CN205353339U - CVT state online test system - Google Patents

Abstract

The utility model discloses a CVT state online test system, including zero magnetic flow CT, standard PT, current collection device, a voltage acquisition device, the 2nd voltage acquisition device and central processing unit, the CVT that awaits measuring is connected to zero magnetic flow CT one end, other end junction current collection system, and electric current collection system still is connected to central processing unit, the CVT that awaits measuring is connected to a voltage acquisition device one end, and central processing unit is connected to the other end, the 2nd voltage acquisition device one end connection standard PT, central processing unit is connected to the other end, the utility model discloses can on -line monitoring CVT secondary angular difference, CVT secondary ratio, CVT main capacitance capacitance value and CVT dielectric loss parameter to can be through above -mentioned parameter synthesis aassessment CVT running state.

Description

A kind of CVT state Online Transaction Processing

Technical field

This utility model relates to equipment state online evaluation technical field, is specifically related to a kind of CVT state Online Transaction Processing.

Background technology

Current CVT is used widely, and has comparative advantage at 110～220kV, CVT consumption, not only in the limited selection of new website, often adopts CVT to replace PT, 330～500kV grade and all select to use CVT in the transformation of old station；The existing assessment to CVT adopts periodic detection, and this mode is difficult to find CVT accident defect of slowly development in running, it is impossible to finds in time, overhaul in time, and do not take into full account CVT virtual condition, causes unnecessary maintenance；And existing to CVT online evaluation only to the single parameter of CVT, be monitored such as dielectric loss, angular difference, ratio etc., do not pass through overall each parameter comprehensive assessment CVT state, cause assessment inaccuracy.

Utility model content

This utility model provides a kind of CVT state Online Transaction Processing.

The technical solution adopted in the utility model is: a kind of CVT state Online Transaction Processing, including Zero flux CT, standard PT, current collecting device, the first voltage collecting device, the second voltage collecting device and central processing unit；Described Zero flux CT one end connects CVT to be measured, and the other end connects current collecting device, and current collecting device is also connected to central processing unit；Described first voltage collecting device one end connects CVT to be measured, and the other end connects central processing unit；Described second voltage collecting device one end connection standard PT, the other end connects central processing unit.

Further, system during synchronization pair is also included；During synchronization pair, system one end connects central processing unit, and the other end connects the first voltage collecting device and the second voltage collecting device respectively.

The beneficial effects of the utility model:

(1) this utility model can detect its operational factor in CVT running, finds fault in time；

(2) this utility model can on-line checking multiple operational factor such as dielectric loss, angular difference, ratio etc.；

(3) this utility model can according to CVT parameter online evaluation CVT running status.

Accompanying drawing explanation

Fig. 1 is this utility model structural representation.

Fig. 2 is this utility model flow chart.

Fig. 3 is schematic diagram after this utility model three-phase data vectorization.

Fig. 4 is this utility model three-phase data vector analysis schematic diagram.

Detailed description of the invention

Below in conjunction with the drawings and specific embodiments, this utility model is described further.

A kind of CVT state Online Transaction Processing, including Zero flux CT, standard PT, current collecting device, the first voltage collecting device, the second voltage collecting device and central processing unit；Described Zero flux CT one end connects CVT to be measured, and the other end connects current collecting device, and current collecting device is also connected to central processing unit；Described first voltage collecting device one end connects CVT to be measured, and the other end connects central processing unit；Described second voltage collecting device one end connection standard PT, the other end connects central processing unit；Gather Leakage Current by Zero flux CT, an earth current is converted to small-signal current, and by current collecting device, small area analysis signal is converted to digital quantity signal and includes current amplitude, power frequency and current phase；Gather CVT secondary voltage by the first voltage collecting device, and voltage dress is changed to digital quantity signal includes voltage magnitude, electric voltage frequency and voltage-phase；Gather standard PT secondary voltage by the second voltage collecting device, and convert voltages into digital quantity signal and include voltage magnitude, electric voltage frequency and voltage-phase.

Further, system during synchronization pair is also included；During synchronization pair, system one end connects central processing unit, and the other end is simultaneously connected with the first voltage collecting device and the second voltage collecting device；Voltage signal system synchronization when synchronization pair gathers, it is ensured that the synchronicity of signals collecting.

The Dielectric loss angle δ of electric capacity is the complementary angle of Leakage Current I and standard PT secondary voltage U angle；Phase angle according to Leakage Current Yu standard PT secondary voltage can obtain the dielectric loss value tan δ of CVT main capacitance.

Can obtain according to Circuit Theorem:

$\stackrel{\·}{I}=j\mathrm{\ω}C\stackrel{\·}{U}+\frac{\stackrel{\·}{U}}{R}=J\left|I\right|\frac{1}{\sqrt{1+{\tan }^2\mathrm{\δ}}}+\left|I\right|\frac{\tan \mathrm{\δ}}{\sqrt{1+{\tan }^2\mathrm{\δ}}}$

In formula:For Leakage Current value, [I] is Leakage Current virtual value, and ω is system angle frequency, and C is CVT main capacitance capacitance, and R is equivalent capacity leak resistance,For the standard PT system voltage recorded；

CVT main capacitance capacitance can be derived from by above formula:

$C=\frac{\left|I\right|}{\mathrm{\ω}*U*\sqrt{1+{\tan }^2\mathrm{\δ}}}=\frac{\left|I\right|}{2\mathrm{\π}f*U*\sqrt{1+{\tan }^2\mathrm{\δ}}}$

CVT secondary voltage ratio is the ratio of the CVT secondary voltage amplitude with standard PT secondary voltage；CVT secondary voltage angular difference is the phase place ratio of CVT secondary voltage and standard PT secondary voltage.

Leakage Current, CVT secondary voltage and standard PT secondary voltage is recorded according to a kind of CVT state Online Transaction Processing, sending these parameters to central processing unit, above-mentioned parameter is calculated obtaining CVT secondary voltage angular difference, CVT secondary voltage ratio, CVT main capacitance capacitance and CVT main capacitance dielectric loss parameter by central processing unit.

A kind of CVT state online evaluation method, comprises the following steps successively:

Parameter acquiring: obtain CVT secondary voltage angular difference, CVT secondary voltage ratio, CVT main capacitance capacitance and CVT main capacitance dielectric loss value；

Judge whether data exceed threshold value；

Data weighting: when CVT main capacitance capacitance and CVT dielectric loss value exceed alarm threshold, adding its variable quantity increases its weight, and weight is self；CVT main capacitance capacitance and CVT main capacitance dielectric loss value are 1 not less than the data weighting of threshold value；CVT secondary voltage angular difference and CVT secondary voltage ratio, data rights refetches certain value；

Qualitative assessment: data are carried out quantification according to experimental data, it is determined that qualitative assessment value and assessed value phase place；

Valuation is analyzed: judge whether normally according to the size of quantitative values, confirms fault phase according to assessed value phase place.

Further, adopt data vector than phase algorithm before qualitative assessment；Out-phase can be got rid of and disturb the impact brought.

Further, the parameter exceeding threshold value is passed through data vector than phase algorithm, then jointly carries out qualitative assessment with the data being weighted calculating；The interference that more further removal system brings.

Further, described data weighting algorithm is as follows:

The parameter measured, with alarm threshold for benchmark, takes its relative value；If basic parameter integrates as A={a1, a2, a3 ... an}, by therein > ask for average with remaining value after the value of 1 is squared；When parameter unit number is more than alarm threshold, adding its variable quantity increases its weight, and namely weight is self.

Further, the data weighting of described CVT secondary voltage angular difference and CVT secondary voltage ratio is 0.8.

As follows according to the specific algorithm getting rid of out-phase interference than phase algorithm:

According to the CVT secondary voltage angular difference obtained, CVT secondary voltage ratio, CVT main capacitance capacitance and CVT main capacitance dielectric loss parameter, the voltage spaces fixing for electrical network obtains data below:

Wherein A phase is a certain voltage value, and B phase and A phase have a fixed voltage interval, also has identical voltage spaces between B phase and C phase.

Above-mentioned data are represented by respective symbol respectively and obtain:

By above-mentioned data as it is shown on figure 3, plane to be divided into three pieces of regions: respectively A phase region, B phase region and C phase region；The triphase parameter recorded is carried out following conversion, for CVT dielectric loss value:

Tan δ ∑=tan δ a+tab δ b*e^j240+tabδc*e^j120

If dielectric loss value is caused by system, then tan δ a=tan δ b=tan δ c, tan δ ∑=0；

If wherein a phase dielectric loss value becomes big, and the change of other biphase dielectric loss value is little, i.e. tan δ a>tan δ b=tan δ c, then tan δ ∑ is certain value, and tan δ ∑ phase angle-60<arg (tan δ ∑)<60, namely fall within A district, as shown in the figure, thus reaching to get rid of the purpose of out-phase interference, other parameter is also adopted by identical method and processes.

Appraisal procedure adopts matlab language to realize:

Detailed process is as follows:

Above-mentioned flow process matlab language is accomplished by

Wherein Matrix C VTA (in matrix, all elements is the relative value to alarm threshold):

$CVTA=\left[\begin{array}{ccc}\tan \mathrm{\&delta;}a& tan\mathrm{\&delta;}b& tan\mathrm{\&delta;}c\\ Ca& Cb& Cc\\ \mathrm{\&theta;}a& \mathrm{\&theta;}b& \mathrm{\&theta;}c\\ Rata& Ratb& Ratc\end{array}\right]$

Wherein matrix dCVT (in matrix, all elements is the relative value to alarm threshold)

$dCVTA=\left[\begin{array}{ccc}d\tan \mathrm{\&delta;}a& d\tan \mathrm{\&delta;}b& d\tan \mathrm{\&delta;}c\\ dCa& dCb& dCc\\ d\mathrm{\&theta;}a& d\mathrm{\&theta;}b& d\mathrm{\&theta;}c\\ dRata& dRatb& dRatc\end{array}\right]$

Ratio phase matrix SelPha:

Weighting matrix Wei:

$Wei=\left[\begin{array}{cc}\begin{array}{cc}1& 0\\ 0& 1\end{array}& 0\\ 0& \begin{array}{cc}0.8& 0\\ 0& 0.8\end{array}\end{array}\right]$

A=cels (4,3)；%

B=cels (4,3)；

Eval=cels (4,3)；

C=cels (4,3)；

D=cels (4,3)；

A=CVTA；

A (A > 1)=0；%% will be greater than the element zero setting of reference value

B=CVTA-A；%% proposes the element more than reference value

B=B.^2；%% will be greater than the element square of reference value

C=A+B；In %% matrix, value more than 1 carries out square

C=Wei*C%% is to wherein angular difference and ratio weighting

C=C*SelPha%% compares phase

Eval=mean (C (:)) %% all elements meansigma methods

D=CVTA；

D (D≤1)=0；%% is by the element zero setting less than or equal to reference value

I=all (D, 2)；

D (I :)=[]；Remove null value row, generate new matrix；

D=D*SelPha%% compares phase

Eval=Eval+mean (D (:)) %% assesses quantitative values

Evalue=abs (Eval)；

Pha=angle (Eval)；

Whether IfEvalue > Ewarm%% exceedes setting value

Warming=1%% exceedes alarming value

Else

Warming=0

IfPha>=-π/3&&Pha<π/3%% fault is separate

Ph=" A "；

ElseIfPha>=π/3&&Pha<π

Ph=" C "；

Else

Ph=" B "；

This utility model can bis-angular differences of on-line monitoring CVT, bis-ratios of CVT, CVT main capacitance capacitance and CVT dielectric loss parameter, and above-mentioned parameter comprehensive assessment CVT running status can be passed through.

Claims (2)

1. a CVT state Online Transaction Processing, it is characterised in that: include Zero flux CT, standard PT, current collecting device, the first voltage collecting device, the second voltage collecting device and central processing unit；Described Zero flux CT one end connects CVT to be measured, and the other end connects current collecting device, and current collecting device is also connected to central processing unit；Described first voltage collecting device one end connects CVT to be measured, and the other end connects central processing unit；Described second voltage collecting device one end connection standard PT, the other end connects central processing unit.

2. a kind of CVT state Online Transaction Processing according to claim 1, it is characterised in that: also include system during synchronization pair；During synchronization pair, system one end connects central processing unit, and the other end is simultaneously connected with the first voltage collecting device and the second voltage collecting device.