CN112036718B - Electric power system safety risk assessment method considering new energy uncertainty - Google Patents
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Abstract
The invention discloses a power system safety risk assessment method considering new energy uncertainty, which aims at multiple possible scenes generated by sampling new energy uncertain variables, performs scene clustering based on uncertain variable distances weighted by new energy plant station safety and stability influence factors, and can avoid the possibility of 'risk leakage' caused by selecting a small probability high risk scene and other key scenes to a greater extent; and respectively determining the maximum operation scene and the minimum operation scene for each scene subset according to the influence of the uncertain variable of the new energy on the safety and stability, and accurately evaluating the maximum value and the minimum value of the safety and stability operation risk. The method realizes the online evaluation of the safe and stable operation risk of the power system considering the uncertainty of new energy prediction, and can meet the requirements of calculation speed and accuracy.
Description
Technical Field
The invention relates to a power system safety risk assessment method considering new energy uncertainty, and belongs to the technical field of power system automation.
Background
With the rapid development of the installed capacity of new energy, the grid-connected scale of the new energy is gradually increased, and the influence of the uncertainty of the output of the new energy on the safe operation and control of the power system cannot be ignored. The prediction accuracy of the new energy power at the present stage is still unsatisfactory, and the large-scale new energy grid connection puts higher requirements on the safe operation of the power system.
Generally, on-line analysis and calculation of safe and stable operation trend are carried out in a power dispatching control center based on the current system operation mode, a power generation plan, an overhaul plan and load prediction data, but the conventional deterministic on-line safe and stable analysis method is no longer suitable for a large-scale new energy grid-connected system. For the processing of the uncertainty of the new energy output, a confidence interval method or a scenario method is generally adopted. The interval method determines the upper and lower boundaries of the uncertain quantity based on a certain confidence level, generates large and small operation modes of the power system for analysis and calculation, and has the problem that the calculation conclusion is too conservative. The scene method can sample the uncertain variables of the new energy to generate possible scenes, the uncertain variables are represented through a plurality of deterministic scenes, the operation risk of each deterministic scene is obtained through safety and stability analysis and calculation, the operation risk of all the deterministic scenes is synthesized to obtain the safe and stable operation risk of the system, and therefore the method for evaluating the safe and stable risk is adopted to deal with the uncertainty of the output of the new energy.
At present, the number of expected faults to be considered in online safety and stability analysis can reach thousands, and even if a cluster parallel computing technology is adopted, the analysis and calculation time for a deterministic scene also needs several minutes. The conventional scene method needs too many scenes for analysis and calculation, scene reduction and scene combination are usually performed at present based on the probability distance of each scene, but a small-probability high-risk scene and other key scenes may be missed to cause risk leakage, so that an accurate and reliable scene reduction and scene combination method needs to be provided, and safety and stability risk assessment is performed on the basis to meet the requirements on calculation speed and accuracy.
Disclosure of Invention
The purpose is as follows: in order to solve the problems of scene reduction and improper combination of a large number of scenes generated by sampling uncertain variables of new energy resources in the prior art, the invention provides a power system safety risk assessment method considering new energy uncertainty.
The technical scheme is as follows: in order to solve the technical problems, the technical scheme adopted by the invention is as follows:
a power system safety risk assessment method considering new energy uncertainty comprises the following steps:
step 1) obtaining future t s Generating plan of conventional unit, load prediction data, generating power prediction data of new energy plant station and N generated by sampling uncertain variable of generating power of new energy s Generating a future t based on a conventional unit power generation plan, load prediction data and new energy plant station power generation power prediction data in a new energy plant station output scene s A basic mode of operation of the time period; setting K as the number of the fault in the expected fault set, setting K =1, and turning to step 2);
step 2) carrying out safety and stability risk evaluation calculation on the fault K in a basic operation mode to obtain safety and stability influence factors of each new energy plant station under the fault K;
step 3) carrying out N by adopting the European distance of the new energy station output weighted by each new energy station safety and stability influence factor s Clustering individual scenes to obtain S T A subset of scenes;
step 4) sequencing safety and stability influence indexes of the scenes in each scene subset according to the uncertain variable of the new energy generated power, and respectively determining a maximum risk operation scene and a minimum risk operation scene;
and 5) respectively carrying out safety and stability risk evaluation calculation under the fault K on the maximum risk operation scene and the minimum risk operation scene of each scene subset under the fault K to obtain the maximum safety and stability operation risk value and the minimum safety and stability operation risk value of each scene subset under the fault K, summing the maximum safety and stability operation risk values of all the scene subsets to obtain the maximum safety and stability operation risk value under the fault K, and summing the minimum safety and stability operation risk values of all the scene subsets to obtain the minimum safety and stability operation risk value under the fault K.
Step 6), K '= K +1, if K' is smaller than or equal to the total number of faults of the expected fault set, step 2) is carried out, and otherwise step 7) is carried out;
step 7) counting the maximum value and the minimum value of the safe and stable operation risk of each scene subset under all faults in the expected fault set to obtain the future t of the power system s Safe and stable operation risk maximum and minimum of the period.
As a preferred scheme, the safety and stability influence factors of each new energy plant station comprise static safety and stability influence factors and transient safety and stability influence factors;
the calculation formula of the static safety and stability influence factor is as follows:
wherein, PF s.i Is a static safety and stability impact factor, N, of the ith new energy plant h For the number of heavily loaded branches with a fault of K, S i.j Sensitivity of the i-th new energy station output to the active power of the heavy-load branch j, LF j Is the square of the load rate of the heavy load branch j;
the transient safety and stability influence factor calculation formula is as follows:
if X A.i ＞X S.i And if the + delta X and the delta X are the threshold values of the electrical distance, judging that the new energy plant station i belongs to the critical group, and calculating a transient safety and stability influence factor PF of the new energy plant station i according to the following formula t.i ：
PF t.i ＝1/X S.i
If X is S.i ＞X A.i And + delta X, judging that the new energy plant station i belongs to the rest group, and calculating a transient safety and stability influence factor of the new energy plant station i according to the following formulaPF t.i ：
PF t.i ＝1/X A.i
Wherein, the comprehensive electrical distance X between the new energy station bus and all the generator buses in the critical group S.i And the comprehensive electrical distance X between all the generator buses in the rest group A.i ；
Wherein alpha is j Generator j transient state power angle stability participation factor, x, in critical group provided for EEAC i.j Is the electrical distance, N, between the j bus of the generator and the i bus of the related new energy plant station CC The number of generators in the critical group; alpha (alpha) ("alpha") k For the generator k transient power angle stability participation factor, x, in the rest of the group i.k Is the electrical distance, N, between the generator k bus and the associated new energy plant station i bus RC The number of generators in the rest group.
As a preferred scheme, the european distance calculation formula of the new energy station output weighted by the safety and stability influence factor of each new energy station is as follows:
wherein D is ij Is the distance between the jth scene and the ith cluster center, N W Number of new energy plants, PF k Is the kth new energy station safety and stability influence factor, if the static safety and stability risk assessment is carried out, the kth new energy station safety and stability influence factor is the static safety and stability influence factor, namely PF k ＝PF s.i (ii) a If the risk evaluation of the transient safety and stability is carried out, the risk evaluation is the influence factor of the transient safety and stability, namely PF k ＝PF t.i ，P j.k For the kth new energy plant in the jth sceneStanding force, P i.k And outputting power for the kth new energy plant station of the ith clustering center.
Preferably, N is s The clustering of each scene adopts a K-Means clustering method, and the number of classes is preset.
As a preferable scheme, the calculation formula of the index of the influence of the uncertain variable of the new energy power generation power on the safety and stability is as follows:
wherein II i.j The safety and stability impact size index, N, of the jth scene in the ith class scene subset W Number of new energy plants, PF k Is the kth new energy station safety and stability influence factor, if the static safety and stability risk assessment is carried out, the kth new energy station safety and stability influence factor is the static safety and stability influence factor, namely PF k ＝PF s.i (ii) a If the risk assessment of the transient safety and stability is carried out, the risk assessment is the transient safety and stability influence factor, namely PF k ＝PF t.i ，P j.k Output, P, for the kth new energy plant station in the jth scene i.k And outputting the power of the kth new energy plant station of the ith type scene clustering center.
As a preferred scheme, the maximum risk operation scenario is a scenario corresponding to the maximum value of the safety and stability impact size index in each category of scenario subset, and the minimum risk operation scenario is a scenario corresponding to the minimum value of the safety and stability impact size index in each category of scenario subset.
As a preferred scheme, the maximum safe and stable operation risk value of each type of scene subset under the fault K is the severity obtained by entering the maximum risk operation scene in each type of scene subset under the fault K into safety evaluation calculation;
for the fault subjected to static safety risk assessment, the safety stability margin range obtained by the safety stability assessment calculation of the fault K is [ -100, +100], the severity is segmented and converted according to the level of the safety stability margin, and the calculation formula of the severity is as follows:
wherein eta is a safety and stability evaluation margin in percentage; alpha is alpha 1 、α 2 、……、α 6 For segmenting the conversion coefficient, and alpha 1 ＜α 2 ＜α 3 ＜α 4 ＜α 5 ＜α 6 ＜0；
For faults subjected to transient safety and stability risk assessment, the severity of the faults is assessed according to the total loss load after the faults and the grid shedding amount of the new energy source unit, which are obtained by the safety and stability assessment calculation of the fault K, the action modeling of a second defense line safety control device and a third defense line low-frequency low-voltage load shedding and splitting device is considered in the fault time domain simulation calculation, and the load loss directly caused by the faults and the load loss cut by the second and third defense line safety automatic devices are counted; and simultaneously, considering the frequency of the new energy unit and the total unit amount of the unit for cutting the voltage protection action, and respectively multiplying the total load amount and the net-off amount of the new energy unit by corresponding cost coefficients and then adding and summing the products to obtain the severity of the fault.
As a preferred scheme, the minimum safe and stable operation risk value of each type of scene subset under the fault K is the severity obtained by entering the minimum risk operation scene into the safety evaluation calculation in each type of scene subset under the fault K;
for the fault subjected to static safety risk assessment, the safety stability margin range obtained by the safety stability assessment calculation of the fault K is [ -100, +100], the severity is segmented and converted according to the level of the safety stability margin, and the calculation formula of the severity is as follows:
wherein eta is a safety and stability evaluation margin in percentage; alpha is alpha 1 、α 2 、……、α 6 For segmenting the conversion coefficient, and alpha 1 ＜α 2 ＜α 3 ＜α 4 ＜α 5 ＜α 6 ＜0；
For faults subjected to transient safety and stability risk assessment, the severity of the faults is assessed according to the total loss load after the faults and the grid shedding amount of the new energy source unit, which are obtained by the safety and stability assessment calculation of the fault K, the action modeling of a second defense line safety control device and a third defense line low-frequency low-voltage load shedding and splitting device is considered in the fault time domain simulation calculation, and the load loss directly caused by the faults and the load loss cut by the second and third defense line safety automatic devices are counted; and simultaneously, considering the frequency of the new energy unit and the total unit amount of the unit for cutting the voltage protection action, and respectively multiplying the total load amount and the net-off amount of the new energy unit by corresponding cost coefficients and then adding and summing the products to obtain the severity of the fault.
Preferably, the power grid system is in the future t s And the maximum safe and stable operation risk value in the time interval is the sum of the maximum safe and stable operation risk values under all faults.
Preferably, the power grid system is in the future t s And the minimum safe and stable operation risk value in the time period is the sum of the minimum safe and stable operation risk values under all faults.
Has the advantages that: according to the electric power system safety risk assessment method considering the uncertainty of the new energy, the scene clustering is carried out on the basis of the uncertain variable distance weighted by the safety and stability influence factors of the new energy plant station aiming at a plurality of possible scenes generated by sampling the uncertain variables of the new energy, so that the possibility of risk leakage caused by selecting a small probability high risk scene and other key scenes can be avoided to a large extent; and respectively determining the maximum operation scene and the minimum operation scene for each scene subset according to the influence of the uncertain variable of the new energy on the safety and stability, and accurately evaluating the maximum value and the minimum value of the safety and stability operation risk. The method realizes the online evaluation of the safe and stable operation risk of the power system considering the uncertainty of new energy prediction, and can meet the requirements of calculation speed and accuracy.
Drawings
FIG. 1 is a schematic flow diagram of the process of the present invention.
Detailed Description
The present invention will be further described with reference to the accompanying drawings.
As shown in fig. 1, a method for evaluating security risk of an electric power system considering uncertainty of new energy includes the following steps:
1) Obtaining future t s Generating plan of conventional unit, load prediction data, generating power prediction data of new energy plant station and N generated by sampling uncertain variable of generating power of new energy s Generating future t based on the power generation plan of the conventional unit, the load prediction data and the power generation power prediction data of the new energy plant station in the output scene of the new energy plant station s A basic mode of operation of the time period; setting K as the number of the fault in the expected fault set, setting K =1, and turning to step 2);
2) Performing safety and stability risk evaluation calculation on the fault K in a basic operation mode to obtain safety and stability influence factors of each new energy plant station under the fault K;
3) Carrying out N by adopting the European distance of the output of the new energy plant station weighted by the safety and stability influence factor of each new energy plant station s Clustering individual scenes to obtain S T A subset of scenes;
4) Sequencing the indexes of the safety and stability influence of the scenes in each scene subset according to the uncertain variable of the new energy power generation power, and respectively determining a maximum risk operation scene and a minimum risk operation scene;
5) And respectively carrying out safety and stability risk evaluation calculation under the fault K on the maximum risk operation scene and the minimum risk operation scene of each scene subset, obtaining the maximum safety and stability operation risk value and the minimum safety and stability operation risk value of each scene subset under the fault K, summing the maximum safety and stability operation risk values of all the scene subsets to obtain the maximum safety and stability operation risk value under the fault K, and summing the minimum safety and stability operation risk values of all the scene subsets to obtain the minimum safety and stability operation risk value under the fault K.
6) K '= K +1, if K' is less than or equal to the total number of faults of the expected fault set, step 2) is carried out, and otherwise step 7) is carried out;
7) Counting the maximum value and the minimum value of the safe and stable operation risk under all faults in the expected fault set to obtain the future t of the power system s Safe and stable operation risk maximum and minimum of the period.
The method for calculating the influence factors of the safety and stability of each new energy plant station under the fault K in the step 2) is as follows:
for the fault of static safety and stability risk assessment, the safety and stability influence factor calculation formula of each new energy plant station is as follows:
wherein, PF s.i Is a static safety and stability impact factor, N, of the ith new energy plant h For the number of heavily loaded branches with a fault of K, S i.j Sensitivity of the i-th new energy station output to the active power of the heavy-load branch j, LF j Is the square of the loading rate of the heavy load branch j.
And for the fault subjected to transient safety and stability risk assessment, calculating safety and stability influence factors of each new energy plant station according to the magnitude of the participation factors of the leading complementary group unit provided by the Extended Equal Area Criterion (EEAC). Respectively calculating the comprehensive electrical distance X between the bus of the related new energy plant station and all the generator buses in the critical group by adopting formulas (2) and (3) S.i And the comprehensive electrical distance X between all the generator buses in the rest group A.i ；
Wherein alpha is j Transient power angle stabilization participation factor, x, of generator j in critical group provided for EEAC i.j Is the electrical distance, N, between the j bus of the generator and the i bus of the related new energy plant station CC The number of generators in the critical group; alpha is alpha k For the generator k transient power angle stability participation factor, x, in the rest of the group i.k For generators k-bars and associatedElectrical distance between i buses of new energy plant, N RC The number of generators in the rest groups;
if X is A.i ＞X S.i And if the + delta X and the delta X are the threshold values of the electrical distance, judging that the new energy plant station i belongs to the critical group, and calculating a transient safety and stability influence factor PF of the new energy plant station i according to the following formula t.i ：
PF t.i ＝1/X S.i (4)
If X is S.i ＞X A.i And + delta X, judging that the new energy plant station i belongs to the rest group, and calculating a transient safety and stability influence factor PF of the new energy plant station i according to the following formula t.i ：
PF t.i ＝1/X A.i (5)
N in the step 3) s The clustering of each scene adopts a K-Means clustering method, the number of classes is preset, and the distance calculation formula between each scene and the clustering center is as follows:
wherein D is ij The distance between the jth scene and the ith cluster center, N W Number of new energy plants, PF k Is the kth new energy plant station safety and stability impact factor (if the static safety and stability risk assessment is carried out, the kth new energy plant station safety and stability impact factor is the static safety and stability impact factor, namely PF k ＝PF s.i (ii) a If the risk assessment of the transient safety and stability is carried out, the risk assessment is the transient safety and stability influence factor, namely PF k ＝PF t.i )，P j.k The power output, P, of the kth new energy station in the jth scene i.k And outputting power for the kth new energy plant station of the ith clustering center.
The method for determining the operation scene with the maximum risk and the operation scene with the minimum risk in each scene subset in the step 4) is as follows:
in each type of scene subset, calculating the index of the influence of the uncertain variable of the new energy power generation power on the safety and stability according to a formula (4) for all scenes:
wherein II i.j The safety and stability impact size index, N, of the jth scene in the ith class scene subset W Number of new energy plants, PF k Is the kth new energy plant station safety and stability impact factor (if the static safety and stability risk assessment is carried out, the kth new energy plant station safety and stability impact factor is the static safety and stability impact factor, namely PF k ＝PF s.i (ii) a If the risk assessment of the transient safety and stability is carried out, the risk assessment is the transient safety and stability influence factor, namely PF k ＝PF t.i )，P j.k The power output, P, of the kth new energy station in the jth scene i.k And outputting the power of the kth new energy plant station of the ith type scene clustering center.
And selecting the scene corresponding to the maximum value of the safety and stability influence size index as the maximum risk operation scene in each type of scene subset, and selecting the scene corresponding to the minimum value of the safety and stability influence size index as the minimum risk operation scene.
The safety and stability risk assessment calculation method under the fault K in the step 5) is as follows:
wherein R is K A safe and stable operation risk for fault K; p c.K Is the probability of occurrence of the fault K; s T All clustered scene subset sets are obtained; rho i Is the sum of all scene probabilities in the ith class of scene subset,
the severity of the fault K under the ith type scene is obtained, wherein the severity of the operation scene with the maximum risk corresponds to the maximum safe and stable operation risk of the fault K, and the severity of the operation scene with the minimum risk corresponds to the safe and stable operation of the fault KThe minimum value of the travel risk.
And respectively carrying out safety and stability evaluation calculation on the fault K on the operation scene with the maximum risk and the operation scene with the minimum risk of the ith class scene subset.
For the fault subjected to static safety risk assessment, the safety stability margin range obtained by the safety stability assessment calculation of the fault K is [ -100, +100], and the calculation formula for piecewise converting the severity according to the grade of the safety stability margin is as follows:
wherein eta is a safety and stability evaluation margin in percentage; alpha is alpha 1 、α 2 、……、α 6 For segmenting the conversion coefficient, and alpha 1 ＜α 2 ＜α 3 ＜α 4 ＜α 5 ＜α 6 ＜0。
And for the fault subjected to transient safety and stability risk assessment, evaluating the severity of the fault according to the total loss load after the fault and the grid disconnection amount of the new energy source unit, which are obtained by calculating the safety and stability assessment of the fault K. In the fault time domain simulation calculation, the action modeling of a second defense line safety control device and a third defense line low-frequency low-voltage load shedding and splitting device is considered, and the load loss directly caused by the fault and the load loss cut by the second and third defense line safety automatic devices are counted; and simultaneously, considering the frequency of the new energy unit and the total unit amount of the unit for cutting the voltage protection action, and respectively multiplying the total load amount and the net-off amount of the new energy unit by corresponding cost coefficients and then adding and summing the products to obtain the severity of the fault.
Future t of the power grid system in the step 7) s And the maximum value and the minimum value of the safe and stable operation risk of the time interval are respectively the sum of the maximum values of all the fault safe and stable operation risks in the expected fault set and the sum of the minimum values of all the fault safe and stable operation risks in the expected fault set.
The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.
Claims (10)
1. A power system safety risk assessment method considering new energy uncertainty is characterized by comprising the following steps: the method comprises the following steps:
step 1) obtaining future t s Generating plan of conventional units, load prediction data, generating power prediction data of new energy plant station and N generated by sampling uncertain variables of generating power of new energy s Generating a future t based on a conventional unit power generation plan, load prediction data and new energy plant station power generation power prediction data in a new energy plant station output scene s A basic mode of operation of the time period; setting K as the number of the fault in the expected fault set, setting K =1, and turning to step 2);
step 2) carrying out safety and stability risk evaluation calculation on the fault K in a basic operation mode to obtain safety and stability influence factors of each new energy plant station under the fault K;
step 3) carrying out N by adopting the European distance of the new energy station output weighted by each new energy station safety and stability influence factor s Clustering individual scenes to obtain S T A subset of scenes;
step 4) sequencing safety and stability influence indexes of the scenes in each scene subset according to the uncertain variable of the new energy generated power, and respectively determining a maximum risk operation scene and a minimum risk operation scene;
step 5) respectively carrying out safety and stability risk evaluation calculation under the fault K on the maximum risk operation scene and the minimum risk operation scene of each scene subset, obtaining the maximum safety and stability operation risk value and the minimum safety and stability operation risk value of each scene subset under the fault K, summing the maximum safety and stability operation risk values of all the scene subsets to obtain the maximum safety and stability operation risk value under the fault K, and summing the minimum safety and stability operation risk values of all the scene subsets to obtain the minimum safety and stability operation risk value under the fault K;
step 6), K '= K +1, if K' is smaller than or equal to the total number of faults of the expected fault set, step 2) is carried out, and otherwise step 7) is carried out;
step 7) counting the maximum value and the minimum value of the safe and stable operation risk of each scene subset under all faults in the expected fault set to obtain the future t of the power system s Safe and stable operation risk maximum and minimum of the period.
2. The method according to claim 1, wherein the method comprises the following steps: the safety and stability influence factors of each new energy plant station comprise static safety and stability influence factors and transient safety and stability influence factors;
the calculation formula of the static safety and stability influence factor is as follows:
wherein, PF s.i Is a static safety and stability impact factor, N, of the ith new energy plant h For the number of heavily loaded branches with a fault of K, S i.j Sensitivity of the i-th new energy station output to the active power of the heavy-load branch j, LF j Is the square of the load rate of the heavy load branch j;
the transient safety and stability influence factor calculation formula is as follows:
if X is A.i ＞X S.i And if the + delta X and the delta X are the threshold values of the electrical distance, judging that the new energy plant station i belongs to the critical group, and calculating a transient safety and stability influence factor PF of the new energy plant station i according to the following formula t.i ：
PF t.i ＝1/X S.i
If X is S.i ＞X A.i And + delta X, judging that the new energy plant i belongs to the rest group, and calculating a new energy plant i transient safety and stability influence factor PF according to the following formula t.i ：
PF t.i ＝1/X A.i
Wherein, the comprehensive electrical distance between the new energy station bus and all the generator buses in the critical groupX S.i And the comprehensive electrical distance X between all the generator buses in the rest group A.i ；
Wherein alpha is j Generator j transient state power angle stability participation factor, x, in critical group provided for EEAC i.j Is the electrical distance, N, between the j bus of the generator and the i bus of the related new energy plant station CC The number of generators in the critical group; alpha is alpha k For the generator k transient power angle stabilization participation factor, x, in the remaining groups i.k Is the electrical distance, N, between the generator k bus and the associated new energy plant station i bus RC The number of generators in the rest group.
3. The method according to claim 2, wherein the power system security risk assessment method considering the uncertainty of the new energy comprises: the Euclidean distance calculation formula of the new energy station output weighted by the safety and stability influence factors of each new energy station is as follows:
wherein D is ij Is the distance between the jth scene and the ith cluster center, N W Number of new energy plants, PF k Is the kth new energy station safety and stability influence factor, if the static safety and stability risk assessment is carried out, the kth new energy station safety and stability influence factor is the static safety and stability influence factor, namely PF k ＝PF s.i (ii) a If the risk assessment of the transient safety and stability is carried out, the risk assessment is the transient safety and stability influence factor, namely PF k ＝PF t.i ，P j.k The power output, P, of the kth new energy station in the jth scene i.k And outputting power for the kth new energy plant station of the ith clustering center.
4. The method according to claim 3, wherein the power system security risk assessment method considering the uncertainty of the new energy comprises: said N is s The clustering of each scene adopts a K-Means clustering method, and the number of classes is preset.
5. The method according to claim 2, wherein the power system security risk assessment method considering the uncertainty of the new energy comprises: the calculation formula of the index of the influence of the uncertain variable of the new energy power generation power on the safety and stability is as follows:
wherein II i.j The safety and stability impact size index, N, of the jth scene in the ith class scene subset W Number of new energy plants, PF k Is the kth new energy station safety and stability influence factor, if the static safety and stability risk assessment is carried out, the kth new energy station safety and stability influence factor is the static safety and stability influence factor, namely PF k ＝PF s.i (ii) a If the risk assessment of the transient safety and stability is carried out, the risk assessment is the transient safety and stability influence factor, namely PF k ＝PF t.i ，P j.k Output, P, for the kth new energy plant station in the jth scene i.k And outputting the power of the kth new energy plant station of the ith type scene clustering center.
6. The method according to claim 5, wherein the method comprises the following steps: the maximum risk operation scene is a scene corresponding to the maximum value of the safety and stability influence size index in each type of scene subset, and the minimum risk operation scene is a scene corresponding to the minimum value of the safety and stability influence size index in each type of scene subset.
7. The method according to claim 6, wherein the power system security risk assessment method considering the uncertainty of the new energy comprises: the maximum safe and stable operation risk value of each type of scene subset under the fault K is the severity obtained by entering safety evaluation calculation of the maximum risk operation scene in each type of scene subset under the fault K;
for the fault subjected to static safety risk assessment, the safety stability assessment calculation of the fault K obtains a safety stability margin range of [ -100, +100], and the severity is segmented and reduced according to the level of the safety stability margin, and the calculation formula of the severity is as follows:
wherein eta is a safety and stability evaluation margin in percentage; alpha is alpha 1 、α 2 、……、α 6 For segmenting the conversion coefficient, and alpha 1 ＜α 2 ＜α 3 ＜α 4 ＜α 5 ＜α 6 ＜0；
For faults subjected to transient safety and stability risk assessment, the severity of the faults is assessed according to the total loss load after the faults and the grid shedding amount of the new energy source unit, which are obtained by the safety and stability assessment calculation of the fault K, the action modeling of a second defense line safety control device and a third defense line low-frequency low-voltage load shedding and splitting device is considered in the fault time domain simulation calculation, and the load loss directly caused by the faults and the load loss cut by the second and third defense line safety automatic devices are counted; and simultaneously, considering the frequency of the new energy unit and the total unit amount of the unit for cutting the voltage protection action, and respectively multiplying the total load amount and the net-off amount of the new energy unit by corresponding cost coefficients and then adding and summing the products to obtain the severity of the fault.
8. The method according to claim 6, wherein the power system security risk assessment method considering the uncertainty of the new energy comprises: the minimum safe and stable operation risk value of each type of scene subset under the fault K is the severity obtained by entering the safety evaluation calculation of the minimum risk operation scene in each type of scene subset under the fault K;
for the fault subjected to static safety risk assessment, the safety stability margin range obtained by the safety stability assessment calculation of the fault K is [ -100, +100], the severity is segmented and converted according to the level of the safety stability margin, and the calculation formula of the severity is as follows:
wherein eta is a safety and stability evaluation margin in percentage; alpha (alpha) ("alpha") 1 、α 2 、……、α 6 For segmenting the conversion coefficient, and alpha 1 ＜α 2 ＜α 3 ＜α 4 ＜α 5 ＜α 6 ＜0；
For faults subjected to transient safety and stability risk assessment, the severity of the faults is assessed according to the total loss load after the faults and the grid shedding amount of the new energy source unit, which are obtained by the safety and stability assessment calculation of the fault K, the action modeling of a second defense line safety control device and a third defense line low-frequency low-voltage load shedding and splitting device is considered in the fault time domain simulation calculation, and the load loss directly caused by the faults and the load loss cut by the second and third defense line safety automatic devices are counted; and simultaneously, considering the frequency of the new energy unit and the total unit amount of the unit for cutting the voltage protection action, and respectively multiplying the total load amount and the net-off amount of the new energy unit by corresponding cost coefficients and then adding and summing the products to obtain the severity of the fault.
9. The method according to claim 7, wherein the power system security risk assessment method considering the uncertainty of the new energy comprises: future t of power grid system s And the maximum safe and stable operation risk value in the time period is the sum of the maximum safe and stable operation risk values under all faults.
10. The method according to claim 8, wherein the power system security risk assessment method considering the uncertainty of the new energy comprises: future t of power grid system s The minimum value of the safe and stable operation risk of the time interval is safe and stable operation wind under all faultsSum of the minimum of risk.
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