CN102708411A - Method for evaluating risk of regional grid on line - Google Patents

Abstract

The invention provides a method for evaluating the risk of a regional grid on line by using a D5000 system, which comprises the following steps: (1) acquiring the grid operation data and the state of a system; (2) selecting an expected fault set and analyzing the fault; (3) judging the effect caused by the grid according to the expected fault, carrying out the step (4) if the power supplying risk appears, and otherwise, returning to the step (2); and (4) calculating the risk indicator and the prompting risk according to the risk indicator. According to the method for evaluating the risk of the regional grid on line, the probability of the current state of the system, the probability of the possibility of the fault and the severity of the fault are considered comprehensively, so as to help the dispatchers to analyze and find out the potential risk of the system.

Description

A method for online risk assessment of regional power grid

technical field

The invention belongs to the field of power systems, and in particular relates to an online risk assessment method for a regional power grid.

Background technique

The safety analysis module in EMS has long adopted the deterministic analysis framework proposed in the 1960s, but it cannot account for various random disturbances in the power system, and cannot fully describe the uncertainty of faults. The traditional power system reliability analysis uses the probability evaluation method to study the uncertainty of the power system, but its main application field is the long-term planning of the power system, which is mainly used for offline analysis, and cannot be used for real-time judgment of the power system operating status , and the purpose of operational risk assessment is to use the current grid operation and equipment information to predict the system operational risk for a period of time (minutes to several hours) in the future and provide preventive control strategies. Therefore, it is very important to carry out the research on the real-time online operation risk probability assessment model and algorithm of the power system to make full use of the power transmission capacity of the system while maintaining an appropriate safety margin.

The main purpose of applying the operation risk assessment technology in the dispatching department is to allow the operation dispatcher to clarify the possible risks of each decision and make a choice between risks and benefits. There are two research purposes: one is to quantitatively evaluate the uncertain factors in the operation of the power system and calculate the operation risk index, which is a cognitive process; the other is to study how to deal with risks in operation scheduling and make reasonable decisions, such as risk-based Optimal power flow, maintenance plan and network reconfiguration, etc., this is the transformation process. Therefore, it is very necessary to conduct an operational risk assessment for the dispatching operation department.

At present, many countries in the world have conducted a lot of research on the risk assessment of power system operation, but most of the methods are suitable for large-scale transmission network or offline grid planning research. The regional power grid belongs to the high-voltage distribution network, which is usually a ring network structure and operates in an open loop, that is, its feeder has the characteristics of radiation. After a fault, it is likely to cause network disconnection and load loss. Therefore, it is necessary to carry out online operation suitable for ground dispatching characteristics The risk probability assessment model and its algorithm research make it an auxiliary tool for dispatchers to analyze safety decisions, and it is very important to make full use of the power transmission capacity of the system while maintaining an appropriate safety margin.

The disadvantages of the existing on-line operational risk probability assessment models and algorithms suitable for geodesic surveys include: 1) Deterministic analysis methods (such as static safety analysis) cannot take into account various random disturbances of the power system, and cannot fully describe faults uncertainty. 2) The failure rate or outage rate of outdoor components does not consider factors such as weather and time. 3) At present, a lot of research has been done on the risk assessment of power system operation, but most of the methods are suitable for large-scale transmission network or offline grid planning research.

Applying the operation risk assessment function to the actual system needs to study the following issues: establish a component time-varying reliability model that can reflect the real-time operating conditions of the power system, construct an operation risk index system that can characterize the real-time reliability level in detail, and improve the accuracy of the algorithm , Quickly obtain real-time status data, improve the real-time performance of calculation and the coordination of calculation amount, etc. On the basis of the existing research results, this paper combines the characteristics of the online dispatching requirements and risk assessment of the regional power grid. The specific research contents are as follows:

1) Considering the characteristics of regional power grid online power supply risk assessment, research the content of regional grid online risk assessment, real-time data network modeling method, so that the operation risk probability assessment results can better reflect the actual operation of the system and meet the actual operation needs.

2) Considering the influence of various factors in the real-time operation of the power system, the influence of the external environment on the outage rate of outdoor components is studied, and the failure possibility model of outdoor components is established.

3) In order to meet the calculation speed requirements of the online computing software, and at the same time, the expected fault set can cover the faults that occur frequently and easily cause power supply risks, the optimization algorithm research of the expected fault set selection and fault analysis is carried out.

4) Research on power system fault severity assessment model based on utility theory. Based on the utility theory, a fault severity assessment model that conforms to the actual situation of the power system is established. The utility function of the fault severity should be able to reflect the psychological tolerance of the system operators to the consequences of the fault.

5) Quantitatively evaluate the uncertain factors in the operation of the power system, evaluate the operation of the power grid for specific risk indicators, and divide the risk levels according to the value of the risk indicators. The indicator calculation of the online power supply risk analysis of the regional power grid is mainly carried out for the steady state problem. The calculation content includes the overload risk index, the low voltage risk index, the loss of load risk index, etc. The system failure severity assessment model determines the calculation methods of various risk indicators.

Contents of the invention

In order to overcome the above-mentioned defects, the present invention provides an online risk assessment method for regional power grids, which is researched and developed for the auxiliary analysis requirements of regional power grid dispatching operation, and conducts relevant analysis and judgment based on network topology and real-time data to identify and monitor potential power supply risks in the power grid. The special operation mode, combined with the results of online static safety analysis, forms the expected failure set of risk assessment, and calculates various risk indicators of the system based on this. The calculation of risk indicators should comprehensively consider the probability of the current state of the system, the probability of failure, and the severity of failure to help dispatchers analyze and discover potential system risks.

In order to achieve the above object, the present invention provides a system based on D5000 to assess the risk of the power grid, and its improvement is that the method includes the following steps:

(1). Obtain power grid operation data and system status;

(2). Select the expected failure set and analyze the failure;

(3). Judging the consequences of the power grid based on the expected failure, if there is a power supply risk, proceed to step 4, otherwise return to step 2;

(4). Calculate the risk index and give risk warning according to the index.

In the preferred technical solution provided by the present invention, in the step 1, the power grid operation data includes: real-time operation section data, historical operation section data and future mode section data; real-time operation section data includes important user data and high-risk user data.

In the second preferred technical solution provided by the present invention, in the step 1, the system status information is obtained according to the outage model and real-time data of the system components.

In the third preferred technical solution provided by the present invention, the system state information includes the topological connection relationship of the power grid, the output and load of the unit.

In the fourth preferred technical solution provided by the present invention, the outage model of system components includes: overhead lines of transmission lines, cables, units, transformers, capacitors and reactors.

In the fifth preferred technical solution provided by the present invention, in the step 2, the method of selecting the expected failure set includes: the whole network N-1, using the visual man-machine interface to define the manual failure group, and identifying potential faults in the whole network The special operation mode of power supply risk scans and monitors, and automatically forms a list of fault groups that affect power supply safety according to the scan results.

In the sixth preferred technical solution provided by the present invention, the special operation mode includes single power substation, single transformer single line, series supply and busbar split operation.

In the seventh preferred technical solution provided by the present invention, in the step 2, the fault analysis is carried out by using the mixed AC and DC power flow algorithm.

In the eighth preferred technical solution provided by the present invention, in the step 4, the risk indicators include the risk of line overload, the risk of too low physical bus voltage and the risk of load loss.

In the ninth preferred technical solution provided by the present invention, in the step 4, the risk index calculation includes severity calculation and failure rate calculation.

In the tenth preferred technical solution provided by the present invention, the severity calculation formulas of the risk of line overload and the risk of too low physical bus voltage are represented by formula (1):

S _ev (E _i , X _f )=(Δx/X) ^2m (1)

Among them, Δx represents the limit of the line flow and bus voltage; X represents the upper limit of the safe operation of the line or the lower limit of the safe operation of the physical bus; 2m is used to overcome the "shielding"defect; E _i represents the i-th fault; X _f represents the operation mode of the system; the so-called shadowing refers to: a certain expected failure that causes many lines to be overloaded but not overloaded, the expected failure behavior index is equal to or higher than the expected accident behavior index that only a few lines are overloaded .

In the more preferred technical solution provided by the present invention, the severity calculation formula of the risk of loss of load is represented by formula (2):

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; ev</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Among them, ω _j represents the importance level of load j; C _i,j represents the reduction amount of load point j after fault i occurs; m _i represents the number of load reduction points after fault i occurs.

In the second preferred technical solution provided by the present invention, the formula for calculating the failure rate is as shown in formula (3):

${\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; r</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; )</span>{\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

表示室内元件停运概率取统计值；P_r(E_i)表示故障E_i发生的概率。Among them, w' represents the weight coefficient of the influence of weather on the failure rate of outdoor components;

Indicates that the probability of outage of indoor components is taken as a statistical value; P _r (E _i ) indicates the probability of fault E _i occurring.

Compared with the existing technology, the online risk assessment method of regional power grid provided by the present invention improves the standardization, flow, informatization, automation, interaction and intelligent level of power grid dispatching, and greatly improves the technical support of power grid dispatching Level and technological innovation, management innovation capabilities; real-time access to the actual state of the system operation, which not only reflects the actual operation of the system more accurately, but also reduces the amount of calculation for state selection; Faults that occur frequently and easily cause power supply risks, while reducing the workload and maintenance of manual participation; in addition, using the multi-processor of the workstation to introduce parallel computing, in node optimization, matrix inversion, node type conversion, etc. Algorithms have been improved and optimized to greatly increase the calculation speed and meet the requirements of online analysis and calculation; moreover, according to the characteristics of the regional power grid, the importance degree factor has been introduced, and the calculation model of the load loss severity has been successfully established, so that the loss of load The resulting fault severity model can not only reflect the physical characteristics of the regional power grid, but also reflect the importance of important users and high-risk users.

Description of drawings

Figure 1 is a flow chart of the regional power grid online risk assessment method.

Figure 2 is a schematic diagram of the regional smart grid dispatching technical support system.

Detailed ways

The definition of regional smart grid dispatching technical support system is as follows:

As shown in Figure 2, the functional framework of the regional smart grid dispatching technical support system (D5000 system) is divided into three levels: application class, application, and function. An application class is a collection used to complete a certain type of business, and is composed of a group of applications with similar or similar business requirements; an application is a collection used to complete a certain aspect of business, and is composed of a group of closely related functional modules ; A function is used to complete a specific business requirement, and usually consists of one or more services, and the minimum function may not have a service. This specification defines three types of applications and 15 applications, and each application consists of several functional modules. It can be seen from the above figure that the regional smart grid dispatching technical support system is oriented to various dispatching disciplines at the regional level, and the system applications are divided into three categories: real-time monitoring and analysis, dispatching planning and dispatching management. Among them, real-time monitoring and analysis applications are divided into: real-time monitoring and alarm, network analysis, intelligent analysis and auxiliary decision-making and other applications. This method is proposed based on the implementation method and theory of the power supply risk analysis module of the intelligent analysis and auxiliary decision-making unit.

General requirements of D5000 system:

The D5000 system should meet the safety protection requirements of the secondary system, be able to adapt to the needs of the development of the power grid, especially the development directions of large-scale operation and integration, and fully embody the characteristics of informatization, automation, interaction and intelligence.

Support horizontal system integration construction:

The construction of the regional smart grid dispatching technical support system should meet the standardization requirements of the dispatching business. Its support platform should follow the concept of application and data integration, and under the premise of complying with the secondary security protection system, construct a unified support message and service bus for the system. Operation and application function development provides a powerful, convenient and easy-to-use support environment to realize the integration of information resources and the sharing of information such as data and models among various systems and application functions within the dispatching business scope, as well as the value-added of application functions, and improve the system performance and efficacy.

Meet the coordinated operation of the vertical system:

The design and construction of the regional smart grid dispatching technical support system should fully consider the vertical relationship between the dispatching professional services, and realize the power grid model, equivalent model, equipment parameters, operation mode, maintenance plan, and power consumption plan between the upper and lower dispatchers. The vertical exchange of information, as well as the refined analysis of the power grid. At the same time, it also supports functions such as automatic voltage coordination control of the upper and lower levels, and joint anti-accident exercises.

Realize source-side maintenance and network-wide sharing:

The regional smart grid dispatching technical support system should meet the requirements of "source end maintenance and whole network sharing" to realize the integrated operation, maintenance and use of the system. The following requirements shall be supported but not limited to:

1) Data can be automatically associated, exchanged and used in a wide area.

2) The application function is distributed and implemented in a wide area, and the service is unified.

3) Maintenance realizes division of labor and sharing within a wide area.

Supporting Platform Functional Requirements

The system support platform should provide general technical support for the development, operation and management of various applications, provide unified exchange services, model management, data management, and graphic management, and meet the needs of real-time, quasi-real-time and production management services for power grid dispatching .

Provides an online risk assessment method for regional power grids. This method is developed for the auxiliary analysis needs of regional power grid dispatching operations. It conducts relevant analysis and judgment based on network topology and real-time data, identifies and monitors special operation modes with potential power supply risks in the power grid, and combines The results of online static safety analysis form the expected failure set of risk assessment, and based on this, various risk indicators of the system are calculated. The calculation of risk indicators should comprehensively consider the probability of the current state of the system, the probability of failure, and the severity of failure to help dispatchers analyze and discover potential system risks.

As shown in Figure 1, a regional grid online risk assessment method, the method is based on the regional smart grid dispatching technical support system, the risk-based security assessment method is introduced into the regional grid energy management system (EMS), according to the regional grid dispatching characteristics, The possibility and severity of accidents were quantified and analyzed to provide real-time risk information for dispatching and operating personnel.

The method comprises the steps of:

A. Establish a time-varying failure possibility model for components;

B. Obtain the system status;

C. Carry out expected failure set selection and failure analysis;

D. Calculate risk indicators and give risk reminders.

The regional smart grid dispatching technical support system is a new generation of power grid dispatching technical support system, which greatly improves the standardization, process, informatization, automation, interaction and intelligent level of power grid dispatching, and greatly improves the level of power grid dispatching. The level of technical support and the ability of technological innovation and management innovation.

The risk-based safety assessment method refers to a comprehensive measurement of the possibility and severity of the uncertain factors faced by the power system; it can also be defined as the product of the accident probability and the consequences of the accident; this method takes the accident The possibility and severity of the accidents were quantified.

In the step A, the outage model of the system components in the risk assessment calculation considers factors such as time correlation, so as to make it more consistent with the actual operation of the power system.

In the step B, because it is based on the regional smart grid dispatching technical support system, the actual state of the system operation can be obtained in real time, which not only reflects the actual operation of the system more accurately, but also reduces the amount of calculation for state selection.

In the step C, according to the real-time data scanning, the expected failure set is obtained, and the manual setting of the failure is used as a necessary supplement, which not only includes most of the failures that occur frequently and are likely to cause power supply risks, but also reduces the workload and maintenance of manual participation .

In the step C, in the fault analysis, the existing research results are used, the AC-DC hybrid algorithm is adopted, and the multi-processor of the workstation is used to introduce parallel computing, and the algorithm is carried out in terms of node optimization, matrix inversion, node type conversion, etc. Improvement and optimization, greatly increased calculation speed, to meet the requirements of online analysis and calculation.

In the step D, according to the characteristics of the regional power grid, the importance factor is introduced, and the calculation model of the severity of load loss is successfully established, so that the fault severity model caused by load loss not only reflects the physical characteristics of the regional power grid, but also reflects the importance of important users and high-risk users. degree of importance.

In the step D, the calculation of the system risk index reflects the tolerance of the safe operation of the power grid to various risks (low voltage, overload, load loss) in a weighted manner.

In the step C, the risk level is manually defined in advance, which is divided into three levels, which are sorted from light to heavy according to the severity: safety level, alert level, and standard-exceeding level; providing basis for risk warnings at all levels.

The grid operation data is as follows:

Real-time operation section data: read the current power grid model from state estimation, and read real-time telemetry data from SCADA, which can be used to analyze and count the special operation mode of the current power grid, and can also be used as the basic section for simulation settings.

Historical operation section data: Obtain the historical operation section data of the power grid from the saved historical data CASE as the analysis section.

Future mode section data: read the maintenance plan data, and generate future mode data sections based on the current real-time data section according to the maintenance plan and load forecast data settings, to analyze the special operation mode that may be caused by the maintenance plan.

Important User Monitoring

Important user monitoring monitors the load changes of important (high-risk) users, power-saving users, and large users in real time according to the predefined range, monitors the overloaded equipment exceeding the safety threshold in real time, and provides prompt information to the dispatcher.

Important user data: usually refers to failure or abnormal removal of the load (user), which will cause significant political impact and economic loss, or threaten personal safety and cause casualties, etc. It can be determined according to relevant regulations and the specific conditions of each power system.

High-risk user data: important loads (users) with the highest importance and risk.

Real-time running section data includes: important user data and high-risk user data.

Risk Rating

The risk level can be manually defined in advance, which can be divided into three levels, which are sorted from light to heavy according to the severity: safety level, alert level, and standard-exceeding level; providing basis for risk warnings at all levels.

algorithm design

Online risk assessment is currently mainly for the dispatching department, and only considers steady-state analysis. In the absence of timely weather data, the dispatcher inputs the severity of the weather based on experience. This algorithm does not consider the impact of manual decision-making. The basic steps are shown in the figure below : Outage model for power system components.

The capacity of the power plants that can be directly dispatched by the regional power grid is generally small, so the derating operation status of the generator is not considered, and the failure model adopts a two-state (operation and shutdown) model.

Transmission lines include overhead lines, cables, transformers, capacitors and reactors, etc. A two-state (operating and out-of-service) model is used to simulate these elements.

Selection and Analysis of Anticipated Fault Sets

The envisioned failure set is formed by the ensemble in the following three ways:

1) N-1 of the whole network;

2) The entire network scans and monitors special operation modes with potential power supply risks, such as single-line single-transformation, single-power substation, etc., and automatically forms a list of fault groups that may affect power supply safety according to the scanning results;

3) Using the visualized man-machine interface, the fault group definition is carried out by experienced tuners and operation analysts.

The expected fault sets automatically formed by the above 1) and 2) methods already include most of the faults that occur frequently and are likely to cause power supply risks, and the method 3) is only a necessary supplement, reducing the workload and maintenance of manual participation.

This software uses the research results of the existing online static safety analysis software in the fault analysis algorithm, which can meet the requirements of calculation speed. This fault analysis method adopts the AC-DC hybrid algorithm, and uses the multi-processor of the workstation to introduce parallel computing. The algorithm is improved and optimized in node optimization, matrix inversion, node type conversion, etc., and the calculation speed is greatly improved. This fault analysis method has been applied in some regional-level dispatching, provincial-level dispatching, and prefectural-level dispatching, and its correctness has been verified. After testing, for a network of 2000 computing nodes, it only takes 3 seconds to perform the N-1 scan calculation of the entire network line, transformer, and unit. With the increase of the limit, the calculation time increases slightly.

Risk Indicator Calculation

Under steady-state conditions, the operational risk indicators should be measured in three aspects: power unbalance, branch overload, and voltage over-limit.

1) Severity calculation

According to the basic calculation formula of the risk index (error! Reference source not found.), this paper gives three risk indicators suitable for the steady state analysis of the regional power grid: ①The risk of line overload; ②The risk of the physical bus voltage being too low; ③The risk of loss of load .

S _ev (E _i , X _f )=(Δx/X) ^2m corresponding to risk indicators ① and ②, where Δx represents the limit of line flow and bus voltage; X represents the upper limit of safe operation of the line considered by system operators value or the lower limit of the safe operation of the physical busbar; the superscript 2m is used to overcome the "shading" defect.

其中ω_j表示负荷j的重要水平；C_i，j表示发生故障i后负荷点j的削减量；m_i表示发生故障i后负荷削减点的个数。The power supply safety of important users and high-risk users is related to a series of social, political and economic issues. The severity of the fault caused by the power outage depends not only on the characteristics of the regional power grid itself, but also on the nature of the users causing the power outage. The importance of the load is classified according to the nature of the user, and an importance factor is introduced. Due to the lack of outage time, the outage loss evaluation index is not calculated, and only the load loss risk index is calculated, that is, corresponding to ③

Among them, ω _j represents the importance level of load j; C _i,j represents the reduction amount of load point j after fault i occurs; m _i represents the number of load reduction points after fault i occurs.

2) Calculation of failure rate

则基本运算式(错误！未找到引用源。)中 $P_r\left(E_i\right)=(1+w_i^{\&prime;}){\stackrel{\&OverBar;}{F}}_i.$ In the absence of statistical data and precise weather parameters, it is analogous to the definition of the utility function in economics (that is, using any number in the interval [0, 1] to describe the weather state, 0 is equivalent to sunny weather, 1 is equivalent to the most Severe weather, which reflects people’s comprehensive description of weather conditions), the failure rate of outdoor components is regarded as the failure rate of indoor components multiplied by a weight coefficient w′ of the influence of weather on the failure rate of outdoor components, and the outage probability of indoor components is taken as Statistics

Then in the basic expression (Error! Reference source not found.) $P_r\left({\mathrm{E.}}_i\right)=(1+w_i^{\&prime;}){\stackrel{\&OverBar;}{f}}_i.$

In the absence of statistical parameters and weather detailed parameters, the value of w′ is obtained by using the expert system according to the actual operating conditions, that is, using the operating experience of the dispatcher or the operation analyst and the sensory experience of the weather to formulate the typical parameters of the expert system, The dispatcher or operation analyst obtains w' from the expert system according to the weather conditions of the day.

Risk Level Definition

The risk level is divided into three levels according to the size of the risk index, which are safety level, warning level, and over-standard level. The calculation of the critical value of each level is based on the simulation calculation of the system equipment in different serious programs.

The risk index value is a quantitative display of the degree of system risk, but for the dispatcher, it is more hoped to use the risk index value to know the operating status of the system. For this reason, the risk level is manually defined in advance, which can be divided into three levels, according to the severity The order from light to heavy is: safety level, alert level, over-standard level. Based on the judgment opinions of power system experts and power department dispatchers on the system operation status, the online risk level predefined scheme is as follows: based on the real-time operation section, when a single expected fault occurs, when the number of system out-of-limit equipment is greater than or equal to the standard, it is over-standard Level; when the percentage of system overloaded equipment to the total number of system equipment is greater than or equal to or the number of system overloaded equipment is greater than or equal to and the number of system overrunning equipment is less than, it is an alert level; otherwise it is a security level. All critical values for the above-mentioned division of risk levels provide a visual input and modification interface, which facilitates the flexible application of dispatching and operating personnel.

It should be declared that the contents and specific implementation methods of the present invention are intended to prove the practical application of the technical solutions provided by the present invention, and should not be construed as limiting the protection scope of the present invention. Those skilled in the art may make various modifications, equivalent replacements, or improvements under the inspiration of the spirit and principles of the present invention. But these changes or modifications are all within the protection scope of the pending application.

Claims (13)

1. the online methods of risk assessment of area power grid is assessed power grid risk based on the D5000 system, it is characterized in that said method comprises the steps:

(1). obtain operation of power networks data and system state;

(2). carry out that forecast failure collection is chosen and fault analysis;

(3). based on forecast failure the consequence that electrical network causes is judged, then carry out step 4 if the power supply risk occurs, otherwise return step 2;

(4). the calculation risk index, carry out indicating risk according to index.

2. method according to claim 1 is characterized in that, in said step 1, the operation of power networks data comprise: real time execution profile data, history run profile data and following mode profile data; The real time execution profile data comprises responsible consumer data and high-risk user data.

3. method according to claim 1 is characterized in that, in said step 1, stoppage in transit model and real time data according to system element obtain system status information.

4. method according to claim 3 is characterized in that, system status information comprises topological connection relation, unit output and the load of electrical network.

5. method according to claim 3 is characterized in that, the stoppage in transit model of system element comprises: the overhead transmission line of transmission line of electricity, cable, unit, transformer, capacitor and reactor.

6. method according to claim 1; It is characterized in that; In said step 2; The mode of choosing forecast failure collection comprises: the whole network N-1, utilize visual man-machine interface to carry out the definition of artificial fault group and the special method of operation that has potential power supply risk in the whole network is carried out scanning monitoring, forming automatically according to scanning result influences the fault of power supply safety Groups List.

7. method according to claim 5 is characterized in that, the said special method of operation, single supply transformer station, monotropic single line, statements based on collusion and bus split operation.

8. method according to claim 1 is characterized in that, in said step 2, adopts alternating current-direct current mixed current algorithm to carry out fault analysis.

9. method according to claim 1 is characterized in that, in said step 4, risk indicator comprises that circuit overload risk, physics busbar voltage cross low-risk and lose the load risk.

10. method according to claim 1 is characterized in that, in said step 4, risk indicator is calculated and comprised that seriousness is calculated and failure rate is calculated.

11., it is characterized in that said circuit overload risk and said physics busbar voltage are crossed low-risk seriousness computing formula and represented with formula (1) according to claim 9,10 described methods:

S _ev(E _i，X _f)＝(Δx/X) ^2m(1)

Wherein, Δ x representes the out-of-limit amount of circuit trend, busbar voltage; X representes the higher limit of line security operation or the lower limit of physics bus safe operation; 2m is used to overcome " covering " defective; E _iRepresent i fault; X _fThe method of operation of expression system; What is called is covered and is meant: somely cause that not overladen forecast failure heavy duty appears but in many circuits, this forecast failure behavioral indicator is equal to or higher than on the contrary has only individual line to produce overladen forecast accident behavioral indicator.

12., it is characterized in that the seriousness computing formula of said mistake load risk is represented with formula (2) according to claim 9,10 described methods:

$S_{\mathrm{ev}}(E_i,X_f)=\underset{j=1}{\overset{m_i}{\mathrm{\&Sigma;}}}{\mathrm{\&omega;}}_j{C}_{i,j}---\left(2\right)$

Wherein, ω _jThe significant levels of expression load j; C _{I, j}The break down reduction of i afterload point j of expression; m _iThe i afterload of representing to break down is cut down the number of putting.

13. method according to claim 10 is characterized in that, said failure rate computing formula is suc as formula shown in (3):

$P_r\left(E_i\right)=(1+w_i^{\&prime;}){\stackrel{\&OverBar;}{F}}_i---\left(3\right)$

Wherein, w ' expression weather is to the weight coefficient of outdoor element failure rate influence degree; Expression chamber components stoppage in transit probability is got statistical value; P _r(E _i) expression fault E _iThe probability that takes place.

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