CN103001235A - Method for evaluating risks of MOV (metal oxide varistor) of series capacitive compensator - Google Patents

Abstract

The invention discloses a method for evaluating risks of an MOV (metal oxide varistor) of a series capacitive compensator. The method includes the steps of (1) acquiring parameters including preventive trial data and electric monitoring data of the MOV of the series capacitive compensator; (2) establishing characteristic quantity including failure modes and probability of risk occurrence, establishing an incidence matrix about the probability of risk occurrence and failure modes, and establishing the risk evaluation for the MOV of the series capacitive compensator. Based on preventive trials, unbalanced current and historical data, the method can evaluate series compensation risks, simultaneously breaks through design and manufacture problem of international high-energy high-capacity MOVs, and improves operation reliability of the series compensation system.

Description

A kind of compensator with series capaci tance MOV methods of risk assessment

Technical field

The present invention relates to the series capacitor compensation technology field of ac transmission, particularly a kind of compensator with series capaci tance MOV methods of risk assessment.

Background technology

Along with the enhancing to energy demand of the continuous growth of national economy and entire society, the new power transmission line corridor of planning that causes in short supply of land resource brings great difficulty simultaneously, and the utilance that therefore improves existing power transmission line corridor solves present difficulty important effect.Its method has HVDC Light, improves the line voltage distribution grade, feeds back electricity build, compensator with series capaci tance (string mend) etc. with tower more, yet HVDC Light, improve the line voltage distribution grade, feed back electric construction with tower more and can concentrate to large load center and send electricity, but need to transform electric power line pole tower type or insulation coordination level, and compensator with series capaci tance only need install the utilance that power transmission line corridor can be improved in string benefit station additional, therefore than other technologies, compensator with series capaci tance has obvious advantage.

The main purpose of series capacitance compensator be reduce transmission line from the sending end to the receiving end between total equivalent series resistance, its Main Function has: 1) change the impedance of system, 2) improve transmittability, trend is controlled, reduce network loss, 3) the control node voltage improves reactive balance, improves static voltage stability, 4) improve the dynamic behaviour of electric power system, damping system low frequency and sub-synchronous oscillation, 5) improve transient stability, 6) seal in inductance and reduce short circuit current.When the string complement system breaks down, be connected in parallel on the MOV at capacitor two ends as the first heavily protection, its quick acting is with capacitor short-circuit, and with the residual voltage level of its limiting voltage at lightning arrester, the while seals in system to reactor to suppress the first peak value of short circuit current.During the system failure, short circuit current mainly flows through from MOV, and it must absorb huge short circuit energy within the quite short time, cause the self-heating temperature to raise.The accident that occurs at present has: 1) 15: 16: 54 on the 3rd March in 2008, and 500kV horse hundred line B phase transient faults, behind about 57.50ms, protection action tripping circuit B phase.About 1049ms switch overlaps behind the failure removal, and circuit resumes operation, and this maximum fault current appears at fault and begins rear 31.88ms, current peak 8251A.Overlap behind the 241ms mutually fault again of B, behind about 66.25ms, tripping circuit three-phase is moved in protection; this maximum fault current appears at fault and begins rear 31.25ms; current peak 8103A, this moment horse hundred line strings mend B phase MOV the second time during fault blast damage, string is mended Permanent lockout.2) 15: 38 on the 10th February in 2010, A, B phase-to phase fault (being called for short for the first time line fault) occur in sieve's 500kV hundred I lines, route protection correct operation excision fault, and reclosing is failure to actuate, and sieve's 500kV hundred I line strings are mended the three-phase bypass, heavily do not throw.Sieve's 500kV hundred I specific electric loads are P:143.73MW before tripping, voltage 543.47kV, and electric current 259.28A, through sieve's 500kV hundred I lines and string benefit interval are correlated with secondary device inspection without after unusual, 16: 37 circuits and the benefit priority of going here and there are recovered normal and are moved; 17: 09, B, C phase-to phase fault (being called for short for the second time line fault) occured in sieve's 500kV hundred I lines, route protection correct operation excision fault, and fault while sieve's 500kV hundred I line strings are mended B phase MOV fault and are burst damage, and string is mended Permanent lockout.Sieve's 500kV hundred I lines P:59.88MW that loaded at that time before the fault trip for the second time, voltage 539.40kV, electric current 92.29A.3) 2010 03 month 21: 25: 18 on the 27th, the alternate earth fault three-phase tripping operation of 500kV horse hundred line B, C.Horse hundred specific electric load P:161.49MW at that time, voltage 536kV, electric current 203.61A.500kV horse hundred line strings are mended the three-phase bypass, heavily do not throw, and the inspection discovery B that goes up on the stage goes here and there mutually and mends a MOV pressure relief device action, and MOV thoroughly damages, string benefit Permanent lockout.Therefore the safe and stable operation of MOV is having a strong impact on and is going here and there the reliability of complement system.

The state analysis of mending MOV for string has: based on the insulation resistance of preventive trial, the reference voltage under the 1mA, the Leakage Current under 0.75 reference voltage; Mend the unsymmetrical current of control protection based on string; Based on historical datas such as device manufacturing process level, familial defective, fault case, defect analysiss; The large capacity MOV's of high energy manufactures and designs the core secrecy technology that still belongs to each company in the world; Existing method is assessed preventive trial data, unsymmetrical current, historical data, manufacturing process philosophy the MOV risk assessment by different professionals simultaneously.Therefore based on existing monitoring means, carry out systematic string and mend the MOV methods of risk assessment, to improving the string reliable rate of complement system and ensureing that the continual and steady energy resource supply of power transmission line corridor has great significance, and has promoted the sustainable growth of national economy.

Summary of the invention

The object of the invention is to overcome existing the string based on preventive trial, unsymmetrical current, historical summary respectively and mend the one-sidedness that risk assessment exists, break through simultaneously the in the world barrier problem that manufactures and designs of the large capacity MOV of high energy, improve the reliable rate of string complement system, a kind of compensator with series capaci tance MOV methods of risk assessment is provided.

For realizing above purpose, the present invention has taked following technical scheme: the methods of risk assessment of a kind of compensator with series capaci tance MOV comprises the steps:

S1, parameter acquiring: the preventive trial data of compensator with series capaci tance MOV, the live monitoring data of compensator with series capaci tance MOV;

The preventive trial data of described compensator with series capaci tance MOV comprise insulation resistance, absorptance and polarization index, DC reference voltage under the 1mA, DC reference voltage under the 4mA, leakage current under 0.75 times of DC reference voltage, the power frequency reference voltage under the 1mA; Power frequency reference voltage under the 4mA, current in resistance property;

The live monitoring data of described compensator with series capaci tance MOV comprise the running current of compensator with series capaci tance MOV, the unsymmetrical current of compensator with series capaci tance MOV, the working voltage of compensator with series capaci tance MOV, the force value of compensator with series capaci tance MOV, the body temperature of compensator with series capaci tance MOV, the ambient temperature of compensator with series capaci tance MOV, the surface filth of compensator with series capaci tance MOV;

S2, according to the parameter acquiring of compensator with series capaci tance MOV methods of risk assessment, set up the characteristic quantity of compensator with series capaci tance MOV methods of risk assessment, it comprises the coding of preventive trial data and live monitoring data, feature value, pilot project;

The feature value of compensator with series capaci tance MOV methods of risk assessment is formed vectorial D, and its size is 1 * N, and N is the characteristic quantity sum of compensator with series capaci tance MOV methods of risk assessment,

First of vector D classifies the value of pilot project insulation resistance as, corresponding coding Y ₁Second classifies pilot project absorptance or polarization index value as, corresponding coding Y ₂The 3rd classifies the DC reference voltage value under the pilot project 1mA as, corresponding coding Y ₃The 4th classifies the DC reference voltage value under the pilot project 4mA as, corresponding coding Y ₄The 5th classifies leakage current values under 0.75 times of DC reference voltage of pilot project as, corresponding coding Y ₅The 6th classifies the power frequency reference voltage level under the pilot project 1mA as, corresponding coding Y ₆The 7th classifies the power frequency reference voltage level under the pilot project 4mA as, corresponding coding Y ₇The 8th classifies pilot project current in resistance property value as, corresponding coding Y ₈The 9th classifies the running current value of pilot project compensator with series capaci tance MOV as, corresponding coding Y ₉The tenth classifies the unsymmetrical current value of pilot project compensator with series capaci tance MOV as, corresponding coding Y ₁₀The 11 classifies the working voltage value of pilot project compensator with series capaci tance MOV as, corresponding coding Y ₁₁The 12 classifies the force value of pilot project compensator with series capaci tance MOV as, corresponding coding Y ₁₂The 13 classifies the body temperature value of pilot project compensator with series capaci tance MOV as, corresponding coding Y ₁₃The 14 classifies the ambient temperature value of pilot project compensator with series capaci tance MOV as, corresponding coding Y ₁₄The 15 classifies the surface filth value of pilot project compensator with series capaci tance MOV as, corresponding coding Y ₁₅

The fault mode of S3, compensator with series capaci tance MOV methods of risk assessment

System's composition function according to compensator with series capaci tance MOV, set up for MOV valve block unit, aluminum annular-shaped conductive cushion block unit, the coolant unit, the epoxy resins insulation cartridge unit, the fault mode of composite silicone rubber material umbrella cover unit, the fault mode of each unit comprises function code, fault mode code, failure-description simultaneously.

The fault mode of described MOV valve block unit comprises function code A1, and the fault mode code is A1.1, and failure-description is the aging of MOV valve block or makes moist that the fault mode code is A1.2, and failure-description is the puncture of MOV valve block;

The fault mode of described aluminum annular-shaped conductive cushion block unit comprises function code A2, and the fault mode code is A2.1, and failure-description is the unit loose contact of aluminum annular-shaped conductive cushion block, and the fault mode code is A1.2, and failure-description is making moist of aluminum annular-shaped conductive cushion block unit;

The fault mode of described coolant unit comprises function code A3, and the fault mode code is A3.1, and failure-description is the coolant units age, and the fault mode code is A3.2, and failure-description is that the coolant cell temperature is too high;

The fault mode of described epoxy resins insulation cartridge unit comprises function code A4, the fault mode code is A4.1, failure-description is the aging of epoxy resins insulation cartridge unit or makes moist that the fault mode code is A4.2, and failure-description is the puncture of epoxy resins insulation cartridge unit;

The fault mode of described composite silicone rubber material umbrella cover unit comprises function code A5, the fault mode code is A5.1, failure-description is the aging of composite silicone rubber material umbrella cover unit or makes moist that the fault mode code is A5.2, and failure-description is the puncture of composite silicone rubber material umbrella cover unit; The fault mode code is A5.3, and failure-description is the filth of composite silicone rubber material umbrella cover unit;

S4, according to the characteristic quantity of compensator with series capaci tance MOV methods of risk assessment, set up the risk probability of happening of compensator with series capaci tance MOV methods of risk assessment, the demand value of each characteristic quantity is divided into higher limit and lower limit, adopt respectively the calculating formula of risk probability of happening suc as formula (1) and (2), and formation risk probability of happening vector K, its size is 1 * N, and N is the characteristic quantity sum of compensator with series capaci tance MOV methods of risk assessment;

$P\left(Y_i\right)=\frac{Y_i^2}{Y_i^2+a^2}---\left(1\right)$

$P\left(Y_i\right)=\left\{\begin{array}{cc}0.5-0.5\sin \frac{\mathrm{\π}}{2b}(Y_i-b)& Y_i\≤2b\\ 0& Y_i>2b\end{array}\right.---\left(2\right)$

A represents that demand value is higher limit in the formula, and b represents that demand value is lower limit, Y _iThe characteristic quantity of expression compensator with series capaci tance MOV methods of risk assessment, span Y ₁: Y ₁₅

The demand value of described each characteristic quantity is divided into higher limit and lower limit comprises that the insulation resistance demand value is that 500M, absorptance and polarization index are respectively 1.3 and 1.5, DC reference voltage under the 1mA is 120kV, DC reference voltage under the 4mA is 45kV, 0.75 doubly leakage current is 50 μ A under the DC reference voltage, the power frequency reference voltage 30kV under the 1mA; Power frequency reference voltage under the 4mA is 145kV, current in resistance property is 15 μ A, the running current of compensator with series capaci tance MOV is 35 μ A, the unsymmetrical current 500 μ A of compensator with series capaci tance MOV, the working voltage of compensator with series capaci tance MOV is 550kV, the force value of compensator with series capaci tance MOV is 1.2MPa, the body temperature of compensator with series capaci tance MOV is 150 ℃, the ambient temperature of compensator with series capaci tance MOV is 55 ℃, and the surface filth of compensator with series capaci tance MOV is 0.25mg/cm ²

S5, the risk probability of happening of setting up according to the characteristic quantity of compensator with series capaci tance MOV methods of risk assessment, set up incidence matrices M in conjunction with the relation of characteristic quantity and fault mode, its size is B * N, B represents total classification size of fault mode, the total quantity of N representation feature amount, the element M of its incidence matrices M _IjComputational methods suc as formula (3);

$M_{\mathrm{ij}}=\frac{\underset{j}{\min }\underset{i}{\min }|D_j-D_i|+\mathrm{\ξ}\underset{j}{\max }\underset{i}{\max }|D_j-D_i|}{|D_j-D_i|+\mathrm{\ξ}\underset{j}{\max }\underset{i}{\max }|D_j-D_i|}---\left(3\right)$

D in the formula _jAnd D _iRepresent respectively characteristic of correspondence amount under j and the i kind fault mode, ξ is resolution ratio, and span is (0,1);

S6, the risk assessment of setting up compensator with series capaci tance MOV methods of risk assessment

Characteristic quantity, risk probability of happening and fault mode incidence matrices according to compensator with series capaci tance MOV methods of risk assessment, foundation is for MOV valve block unit, aluminum annular-shaped conductive cushion block unit, the coolant unit, the epoxy resins insulation cartridge unit, the risk assessment of composite silicone rubber material umbrella cover unit, its computational methods are suc as formula (4);

$A_j=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{M}_{j\×i}\·D_i*w\left(i\right)---\left(4\right)$

A in the formula _jBe j kind fault mode, N is the total quantity of characteristic quantity, and i characteristic quantity of w (i) expression is for the weight of j kind fault mode, and span is (0,1);

Utilize formula (4) to calculate MOV valve block unit, aluminum annular-shaped conductive cushion block unit, coolant unit, epoxy resins insulation cartridge unit, the risk assessment value of composite silicone rubber material umbrella cover unit is got the maximum of each unit risk assessment value again as the value-at-risk of compensator with series capaci tance MOV.

The present invention compared with prior art, have following advantage: the string that carries out system based on preventive trial, unsymmetrical current, historical summary is mended risk assessment, break through simultaneously the problem that manufactures and designs of the large capacity MOV of high energy in the world, improve the reliable rate of string complement system.

Description of drawings

Fig. 1 is system flow schematic diagram of the present invention;

Fig. 2 is the parameter acquiring schematic diagram of compensator with series capaci tance MOV methods of risk assessment;

Fig. 3 is the systemic-function schematic diagram of compensator with series capaci tance MOV.

Embodiment

Below in conjunction with the drawings and specific embodiments content of the present invention is described in further details.

Embodiment: see also shown in Figure 1ly, for further specifying characteristics of the present invention, present embodiment is calculated as follows by concrete example:

The parameter acquiring of compensator with series capaci tance MOV methods of risk assessment comprises the insulation resistance meter of measuring insulation resistance, absorptance and polarization index; Measure the DC reference voltage under the 1mA, the high voltage direct current generator of leakage current under the DC reference voltage under the 4mA, 0.75 times of DC reference voltage; Measure the power frequency reference voltage under the 1mA; Power frequency reference voltage under the 4mA, the power frequency generator of current in resistance property; Measure the running current of compensator with series capaci tance MOV, the current transformer of the unsymmetrical current of compensator with series capaci tance MOV; Measure the voltage transformer of the working voltage of compensator with series capaci tance MOV, measure the Pressure gauge of the force value of compensator with series capaci tance MOV, measure the body temperature of compensator with series capaci tance MOV, the thermometer of the ambient temperature of compensator with series capaci tance MOV, measure compensator with series capaci tance MOV surface filth measuring instrument, be the commercially available prod.The insulation resistance meter of measuring insulation resistance, absorptance and polarization index adopts the electric numerical megger ST2000 of Su Te; Measure the DC reference voltage under the 1mA, the high voltage direct current generator of leakage current adopts the model BPXZ-50/50/25 of Wuhan City Huatian Electric Power Automation Co., Ltd. under the DC reference voltage under the 4mA, 0.75 times of DC reference voltage; Measure the power frequency reference voltage under the 1mA; Power frequency reference voltage under the 4mA, the power frequency generator of current in resistance property adopt the YD intelligence power frequency withstand test device of electric magnificent source, south, Wuhan Electric Applicance Co., Ltd; Measure the running current of compensator with series capaci tance MOV, the current transformer of the unsymmetrical current of compensator with series capaci tance MOV adopts the model LVQBT-500 of Henan high-voltage switch gear Co., Ltd of Ping Gao Toshiba; The voltage transformer of measuring the working voltage of compensator with series capaci tance MOV adopts the model 26-1E-7980111 of Henan high-voltage switch gear Co., Ltd of Ping Gao Toshiba, the Pressure gauge of measuring the force value of compensator with series capaci tance MOV adopts the HQ-SY-C precision digital Pressure gauge of red flag instrument, measure the body temperature of compensator with series capaci tance MOV, the thermometer of the ambient temperature of compensator with series capaci tance MOV adopts the DSC-DTSnK-XB of Dien instrument, the measuring instrument of measuring the surface filth of compensator with series capaci tance MOV adopt electric magnificent source, south, Wuhan Electric Applicance Co., Ltd NDYMD digital direct-reading type intelligence salt density test instrument.Method step is as follows:

1, the parameter acquiring of compensator with series capaci tance MOV methods of risk assessment: the numerical megger ST2000 electric by Su Te measures insulation resistance, absorptance and polarization index; By the DC reference voltage under the model BPXZ-50/50/25 of Wuhan City Huatian Electric Power Automation Co., Ltd. measurement 1mA, the DC reference voltage under the 4mA, leakage current under 0.75 times of DC reference voltage; By the power frequency reference voltage under the YD intelligence power frequency withstand test measurement device 1mA, the power frequency reference voltage under the 4mA, current in resistance property; Model LVQBT-500 by high-voltage switch gear Co., Ltd of Henan Ping Gao Toshiba measures the running current of compensator with series capaci tance MOV, the unsymmetrical current of compensator with series capaci tance MOV; Measure the working voltage of compensator with series capaci tance MOV by the model 26-1E-7980111 of high-voltage switch gear Co., Ltd of Henan Ping Gao Toshiba; The force value of HQ-SY-C precision digital gauge measurement compensator with series capaci tance MOV by the red flag instrument; DSC-DTSnK-XB by the Dien instrument measures the body temperature of compensator with series capaci tance MOV, the ambient temperature of compensator with series capaci tance MOV; By electric magnificent source, Wuhan south Electric Applicance Co., Ltd NDYMD digital direct-reading type intelligence salt density test instrument measure the surface filth of compensator with series capaci tance MOV.Its measurement result such as table 1;

Table 1: the parameter of compensator with series capaci tance MOV methods of risk assessment

2, compensator with series capaci tance MOV methods of risk assessment

1) characteristic quantity of compensator with series capaci tance MOV methods of risk assessment: according to the parameter acquiring of compensator with series capaci tance MOV methods of risk assessment, set up the characteristic quantity of compensator with series capaci tance MOV methods of risk assessment, and the vectorial D of the feature value that forms compensator with series capaci tance MOV methods of risk assessment, its size is 1 * 15, and wherein the characteristic quantity of compensator with series capaci tance MOV methods of risk assessment adds up to 15;

$D=\left[\begin{array}{c}15.6\\ 1.4\\ .\\ .\\ .\\ 0.18\end{array}\right]$

2) fault mode of compensator with series capaci tance MOV methods of risk assessment

System's composition function according to compensator with series capaci tance MOV, set up for MOV valve block unit, aluminum annular-shaped conductive cushion block unit, the coolant unit, the epoxy resins insulation cartridge unit, the fault mode of composite silicone rubber material umbrella cover unit, the fault mode of each unit comprises that function code, fault mode code, failure-description form its fault mode result such as table 2 simultaneously;

Function code	The fault mode code	Failure-description
			A1	A1.1	MOV valve block aging or make moist
A1	A1.2	The puncture of MOV valve block
			...	...	...
A5	A5.3	The filth of composite silicone rubber material umbrella cover unit

3) the risk probability of happening of compensator with series capaci tance MOV methods of risk assessment

Characteristic quantity according to compensator with series capaci tance MOV methods of risk assessment, set up the risk probability of happening of compensator with series capaci tance MOV methods of risk assessment, therefore the demand value with each characteristic quantity is divided into higher limit and lower limit, adopt respectively the calculating formula of risk probability of happening suc as formula (1) and (2), and forming risk probability of happening vector K, its size is 1 * 15;

$D=\left[\begin{array}{c}0.13\\ 0.014\\ .\\ .\\ .\\ 0.78\end{array}\right]$

4) set up risk probability of happening and the fault mode incidence matrices of compensator with series capaci tance MOV methods of risk assessment

The risk probability of happening of setting up according to the characteristic quantity of compensator with series capaci tance MOV methods of risk assessment, utilize formula (3) to set up incidence matrices M, its size is 15 * 15 (B * N), total classification size of row coefficient 15 expression fault modes, the total quantity of row coefficient 15 representation feature amounts

$M=\left[\begin{array}{cccc}0.31& 0.31& ...& 0\\ 0.29& 0.25& ...& 0\\ .& .& .& .\\ .& .& .& .\\ .& .& .& .\\ 0.11& 0.05& ...& 0.8\end{array}\right]$

5) set up the risk assessment of compensator with series capaci tance MOV methods of risk assessment

Characteristic quantity, risk probability of happening and fault mode incidence matrices according to compensator with series capaci tance MOV methods of risk assessment, utilize formula (4) to set up and carry out MOV valve block unit, aluminum annular-shaped conductive cushion block unit, the coolant unit, the epoxy resins insulation cartridge unit, the risk assessment of composite silicone rubber material umbrella cover unit;

$\left[\begin{array}{c}{A}_1\\ A_2\\ .\\ .\\ .\\ A_{15}\end{array}\right]=\left[\begin{array}{c}0.073\\ 0.039\\ .\\ .\\ .\\ 0.852\end{array}\right]$

Therefore can judge that according to above-mentioned matrix the value-at-risk aging or that make moist of MOV valve block is 0.073, the puncture value-at-risk of MOV valve block is 0.03, the value-at-risk of other fault modes the like, the maximum of each unit risk assessment value is 0.852 value-at-risk as compensator with series capaci tance MOV simultaneously.

Effect analysis: by the analysis of above-mentioned example, can judge the aging of MOV valve block or the value-at-risk of making moist is 0.03 as the puncture value-at-risk of 0.073, MOV valve block, the value-at-risk of compensator with series capaci tance MOV is 0.852 simultaneously.Therefore the method is mended risk assessment based on the string that preventive trial, unsymmetrical current, historical summary carry out system, breaks through simultaneously the problem that manufactures and designs of the large capacity MOV of high energy in the world, and improves the reliable rate of string complement system.

Present embodiment applies to:

1, the risk assessment of 500kV ac transmission compensator with series capaci tance MOV;

2, operation risk analysis, repair based on condition of component, the aid decision of 110kV and above ac transmission compensator with series capaci tance MOV;

Above-listed detailed description is that this embodiment limits claim of the present invention for the specifying of possible embodiments of the present invention, and the equivalence that all the present invention of disengaging do is implemented or change, all should be contained in the claim of this case.

Claims (1)

1. a compensator with series capaci tance MOV methods of risk assessment is characterized in that, comprises the steps:

S1, parameter acquiring: the preventive trial data of compensator with series capaci tance MOV, the live monitoring data of compensator with series capaci tance MOV;

S2, according to the parameter acquiring of compensator with series capaci tance MOV methods of risk assessment, set up the characteristic quantity of compensator with series capaci tance MOV methods of risk assessment, it comprises the coding of preventive trial data and live monitoring data, feature value, pilot project; The feature value of compensator with series capaci tance MOV methods of risk assessment is formed vectorial D, and its size is 1 * N, and N is the characteristic quantity sum of compensator with series capaci tance MOV methods of risk assessment;

The fault mode of S3, compensator with series capaci tance MOV methods of risk assessment

System's composition function according to compensator with series capaci tance MOV, set up for MOV valve block unit, aluminum annular-shaped conductive cushion block unit, the coolant unit, the epoxy resins insulation cartridge unit, the fault mode of composite silicone rubber material umbrella cover unit, the fault mode of each unit comprises function code, fault mode code, failure-description simultaneously;

S4, according to the characteristic quantity of compensator with series capaci tance MOV methods of risk assessment, set up the risk probability of happening of compensator with series capaci tance MOV methods of risk assessment, the demand value of each characteristic quantity is divided into higher limit and lower limit, adopt respectively the calculating formula of risk probability of happening suc as formula (1) and (2), and formation risk probability of happening vector K, its size is 1 * N, and N is the characteristic quantity sum of compensator with series capaci tance MOV methods of risk assessment;

$P\left(Y_i\right)=\frac{Y_i^2}{Y_i^2+a^2}---\left(1\right)$

$P\left(Y_i\right)=\left\{\begin{array}{cc}0.5-0.5\sin \frac{\mathrm{\π}}{2b}(Y_i-b)& Y_i\≤2b\\ 0& Y_i>2b\end{array}\right.---\left(2\right)$

A represents that demand value is higher limit in the formula, and b represents that demand value is lower limit, Y _iThe characteristic quantity of expression compensator with series capaci tance MOV methods of risk assessment, span Y ₁: Y ₁₅

S5, the risk probability of happening of setting up according to the characteristic quantity of compensator with series capaci tance MOV methods of risk assessment, set up incidence matrices M in conjunction with the relation of characteristic quantity and fault mode, its size is B * N, and B represents total classification size of fault mode, the total quantity of N representation feature amount.The element M of its incidence matrices M _IjComputational methods suc as formula (3);

$M_{\mathrm{ij}}=\frac{\underset{j}{\min }\underset{i}{\min }|D_j-D_i|+\mathrm{\ξ}\underset{j}{\max }\underset{i}{\max }|D_j-D_i|}{|D_j-D_i|+\mathrm{\ξ}\underset{j}{\max }\underset{i}{\max }|D_j-D_i|}---\left(3\right)$

D in the formula _jAnd D _iRepresent respectively characteristic of correspondence amount under j and the i kind fault mode, ξ is resolution ratio, and span is (0,1);

S25, the risk assessment of setting up compensator with series capaci tance MOV methods of risk assessment

Characteristic quantity, risk probability of happening and fault mode incidence matrices according to compensator with series capaci tance MOV methods of risk assessment, foundation is for MOV valve block unit, aluminum annular-shaped conductive cushion block unit, the coolant unit, the epoxy resins insulation cartridge unit, the risk assessment of composite silicone rubber material umbrella cover unit, its computational methods are suc as formula (4);

$A_j=\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{M}_{j\×i}\·D_i*w\left(i\right)---\left(4\right)$

A in the formula _jBe j kind fault mode, N is the total quantity of characteristic quantity, and i characteristic quantity of w (i) expression is for the weight of j kind fault mode, and span is (0,1);

Utilize formula (4) to calculate MOV valve block unit, aluminum annular-shaped conductive cushion block unit, coolant unit, epoxy resins insulation cartridge unit, the risk assessment value of composite silicone rubber material umbrella cover unit is got the maximum of each unit risk assessment value again as the value-at-risk of compensator with series capaci tance MOV.

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