CN103076541A - Fault distance measuring method and fault distance measuring module for intelligent power grid power distribution line - Google Patents

Abstract

The invention relates to a fault distance measuring method and a fault distance measuring module for an intelligent power grid power distribution line. A double-circuit line is used for carrying out distance measurement as a single-circuit line; and the distance measurement of any fault on double circuits is subjected to distance measurement calculation by adopting a current sampling value of the double-circuit line and a bus voltage sampling value. According to the fault distance measuring method and the fault distance measuring module for the intelligent power grid power distribution line disclosed by the invention, a fault point voltage deduction equation adopts a negative sequence modulus and a variable quantity positive sequence modulus and influences on distance measuring precision, caused by the fact that parameters of a zero-sequence circuit of the power distribution line are inaccurate, can be effectively eliminated.

Description

The fault distance-finding method and the fault localization module that are used for the intelligent grid transmission line of electricity

Technical field

The present invention relates to a kind of fault distance-finding method for the intelligent grid transmission line of electricity.

Background technology

Intelligent grid transformer station is divided into process layer, wall and station level at present, and the voltage at each interval of primary system, electric current double sampling value transfer to client by process-level network, and transmission protocol is the IEC61850-9-2SV message protocol.Any line protective devices can also obtain current sampling data and the busbar voltage sampled value at other intervals except this spacing current sampled value.

Line protection is adopted more and more based on the longitudinal differential protection of optical-fibre channel or longitudinal distance protection, voltage, current sampling data that the arbitrary end protective device of transmission line of electricity all can Real-time Obtaining circuit offside.

Along with land resource is more and more rare, the transmission of electricity corridor is the parallel lines on same tower double back transmission line more at present, affected by the zero-sequence mutual inductance of double loop when on the transmission line of electricity earth fault occuring, and is difficult to accurately calculate the trouble spot particular location.When the double loop cross line fault occurs, limit by present fault localization principle and also be difficult to calculate accurately position of failure point in addition.

Summary of the invention

The purpose of this invention is to provide a kind of fault distance-finding method for the intelligent grid transmission line of electricity and fault localization module, limit and also be difficult to calculate the accurately problem of position of failure point in order to solve present fault localization principle.

For achieving the above object, the solution of the present invention comprises:

A kind of fault distance-finding method for the intelligent grid transmission line of electricity, step is as follows:

1) for the protection of transmission line of electricity both sides, after the protection action tripping operation of either side, gathers the voltage and current of both sides; Note wherein side protection is L with the trouble spot distance, and this side is this side, and opposite side is offside, and line length is L _Set

2) calculate respectively voltage sample value and the resultant current sampled value of both sides, the voltage sample value of every side is got this side bus PT voltage sample value, and every side resultant current sampled value is the current instantaneous value sum of this circuit Yu the adjacent lines of this side;

3) utilize step 2) voltage sample value and the resultant current sampled value of the both sides that obtain, calculating book side voltage vector value

The current vector value

The voltage vector value of offside

The current vector value

Substitution fault point voltage magnitude calculation equation $\begin{array}{c}\left|{\stackrel{.}{U}}_{\mathrm{mf}}\right|=|{\stackrel{.}{U}}_m-{\stackrel{.}{I}}_m\×\stackrel{.}{Z}\×L|\\ \left|{\stackrel{.}{U}}_{\mathrm{nf}}\right|=|{\stackrel{.}{U}}_n-{\stackrel{.}{I}}_n\×\stackrel{.}{Z}\×(L_{\mathrm{set}}-L)|\end{array},$ In the equation

With

Be a side voltage and current vector value,

With Be opposite side voltage and current vector value.

Be the circuit positive sequence impedance; Order | U _Mf| with | U _Mf| equate, resolve the trouble spot apart from the length L of this side protection.

After the protection action tripping operation of either side, both sides all begin to find range; For a side wherein, at first the voltage sample value of calculating book side and resultant current sampled value, voltage sample value and the resultant current sampled value of this side that then will obtain transfer to the circuit offside, and receive voltage sample value and the resultant current sampled value of offside.

Described resultant current sampled value is designated as i _a, i _b, i _c: i _a=i _A1+ i _A2, i _b=i _B1+ i _B2, i _c=i _C1+ i _C2, i _A1, i _B1, i _C1Be respectively this circuit A phase, B phase, C phase current instantaneous sampling value, i _A2, i _B2, i _C2Be respectively adjacent lines A phase, B phase, C phase current instantaneous sampling value.

When circuit generation unbalanced fault,

With

With

Be negative sequence voltage power frequency vector sum negative-sequence current power frequency vector; When circuit generation symmetric fault,

With With

For positive sequence voltage variable quantity vector sum electric current is forward-order current variable quantity vector.

In the step 1), be after fault occurs behind the 20ms and either side protective device when sending trip signal after the protection of the described either side action tripping operation.

The fault localization module comprises: collecting unit: for the protection of transmission line of electricity both sides, the voltage and current to the fault both sides after the protection of the either side action tripping operation gathers; Note wherein side protection is L with the trouble spot distance, and this side is this side, and opposite side is offside, and line length is L _Set

Converting unit: calculate respectively voltage sample value and the resultant current sampled value of both sides, the voltage sample value of every side is got this side bus PT voltage sample value, and every side resultant current sampled value is the current instantaneous value sum of this circuit Yu the adjacent lines of this side;

Resolve the unit: utilize voltage sample value and the resultant current sampled value of both sides, calculating book side voltage vector value The current vector value

The voltage vector value of offside The current vector value

Substitution fault point voltage magnitude calculation equation $\begin{array}{c}\left|{\stackrel{.}{U}}_{\mathrm{mf}}\right|=|{\stackrel{.}{U}}_m-{\stackrel{.}{I}}_m\×\stackrel{.}{Z}\×L|\\ \left|{\stackrel{.}{U}}_{\mathrm{nf}}\right|=|{\stackrel{.}{U}}_n-{\stackrel{.}{I}}_n\×\stackrel{.}{Z}\×(L_{\mathrm{set}}-L)|\end{array},$ In the equation

With Be a side voltage and current vector value,

With

Be opposite side voltage and current vector value. Be the circuit positive sequence impedance; Order | U _Mf| with | U _Mf| equate, resolve the trouble spot apart from the length L of this side protection.

Described collecting unit also comprises communication interface, is used for sending fault both sides wherein voltage sample value and the resultant current sampled value of a side, receives voltage sample value and the resultant current sampled value of opposite side.

Described resultant current sampled value is designated as i _a, i _b, i _c: i _a=i _A1+ i _A2, i _b=i _B1+ i _B2, i _c=i _C1+ i _C2, i _A1, i _B1, i _C1Be respectively this circuit A phase, B phase, C phase current instantaneous sampling value, i _A2, i _B2, i _C2Be respectively adjacent lines A phase, B phase, C phase current instantaneous sampling value.

When circuit generation unbalanced fault,

With With

Be negative sequence voltage power frequency vector sum negative-sequence current power frequency vector; When circuit generation symmetric fault,

With

With

For positive sequence voltage variable quantity vector sum electric current is forward-order current variable quantity vector.

In the collecting unit, be after fault occurs behind the 20ms and either side protective device when sending trip signal after the protection of the described either side action tripping operation.

In intelligent substation; the current sampling data that line protective devices obtain double loop will be very easy to; distance-finding method among the present invention is considered as integral body with double-circuit line; namely synthesize single loop line and carry out fault localization; phase current addition of the same name is as each phase current of single loop line, and voltage is got bus PT measuring voltage.The present invention utilizes the voltage and current of circuit both sides after synthetic to set up respectively the voltage derivation equation of trouble spot, with distance protection installation place, trouble spot distance as known variables.The fault point voltage amplitude of calculating respectively by circuit both sides sampled value should be identical, calculates known variables according to this constraint condition, namely draws the trouble spot apart from the distance of route protection installation place.The present invention has utilized the sampled data of double-circuit line both sides to find range, and double-circuit line is considered as single back line carries out distance calculation the distance accuracy problem in the time of can effectively solving with bar circuit cross line fault.Adopt negative phase-sequence modulus and variable quantity positive sequence modulus in the method, can effectively eliminate the inaccurate impact on distance accuracy of power transmission line zero-sequence loop parameter.

Description of drawings

Fig. 1 is distance-finding method process flow diagram of the present invention;

Fig. 2 is that process of iteration is calculated the trouble spot apart from process flow diagram;

Fig. 3 is the system schematic of embodiment 1;

Fig. 4 is the system schematic of embodiment 2.

Embodiment

The present invention will be further described in detail below in conjunction with accompanying drawing.

Embodiment 1

As shown in Figure 3, the fault localization module that is applied to the intelligent grid transmission line of electricity comprises: collecting unit: for the protection of transmission line of electricity both sides, the voltage and current to the fault both sides after the protection of the either side action tripping operation gathers; Note wherein side protection is L with the trouble spot distance, and this side is this side, and opposite side is offside, and line length is L _SetConverting unit: calculate respectively voltage sample value and the resultant current sampled value of both sides, the voltage sample value of every side is got this side bus PT voltage sample value, and every side resultant current sampled value is the current instantaneous value sum of this circuit Yu the adjacent lines of this side; Resolve the unit: utilize voltage sample value and the resultant current sampled value of both sides, calculating book side voltage vector value The current vector value

The voltage vector value of offside

The current vector value

Substitution fault point voltage magnitude calculation equation $\begin{array}{c}\left|{\stackrel{.}{U}}_{\mathrm{mf}}\right|=|{\stackrel{.}{U}}_m-{\stackrel{.}{I}}_m\×\stackrel{.}{Z}\×L|\\ \left|{\stackrel{.}{U}}_{\mathrm{nf}}\right|=|{\stackrel{.}{U}}_n-{\stackrel{.}{I}}_n\×\stackrel{.}{Z}\×(L_{\mathrm{set}}-L)|\end{array},$ In the equation

With

Be a side voltage and current vector value,

With

Be opposite side voltage and current vector value. Be the circuit positive sequence impedance; Order | U _Mf| with | U _Mf| equate, resolve the trouble spot apart from the length L of this side protection.

The present invention utilizes in the intelligent substation sampled value information to enjoy mutually advantage, and position of failure point calculates to adopt the current sampling data of line double-end double loop to carry out accurately.The trigger condition of fault localization is to carry out after the transmission line of electricity either side is protected the action tripping operation, can guarantee that like this both-end distance measuring calculating still can be carried out in the circuit both sides when circuit one side protective device tripping operation speed.The trip signal of circuit offside comes by the transmission of vertical connection optical-fibre channel.After the fault localization trigger condition satisfied, the fault localization module of circuit both sides protective device was found range.

Embodiment 2

Such as Fig. 4; adopt redundant fashion; adopt two range finder modules; both increase security, and also can increase measurement accuracy by comparison, in the present embodiment; fault localization independently is a module; be integrated in the line protective devices, protect 1 integrated with distance measurement module 1, integrated with distance measurement module 2(protection is that protective device is called for short in the protection 2) in.Range finder module also is provided with communication interface, is used for sending voltage sample value and the resultant current sampled value of this side, receives voltage sample value and the resultant current sampled value of offside.

After line failure started, the either side protective device put into operation when sending trip signal, and each fault is only moved once.For guaranteeing that the range finding result calculates accurately, the power frequency vector calculation in the ranging scheme adopts all-round difference fourier algorithm, after fault occurs behind the 20ms and the either side protective device trigger the flow process of finding range when sending trip signal, such as Fig. 1, comprising:

1, the sampled value of synthetic this circuit of this side and each phase current of adjacent lines, each interval sampling of this side is finished by the process layer collecting device synchronously.Get bus PT voltage as this side of circuit voltage sample value, together be sent to circuit offside protective device with current sampling data after synthetic, simultaneously the voltage and current sample value of the offside that sends over of receiving lines offside.

i _a=i _A1+ i _A2i _b=i _B1+ i _B2i _c=i _C1+ i _C2I in the following formula _A1Be the A phase current instantaneous sampling value of this circuit, i _A2The A phase current instantaneous sampling value of adjacent lines, B, C are mutually by that analogy.

2, utilize the voltage of this side of circuit and voltage, electric current positive sequence power frequency variation and the negative phase-sequence amount that the resultant current sampled value calculates synthetic single loop line.

3, utilize the voltage of receiving lines offside and offside voltage, electric current positive sequence power frequency variation and the negative phase-sequence amount that the resultant current sampled value calculates synthetic single loop line.

4, set up fault point voltage magnitude calculation equation

$\left|{\stackrel{.}{U}}_{\mathrm{mf}}\right|=|{\stackrel{.}{U}}_m-{\stackrel{.}{I}}_m\×\stackrel{.}{Z}\×L|$

$\left|{\stackrel{.}{U}}_{\mathrm{nf}}\right|=|{\stackrel{.}{U}}_n-{\stackrel{.}{I}}_n\×\stackrel{.}{Z}\×(L_{\mathrm{set}}-L)|$

In the formula

With

Be M side (this side) voltage and current vector value,

With

Be N side (offside) voltage and current vector value.

Be circuit positive sequence impedance, L _SetBe line length, L is that the trouble spot is apart from the length of M side (this side).

In the formula | U _Mf| be the fault point voltage mould value of utilizing M side (this side) vector value to calculate, | U _Mf| be the fault point voltage mould value of utilizing N side (offside) vector value to calculate, both should be identical in theory.

When circuit generation unbalanced fault, voltage is negative sequence voltage in the above-mentioned formula, and electric current is negative-sequence current; Corresponding fault point voltage magnitude calculation equation is $\begin{array}{c}\left|{\stackrel{.}{\mathrm{\ΔU}}}_{1f}\right|=|\mathrm{\Δ}{\stackrel{.}{U}}_{1m}-{\mathrm{\Δ}\stackrel{.}{I}}_{1m}\×\stackrel{.}{Z}\×L|\\ \left|{\stackrel{.}{\mathrm{\ΔU}}}_{1f}\right|=|{\mathrm{\Δ}\stackrel{.}{U}}_{1n}-{\mathrm{\Δ}\stackrel{.}{I}}_{1n}\×\stackrel{.}{Z}\×(L_{\mathrm{set}}-L)|\end{array};$

Be positive sequence voltage power frequency variation vector value; Be forward-order current power frequency variation vector value;

Be negative sequence voltage power frequency amount vector value;

Be negative-sequence current power frequency amount vector value;

When circuit generation symmetric fault, voltage is positive sequence variable quantity voltage in the above-mentioned formula, and electric current is positive sequence variable quantity electric current.Corresponding fault point voltage magnitude calculation equation is $\begin{array}{c}\left|{\stackrel{.}{U}}_{2f}\right|=|{\stackrel{.}{U}}_{2m}-{\stackrel{.}{I}}_{2m}\×\stackrel{.}{Z}\×L|\\ \left|{\stackrel{.}{U}}_{2f}\right|=|{\stackrel{.}{U}}_{2n}-{\stackrel{.}{I}}_{2n}\×\stackrel{.}{Z}\×(L_{\mathrm{set}}-L)|\end{array};$

Be positive sequence voltage power frequency variation vector value;

Be forward-order current power frequency variation vector value;

Be negative sequence voltage power frequency amount vector value; Be negative-sequence current power frequency amount vector value;

5, utilize process of iteration to calculate the trouble spot distance L, iterative step is as follows, and such as Fig. 2: (1) supposition L initial value is

Δ X=L; (2) differentiate

Whether satisfy; If satisfy then the trouble spot is L apart from the distance of M side, range finder module is out of service; If do not satisfy, then continue (3); (3) when

The time, get L=L+ Δ X; When

The time, get

L=L-Δ X; (4) utilize (3) the new L that obtains to continue to calculate | U _Mf| and | U _Nf|, carry out (2).

Claims (10)

1. a fault distance-finding method that is used for the intelligent grid transmission line of electricity is characterized in that, step is as follows:

1) for the protection of transmission line of electricity both sides, after the protection action tripping operation of either side, gathers the voltage and current of both sides; Note wherein side protection is L with the trouble spot distance, and this side is this side, and opposite side is offside, and line length is L _Set

2) calculate respectively voltage sample value and the resultant current sampled value of both sides, the voltage sample value of every side is got this side bus PT voltage sample value, and every side resultant current sampled value is the current instantaneous value sum of this circuit Yu the adjacent lines of this side;

3) utilize step 2) voltage sample value and the resultant current sampled value of the both sides that obtain, calculating book side voltage vector value

The current vector value

The voltage vector value of offside

The current vector value Substitution fault point voltage magnitude calculation equation $\begin{array}{c}\left|{\stackrel{.}{U}}_{\mathrm{mf}}\right|=|{\stackrel{.}{U}}_m-{\stackrel{.}{I}}_m\×\stackrel{.}{Z}\×L|\\ \left|{\stackrel{.}{U}}_{\mathrm{nf}}\right|=|{\stackrel{.}{U}}_n-{\stackrel{.}{I}}_n\×\stackrel{.}{Z}\×(L_{\mathrm{set}}-L)|\end{array},$ In the equation

With

Be a side voltage and current vector value,

With Be opposite side voltage and current vector value.

Be the circuit positive sequence impedance; Order | U _Mf| with | U _Mf| equate, resolve the trouble spot apart from the length L of this side protection.

2. fault distance-finding method according to claim 1 is characterized in that, after the protection action tripping operation of either side, both sides all begin to find range; For a side wherein, at first the voltage sample value of calculating book side and resultant current sampled value, voltage sample value and the resultant current sampled value of this side that then will obtain transfer to the circuit offside, and receive voltage sample value and the resultant current sampled value of offside.

3. fault distance-finding method according to claim 1 and 2 is characterized in that, described resultant current sampled value is designated as i _a, i _b, i _c: i _a=i _A1+ i _A2, i _b=i _B1+ i _B2, i _c=i _C1+ i _C2, i _A1, i _B1, i _C1Be respectively this circuit A phase, B phase, C phase current instantaneous sampling value, i _A2, i _B2, i _C2Be respectively adjacent lines A phase, B phase, C phase current instantaneous sampling value.

4. fault distance-finding method according to claim 1 and 2 is characterized in that, when circuit generation unbalanced fault,

With

With

Be negative sequence voltage power frequency vector sum negative-sequence current power frequency vector; When circuit generation symmetric fault,

With

With

For positive sequence voltage variable quantity vector sum electric current is forward-order current variable quantity vector.

5. fault distance-finding method according to claim 1 and 2 is characterized in that, in the step 1), is after fault occurs behind the 20ms and either side protective device when sending trip signal after the protection of the described either side action tripping operation.

6. implement the as claimed in claim 1 fault localization module of fault distance-finding method, it is characterized in that, comprising:

Collecting unit: for the protection of transmission line of electricity both sides, the voltage and current to the fault both sides after the protection of the either side action tripping operation gathers; Note wherein side protection is L with the trouble spot distance, and this side is this side, and opposite side is offside, and line length is L _Set

Converting unit: calculate respectively voltage sample value and the resultant current sampled value of both sides, the voltage sample value of every side is got this side bus PT voltage sample value, and every side resultant current sampled value is the current instantaneous value sum of this circuit Yu the adjacent lines of this side;

Resolve the unit: utilize voltage sample value and the resultant current sampled value of both sides, calculating book side voltage vector value

The current vector value

The voltage vector value of offside

The current vector value Substitution fault point voltage magnitude calculation equation $\begin{array}{c}\left|{\stackrel{.}{U}}_{\mathrm{mf}}\right|=|{\stackrel{.}{U}}_m-{\stackrel{.}{I}}_m\×\stackrel{.}{Z}\×L|\\ \left|{\stackrel{.}{U}}_{\mathrm{nf}}\right|=|{\stackrel{.}{U}}_n-{\stackrel{.}{I}}_n\×\stackrel{.}{Z}\×(L_{\mathrm{set}}-L)|\end{array},$ In the equation

With

Be a side voltage and current vector value,

With

Be opposite side voltage and current vector value.

Be the circuit positive sequence impedance; Order | U _Mf| with | U _Mf| equate, resolve the trouble spot apart from the length L of this side protection.

7. fault localization module according to claim 6, it is characterized in that, described collecting unit also comprises communication interface, is used for sending fault both sides wherein voltage sample value and the resultant current sampled value of a side, receives voltage sample value and the resultant current sampled value of opposite side.

8. according to claim 6 or 7 described fault localization modules, it is characterized in that, described resultant current sampled value is designated as i _a, i _b, i _c: i _a=i _A1+ i _A2, i _b=i _B1+ i _B2, i _c=i _C1+ i _C2, i _A1, i _B1, i _C1Be respectively this circuit A phase, B phase, C phase current instantaneous sampling value, i _A2, i _B2, i _C2Be respectively adjacent lines A phase, B phase, C phase current instantaneous sampling value.

9. according to claim 6 or 7 described fault localization modules, it is characterized in that, when circuit generation unbalanced fault,

With With Be negative sequence voltage power frequency vector sum negative-sequence current power frequency vector; When circuit generation symmetric fault,

With

With

For positive sequence voltage variable quantity vector sum electric current is forward-order current variable quantity vector.

10. according to claim 6 or 7 described fault localization modules, it is characterized in that, in the collecting unit, is after fault occurs behind the 20ms and either side protective device when sending trip signal after the protection of the described either side action tripping operation.

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