CN106058810A - Excitation inrush current identification method based on power fault component criterion - Google Patents

Abstract

The invention discloses an excitation inrush current identification method based on a power fault component criterion. The method comprises the following steps: obtaining all voltage current synchronous sampling data correlated with each breaker on the boundary of a differential protection scope; converting all the voltage current sampling point data into per unit value data according to a power system per unit value conversion method, and according to the per unit value data, calculating power fault component sampling point data correlated with each breaker; solving integral values of obtained fault component sampling points of active power and reactive power; and setting a fault component threshold of differential protection active power, based on this, setting differential protection motion area determining, and if a motion area determining standard is satisfied, consuming that a fault does not occur in primary equipment yet excitation inrush currents exist and emitting excitation inrush current blocking signals to differential protection logic. According to the invention, when a transformer is closed due to a quite severe internal fault, the excitation inrush current criterion fails automatically and differential protection is not blocked, such that rapid tripping is realized.

Description

A kind of excitation flow recognition method based on power failure component criterion

Technical field

The present invention relates to a kind of excitation flow recognition method based on power failure component criterion.

Background technology

Current excitation surge current knows method for distinguishing mainly to be had: 1) second order harmonics principle；2) interrupted angle principle；3) waveform symmetry is former Reason；4) virtual third harmonic principle；5) theory of wavelet transformation.These methods have certain effect for excitation surge current identification.But Be these methods be all with current signal and waveform for according to differentiating, not utilizing excitation surge current mainly by reactive power structure The factor become.

Summary of the invention

The present invention is to solve the problems referred to above, it is proposed that a kind of excitation surge current identification side based on power failure component criterion Method, this method utilizes the factor that excitation surge current is mainly made up of reactive power, by reactive power fault component and active power Fault component accounting identification non-faulting state excitation surge current, it is possible to promote the non-faulting excitation surge current recognition effect of differential protection, There is higher sensitivity and reliability.

To achieve these goals, the present invention adopts the following technical scheme that

A kind of excitation flow recognition method based on power failure component criterion, comprises the following steps:

(1) whole voltage x current synchronously sampled datas that in differential protection range boundary, each chopper is relevant are obtained；

(2) by whole voltage x current sampling numbers according to changing into perunit value number according to power system perunit value conversion method According to, calculate, according to perunit value data, the power failure component samples point data that each chopper is relevant；

(3) integrated value of the fault component sampled point of the active power of acquisition, reactive power is asked for；

(4) set the fault component threshold of differential protection active power, set differential protection operating space with this and differentiate, if Meeting operating space discrimination standard, identification primary equipment does not breaks down but there is excitation surge current, and sends out to differential protection logic Go out excitation surge current block signal.

In described step (1), voltage x current synchronously sampled data is all by differential protection synchronized sampling or by inserting Value synchronization process obtains.

In described step (1), voltage x current synchronously sampled data is by being respectively connected to different combining unit, closing difference And unit realizes synchronized sampling or asynchronous-sampling data is obtained by interpolation algorithm the synchronously sampled data of whole analog quantity.

In described step (1), all senses of current are all to point to differential protection scope outside differential protection range boundary It it is positive direction or all to point in differential protection range boundary as positive direction outside differential protection range boundary in border.

In described step (4), the condition of area judging includes following:

(1) differential protection active power fault component working value is more than the differential protection active power fault component door set Threshold value；

(2) differential protection active power fault component braking value is more than differential protection slope definite value and differential protection wattful power The product of rate fault component working value；

If at least R point meets the most satisfied two equation situations in S point continuously, regard as differential protection scope district Interior primary equipment does not breaks down but there is excitation surge current, and sends excitation surge current block signal to differential protection logic.

The invention have the benefit that

(1) present invention utilizes the factor that excitation surge current is mainly made up of reactive power, by reactive power fault component with Active power fault component accounting identification non-faulting state excitation surge current, it is possible to the non-faulting excitation surge current promoting differential protection is known Other effect, has higher sensitivity and reliability；

(2) present invention this excitation surge current criterion when Transformer Close is in more serious internal fault ceases to be in force automatically and will not be formed Locking to differential protection, thus realize fast trip.

Detailed description of the invention:

Below in conjunction with embodiment, the invention will be further described.

The excitation flow recognition method of a kind of power failure component criterion, is characterized in that, comprise the following steps:

1) whole voltage x current synchronously sampled datas that in differential protection range boundary, each chopper is relevant are obtained；

2) whole voltage x current sampling numbers are changed into perunit value data according to according to power system perunit value conversion method:

u'_1(k)=u_1(k)/U_1e

u'_2(k)=u_2(k)/U_2e

i'_1(k)=i_1(k)/I_1e

i'_2(k)=i_1(k)/I_2e

u'_1(k)、u'_2(k)Voltage sample point perunit value data；

i'_1(k)、i'_2(k)Current sample point perunit value data；

u_1(k)、u_2(k)Voltage sample point initial data；

i_1(k)、i_2(k)Current sample point initial data；

u_1e、u_2eFor calculating the voltage secondary reference value of perunit value；

i_1e、i_2eFor calculating the electric current secondary reference value of perunit value；

3) calculate, according to synchronized sampling voltage x current perunit value data, the power failure component samples point that each chopper is relevant Data, wherein,

Δ p=| | u '_1(k)i′_1(k)+u′_2(k)i′_2(k)|-|u′_1(k-N)i′_1(k-N)+u′_2(k-N)i′_2(k-N)||

Δ q=| | u '_1(k)i′_1(k-N/4)+u′_2(k)i′_2((k-N/4))|-|u′_1(k-N)i′_1((k-5N/4))+u′_2(k-N)i′_2((k-5N/4))| |

Δ p differential protection active power fault component sampled point；

Δ q differential protection reactive power fault component sampled point；

N differential protection every cycle sampling number；

4) to step 3) the middle active power fault component sampling number obtained is according to being integrated, wherein,

$\mathrm{\Σ}\mathrm{\Δ}p=\underset{k=1}{\overset{N}{\Σ}}\left|\right|{u^{\′}}_{1\left(k\right)}{i^{\′}}_{1\left(k\right)}+{u^{\′}}_{2\left(k\right)}{i^{\′}}_{2\left(k\right)}|-|{u^{\′}}_{1(k-N)}{i^{\′}}_{1(k-N)}+{u^{\′}}_{2(k-N)}{i^{\′}}_{2(k-N)}\left|\right|$

$\mathrm{\Σ}\mathrm{\Δ}q=\underset{k=1}{\overset{N}{\Σ}}\left|\right|{u^{\′}}_{1\left(k\right)}{i^{\′}}_{1(k-N/4)}+{u^{\′}}_{2\left(k\right)}{i^{\′}}_{2(k-N/4)}|-|{u^{\′}}_{1(k-N)}{i^{\′}}_{1(k-5N/4)}+{u^{\′}}_{2(k-N)}{i^{\′}}_{2(k-5N/4)}\left|\right|$

Σ Δ p differential protection active power fault component integrated value；

Σ Δ q differential protection reactive power fault component integrated value；

N differential protection every cycle sampling number；

5) carry out differential protection operating space differentiation according to below equation, in continuous S point at least R point meet all Meet two equation situations, regard as the transformator generation excitation surge current in differential protection scope district, and patrol to differential protection Collect and send excitation surge current block signal.Wherein,

$\left\{\begin{array}{c}\mathrm{\Σ}\mathrm{\Δ}p>{\mathrm{\Δp}}_{qd}\\ \mathrm{\Σ}\mathrm{\Δ}q>\mathrm{\Σ}\mathrm{\Δ}p\×K_q\end{array}\right.$

Σ Δ p differential protection active power fault component integrated value；

Σ Δ q differential protection reactive power fault component integrated value；

Δp_qdDifferential protection active power fault component threshold；

K_qDifferential protection slope definite value.

Described step 1) in, voltage x current synchronously sampled data both can all access same protection device or merge single In unit, synchronized sampling obtains, it is also possible to by being respectively connected to different combining unit, more different combining units being realized synchronized sampling Or asynchronous-sampling data are obtained by certain interpolation algorithm the synchronously sampled data of whole analog quantitys.

Described step 1) in, all senses of current are all to point to differential protection scope limit outside differential protection range boundary It it is positive direction or all to point in differential protection range boundary as positive direction outside differential protection range boundary in boundary.

The setting of R and S is arranged with experience as the case may be.

Although the above-mentioned detailed description of the invention to the present invention is described, but not limit to scope System, one of ordinary skill in the art should be understood that on the basis of technical scheme, and those skilled in the art need not pay Go out various amendments or deformation that creative work can make still within protection scope of the present invention.

Claims (5)

1. an excitation flow recognition method based on power failure component criterion, is characterized in that: comprise the following steps:

(1) whole voltage x current synchronously sampled datas that in differential protection range boundary, each chopper is relevant are obtained；

(2) by whole voltage x current sampling numbers according to changing into perunit value data, root according to power system perunit value conversion method The power failure component samples point data that each chopper is relevant is calculated according to perunit value data；

(3) integrated value of the fault component sampled point of the active power of acquisition, reactive power is asked for；

(4) set the fault component threshold of differential protection active power, set differential protection operating space with this and differentiate, if meeting Operating space discrimination standard, assert that primary equipment does not breaks down but there is excitation surge current, and sends to differential protection logic and encourage Magnetic shoves block signal.

A kind of excitation flow recognition method based on power failure component criterion, is characterized in that: institute Stating in step (1), voltage x current synchronously sampled data is all by differential protection synchronized sampling or by interpolation synchronization process Obtain.

A kind of excitation flow recognition method based on power failure component criterion, is characterized in that: institute Stating in step (1), voltage x current synchronously sampled data is by being respectively connected to different combining unit, realizing different combining units Synchronized sampling or asynchronous-sampling data are obtained by interpolation algorithm the synchronously sampled data of whole analog quantity.

A kind of excitation flow recognition method based on power failure component criterion, is characterized in that: institute Stating in step (1), all senses of current are all to point in differential protection range boundary as just outside differential protection range boundary Direction or all to point in differential protection range boundary as positive direction outside differential protection range boundary.

A kind of excitation flow recognition method based on power failure component criterion, is characterized in that: institute Stating in step (4), the condition of area judging includes following:

(1) differential protection active power fault component working value is more than the differential protection active power fault component threshold set Value；

(2) differential protection active power fault component braking value is more than differential protection slope definite value and the event of differential protection active power The product of barrier component working value；

If in S point, at least R point meets the most satisfied two equation situations continuously, regard as in differential protection scope district Primary equipment does not breaks down but there is excitation surge current, and sends excitation surge current block signal to differential protection logic.