CN101614779B - Method for determining turn-to-turn short circuit, two-phase short circuit and single-phase short circuit of parallel reactors - Google Patents

Abstract

The invention discloses a method for determining the turn-to-turn short circuit, two-phase short circuit and single-phase short circuit of parallel reactors, which comprises the following steps: (1) calculating a fault component delta*2 of a negative sequence voltage according to measurement; (2) calculating a fault component delta*2 of a negative sequence current according to measurement; (3) substituting the delta*2 and the delta*2 into a formula (A) expressed as the absolute value of (delta*2-jdelta*2XL2) is more than or equal to the absolute value of (delta*2+jdelta*2XS2), wherein the formula (A) is an operational equation of a voltage absolute value comparison type negative sequence directional relay, and in the formula, XL2 represents the negative sequence reactance of the reactors and XS2 represents system negative sequence reactance; and (4) if the formula A is valid, determining that parallel reactors having ungrounded neutral points have an internal turn-to-turn short circuit or two-phase short circuit fault, and if the neutral points of the parallel reactors are directly grounded or grounded by small reactors, determining that the parallel reactors directly grounded or grounded by small reactors have an internal turn-to-turn short circuit or two-phase circuit or single-phase circuit fault. The method is mainly used for relay protection devices of high-voltage parallel reactors.

Description

Differentiate the method for shunt reactor turn-to-turn short circuit, line to line fault and single-phase short circuit

Technical field

The present invention relates to a kind of method of differentiating shunt reactor turn-to-turn short circuit, line to line fault and single-phase short circuit, belong to power system main equipment relay protection field.

Background technology

Directional relay in the current domestic and international relay protection field (or claiming directional element, direction criterion) has following several:

The power direction relay of (1) 90 ° of wiring

Be widely used in the relay protection of transmission line of electricity, generator, transformer;

Its elemental motion equation is:

α is the relay interior angle, Be the sensitiveest angle

α (or

) value can adjust, as α=30 ° or 45 °,

Or 45 °;

Because that the reflection of this kind method is the power I of reactor head end _AU _BC, I _BU _CA, I _CU _AB, when reactor interturn short circuit, these performance numbers change minimum, can't detect, so this power direction relay can not be used to differentiate turn-to-turn short circuit.

(2) zero sequence power direction relay

Be widely used in the relay protection of transmission line of electricity, transformer:

Its elemental motion equation is:

Residual voltage, zero-sequence current for the relay measurement;

α (or ) value can adjust, as the zero sequence power direction relay setting interior angle of transformer, transmission line of electricity=110 °, i.e. the sensitiveest angle

(3) the negative sequence power directional relay of fault component

Be applied to the relay protection of generator turn-to-turn short circuit, send out the technical specification of change group protection referring to the WFB-800 that is permitted relay company;

Its elemental motion equation is:

ε _pIt is a wicket bank performance number

In the formula,

The negative phase-sequence fault component voltage of the generator machine end of measuring for relay;

For

Conjugate vector, and

The negative phase-sequence fault component electric current of the generator machine end of measuring for relay;

Be the sensitiveest angle of relay,

Adjust by generator negative sequence impedance angle, generally adjust

Because that the reflection of this kind method of discrimination is negative sequence power (the Δ U of reactor head end ₂Δ I ₂), when the number of turn of reactor interturn short circuit after a little while, Δ U ₂And Δ I ₂All little, the negative sequence power of the two product is little, again the threshold value ε of relay setting _pBe a fixing constant, cause tripping of negative sequence power directional relay or sensitivity low.

(4) absolute value of voltage comparison expression zero sequence direction relay

This relay can determine the turn-to-turn short circuit and the single-phase grounding fault of shunt reactor, sees Chinese patent application prospectus CN101071151A, and open day is on November 14th, 2007, and its elemental motion equation is:

$|{\stackrel{\·}{U}}_0-j{\stackrel{\·}{I}}_0{X}_{L0}|\≥{|\stackrel{\·}{U}}_0+j{\stackrel{\·}{I}}_0{X}_{S0}|$

In the formula,

---the residual voltage of the shunt reactor head end that relay is measured;

---the zero-sequence current of the shunt reactor head end that relay is measured;

X _L0---the zero-sequence reactance of shunt reactor;

X _S0---the zero-sequence reactance of system.

But this kind method of discrimination is lower for the shunt reactor sensitivity of isolated neutral, for example under the situation of the turn-to-turn short circuit number of turn of shunt reactor and ratio β=3% of every total number of turns mutually: and (1), for the shunt reactor of isolated neutral, because So can not differentiate reactor interturn short circuit fault; (2) when neutral point during through too small reactor ground connection, because

So remolding sensitivity is relatively poor, (I wherein _nBe the rated current of reactor, I ₀Zero-sequence current for reactor)

Summary of the invention

At the deficiencies in the prior art, the technical problem to be solved in the present invention provides a kind ofly can differentiate shunt reactor turn-to-turn short circuit, line to line fault and single-phase short circuit and highly sensitive method simultaneously.

For solving the problems of the technologies described above, the technical solution used in the present invention is: a kind of method of differentiating shunt reactor turn-to-turn short circuit, line to line fault and single-phase short circuit comprises the steps:

(1) fault component of measurement and calculating reactor head end three-phase voltage

And then calculate the fault component of negative sequence voltage

(2) fault component of measurement and calculating reactor head end three-phase current

And then calculate the fault component of negative-sequence current

(3) will

Substitution formula (A);

Formula (A) is the operation equation of absolute value of voltage comparison expression negative sequence direction relay:

$|{\mathrm{\&Delta;}\stackrel{\&CenterDot;}{U}}_2-\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{X}_{L20}|\&GreaterEqual;|\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_2+j{\mathrm{\&Delta;}\stackrel{\&CenterDot;}{I}}_2{\mathrm{<figure-callout\; id="2"\; label="X\; S"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">X</figure-callout>}}_S|---\left(A\right)$

In the formula, X _L2---the negative sequence neactance of reactor;

X _S2---the negative sequence neactance of system;

(4) if formula (A) is set up, there are turn-to-turn short circuit or two-phase short-circuit fault in the shunt reactor inside that then determines isolated neutral; If the neutral-point solid ground of shunt reactor or through little reactor ground connection, then determining reactor inside has turn-to-turn short circuit or line to line fault or single-phase grounding fault.

Another kind of technical scheme of the present invention has adopted a kind of method of differentiating shunt reactor turn-to-turn short circuit, line to line fault and single-phase short circuit, comprises the steps:

(1) three-phase voltage of measurement and calculating reactor head end

And then calculate negative sequence voltage

(2) measure and calculate reactor head end three-phase current

And then calculate negative-sequence current

(3) will

Substitution formula (B),

Formula (B) is the operation equation of absolute value of voltage comparison expression negative sequence direction relay;

$|{\stackrel{\&CenterDot;}{U}}_2-j{\stackrel{\&CenterDot;}{I}}_2{\mathrm{<figure-callout\; id="2"\; label="X\; L"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">X</figure-callout>}}_L|\&GreaterEqual;{|\stackrel{\&CenterDot;}{U}}_2+j{\stackrel{\&CenterDot;}{I}}_2{\mathrm{<figure-callout\; id="2"\; label="X\; S"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">X</figure-callout>}}_S|---\left(B\right)$

In the formula, X _L2---the negative sequence neactance of reactor;

X _S2---the negative sequence neactance of system;

(4) if formula (B) is set up, for the earth-free shunt reactor of neutral point, then determining reactor inside has turn-to-turn short circuit or two-phase short-circuit fault; For neutral-point solid ground or through the shunt reactor of little reactor ground connection, then determining reactor inside has turn-to-turn short circuit or line to line fault or single-phase grounding fault.

The present invention's " absolute value of voltage comparison expression negative sequence direction relay " is mainly used in the protective relaying device of high-voltage shunt reactor.If the isolated neutral of shunt reactor, the present invention can determine the turn-to-turn short circuit and the inner two-phase short-circuit fault of reactor; If the neutral-point solid ground of shunt reactor or through little reactor ground connection, the present invention can determine the turn-to-turn short circuit of reactor, inner line to line fault and inner single-phase grounding fault.

The present invention's " absolute value of voltage comparison expression negative sequence direction relay " in the number of turn of reactor interturn short circuit after a little while, though Δ U ₂And Δ I ₂All little, but because the negative sequence neactance X of reactor _L2Very big, cause the actuating quantity of relay

Still have suitable value, and its braking amount is zero, so the actuating of relay of the present invention is highly sensitive.The operation equation method of negative sequence direction relay of the present invention again is simpler than the method for negative sequence power directional relay.

" the absolute value of voltage comparison expression zero sequence direction relay " described in the background technology can determine the turn-to-turn short circuit of shunt reactor, but its overall performance is not as negative sequence direction relay of the present invention.According to analytical calculation, under the situation of the turn-to-turn short circuit number of turn of shunt reactor and ratio β=3% of every total number of turns mutually to real system: if the neutral-point solid ground of reactor, the head end of reactor

(I _nRated current for reactor); If the neutral point of reactor is through little reactor ground connection,

If the isolated neutral of reactor,

As seen, relay of the present invention was compared with " absolute value of voltage comparison expression zero sequence direction relay " (being called for short the latter):

The shunt reactor turn-to-turn short circuit of neutral-point solid ground, action sensitivity of the present invention is identical with the latter;

Neutral point is through the shunt reactor turn-to-turn short circuit of little reactor ground connection, and action sensitivity of the present invention is higher than the latter;

The shunt reactor turn-to-turn short circuit of isolated neutral, the present invention can determine and the latter can not.

Description of drawings

Fig. 1 is shunt reactor turn-to-turn short circuit negative sequence network figure;

Fig. 2 a is the inner line to line fault negative sequence network of shunt reactor figure;

Fig. 2 b is the outside line to line fault negative sequence network of shunt reactor figure;

Fig. 3 a is the inner single-line to ground fault negative sequence network of shunt reactor figure;

Fig. 3 b is the outside single-line to ground fault negative sequence network of shunt reactor figure;

Fig. 4 is the structural representation of embodiments of the present invention.

Embodiment

Absolute value comparison expression negative sequence direction relay " the method operation equation have two kinds: first kind is the negative sequence voltage fault component that the measuring voltage of relay adopts the reactor head end Measure the negative-sequence current fault component that electric current adopts the reactor head end

Second kind is the negative sequence voltage of the measuring voltage employing reactor head end of relay

Measure the negative-sequence current that electric current adopts the reactor head end

The user can choose any one kind of them with control word, and first kind acting characteristic precision is higher than second kind, but first kind method is complicated.

Below analyze the first method operation equation:

Operation equation:

$|{\mathrm{\&Delta;}\stackrel{\&CenterDot;}{U}}_2-\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{X}_{L20}|\&GreaterEqual;|\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_2+j{\mathrm{\&Delta;}\stackrel{\&CenterDot;}{I}}_2{\mathrm{<figure-callout\; id="2"\; label="X\; S"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">X</figure-callout>}}_S|---\left(1\right)$

In the formula,

Be actuating quantity;

Be the braking amount;

X _L2---be the negative sequence neactance of shunt reactor;

X _S2---be the negative sequence neactance of system.

1, shunt reactor turn-to-turn short circuit

See shunt reactor turn-to-turn short circuit negative sequence network figure shown in Figure 1.

$\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_2=-\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_2\&times;\mathrm{<figure-callout\; id="2"\; label="j\; X\; S"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">j</figure-callout>}{X}_S{2}_{}=-\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{X}_{S2}---\left(2\right)$

Lag behind

With formula (2) substitution formula (1),

$|-\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{X}_{S2}-\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{\mathrm{<figure-callout\; id="2"\; label="X\; L"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">X</figure-callout>}}_L|>|-\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{\mathrm{<figure-callout\; id="2"\; label="X\; S"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">X</figure-callout>}}_S+\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{\mathrm{<figure-callout\; id="2"\; label="X\; S"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">X</figure-callout>}}_S|$

|ΔI ₂(X _S2+X _L2)＞0

Actuating quantity is very big, and the braking amount is zero, and the present invention's " negative sequence direction relay " action is the sensitiveest.

2, the inner line to line fault of shunt reactor

See the inner line to line fault negative sequence network of the shunt reactor shown in Fig. 2 a figure

$\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_2=-\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_2\&times;\mathrm{<figure-callout\; id="2"\; label="j\; X\; S"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">j</figure-callout>}{X}_S{2}_{}=-\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{X}_{S2}---\left(3\right)$

Lag behind

With formula (3) substitution formula (1), the gained conclusion is identical with inner turn-to-turn short circuit, and actuating quantity is very big, and the braking amount is zero, and the present invention's " negative sequence direction relay " action is the sensitiveest.

3, the outside line to line fault of shunt reactor

See the outside line to line fault negative sequence network of the shunt reactor shown in Fig. 2 b figure.

$\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_2=\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_2\&times;\mathrm{<figure-callout\; id="2"\; label="j\; X\; S"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">j</figure-callout>}{X}_S{2}_{}=\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{X}_{S2}---\left(4\right)$

Be ahead of

With formula (4) substitution formula (1),

$|\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{X}_{L2}-\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{\mathrm{<figure-callout\; id="2"\; label="X\; L"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">X</figure-callout>}}_L|<|\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{\mathrm{<figure-callout\; id="2"\; label="X\; L"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">X</figure-callout>}}_L+\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{\mathrm{<figure-callout\; id="2"\; label="X\; S"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">X</figure-callout>}}_S|$

0＜ΔI ₂(X _L2+X _S2)

Actuating quantity is zero, and the braking amount is very big, and the present invention's " negative sequence direction relay " reliably is failure to actuate.

4, the shunt reactor neutral-point solid ground in the earth neutral system or under little reactor ground connection situation the inner single-line to ground fault of reactor

See the neutral-point solid ground shown in Fig. 3 a or through the inner single-phase earthing negative sequence network of the shunt reactor of little reactor ground connection figure

$\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_2=-\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_2\&times;\mathrm{<figure-callout\; id="2"\; label="j\; X\; S"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">j</figure-callout>}{X}_S{2}_{}=-\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{X}_{S2}---\left(5\right)$

Lag behind

With formula (5) substitution formula (1), the gained conclusion is identical with the inner line to line fault of reactor, and actuating quantity is very big, and the braking amount is zero, and the present invention's " negative sequence direction relay " action is the sensitiveest.

5, the shunt reactor neutral-point solid ground in the earth neutral system or under little reactor ground connection situation the outside single-line to ground fault of reactor

See the neutral-point solid ground shown in Fig. 3 b or through the outside single-phase earthing negative sequence network of the shunt reactor of little reactor ground connection figure

$\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{U}}_2=\mathrm{\&Delta;}{\stackrel{\&CenterDot;}{I}}_2\&times;\mathrm{<figure-callout\; id="2"\; label="j\; X\; L"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">j</figure-callout>}{X}_L{2}_{}=\mathrm{j\&Delta;}{\stackrel{\&CenterDot;}{I}}_2{X}_{L2}---\left(6\right)$

Be ahead of

With formula (6) substitution formula (1), the gained conclusion is identical with the outside line to line fault of reactor, and actuating quantity is zero, and the braking amount is very big, and the present invention's " negative sequence direction relay " is failure to actuate reliably.

The present invention " absolute value of voltage comparison expression negative sequence direction relay " the second method operation equation be

$|{\stackrel{\&CenterDot;}{U}}_2-j{\stackrel{\&CenterDot;}{I}}_2{\mathrm{<figure-callout\; id="2"\; label="X\; L"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">X</figure-callout>}}_L|\&GreaterEqual;|{\stackrel{\&CenterDot;}{U}}_2+j{\stackrel{\&CenterDot;}{I}}_2{\mathrm{<figure-callout\; id="2"\; label="X\; S"\; filenames="H200910303837220090629E000011.png,H200910303837220090629E000012.png"\; state="\{\{state\}\}">X</figure-callout>}}_S|---\left(7\right)$

In the formula, The negative sequence voltage of Zhao shunt reactor head end;

The negative-sequence current of Zhao shunt reactor head end.

Correspondingly the action behavior with the first method operation equation is identical in the action behavior analysis of second method operation equation when shunt reactor turn-to-turn short circuit, internal-external line to line fault, internal-external single-phase earthing, repeats no more.

Claims (2)

1. a method of differentiating shunt reactor turn-to-turn short circuit, line to line fault and single-line to ground fault is characterized in that, may further comprise the steps:

(1) fault component of measurement and calculating shunt reactor head end three-phase voltage

,

,

, and then calculate the fault component of negative sequence voltage

(2) fault component of measurement and calculating shunt reactor head end three-phase current

,

,

, and then calculate the fault component of negative-sequence current

(3) will

,

Substitution formula (A)

Formula (A) is the operation equation of absolute value of voltage comparison expression negative sequence direction relay:

(A)

In the formula, ---the negative sequence neactance of shunt reactor;

Negative sequence neactance for system;

(4) if formula (A) is set up, there are turn-to-turn short circuit or two-phase short-circuit fault in the shunt reactor inside that then determines isolated neutral; If the neutral-point solid ground of shunt reactor or through little reactor ground connection, then determining shunt reactor inside has turn-to-turn short circuit or line to line fault or single-phase grounding fault.

2. a method of differentiating shunt reactor turn-to-turn short circuit, line to line fault and single-line to ground fault is characterized in that, may further comprise the steps:

(1) three-phase voltage of measurement and calculating shunt reactor head end

,

,

, and then calculate negative sequence voltage

(2) measure and calculate shunt reactor head end three-phase current

,

,

, and then calculate negative-sequence current

(3) will ,

Substitution formula (B)

Formula (B) is the operation equation of absolute value of voltage comparison expression negative sequence direction relay:

(B)

In the formula, ---the negative sequence neactance of shunt reactor;

---the negative sequence neactance of system;

(4) if formula (B) is set up, for the earth-free shunt reactor of neutral point, then determining shunt reactor inside has turn-to-turn short circuit or two-phase short-circuit fault; For neutral-point solid ground or through the shunt reactor of little reactor ground connection, then determining shunt reactor inside has turn-to-turn short circuit or line to line fault or single-phase grounding fault.

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