Summary of the invention
The invention provides a kind of CVT state Online Transaction Processing and online evaluation method.
The technical solution used in the present invention is: a kind of CVT state Online Transaction Processing, comprises Zero flux CT, standard P T, 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 when also including synchronous pair; When synchronous pair, system one end connects central processing unit, and the other end connects the first voltage collecting device and the second voltage collecting device simultaneously.
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; The data weighting that CVT main capacitance capacitance and CVT main capacitance dielectric loss value do not exceed threshold value is 1; CVT secondary voltage angular difference and CVT secondary voltage ratio, data rights refetches certain value;
Qualitative assessment: experimentally data are carried out quantification by data, determines 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.
Further, the parameter exceeding threshold value by than phase algorithm by data vector, then jointly carry out qualitative assessment with the data through weighted calculation.
Further, described data weighting algorithm is as follows:
The parameter measured is benchmark with alarm threshold, gets its relative value; If basic parameter integrates as A={a1, a2, a3 ... an}, asks for average with remaining value after squared for the value of >1 wherein; When parameter unit number is greater 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.
Beneficial effect of the present invention:
(1) the present invention can detect its operational factor, Timeliness coverage fault in CVT operational process;
(2) the present invention can on-line checkingi multiple operational factor as dielectric loss, angular difference, ratio etc.;
(3) the present invention can according to CVT parameter online evaluation CVT running status.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention will be further described.
A kind of CVT state Online Transaction Processing, comprises Zero flux CT, standard P T, 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, a ground current is converted to small-signal current, and by current collecting device, small area analysis signal is converted to digital quantity signal and comprises 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 comprises voltage magnitude, electric voltage frequency and voltage-phase; Gather standard P T secondary voltage by the second voltage collecting device, and be that digital quantity signal comprises voltage magnitude, electric voltage frequency and voltage-phase by voltage transitions.
Further, system when also including synchronous pair; When synchronous pair, system one end connects central processing unit, and the other end connects the first voltage collecting device and the second voltage collecting device simultaneously; Voltage signal system synchronization through synchronous pair time gathers, and ensures the synchronism of signals collecting.
The Dielectric loss angle δ of electric capacity is the complementary angle of Leakage Current I and standard P T secondary voltage U angle; The dielectric loss value tan δ of CVT main capacitance can be obtained according to the phasing degree of Leakage Current and standard P T secondary voltage.
Can obtain according to Circuit Theorem:
$\stackrel{\·}{I}=j\mathrm{\ω}C\stackrel{\·}{U}+\frac{\stackrel{\·}{U}}{R}=j\left|I\right|\frac{1}{\sqrt{1+{\mathrm{tan}}^{2}\mathrm{\δ}}}+\left|I\right|\frac{\mathrm{tan}\mathrm{\δ}}{\sqrt{1+{\mathrm{tan}}^{2}\mathrm{\δ}}}$
In formula:
for Leakage Current value, | I| is Leakage Current effective value, and ω is system angle frequency, and C is CVT main capacitance capacitance, and R is equivalent capacity leak resistance,
for the system voltage that standard P T records;
Can be derived by above formula and draw CVT main capacitance capacitance:
$C=\frac{\left|I\right|}{\mathrm{\ω}*U*\sqrt{1+{\mathrm{tan}}^{2}\mathrm{\δ}}}=\frac{\left|I\right|}{2\mathrm{\π}f*U*\sqrt{1+{\mathrm{tan}}^{2}\mathrm{\δ}}}$
CVT secondary voltage ratio is CVT secondary voltage and the ratio of the amplitude of standard P T secondary voltage; CVT secondary voltage angular difference is CVT secondary voltage and the phase place ratio of standard P T secondary voltage.
Leakage Current, CVT secondary voltage and standard P T secondary voltage is recorded according to a kind of CVT state Online Transaction Processing, these parameters are sent to central processing unit, and central processing unit calculates CVT secondary voltage angular difference, CVT secondary voltage ratio, CVT main capacitance capacitance and CVT main capacitance dielectric loss parameter to above-mentioned parameter.
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; The data weighting that CVT main capacitance capacitance and CVT main capacitance dielectric loss value do not exceed threshold value is 1; CVT secondary voltage angular difference and CVT secondary voltage ratio, data rights refetches certain value;
Qualitative assessment: experimentally data are carried out quantification by data, determines 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 by than phase algorithm by data vector, then jointly carry out qualitative assessment with the data through weighted calculation; The interference that more further removal system brings.
Further, described data weighting algorithm is as follows:
The parameter measured is benchmark with alarm threshold, gets its relative value; If basic parameter integrates as A={a1, a2, a3 ... an}, asks for average with remaining value after squared for the value of >1 wherein; When parameter unit number is greater 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 following data:
Wherein A phase is a certain voltage value, and B phase and A phase have a fixed voltage interval, also have 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 shown in Figure 3, plane is divided into three pieces of regions: be 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:
tanδΣ＝tanδa+tanδb*e
^{j240}+tanδc*e
^{j120}
If dielectric loss value is caused by system, then tan δ a=tan δ b=tan δ c, tan δ Σ=0;
If wherein a phase dielectric loss value becomes large, and the change of other two-phase dielectric loss value is little, i.e. tan δ a>tan δ b=tan δ c, then tan δ Σ is certain value, and tan δ Σ phase angle-60<arg (tan δ Σ) <60, namely fall within A district, as shown in the figure, thus reaching the object getting rid of out-phase interference, other parameter also adopts identical method to process.
Appraisal procedure adopts matlab language to realize:
Detailed process is as follows:
Above-mentioned flow process matlab language realizes as follows:
Wherein Matrix C VTA (in matrix, all elements is the relative value to alarm threshold):
$CVTA=\left[\begin{array}{ccc}tan\mathrm{\δ}a& tan\mathrm{\δ}b& tan\mathrm{\δ}c\\ Ca& Cb& Cc\\ {\mathrm{\θ}}_{a}& {\mathrm{\θ}}_{b}& {\mathrm{\θ}}_{c}\\ Rata& Ratb& Ratc\end{array}\right]$
Wherein matrix dCVT (in matrix, all elements is the relative value to alarm threshold)
$dCVTA=\left[\begin{array}{ccc}d\mathrm{tan}\mathrm{\δ}a& d\mathrm{tan}\mathrm{\δ}b& d\mathrm{tan}\mathrm{\δ}c\\ dCa& dCb& dCc\\ {\mathrm{d\θ}}_{a}& {\mathrm{d\θ}}_{b}& {\mathrm{d\θ}}_{c}\\ dRata& dRatb& dRatc\end{array}\right]$
Than phase matrix SelPha:
$SelPha=\left[\begin{array}{ccc}1& & \\ & {e}^{j240}& \\ & & {e}^{j120}\end{array}\right]$
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 being greater than reference value
B=B.^2; %% will be greater than the element square of reference value
C=A+B; The value being greater than 1 in %% matrix is carried out square
C=Wei*C%% is to wherein angular difference and ratio weighting
C=C*SelPha%% compares phase
Eval=mean (C (:)) %% all elements mean value
D＝CVTA；
D (D<=1)=0; %% will be less than or equal to the element zero setting of 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”；
The present invention can on-line monitoring CVT bis-angular differences, CVT bis-ratios, CVT main capacitance capacitance and CVT dielectric loss parameter, and can pass through above-mentioned parameter comprehensive assessment CVT running status.