CN106129975A - A kind of differential protecting method based on active power fault component criterion - Google Patents

Abstract

The invention discloses a kind of differential protecting method based on active power fault component criterion, comprise the following steps: obtain whole voltage x current synchronously sampled datas that in differential protection range boundary, each chopper is relevant；By whole voltage x current sampling numbers according to changing into perunit value data according to power system perunit value conversion method, calculate, according to perunit value data, the power failure component samples point data that each chopper is relevant；Ask for the integrated value of the active power fault component sampled point obtained, determine fault component working value and the brake value of differential protection active power；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 breaks down, and sending trip signal to the intelligent terminal of every side chopper.

Description

A kind of differential protecting method based on active power fault component criterion

Technical field

The present invention relates to a kind of differential protecting method based on active power fault component criterion.

Background technology

The maturation method of current differential protection mainly has: 1) phasor value current differential protection；2) sampled value current differential is protected Protect；3) fault component current differential protection.It is tight that phasor value current differential protection exercise speed not enough is difficult to quickly respond inside soon Weight fault, and to the TA occurred during external area error is saturated and transformer excitation flow is required to assistant criteria and can avoid Malfunction.Sampling value differential protection generally uses the most continuous R the sampling of repeatedly method of discrimination have S time in differentiating and meet above Operating criterion just output action signal, the saturated situation of TA occurred for external area error and transformer excitation flow all have necessarily to be kept away Exempt from malfunction ability.Fault component current differential protection on reduce protected circuit capacitance current to affect effectiveness higher.

But there is following defect in the differential protecting method of these maturations: is all based on the magnitude of current and realizes, to on-load voltage regulation The out-of-balance current that load tap changer causes after adjusting does not has adaptive ability, can only advise by raising definite value threshold Keep away, this reduces the susceptiveness of differential protection, thus affect differential protection scene operation characteristic and effect；The purest magnitude of current Naturally containing reactive power in criterion is main excitation surge current impact, differential guarantor of shoving Transformer Close under non-faulting state Protect naturally occurring considerable influence.

Summary of the invention

The present invention is to solve the problems referred to above, it is proposed that a kind of differential protection side based on active power fault component criterion Method, this method can reduce the shadow to differential protection of the excitation surge current based on reactive power by introducing active power criterion Ring, the distributed electrical capacitance current of the UHV transmission line shadow to differential protection can be reduced by introducing active power criterion Ring, cause difference by TA is saturated when at least satisfied two the equation discriminant approaches of R point can effectively reduce external area error in S point Dynamic false protection probability.

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

A kind of differential protecting method based on active power fault 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) ask for the integrated value of the active power fault component sampled point obtained, determine the event of differential protection active power Barrier component working value and brake value；

(4) set the fault component threshold of differential protection active power, set differential protection operating space with this and differentiate, if Meet operating space discrimination standard, assert that primary equipment breaks down, and send tripping operation life to the intelligent terminal of every side chopper Order.

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 breaks down, and sends trip signal to the intelligent terminal of every side chopper.

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

The invention have the benefit that

(1) present invention solve existing differential protecting method exist based on the magnitude of current realize, to on-load voltage regulation transformation The out-of-balance current caused after device tap_changing does not has adaptive ability, can only evade by raising definite value threshold, this Just reduce the susceptiveness of differential protection, thus the problem affecting differential protection scene operation characteristic and effect；

(2) present invention can reduce the excitation surge current based on reactive power to differential guarantor by introducing active power criterion The impact protected, can reduce the distributed electrical capacitance current of UHV transmission line to differential protection by introducing active power criterion Impact, by S point at least R point meet when two equation discriminant approaches can effectively reduce external area error that TA is saturated makes Become differential protection malfunction probability.

Detailed description of the invention:

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

A kind of differential protecting method based on active power fault 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；

U1 (k), u2 (k) voltage sample point initial data；

I1 (k), i2 (k) current sample point initial data；

U1e, u2e are for calculating the voltage secondary reference value of perunit value；

I1e, i2e are for 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,

Δp_d=| | 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)||

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

Δp_dDifferential protection active power fault component working value sampled point；

Δp_rDifferential protection active power fault component braking value 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,

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

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

ΣΔp_dDifferential protection active power fault component working value；

ΣΔp_rDifferential protection active power fault component braking 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 Meeting two equation situations, the primary equipment regarded as in differential protection scope district breaks down, and to every side chopper Intelligent terminal sends trip signal, wherein,

$\left\{\begin{array}{c}{\mathrm{\Σ\Δp}}_d>{\mathrm{\Δp}}_{qd}\\ {\mathrm{\Σ\Δp}}_d>{\mathrm{\Σ\Δp}}_r\×K_p\end{array}\right.$

ΣΔp_dDifferential protection active power fault component working value；

ΣΔp_rDifferential protection active power fault component braking value；

Δp_qdDifferential protection active power fault component threshold；

K_pDifferential 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.

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. a differential protecting method based on active power fault 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) ask for the integrated value of the active power fault component sampled point obtained, determine that the fault of differential protection active power is divided Amount working value and brake value；

(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 breaks down, and sends trip signal to the intelligent terminal of every side chopper.

A kind of differential protecting method based on active power fault 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 differential protecting method based on active power fault 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 differential protecting method based on active power fault 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 differential protecting method based on active power fault 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 breaks down, and sends trip signal to the intelligent terminal of every side chopper.