CN102157922A - Reactance relay and re-closing method - Google Patents

Abstract

The invention relates to a reactance relay and a re-closing method, the reactance relay is based on the current of a fault point of a mixed circuit of a high-voltage cable and a trolley wire, the reactance relay based on the current of the fault point is the reactance relay based on information of momentary current on two sides of the circuit, the momentary current on two sides of the circuit is utilized, capacitance current of a trolley wire circuit and a cable circuit and the current of a shunt reactor of the trolley wire are compensated, and the precise current of the fault point can be obtained by calculation. As for the mixed circuit of the high-voltage cable and the trolley wire without the shunt reactor, a protector on the trolley wire side is used for judging whether the re-closing is started or not, the protector on the trolley wire side always adopts the synchronous check way for superposition, the action range of the reactance relay is set to the junction of the trolley wire and the cable, if the reactance relay acts, a fault occurs in the trolley wire circuit, the re-closing is started, otherwise, the re-closing is locked. The re-closing is started when the fault occurs in the trolley wire of the mixed circuit, and the re-closing is locked when the fault occurs in the cable.

Description

A kind of reactance relay and reclosing method

Technical field

The present invention relates to a kind of reactance relay and reclosing method, more particularly a kind of method of high voltage cable-overhead line hybrid line reclosing and adopt the device of this method.

Background technology

High voltage cable-overhead line hybrid line can be crossed over big water channel, straits because of it, can not take aboveground space directly to big city and industrial area center feed, beautifies the environment, the reliability height, therefore uses more and more widely.The power cable overhead line hybrid line that moves all adopts conventional overhead transmission line relaying protection at present; because the overhead wire fault generally is a transient fault; need the starting reclosing; and for cable fault; it generally is permanent fault; overlap once more and can produce bigger damage, therefore need the locking reclosing cable.At present for the cable overhead line hybrid line, whether starting reclosing generally decides according to the length relation of circuit and cable, if circuit is longer, generally need to drop into reclosing, if cable is longer, locking reclosing then, this application easily cause the locking of overhead wire fault mistake to overlap, and the cable fault error starting overlaps.For the identification of overhead wire cable fault position, relevant both at home and abroad document is all less, and analyzes comprehensive inadequately.

Summary of the invention

The objective of the invention is: propose a kind of reactance relay and reclosing method, utilization is based on the novel reactance relay of current in the fault point information, the line scan pickup coil side voltage transient fault criterion of combined belt shunt reactor, constitute brand-new starting recloser criterion, be used for distinguishing cut cable and overhead wire segment fault, guarantee the inoperative reclosing of cut cable fault, and built on stilts line segment as far as possible reliably starts reclosing.

Technical scheme of the present invention is: a kind of reactance relay and reclosing method, be provided with reactance relay based on high-tension cable and overhead line hybrid line fault point electric current, described reactance relay based on current in the fault point is based on the reactance relay of circuit both sides transient current information, utilize circuit both sides transient current, and the capacitance current and the overhead wire shunt reactor electric current of compensation overhead wire circuit and cable line, calculate the accurate electric current of fault point.But the line scan pickup coil side voltage transient fault criterion of combined belt shunt reactor constitutes brand-new starting recloser criterion.

High-tension cable and overhead line hybrid line for no shunt reactor; the protection of overhead wire side judges whether to start reclosing; the cable side protection adopts the inspection synchronizing mode to overlap all the time; described reactance relay actuating range is adjusted to overhead wire and cable junction; if described reactance relay action; then the overhead transmission line fault is started reclosing, otherwise the locking reclosing.

High-tension cable and overhead line hybrid line to the band shunt reactor are aided with terminal voltage transient fault criterion, realize transient fault starting reclosing, permanent fault locking reclosing

The criterion of the transient fault of band shunt reactor gets according to the beat frequency voltage characteristic, be also referred to as the beat frequency voltage criterion, if single-phase transient fault takes place, fault phase recovery voltage has the beat frequency characteristic, permanent fault then fault phase recovery voltage keeps constant, is used for distinguishing transient fault and permanent fault;

In the formula, U _Min=ω-ω _z, U _Max=ω+ω _z, ω is a work frequency, ω _ZFor disconnecting the free component frequency that phase energy-storage travelling wave tube charging and discharging circuit forms, m is a threshold value, and representative value is 0.5.

The protection of overhead wire side judges whether to start reclosing; the cable side protection adopts the inspection synchronizing mode to overlap all the time; described reactance relay actuating range is adjusted to overhead wire and cable junction; if described reactance relay action or beat frequency voltage criterion condition satisfy; then the overhead transmission line fault is started reclosing, otherwise the locking reclosing.

The reactance relay characteristic is utilized circuit both sides transient current, the capacitance current and the shunt reactor electric current of overhead wire circuit and cable line have been compensated, obtain the accurate electric current of fault point, thereby realized the high accuracy reactance relay of accurate differentiation cable line fault and overhead wire line fault.The present invention is by exchange line both sides transient current, and in conjunction with condenser current compensation, reactor current compensation, accurate Calculation current in the fault point, constructed the high accuracy reactance relay that can accurately distinguish cable fault and overhead wire fault.

The present invention also is aided with terminal voltage transient fault criterion to the joint line of band shunt reactor, has realized transient fault starting reclosing, the function of permanent fault locking reclosing.

The invention has the beneficial effects as follows: the inventive method can be guaranteed the reliable locking of cut cable fault reclosing; overhead wire fault then maximum possible realizes overlapping; this reclosing comprehensive criterion algorithm is simple, utilizes present existing differential protection just can realize, can not increase extra investment.

Description of drawings

Overhead wire did not stress the open logic that closes a floodgate when Fig. 1 had reactor

Overhead wire stressed the open logic that closes a floodgate when Fig. 2 had reactor

Embodiment

Condition one: reactance relay characteristic of the present invention

1) earth fault:

Operating voltage: ${\stackrel{\·}{U}}_{\mathrm{OP\Φ}}={\stackrel{\·}{U}}_{\mathrm{\Φ}}-({\stackrel{\·}{I}}_{\mathrm{\Φ}}+K\×3{\stackrel{\·}{I}}_0)\×Z_{\mathrm{ZD}}$

Polarizing voltage: ${\stackrel{\·}{U}}_{\mathrm{P\Φ}}=-{\stackrel{\·}{I}}_{\mathrm{f\Φ}}\×Z_{\mathrm{Comp}}$

Then

2) phase-to phase fault:

Operating voltage: ${\stackrel{\·}{U}}_{\mathrm{OP\Φ\Φ}}={\stackrel{\·}{U}}_{\mathrm{\Φ\Φ}}-{\stackrel{\·}{I}}_{\mathrm{\Φ\Φ}}\×Z_{\mathrm{ZD}}$

Polarizing voltage: ${\stackrel{\·}{U}}_{\mathrm{P\Φ\Φ}}=-{\stackrel{\·}{I}}_{\mathrm{f\Φ\Φ}}\×Z_{\mathrm{Comp}}$

Then

In the formula,

Be respectively protection installation place fault phase current, three-phase current, zero-sequence current, fault phase voltage, fault voltage between phases,

Be respectively fault point fault phase current and fault three-phase current, K is a zero sequence current compensation factor, Z _ZDBe the definite value of adjusting, Z _CompBe the unit compensating impedance, its impedance angle is 90 °.Z _KFor measuring impedance.

Calculate fault current And

The time, need to consider condenser current compensation, when shunt reactor, also need to consider the reactor compensation.

3) condenser current compensation

There is following relation between capacitance current and the voltage:

$i_c=C\frac{{\mathrm{du}}_c}{\mathrm{dt}}$

Be compensated for as example mutually with A, ignore the alternate electric capacity of cable, circuit both sides A phase capacitance current instantaneous value i _Amc, i _AncBe respectively:

$\left\{\begin{array}{c}{i}_{\mathrm{amc}}=\frac{C_{\mathrm{pg}\_\mathrm{Line}}}{2}\frac{{\mathrm{du}}_{j1}}{\mathrm{dt}}+\frac{C_{\mathrm{pp}\_\mathrm{Line}}}{2}\frac{{\mathrm{du}}_{\mathrm{ab}1}}{\mathrm{dt}}+\frac{C_{\mathrm{pp}\_\mathrm{Line}}}{2}\frac{{\mathrm{du}}_{\mathrm{ac}1}}{\mathrm{dt}}\\ +\frac{C_{\mathrm{pg}\_\mathrm{Line}}}{2}\frac{{\mathrm{du}}_{j2}}{\mathrm{dt}}+\frac{C_{\mathrm{pp}\_\mathrm{Line}}}{2}\frac{{\mathrm{du}}_{\mathrm{ab}2}}{\mathrm{dt}}+\frac{C_{\mathrm{pp}\_\mathrm{Line}}}{2}\frac{{\mathrm{du}}_{\mathrm{ac}2}}{\mathrm{dt}}\\ i_{\mathrm{anc}}=\frac{C_{\mathrm{pg}\_\mathrm{cable}}}{2}\frac{{\mathrm{du}}_{j3}}{\mathrm{dt}}+\frac{C_{\mathrm{pg}\_\mathrm{cable}}}{2}\frac{{\mathrm{du}}_{j2}}{\mathrm{dt}}\end{array}\right.$

In the formula: C _{Pg_Line}Be line mutual-ground capacitor, C _{Pp_Line}Be the alternate electric capacity of circuit, C _{Pg_cable}Be cable earth capacitance.u _Ab1, u _Ac1Be respectively AB, AC voltage between phases that this side measurement device arrives.u _Ab2, u _Ac2Be respectively AB, AC voltage between phases that electric capacity cable junction calculates, establish u _J2Be electric capacity cable junction instantaneous voltage, u _J1Be the instantaneous voltage that this side measurement device arrives, its computing formula is as follows:

$u_{j2}=u_{j1}\left(t\right)-L_{j1}(\frac{{\mathrm{di}}_{j2}}{\mathrm{dt}}+k_{L0}\frac{{d3i}_{0j2}}{\mathrm{dt}})-R_{j1}(i_{j2}+k_{R0}{3i}_{0j2})$ Formula 4

In the formula: n=a, b, c;

L _J1, L _J0Positive sequence and zero sequence inductance for circuit; R _J1, R _J0Positive sequence and zero sequence resistance for circuit.

4) reactor compensation

With A is example mutually, has following relation between reactor current and the voltage:

$\frac{{\mathrm{di}}_{\mathrm{aL}}}{\mathrm{dt}}=\frac{u_a}{L_p}$

Try to achieve and flow through reactor A phase current and be:

$i_{\mathrm{aL}}\left(t\right)=i_{\mathrm{aL}}(t-\mathrm{\Δt})+\frac{\mathrm{\Δt}}{2\×L_p}[u_a\left(t\right)+u_a(t-\mathrm{\Δt})]$

In the formula, i _ALFor flowing through A be in parallel reactor current, u _aBe A phase voltage, L _pBe shunt reactor phase inductance value.

According to the aforementioned calculation result, be example mutually with A, can flow through the current instantaneous value i of fault point resistance _AfFor:

i _af＝i _afm+i _afn-i _amc-i _anc-i _aL

In the formula, i _Afm, i _AfmBe respectively the A phase current instantaneous value of this side and offside measurement device.

Utilize current instantaneous value can try to achieve the current in the fault point amplitude.B, the compensation method of C phase are mutually identical with A.

Condition two: the transient fault criterion of band shunt reactor

The transient fault criterion is based on band shunt reactor system transient fault tangible beat frequency characteristics design, and transient fault disconnects the phase voltage amplitude and fluctuates up and down, and its pass that disconnects phase voltage maximum and minimum value is:

$\frac{U_{\min }}{U_{\max }}<m$

In the formula, U _Min=ω-ω _z, U _Max=ω+ω _z, ω is a work frequency, ω _ZFor disconnecting the free component frequency that phase energy-storage travelling wave tube charging and discharging circuit forms, m is a threshold, and representative value is 0.5.

Overhead wire cable hybrid line reclosing comprehensive criterion:

Judge whether to start reclosing by the protection of overhead wire side, the cable side protection adopts the inspection synchronizing mode to overlap all the time.Concrete enforcement logic is as follows:

Fig. 1 is the overhead wire open condition that stresses to close a floodgate during for no shunt reactor, the novel reactance relay actuating range of overhead wire side is adjusted to overhead wire and cable junction, if the overhead wire side has novel reactor action of the present invention, then is judged to line fault, starting reclosing, otherwise locking reclosing.

Fig. 2 overhead wire when shunt reactor is arranged stresses the open condition that closes a floodgate, the novel reactance relay actuating range of overhead wire side is adjusted to overhead wire and cable junction, if novel reactor action of overhead wire side or beat frequency voltage criterion condition satisfy, then be judged to line fault or transient fault, starting reclosing, otherwise locking reclosing.And cable side adopts inspection synchronous recloser mode all the time, guarantees only just open reclosing after the success of line side reclosing.

Claims (6)

1. reactance relay and reclosing method, it is characterized in that: reactance relay is provided in a side of the reactance relay based on high-tension cable and overhead line hybrid line fault point electric current, described reactance relay based on current in the fault point is based on the reactance relay of circuit both sides transient current information, utilize circuit both sides transient current, and the capacitance current and the overhead wire shunt reactor electric current of compensation overhead wire circuit and cable line, calculate the accurate electric current of fault point.

2. a kind of reactance relay according to claim 1 and reclosing method; it is characterized in that: for the high-tension cable and the overhead line hybrid line of no shunt reactor; the protection of overhead wire side judges whether to start reclosing; the cable side protection adopts the inspection synchronizing mode to overlap all the time; described reactance relay actuating range is adjusted to overhead wire and cable junction; if described reactance relay action, then the overhead transmission line fault is started reclosing, otherwise the locking reclosing.

3. a kind of reactance relay according to claim 1 and reclosing method, it is characterized in that: high-tension cable and overhead line hybrid line to the band shunt reactor are aided with terminal voltage transient fault criterion, realize transient fault starting reclosing and permanent fault locking reclosing.

4. a kind of reactance relay according to claim 3 and reclosing method, it is characterized in that: the criterion of the transient fault of band shunt reactor gets according to the beat frequency voltage characteristic, be also referred to as the beat frequency voltage criterion, if single-phase transient fault takes place, fault phase recovery voltage has the beat frequency characteristic, permanent fault then fault phase recovery voltage keeps constant, is used for distinguishing transient fault and permanent fault;

$\frac{U_{\min }}{U_{\max }}<m$

In the formula, U _Min=ω-ω _z, U _Max=ω+ω _z, ω is a work frequency, ω _ZFor disconnecting the free component frequency that phase energy-storage travelling wave tube charging and discharging circuit forms, m is a threshold, and representative value is 0.5.

5. according to claim 1 or 2 or 3 described a kind of reactance relay and reclosing methods; it is characterized in that: the protection of overhead wire side judges whether to start reclosing; the cable side protection adopts the inspection synchronizing mode to overlap all the time; described reactance relay actuating range is adjusted to overhead wire and cable junction; if described reactance relay action or beat frequency voltage criterion condition satisfy; then the overhead transmission line fault is started reclosing, otherwise the locking reclosing.

6. according to claim 1 or 2 or 3 described a kind of reactance relay and reclosing methods, it is characterized in that

The characteristic of described reactance relay is as follows:

1) earth fault:

Operating voltage: ${\stackrel{\&CenterDot;}{U}}_{\mathrm{OP\&Phi;}}={\stackrel{\&CenterDot;}{U}}_{\mathrm{\&Phi;}}-({\stackrel{\&CenterDot;}{I}}_{\mathrm{\&Phi;}}+K\&times;3{\stackrel{\&CenterDot;}{I}}_0)\&times;Z_{\mathrm{ZD}}$

Polarizing voltage: ${\stackrel{\&CenterDot;}{U}}_{\mathrm{P\&Phi;}}=-{\stackrel{\&CenterDot;}{I}}_{\mathrm{f\&Phi;}}\&times;Z_{\mathrm{Comp}}$

Then

Formula 1

2) phase-to phase fault:

Operating voltage: ${\stackrel{\&CenterDot;}{U}}_{\mathrm{OP\&Phi;\&Phi;}}={\stackrel{\&CenterDot;}{U}}_{\mathrm{\&Phi;\&Phi;}}-{\stackrel{\&CenterDot;}{I}}_{\mathrm{\&Phi;\&Phi;}}\&times;Z_{\mathrm{ZD}}$

Polarizing voltage: ${\stackrel{\&CenterDot;}{U}}_{\mathrm{P\&Phi;\&Phi;}}=-{\stackrel{\&CenterDot;}{I}}_{\mathrm{f\&Phi;\&Phi;}}\&times;Z_{\mathrm{Comp}}$

Then Formula 2

In the formula,

Be respectively protection installation place fault phase current, three-phase current, zero-sequence current, fault phase voltage, fault voltage between phases, Be the fault point fault current, K is a zero sequence current compensation factor, Z _ZDBe the definite value of adjusting, Z _CompBe the unit compensating impedance, its impedance angle is 90 °, Z _KFor measuring impedance.

Calculate fault current

And

The time, need to consider condenser current compensation, when shunt reactor, need to consider the reactor current compensation;

3) condenser current compensation

There is following relation between capacitance current and the voltage:

$i_c=C\frac{{\mathrm{du}}_c}{\mathrm{dt}}$

Be compensated for as example mutually with A, ignore the alternate electric capacity of cable, circuit both sides A phase capacitance current instantaneous value i _Amc, i _AncBe respectively:

$\left\{\begin{array}{c}{i}_{\mathrm{amc}}=\frac{C_{\mathrm{pg}\_\mathrm{Line}}}{2}\frac{{\mathrm{du}}_{j1}}{\mathrm{dt}}+\frac{C_{\mathrm{pp}\_\mathrm{Line}}}{2}\frac{{\mathrm{du}}_{\mathrm{ab}1}}{\mathrm{dt}}+\frac{C_{\mathrm{pp}\_\mathrm{Line}}}{2}\frac{{\mathrm{du}}_{\mathrm{ac}1}}{\mathrm{dt}}\\ +\frac{C_{\mathrm{pg}\_\mathrm{Line}}}{2}\frac{{\mathrm{du}}_{j2}}{\mathrm{dt}}+\frac{C_{\mathrm{pp}\_\mathrm{Line}}}{2}\frac{{\mathrm{du}}_{\mathrm{ab}2}}{\mathrm{dt}}+\frac{C_{\mathrm{pp}\_\mathrm{Line}}}{2}\frac{{\mathrm{du}}_{\mathrm{ac}2}}{\mathrm{dt}}\\ i_{\mathrm{anc}}=\frac{C_{\mathrm{pg}\_\mathrm{cable}}}{2}\frac{{\mathrm{du}}_{j3}}{\mathrm{dt}}+\frac{C_{\mathrm{pg}\_\mathrm{cable}}}{2}\frac{{\mathrm{du}}_{j2}}{\mathrm{dt}}\end{array}\right.$ Formula 3

In the formula: C _{Pg_Line}Be line mutual-ground capacitor, C _{Pp_Line}Be the alternate electric capacity of circuit, C _{Pg_cable}Be cable earth capacitance; u _Ab1, u _Ac1Be respectively AB, AC voltage between phases that this side measurement device arrives.u _Ab2, u _Ac2Be respectively AB, AC voltage between phases that electric capacity cable junction calculates, establish u _J2Be electric capacity cable junction instantaneous voltage, u _J1Be the instantaneous voltage that this side measurement device arrives, its computing formula is as follows:

$u_{j2}=u_{j1}\left(t\right)-L_{j1}(\frac{{\mathrm{di}}_{j2}}{\mathrm{dt}}+k_{L0}\frac{{d3i}_{0j2}}{\mathrm{dt}})-R_{j1}(i_{j2}+k_{R0}{3i}_{0j2})$ Formula 4

In the formula: n=a, b, c;

L _J1, L _J0Positive sequence and zero sequence inductance for circuit; R _J1, R _J0Positive sequence and zero sequence resistance for circuit;

4) reactor compensation

With A is example mutually, has following relation between reactor current and the voltage:

$\frac{{\mathrm{di}}_L^a}{\mathrm{dt}}=\frac{u_a}{L_p}$

Try to achieve and flow through reactor A phase current and be:

$i_L^a\left(t\right)=i_L^a(t-\mathrm{\&Delta;t})+\frac{\mathrm{\&Delta;t}}{2\&times;L_p}[u_a\left(t\right)+u_a(t-\mathrm{\&Delta;t})].$