CN103983865A - Series reactor power capacitor group operating state real-time online monitoring method - Google Patents

Abstract

The invention relates to a series reactor power capacitor group operating state real-time online monitoring method. The method comprises the following steps: the first step in which initialization is performed when the power capacitor group of a target series reactor starts to be put into operation; and the second step in which the operating state of the power capacitor group of the target series reactor is monitored. According to the invention, by acquiring the current and the voltage of a same phase, capacitor elements in the capacitor group can be judged whether to be failed keenly, and if a failure exists, then early warning is performed timely, so advantages of high accuracy and good practicability can be realized.

Description

For the realtime on-line monitoring method of the power capacitor bank running status of current-limiting reactor

Technical field

The realtime on-line monitoring method that the present invention relates to a kind of power capacitor bank running status for current-limiting reactor, belongs to power capacitor bank monitoring technique field.

Background technology

According to the knowledge of the applicant, often adopt capacitor on-Line Monitor Device in power technology field, in order to can send early warning information before capacitor generation catastrophic failure, remind operational management personnel to carry out interruption maintenance to capacitor.The power capacitor of most is all made up of many capacity cell series and parallel connections, if one of them component wear cannot distinguish, cause other elements more easily to damage because of overvoltage or overcurrent.Adopt capacitor on-Line Monitor Device just in order to address this problem.

Judge whether fault of capacitor group, best criterion measures split-phase capacitor value C, can judge according to the variation of C whether there is component wear capacitor group inside, but the current/voltage angle of whole capacitor group approaches 90 degree substantially, directly the C value error of calculable capacitor is larger; Meanwhile, in the time that capacitor group internal capacitance element is damaged, the capacitor group of especially interior fuse, its current value variable quantity is very little, is often less than 0.5%, then the C value calculating thus almost cannot reflect fault.

Summary of the invention

Technical matters to be solved by this invention is: overcomes the problem that prior art exists, a kind of realtime on-line monitoring method of the power capacitor bank running status for current-limiting reactor is provided, and effectively failure judgement, and in the time that fault occurs, effectively send early warning.

The technical scheme that the present invention solves its technical matters is as follows:

For a realtime on-line monitoring method for the power capacitor bank running status of current-limiting reactor, comprise the following steps:

The first step, in the time that starting to put into operation, the power capacitor bank of target current-limiting reactor carries out initialization:

S1. gather power capacitor bank and connect the fundametal compoment of a phase busbar voltage in three-phase bus. , third-harmonic component. , quintuple harmonics component. , and taking this mutually as monitoring phase; Gather the fundametal compoment of electric current at power capacitor bank and the tie point of monitoring phase bus , third-harmonic component , quintuple harmonics component ;

S2. the loop of power capacitor bank is equivalent to resistance R _a, reactance L _a, capacitor C _aseries circuit; To following solving equations, draw the L in power capacitor bank loop _avalue and C _avalue:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{A1}*{\mathrm{j\ωL}}_A+{\stackrel{\·}{I}}_{A1}/\left({\mathrm{j\ωC}}_A\right)+{\stackrel{\·}{I}}_{A1}*R_A={\stackrel{\·}{U}}_{A1}\\ {\stackrel{\·}{I}}_{A3}*{j3\mathrm{\ωL}}_A+{\stackrel{\·}{I}}_{A3}/\left({j3\mathrm{\ωC}}_A\right)+{\stackrel{\·}{I}}_{A3}*R_A={\stackrel{\·}{U}}_{A3},\\ {\stackrel{\·}{I}}_{A5}*{j5\mathrm{\ωL}}_A+{\stackrel{\·}{I}}_{A5}/\left({j5\mathrm{\ωC}}_A\right)+{\stackrel{\·}{I}}_{A5}*R_A={\stackrel{\·}{U}}_{A5}\end{array}\right.$

Wherein, w is angular frequency, and j is the imaginary part of symbol;

S3. draw as follows the initial oscillation f in power capacitor bank loop _r0:

$f_{r0}=\frac{1}{2\mathrm{\π}\sqrt{L_A{C}_A}};$

S4. initialization is complete;

The running status of the power capacitor bank of second step, monitoring objective current-limiting reactor:

S5. gather the fundametal compoment of monitoring phase busbar voltage third-harmonic component quintuple harmonics component gather the fundametal compoment of electric current at power capacitor bank and the tie point of monitoring phase bus third-harmonic component quintuple harmonics component

S6. to following solving equations, show that power capacitor bank loop is current value and value:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{A1}^1*{\mathrm{j\ωL}}_A^1+{\stackrel{\·}{I}}_{A1}^1/\left({\mathrm{j\ωC}}_A^1\right)+{\stackrel{\·}{I}}_{A1}^1*R_A^1={\stackrel{\·}{U}}_{A1}^1\\ {\stackrel{\·}{I}}_{A3}^1*{j3\mathrm{\ωL}}_A^1+{\stackrel{\·}{I}}_{A3}^1/\left({j3\mathrm{\ωC}}_A^1\right)+{\stackrel{\·}{I}}_{A3}^1*R_A^1={\stackrel{\·}{U}}_{A3}^1,\\ {\stackrel{\·}{I}}_{A5}^1*{j5\mathrm{\ωL}}_A^1+{\stackrel{\·}{I}}_{A5}^1/\left({j5\mathrm{\ωC}}_A^1\right)+{\stackrel{\·}{I}}_{A5}^1*R_A^1={\stackrel{\·}{U}}_{A5}^1\end{array}\right.$

S7. draw as follows the current oscillation frequency in power capacitor bank loop

$f_r^1=\frac{1}{2\mathrm{\π}\sqrt{L_A^1{C}_A^1}};$

S8. be calculated as follows oscillation frequency rate of change l:

$\mathrm{\λ}=\frac{f_r^1}{f_{\mathrm{ro}}};$

S9. by l and the comparison of predetermined failure definite value, first send early warning and go to again S10 if l is greater than predetermined failure definite value, otherwise directly go to S10;

S10. judge whether to stop monitoring, go to if not S5 and continue monitoring, if monitoring finishes.

The loop of living in power capacitor of current-limiting reactor is equivalent to RLC series circuit by the method, then by gathering fundametal compoment, third-harmonic component, the quintuple harmonics component of electric current and voltage, draw equivalent inductance L and equivalent capacity C, more further draw oscillation frequency; Then, the oscillation frequency while starting to put into operation taking power capacitor is benchmark, continues to monitor oscillation frequency and changes, when variation exceeds predetermined value alarm.Can effectively realize like this early warning to capacitor, Reactor Fault.

The present invention further perfect technical scheme is as follows:

Preferably, in S9, definite method of predetermined failure definite value is as follows:

For benchmark phase bus, in power capacitor bank, contain M unit in parallel, each unit in parallel contains the capacitor of N series connection, and each capacitor contains m little unit in parallel, and each little unit in parallel contains the capacity cell of n series connection;

Default early-warning conditions is: early warning while puncturing k capacity cell;

Predetermined failure definite value is $\sqrt{1+\frac{k}{\mathrm{NMn}(m-k)+N(M-1)k}}.$

Adopt after this optimal technical scheme, can further effectively realize the early warning of fault.

Preferably, in S2, S6, the w=2f in system of equations, wherein f=50Hz.

The present invention can judge by the electric current and the voltage that gather same phase in capacitor group, whether capacity cell exists fault observantly, if exist fault to send in time early warning, precision is high, practical.

Brief description of the drawings

Fig. 1 is the FB(flow block) of the embodiment of the present invention 1.

Fig. 2 is the enforcement schematic diagram of Fig. 1 embodiment.

Embodiment

Below in conjunction with embodiment, the present invention is described in further detail.But the invention is not restricted to given example.

Embodiment

As shown in Figure 1 and Figure 2, the present embodiment comprises the following steps for the realtime on-line monitoring method of the power capacitor bank running status of current-limiting reactor:

The first step, in the time that starting to put into operation, the power capacitor bank 4 of target current-limiting reactor carries out initialization:

S1. gather the fundametal compoment of the power capacitor bank 4 phase busbar voltage in three-phase bus that connects. _uA1, third-harmonic component. , quintuple harmonics component. , and taking this mutually as monitoring phase; Gather the fundametal compoment of electric current at power capacitor bank 4 and the tie point of monitoring phase bus 1 , third-harmonic component , quintuple harmonics component .As shown in Figure 2, voltage acquisition point is 3, and current acquisition point is 2.

S2. the loop of power capacitor bank 4 is equivalent to resistance R _a, reactance L _a, capacitor C _aseries circuit; To following solving equations, draw the L in power capacitor bank 4 loops _avalue and C _avalue:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{A1}*{\mathrm{j\ωL}}_A+{\stackrel{\·}{I}}_{A1}/\left({\mathrm{j\ωC}}_A\right)+{\stackrel{\·}{I}}_{A1}*R_A={\stackrel{\·}{U}}_{A1}\\ {\stackrel{\·}{I}}_{A3}*{j3\mathrm{\ωL}}_A+{\stackrel{\·}{I}}_{A3}/\left({j3\mathrm{\ωC}}_A\right)+{\stackrel{\·}{I}}_{A3}*R_A={\stackrel{\·}{U}}_{A3},\\ {\stackrel{\·}{I}}_{A5}*{j5\mathrm{\ωL}}_A+{\stackrel{\·}{I}}_{A5}/\left({j5\mathrm{\ωC}}_A\right)+{\stackrel{\·}{I}}_{A5}*R_A={\stackrel{\·}{U}}_{A5}\end{array}\right.$

Wherein, w is angular frequency, and j is the imaginary part of symbol; W=2f, wherein f=50Hz.

S3. draw as follows the initial oscillation f in power capacitor bank 4 loops _r0:

$f_{r0}=\frac{1}{2\mathrm{\π}\sqrt{L_A{C}_A}};$

S4. initialization is complete;

The running status of the power capacitor bank 4 of second step, monitoring objective current-limiting reactor:

S5. gather the fundametal compoment of monitoring phase bus 1 voltage third-harmonic component quintuple harmonics component gather the fundametal compoment of electric current at power capacitor bank 4 and the tie point of monitoring phase bus 1 third-harmonic component quintuple harmonics component

S6. to following solving equations, show that power capacitor bank 4 loops are current value and value:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{A1}^1*{\mathrm{j\ωL}}_A^1+{\stackrel{\·}{I}}_{A1}^1/\left({\mathrm{j\ωC}}_A^1\right)+{\stackrel{\·}{I}}_{A1}^1*R_A^1={\stackrel{\·}{U}}_{A1}^1\\ {\stackrel{\·}{I}}_{A3}^1*{j3\mathrm{\ωL}}_A^1+{\stackrel{\·}{I}}_{A3}^1/\left({j3\mathrm{\ωC}}_A^1\right)+{\stackrel{\·}{I}}_{A3}^1*R_A^1={\stackrel{\·}{U}}_{A3}^1,\\ {\stackrel{\·}{I}}_{A5}^1*{j5\mathrm{\ωL}}_A^1+{\stackrel{\·}{I}}_{A5}^1/\left({j5\mathrm{\ωC}}_A^1\right)+{\stackrel{\·}{I}}_{A5}^1*R_A^1={\stackrel{\·}{U}}_{A5}^1\end{array}\right.$

W=2f, wherein f=50Hz.

S7. draw as follows the current oscillation frequency f in power capacitor bank 4 loops _r ¹:

$f_r^1=\frac{1}{2\mathrm{\π}\sqrt{L_A^1{C}_A^1}};$

S8. be calculated as follows oscillation frequency rate of change l:

$\mathrm{\λ}=\frac{f_r^1}{f_{\mathrm{ro}}};$

S9. by l and the comparison of predetermined failure definite value, first send early warning and go to again S10 if l is greater than predetermined failure definite value, otherwise directly go to S10;

Wherein, definite method of predetermined failure definite value is as follows:

For benchmark phase bus, in power capacitor bank 4, contain M unit in parallel, each unit in parallel contains the capacitor of N series connection, and each capacitor contains m little unit in parallel, and each little unit in parallel contains the capacity cell of n series connection;

Default early-warning conditions is: early warning while puncturing k capacity cell;

Predetermined failure definite value is $\sqrt{1+\frac{k}{\mathrm{NMn}(m-k)+N(M-1)k}}.$

S10. judge whether to stop monitoring, go to if not S5 and continue monitoring, if monitoring finishes.

The major technique design of the present embodiment method is as follows:

The loop of living in power capacitor of current-limiting reactor is equivalent to RLC series circuit, then, by gathering fundametal compoment, third-harmonic component, the quintuple harmonics component of electric current and voltage, draws equivalent inductance L and equivalent capacity C, more further draw oscillation frequency; Then, the oscillation frequency while starting to put into operation taking power capacitor is benchmark, continues to monitor oscillation frequency and changes, when variation exceeds predetermined value alarm.

In order to make early warning more reliable, the present embodiment has also proposed definite method for predetermined failure definite value, and its principle is as follows:

If: in the power capacitor bank being connected with benchmark phase bus, contain M unit in parallel, each unit in parallel contains the capacitor of N series connection, and each capacitor contains m little unit in parallel, and each little unit in parallel contains the capacity cell of n series connection.

Default early-warning conditions is: early warning while puncturing k capacity cell.

: after k capacity cell punctures, the impedance variation of this capacitor doubly, and then make the impedance variation of fault phase capacitor group doubly, the capacitive reactance X of fault phase _c' be: $X_C^{\′}(1+\frac{k}{\mathrm{NMn}(m-k)+N(M-1)k})X_{C0},$ And its induction reactance is constant.

So time concussion frequency f _r' be:

$f_r^{\′}=f_0\sqrt{(1+\frac{k}{\mathrm{NMn}(m-k)+N(M-1)K})\frac{X_{C0}}{X_{L0}}}=\sqrt{1+\frac{k}{\mathrm{NMn}(m-k)+N(M-1)k}}{f}_{r0},$

Predetermined failure definite value is:

$\frac{f_r^{\′}}{f_{r0}}=\sqrt{1+\frac{k}{\mathrm{NMn}(m-k)+N(M-1)k}}.$

For example: N=1, M=2, n=2, m=8, k=1, predetermined failure definite value is:

$\frac{f_r^{\′}}{f_{r0}}=1.017;$

If k=2, predetermined failure definite value is:

$\frac{f_r^{\′}}{f_{r0}}=1.0377.$

The maintenance that the present embodiment method can be capacitor equipment provides more reliable early warning criterion, for the on-line monitoring of capacitor provides total solution, for the maintenance work of capacitor equipment has alleviated burden.

Claims (3)

1. for a realtime on-line monitoring method for the power capacitor bank running status of current-limiting reactor, it is characterized in that, comprise the following steps:

The first step, in the time that starting to put into operation, the power capacitor bank of target current-limiting reactor carries out initialization:

S1. gather described power capacitor bank and connect the fundametal compoment of a phase busbar voltage in three-phase bus. , third-harmonic component. , quintuple harmonics component. , and taking this mutually as monitoring phase; Gather the fundametal compoment of electric current at described power capacitor bank and the tie point of monitoring phase bus , third-harmonic component , quintuple harmonics component ;

S2. the loop of described power capacitor bank is equivalent to resistance R _a, reactance L _a, capacitor C _aseries circuit; To following solving equations, draw the L in described power capacitor bank loop _avalue and C _avalue:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{A1}*{\mathrm{j\ωL}}_A+{\stackrel{\·}{I}}_{A1}/\left({\mathrm{j\ωC}}_A\right)+{\stackrel{\·}{I}}_{A1}*R_A={\stackrel{\·}{U}}_{A1}\\ {\stackrel{\·}{I}}_{A3}*{j3\mathrm{\ωL}}_A+{\stackrel{\·}{I}}_{A3}/\left({j3\mathrm{\ωC}}_A\right)+{\stackrel{\·}{I}}_{A3}*R_A={\stackrel{\·}{U}}_{A3},\\ {\stackrel{\·}{I}}_{A5}*{j5\mathrm{\ωL}}_A+{\stackrel{\·}{I}}_{A5}/\left({j5\mathrm{\ωC}}_A\right)+{\stackrel{\·}{I}}_{A5}*R_A={\stackrel{\·}{U}}_{A5}\end{array}\right.$

Wherein, w is angular frequency, and j is the imaginary part of symbol;

S3. draw as follows the initial oscillation f in described power capacitor bank loop _r0:

$f_{r0}=\frac{1}{2\mathrm{\π}\sqrt{L_A{C}_A}};$

S4. initialization is complete;

The running status of the power capacitor bank of second step, monitoring objective current-limiting reactor:

S5. gather the fundametal compoment of monitoring phase busbar voltage , third-harmonic component quintuple harmonics component gather the fundametal compoment of electric current at described power capacitor bank and the tie point of monitoring phase bus third-harmonic component quintuple harmonics component

S6. to following solving equations, show that described power capacitor bank loop is current value and value:

$\left\{\begin{array}{c}{\stackrel{\·}{I}}_{A1}^1*{\mathrm{j\ωL}}_A^1+{\stackrel{\·}{I}}_{A1}^1/\left({\mathrm{j\ωC}}_A^1\right)+{\stackrel{\·}{I}}_{A1}^1*R_A^1={\stackrel{\·}{U}}_{A1}^1\\ {\stackrel{\·}{I}}_{A3}^1*{j3\mathrm{\ωL}}_A^1+{\stackrel{\·}{I}}_{A3}^1/\left({j3\mathrm{\ωC}}_A^1\right)+{\stackrel{\·}{I}}_{A3}^1*R_A^1={\stackrel{\·}{U}}_{A3}^1,\\ {\stackrel{\·}{I}}_{A5}^1*{j5\mathrm{\ωL}}_A^1+{\stackrel{\·}{I}}_{A5}^1/\left({j5\mathrm{\ωC}}_A^1\right)+{\stackrel{\·}{I}}_{A5}^1*R_A^1={\stackrel{\·}{U}}_{A5}^1\end{array}\right.$

S7. draw as follows the current oscillation frequency in described power capacitor bank loop

$f_r^1=\frac{1}{2\mathrm{\π}\sqrt{L_A^1{C}_A^1}};$

S8. be calculated as follows oscillation frequency rate of change l:

$\mathrm{\λ}=\frac{f_r^1}{f_{\mathrm{ro}}};$

S9. by l and the comparison of predetermined failure definite value, first send early warning and go to again S10 if l is greater than predetermined failure definite value, otherwise directly go to S10;

S10. judge whether to stop monitoring, go to if not S5 and continue monitoring, if monitoring finishes.

2. realtime on-line monitoring method according to claim 1, is characterized in that, in S9, definite method of described predetermined failure definite value is as follows:

For benchmark phase bus, in described power capacitor bank, contain M unit in parallel, each unit in parallel contains the capacitor of N series connection, and described each capacitor contains m little unit in parallel, and each little unit in parallel contains the capacity cell of n series connection;

Default early-warning conditions is: early warning while puncturing k capacity cell;

Described predetermined failure definite value is $\sqrt{1+\frac{k}{\mathrm{NMn}(m-k)+N(M-1)k}}.$

3. realtime on-line monitoring method according to claim 1, is characterized in that, in S2, S6, and the w=2f in system of equations, wherein f=50Hz.