CN104898636A - Safety and stability control device reliability analysis method in consideration of multistate operation - Google Patents

Abstract

The invention discloses a safety and stability control device reliability analysis method in consideration of multistate operation, which belongs to the technical field of power system control. A hardware system structure of the safety and stability control device is firstly analyzed; a fault tree model for the safety and stability control device is then built based on a fault tree method, and the failure rate of the safety and stability control device is acquired; and finally, on the basis of Markov state space, a reliability evaluation model for the safety and stability control device is built, and the probability values of the safety and stability control device in four different operation states are calculated. The hardware system structure of the safety and stability control device and the importance degree of each stable control module for composing the device in the device are considered, the fault tree method and the Markov state space method are combined to carry out reliability evaluation on the safety and stability control device, the reliability degree of the device is thus judged, influences on reliability of the device by external faults are considered during the evaluation process, and the evaluation result is more objective and more accurate.

Description

A kind ofly consider the safety and stability control device fail-safe analysis method that multimode runs

Technical field

The invention belongs to technical field of electric power system control, be specifically related to the analysis method for reliability of the safety and stability control device in the control of a kind of power system safety and stability.

Background technology

China builds the extra-high voltage bulk transmission grid and DC transmission engineering that connect large-scale Energy Base and main loads center just energetically, forms the power network general layout of " three vertical three horizontal looped networks ".Safety and stability control device is positioned at the second defence line of China Power stability contorting, will be required the reliability possessing height.Convectional reliability assessment is mainly with based on " two-state hypothesis ", think that system is in complete normal operating conditions or total failure mode, and in Practical Project, system forms by having multi-mode parts, total failure mode can not be transitted directly to by complete normal condition, but have the process that a performance is degenerated gradually, namely between complete normal operating conditions and total failure mode, there is multiple intermediateness.In the present invention, think that safety and stability control device exists completely normal operation, recessive malfunction, recessive tripping and complete failure totally 4 kinds of states.

The recessive malfunction state of safety and stability control device and recessive tripping state cause hidden danger because device self exists the undiscovered or human factor of inherent shortcoming and cause, be referred to as hidden failure state, cause its fault being in hidden failure state and be then referred to as hidden failure.The hidden failure normally running timer when electric system can not have any impact to electric system, only just may be triggered under system is in abnormal pressure state (as ground short circuit fault, tide turns, voltage significantly fall) or severe running environment.Hidden failure weakens the reliability of safety and stability control device, once be triggered, can make failure of apparatus, can not realize due function, cause a large amount of loads, power loss, even large-area power-cuts, bring massive losses to national economy.

Therefore be necessary to assess the reliability of safety and stability control device, reliability especially by assessment safety and stability control device learns that device is in hidden failure shape probability of state size, so that take preventive measures ahead of time, reduce the possibility of failure of apparatus, ensure the safe and reliable operation of electrical network.

Summary of the invention

The present invention seeks to: in order to overcome the deficiency of convectional reliability appraisal procedure, a kind of safety and stability control device fail-safe analysis method that multimode runs of considering is proposed, the method is to assess safety and stability control device reliability based on fault tree and Markovian state space, according to the method can analyze safety and stability control device be in completely normal operation, recessive malfunction, recessive tripping and complete failure 4 kinds of different running statuses time the probability of stability, with the degree of reliability of this judgment means.

Specifically, the present invention realizes by the following technical solutions, comprises the following steps:

1) hardware system structure of safety and stability control device is analyzed;

2) set up the fault tree models of safety and stability control device based on Fault Tree, obtain the crash rate λ of safety and stability control device;

3) consider 4 kinds of running statuses of safety and stability control device: normal operating condition, recessive malfunction state, recessive tripping state and total failure mode completely, set up the Reliability Evaluation Model of safety and stability control device based on Markovian state space;

4) add up according to the history run of safety and stability control device, obtain related data, computationally secure stabilization control device be in completely normal, recessive malfunction, recessive tripping and complete failure 4 kinds of different running statuses time probable value.

Technique scheme is further characterized in that, described step 2) detailed process be:

201) based on step 1) in the analysis result of hardware system structure, set up the fault tree models of safety and stability control device;

202) safety and stability control device crash rate λ is asked for:

According to the reliability of electronic equipment Prediction Model of U.S. Military handbook " MIL-HDBK-217F ", the crash rate λ of each electronic devices and components in each steady control module of computationally secure stabilization control device _i, then the crash rate λ of each steady control module is asked by formula (1) _sCM:

${\mathrm{\λ}}_{\mathrm{SCM}}=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}{N}_i{\mathrm{\λ}}_i---\left(1\right)$

Wherein, λ _sCMfor the crash rate of single steady control module, λ _ibe the crash rate of i-th kind of components and parts, m is components and parts species number in steady control module, N _iit is total number of i-th kind of components and parts;

Give each steady control module weight according to steady control module for the importance of device, ask for the crash rate λ of device according to main control unit, I/O unit and the communication unit logical relation respectively formed between steady control module:

$\mathrm{\λ}={\mathrm{\λ}}_{\mathrm{main}}+{\mathrm{\λ}}_{\mathrm{IO}}+{\mathrm{\λ}}_{\mathrm{CU}}=\underset{j1=1}{\overset{J1}{\mathrm{\Σ}}}{\mathrm{\ξ}}_{j1}{\mathrm{\λ}}_{\mathrm{SCM}}^{j1}+\underset{j2=1}{\overset{J2}{\mathrm{\Σ}}}{\mathrm{\ξ}}_{j2}{\mathrm{\λ}}_{\mathrm{SCM}}^{j2}+\underset{j3=1}{\overset{J3}{\mathrm{\Σ}}}{\mathrm{\ξ}}_{j3}{\mathrm{\λ}}_{\mathrm{SCM}}^{j3}---\left(2\right)$

Wherein: λ is the crash rate of device; λ _main, λ _iOand λ _cUbe respectively the crash rate of main control unit, I/O unit and communication unit; ξ _j1for jth 1 main control unit surely controls module weight corresponding in safety and stability control device, ξ _j2for jth 2 I/O unit surely control module weight corresponding in safety and stability control device, ξ _j3for jth 3 communication units surely control module weight corresponding in safety and stability control device; for jth 1 main control unit surely controls the crash rate of module, for jth 2 I/O unit surely control the crash rate of module, for jth 3 communication units surely control the crash rate of module; J1, J2 and J3 are respectively the steady control module sum of main control unit, I/O unit and communication unit.

Technique scheme is further characterized in that, described step 3) in set up the Reliability Evaluation Model of safety and stability control device based on Markovian state space detailed process be:

301) determine that the precondition that analysis sets up the Reliability Evaluation Model of safety and stability control device based on Markovian state space is as follows:

1, the crash rate of safety and stability control device is step 2) in the failure of apparatus rate λ that asks for;

2, the fault of On-line self-diagnosis and supervision is set to detect coefficient as C ₁, NF malfunction number of times account for do not detect malfunction and tripping number of times and number percent be C ₂, then NF hidden failure malfunction rate C ₃c is divided with NF hidden failure tripping rate ₄be not:

C ₃＝C ₂(1-C ₁)λ

C ₄＝(1-C ₂)(1-C ₁)λ

The recessive malfunction fault of device and recessive tripping fault can be found when prophylactic repair to repair, if prophylactic repair rate is μ ₂;

3, the failure rate that safety and stability control device can check out is C ₅=C ₁λ, detecting fault restoration rate is μ ₁;

4, the rate of breakdown of the recessive tripping fault of triggering secure stabilization control device is λ _s, the rate of breakdown of the recessive malfunction fault of triggering secure stabilization control device is λ _ex;

5, can mutually shift between recessive malfunction state and recessive tripping state, recessive malfunction hidden danger is C to the rate of transform of recessive tripping hidden danger ₆, recessive tripping hidden danger is C to the rate of transform of recessive malfunction hidden danger ₇;

6, do not consider communication port problem, do not consider the locking failure problems of device, plant failure can return to serviceable condition after repairing, and above-mentioned failure rate and repair rate are constant;

7, can be repaired immediately after supposing protected element fault;

302) in step 301) on the basis of precondition determined, set up the Markovian state space diagram of safety and stability control device, obtain the Reliability Evaluation Model of safety and stability control device.

Technique scheme is further characterized in that, described step 4) in, computationally secure stabilization control device be in completely normal, recessive tripping, recessive malfunction and complete failure 4 kinds of different running statuses time the detailed process of probable value be:

401) according to step 302) in safety and stability control device Markovian state space diagram set up such as formula the state space equation shown in (3):

PT＝0

$\underset{i=1}{\overset{4}{\mathrm{\Σ}}}{p}_i=1---\left(3\right)$

Wherein, P=[p ₁, p ₂, p ₃, p ₄] be the plateau probability of each state, p ₁probability during corresponding normal operating condition completely, p ₂probability during corresponding recessive malfunction state, p ₃probability during corresponding recessive tripping state, p ₄probability during corresponding intrument complete failure; T is state transition probability density matrix, and its expression formula is:

$T=\left[\begin{array}{cccc}-(C_3+C_4+C_5)& C_3& C_4& C_5\\ {\mathrm{\μ}}_2& -({\mathrm{\μ}}_2+C_6+{\mathrm{\λ}}_{\mathrm{ex}})& C_6& {\mathrm{\λ}}_{\mathrm{ex}}\\ {\mathrm{\μ}}_2& C_7& -({\mathrm{\μ}}_2+C_7+{\mathrm{\λ}}_s)& {\mathrm{\λ}}_s\\ {\mathrm{\μ}}_1& 0& 0& -{\mathrm{\μ}}_1\end{array}\right]---\left(4\right)$

402) according to the history run of safety and stability control device, statistics obtaining step 302) in correlation parameter in state space graph and state transition probability density matrix T, in conjunction with the failure of apparatus rate λ tried to achieve, according to formula (3), formula (4) computationally secure stabilization control device be in completely normal, recessive malfunction, recessive tripping and complete failure 4 kinds of different running statuses time probable value.

Beneficial effect of the present invention is as follows: the present invention is analyzing on safety and stability control device hardware system structure point basis fully, Fault Tree and Markovian state space law are combined, proposes a kind of safety and stability control device Reliability Evaluation Model considering multimode operation characteristic.According to this model can analyze safety and stability control device be in completely normal operation, recessive malfunction, recessive tripping and complete failure 4 kinds of different running statuses time the probability of stability, with the degree of reliability of this judgment means, take preventive measures in time, the threat that the inefficacy of safety and stability control device is formed electrical network can be prevented, thus avoid bringing massive losses to electrical network and national economy.Consider the impact of extraneous fault on device reliability in evaluation process simultaneously, make assessment result have more objectivity, more precisely.

Accompanying drawing explanation

Fig. 1 is safety and stability control device fail-safe analysis method process flow diagram.

Fig. 2 is the fault tree models of safety and stability control device hardware system.

Fig. 3 is the Markovian state space diagram of safety and stability control device.

Embodiment

With reference to the accompanying drawings and in conjunction with example, the present invention is described in further detail.

As shown in Figure 1, safety and stability control device fail-safe analysis method of the present invention, comprises following step.

Step 1 in Fig. 1, analyzes the hardware system structure of safety and stability control device.For standardized production, a set of safety and stability control device is made up of a series of standard stabiliser control module (Stability Control Model, SCM), is divided into main control unit, I/O unit and communication unit according to function difference.

Main control unit is the hinge unit of system, is responsible for analysis, decision-making and output and controls, provide the man-machine interface of system, telecommunication management etc. simultaneously.I/O unit is device and the direct interface of outside, is responsible for sampling analysis and exports exporting, be connected by optical fiber with main control unit, mainly complete the collection of data, calculating, cell failure judgement and the information interaction with mainframe box.The data that main control unit is sent by optical fiber interface are changed by communication unit, to access SDH or PCM equipment, are transferred to offside by digital communications network.Main control unit mainly comprises power module, main control unit CPU module, host computer module, optical communication expansion module, outlet module, forceful electric power are opened and opened to enter mould into module and mould and go out module into module, light current; I/O unit mainly comprises power module, interchange head mould part, filtering module, I/O unit CPU module, outlet module, opens into module; Communication unit comprises communication master control borad module, communication interface board module.

In Practical Project, the composition of each unit of safety and stability control device of different engineering is surely controlled module and is not quite similar, main control unit as the safety and stability control device at openning station, pavilion is opened formed into module and main control unit CPU module by power module, host computer module, outlet module, light current, enters mould go out other modules such as module, optical communication expansion module without mould.Know that the hardware system of device is formed so must analyze before the crash rate of computationally secure stabilization control device, so just can obtain comparatively degree of accuracy crash rate.

Step 2 in Fig. 1, sets up the fault tree models of safety and stability control device based on Fault Tree, obtain the crash rate λ of safety and stability control device, its detailed process is:

Step 201: analyze based on the safety and stability control device hardware system structure in step 1, set up the fault tree models of safety and stability control device.The fault tree models of typical safety and stability control device as shown in Figure 2.

Step 202: ask for safety and stability control device crash rate λ:

Crash rate is one of important indicator of apparatus for evaluating reliability, is defined as device and not yet loses efficacy in this moment, and the probability lost efficacy occurs in the unit interval afterwards.Steady control module is made up of a large amount of electronic devices and components, and most component failure rate calculates will consider the factors such as basic failure rate, environmental coefficient, Thermal Stress Coefficient, quality coefficient, mature coefficient.The crash rate of certain components and parts concrete calculates some attributes that may also need to consider components and parts self, as transistor also needs to consider voltage stress coefficient and construction coefficient factor, capacitor also needs to consider electric capacity coefficient and resistance in series coefficient factor, and integrated circuit need consider circuit complexity crash rate and encapsulation complexity crash rate factor.When the part attribute of components and parts is not known, the general crash rate of searching these components and parts by its known attribute substitutes.

U.S. Military handbook " MIL-HDBK-217F " is the technical manual estimated about reliability of electronic equipment that US military is issued, and purchases relevant reliability of electronic equipment estimate in order to guidance with U.S. Department of Defense.This handbook was externally issued on November 2nd, 1991, had become the conventional method of electronic equipment being carried out to reliability prediction at present.The present embodiment also adopts the crash rate of the reliability of electronic equipment Prediction Model in this handbook to each steady control module of safety and stability control device to calculate, specific as follows:

According to the reliability of electronic equipment Prediction Model of U.S. Military handbook " MIL-HDBK-217F ", the crash rate λ of each electronic devices and components in each steady control module of computationally secure stabilization control device _i, then the crash rate λ of each steady control module is asked by formula (1) _sCM:

${\mathrm{\λ}}_{\mathrm{SCM}}=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}{N}_i{\mathrm{\λ}}_i---\left(1\right)$

Wherein, λ _sCMfor the crash rate of single steady control module, λ _ibe the crash rate of i-th kind of components and parts, m is components and parts species number in steady control module, N _iit is total number of i-th kind of components and parts;

After the crash rate obtaining each steady control module, give each steady control module weight according to steady control module for the importance of device, ask for the crash rate λ of device according to main control unit, I/O unit and the communication unit logical relation respectively formed between steady control module:

$\mathrm{\λ}={\mathrm{\λ}}_{\mathrm{main}}+{\mathrm{\λ}}_{\mathrm{IO}}+{\mathrm{\λ}}_{\mathrm{CU}}=\underset{j1=1}{\overset{J1}{\mathrm{\Σ}}}{\mathrm{\ξ}}_{j1}{\mathrm{\λ}}_{\mathrm{SCM}}^{j1}+\underset{j2=1}{\overset{J2}{\mathrm{\Σ}}}{\mathrm{\ξ}}_{j2}{\mathrm{\λ}}_{\mathrm{SCM}}^{j2}+\underset{j3=1}{\overset{J3}{\mathrm{\Σ}}}{\mathrm{\ξ}}_{j3}{\mathrm{\λ}}_{\mathrm{SCM}}^{j3}---\left(2\right)$

Wherein: λ is the crash rate of device; λ _main, λ _iOand λ _cUbe respectively the crash rate of main control unit, I/O unit and communication unit; ξ _j1for jth 1 main control unit surely controls module weight corresponding in safety and stability control device, ξ _j2for jth 2 I/O unit surely control module weight corresponding in safety and stability control device, ξ _j3for jth 3 communication units surely control module weight corresponding in safety and stability control device; for jth 1 main control unit surely controls the crash rate of module, for jth 2 I/O unit surely control the crash rate of module, for jth 3 communication units surely control the crash rate of module; J1, J2 and J3 are respectively the steady control module sum of main control unit, I/O unit and communication unit.

Step 3 in Fig. 1, for considering 4 kinds of running statuses of safety and stability control device: normal operating condition, recessive malfunction state, recessive tripping state and total failure mode completely, set up the Reliability Evaluation Model of safety and stability control device based on Markovian state space, detailed process is as follows:

301) determine that the precondition that analysis sets up the Reliability Evaluation Model of safety and stability control device based on Markovian state space is as follows:

1, the crash rate of safety and stability control device is step 2) in the failure of apparatus rate λ that asks for;

2, the fault of On-line self-diagnosis and supervision is set to detect coefficient as C ₁, NF malfunction number of times account for do not detect malfunction and tripping number of times and number percent be C ₂, then NF hidden failure malfunction rate C ₃c is divided with NF hidden failure tripping rate ₄be not:

C ₃＝C ₂(1-C ₁)λ

C ₄＝(1-C ₂)(1-C ₁)λ

The recessive malfunction fault of device and recessive tripping fault can be found when prophylactic repair to repair, if prophylactic repair rate is μ ₂;

3, the failure rate that safety and stability control device can check out is C ₅=C ₁λ, detecting fault restoration rate is μ ₁;

4, the rate of breakdown of the recessive tripping fault of triggering secure stabilization control device is λ _s, the rate of breakdown of the recessive malfunction fault of triggering secure stabilization control device is λ _ex;

5, can mutually shift between recessive malfunction state and recessive tripping state, recessive malfunction hidden danger is C to the rate of transform of recessive tripping hidden danger ₆, recessive tripping hidden danger is C to the rate of transform of recessive malfunction hidden danger ₇;

6, do not consider communication port problem, do not consider the locking failure problems of device, plant failure can return to serviceable condition after repairing, and above-mentioned failure rate and repair rate are constant;

7, can be repaired immediately after supposing protected element fault;

302) in step 301) on the basis of precondition determined, set up the Markovian state space diagram of safety and stability control device, obtain the Reliability Evaluation Model of safety and stability control device.The Markovian state space diagram of the safety and stability control device set up as shown in Figure 3.

Step 4 in Fig. 1: the history run according to safety and stability control device is added up, obtain related data, computationally secure stabilization control device be in completely normal, recessive malfunction, recessive tripping and complete failure 4 kinds of different running statuses time probable value, its detailed process is:

401) according to step 302) in safety and stability control device Markovian state space diagram set up such as formula the state space equation shown in (3):

PT＝0

$\underset{i=1}{\overset{4}{\mathrm{\Σ}}}{p}_i=1---\left(3\right)$

Wherein, P=[p ₁, p ₂, p ₃, p ₄] be the plateau probability of each state, p ₁probability during corresponding normal operating condition completely, p ₂probability during corresponding recessive malfunction state, p ₃probability during corresponding recessive tripping state, p ₄probability during corresponding intrument complete failure; T is state transition probability density matrix, and its expression formula is:

$T=\left[\begin{array}{cccc}-(C_3+C_4+C_5)& C_3& C_4& C_5\\ {\mathrm{\μ}}_2& -({\mathrm{\μ}}_2+C_6+{\mathrm{\λ}}_{\mathrm{ex}})& C_6& {\mathrm{\λ}}_{\mathrm{ex}}\\ {\mathrm{\μ}}_2& C_7& -({\mathrm{\μ}}_2+C_7+{\mathrm{\λ}}_s)& {\mathrm{\λ}}_s\\ {\mathrm{\μ}}_1& 0& 0& -{\mathrm{\μ}}_1\end{array}\right]---\left(4\right)$

402) according to the history run of safety and stability control device, statistics obtaining step 302) in correlation parameter in state space graph and state transition probability density matrix T, in conjunction with the failure of apparatus rate λ tried to achieve, according to formula (3), formula (4) computationally secure stabilization control device be in completely normal, recessive malfunction, recessive tripping and complete failure 4 kinds of different running statuses time probable value.

Although the present invention with preferred embodiment openly as above, embodiment is not of the present invention for limiting.Without departing from the spirit and scope of the invention, any equivalence change done or retouching, belong to the protection domain of the present invention equally.Therefore the content that protection scope of the present invention should define with the claim of the application is standard.

Claims (4)

1. consider to it is characterized in that the safety and stability control device fail-safe analysis method that multimode runs, comprise the following steps:

1) hardware system structure of safety and stability control device is analyzed;

2) set up the fault tree models of safety and stability control device based on Fault Tree, obtain the crash rate λ of safety and stability control device;

3) consider 4 kinds of running statuses of safety and stability control device: normal operating condition, recessive malfunction state, recessive tripping state and total failure mode completely, set up the Reliability Evaluation Model of safety and stability control device based on Markovian state space;

4) add up according to the history run of safety and stability control device, obtain related data, computationally secure stabilization control device be in completely normal, recessive malfunction, recessive tripping and complete failure 4 kinds of different running statuses time probable value.

2. the safety and stability control device fail-safe analysis method run of consideration multimode according to claim 1, is characterized in that, described step 2) detailed process be:

201) based on step 1) in the analysis result of hardware system structure, set up the fault tree models of safety and stability control device;

202) safety and stability control device crash rate λ is asked for:

According to the reliability of electronic equipment Prediction Model of U.S. Military handbook " MIL-HDBK-217F ", the crash rate λ of each electronic devices and components in each steady control module of computationally secure stabilization control device _i, then the crash rate λ of each steady control module is asked by formula (1) _sCM:

${\mathrm{\λ}}_{\mathrm{SCM}}=\underset{i=1}{\overset{m}{\mathrm{\Σ}}}{N}_i{\mathrm{\λ}}_i---\left(1\right)$

Wherein, λ _sCMfor the crash rate of single steady control module, λ _ibe the crash rate of i-th kind of components and parts, m is components and parts species number in steady control module, N _iit is total number of i-th kind of components and parts;

Give each steady control module weight according to steady control module for the importance of device, ask for the crash rate λ of device according to main control unit, I/O unit and the communication unit logical relation respectively formed between steady control module:

$\mathrm{\λ}={\mathrm{\λ}}_{\mathrm{main}}+{\mathrm{\λ}}_{\mathrm{IO}}+{\mathrm{\λ}}_{\mathrm{CU}}=\underset{j1=1}{\overset{J1}{\mathrm{\Σ}}}{\mathrm{\ξ}}_{j1}{\mathrm{\λ}}_{\mathrm{SCM}}^{j1}+\underset{j2=1}{\overset{J2}{\mathrm{\Σ}}}{\mathrm{\ξ}}_{j2}{\mathrm{\λ}}_{\mathrm{CSM}}^{j2}+\underset{j3=1}{\overset{J3}{\mathrm{\Σ}}}{\mathrm{\ξ}}_{j3}{\mathrm{\λ}}_{\mathrm{SCM}}^{j3}---\left(2\right)$

Wherein: λ is the crash rate of device; λ _main, λ _iOand λ _cUbe respectively the crash rate of main control unit, I/O unit and communication unit; ξ _j1for jth 1 main control unit surely controls module weight corresponding in safety and stability control device, ξ _j2for jth 2 I/O unit surely control module weight corresponding in safety and stability control device, ξ _j3for jth 3 communication units surely control module weight corresponding in safety and stability control device; for jth 1 main control unit surely controls the crash rate of module, for jth 2 I/O unit surely control the crash rate of module, for jth 3 communication units surely control the crash rate of module; J1, J2 and J3 are respectively the steady control module sum of main control unit, I/O unit and communication unit.

3. the safety and stability control device fail-safe analysis method of consideration multimode operation according to claim 1, it is characterized in that, described step 3) in set up the Reliability Evaluation Model of safety and stability control device based on Markovian state space detailed process be:

301) determine that the precondition that analysis sets up the Reliability Evaluation Model of safety and stability control device based on Markovian state space is as follows:

1, the crash rate of safety and stability control device is step 2) in the failure of apparatus rate λ that asks for;

2, the fault of On-line self-diagnosis and supervision is set to detect coefficient as C ₁, NF malfunction number of times account for do not detect malfunction and tripping number of times and number percent be C ₂, then NF hidden failure malfunction rate C ₃c is divided with NF hidden failure tripping rate ₄be not:

C ₃＝C ₂(1-C ₁)λ

C ₄＝(1-C ₂)(1-C ₁)λ

The recessive malfunction fault of device and recessive tripping fault can be found when prophylactic repair to repair, if prophylactic repair rate is μ ₂;

3, the failure rate that safety and stability control device can check out is C ₅=C ₁λ, detecting fault restoration rate is μ ₁;

4, the rate of breakdown of the recessive tripping fault of triggering secure stabilization control device is λ _s, the rate of breakdown of the recessive malfunction fault of triggering secure stabilization control device is λ _ex;

5, can mutually shift between recessive malfunction state and recessive tripping state, recessive malfunction hidden danger is C to the rate of transform of recessive tripping hidden danger ₆, recessive tripping hidden danger is C to the rate of transform of recessive malfunction hidden danger ₇;

6, do not consider communication port problem, do not consider the locking failure problems of device, plant failure can return to serviceable condition after repairing, and above-mentioned failure rate and repair rate are constant;

7, can be repaired immediately after supposing protected element fault;

302) in step 301) on the basis of precondition determined, set up the Markovian state space diagram of safety and stability control device, obtain the Reliability Evaluation Model of safety and stability control device.

4. the safety and stability control device fail-safe analysis method of consideration multimode operation according to claim 3, it is characterized in that, described step 4) in, computationally secure stabilization control device be in completely normal, recessive tripping, recessive malfunction and complete failure 4 kinds of different running statuses time the detailed process of probable value be:

401) according to step 302) in safety and stability control device Markovian state space diagram set up such as formula the state space equation shown in (3):

PT＝0

$\underset{i=1}{\overset{4}{\mathrm{\Σ}}}{p}_i=1---\left(3\right)$

Wherein, P=[p ₁, p ₂, p ₃, p ₄] be the plateau probability of each state, p ₁probability during corresponding normal operating condition completely, p ₂probability during corresponding recessive malfunction state, p ₃probability during corresponding recessive tripping state, p ₄probability during corresponding intrument complete failure; T is state transition probability density matrix, and its expression formula is:

$T=\left[\begin{array}{cccc}-(C_3+C_4+C_5)& C_3& C_4& C_5\\ {\mathrm{\μ}}_2& -({\mathrm{\μ}}_2+C_6+{\mathrm{\λ}}_{\mathrm{ex}})& C_6& {\mathrm{\λ}}_{\mathrm{ex}}\\ {\mathrm{\μ}}_2& C_7& -({\mathrm{\μ}}_2+C_7+{\mathrm{\λ}}_s)& {\mathrm{\λ}}_s\\ {\mathrm{\μ}}_1& 0& 0& -{\mathrm{\μ}}_1\end{array}\right]---\left(4\right)$

402) according to the history run of safety and stability control device, statistics obtaining step 302) in correlation parameter in state space graph and state transition probability density matrix T, in conjunction with the failure of apparatus rate λ tried to achieve, according to formula (3), formula (4) computationally secure stabilization control device be in completely normal, recessive malfunction, recessive tripping and complete failure 4 kinds of different running statuses time probable value.