CN101046502A - Cable running safety evaluating method - Google Patents

Abstract

The present invention is cable running safety monitoring method, evaluation method and device, and belongs to the field of cable running safety monitoring technology. The cable running safety monitoring method is to monitor overheat of cable wires and send alarm based on the preset fixed threshold and trend threshold. The cable running safety evaluation method includes recording cable surface temperature, environment temperature and cable current value regularly, establishing cable surface temperature regression model, predicting cable surface temperature trend, and performing the mathematic analysis on the predicted value and the measured value residual error to evaluate the cable running status. The present invention also proposes equipment comprising temperature measuring element, data transmission line, data acquiring circuit module, data converting circuit and computer. The present invention has temperature measuring precision up to 0.5 deg.c, fast storing and other advantages.

Description

A kind of cable running safety evaluating method

The application is an application number: 200510011911.5, and the applying date: on June 10th, 2005, denomination of invention: the dividing an application of a kind of monitoring of cable running safety, evaluation method and device thereof.

Technical field:

The invention belongs to the cable running safety monitoring technical field, be specifically related to cable running safety monitoring and cable running safety evaluating method and device thereof.

Background technology:

High-tension cable uses in modern industry enterprise frequently, has brought into play huge effect in industrial and agricultural production, but the thing followed is the occurrence probability cumulative year after year of cable fault.In case cable generation security incident, the lighter has a power failure, stop production to overhaul, and weight person will cause serious fire failure, and consequence is very serious, and repair is also extremely difficult, and its economic loss that causes can not be underestimated.Add up according to interrelated data, all kinds of power plant of China take place surplus the hot security incident 140 of cable over nearly 20 years, wherein reach unexpectedly in the period of the 1986-1992 7 75 times, there are 24 power plant that the above cable fire accident of secondary took place, indivedual power plant reach 4-6 time, wherein the loss that cable fire caused more than 70% is very serious, and 40% fire failure causes especially big loss.Carry out the cable security Study on Monitoring Technology,, avoid the generation of fire and explosion accident, have very significant meaning early detection cable fault hidden danger.

That the main inner reason of cable fault is that power cable joint is made is bad, crimping is tight, contact resistance is excessive and long-time running causes the overheated insulated envelope of burning of cable splice core conductor, further causes cable short circuit and causes fire.The external cause of cable fault is to cause outside wall temperature sharply to increase and initiation fire because outside high-power thermal source conducts heat.No matter be inner reason or external cause, thermal losses is too high to be the most basic factor that causes the hot security incident of cable.

At cable surface temperature anomaly is these characteristics of external sign of its hot stall, has had a lot of temp measuring methods to apply in the cable security supervisory system at present.Temperature-sensing element commonly used mainly contains infrared sensor, thermopair, thermistor, semiconductor PN, temperature control thyristor and integrated circuit type temperature sensor etc.The infrared sensor biggest advantage is a non-cpntact measurement, thereby has good security, and its shortcoming is complex structure, poor anti jamming capability, to the environmental requirement height; The thermopair transmission signals need be used special-purpose compensating line, and transmission range is unsuitable oversize, is not suitable for the cable temperature monitoring; Thermistor is generally platinum resistance, generally needs to adopt the three-wire type transmission, the output of balanced bridge formula, and transmission range is also unsuitable oversize, and anti-jamming capacity is relatively poor; Semiconductor PN type and temperature control thyristor-type sensor all are not suitable for the monitoring of cable temperature yet.

Therefore, be applied in the measurement of cable outside wall temperature the characteristics that disguise is high because the cable superheating phenomenon has, temperature rise in early age is slow, be difficult to detect although have multiple temp measuring method at present.Under normal conditions, be superheated to accident from cable end and take place, whole process slower development, overlong time, the temperature rise in early age phenomenon is not obvious, and current measuring methods is difficult to monitor effectively.Meanwhile, the reasons such as frequent fluctuation that have multi-layer compound structure and environment temperature owing to the cable outer wall, be difficult to calculate the analytic solution that obtain strictness by the heat transfer model of classics, based on cable surface temperature value and ambient temperature value analysis of trend is the important method that solves the cable security monitoring, and is the key problem that solves cable running safety monitoring and evaluation to the mathematical regression analysis of cable surface temperature and environment temperature and cable current variation relation.

The present invention has adopted advanced temperature-sensitive sensor and bussing technique, has developed a kind of cable surface temperature monitoring system of total digitalization, and laying is convenient, maintenance is simple, with low cost, antijamming capability is strong, has solved the problem that prior art exists preferably.What the present invention adopted is the important means that solves cable running safety monitoring and evaluation based on analysis of Influential Factors between cable surface temperature value and ring temperature, the cable current, by fixed threshold method and the real-time monitoring cable safe operation of trend threshold method state; Mathematical analysis by long-term measurement data, foundation is based on the cable meter temperature regression model of the gentle cable current of ring, the cable running safety state is proposed a kind of evaluation method of science, adopt temperature monitoring method of the present invention and corresponding algorithm software to solve the difficult problem of cable running safety monitoring and evaluation effectively.

Summary of the invention:

The invention provides a kind of cable running safety monitoring, evaluation method and device thereof, the cable core overheat condition is sent alerting signal automatically, realize real-time monitoring cable running safety by the intelligent decision of algorithm software.By mathematical analysis to long-term measurement data, foundation is based on the cable meter temperature regression model of the gentle cable current of ring, prediction cable surface temperature changing trend, compare by data with actual measured value, quality to the cable running status proposes evaluation index, remind the user in time to handle the cable abnormal occurrence, guarantee the high-tension cable safe operation.

The present invention includes temperature element 1, data line 2, data acquisition circuit assembly 3, data converting circuit 4, computing machine 5, cable 10 and control corresponding software.

The device of cable running safety monitoring of the present invention, evaluation is characterized in that it contains:

Temperature element 1, described temperature element are the semiconductor temperature-sensing probes, are encapsulated in the metal shell by heat-conducting glue, adopt Plastic Bandage described metal shell to be fixed on the outer wall of cable 10;

Data line 2, described data line are three core armouring signal wires, and its ground wire, data line and power lead link to each other with three pin of described temperature element respectively;

Data acquisition circuit assembly 3, described data acquisition circuit assembly contains micro-processor interface circuit 6, data acquisition circuit 7, communicating circuit 8 and power circuit 9, wherein:

Micro-processor interface circuit 6 contains:

Microprocessor is made of chip AVRMEGA16-16PI;

REST, DATA, CLK, WP waveshaping circuit are made of chip 24C021, and the REST of described waveshaping circuit, DATA, CLK, WP signal output part link to each other with the respective input of described microprocessor respectively;

COMM, EEPROM, ON/OFF, ERR, POWER indicator light circuit constitute by bleeder circuit with corresponding LED that it is just being gone here and there, the COMM of described indicator light circuit, EEPROM, ON/OFF, ERR, POWER signal output part, the negative pole of promptly corresponding each pilot lamp LED links to each other with the respective input of described microprocessor;

Data acquisition circuit 7 is bus types, contains:

Transistor control circuit, the acquisition controlling signal of described control circuit are that the grid of each triode links to each other with the corresponding control signal output terminal of described microprocessor;

Acquisition Circuit, it is made of the clamping diode circuit that links to each other with a bus, electric resistance partial pressure type signal acquisition circuit, and the signal output part of described two circuit all links to each other with the acquired signal input end of described microprocessor by described bus;

Communicating circuit 8 contains:

TX promptly sends waveshaping circuit, RX is that received signal forms circuit and OE promptly allows to send waveshaping circuit, they all are made of chip 6N136 respectively, and its TX input end, RX input end, OE output end signal port link to each other with described microprocessor respective input respectively;

The formation control circuit of TX, RX, each signal of OE is made of chip piece MAX485, and each control signal output ends of this MAX485 chip links to each other with the signal input end of described TX, RX, OE formation circuit respectively;

Power circuit 9 contains:

Self powered supply is made of battery and the chip DY05S05 in parallel with this battery, and the output terminal of described chip is the 5V direct supply;

External power supply, the input end of described external power supply links to each other with chip XZER05/24S05 input end through behind the resettable fuse, and described chip is output as the 5V direct supply;

Data converting circuit 4, described data converting circuit link to each other with computing machine 5 after the RS485 conversion of signals of remote transmission is become the RS232 signal; In the described data converting circuit, each terminal of plug-in card J52 respectively with communicating circuit in each terminal of output terminal plug-in card J9 dock one by one; U52 becomes the Transistor-Transistor Logic level signal with the RS485 conversion of signals, delivers to U55 after U53, U54 isolate, and U55 is converted to Transistor-Transistor Logic level the RS232 interface of delivering to computing machine 5 behind the RS232 signal by J53.

Cable security method for supervising of the present invention, it realizes real-time monitoring to cable running safety according to fixed threshold and trend threshold value, it is characterized in that: it is realized according to following steps successively by computing machine:

Step 1. system initialization, the fixed threshold of input setting and the trend threshold value of setting respectively;

Described fixed threshold is finger ring border temperature alarming fixed threshold, cable current warning fixed threshold and cable meter temperature warning fixed threshold respectively.

Described trend threshold value is finger ring temperature rise temperature trend threshold value and cable meter temperature rise temperature trend threshold value respectively;

For environment temperature, variation of ambient temperature rate ε in n the adjacent moment _nDefine by following formula:

${\mathrm{\ϵ}}_n=\frac{t_n-t_{n-1}}{t_{n-1}-t_{n-2}}$

Wherein, t _n, t _N-1And t _N-2Be respectively three adjacent moment n, n-1 and n-2 ambient temperature measurement value;

For the cable meter temperature, n adjacent moment inner cable table temperature rate of change ε _n' define by following formula:

${\mathrm{\ϵ}}_n^{\′}=\frac{T_n-T_{n-1}}{T_{n-1}-T_{n-2}}$

Wherein, T _n, T _N-1And T _N-2Be respectively three adjacent moment n, n-1 and n-2 cable meter temperature measurement value;

Step 2. is read in cable meter temperature, the gentle cable current value of ring;

Step 3. judges whether the ring temperature surpasses the environment temperature warning fixed threshold of setting;

If surpass, then encircle temperature and exceed standard, report to the police and keeping records, system restarts;

If do not surpass, then change next procedure 4 over to;

Step 4. judges whether cable current surpasses the cable current warning fixed threshold of setting;

If surpass, then cable current exceeds standard, and reports to the police and keeping records, and system restarts;

If do not surpass, then change next procedure 5 over to;

Step 5. judges whether the cable meter temperature surpasses the cable meter temperature warning fixed threshold of setting;

If surpass, then the cable meter temperature exceeds standard, and reports to the police and keeping records, and system restarts;

If do not surpass, then change next procedure 6 over to;

Step 6. reads three adjacent time period inner cable table temperature and ambient temperature value from database;

Step 7. judges according to variation of ambient temperature rate computing method whether the variation of ambient temperature rate surpasses the environment temperature intensification trend threshold value of setting;

If exceed standard, then be judged as ring temperature rise temperature abnormality, fault alarm, keeping records, system restarts;

If do not exceed standard, then change next procedure 8 over to;

Step 8. judges according to cable meter temperature rate of change computing method whether cable meter temperature rate of change surpasses the cable meter temperature rise temperature trend threshold value of setting;

If exceed standard, then be judged as cable meter temperature rise temperature abnormality, fault alarm, keeping records, system restarts;

If do not exceed standard, then change next procedure 9 over to;

Step 9. storage data, system returns step 2 automatically;

Cable running safety evaluating method of the present invention, behind the automatic rejecting abnormalities alarm set point of computing machine, according to cable surface temperature, environment temperature and the cable current value of storing automatically in a period of time, foundation is based on the cable meter temperature regression model of the gentle cable current of ring, by Automatic Program system's residual error is carried out analyzing and processing, operation trend to cable carries out forecast analysis, by with measured value relatively evaluation index is proposed for the quality of cable running status, provide the hidden danger diagnosis report by Automatic Program, guarantee cable running safety.

Described circuit safety postitallation evaluation method, it is characterized in that: it is realized according to following steps successively by computing machine:

Step 1. system initialization;

Step 2. system rejects the unusual measured value of alert program record in the one-year age automatically;

Step 3. according to the historical data of one-year age stored, set up regression model and calculate corresponding regression coefficient according to following formula:

L _n＝a+bt _n+cI _n ²

In the formula: I _n---n cable current value constantly;

t _n---n ambient temperature value constantly;

L _n---the n cable meter temperature constantly that calculates by mathematical regression model;

A, b, c---regression equation undetermined parameter draws by the matrix of coefficients of finding the solution normal equations:

By normal equations: X ' XB=X ' Y, find the solution and obtain matrix of coefficients: B=(X ' X) ^-1X ' Y

Wherein $X=\left(\begin{array}{ccc}1& t_1& {I_1}^2\\ .& .& .\\ .& .& .\\ .& .& .\\ 1& t_{\mathrm{<figure-callout\; id="2"\; label="n\; I\; n"\; filenames="A20071008667000121.png,A20071008667000131.png"\; state="\{\{state\}\}">n</figure-callout>}}& {I_n}^{}{{}_{}}^2\end{array}\right),$ $Y=\left(\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="T"\; filenames="A20071008667000121.png,A20071008667000131.png"\; state="\{\{state\}\}">T</figure-callout>}}_1\\ .\\ .\\ .\\ T_n\end{array}\right),$ B is a matrix of coefficients $B=\left(\begin{array}{c}a\\ b\\ c\end{array}\right)$

Step 4. calculate the standard deviation sigma of cable meter temperature measurement value

$\mathrm{\&sigma;}=\sqrt{\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{(T_i-\stackrel{\&OverBar;}{T})}^2}$

In the formula: T _i---i is cable meter temperature measurement value constantly;

T---cable meter temperature average is calculated by following formula:

$\stackrel{\&OverBar;}{T}=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{T}_i$

Step 5. calculate cable meter temperature predicted value L _nWith measured value T _nBetween residual error δ _n=T _n-L _n

Step 6. according to 3 σ principles, 99% measured value should be in [3 σ, 3 σ] interval.By procedure judges residual error δ _nWhether in this interval:

If in this interval, then change step 7 over to;

If surpass this interval, then change step 8 over to;

Step 7. output " this section cable running status ' excellent ' " information provides operation curve;

Step 8. output " this section cable running status ' bad ' " information provides the hidden danger report;

Step 9. the cable fault inspection, system restarts.

Compare with existing cable security method for supervising, the present invention has following major advantage:

1). temperature-sensing probe is highly sensitive, and temperature measurement accuracy can reach ± and 0.5 ℃;

2). picking rate is fast, and temperature data and digital signal transformation time are not more than 15ms;

3). anti-electromagnetic interference capability is strong, anticorrosive property good, and is working properly under the strong-electromagnetic field environment;

4). the network enabled function, power system capacity is big, long transmission distance.Each data acquisition module can connect 8 circuit-switched data transmission lines, can be connected in series 64 probes on every single data transmission line;

5). system possesses the self check ability that reports an error, stable performance;

6). by the data line power supply, wiring is simple, cost is low, stable, it is simple to safeguard;

7). each temperature-sensing probe has the unique coding of 64bit, according to the corresponding relation of temperature-sensing probe position and its Digital ID sign indicating number, can determine the position of temperature anomaly point exactly, has solved the difficult problem of cable hidden danger location.

8). by the warning model cable fault is in time reported to the police, eliminate safe hidden trouble as early as possible;

9). regression model is set up in the mathematical analysis by long-term measurement data, the quality of automatic Evaluation cable running status.

The present invention is particularly suitable for the security monitoring and the long-time running state evaluation of high-tension cable and low voltage electrical equipment circuit, and is safe and convenient to use, can greatly improve the automatization level of cable security monitoring.

Description of drawings:

Fig. 1 systematic schematic diagram of the present invention;

Fig. 2 micro-processor interface circuit schematic diagram;

Fig. 3 data acquisition circuit schematic diagram;

Fig. 4 communicating circuit schematic diagram;

Fig. 5 power circuit principle figure;

Fig. 6 (a) data converting circuit schematic diagram;

The power circuit principle figure of Fig. 6 (b) data converting circuit;

Fig. 7 cable alert program operation of the present invention block diagram;

Fig. 8 cable security assessment process operation of the present invention block diagram.

Embodiment:

Specify embodiments of the present invention below in conjunction with accompanying drawing.

Embodiment 1:

Cable security monitoring of the present invention and postitallation evaluation method and device thereof are made up of temperature element 1, data line 2, data acquisition circuit assembly 3, data converting circuit 4, computing machine 5, cable 10 and Control Software thereof.

Temperature element 1 is meant 18B20 N-type semiconductor N temperature-sensing probe in the present embodiment, be encapsulated in the metal shell by heat-conducting glue, adopt Plastic Bandage that metal shell is fixed on the cable outer wall, three pin of temperature-sensing probe are connected with ground wire, data line and the power lead of data line 2 respectively, described data line 2 is made up of triple core wire, and the electric wire outer wall wraps up aluminium foil, copper mesh, inner restrictive coating, steel armour and external sheath layer respectively.

Data acquisition circuit assembly 3 in the present embodiment is made up of micro-processor interface circuit 6, data acquisition circuit 7, communicating circuit 8, power circuit 9.

Described micro-processor interface circuit 6 is used for data acquisition, system state shows, is made up of integrated circuit U1～U2, exclusion PR1～PR2, diode L1～L5, capacitor C 1～C3, resistance R 1～R22, crystal oscillator Y1.Wherein, 1 pin of U1,2 pin, 3 pin, 9 pin respectively with 6 pin of U2,5 pin, 3 pin, 7 pin correspondence one by one join, 4 pin of U1,5 pin, 6 pin, 7 pin, 8 pin respectively and L1, L2, L3, the negative electrode of L4 and L5 correspondence one by one joins, 10 pin of U1,11 pin respectively with the VCC of power supply, GND correspondence one by one joins, the end of C1, the end of Y1 and 12 pin of U1 join, the end of C2,13 pin of the other end of Y1 and U1 join, the other end of C1, the other end and the GND of C2 join, 14 pin of U1,15 pin, 16 pin respectively with communicating circuit 8 in R32, R33, the end of R31 correspondence one by one joins, 30 pin of U1,31 pin respectively with the VCC of power supply, GND correspondence one by one joins, 32 pin of U1 and the end of C3 join, the other end and the GND of C3 join, 22 pin of U1,23 pin, 24 pin, 25 pin, 26 pin, 27 pin, 28 pin, 29 pin, 33 pin, 34 pin, 35 pin, 36 pin, 37 pin, 38 pin, 39 pin, 40 pin respectively and R5, R7, R9, R11, R13, R15, R17, R19, R18, R16, R14, R12, R10, R8, R6, the end of R4 correspondence one by one joins, R5, R7, R9, R11, R13, R15, R17, the other end of R19 respectively with 9 pin of PR2,8 pin, 7 pin, 6 pin, 5 pin, 4 pin, 3 pin, 2 pin correspondence one by one join, 1 pin and the GND of PR2 join, R4, R6, R8, R10, R12, R14, R16, the other end of R18 respectively with data acquisition circuit 7 in 1 pin of J1,1 pin of J2,1 pin of J3,1 pin of J4,1 pin of J5,1 pin of J6,1 pin of J7,1 pin of J8 correspondence one by one joins, 2 pin of U2 and the end of R21 join, the other end and the GND of R21 join, 4 pin and the GND of U2 join, 8 pin and the VCC of U2 join, R1, R2, the end of R3 respectively with 5 pin of U2,6 pin, 7 pin correspondence one by one join, R1, R2, the other end and the VCC of R3 join, L2, L3, L4, the anode of L5 respectively with 2 pin of PR1,3 pin, 4 pin, 5 pin correspondence one by one join, 1 pin and the VCC of PR1 join, the end of the anode of L1 and R22 joins, and the other end and the VCC of R22 join.

Described data acquisition circuit 7 is made up of connection terminal J1～J8, exclusion PR3, diode D1～D16, triode Q1～Q8, capacitor C 5～C12, resistance R 23～R30.Wherein, the end of 9 pin of 1 pin of the negative electrode of the anode of D1, D2, J1, PR3, R23 joins.The end of 1 pin of the anode of D3, the negative electrode of D4, J2,8 pin of PR3, R24 joins.The end of 1 pin of the anode of D5, the negative electrode of D6, J3,7 pin of PR3, R25 joins.The end of 1 pin of the anode of D7, the negative electrode of D8, J4,6 pin of PR3, R26 joins.The end of 1 pin of the anode of D9, the negative electrode of D10, J5,5 pin of PR3, R27 joins.The end of 1 pin of the anode of D11, the negative electrode of D12, J6,4 pin of PR3, R28 joins.The end of 1 pin of the anode of D13, the negative electrode of D14, J7,3 pin of PR3, R29 joins.The end of 1 pin of the anode of D15, the negative electrode of D16, J8,2 pin of PR3, R30 joins.1 pin and the VCC of PR3 join, and negative electrode and the VCC of D1, D3, D5, D7, D9, D11, D13, D15 join.D2, D4, D6, D8, D10, D12, D14, anode and the GND of D16 join, J1, J2, J3, J4, J5, J6, J7,2 pin and the GND of J8 join, J1, J2, J3, J4, J5, J6, J7,3 pin and the VCC of J8 join, J1, J2, J3, J4, J5, J6, J7,4 pin and the earth E of J8 join, Q1, Q2, Q3, Q4, Q5, Q6, Q7, the grid of Q8 respectively and C5, C6, C7, C8, C9,10, C11, the end of C12 is corresponding one by one join after more respectively with micro-processor interface circuit 6 in 9 pin of PR2,8 pin, 7 pin, 6 pin, 5 pin, 4 pin, 3 pin, 2 pin correspondence one by one join, C5, C6, C7, C8, C9,10, C11, the other end of C12 respectively and R23, R24, R25, R26, R27, R28, R29, the other end of R30 after correspondence is joined one by one more respectively and Q1, Q2, Q3, Q4, Q5, Q6, Q7, the drain electrode of Q8 correspondence is one by one joined, Q1, Q2, Q3, Q4, Q5, Q6, Q7, source electrode and the GND of Q8 join.

Described communicating circuit 8 is made up of connection terminal J9, integrated circuit U3～U6, triode Q9, resistance R 31～R38, resettable fuse F1～F2.Wherein, U3, U4,3 pin of U5 respectively and R31, R35, the end of R33 correspondence one by one joins, 2 pin of U3,8 pin of U4,2 pin of U5, the other end and the VCC of R32 join, 8 pin of U3,2 pin of U4,8 pin of U5, the end of R34, the end of R36, the emitter-base bandgap grading of Q9,8 pin and the 5V of U6 join, U3,6 pin of U4 respectively and R37, the other end of R32 correspondence one by one joins, 6 pin of U5, the other end of R34,4 pin of U6 join, 5 pin of U3,5 pin of U5, the end of R38,5 pin of U6,5 pin and the 0V of J9 join, 5 pin and the GND of U4 join, the other end of R36, the other end of R37 and the base stage of Q9 are joined, the other end of R38, the collector of Q9,2 pin of U6,3 pin of U6 join, the other end of R35,1 pin of U6 joins, 6 pin of U6,7 pin respectively with the end of F1, the end of F2 correspondence one by one joins, the other end of F2,1 pin of J9,3 pin of J9 join, the other end of F1,2 pin of J9,4 pin of J9 join.

Described power circuit 9 is made up of connection terminal J10, integrated circuit U7～U8, resettable fuse F3, electric capacity E1～E4, capacitor C 16～C22.Wherein, 1 pin of J10 and the end of F3 join, 2 pin of J10, the end of C19, the end of C20, the negative pole of E3,2 pin of U8 join, 3 pin of J10, the other end of C19, the end of C18 and the end of C22 and the earth E join, the other end of F3, the other end of C20, the positive pole of E3,1 pin of U8 joins, the end of C21, the positive pole of E4,3 pin of U8, the positive pole of E1, the end of C16,14 pin and the VCC of U7 join, the other end of C21, the negative pole of E4,5 pin of U8, the other end of C22, the negative pole of E1, the other end of C16,1 pin and the GND of U7 join, the end of C17, the positive pole of E2,8 pin and the 5V of U7 join, the other end of C17, the negative pole of E2,9 pin of U7, the other end and the 0V of C18 join.

Described data converting circuit 4 is made up of connection terminal J51～J53, integrated circuit U51～U56, resistance R 51～R54, resettable fuse F51～F52, electric capacity E51～E52, capacitor C 51～C58.Wherein, 1 pin of J51, the positive pole of E51, the end of C51,14 pin and the VCC of U51 join, 2 pin of J51, the negative pole of E51, the other end of C51,1 pin and the GND of U51 join, 8 pin of U51, the end of C52, positive pole and the 5V of E52 join, 9 pin of U51, the other end of C52, negative pole and the 0V of E52 join, 1 pin of J52, the end of 3 pin and F52 joins, 2 pin of J52, the end of 3 pin and F51 joins, 6 pin of U52 and the other end of F1 join, 7 pin of U52 and the other end of F52 join, 5 pin of U52,5 pin and the GND of J52 join, 8 pin and the VCC of U52 join, 1 pin of U52 and the end of R53 join, 2 pin of U52,3 pin of 3 pin and U56 join, 4 pin of U52,1 pin of U56,6 pin of U54 and the end of R52 join, 3 pin of the other end of R53 and U53 join, 7 pin of U54,8 pin of U54,2 pin of U53, the end of C53, the other end and the VCC of R52 join, the other end and the GND of C53 join, 2 pin of U54,7 pin of U53,8 pin of U53, the end of C54, an end and the 5V of R54 join, 5 pin of U53, the other end and the 0V of C54 join, 6 pin of U53,11 pin of the other end of R54 and U55 join, 3 pin of U54 and the end of R51 join, 12 pin of the other end of R51 and U55 join, 1 pin of U55,3 pin join with the two ends of C58 respectively, 4 pin of U55,5 pin join with the two ends of C57 respectively, 2 pin of U55,6 pin respectively with the end of C55, the end of C56 correspondence one by one joins, the other end of C55, the other end of C56,5 pin and the 0V of J53 join, 13 pin of U55,14 pin respectively with 2 pin of J53,3 pin correspondence one by one join.

The control procedure of described cable security method for supervising is as follows: preestablish maximum environment temperature warning fixed threshold, cable current warning fixed threshold and the cable meter temperature warning fixed threshold that allows by the user behind the system initialization.Automatic Program is read in environment temperature, cable current and cable meter temperature value, judge at first successively whether environment temperature, cable current and cable meter temperature surpass the fixed threshold of setting, if surpass predefined fixed threshold then provide " the ring temperature exceeds standard ", " electric current exceeds standard " and " showing temperature exceeds standard " information successively, system sends to exceed standard and reports to the police and keeping records automatically, and reminds people is in time checked processing; If surpass fixed threshold, then from historical data base, read gentle cable meter temperature data difference computing environment rate of temperature change of ring and cable meter temperature rate of change in three adjacent moment.Calculate by program, judge whether the variation of ambient temperature rate surpasses the ring temperature rise temperature trend threshold value of setting.Variation of ambient temperature rate ε _nGive expression to environment temperature self rate of change, if ε _nChange too soon, normal head and shoulders above temperature fluctuation range then can be judged and exists extraneous thermal source that cable is conducted heat, thereby sends ring temperature rise temperature abnormality warning message; If do not surpass the ring temperature rise temperature trend threshold value of setting, then further calculate cable meter temperature rate of change ε _n' whether surpass the cable meter temperature rise temperature trend threshold value of setting, if exceed standard then send cable meter temperature rise temperature abnormality warning message, remind managerial personnel in time to handle, and preserve each alarm logging automatically, so that inquire about; If do not surpass the cable meter temperature rise temperature trend threshold value of setting, then read in next group measurement data again, thereby realize real-time monitoring the cable operation conditions.

The process of cable running safety evaluating method of the present invention is as follows: after 1 year, by program the cable running status is carried out analysis and assessment at cable running safety.At first behind the unusual measured value that the All Alerts program writes down in rejecting the described time limit, historical data in 1 year is carried out regretional analysis, set up regression model and calculate corresponding regression coefficient, calculate the standard deviation sigma of cable meter temperature measurement value and the residual error δ between cable meter temperature predicted value and the actual measured value by Automatic Program _n, according to 3 σ principles in the probability statistics, promptly 99% measured value should be judged the quality of cable running status automatically in fiducial interval [3 σ ,+3 σ], reminds managerial personnel in time to overhaul or find out potential safety hazard, has guaranteed cable running safety.

Claims (1)

1, a kind of cable running safety evaluating method, it is characterized in that: it is realized according to following steps successively by computing machine:

Step 1. system initialization;

Step 2. system rejects the unusual measured value of alert program record in the one-year age automatically;

Step 3. according to the historical data of one-year age stored, set up regression model and calculate corresponding regression coefficient according to following formula:

L _n＝a+bt _n+cI _n ²

In the formula: I _n--n cable current value constantly;

t _n--n ambient temperature value constantly;

L _n--the n cable meter temperature constantly that calculates by mathematical regression model;

A, b, c--regression equation undetermined parameter draw by the matrix of coefficients of finding the solution normal equations:

By normal equations: X ' XB=X ' Y, find the solution and obtain matrix of coefficients: B=(X ' X) ^-1X ' Y

Wherein $X=\left(\begin{array}{ccc}1& t_1& {I_1}^2\\ \&CenterDot;& \&CenterDot;& \&CenterDot;\\ \&CenterDot;& \&CenterDot;& \&CenterDot;\\ \&CenterDot;& \&CenterDot;& \&CenterDot;\\ 1& t_n& {I_n}^2\end{array}\right),$ $Y=\left(\begin{array}{c}{T}_1\\ \&CenterDot;\\ \&CenterDot;\\ \&CenterDot;\\ T_n\end{array}\right),$ B is a matrix of coefficients $B=\left(\begin{array}{c}a\\ b\\ c\end{array}\right)$

Step 4. calculate the standard deviation sigma of cable meter temperature measurement value

$\mathrm{\&sigma;}=\sqrt{\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{(T_i-\stackrel{\&OverBar;}{T})}^2}$

In the formula: T _i--i is cable meter temperature measurement value constantly;

T--cable meter temperature average is calculated by following formula:

$\stackrel{\&OverBar;}{T}=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{T}_i$

Step 5. calculate cable meter temperature predicted value L _nWith measured value T _nBetween residual error δ _n=T _n-L _n

Step 6. according to 3 σ principles, 99% measured value should be in [3 σ, 3 σ] interval.By procedure judges residual error δ _nWhether in this interval:

If in this interval, then change step 7 over to;

If surpass this interval, then change step 8 over to;

Step 7. output " this section cable running status ' excellent ' " information provides operation curve;

Step 8. output " this section cable running status ' bad ' " information provides the hidden danger report;

Step 9. the cable fault inspection, system restarts.

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