC system control strategy formulation principle and the frequency deviation coefficient selection are established. Based on this principle, the automatic power generation control model and parameter design simulation analysis process under the intermittent energy grid are established, and a complete design method of automatic power generation control model under intermittent energy integration is formed.

The flow of the design method of the automatic power generation control model under the intermittent energy grid connection provided by the present invention is shown in FIG. 3, and includes the following steps -

A. The time-amplitude two-dimensional disturbance source of the grid-connected intermittent energy disturbance is considered in the simulation of automatic power generation control simulation. The specific process is shown in Figure 1, including the following steps: a. Constructing the secondary frequency modulation effect and its influencing factors The function;

After the large-scale intermittent energy is concentrated and connected to the grid, it is regarded as a two-dimensional disturbance domain composed of the time axis and the fluctuation amplitude axis for the power grid, and the fluctuation amplitude will also increase with the increase of the day T interval of the study. Increase. Considering the influence of this two-dimensional disturbance domain on the design of the AGC system, it is necessary to influence the span of the ^, the amplitude of the fluctuation, the steepness of the fluctuation, the direction of the change of the output, etc. In the disturbance domain, different values and values will affect the method. To the overall frequency modulation effect of the system, therefore, the AGC system with the needle It is necessary to adapt to all sample values in the entire two-dimensional disturbance domain. In the present invention, a function of the secondary frequency modulation effect and its decisive influence factors is constructed:

^^[( vK ^/ (two-dimensional disturbance domain, unit distribution, control model, parameter setting)

Where: t represents the time factor in the two-dimensional disturbance domain; _V represents the amplitude factor in the two-dimensional disturbance domain; d represents the influence of the AGC unit distribution; m represents the influence of the control model; c represents the influence of the parameter setting. The control effect of the overall automatic power generation control AGC system is determined by four factors in the formula.

b. Determine whether there is wind power in the grid-connected intermittent energy source; if there is wind power, collect wind power-amplitude

( t

Take the sample and proceed to step c; otherwise, proceed to step (;.

c. Determine whether there is photovoltaic power supply in the grid-connected intermittent energy source; if there is photovoltaic power supply, collect the photovoltaic power supply time-amplitude (t _n , _v sample and carry out the step mountain or proceed to step d. d, judge the grid-connected intermittent energy source Whether there is wind power and photovoltaic power supply at the same time; if there is wind power and photovoltaic power supply at the same time, carry out wind power and photovoltaic power supply ( , ^ν ^ sample superposition effect analysis and carry out the steps otherwise proceed to step e.

e. Forming the source sample space of the two-dimensional disturbance domain of the intermittent energy source - specific to wind power and photovoltaic power sources, due to the small scale of the single machine, the impact time-amplitude characteristics of the overall wind power base and the photovoltaic base are very significant, in comparison The distribution of wind power and solar photovoltaic power sources, control models and parameters have little effect, in actual engineering imitation. The apparent two-dimensional perturbation domain is represented by the following formula:

Where (t _n , v is a set of samples, expressed in t _i; time span, statistical maximum wind power

Ϊ́ΐ = ^: 1, 2, 3 · - . f, taking a value from a diagonal sample in the source sample space;

In the sample space shown in Equation 2; the probability of the sample above the diagonal is small in the actual system, and the value below the diagonal cannot reflect the maximum impact of the wind on the system under a specific span. Therefore, the actual engineering Φ can consider taking the sample of the value on the diagonal of the two-dimensional disturbance domain, namely:

(t, V) engineering value = |

( ( ^ j (3): In the construction process of the actual grid AGC system, the maximum fluctuation of the wind power in the secondary frequency modulation time I is required as the disturbance value. Under this disturbance, the optimal control mode and parameter setting are studied, and the AGC system control effect is corrected. During the test, all fluctuations need to be considered. In the construction process, samples (t _n , v _n ) in the two-dimensional disturbance domain are taken. All values of (t, v) _xig3⁄4tt should be considered in the verification process. . For wind power only or solar photovoltaic power only, consider separately. For systems with two intermittent energy sources connected at the same time, the superposition effect of the two needs to be considered.

g. Obtain intermittent energy source time-amplitude two-dimensional disturbance source; Equation 3 is the obtained intermittent energy source time-amplitude two-dimensional disturbance source.

B, analysis of grid power fluctuation characteristics under disturbance based on exchange power deviation evaluation criteria, including the following steps;

(1) Statistical change in section section power:

In the absence of automatic power generation control AGC system, after the power disturbance occurs in the power system, the power transmission between the various regions will inevitably change due to the effect of primary frequency modulation, and the power of the section between the various regions in the power grid can be analyzed. The overall trend of change. According to the classic two-zone system, as shown in Figure 2, where power is transmitted from system A to system B. In the absence of system A, the input power of system B is reduced. The power deviation of the section in the ACE signal of system B is calculated as follows Type:

:::: After the initial β motion Β <0; When the frequency deviation coefficient of the system 选择 is selected properly, the system Β regional control deviation ACE ) does not participate in the frequency adjustment. In the actual power grid, due to the complexity of the power grid, the change of the section power of each area after the disturbance is not necessarily the case of the above typical system. For the analysis of the grid without the AGC system, it is necessary to use the two-dimensional disturbance domain of the wind power base. (t _E , v _n ) is the disturbance amount. Analyze the variation of the section power under this disturbance under each disturbance. Calculate whether the trend of the section power change is related to the type system, that is, the following changes:

"AR - disturbance zone

1≡ disturbance zone 1

△ non-disturbed zone

Where: ^ disturbance _{+ |:} zone ₇ table ' shows the section power variation of the disturbance zone; A3⁄4 _j represents the section power variation of the non-disturbance zone i, ϊ = 2 · · · η;

(2) Determine whether the exchange power deviation between the disturbance zone and the non-disturbance zone is different, that is, the non-disturbance zone ΐ 5- Under normal circumstances, the symbol of the disturbance zone should be opposite to the sign of the non-disturbance zone.

> 0 < 0

AP, non-disturbed area 1 < 0 > ()

< 0 > 0 If the disturbance zone power deviation difference symbol appears, proceed to step C to determine the distribution scheme of the automatic power generation control AGC system unit;

Δ3⁄4 moving zone ' ^ disturbance zone i > 0

Then, the area is recorded, and the contact line causing the exchange power deviation between the disturbance zone and the non-disturbance zone is inquired, and the unit of the tie line is reduced.

At this time, the undisturbed zone i and the disturbance zone exchange power deviation are the same, which is caused by the interaction of the disturbance zone, the non-disturbance zone i, the sub-disturbance zone ^ i and the non-disturbance zone, and the specific disturbance is required. After the occurrence of the power changes of each line on these sections, find the main tie line that causes this phenomenon, and make an analysis basis for the next step to arrange the unit distribution.

C. Determine the automatic power generation control AGC unit distribution scheme - When the power disturbance occurs in the system, the AGC unit adjusts the current output according to the ACE signal. The symbol direction of the regional control deviation ACE signal indicates the output direction of the AGC unit, and its size represents the overall power of the system. The shortage; the change of the output of the AGC unit will change the current frequency of the system and the exchange power of the section, and finally the regional control deviation ACE signal will be zeroed, so the output of the AGC unit interacts with the ACE signal. During the calculation and verification process, it is still necessary to use the wind power two-dimensional disturbance domain (for the disturbance amount).

The distribution of the unit should not be excessively concentrated in the power grid, and it is necessary to first consider the hydropower unit with good frequency modulation performance, and then select the Chinese medium voltage thermal power unit. According to the analysis of the previous step, when

It is necessary to pay attention to the distribution problem of the unit in the vicinity of the non-disturbed area i and other adjacent areas. If the distribution is unreasonable, the power deviation signal of the section in the ACE signal will be affected by the output of the AGC vanadium group, and the deviation may increase, eventually resulting in the frequency being unrecoverable. In the initial state, ie:

1 Af inch 0

A ⁱ i→the end of the second frequency modulation ^ ^ν ,

Where: t can be calculated in minutes. In the process of adjustment, the section power in the vicinity of the non-disturbing zone ^ is biased Gradually expanding, and the frequency deviation does not return to the initial situation at the end of the secondary frequency modulation. It can be considered that the secondary frequency modulation caused by the primary frequency modulation characteristics of the power grid and the unit distribution cannot be completed. At this time, it is necessary to exclude the units near the main tie line found in step 2, so that the output of the AGC unit does not affect the correctness of the ACE signal. The final goal of the unit distribution is that even if the cross-section tie line power deviation and frequency deviation are zeroed in the secondary frequency modulation stage, namely:

I ^→End of secondary frequency modulation 0 Under this strategy, it is possible to determine the distribution area of the secondary frequency modulation unit for each partition. In this area, the AGC unit can be selected to avoid the influence of the power grid characteristics and the frequency modulation of each area. The problems brought about are the basic work for selecting the type of unit and determining the secondary frequency modulation standby.

D. Determine the automatic power generation control AGC backup power supply size and power supply type;

After wind power is connected to the grid on a large scale, the power needs to be absorbed in a wider range. The power fluctuations also need to be jointly absorbed by multiple regions. Therefore, each region must have a certain secondary frequency modulation capacity, and during the verification process ( t _n , v _n :) is the amount of disturbance, and the total spare capacity of the system can be expressed by the following formula -

_Wherein:;? Represents a control area f of the secondary spare capacity; / "is the maximum amount of fluctuation of the wind load the same time scale: the spare capacity determining section programs to restore power to the power exchange, recovery and ACE-zero signal frequency The situation is based on the following formula:

In the formula: ! P ·, Δ ' and ACE are the distinguishing indicators of the advantages and disadvantages of the secondary frequency modulation, which is expressed as the ffl which can be used for the error adjustment under the given secondary standby time in the secondary frequency modulation time.

The upper and lower limits of the output change of the hydropower unit are 20~150% of the rated installed capacity per minute. The upper and lower limits of the output speed of the thermal power unit are 1~5% of the rated installed capacity per minute, from the adjustable capacity and the adjustment speed. Two basic requirements for frequency modulation 出发, the hydropower plant in the system should generally choose hydropower for the frequency modulation plant, no hydropower plant or hydropower plant should not undertake the frequency modulation task ^, for example, the flood season selects the medium temperature and pressure electric power for the frequency modulation Γ .

E. Develop an automatic power generation control AGC system control strategy: The basic principle of load frequency control for interconnected power systems is that under a given tie line exchange power condition, each control area is responsible for handling the load disturbances that occur in the area. Only in case of emergency, the adjacent system is given temporary accident support and the best dynamic performance is obtained during the control process. According to this concept, the strategy of load frequency control of interconnected power systems should fully consider the following factors: First, each control area can only adopt one load frequency control strategy; Second, in the interconnected power system, there can only be at most one control area. The fixed frequency control mode is adopted; the third is that in two interconnected control systems, the fixed switching power control mode cannot be used at the same time.

When large-scale wind power is connected to the grid, AGC needs to stabilize the load and wind power fluctuations. According to the survey, the wind power minute-level fluctuation ratio is much larger than the load fluctuation ratio. When the wind power penetration rate is large, the overall power fluctuation of the system is proportional to the wind power. More than the load, and need to be shared with other areas, so in the development of the automatic power generation control AGC system considering large-scale wind power grid connection on the basis of the above factors, we should also consider the following factors: First, the need to fully call hydropower resources Rich areas, give full play to the advantages of hydropower in frequency modulation: Second, the need to relax the strict constraints on the section under the joint consumption mode - the third is to consider the automatic power generation control AGC when formulating the actual grid control strategy and dividing the control area In the case of system power fluctuation characteristics, to avoid unreasonable unit coordination between the various regions, the unit output of each control area meets the following formula -

ACE Af < Q 10: where: ' ^4C 3⁄4 indicates the regional deviation control signal of the control region; indicates the power system frequency deviation: The formula means: When the system frequency drops, each region should take the guaranteed system frequency as the primary task, so that The AGC unit increased its output. When comparing the various control strategy schemes, the frequency recovery, the tie line exchange power recovery and the ACE signal return to zero. The indicators are based on the evaluation, namely Δ \ Α and ACE, with these indicators The speed of return to zero, the magnitude of the deviation, and the output of the unit between the regions are evaluated as the evaluation criteria, and the best solution is selected.

F, select the frequency 㑩 difference coefficient:

The frequency deviation coefficient in the current AGC system is the sampling, calculation, and average income of the data during the maximum load period of the current year. In order to ensure the stability of the control, the natural frequency response of the power grid is usually required to be under the load operation level of the actual power grid in one year. The change should not be too large, and the North American Electric Reliability Association (NERC) requires that the maximum enthalpy should not be greater than twice the minimum beta value. The empirical value of Β is usually about 1 to 2% of the annual maximum peak load / 0.1 Ηζ.

After determining the AGC control model, it is necessary to determine the size of each region B coefficient. At this time, it is necessary to consider the maximum fluctuation amount of the wind power base in the range between the secondary frequency modulation days T, that is, (t _n , v _n ), and the same day T is also required. Consider extreme conditions, such as wind power Around the net, and the dish). Under these two disturbances, compare the frequency deviation settings of each region. In the case of large-scale off-grid wind power, ACE may have ' ^{4 3⁄4} ^ ^{> Q} due to excessive cross-section power deviation. At this time, it can be increased within the range of i~2% annual maximum peak load. The large B coefficient reduces the possibility of a counter-tune phenomenon in the M group.

G, determine the parameter design scheme of the automatic power generation control model; the parameter design includes the design of the natural frequency deviation coefficient. Through the above seven steps, it is possible to establish an AGC system model and parameters suitable for large-scale intermittent wind power and solar grid-connected automatic power generation control.

The invention provides a design method of an automatic power generation control model under the grid-connected intermittent energy source, which ensures the secondary frequency modulation effect of the power grid under various power disturbances of the intermittent energy source, and improves the acceptance capability of the power grid to the rest-type renewable energy source, Achieve the goal of making full use of clean energy such as wind energy and solar photovoltaic power.

It should be noted that the above embodiments are only for explaining the technical solutions of the present invention and are not limited thereto, although the present invention will be described in detail with reference to the above embodiments, and those skilled in the art should understand that the present invention can still be The invention is to be construed as being limited to the scope of the appended claims.

Claims

Rights request

A method for designing an automatic power generation control model for intermittent energy grid-connected, characterized in that the method comprises the following steps:

Α, the time of constructing grid-connected intermittent energy disturbances - amplitude two-dimensional disturbance source;

Β Analysis of grid power fluctuation characteristics;

D, determine the automatic power generation control AGC system power supply ffi size and power type;

E. Formulate automatic power generation control AGC system control strategy;

F, selecting a frequency deviation coefficient;

G. Determine the parameter design scheme of the automatic power generation control model.

2. The method for designing an automatic power generation control model for intermittent energy grid-connected according to claim 1, wherein in step A, a daily T-amplitude two-dimensional disturbance source for grid-connected intermittent energy disturbance is constructed. The following steps are included - a, a function of constructing a secondary frequency modulation effect and its influencing factors;

d. Judging whether the grid-connected intermittent energy source Φ has the same wind and photovoltaic power;

f, taking a value from a diagonal sample in the source sample space;

g, get intermittent energy supply time - amplitude two-dimensional disturbance source.

3. The method for designing an automatic power generation control model for intermittent energy grid-connected according to claim 2, wherein in the step a, the function of the secondary frequency modulation effect and its influencing factors is expressed by the following formula -

/^ _3⁄4 [( , _V ), i , ^c / (two-dimensional disturbance domain, unit distribution, control model, parameter setting),

= / [(time factor, amplitude factor), unit distribution, control model, parameter setting] ' where: t represents the time factor in the two-dimensional disturbance domain; V represents the amplitude factor in the two-dimensional disturbance domain; d represents automatic The influence of power generation control AGC unit distribution; m indicates the influence of the control model; c indicates the influence of parameter setting.

4. The method for setting an automatic power generation control model for intermittent energy interconnection according to claim 2, wherein in the step b, if there is a wind power source, collecting wind power supply time-amplitude (t sample and Step c; No step (:.

5. The method for designing an automatic power generation control model for intermittent energy grid-connected according to claim 2, wherein in the step c, if there is a photovoltaic power source, collecting the time-amplitude of the photovoltaic power source (, ^ sample and Perform step mountain or proceed to step d.

6, intermittent energy claim 2 design method for automatic generation control model in grid ¾ claim, wherein said step (d), if the same wind power and solar power, for wind and solar power source (ί _Β, ν _η ) Sample superposition effect analysis and proceed to step e _; otherwise proceed to step e.

7. The method for designing an automatic power generation control model for intermittent energy grid-connected according to claim 2, wherein in the step e, the source sample space of the two-dimensional disturbance domain of the intermittent energy source is represented by the following formula -

. . . (t, , _v „),)

(t, ' · . : I 2;

... U"

Where: (t, _: , _VE ) is a set of samples, indicating that the maximum wind power fluctuation amplitude obtained under the time span of t _n is v _n , : 2, 3 —.

8. The method for designing an automatic power generation control model for intermittent energy integration according to claim 2, wherein in the step f, the value of the diagonal sample from the source sample space is expressed by the following formula: , two passes -| , , I ^ °

9. The method for designing an automatic power generation control model for intermittent energy grid-connected according to claim 2, wherein in the step g, the formula 3 is the obtained intermittent energy source time-amplitude two. Dimension source.

10. The method for designing an automatic power generation control model for intermittent energy grid-connected according to claim i, wherein the step Β Φ, based on an exchange power deviation evaluation criterion, analyzes power grid fluctuation characteristics under disturbance; Two-dimensional perturbation domain

(^, ν^ as the disturbance amount. Analyze the power fluctuation characteristics of the grid when there is no automatic power generation control AGC system under the disturbance amount.

11. The method for designing an automatic power generation control model for intermittent energy grid-connected according to claim 10, characterized in that: analyzing the power characteristics of the power grid comprises the following steps:

(1) The amount of change in the sectional section power is counted, that is, the following changes are counted -

I ^{Δ /} 3⁄4 moving zone I

ί Λ !

₌ I ^ disturbance zone 1 I @,

Wherein: A _¾ a sectional view of the power change of the disturbance _zone; Δ ΐ βι power change a cross-sectional area i is ^{undisturbed, i ::: l, 2 · ·} · η;

Moving zone 'i; disturbance zone i <. ⁰

Otherwise, the exchange power deviation between the disturbance zone and the non-disturbance zone is the same as the symbol, namely:

^Δ 3⁄4 moving zone ' ^Δ 3⁄4 disturbance zone ⁰ 6;

Then record the area and query the tie line that causes the exchange power deviation between the disturbance zone and the non-disturbance zone to be the same symbol, and reduce the crew of the tie line.

12. The method for designing an automatic power generation control model for intermittent energy grid-connected according to claim 1, wherein in the step C, the target of the distribution scheme of the automatic power generation control AGC system unit is the cross-section tie line power deviation. Return to zero with the frequency deviation in the secondary frequency modulation stage, ie:

13. The method for designing an automatic power generation control model for intermittent energy grid-connected according to claim i, wherein in the step D, a ^V " in a two-dimensional disturbance domain is used as a disturbance amount, and the power system Total spare capacity|3⁄4

Where: indicates the secondary reserve capacity of the control area; / is the maximum fluctuation of the load at the same time scale as the wind power: The standby capacity scheme is used to recover the power of the section power exchange, the frequency recovery, and the regional deviation control the zeroing of the ACE signal Expressed by:

Where: Δ \ 4 and ACE are the discriminant indicators of the effect of the secondary frequency modulation in the secondary frequency modulation time; t take the minute level according to the adjustable capacity and adjustment speed of the vanadium group of the automatic power generation control AGC system for the power type of the frequency modulation determine.

14. The method for designing an automatic power generation control model for intermittent energy grid-connected according to the invention, wherein in the step E, the unit output of the automatic power generation control AGC system control area satisfies the following formula:

ACE Af < 0 10; Its Φ, C£ represents the regional deviation control signal of the control region; 4/' denotes the power system frequency deviation - exchanges power recovery with link line, frequency recovery and regional deviation control ACE signal return to zero: three indicators For the evaluation basis, namely ΔΡ, Δ and ACE, the speed of the three indicators, the magnitude of the deviation, and the unit output coordination between the control areas are the evaluation criteria, and the control strategy of the automatic power generation control AGC system is obtained.

15. The method for designing an automatic power generation control model for intermittent energy grid-connected according to the present invention, wherein in the step F, the maximum fluctuation amount (t _n , in the time range of the secondary frequency modulation of the wind power base is used. _Vn ) and large-scale off-grid of wind power (ί _νπκχ ;) is the source of disturbance, with the range of 1., '2% of the maximum peak load as the value range, and combined with the case of C £. > 0, compare the regional frequency of the control area Deviation setting, select the optimal frequency deviation coefficient of the control area.

16. The method of designing an automatic power generation control model for intermittent energy grid-connected according to claim 1, wherein in the step G, the parameter design comprises a natural frequency deviation coefficient design.