CN103267912B - A kind of direct current transportation wall bushing risk evaluating system and methods of risk assessment - Google Patents

Abstract

The invention discloses a risk assessment system for DC transmission wall bushings, which includes: preventive test instruments, online monitoring devices, mobile devices, risk assessment centers and communication devices; and at the same time discloses a risk assessment method based on the above system , the method includes the following steps: (1) extracting the characteristic quantity of the risk assessment of the DC transmission wall bushing; (2) extracting the characteristic quantity of the risk assessment of the DC transmission wall bushing; (3) establishing the risk assessment of the DC transmission wall bushing (4) Establish the correlation matrix between the risk occurrence probability and the failure mode of the DC transmission wall bushing; (5) Establish the risk evaluation of the risk assessment method for the DC transmission wall bushing. The present invention carries out the risk assessment of the DC transmission wall bushing based on the preventive test, online monitoring data, and inspection data, and at the same time breaks through the current risk assessment only for preventive tests or online monitoring data or manual inspection data, and improves the DC system. operational reliability.

Description

A risk assessment system and risk assessment method for DC transmission wall bushings

technical field

The invention relates to the technical field of DC system maintenance, in particular to a risk assessment system for DC transmission wall bushings and a risk assessment method using the risk assessment system.

Background technique

Due to the current problems of economic development and uneven energy distribution in China, in order to realize the large-scale transfer and rational utilization of energy, a high-voltage direct current transmission network with ±500kV and ±800kV as the backbone network has been developed in China. Compared with traditional AC transmission technology, its main advantages are:

(1) The line cost is low. Three conductors are used for AC overhead transmission lines, while two conductors are used for DC, which can save a lot of line construction costs.

(2) The annual power loss is small. The resistance loss of the two conductors of the DC overhead transmission line is smaller than that of the AC transmission line; there is no reactive power loss of inductive reactance and capacitive reactance; there is no skin effect, and the cross-section of the conductor is fully utilized. In addition, the space charge effect of the DC overhead line makes its corona loss and radio interference smaller than that of the AC line. Therefore, DC overhead transmission lines are more economical than AC in terms of initial investment in line construction and annual operating costs.

(3) There is no system stability problem, and the asynchronous interconnection of the power grid can be realized, while all synchronous generators in the AC power system maintain synchronous operation. The transmission capacity and distance of DC transmission are not limited by the stability of synchronous operation, and it can also connect two systems with different frequencies to realize non-synchronous networking and improve system stability.

(4) Limit the short-circuit current. Connecting two AC systems causes the short-circuit capacity to increase, and even replace the circuit breaker or add a current limiting device. However, if two AC systems are connected by a DC transmission line, the "constant current control" of the DC system will quickly limit the short-circuit current to near the rated power, and the short-circuit capacity will not increase due to interconnection.

(5) Fast adjustment and reliable operation. The DC transmission can quickly adjust the active power through the thyristor converter, realize the reversal of the power flow, and ensure stable output under normal conditions. In the event of an accident, it can realize the emergency support of the sound system to the faulty system, and can also realize oscillation damping and secondary Inhibition of synchronous oscillations. However, when the AC and DC lines are running in parallel, if the AC line is short-circuited, the DC transmission power can be temporarily increased to reduce the acceleration of the generator rotor and improve the reliability of the system.

(6) There is no capacitor charging current. There is no capacitive current in the steady state of the DC line, and the voltage distribution along the line is stable. When there is no empty or light load, the voltage at the receiving end and the middle of the AC long line will increase abnormally, so there is no need for parallel reactance compensation.

(7) Save line corridors. Considering the same voltage of 500kV, the corridors of a DC and AC transmission line are about 40m and 50m respectively, and the DC transmission efficiency is about twice that of AC.

As an important primary equipment of the DC transmission station, the DC transmission wall bushing realizes the connection between the indoor converter valve equipment and the outdoor DC field equipment. Its own operation risk assessment plays an important role in ensuring the safe and reliable operation of the DC system. significance.

At present, the methods for analyzing the status of DC wall bushings include preventive tests, on-line monitoring and historical data. The preventive test mainly measures the insulation resistance, capacitance and dielectric loss value of the bushing guide rod to the final screen, the insulation resistance, capacitance and dielectric loss value of the final screen to the ground, and the density, pressure and micro-water content of SF ₆ ; online The monitoring is mainly carried out on the capacitance and dielectric loss of the casing end screen, the density, pressure and moisture content of _SF6 ; the historical data is mainly based on historical data such as equipment manufacturing process level, familial defects, fault cases, and defect analysis. However, preventive tests, on-line monitoring and historical data are currently used as independent evaluation systems to assess the health status of DC through-walls, and the risk assessment of DC through-wall bushings based on basic data has not yet been carried out. Therefore, the establishment of a systematic risk assessment system for wall-piercing bushings of DC transmission is of great significance for improving the reliability of DC system operation and ensuring continuous and stable energy supply, and promoting the sustained and stable growth of the national economy.

Contents of the invention

The purpose of the present invention is to overcome the one-sidedness of the existing risk assessment of DC transmission wall bushings based on preventive tests, on-line monitoring and historical data, and at the same time improve the operation reliability of the DC system, and provide a DC transmission wall bushing risk An assessment system and a risk assessment method using the risk assessment system.

To achieve the above object, the present invention has taken the following technical solutions:

A risk assessment system for direct current transmission wall bushings, which includes: a preventive test instrument for conducting preventive tests on direct current transmission wall bushings; an online monitoring device for on-line monitoring of direct current transmission wall bushings ; a mobile device for inspecting the direct current transmission wall bushing; a risk assessment center for analyzing the risks of the direct current transmission wall bushing; and the preventive test data obtained by the preventive test instrument , the online monitoring data obtained by the online monitoring device, the inspection data recorded by the mobile device, and the familial defect data uploaded are all sent to the communication device of the risk assessment center.

The communication device includes a first wireless transceiver module connected to the output end of the preventive test instrument, a second wireless transceiver module connected to the output end of the online monitoring device, a third wireless transceiver module connected to the output end of the mobile device, And a fourth wireless transceiver module connected to the input terminal of the risk assessment center, the first wireless transceiver module, the second wireless transceiver module, and the third wireless transceiver module all perform data transmission with the fourth wireless transceiver module through a wireless network.

The preventive test instrument includes a dielectric loss tester connected between the DC transmission wall bushing and the first wireless transceiver module, a gas component analyzer, a micro-water measuring instrument, a temperature measuring instrument, an air pressure measuring instrument, a DC resistance Measuring instrument, pollution measuring instrument.

The online monitoring device includes an online environmental temperature monitor, an online environmental humidity monitor, an online surface pollution monitor, and an online capacitance and dielectric loss online monitor connected between the DC transmission wall bushing and the second wireless transceiver module. Monitors, SF ₆ density on-line monitors, pressure on-line monitors, micro-moisture content on-line monitors and gas composition on-line monitors.

The first wireless transceiver module, the second wireless transceiver module, the third wireless transceiver module and the fourth wireless transceiver module are all GPRS modules, and the third wireless transceiver module is integrated in the mobile device.

The method for risk assessment using the DC transmission wall bushing risk assessment system includes the following steps:

(1) According to the preventive test data, online monitoring data, and inspection data, extract the feature quantity of the risk assessment of the DC transmission wall bushing, and form the feature quantity value into a vector C, and the vector C is a 1×B-dimensional vector, B is the total number of characteristic quantities for risk assessment of DC transmission wall bushing;

(2) Based on the composition and function of the DC transmission wall bushing, the fault types for the bushing core unit, capacitor core unit, end screen unit, pressure equalizing ring unit, silicone rubber jacket unit, and SF ₆ gas unit are established, The fault type includes a function code, a fault mode code, and a fault description;

(3) According to the characteristic quantity of the risk assessment of the DC transmission wall bushing, the risk occurrence probability of the risk assessment of the DC transmission wall bushing is established; the attention value of each characteristic quantity C _j of the vector C is divided into the upper limit value a _j or The lower limit value b _j adopts the calculation formulas of risk occurrence probability such as formulas (1) and (2) respectively, and forms a risk occurrence probability vector D, which is a 1×B-dimensional vector;

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}^{\mathrm{<span\; class="notranslate">\; 2.3</span>}}}{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}^{\mathrm{<span\; class="notranslate">\; 2.3</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}^{\mathrm{<span\; class="notranslate">\; 2.3</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\mathrm{<span\; class="notranslate">\; 0.46</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 0.46</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}\frac{\mathrm{<span\; class="notranslate">\; 3.11</span>}}{\mathrm{<span\; class="notranslate">\; 1.96</span>}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 0.93</span>}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span>& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}\end{array}\right.<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>$

(4) According to the risk occurrence probability established by the characteristic quantity of the risk assessment of the DC transmission wall bushing, and combining the relationship between the characteristic quantity and the failure mode, the correlation matrix M is established, and its size is E×B, where E represents the total number of failure modes, where The calculation method of the element M _ij of the incidence matrix M is as formula (3):

${\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; |</span>}{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; |</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

In the formula, D _j and D _i represent the components of the j-th and i-th risk occurrence probability vectors respectively, and both i and j are positive integers and 1≤i≤E, 1≤j≤B;

(5) According to the characteristic quantity, risk occurrence probability and correlation matrix of the risk assessment of DC transmission wall bushing, establish the bushing core unit, capacitor core unit, end screen unit, equalizing ring unit, silicone rubber jacket unit, The risk assessment of SF ₆ gas unit, its calculation method is as formula (4);

${\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; B</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; *</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}{\mathrm{<span\; class="notranslate">\; 1.35</span>}<span\; class="notranslate">\; -</span>\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

In the formula, A _i is the risk evaluation component of the i-th failure mode, H _j and H _k represent the entropy of the j-th and k-th feature quantities, and the value range of the entropy is (0, 0.65).

Said B=20, wherein: the characteristic quantity _C1 is the insulation resistance of the preventive test of the guide rod of the DC transmission wall bushing to the final screen; the characteristic quantity _C2 is the preventive test of the guide rod of the DC transmission wall bushing to the final screen The capacitance; the characteristic quantity C3 is the dielectric loss of the preventive test of the guide rod _of the DC transmission wall bushing to the final screen; the characteristic quantity _C4 is the insulation resistance of the preventive test of the final screen of the DC transmission wall bushing to the ground; The characteristic quantity C ₅ is the capacitance of the preventive test of the end screen of the DC transmission wall bushing to the ground; the characteristic quantity C ₆ is the dielectric loss of the end screen of the DC transmission wall bushing to the ground preventive test; the characteristic quantity C ₇ is The DC resistance of the preventive test of the guide rod of the DC transmission wall bushing; the characteristic quantity C ₈ is the pressure of the preventive test of the DC transmission wall bushing; the characteristic quantity C ₉ is the gas composition of the preventive test of the DC transmission wall bushing ; The characteristic quantity C ₁₀ is the pollution value of the preventive test of the DC transmission wall bushing; the characteristic quantity C ₁₁ is the ambient temperature of the online monitoring of the DC transmission wall bushing; the characteristic quantity C ₁₂ is the online monitoring of the DC transmission wall bushing Ambient humidity; characteristic quantity C ₁₃ is the pollution value of online monitoring of DC transmission wall bushing; characteristic quantity C ₁₄ is the capacitance and dielectric loss of the end screen of online monitoring of DC transmission wall bushing; characteristic quantity C ₁₅ is DC transmission The density of SF ₆ gas monitored online by the wall bushing; the characteristic quantity C ₁₆ is the pressure of the DC transmission wall bushing online monitoring; the characteristic quantity C ₁₇ is the micro water monitored by the DC transmission wall bushing online; the characteristic quantity C ₁₈ is the gas composition of the on-line monitoring of the DC transmission wall bushing; the characteristic quantity C ₁₉ is the inspection pressure of the DC transmission wall casing; the characteristic quantity C ₂₀ is the inspection temperature of the DC transmission wall casing.

The upper limit value a _j or the lower limit value b _j corresponding to each characteristic quantity C _j is as follows: b ₁ =10GΩ; b ₂ =-5%; a ₃ =0.8; b ₄ =1GΩ; b ₅ =-5%; b ₆ = -2%; b ₇ = -1%; b ₈ = 8Mpa; a ₉ = 100 μL/L; a ₁₀ = 0.3 mg/cm ² ; a ₁₁ = 80°C; a ₁₂ = 85%; a ₁₃ = 0.3mg/cm ² ; b ₁₄ = -2%; b ₁₅ = 8kg/m ³ ; b ₁₆ = 8MPa; a ₁₇ = 500μL/L; a ₁₈ = 100μL/L; b ₁₉ = _8MPa ; .

Said E=17, wherein: the fault type of the bushing core subunit includes function code A _Ⅰ , the fault mode code is A ₁ , the fault of A ₁ is described as poor contact of the bushing core, and the fault mode code is A 1 . is A ₂ , the fault of A ₂ is described as partial discharge of the bushing core; the fault type of the capacitor core unit includes function code A _Ⅱ , the fault mode code is A ₃ , and the fault of A ₃ is described as _The capacitor core is damp, the fault mode code is A4, the fault of A4 is described as aging of the capacitor core unit, the fault mode code is _A5 , and the fault of _A5 is described as partial discharge of the capacitor core unit _; The failure type of the last screen unit includes function code _AⅢ , the failure mode code is A6, the failure description of A6 is that the last screen unit is _damp , the failure mode code is _A7 , and the _failure description of _A7 is the last The insulation of the screen unit is aging, and the failure mode code is A ₈ , and the failure of A ₈ is described as partial discharge of the last screen unit; the failure type of the voltage equalizing ring unit includes function code A _Ⅳ , and the failure mode code is A ₉ , the said The failure of A ₉ is described as corrosion of the pressure equalizing ring, and the failure mode code is A _10. The failure of A ₁₀ is described as contamination of the pressure equalizing ring unit; the failure type of the silicone rubber jacket unit includes function code A _Ⅴ , failure The mode code is A ₁₁ , the failure description of A ₁₁ is aging of the silicone rubber jacket unit, the failure mode code is A ₁₂ , the failure description of A ₁₂ is contamination of the silicone rubber jacket unit; the failure mode code is A ₁₃ , The failure of A ₁₃ is described as cracking of the silicone rubber jacket unit; the failure type of the SF ₆ gas unit includes function code A _VI , the failure mode code is A ₁₄ , and the failure of A ₁₄ is described as SF ₆ gas unit The pressure is too low, the failure mode code is A ₁₅ , the failure description of A ₁₅ is the air leakage of the SF ₆ gas unit, the failure mode code is A ₁₆ , the failure description of A ₁₆ is the damp of the SF ₆ gas unit, the failure The mode code is A ₁₇ , and the failure of said A ₁₇ is described as a discharge of the SF ₆ gas unit.

Compared with the prior art, the present invention has the following advantages: the present invention conducts systematic risk assessment of DC transmission wall bushings based on preventive tests, online monitoring data, and manual inspection data, and at the same time breaks through the current single-purpose preventive test or online Risk assessment based on monitoring data or manual inspection data improves DC system operation reliability.

Description of drawings

Fig. 1 is the structural block diagram of the DC transmission wall bushing risk assessment system of the present invention;

Fig. 2 is the data transmission schematic diagram of preventive test instrument of the present invention;

Fig. 3 is a schematic diagram of data transmission of the online monitoring device of the present invention;

4 is a schematic diagram of data transmission of the mobile device of the present invention;

Fig. 5 is a schematic flow chart of the risk assessment method for DC transmission wall bushings of the present invention.

Among them: 1. DC transmission wall bushing; 2. Preventive test equipment; 21. Dielectric loss tester; 22. Gas component analyzer; 23. Moisture measuring instrument; 24. Temperature measuring instrument; 25. Air pressure measurement 26. DC resistance measuring instrument; 27. Contamination measuring instrument; 3. On-line monitoring device; 31. On-line monitoring instrument for ambient temperature; 32. On-line monitoring instrument for environmental humidity; 33. On-line monitoring instrument for surface contamination; Capacitance and dielectric loss on-line monitor; 35. SF ₆ density on-line monitor; 36. Pressure on-line monitor; 37. Moisture content on-line monitor; 38. Gas component on-line monitor; 4. Mobile device; 5 . Communication device; 51. First wireless transceiver module; 52. Second wireless transceiver module; 53. Third wireless transceiver module; 54. Fourth wireless transceiver module; 6. Risk assessment center.

Detailed ways

The content of the present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Example:

Please refer to Fig. 1, the risk assessment system of the DC transmission wall bushing of the present invention includes a DC transmission wall bushing 1, a preventive test instrument 2, an online monitoring device 3, a mobile device 4, a communication device 5 and a risk assessment center 6 composition. The preventive test instrument 2 is used to obtain the preventive test data of the DC transmission wall bushing 1, the online monitoring device 3 is used to obtain the online monitoring data of the DC transmission wall bushing, the mobile device 4 is used to record the data of manual inspection, and the communication device 5 is responsible for transmitting the preventive test data, online monitoring data, and manual inspection data to the risk assessment center 6, and the risk assessment center 6 realizes the risk assessment of the DC transmission wall bushing 1 based on the above data, so as to ensure the safe and reliable operation of the DC system Provide evidence.

Please refer to shown in Figure 2, the preventive test instrument 2 includes a dielectric loss tester 21, a gas component analyzer 22, a micro-water measuring instrument 23, a temperature measuring instrument 24, an air pressure measuring instrument 25, a DC resistance measuring instrument 26, and a pollution measuring instrument. instrument 27, their input ends are all connected to the DC transmission wall bushing 1, and their output ends are connected to the first wireless transceiver module 51, and the other side of the first wireless transceiver module 51 is also connected to the fourth wireless transceiver module in sequence 54 and Center for Risk Assessment6. Wherein, there is a wireless connection between the preventive test instrument 2 and the first wireless transceiver module 51; the risk assessment center 6 is connected with the fourth wireless transceiver module 54 through a serial port; the first wireless transceiver module 51 is connected to the fourth wireless transceiver module through a wireless network. Module 54 , realizing the transmission of preventive test data to the risk assessment center 6 .

See also shown in Figure 3, similar to the transmission structure of the preventive test instrument 2, the on-line monitoring device 3 includes an on-line temperature monitor 31, an on-line humidity monitor 32, a surface pollution on-line monitor 33, and the capacitance of the last screen And dielectric loss on-line monitor 34, SF ₆ density on-line monitor 35, pressure on-line monitor 36, micro-moisture content on-line monitor 37 and gas component on-line monitor 38, their input ends are all connected with direct current transmission wall sleeve Both the tube 1 connection and the output end are connected to the second wireless transceiver module 52 . On the other side of the second wireless transceiver module 52, a fourth wireless transceiver module 54 and the risk assessment center 6 are sequentially connected.

Please refer to shown in Fig. 4, mobile device 4 is a kind of mobile electronic equipment that has the 3rd wireless transceiver module 53, its data is read by the temperature and pressure data that on-site inspection personnel and data are stored in this mobile electronic equipment, and by The third wireless transceiver module 53 transmits, and the fourth wireless transceiver module 54 and the risk assessment center 6 are sequentially connected to the other side of the third wireless transceiver module 53 .

2-4, the communication device 5 includes a first wireless transceiver module 51 connected to the output of the preventive testing instrument 2, a second wireless transceiver module 52 connected to the output of the on-line monitoring device 3, and a mobile device 4 The third wireless transceiver module 53 that is connected to the output end of the mobile device 4 and integrated with the mobile device 4, and the fourth wireless transceiver module 54 that is connected to the input end of the risk assessment center 6, wherein the first wireless transceiver module 51, the second Both the wireless transceiver module 52 and the third wireless transceiver module 53 perform data transmission with the fourth wireless transceiver module 54 through a wireless network.

In this embodiment, the DC transmission wall bushing 1 adopts HSPHOCHSPANNUNGSGERATEKOLN/GERMAN DC transmission wall bushing, the first wireless transceiver module 51, the second wireless transceiver module 52, the third wireless transceiver module 53, and the fourth wireless transceiver module 54 Both use GEMOTECH’s R-8552/8554GPRSDTU, the dielectric loss tester 21 uses the YHJS-IV dielectric loss tester from Shanghai Yihong Electric Technology Co., Ltd., and the gas component analyzer 22 uses GC-7960 from Tengzhou Allen Analytical Instrument Co., Ltd. Type gas chromatograph, micro-water measuring instrument 23 adopts RTWS-242SF ₆ micro-water measuring instrument of Huatian Power Company, temperature measuring instrument 24 adopts DSC-DTSnK-XB of Dean Instrument, and air pressure measuring instrument 25 adopts HQ- SY-C precision digital pressure gauge, DC resistance measuring instrument 26 adopts PC57 DC resistance measuring instrument of Shanghai Taiou Electronics Co., Ltd., pollution measuring instrument 27 adopts NDYMD digital direct-reading intelligent salt density test of Wuhan Nandian Huayuan Electric Co., Ltd. The risk assessment center 6 adopts Dell PowerEdge R410, the environmental temperature online monitor 31 adopts DSC-DTSnK-XB of Beijing Dean Kangshuo Technology Development Co., Ltd., and the environmental humidity online monitor 32 adopts ETH-P16 environmental test equipment temperature and humidity patrol NDYMD digital direct-reading intelligent salt density tester from Wuhan Nandian Huayuan Electric Co., Ltd. 33 is used as the surface pollution online monitor, and ZF-800 from Henan Zhongfen is used as the on-line monitor 34 for the capacitance and dielectric loss of the last screen. -3 type capacitive equipment on-line monitor, SF ₆ density on-line monitor 35 adopts Y-100-type from Yichang Special Instrument Factory, pressure on-line monitor 36 adopts HQ-SY-C precision digital pressure gauge from Hongqi Instrument, The micro-water content online monitor 37 adopts the RTWS-242SF ₆ micro-water measuring instrument of Huatian Electric Power Company, the gas component online monitor 38 adopts the GC-7960 gas chromatograph of Tengzhou Allen Analytical Instrument Co., Ltd., and the mobile device 4 Adopt the G23OneX type of HTC Company.

See Figure 5. The risk assessment center 6 of the DC transmission wall bushing conducts the risk assessment of the DC transmission wall bushing 1 based on the preventive test data, online monitoring device data, and inspection data. The method steps are as follows:

S101. Extracting feature quantities for risk assessment of DC transmission wall bushings.

According to the preventive test data, on-line monitoring data, and inspection data obtained by the fourth wireless transceiver module 54, extract the feature quantity of the risk assessment of the DC transmission wall bushing, and form the vector C of the feature quantity value, and the vector C is 1× B-dimensional vector, B is the total number of characteristic components of the risk assessment of DC transmission wall bushings, in this embodiment, B=20, according to the monitoring results, obtain the vector C as shown in data (5):

$\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{c}\mathrm{<span\; class="notranslate">\; 3.5</span>}\\ \mathrm{<span\; class="notranslate">\; 2.6</span>}\\ <span\; class="notranslate">\; .</span>\\ <span\; class="notranslate">\; .</span>\\ <span\; class="notranslate">\; .</span>\\ \mathrm{<span\; class="notranslate">\; 2.07</span>}\end{array}\right]<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

Among them, each characteristic quantity C _j of vector C (j is a positive integer not greater than 20) respectively represents: characteristic quantity C ₁ is the insulation resistance of the DC transmission wall bushing guide rod to the end screen preventive test; characteristic quantity C ₂ is the capacitance of the preventive test of the guide rod of the DC transmission wall bushing to the final screen; the characteristic quantity C ₃ is the dielectric loss of the preventive test of the guide rod of the DC transmission wall bushing to the final screen; the characteristic quantity C ₄ is the DC transmission The insulation resistance of the ground-to-ground preventive test of the end screen of the wall-piercing bushing; the characteristic quantity C ₅ is the capacitance of the ground-to-ground preventive test of the end-screen of the DC transmission wall-piercing bushing; the characteristic quantity C ₆ is the end-screen of the DC transmission wall-through bushing The dielectric loss of the preventive test to the ground; the characteristic quantity C ₇ is the DC resistance of the preventive test of the guide rod of the DC transmission wall bushing; the characteristic quantity C ₈ is the pressure of the preventive test of the DC transmission wall bushing; the characteristic quantity C ₉ is the gas composition of the preventive test of the DC transmission wall bushing; the characteristic quantity C ₁₀ is the pollution value of the preventive test of the DC transmission wall bushing; the characteristic quantity C ₁₁ is the ambient temperature of the online monitoring of the DC transmission wall bushing ; The characteristic quantity C ₁₂ is the environmental humidity of the online monitoring of the DC transmission wall bushing; the characteristic quantity C ₁₃ is the pollution value of the online monitoring of the DC transmission wall bushing; the characteristic quantity C ₁₄ is the end of the online monitoring of the DC transmission wall bushing The capacitance and dielectric loss of the screen; the characteristic quantity C ₁₅ is the density of SF ₆ gas monitored online by the DC transmission wall bushing; the characteristic quantity C ₁₆ is the online monitoring pressure of the DC transmission wall bushing; the characteristic quantity C ₁₇ is the direct current Micro water in online monitoring of power transmission wall bushing; characteristic quantity C ₁₈ is the gas composition of on-line monitoring of DC transmission wall bushing; characteristic quantity C ₁₉ is the inspection pressure of DC transmission wall bushing; characteristic quantity C ₂₀ is DC The temperature of the transmission wall bushing inspection.

S102. Establish a failure mode of the risk assessment system for the DC transmission wall bushing.

According to the system composition function of the DC transmission wall bushing, the fault types for the bushing core unit, capacitor core unit, end screen unit, pressure equalizing ring unit, silicone rubber jacket unit, and SF ₆ gas unit are established. The above fault types include function codes, fault mode codes, and fault descriptions. The failure mode results are shown in Table 1:

Table 1

S103. Establishing a risk occurrence probability for the risk assessment of the DC transmission wall bushing.

According to the characteristic quantity of the risk assessment of the DC transmission wall bushing, the risk occurrence probability of the risk assessment of the DC transmission wall bushing is established; the attention value of each characteristic quantity C _j of the vector C is divided into an upper limit value a _j or a lower limit value b _j , respectively adopt the calculation formulas of risk occurrence probability such as formula (6) and (7), and form the risk occurrence probability vector D:

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}^{\mathrm{<span\; class="notranslate">\; 2.3</span>}}}{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}^{\mathrm{<span\; class="notranslate">\; 2.3</span>}}<span\; class="notranslate">\; +</span>{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}^{\mathrm{<span\; class="notranslate">\; 2.3</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

${\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\mathrm{<span\; class="notranslate">\; 0.46</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 0.46</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}\frac{\mathrm{<span\; class="notranslate">\; 3.11</span>}}{\mathrm{<span\; class="notranslate">\; 1.96</span>}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 0.93</span>}<span\; class="notranslate">\; *</span>{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; )</span>& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& {\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; b</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}\end{array}\right.<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 7</span>}<span\; class="notranslate">\; )</span>$

In this embodiment, the upper limit a _j and the lower limit b _j corresponding to each characteristic quantity C _j are as follows: b ₁ =10GΩ; b ₂ =-5%; a ₃ =0.8; b ₄ =1GΩ; b ₅ = -5%; b ₆ = -2%; b ₇ = -1%; b ₈ = _8Mpa ; a ₉ = 100 μL/L; a ₁₀ = 0.3 mg/cm ² ; a ₁₁ = 80°C; 85%; a ₁₃ = 0.3mg/cm ² ; b ₁₄ = -2%; b ₁₅ = 8kg/m ³ ; b ₁₆ = 8MPa; a ₁₇ = 500μL/L; a ₁₈ = 100μL/L; b ₁₉ = 8MPa ; a ₂₀ =30°C, substituting the above values and data (5) into formulas (6) and (7), the risk occurrence probability vector D is obtained as a 1×20-dimensional vector:

$\mathrm{<span\; class="notranslate">\; D.</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{c}\mathrm{<span\; class="notranslate">\; 0.35</span>}\\ \mathrm{<span\; class="notranslate">\; 0.15</span>}\\ <span\; class="notranslate">\; .</span>\\ <span\; class="notranslate">\; .</span>\\ <span\; class="notranslate">\; .</span>\\ \mathrm{<span\; class="notranslate">\; 0.023</span>}\end{array}\right]<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; )</span>$

S104. Establish a correlation matrix between the risk occurrence probability and the failure mode of the direct current transmission wall bushing.

According to the risk occurrence probability established by the characteristic quantity of the risk assessment of the DC transmission wall bushing, the correlation matrix M is established by combining the relationship between the characteristic quantity and the failure mode, and its size is E×B, where E represents the total number of failure modes, and its correlation matrix M The calculation method of the element M _ij of is as formula (9):

${\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; m</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; |</span>}{<span\; class="notranslate">\; |</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; |</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 9</span>}<span\; class="notranslate">\; )</span>$

In the formula, D _j and D _i respectively represent the components of the j and i risk occurrence probability vectors. In this embodiment, it can be seen from Table 1 that there are 6 types of failures and a total of 17 failure modes (i.e. E=17). Therefore, In this embodiment, i is a positive integer not greater than 17, and substituting data (8) into formula (9) can obtain a 17×20-dimensional relationship matrix M as shown in data (10):

$\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{cccc}\mathrm{<span\; class="notranslate">\; 0.22</span>}& \mathrm{<span\; class="notranslate">\; 0.13</span>}& <span\; class="notranslate">\; ...</span>& \mathrm{<span\; class="notranslate">\; 0.29</span>}\\ \mathrm{<span\; class="notranslate">\; 0.19</span>}& \mathrm{<span\; class="notranslate">\; 0.02</span>}& <span\; class="notranslate">\; ...</span>& \mathrm{<span\; class="notranslate">\; 0.31</span>}\\ <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>\\ <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>\\ <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>& <span\; class="notranslate">\; .</span>\\ \mathrm{<span\; class="notranslate">\; 0.61</span>}& \mathrm{<span\; class="notranslate">\; 0.15</span>}& <span\; class="notranslate">\; ...</span>& \mathrm{<span\; class="notranslate">\; 0.18</span>}\end{array}\right]<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 10</span>}<span\; class="notranslate">\; )</span>$

S105. Establishing a risk assessment method for the risk assessment of the direct current transmission wall bushing.

According to the characteristic quantity, risk occurrence probability and correlation matrix of the risk assessment of the DC transmission wall bushing, the bushing core unit, capacitor core unit, end screen unit, pressure equalizing ring unit, silicone rubber jacket unit, SF ₆ gas The risk assessment of the unit, its calculation method is as formula (11);

${\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\underset{\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; B</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; m</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; \&Center\; Dot;</span>{\mathrm{<span\; class="notranslate">\; D.</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}<span\; class="notranslate">\; *</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}}}{\mathrm{<span\; class="notranslate">\; 1.35</span>}<span\; class="notranslate">\; -</span>\underset{\mathrm{<span\; class="notranslate">\; k</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; j</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; h</span>}}_{\mathrm{<span\; class="notranslate">\; k</span>}}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 11</span>}<span\; class="notranslate">\; )</span>$

In the formula, A _i is the i-th failure mode, H _j and H _k represent the entropy of the j-th and k-th (it can be seen that k is a positive integer not greater than j) feature quantities, and the value range of the entropy is ( 0, 0.65), and substituting data (8) and data (10) into formula (11), the 1×17-dimensional risk evaluation vector A can be obtained, as shown in data (12):

$\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; =</span>\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\\ {\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\\ <span\; class="notranslate">\; .</span>\\ <span\; class="notranslate">\; .</span>\\ <span\; class="notranslate">\; .</span>\\ {\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 17</span>}}\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{c}\mathrm{<span\; class="notranslate">\; 0.023</span>}\\ \mathrm{<span\; class="notranslate">\; 0.19</span>}\\ <span\; class="notranslate">\; .</span>\\ <span\; class="notranslate">\; .</span>\\ <span\; class="notranslate">\; .</span>\\ \mathrm{<span\; class="notranslate">\; 0.046</span>}\end{array}\right]<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 12</span>}<span\; class="notranslate">\; )</span>$

Therefore, according to the above data (12), it can be determined that the risk value of poor contact of the bushing core of the DC transmission wall bushing is 0.023, the partial discharge risk value of the bushing core of the DC transmission wall bushing is 0.19, and other failure modes The risk value of , and so on, and the maximum risk evaluation value of each unit is 0.538 (not shown) as the risk value of the direct current transmission wall bushing.

Effect analysis: Through the analysis of the above examples, it can be determined that the risk value of poor contact of the bushing core of the DC transmission wall bushing is 0.023, and the partial discharge risk value of the bushing core of the DC transmission wall bushing is 0.19. The risk value of DC transmission wall bushing is 0.538. Therefore, this method is based on preventive tests, online monitoring data, and manual inspection data for systematic risk assessment of DC transmission wall bushings. Risk assessment based on monitoring data or manual inspection data improves DC system operation reliability.

This example applies to:

1. Risk assessment of DC transmission wall bushings with voltage levels of ±500kV and above;

2. Operational risk analysis, condition-based maintenance, and auxiliary decision-making for DC transmission wall bushings with voltage levels of ±500kV and above.

The above detailed description is a specific description of the feasible embodiment of the present invention. This embodiment is not used to limit the patent scope of the present invention. Any equivalent implementation or change that does not deviate from the present invention should be included in the patent scope of this case. middle.

Claims (4)

1. adopt direct current transportation wall bushing risk evaluating system to carry out a method for risk assessment, it is characterized in that, it comprises the following steps:

(1) according to preventive trial data, online monitoring data, tour data, extract the characteristic quantity of direct current transportation wall bushing risk assessment, described characterizing magnitudes is formed vectorial C, and described vectorial C is 1 × B dimensional vector, and B is the characteristic quantity sum of direct current transportation wall bushing risk assessment;

(2) based on the composition function of direct current transportation wall bushing, establish for sleeving core subelement, capacitor core unit, end shield unit, grading ring unit, silastic material unit, SF ₆the fault type of gas cell, described fault type comprises function code, fault mode code, failure-description;

(3) according to the characteristic quantity of direct current transportation wall bushing risk assessment, the risk probability of happening of direct current transportation wall bushing risk assessment is set up; By each characteristic quantity C of vectorial C _jdemand value be divided into higher limit a _jor lower limit b _j, adopt the calculating formula of risk probability of happening such as formula (1) and (2) respectively, and form risk probability of happening vector D, described risk probability of happening vector D is 1 × B dimensional vector;

$D_j=\frac{C_j^{2.3}}{C_j^{2.3}+{a_j}^{2.3}}---\left(1\right)$

$D_j=\left\{\begin{array}{cc}0.46-0.46sin\frac{3.11}{1.96*b_j}(C_j-0.93*b_j)& C_j\&le;2b_j\\ 0& C_j>2b_j\end{array}\right.---\left(2\right)$

(4) according to the risk probability of happening that the characteristic quantity of direct current transportation wall bushing risk assessment is set up, the relation in conjunction with characteristic quantity and fault mode is associated matrix M, and its size is E × B, and wherein E represents the sum of fault mode, the element M of its incidence matrix M _ijcomputing method such as formula (3):

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

D in formula _jand D _irepresent the component of jth and i kind risk probability of happening vector respectively, i and j is all positive integer and 1≤i≤E, 1≤j≤B;

(5) according to the characteristic quantity of direct current transportation wall bushing risk assessment, risk probability of happening and incidence matrix, set up for sleeve pipe fuse, capacitor core, end shield, grading ring, silastic material, SF ₆the risk assessment vector A of gas cell, its computing method are such as formula (4);

$A_i=\underset{j=1}{\overset{B}{\&Sigma;}}\left(M_{i\&times;j}\&CenterDot;D_j*\frac{1-H_j}{1.35-\underset{k=1}{\overset{j}{\mathrm{\&Sigma;}}}{H}_k}\right)---\left(4\right)$

A in formula _ibe the risk assessment component of i-th kind of fault mode, H _jand H _krepresent the entropy of jth and k characteristic quantity, the span of described entropy is (0,0.65).

2. method according to claim 1, is characterized in that, described B=20, wherein:

Characteristic quantity C ₁for direct current transportation wall bushing guide rod is to the insulation resistance of end shield preventive trial;

Characteristic quantity C ₂for direct current transportation wall bushing guide rod is to the electric capacity of end shield preventive trial;

Characteristic quantity C ₃for direct current transportation wall bushing guide rod is to the dielectric loss amount of end shield preventive trial;

Characteristic quantity C ₄for the insulation resistance of direct current transportation wall bushing end shield preventive trial over the ground;

Characteristic quantity C ₅for the electric capacity of direct current transportation wall bushing end shield preventive trial over the ground;

Characteristic quantity C ₆for the dielectric loss amount of direct current transportation wall bushing end shield preventive trial over the ground;

Characteristic quantity C ₇for the direct current resistance of direct current transportation wall bushing guide rod preventive trial;

Characteristic quantity C ₈for the pressure of direct current transportation wall bushing preventive trial;

Characteristic quantity C ₉for the gas composition of direct current transportation wall bushing preventive trial;

Characteristic quantity C ₁₀for the filth value of direct current transportation wall bushing preventive trial;

Characteristic quantity C ₁₁for the environment temperature of direct current transportation wall bushing on-line monitoring;

Characteristic quantity C ₁₂for the ambient humidity of direct current transportation wall bushing on-line monitoring;

Characteristic quantity C ₁₃for the filth value of direct current transportation wall bushing on-line monitoring;

Characteristic quantity C ₁₄for electric capacity and the dielectric loss of the end shield of direct current transportation wall bushing on-line monitoring;

Characteristic quantity C ₁₅for the SF of direct current transportation wall bushing on-line monitoring ₆the density of gas;

Characteristic quantity C ₁₆for the pressure of direct current transportation wall bushing on-line monitoring;

Characteristic quantity C ₁₇for micro-water of direct current transportation wall bushing on-line monitoring;

Characteristic quantity C ₁₈for the gas composition of direct current transportation wall bushing on-line monitoring;

Characteristic quantity C ₁₉for the pressure that direct current transportation wall bushing is maked an inspection tour;

Characteristic quantity C ₂₀for the temperature that direct current transportation wall bushing is maked an inspection tour.

3. method according to claim 2, is characterized in that, each characteristic quantity C _jcorresponding higher limit a _jor lower limit b _jas follows: b ₁=10G Ω; b ₂=-5%, a ₃=0.8; b ₄=1G Ω; b ₅=-5%; b ₆=-2%; b ₇=-1%; b ₈=8Mpa; a ₉=100 μ L/L; a ₁₀=0.3mg/cm ²; a ₁₁=80 DEG C; a ₁₂=85%; a ₁₃=0.3mg/cm ²; b ₁₄=-2%; b ₁₅=8kg/m ³; b ₁₆=8MPa; a ₁₇=500 μ L/L; a ₁₈=100 μ L/L; b ₁₉=8MPa; a ₂₀=30 DEG C.

4. method according to claim 1, is characterized in that, described E=17, wherein:

The fault type of described sleeving core subelement comprises function code A _i, fault mode code is A ₁, described A ₁failure-description be the loose contact of sleeve pipe fuse, fault mode code is A ₂, described A ₂failure-description be the shelf depreciation of sleeve pipe fuse;

The fault type of described capacitor core unit comprises function code A _iI, fault mode code is A ₃, described A ₃failure-description be that capacitor core makes moist, fault mode code is A ₄, described A ₄failure-description be the aging of capacitor core unit, fault mode code is A ₅, described A ₅failure-description be the shelf depreciation of capacitor core unit;

The fault type of described end shield unit comprises function code A _iII, fault mode code is A ₆, described A ₆fault mode be that end shield unit makes moist, fault mode code is A ₇, described A ₇failure-description be the insulation ag(e)ing of end shield unit, fault mode code is A ₈, described A ₈failure-description be end shield unit shelf depreciation;

The fault type of described grading ring unit comprises function code A _iV, fault mode code is A ₉, described A ₉failure-description be the corrosion of grading ring, fault mode code is A ₁₀, described A ₁₀failure-description be the filth of grading ring unit;

The fault type of described silastic material unit comprises function code A _v, fault mode code is A ₁₁, described A ₁₁failure-description be the aging of silastic material unit, fault mode code is A ₁₂, described A ₁₂failure-description be the filth of silastic material unit, fault mode code is A ₁₃, described A ₁₃failure-description be the cracking of silastic material unit;

Described SF ₆the fault type of gas cell comprises function code A _vI, fault mode code is A ₁₄, described A ₁₄failure-description be SF ₆the hypotony of gas cell, fault mode code is A ₁₅, described A ₁₅failure-description be SF ₆the gas leakage of gas cell, fault mode code is A ₁₆, described A ₁₆failure-description be SF ₆making moist of gas cell, fault mode code is A ₁₇, described A ₁₇failure-description be SF ₆the electric discharge of gas cell.