CN111898883A - Cascading failure risk assessment and prevention control method considering economic benefits - Google Patents
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Abstract
The invention relates to a cascading failure risk assessment and prevention control method considering economic benefits, wherein the cascading failure risk assessment finally obtains the power failure risk of cascading failure by establishing a line outage probability model based on real-time operation conditions, and by calculating cascading failure probability and calculating cascading failure consequences; in order to ensure the economy of preventive control and the rapidity of calculation, an economical control strategy flow is obtained by using a preventive control model. According to the method, a fault blocking strategy is provided through the evaluation of the cascading faults, and the cascading faults are prevented; and a more applicable stable control principle is provided on the basis of considering economic benefits.
Description
Technical Field
The invention relates to a cascading failure risk assessment and prevention control method considering economic benefits. Belongs to the technical field of electric power.
Background
With the increasing demand for electricity, the power grids are rapidly evolving. By the end of the 20 th century, the development of the world grid has entered the large-scale interconnected grid phase, forming a large synchronous grid with trans-regional or trans-national power transmission capabilities. Although the large-scale interconnected power grid solves the problem of optimal configuration of power resources, the risk of cascading failures of a power system is increased. In the world, a plurality of large-area power failure accidents are caused by cascading failures. Such as: the power failure is increased in the United states which occurs in 14 days in 8 months in 2003, line overload tripping is caused due to line tripping in high-temperature weather, and finally the system breakdown causes large power failure; in 2011, a power grid of 8 Japan, south China, Western America is broken down, and due to the fault of one 500 kV line under the condition of high temperature and heavy load, the transformer is tripped out of operation in an overload way caused by load transfer, so that a chain reaction is caused to finally cause heavy power failure; in 7/30 th and 7/31 th in 2012, two major power failure accidents occur in the indian power grid, which are caused by the tripping of 400kV tie line circuits of north and west power grids, and the load transfer of a system triggers chain reaction, so that the power grid is finally crashed; in 9.2005, large-area power failure occurs in the south of China at Hainan, in 1 to 2.2008, large-area and long-time power failure accidents occur in the south of China at Henan of the networking system in North China in 7.1.1.suns in 2006 due to ice disasters, and large-area power oscillation occurs in the south China at Henan of the networking system in North China in 2006.
Although the frequency of cascading failures is low, once they occur, the social and economic impact will be significant, and it is very necessary to study cascading failures and their preventive control. The evaluation of cascading failures is mainly to find potential failure elements of the power system in real time, analyze the correlation among failures of the elements, find possible failure development paths, and provide a failure blocking strategy in time on the basis to prevent cascading failures.
The three-way defense line is a great contribution of old generation electric power workers in China to the electric power technology, and is the basis of defense control of an electric power system, including relay protection and prevention control, emergency control and correction control. With the development of the power grid, the research on the stable control is not interrupted, and so far, a great deal of research results exist. Transient stability early warning and prevention control system based on the expected accident set is established, and the transient stability level of the system is improved by adjusting system control variables and reasonably arranging operation modes. In addition, for complex faults, a transient stability prevention control method based on trajectory sensitivity is proposed in the literature, and the prevention control problem is converted into a nonlinear programming problem taking the active output of the generator as a control quantity. Meanwhile, the research of emergency control is gradually developed from the traditional remote cutting and joint cutting based on offline calculation of a policy table into OPS-1 online pre-decision making fully utilizing the area criteria of parallel processing and expansion of a computer, and the concept of online pre-decision making and real-time matching enables the level of emergency control to be greatly stepped forward. At present, many researchers gradually begin to explore real-time prediction and real-time control methods for transient stability and power angle trajectory prediction on the basis of wide-area strategy information. In view of the complementarity between the preventive control and the emergency control, there is also a proposal in the literature for the execution of the coordination between the preventive control and the emergency control. There is also literature addressing the issue of coordination of emergency and corrective controls and emphasizing coordination of these two complementary control modes in terms of physical and economic characteristics based on the concept of risk. There are documents summarizing the coordination of each defense line and analyzing the problems to be considered in coordinating defense.
Although the scholars at home and abroad pay more and more attention to the study of cascading failures along with the increase of the complexity of the modern power grid, the control study aiming at the cascading failures is not much. The literature explains the structural characteristics of the power grids of the Chinese power grid and the Russian power grid in the prevention of the blackout accident from the perspective of three lines of defense of the blackout respectively, and provides some engineering prevention suggestions. On the basis of wide-area protection and control, documents summarize main measures of the current power grid about line overload, and finally point out that the smart power grid with self-healing capability can relieve cascading events, and an optimization analysis tool, a self-adaptive island splitting measure and relay protection hidden fault identification all play an important role in playing the function of the smart power grid. The researches are based on the traditional control principle and method to explore blackout prevention, and a more applicable stable control principle is provided on the basis of not considering economic benefits.
Disclosure of Invention
The invention aims to overcome the defects and provides a cascading failure risk assessment and prevention control method considering economic benefits.
The purpose of the invention is realized as follows:
a cascading failure risk assessment considering economic benefits is characterized in that: the cascading failure risk assessment model comprises the following steps:
s1: a line outage probability model based on real-time operating conditions;
s1.1: the line outage probability based on the fault factors of the line is as follows:
 |
in the formula:l om as a linemThe rate of aging failures per unit length of time,Len m for the length of the line m to be,Lineis a collection of lines in the system;
s1.2: line outage probability based on power flow transfer:
linenLines caused by power flow transfer after disconnectionmThe outage probability of (d) is expressed as:
 |
wherein the content of the first and second substances,
as a linenThe load factor of (d);
 |
in the formula:F n as a linenThe value of the tidal current before the cut-off,F max n,as a linenThe tidal current limit value of;
wherein the content of the first and second substances,A mn indicating linenPost-ablation linemCurrent variation and linemThe ratio of the original power flow;
 |
in the formula:F m as a linenLine before breakingmThe power flow value of (a) is,
as a linenLine after breakingmThe tidal current value of (c);
wherein the line load rate indexH mn Indicating linenPost-ablation linemA load factor;
 |
wherein the line coupling indexB mn Indicating linenPost-ablation linemCurrent variation and linenThe ratio of the original power flow;
 |
s1.3: line outage probability based on a latent fault;
line caused by hidden faultmThe outage probability of (d) may be expressed as:
 |
in the formula:p mis_b in order to protect the probability of a false action,p mis_d is the circuit breaker malfunction probability;
the probability of protection glitches can be expressed as:
 |
in the formula:p Z to protect the maximum false action probability;Z set in order to set the impedance,Z k to measure impedance;
；
s1.4: a line outage probability based on weather factors;
the weather change is processed into a random process of 2 weather conditions, namely normal weather conditions and severe weather conditions, because a long-distance transmission line can span a plurality of weather areas, the same line can be in different weather conditions at the same time, and under a two-state weather model, the accidental failure fault rate of the line in the ith weather area in unit lengthl ti Can be expressed as:
 |
in the formula: e is the fault proportion of the line in severe weather, N1 is the normal weather duration proportion, N2 is the severe weather duration proportion,
the method is a statistical average value of fault rates of the unit length of the line, zi represents the weather condition of a weather area i where the line is located, wherein zi =0 represents normal weather, and zi =1 represents severe weather;
the total accidental failure fault rate of the line is as follows:
 |
in the formula: i is the number of climate areas passed by the line, and li is the length of the line in the ith climate area;
for a two-state weather model, the line-alone outage probability is:
 |
s2: cascading failure probability calculation
Assuming that the grid has u cascading failure paths, the set of cascading failure paths and the cascading failure paths may be expressed as:
 |
|
 |
in the formula: tij is the jth fault link of the ith cascading fault path, and j =1, 2.. once.v;
taking the cascading failure path L1 as an example, the occurrence probability of the failure path is:
 |
in the formula: p1 is the initial failure probability, pj (j >1) is the probability of the current failure after the previous failure occurs;
s2.1 initial failure probability
The initial fault probability mainly considers the influence of the fault factors of the line, so that the initial fault probability is the outage probability of the line caused by the fault factors of the line, and then the linemThe initial failure probability of (a) is:
 |
s2.2 subsequent failure probability
When the circuit is onmIn case of severe overload, i.e. linemExceeds its limit value, the firstjLine after-1 faultmThe outage probability of (2) is the probability that overload protection does not reject and a circuit breaker does not reject, namely:
 |
in the formula:p inact_b in order to protect the probability of a refusal action,p inact_d the circuit breaker failure probability is obtained;
when the wireless path is heavily overloaded, the firstjLine after-1 faultmThe outage probability mainly considers the influence of trend transfer, hidden faults and weather factors, namely:
 |
s3: calculation of cascading failure consequences
Calculating cascading failures from the perspective of economic losses due to loadingL1 consequences ofS L1(ii) a Cascading failureLThe consequences of 1 are:
 |
in the formula:Min order to achieve the unit cost of the load in the power failure,Loss L1to cascading failureL1 the load loss of the system after occurrence;
s4: power outage risk of cascading failures
The product of the cascading failure probability and the cascading failure consequence is used as the cascading failure risk, and the cascading failure can be obtainedL1 power outage risk:
 |
。 |
a cascading failure prevention control method considering economic benefits is characterized by comprising the following steps: the cascading failure prevention control method comprises the following steps:
economic index for preventive controlCFor preventing and controlling cost and power failure risk indexRThe risk sum of each cascading failure path is used as a system operation risk indexE，EThe sum of the economic index and the power failure risk index;
 |
|
 |
|
 |
in the formula:K G 、K L andKrespectively a generator set, a load set and a cascading failure path set;P Gi 、
、a i controlling the front dynamo separately for preventioniActive power and preventive control rear generatoriActive power and generatoriAdjusting the cost coefficient;
、Mcontrolling afterload nodes for prevention respectivelyiLoad shedding amount and load loss cost coefficient;R Lk risk for cascading failure path i;
in order to take safety and economy into consideration and enable the control effect brought by control measures to be optimal, a prevention control model is provided as follows:
an objective function:
 |
constraint conditions are as follows:
 |
|
 |
|
 |
|
 |
in the formula:P Li controlling preload nodes for preventioniThe active load of (2);
andF ij,max respectively for preventive control of the rear circuitijCurrent and line ofijLimit values of the power flow;P Gi,min as a generatoriThe lower limit of the active power output is,P Gi,max as a generatoriThe upper limit of active power output.
Further, the implementation of the control strategy is carried out according to two priorities, wherein the priority 1 represents that only the output adjustment of the generator is carried out, and the priority 2 represents that the output adjustment and the load shedding adjustment of the generator are carried out; when the priority level 1 calculates the optimal solution, the whole control strategy is formed, the algorithm is finished, and the calculation of the priority level 2 is not carried out; when the priority level 1 does not obtain the optimal solution, the condition is not satisfied enough by the pairing adjustment of the generator, and therefore the adjustment calculation of the priority level 2 is carried out; if the priority 2 still does not obtain the optimal solution, the calculation is finished, and the system is determined to have no proper preventive control measures under the current running state and needs to be matched with the emergency control.
Further, a cascading failure risk assessment considering economic benefits, according to S4L1, the power failure risk of other cascading failure paths can be obtained through the calculation formula of the power failure risk.
Compared with the prior art, the invention has the beneficial effects that:
according to the cascading failure risk assessment and prevention control method considering economic benefits, a failure blocking strategy is provided through the assessment of cascading failures, and the cascading failures are prevented; and a more applicable stable control principle is provided on the basis of considering economic benefits.
Drawings
Fig. 1 is a flow chart of a preventive control strategy.
Detailed Description
The following description of the embodiments of the present invention will be made with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.
The invention relates to a cascading failure risk assessment and prevention control method considering economic benefits, which comprises a cascading failure risk assessment model and a cascading failure prevention control method;
the cascading failure risk assessment model comprises the following steps:
s1: a line outage probability model based on real-time operating conditions;
s1.1: the line outage probability is based on the fault factors of the line;
the line aging failure is mainly considered as a fault factor of the line, and the line outage fault rate l caused by the line aging failure can be a corresponding numerical value found in a line aging failure fault rate curve obtained through historical statistical data according to the operation age of the line under the current operation working condition.
Assuming that the power grid is in the same geographical and meteorological environment, the outage probability of the line is in direct proportion to the length of the line and the aging fault rate of the unit length in the same time, and the normalized numerical value of the product of all the line lengths and the aging fault rate of the unit length is taken as the outage probability of the line, and the following steps are carried out:
 |
(1) |
in the formula:l om as a linemThe rate of aging failures per unit length of time,Len m for the length of the line m to be,Lineis the collection of lines in the system.
S1.2: a line outage probability based on power flow transfer;
the probability of line outages due to power flow diversion depends on the load rate of the line and the effect of the line power flow changes on the other line power.
Definition of
As a linenThe load factor of (2) is as follows:
 |
(2) |
in the formula:F n as a linenThe value of the tidal current before the cut-off,F max n,is the current limit value of the line n.
The impact of line power flow changes on other line power may be determined using line power flow fluctuation indicators, line load rate indicators, and line coupling indicators.
Line tidal current fluctuation indexA mn Indicating linenPost-ablation linemCurrent variation and linemThe ratio of the original tidal current is larger, the larger the index is, the larger the line tidal current fluctuation is, and the following steps are included:
 |
(3) |
in the formula:F m as a linenLine before breakingmThe power flow value of (a) is,
as a linenLine after breakingmThe tidal current value of (c).
Line load rate indexH mn Indicating linenPost-ablation linemThe load factor is as follows:
 |
(4) |
line coupling indexB mn Indicating linenPost-ablation linemCurrent variation and linenThe larger the index of the ratio of the original trend is, the circuit is indicatednWithdrawing line pairmThe larger the influence of the tidal current change is, the following are:
 |
(5) |
linenLines caused by power flow transfer after disconnectionmThe outage probability of (d) may be expressed as:
 |
(6) |
s1.3: line outage probability based on a latent fault;
latent faults are an inherent defect in protective devices that manifests itself only when the system fails, resulting in improper disconnection of the protected components. When a line is disconnected and then the whole network power flow is redistributed, the line may be shut down due to protection or circuit breaker misoperation. Because the probability of the single recessive fault is very small, the probability of the multiple recessive faults is smaller, and therefore the circuit caused by the recessive faults is not considered in the textmThe outage probability of (d) may be expressed as:
 |
(7) |
in the formula:p mis_b in order to protect the probability of a false action,p mis_d is the circuit breaker malfunction probability.
For the case of protection against false operation, the distance protection is taken as an example, and the distance protection is assumed to be full-impedance protectionZ set In order to set the impedance,Z k to measure impedance.
According to the action characteristic of full impedance protection, the circular track divides the impedance complex plane into an inner part and an outer part which respectively correspond to an action area and a non-action area, and the circular track is in a critical action state. Assuming that the protection malfunction probability is 0 in the circle and the malfunction probability is the greatest at the circle, the malfunction probability linearly decreases with increasing measured impedance outside the circle, and when the measured impedance increases to 3Z set The probability of temporal false action is reduced, so the probability of protection false action can be expressed as:
 |
(8) |
in the formula:
，p Z to protect the maximum false action probability; the probability of a circuit breaker malfunction is related to the physical characteristics of the circuit breaker and can be considered as a constant.
S1.4: a line outage probability based on weather factors;
the transmission line operated in the actual power grid is exposed outdoors, and the failure rate of the transmission line is related to the weather condition. Under some extremely severe weather conditions such as thunderstorms, typhoons, ice and snow, the fault rate of the line is greatly increased. For simplification, the weather change is treated as a random process of 2 weather conditions, namely normal weather condition and severe weather condition, since a long-distance power transmission line can span a plurality of weather areas and the same line can be in different weather conditions at the same time, under a two-state weather model, the accidental failure rate of the line in the ith weather area in a unit lengthl ti Can be expressed as:
 |
(9) |
in the formula: e is the fault proportion of the line in severe weather, N1 is the normal weather duration proportion, N2 is the severe weather duration proportion,
is a statistical average value of fault rates of the unit length of the line, zi represents the weather condition of a climate area i where the line is located, wherein zi =0 represents normal weather, and zi =1 is shown in a tableShowing bad weather.
The total accidental failure fault rate of the line is as follows:
 |
(10) |
in the formula: i is the number of climate zones passed by the line, and li is the length of the line in the ith climate zone.
For a two-state weather model, the line-alone outage probability is:
 |
(11) |
s2: cascading failure probability calculation
Assuming that the grid has u cascading failure paths, the set of cascading failure paths and the cascading failure paths may be expressed as:
 |
(12) |
 |
(13) |
in the formula: tij is the jth failure link of the ith cascading failure path, and j =1, 2.
Taking the cascading failure path L1 as an example, the occurrence probability of the failure path is:
 |
(14) |
in the formula: p1 is the initial failure probability, pj (j >1) is the probability of the current failure after the previous failure occurred.
S2.1 initial failure probability
The initial fault probability mainly considers the influence of the fault factors of the line, so that the initial fault probability is the outage probability of the line caused by the fault factors of the line, and then the linemThe initial failure probability of (a) is:
 |
(15) |
s2.2 subsequent failure probability
Working as a circuitmIn case of severe overload, i.e. linemExceeds its limit value, the firstjLine after-1 faultmThe outage probability of (2) is the probability that overload protection does not reject and a circuit breaker does not reject, namely:
 |
(16) |
in the formula:p inact_b in order to protect the probability of a refusal action,p inact_d the probability of the circuit breaker failing to operate is obtained.
② when the wireless path is heavily overloaded, the firstjLine after-1 faultmThe outage probability mainly considers the influence of trend transfer, hidden faults and weather factors, namely:
 |
(17) |
s3: calculation of cascading failure consequences
Calculating cascading failures from the perspective of economic losses due to loadsL1 consequences ofS L1. WhereinS L1Consider mainly 2 aspects: cascading failureL1 economic loss of load and cascading failure caused by system disconnectionL1, the line overload caused by the overload of the line.
Cascading failureLThe consequences of 1 are:
 |
(18) |
in the formula:Min order to achieve the unit cost of the load in the power failure,Loss L1to cascading failureL1 the amount of system off-load after occurrence.
S4: power outage risk of cascading failures
The product of the cascading failure probability and the cascading failure consequence is used as the cascading failure risk, and the cascading failure can be obtainedL1 power outage risk:
 |
(19) |
by analogy, the power failure risk of other cascading failure paths can be obtained.
The cascading failure prevention control method comprises the following steps:
economic index for preventive controlCFor preventing and controlling cost and power failure risk indexRThe method is characterized in that the sum of risks of each cascading failure path is represented in the form of power failure risk variation due to the influence of control measures on an electric power system, the control measures have control cost, and in order to comprehensively measure the power failure risk and the variation condition of the control cost, a system operation risk index is definedEAnd makeEThe power failure risk index is the sum of the economic index and the power failure risk index.
In that
 |
(20) |
 |
(21) |
 |
(22) |
In the formula:K G 、K L andKrespectively a generator set, a load set and a cascading failure path set;P Gi 、
、a i controlling the front dynamo separately for preventioniActive power and preventive control rear generatoriActive power and generatoriAdjusting the cost coefficient;
、Mcontrolling afterload nodes for prevention respectivelyiLoad shedding amount and load loss cost coefficient;R Lk is the risk of a cascading failure path i.
In order to take safety and economy into consideration and enable the control effect brought by control measures to be optimal, a prevention control model is provided as follows:
an objective function:
 |
(23) |
constraint conditions are as follows:
 |
(24) |
 |
(25) |
 |
(26) |
 |
(27) |
in the formula:P Li controlling preload nodes for preventioniThe active load of (2);
andF ij,max respectively for preventive control of the rear circuitijCurrent and line ofijLimit values of the power flow;P Gi,min as a generatoriThe lower limit of the active power output is,P Gi,max as a generatoriThe upper limit of active power output.
To ensure economy of preventive control and rapidity of calculation, load shedding costsMA normal number large enough to ensure that the load shedding measure is added only when the generator cannot find the optimal solution is selected, and the priority of the generator output can be set to be higher than the load shedding measure. Specifically, as shown in fig. 1, the whole control strategy is implemented according to 2 priorities, where priority 1 indicates that only the output adjustment of the generator is performed, and priority 2 indicates that the output and the load shedding adjustment of the generator are performed; when the priority level 1 calculates the optimal solution, the whole control strategy is formed, the algorithm is finished, and the calculation of the priority level 2 is not carried out; when the priority level 1 does not obtain the optimal solution, the condition is not satisfied enough by the pairing adjustment of the generator, and therefore the adjustment calculation of the priority level 2 is carried out; if the priority 2 still does not obtain the optimal solution, the calculation is finished, and the system is determined to have no proper preventive control measures under the current running state and needs to be matched with the emergency control.
In the above embodiments, the present invention is described only by way of example, but those skilled in the art, after reading the present patent application, may make various modifications to the present invention without departing from the spirit and scope of the present invention.
Claims (4)
1. A cascading failure risk assessment considering economic benefits, characterized in that: the cascading failure risk assessment model comprises the following steps:
s1: a line outage probability model based on real-time operating conditions;
s1.1: the line outage probability based on the fault factors of the line is as follows:
in the formula: lambda [ alpha ]omFor aging failure rate per unit length, Len, of line mmLine is the length of Line m, and Line is the set of lines in the system;
s1.2: line outage probability based on power flow transfer:
after the line n is disconnected, the outage probability of the line m caused by the power flow transfer is represented as:
wherein eta isnIs the load factor of line n;
in the formula: fnFor the value of the current before the line n is cut, Fmax,nIs the tidal current limit of the line n;
wherein A ismnRepresenting the ratio of the power flow variation of the line m after the line n is cut off to the original power flow of the line m;
in the formula: fmIs the current value, F ', of line m before line n is opened'mThe tide current value of the line m after the line n is cut off;
wherein the line load rate index HmnRepresenting the load rate of the line m after the line n is cut off;
wherein the line coupling index BmnRepresenting the ratio of the power flow variation of the line m after the line n is cut off to the original power flow of the line n;
s1.3: line outage probability based on a latent fault;
the outage probability of line m due to a hidden fault can be expressed as:
pbm＝pmis_b+pmis_d
in the formula: p is a radical ofmis_bTo protect the probability of false actions, pmis_dIs the circuit breaker malfunction probability;
the probability of protection glitches can be expressed as:
in the formula: p is a radical ofZTo protect the maximum false action probability; zsetTo set impedance, ZkTo measure impedance; zset≤Zk≤3Zset；
S1.4: a line outage probability based on weather factors;
the weather change is processed into a random process of 2 weather conditions, namely normal weather conditions and severe weather conditions, because a long-distance transmission line can span a plurality of weather areas, the same line can be in different weather conditions at the same time, and under a two-state weather model, the accidental failure fault rate lambda of the line in the ith weather area in unit lengthtiCan be expressed as:
in the formula: for the fault rate of the line in severe weather, N1 is the normal weather duration rate, N2 is the severe weather duration rate,
the method is characterized in that the method is a statistical average value of fault rates of unit length of a line, zi represents the weather condition of a weather area i where the line is located, wherein the condition of zi equals 0 to represent normal weather, and the condition of zi equals 1 to represent severe weather;
the total accidental failure fault rate λ t of the line is:
in the formula: i is the number of climate areas passed by the line, and li is the length of the line in the ith climate area;
for a two-state weather model, the line-alone outage probability is:
pcm＝1-e-λtt
s2: cascading failure probability calculation
Assuming that the grid has u cascading failure paths, the set of cascading failure paths and the cascading failure paths may be expressed as:
L＝{L1,L2,…,Lu}
Li＝{Ti1,Ti2,…,Tiv}
in the formula: tij is the jth fault link of the ith cascading fault path, and j is 1, 2.
Taking the cascading failure path L1 as an example, the occurrence probability of the failure path is:
pL1＝p1p2p3...pv
in the formula: p1 is the initial failure probability, pj (j >1) is the probability of the current failure after the previous failure occurs;
s2.1 initial failure probability
The initial fault probability mainly considers the influence of the fault factor of the line, so that the initial fault probability is the line outage probability caused by the fault factor of the line, and the initial fault probability of the line m is as follows:
p1m＝pwm
s2.2 subsequent failure probability
When the line m is heavily overloaded, namely the power flow of the line m exceeds the limit value, the outage probability of the line m after the j-1 fault is the probability that the overload protection is not rejected and the breaker is not rejected, namely:
pjm＝(1-pinact_b)(1-pinact_d)
in the formula: p is a radical ofinact_bTo protect the probability of a false positive, pinact_dThe circuit breaker failure probability is obtained;
when a wireless line is seriously overloaded, the outage probability of the line m after the j-1 th fault mainly considers the influences of power flow transfer, hidden faults and weather factors, namely:
pjm＝pam+pbm+pcm
s3: calculation of cascading failure consequences
Calculating the consequence S caused by cascading failure L1 from the perspective of economic loss caused by loadL1(ii) a The consequences of the cascading failure L1 are:
SL1＝MLossL1
in the formula: m is the unit cost of the load at power failure, LossL1The system load loss after the cascading failure L1 occurs;
s4: power outage risk of cascading failures
The power failure risk of the cascading failure L1 can be obtained by taking the product of the cascading failure probability and the cascading failure consequence as the cascading failure risk:
RL1＝pL1SL1。
2. a cascading failure prevention control method considering economic benefits is characterized by comprising the following steps: the cascading failure prevention control method comprises the following steps:
the economic index C of preventive control is preventive control cost, the power failure risk index R is the risk sum of each cascading failure path, and the system operation risk index E is the sum of the economic index and the power failure risk index;
E＝C+R
in the formula: kG、KLK is a generator set, a load set and a cascading failure path set respectively; pGi、
aiRespectively preventing the active power of the generator i before control, the active power of the generator i after prevention and control and the adjustment cost coefficient of the generator i;
m is the load shedding amount and the load loss cost coefficient of the load node i after prevention and control respectively; rLkRisk for cascading failure path i;
in order to take safety and economy into consideration and enable the control effect brought by control measures to be optimal, a prevention control model is provided as follows:
an objective function:
min E＝C+R
constraint conditions are as follows:
in the formula: pLiControlling the active load of the front load node i for prevention;
and Fij,maxLimit values for the power flow of the line ij and the power flow of the line ij after preventive control, respectively; pGi,minAs a generatori lower limit of active power output, PGi,maxIs the upper limit of the active output of the generator i.
3. The economic-benefit-considered cascading failure risk assessment system according to claim 1, wherein: the power outage risk of the other cascading failure paths can be obtained from the formula for calculating the power outage risk of the cascading failure L1 in S4.
4. The economic-benefit-considered cascading failure prevention control method according to claim 2, characterized in that: the implementation of the control strategy is carried out according to two priorities, wherein the priority 1 represents that only the output adjustment of the generator is carried out, and the priority 2 represents that the output adjustment and the load shedding adjustment of the generator are carried out; when the priority level 1 calculates the optimal solution, the whole control strategy is formed, the algorithm is finished, and the calculation of the priority level 2 is not carried out; when the priority level 1 does not obtain the optimal solution, the condition is not satisfied enough by the pairing adjustment of the generator, and therefore the adjustment calculation of the priority level 2 is carried out; if the priority 2 still does not obtain the optimal solution, the calculation is finished, and the system is determined to have no proper preventive control measures under the current running state and needs to be matched with the emergency control.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110106321A1 (en) * | 2009-11-03 | 2011-05-05 | Spirae, Inc. | Dynamic distributed power grid control system |
| CN102214920A (en) * | 2011-06-10 | 2011-10-12 | 华北电力大学 | Circuit cluster-based method for analyzing grid cascading failure based on |
| CN104268410A (en) * | 2014-09-28 | 2015-01-07 | 合肥工业大学 | Cascading failure multi-stage dynamic game defense method |
| CN105391064A (en) * | 2015-12-11 | 2016-03-09 | 天津大学 | Accurate hidden failure model-based cascading failure risk evaluation method for power transmission system |
| CN106327034A (en) * | 2015-06-18 | 2017-01-11 | 中国电力科学研究院 | Cascading failure search and weak link analysis method based on operation reliability model |
-
2020
- 2020-07-16 CN CN202010685838.4A patent/CN111898883A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110106321A1 (en) * | 2009-11-03 | 2011-05-05 | Spirae, Inc. | Dynamic distributed power grid control system |
| CN102214920A (en) * | 2011-06-10 | 2011-10-12 | 华北电力大学 | Circuit cluster-based method for analyzing grid cascading failure based on |
| CN104268410A (en) * | 2014-09-28 | 2015-01-07 | 合肥工业大学 | Cascading failure multi-stage dynamic game defense method |
| CN106327034A (en) * | 2015-06-18 | 2017-01-11 | 中国电力科学研究院 | Cascading failure search and weak link analysis method based on operation reliability model |
| CN105391064A (en) * | 2015-12-11 | 2016-03-09 | 天津大学 | Accurate hidden failure model-based cascading failure risk evaluation method for power transmission system |
Non-Patent Citations (3)
| Title |
|---|
| 丁明 等: "基于事故链及动态故障树的电网连锁故障风险评估模型", 《中国电机工程学报》 * |
| 丁明 等: "基于风险评估的电力系统连锁故障协调控制模型", 《电力系统自动化》 * |
| 姜臻 等: "一种基于粒子群优化算法的转移潮流控制策略", 《电力系统自动化》 * |
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