CN104035001B - A kind of detection method of voltage transformer disconnection - Google Patents

Abstract

A kind of detection method of voltage transformer disconnection; in hydroenergy storage station, generator protection voltage transformer (VT) is two; comprise the voltage transformer (VT) one in generating direction and the voltage transformer (VT) two in direction of drawing water; the detection method of voltage transformer disconnection comprises the steps: the voltage signal gathered from voltage transformer (VT) one and voltage transformer (VT) two, and obtains line voltage U by calculating ¹ _aB, U ¹ _bC, U ¹ _cAand U ² _aB, U ² _bC, U ² _cA; Calculate the line voltage amplitude value difference △ U of two voltage transformer (VT) _aB, △ U _bCwith △ U _cA, judge whether voltage transformer (VT) breaks.The present invention is applicable to the various mode of connection of pump storage plant generator machine machine end, and simplify the wire break detection method of various mode of connection voltage transformer (VT), widely applicable, reliability is high, is convenient to realize on general Microcomputer Protection.

Description

A kind of detection method of voltage transformer disconnection

Technical field

The present invention relates to a kind of Generator end voltage transformer disconnection (though generating direction or draw water direction can) detection method, specifically a kind of voltage balance method detects the method for pumped-storage power generation machine protective voltage transformer, broken string.

Background technology

At present; the task of voltage transformer (VT) is permission voltage primary side voltage being converted into exactly relay protection and secondary instrument; protective relaying device and instrument can be worked under low voltage condition, the ruuning situation of electric system mesohigh equipment can be reflected again exactly.

In hydroenergy storage station; because unit operation is in generating and two different operating modes of drawing water; generator protection voltage transformer (VT) is also set to generating direction accordingly and draws water two, direction independently voltage transformer (VT), and voltage transformer disconnection is one of common fault.When there is voltage transformer disconnection fault, locking immediately should protect accordingly and aut.eq. function, send warning information prompting operations staff process simultaneously.If take measures not in time when voltage transformer (VT) breaks down, the correctness of relay protection and aut.eq. will be had a strong impact on.

Summary of the invention

The object of the invention is the problem being difficult to detection for voltage transformer disconnection; a kind of voltage transformer disconnection detection method being applicable to the various mode of connection of pump storage plant generator machine protection is proposed; widely applicable, reliability is high, is convenient to general Microcomputer Protection realizes.

Technical scheme of the present invention is:

A kind of detection method of voltage transformer disconnection; in hydroenergy storage station, generator protection voltage transformer (VT) is two; comprise the voltage transformer (VT) one in generating direction and the voltage transformer (VT) two in direction of drawing water, the detection method of voltage transformer disconnection comprises the steps:

(1), from voltage transformer (VT) one PT1 gather voltage signal, and obtain line voltage U by calculating ¹ _aB, U ¹ _bC, U ¹ _cA;

(2), from voltage transformer (VT) two PT2 gather voltage signal, and obtain line voltage U by calculating ² _aB, U ² _bC, U ² _cA;

(3), compare the relation of two each line voltage magnitudes of voltage transformer (VT), namely calculate the line voltage amplitude value difference △ U of two voltage transformer (VT) _aB, △ U _bCwith △ U _cA, judge whether voltage transformer (VT) breaks.

In the present invention, compare the relation of two each line voltage magnitudes of voltage transformer (VT), when line voltage corresponding to two voltage transformer (VT) difference in magnitude any one be greater than setting valve Uzd time, then judge voltage transformer (VT) occur broken string.

In the present invention, described setting valve Uzd is fixed according to detected voltage transformer secondary side load symmetric case, 0.15 ~ 0.3 times that gets voltage transformer (VT) rated voltage.

In the present invention, setting valve Uzd gets 0.15 times of voltage transformer (VT) rated voltage.

In the present invention, gathering voltage signal from voltage transformer (VT) one, two is phase voltage, after filtering circuit, convert digital quantity signal to by analog signals, obtains line voltage U as calculated ¹ _aB, U ¹ _bC, U ¹ _cAand U ² _aB, U ² _bC, U ² _cA.

In the present invention, in step (3), △ U _aB, △ U _bCwith △ U _cAcalculation procedure be specially:

To line voltage U ¹ _aBcalculate vector R _1AB+ JX _1AB, calculate U according to vector meter ¹ _aBamplitude:

$\left|{U^1}_{\mathrm{AB}}\right|=\sqrt{R_{1\mathrm{AB}}^2+X_{1\mathrm{AB}}^2}$

To line voltage U ² _aBcalculate vector formulas R _2AB+ JX _2AB, calculate U according to vector meter ² _aBamplitude:

$\left|{U^2}_{\mathrm{AB}}\right|=\sqrt{R_{2\mathrm{AB}}^2+X_{2\mathrm{AB}}^2}$

Obtain, △ U _aB=︱ ︱ U ¹ _aB︱-︱ U ² _aB︱ ︱

In like manner, △ U _bC=︱ ︱ U ¹ _bC︱-︱ U ² _bC︱ ︱

△U _CA＝︱︱U ¹ _CA︱-︱U ² _CA︱︱。

Beneficial effect of the present invention:

The present invention is applicable to the various mode of connection of pump storage plant generator machine machine end, and simplify the wire break detection method of various mode of connection voltage transformer (VT), widely applicable, reliability is high, is convenient to realize on general Microcomputer Protection.

Accompanying drawing explanation

Fig. 1 is structural representation of the present invention;

Fig. 2 is voltage transformer (VT) one BC two-phase broken string, voltage vector diagram when voltage transformer (VT) two does not break;

Fig. 3 is voltage transformer (VT) one A single-phase wire break, voltage vector diagram when voltage transformer (VT) two does not break.

Embodiment

Below in conjunction with drawings and Examples, the present invention is further illustrated.

As shown in Figure 1, for generator terminal voltage mutual inductor (hereinafter referred to as the PT) mode of connection that hydroenergy storage station is conventional, the phase voltage that Generator end PT measures, converts digital quantity signal to by analog signals after filtering circuit, obtains PT1 line voltage U as calculated ¹ _aB, U ¹ _bC, U ¹ _cA, and PT2 line voltage U ² _aB, U ² _bC, U ² _cA.Above-mentioned voltage enters balance of voltage comparison module, respectively to U ¹ _aBand U ² _aB, U ¹ _bCand U ² _bC, U ¹ _cAand U ² _cAcarry out calculating, detecting.

With U ¹ _aBand U ² _aBfor example:

To PT1 line voltage U ¹ _aBcalculate vector R _1AB+ JX _1AB, calculate U according to vector meter ¹ _aBamplitude:

$\left|{U^1}_{\mathrm{AB}}\right|=\sqrt{R_{1\mathrm{AB}}^2+X_{1\mathrm{AB}}^2}$

To PT2 line voltage U ² _aBcalculate vector formulas R _2AB+ JX _2AB, calculate U according to vector meter ² _aBamplitude:

$\left|{U^2}_{\mathrm{AB}}\right|=\sqrt{R_{2\mathrm{AB}}^2+X_{2\mathrm{AB}}^2}$

Obtain, △ U _aB=︱ ︱ U ¹ _aB︱-︱ U ² _aB︱ ︱

In like manner, △ U _bC=︱ ︱ U ¹ _bC︱-︱ U ² _bC︱ ︱

△U _CA＝︱︱U ¹ _CA︱-︱U ² _CA︱︱

As △ U _aB, △ U _bC, △ U _cAwhen any one is greater than Uzd (setting valve), then thinks and occur that PT is with no pressure, outlet PT breaks.Uzd=nUe, is generally getting n=0.15 ~ 0.3.When there is not the situation that PT breaks, △ U _aB, △ U _bC, △ U _cAbe equal to 0.

Here is in the various broken string situation of PT, the amplitude Characteristics situation of line voltage.

A, three-phase break: when broken string all occurs PT1 three-phase, U in theory ¹ _aB, U ¹ _bC, U ¹ _cAamplitude be zero, △ U _aB, △ U _bC, △ U _cAall be greater than Uzd.

B, two-phase break: when broken string occurs PT1B, C phase, U ¹ _band U ¹ _cbe equal to 0.As calculated, show that the line voltage of PT1 is: ︱ U ¹ _aB︱=︱ U ¹ _a︱, ︱ U ¹ _bC︱=0, ︱ U ¹ _cA︱=︱ U ¹ _a︱.Analysis obtains, and the maximum line voltage of PT1 is identical with former phase voltage amplitude, and the minimum amplitude of line voltage is 0.Vector plot as shown in Figure 2.

$\mathrm{\Δ}{U}_{\mathrm{AB}}=\left|\right|{U^1}_A|-|{U^2}_{\mathrm{AB}}\left|\right|=(\sqrt{3}-1)\left|{U^1}_A\right|>\mathrm{Uzd}$

$\mathrm{\Δ}{U}_{\mathrm{BC}}=\left|{U^2}_{\mathrm{BC}}\right|=\sqrt{3}\left|{U^1}_A\right|>\mathrm{Uzd}$

$\mathrm{\Δ}{U}_{\mathrm{CA}}=\left|\right|{U^1}_A|-|{U^2}_{\mathrm{CA}}\left|\right|=(\sqrt{3}-1)\left|{U^1}_A\right|>\mathrm{Uzd}$

C, single-phase wire break: when broken string occurs PT1A phase, U ¹ _aequal 0.As calculated, show that the line voltage of PT1 is: ︱ U ¹ _aB︱=︱ U ¹ _b︱, ︱ U ¹ _bC︱=︱ U ¹ _bC︱, ︱ U ¹ _cA︱=︱ U ¹ _c︱.Analysis obtains, and the maximum line voltage of PT1 is identical with former line voltage magnitude, and the minimum amplitude of line voltage is identical with former phase voltage amplitude.Vector plot as shown in Figure 3.

$\mathrm{\Δ}{U}_{\mathrm{AB}}=\left|\right|{U^1}_B|-|{U^2}_{\mathrm{BA}}\left|\right|=(\sqrt{3}-1)\left|{U^1}_B\right|>\mathrm{Uzd}$

△U _BC＝︱︱U ¹ _BC︱-︱U ² _BC︱︱＝0

$\mathrm{\Δ}{U}_{\mathrm{CA}}=\left|\right|{U^1}_C|-|{U^2}_{\mathrm{CA}}\left|\right|=(\sqrt{3}-1)\left|{U^1}_B\right|>\mathrm{Uzd}$

To sum up, voltage transformer disconnection criterion is obtained as follows:

The line voltage magnitude relation of two voltage transformer (VT) utilizing the protection of pumped-storage power generation machine to connect judges voltage transformer disconnection.When line voltage corresponding to two voltage transformer (VT) difference in magnitude any one be greater than setting valve time, then think and occur that PT is with no pressure, outlet PT breaks.

Described setting valve is determined according to detected voltage transformer secondary side load symmetric case, generally gets 0.15 ~ 0.3 times of rated voltage, and in engineering, the best rounds definite value is 0.15 times of rated voltage.

This practicality invention does not relate to the part prior art that maybe can adopt all same as the prior art and is realized.

Claims (5)

1. the detection method of a voltage transformer disconnection; in hydroenergy storage station, generator protection voltage transformer (VT) is two; comprise the voltage transformer (VT) one in generating direction and the voltage transformer (VT) two in direction of drawing water, it is characterized in that the detection method of voltage transformer disconnection comprises the steps:

(1), from voltage transformer (VT) one PT1 gather voltage signal, and obtain line voltage U by calculating ¹ _aB, U ¹ _bC, U ¹ _cA;

(2), from voltage transformer (VT) two PT2 gather voltage signal, and obtain line voltage U by calculating ² _aB, U ² _bC, U ² _cA;

(3), compare the relation of two each line voltage magnitudes of voltage transformer (VT), namely calculate the line voltage amplitude value difference △ U of two voltage transformer (VT) _aB, △ U _bCwith △ U _cA, judge whether voltage transformer (VT) breaks;

In step (3), △ U _aB, △ U _bCwith △ U _cAcalculation procedure be specially:

To line voltage U ¹ _aBcalculate vector R _1AB+ JX _1AB, calculate U according to vector meter ¹ _aBamplitude:

$\left|{U^1}_{AB}\right|=\sqrt{R_{1AB}^2+X_{1AB}^2}$

To line voltage U ² _aBcalculate vector formulas R _2AB+ JX _2AB, calculate U according to vector meter ² _aBamplitude:

$\left|{U^2}_{AB}\right|=\sqrt{R_{2AB}^2+X_{2AB}^2}$

Obtain, △ U _aB=︱ ︱ U ¹ _aB︱-︱ U ² _aB︱ ︱

In like manner, △ U _bC=︱ ︱ U ¹ _bC︱-︱ U ² _bC︱ ︱

△U _CA＝︱︱U ¹ _CA︱-︱U ² _CA︱︱；

Broken string situation specifically judges as follows:

A, three-phase break: when broken string all occurs PT1 three-phase, U ¹ _aB, U ¹ _bC, U ¹ _cAamplitude be zero, △ U _aB, △ U _bC, △ U _cAall be greater than Uzd;

B, two-phase break: when broken string occurs PT1B, C phase, U ¹ _band U ¹ _cbe equal to 0, as calculated, show that the line voltage of PT1 is: ︱ U ¹ _aB︱=︱ U ¹ _a︱, ︱ U ¹ _bC︱=0, ︱ U ¹ _cA︱=︱ U ¹ _a︱; Namely the maximum line voltage of PT1 is identical with former phase voltage amplitude, and the minimum amplitude of line voltage is 0;

${\mathrm{\ΔU}}_{AB}=\left|\right|{U^1}_A|-|{U^2}_{AB}\left|\right|=(\sqrt{3}-1)\left|{U^1}_A\right|>Uzd$

${\mathrm{\ΔU}}_{BC}=\left|{U^2}_{BC}\right|=\sqrt{3}\left|{U^1}_A\right|>Uzd$

${\mathrm{\ΔU}}_{CA}=\left|\right|{U^1}_A|-|{U^2}_{CA}\left|\right|=(\sqrt{3}-1)\left|{U^1}_A\right|>Uzd$

C, single-phase wire break: when broken string occurs PT1A phase, U ¹ _aequal 0, as calculated, show that the line voltage of PT1 is: ︱ U ¹ _aB︱=︱ U ¹ _b︱, ︱ U ¹ _bC︱=︱ U ¹ _bC︱, ︱ U ¹ _cA︱=︱ U ¹ _c︱; Namely the maximum line voltage of PT1 is identical with former line voltage magnitude, and the minimum amplitude of line voltage is identical with former phase voltage amplitude;

${\mathrm{\ΔU}}_{AB}=\left|\right|{U^1}_B|-|{U^2}_{BA}\left|\right|=(\sqrt{3}-1)\left|{U^1}_B\right|>Uzd$

△U _BC＝︱︱U ¹ _BC︱-︱U ² _BC︱︱＝0

${\mathrm{\ΔU}}_{CA}=\left|\right|{U^1}_C|-|{U^2}_{CA}\left|\right|=(\sqrt{3}-1)\left|{U^1}_B\right|>Uzd.$

2. the detection method of voltage transformer disconnection according to claim 1, it is characterized in that: the relation comparing two each line voltage magnitudes of voltage transformer (VT), when line voltage corresponding to two voltage transformer (VT) difference in magnitude any one be greater than setting valve Uzd time, then judge voltage transformer (VT) occur broken string.

3. the detection method of voltage transformer disconnection according to claim 2, is characterized in that: described setting valve Uzd determines according to detected voltage transformer secondary side load symmetric case, 0.15 ~ 0.3 times that gets voltage transformer (VT) rated voltage.

4. the detection method of voltage transformer disconnection according to claim 3, is characterized in that: setting valve Uzd gets 0.15 times of voltage transformer (VT) rated voltage.

5. the detection method of voltage transformer disconnection according to claim 1, is characterized in that: gathering voltage signal from voltage transformer (VT) one, two is phase voltage, after filtering circuit, convert digital quantity signal to by analog signals, obtains line voltage U as calculated ¹ _aB, U ¹ _bC, U ¹ _cAand U ² _aB, U ² _bC, U ² _cA.