CN106249141A - Primary cut-out graphite contact wear detecting method - Google Patents

Abstract

Present invention relates particularly to a kind of primary cut-out graphite contact wear detecting method, belong to power switchgear on-line monitoring field.Comprise the following steps: step 1, calculate the absolute wear extent of High Voltage Circuit Breaker Contacts by meter and arc time weighting Evaluation Method；Step 2, calculates the relative electrical wear of contact and relative electric life method；Step 3, with SF₆Contact of breaker is calculated relative to electrical wear amount for dielectric；Step 4, evaluates contact of breaker.Its advantage is: calculate the absolute wear extent of High Voltage Circuit Breaker Contacts by meter and arc time weighting Evaluation Method, this method can add up the electrical wear situation that three-phase is lifted one's head respectively, and according to the electrical wear amount of arc time calculating single drop-out current, therefore can accurately judge the electric life of chopper.And energy monitoring breaker arc-chutes electric life in real time, can effectively understand the internal aging situation of arc-chutes, it is ensured that enough cut-offs capacity, prevent the generation of great pernicious fault, ensure the safe and stable operation of electrical network.

Description

Primary cut-out graphite contact wear detecting method

Technical field

The present invention relates to power switchgear on-line monitoring field, be specifically related to a kind of primary cut-out graphite contact abrasion Detection method.

Background technology

Along with planning and the application development of intelligent power grid technology, intelligent distribution network smart machine and correlation technique demand are continuous Increase.Chopper is to ensure that the security guard that system normal table runs in power system, its in systems play control and The dual function of protection.Along with technology and the development of application demand, Study of intelligent and the application technology to power high voltage switch System operations staff and the higher attention of researcher are obtained.Chopper is core particularly important in whole power system Equipment, its safe operation is most important, due to all many reasons such as circuit breaker design, manufacture, quality of materials and operations, if Standby pernicious fault happens occasionally, and has had a strong impact on the safe and stable operation of electrical network.The detection skill of arc-extinguishing chamber of circuit breaker electric life Art is the major prognostic means that chopper residual life is anticipated, belongs to more ripe, degree of recognition in numerous similar detection methods Higher detection, method for predicting, but in recent years in view of the construction energetically of domestic intelligent grid, a large amount of producers start to produce similar Product, from the point of view of operational effect, the existing successful case utilizing circuit breaker electrical endurance monitoring apparatus to note abnormalities, avoiding accident to occur Example, the situation also having substantial amounts of device wrong report to occur, fails to report, therefore it is badly in need of a kind of stable detection technique.

Summary of the invention

The technical problem to be solved is to provide the detection method in a kind of chopper service life, and it can be supervised in real time Survey arc-extinguishing chamber of circuit breaker electric life, can effectively understand the internal aging situation of arc-chutes, it is ensured that enough cut-offs capacity, prevent great The generation of pernicious fault, ensures the safe and stable operation of electrical network.

The technical solution adopted in the present invention is as follows:

Present invention relates particularly to a kind of primary cut-out graphite contact wear detecting method, belong to power switchgear online Monitoring field, comprises the following steps:

Step 1, calculates the absolute wear extent of High Voltage Circuit Breaker Contacts, computing formula by meter and arc time weighting Evaluation Method Such as following formula；

$Q_g=K_w{K}_g\underset{I}{\overset{N}{\Σ}}{\∫}_0^{\∂i}{\[ibi\left(t\right)\]}^{l}dt$

K in formula_wFor constant, with arc-extinguishing medium, cooling condition, contact movement velocity, contact material etc. is relevant, K_gFor ratio Coefficient；β is constant, relevant with contact material, and value between 1 and 2 typically takes 2.

Step 2, calculates relative electrical wear and relative electric life method, the computing formula such as following formula of contact；

Q_g=M × N=m × N_I

Q_M=1/N

Q_m=1/N_I

L=L_I-∑Q_m

Wherein Q_MWear extent, Q is cut-off for brand-new chopper single under the conditions of specified drop-out current_mBreak for brand-new The single of road device cut-offs wear extent, and M is that chopper single under the conditions of specified drop-out current cut-offs wear extent, and m is chopper Single cut-offs wear extent, the open and close times that N is allowed by the specified drop-out current of chopper, N₁Secondary for cut-offfing of chopper permission Number, L_IFor the initial value of circuit breaker electrical endurance, being the percent of one no more than 1, its value is determined by the history run of chopper, The L of that newly put into operation or after overhaul chopper_IDesirable 1, L are that chopper is relative to electric life.

Step 3, with SF₆Contact of breaker is calculated relative to electrical wear amount for dielectric；

Step 4, evaluates contact of breaker.

On the basis of technique scheme, the present invention can also improve as follows:

Further, described step 4 uses the algorithm of current squaring and time integral.

It is an advantage of the current invention that: it is exhausted that the present invention calculates High Voltage Circuit Breaker Contacts by meter and arc time weighting Evaluation Method To wear extent, this method can add up the electrical wear situation that three-phase is lifted one's head respectively, and cut-offs according to arc time calculating single The electrical wear amount of electric current, therefore can accurately judge the electric life of chopper.And can real-time monitoring breaker arc-chutes Electric life, can effectively understand the internal aging situation of arc-chutes, it is ensured that enough cut-offs capacity, prevents sending out of great pernicious fault Raw, ensure the safe and stable operation of electrical network.

Accompanying drawing explanation

Fig. 1 is the schematic flow sheet of the primary cut-out graphite contact wear detecting method described in the present embodiment.

Detailed description of the invention

Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail.Want according to following explanation and right Book, advantages and features of the invention is asked to will be apparent from.It should be noted that, accompanying drawing all uses the form simplified very much and all uses non- Ratio accurately, only in order to facilitate, to aid in illustrating lucidly the purpose of the embodiment of the present invention.

Embodiment

As it is shown in figure 1, present invention relates particularly to a kind of primary cut-out graphite contact wear detecting method, belong to electric power and open Close equipment on-line monitoring field, comprise the following steps:

Step 1, calculates the absolute wear extent of High Voltage Circuit Breaker Contacts, computing formula by meter and arc time weighting Evaluation Method As follows；

K in formula_wFor constant, with arc-extinguishing medium, cooling condition, contact movement velocity, contact material etc. is relevant, K_gFor ratio Coefficient；β is constant, relevant with contact material, and value between 1 and 2 typically takes 2.

The absolute wear extent of contact calculates it is to be appreciated that arc time and arcing current, in the feelings that cannot determine the arc time Under condition, calculate more difficulty.The automatic monitoring program utilizing drop-out current can get arc time and arcing circuit, thus calculates Go out the absolute wear extent of contact.

Step 2, calculates relative electrical wear and relative electric life method, the computing formula such as following formula of contact；

Q_g=M × N=m × N_I... ... formula (2)

Q_M=1/N ... ... formula (3)

Q_m=1/N_I... ... formula (4)

L=L_I-∑Q_m... ... formula (5)

Wherein Q_MWear extent, Q is cut-off for brand-new chopper single under the conditions of specified drop-out current_mBreak for brand-new The single of road device cut-offs wear extent, and M is that chopper single under the conditions of specified drop-out current cut-offs wear extent, and m is chopper Single cut-offs wear extent, the open and close times that N is allowed by the specified drop-out current of chopper, and N1 is that cut-offfing of chopper permission is secondary Number, L_IFor the initial value of circuit breaker electrical endurance, being the percent of one no more than 1, its value is determined by the history run of chopper, The L of that newly put into operation or after overhaul chopper_IDesirable 1, L are that chopper is relative to electric life.

Step 3, with SF₆Contact of breaker is calculated relative to electrical wear amount for dielectric；

Chopper is with SF₆For dielectric, therefore take equation below, substitute into respectively and calculate contact of breaker relative to electrical wear Amount.SF₆Contact of breaker is relative to electrical wear formula such as following formula (6) and formula (7):

Q_m=[1/ (5.9475 × (0.35 × I_e/I_c)_α)]1/N0.151I_e≤I_c＜ 0.35I_e... ... formula (6)

Q_m=[1/ (3.25 × (0.5 × I_e/I_c)_β)]1/NI_c≥0.35I_e... ... ... formula (7)

In formula, d and β is constant, relevant with contact material, between 1 and 2 value, typically takes 2.

At 0.03I_e≤I_c＜ 0.15I_eIn the range of the electrical wear corresponding to drop-out current can use linear interpolation method meter Draw.

Therefore the relative electric life L of chopper can be by formula L=L_I-∑Q_mObtain, L ＞ 0, illustrate that chopper is still in just Often running status, L≤0 explanation chopper is badly in need of maintenance, it is impossible to continue to run with.

Based on above method, primary cut-out specified drop-out current I_c=31.5KA, first drop-out current I_c=29.5KA Permission open and close times N=3000 under rated current, β=2 chopper initial value L_I=1 due to I_c≥0.35I_e

Therefore the relative electrical wear of chopper is: Qm=[1/ (3.25 × (0.5 × Ie/Ic) β)] 1/N=2.92x10^-5

The relative electric life of chopper is: L=L_I-∑Q_m＞ 0, illustrates that chopper is in normal operating condition.

Step 4, evaluates contact of breaker.

On the basis of technique scheme, the present invention can also improve as follows:

Further, described step 4 uses the algorithm of current squaring and time integral.

It is an advantage of the current invention that: it is exhausted that the present invention calculates High Voltage Circuit Breaker Contacts by meter and arc time weighting Evaluation Method To wear extent, this method can add up the electrical wear situation that three-phase is lifted one's head respectively, and cut-offs according to arc time calculating single The electrical wear amount of electric current, therefore can accurately judge the electric life of chopper.And can real-time monitoring breaker arc-chutes Electric life, can effectively understand the internal aging situation of arc-chutes, it is ensured that enough cut-offs capacity, prevents sending out of great pernicious fault Raw, ensure the safe and stable operation of electrical network.

Obviously, those skilled in the art can carry out various change and the modification spirit without deviating from the present invention to invention And scope.So, if the present invention these amendment and modification belong to the claims in the present invention and equivalent technologies thereof scope it In, then the present invention is also intended to change and including modification include these.

Claims (2)

1. a primary cut-out graphite contact wear detecting method, it is characterised in that comprise the following steps:

Step 1, calculates the absolute wear extent of High Voltage Circuit Breaker Contacts by meter and arc time weighting Evaluation Method, and computing formula is as follows Formula；

$Q_g=K_w{K}_g\underset{I}{\overset{N}{\Σ}}{\∫}_0^{\∂i}{\[ibi\left(t\right)\]}^{l}dt$

K in formula_wFor constant, with arc-extinguishing medium, cooling condition, contact movement velocity, contact material etc. is relevant, K_gFor proportionality coefficient； β is constant, relevant with contact material, and value between 1 and 2 typically takes 2；

Step 2, calculates relative electrical wear and relative electric life method, the computing formula such as following formula of contact；

Q_g=M × N=m × N_I

Q_M=1/N

Q_m=1/N_I

L=L_I-∑Q_m

Wherein Q_MWear extent, Q is cut-off for brand-new chopper single under the conditions of specified drop-out current_mFor brand-new chopper Single cut-off wear extent, M is that chopper single under the conditions of specified drop-out current cut-offs wear extent, and m is chopper single Cut-off wear extent, the open and close times that N is allowed by the specified drop-out current of chopper, N₁The open and close times allowed for chopper, L_IFor The initial value of circuit breaker electrical endurance, is the percent of one no more than 1, and its value is determined by the history run of chopper, newly puts into operation Or the L of chopper after overhaul_IDesirable 1, L are that chopper is relative to electric life；

Step 3, with SF₆Contact of breaker is calculated relative to electrical wear amount for dielectric；

Step 4, evaluates contact of breaker.

2. primary cut-out graphite contact wear detecting method as claimed in claim 1, it is characterised in that described step 4 is adopted Algorithm with current squaring Yu time integral.