CN105762771A - Circuit breaker non full phase judging method based on two-side voltage fundamental wave amplitude ratio - Google Patents

Abstract

The invention discloses a circuit breaker non full phase judging method based on a two-side voltage fundamental wave amplitude ratio. A protection device is used for measuring three-phase voltage and open delta voltage at the left side and the right side of the circuit breaker; fundamental wave amplitudes of the three-phase voltage and the open delta voltage at the left side and the right side of the circuit breaker and the ratio of the fundamental wave amplitudes of the open delta voltage at the left side and the right side are calculated respectively; when the fundamental wave amplitudes of the three-phase voltage at the left side and the right side are both larger than eta% of rated voltage, when the fundamental wave amplitudes of the open delta voltage at the left side and the right side are both larger than a fundamental wave amplitude threshold, and when the fundamental wave amplitude ratio of the open delta voltage at the left side and the right side is larger than a ratio fixed value threshold, circuit breaker non full phase is judged, and alarming or tripping is carried out after a short time delay t. The method does not rely on the magnitude of negative-sequence current and solves the problem that when non full phase happens to the circuit breaker in the case of light load and the previous negative sequence current criterion can not be recognized; and in addition, as the method does not need to judge a three-phase inconsistent contact of the circuit breaker, the non-full phase judging problem of a three-phase linked circuit breaker can also be solved.

Description

Chopper non-three phase determination methods based on both sides voltage fundamental amplitude ratio

Technical field

The invention belongs to field of relay protection in power, particularly to a kind of chopper non-three phase determination methods based on both sides voltage fundamental amplitude ratio.

Background technology

At present, on-the-spot wide variety of chopper non-whole phase protection is generally collectively formed by unbalanced three-phase lines contact and negative sequence current criterion, when light running operating mode; owing to phase current is only small; during chopper non-three phase, negative-sequence current is only small, it is difficult to exceed negative-sequence current definite value, it is impossible to judge chopper non-three phase.Generator end chopper is generally three-phase ganged; unbalanced three-phase lines contact is not provided; tradition non-whole phase protection cannot be adopted; on-the-spot repeatedly occur that the fracture of machine end chopper one phase pull bar causes the accident of non-three phase; owing to there is no non-whole phase protection; cause that unit bears negative-sequence current for a long time, the safety of electromotor is constituted a threat to.In view of the above deficiency that conventional circuit breaker non-whole phase protection exists, it is necessary to study a kind of chopper non-three phase method of discrimination being independent of size of current and unbalanced three-phase lines contact.

Summary of the invention

The main purpose of the present invention: a kind of chopper non-three phase determination methods based on both sides voltage fundamental amplitude ratio is provided, the method is independent of negative-sequence current size, solve chopper generation non-three phase during underloading, the problem of conventional negative sequence current criterion None-identified, in addition, owing to the method need not judge chopper unbalanced three-phase lines contact, also solve the non-three phase discrimination of three-phase ganged chopper.

Theory analysis shows, during chopper non-three phase, the situation that fundamental voltage amplitude is inconsistent occurs in the open delta voltage of port both sides, and therefore, the fundamental voltage amplitude ratio of chopper both-side opening triangular voltages can be used for judging non-three phase.

The technical solution adopted in the present invention is:

A kind of chopper non-three phase determination methods based on both sides voltage fundamental amplitude ratio, it is characterized in that: use three-phase voltage and the open delta voltage of the protector measuring chopper left and right sides, calculate chopper left and right sides three-phase voltage respectively, the fundamental voltage amplitude of open delta voltage and the ratio of left and right sides open delta voltage fundamental voltage amplitude, when the fundamental voltage amplitude of left and right sides three-phase voltage is all higher than the η % of rated voltage, the fundamental voltage amplitude of left and right sides open delta voltage is all higher than fundamental voltage amplitude threshold simultaneously, and when the fundamental voltage amplitude ratio of left and right sides open delta voltage is more than ratio definite value threshold, it is judged to chopper non-three phase, through too short time delay t action in reporting to the police or tripping operation.

Preferably, the three-phase voltage of protector measuring chopper both sides, open delta voltage, both sides three-phase voltage, open delta voltage are taken from the threephase potential transformer of chopper both sides.

Preferably, the calculating of the fundamental voltage amplitude of the fundamental voltage amplitude of chopper left and right sides three-phase voltage, open delta voltage all adopts all-round fourier algorithm；

Wherein the fundamental voltage amplitude computing formula of left and right sides phase voltage is as follows:

$\left\{\begin{array}{c}{U}_{\mathrm{\φ}.\mathrm{Re}}=\frac{2}{N}\underset{k=0}{\overset{N-1}{\Σ}}{u}_{\mathrm{\φ}}\left(k\right)cos\left(\frac{2\mathrm{\π}k}{N}\right)\\ U_{\mathrm{\φ}.\mathrm{Im}}=-\frac{2}{N}\underset{k=0}{\overset{N-1}{\Σ}}{u}_{\mathrm{\φ}}\left(k\right)sin\left(\frac{2\mathrm{\π}k}{N}\right)\\ U_{\mathrm{\φ}.AM}=\sqrt{U_{\mathrm{\φ}.\mathrm{Re}}^2+U_{\mathrm{\φ}.\mathrm{Im}}^2}\end{array}\right.,$ φ=a, b, c or A, B, C formula (2)

Wherein, N is the sampling number of the protection each power frequency period of device, U_φ.Re、U_φ.ImThe respectively real part of the fundamental phasors of phase voltage and imaginary part, U_φ.AMFor the fundamental voltage amplitude of phase voltage, u_φK () is phase voltage instantaneous sampling value, φ takes a, b, c or A, B, C and represents the A phase of m side or n side, B phase, C phase respectively；

And the fundamental voltage amplitude computing formula of both-side opening triangular voltages is as follows:

$\left\{\begin{array}{c}{U}_{\mathrm{\ψ}0.\mathrm{Re}}=\frac{2}{N}\underset{k=0}{\overset{N-1}{\Σ}}{u}_0\left(k\right)cos\left(\frac{2\mathrm{\π}k}{N}\right)\\ U_{\mathrm{\ψ}0.\mathrm{Im}}=-\frac{2}{N}\underset{k=0}{\overset{N-1}{\Σ}}{u}_0\left(k\right)sin\left(\frac{2\mathrm{\π}k}{N}\right)\\ 3U_{\mathrm{\ψ}0}=\sqrt{U_{\mathrm{\ψ}0.\mathrm{Re}}^2+U_{\mathrm{\ψ}0.\mathrm{Im}}^2}\end{array}\right.$ Formula (3)

Wherein, N is the sampling number of the protection each power frequency period of device, U_ψ0.Re、U_ψ0.ImThe respectively real part of the fundamental phasors of open delta voltage and imaginary part, 3U_ψ0For the fundamental voltage amplitude of open delta voltage, ψ takes m, n and represents m side, n side, u respectively₀K () is open delta voltage instantaneous sampling value.

Preferably, protection device is through too short time delay t action in reporting to the police or tripping operation, and the span of t is 0.1 second～10 seconds.

The invention has the beneficial effects as follows: the size of negative-sequence current need not be judged, solve chopper generation non-three phase during underloading, the problem of tradition negative sequence current criterion None-identified non-three phase；Owing to unbalanced three-phase lines contact need not be judged, it is equally applicable to the chopper of three-phase ganged, and conventional non-whole phase protection principle cannot judge three-phase ganged chopper non-three phase.

Accompanying drawing explanation

Port both sides three-phase voltage instrumentation plan when Fig. 1 is chopper non-three phase in the present invention, in figure, G is electromotor, and S is Infinite bus system, and BG is generator side bus, and BS is system side bus, on the left of m, n respectively breaker port and right side, TV_mFor the voltage transformer of chopper m side, TV_nFor the voltage transformer of chopper n side, U_a、U_bAnd U_cFor the three-phase voltage of m side, U_A、U_BAnd U_CFor the three-phase voltage of n side, 3U_m0For m side opening triangular voltages, 3U_n0For n side opening triangular voltages.

Detailed description of the invention

Below with reference to accompanying drawing, technical scheme is described in detail.

In FIG, measure both sides three-phase voltage respectively from the TV of breaker port both sides, adopt all-round fourier algorithm to calculate the fundamental voltage amplitude of both sides voltage.

The fundamental voltage amplitude computing formula of two sides TV phase voltage is as follows:

$\left\{\begin{array}{c}{U}_{\mathrm{\φ}.\mathrm{Re}}=\frac{2}{N}\underset{k=0}{\overset{N-1}{\Σ}}{u}_{\mathrm{\φ}}\left(k\right)cos\left(\frac{2\mathrm{\π}k}{N}\right)\\ U_{\mathrm{\φ}.\mathrm{Im}}=-\frac{2}{N}\underset{k=0}{\overset{N-1}{\Σ}}{u}_{\mathrm{\φ}}\left(k\right)sin\left(\frac{2\mathrm{\π}k}{N}\right)\\ U_{\mathrm{\φ}.AM}=\sqrt{U_{\mathrm{\φ}.\mathrm{Re}}^2+U_{\mathrm{\φ}.\mathrm{Im}}^2}\end{array}\right.,$ φ=a, b, c or A, B, C formula (1)

Wherein, N is the sampling number of the protection each power frequency period of device, U_φ.Re、U_φ.ImThe respectively real part of the fundamental phasors of phase voltage and imaginary part, U_φ.AMFor the fundamental voltage amplitude of phase voltage, u_φK () is phase voltage instantaneous sampling value, φ can take a, b, c or A, B, C and represent A phase, B phase, C phase respectively.

The fundamental voltage amplitude computing formula of two sides TV open delta voltage is as follows:

$\left\{\begin{array}{c}{U}_{\mathrm{\ψ}0.\mathrm{Re}}=\frac{2}{N}\underset{k=0}{\overset{N-1}{\Σ}}{u}_0\left(k\right)cos\left(\frac{2\mathrm{\π}k}{N}\right)\\ U_{\mathrm{\ψ}0.\mathrm{Im}}=-\frac{2}{N}\underset{k=0}{\overset{N-1}{\Σ}}{u}_0\left(k\right)sin\left(\frac{2\mathrm{\π}k}{N}\right)\\ 3U_{\mathrm{\ψ}0}=\sqrt{U_{\mathrm{\ψ}0.\mathrm{Re}}^2+U_{\mathrm{\ψ}0.\mathrm{Im}}^2}\end{array}\right.$ Formula (2)

Wherein, N is the sampling number of the protection each power frequency period of device, U_ψ0.Re、U_ψ0.ImThe respectively real part of the fundamental phasors of open delta voltage and imaginary part, 3U_ψ0For the fundamental voltage amplitude of open delta voltage, ψ can take m, n and represent m side, n side, u respectively₀K () is open delta voltage instantaneous sampling value.

Chopper non-three phase criterion is:

Formula (3)

Wherein, being "AND" logic between each criterion of above formula, m is the left side that breaker port is connected with electromotor, and n is the right side that breaker port is connected with Infinite bus system, U_a.AM、U_b.AM、U_c.AMRespectively chopper m side A phase voltage, B phase voltage, C phase voltage fundamental voltage amplitude, U_A.AM、U_B.AM、U_C.AMRespectively chopper n side A phase voltage, B phase voltage, C phase voltage fundamental voltage amplitude,For specified phase voltage, 3U_m0、3U_n0Respectively m side and n side opening triangular voltages fundamental voltage amplitude, 3U_0setFor open delta voltage fundamental voltage amplitude threshold, k_setFor ratio definite value threshold, k_setBeing 0.5～20, η generally takes 60～90, and min represents the minima taking two numerical value.

Above example is only the technological thought that the present invention is described, it is impossible to limits protection scope of the present invention, every technological thought proposed according to the present invention, any change done on technical scheme basis with this, each falls within scope.

Claims (5)

1. the chopper non-three phase determination methods based on both sides voltage fundamental amplitude ratio, it is characterized in that: use three-phase voltage and the open delta voltage of the protector measuring chopper left and right sides, calculate chopper left and right sides three-phase voltage respectively, the fundamental voltage amplitude of open delta voltage and the ratio of left and right sides open delta voltage fundamental voltage amplitude, when the fundamental voltage amplitude of left and right sides three-phase voltage is all higher than the η % of rated voltage, the fundamental voltage amplitude of left and right sides open delta voltage is all higher than fundamental voltage amplitude threshold simultaneously, and when the fundamental voltage amplitude ratio of left and right sides open delta voltage is more than ratio definite value threshold, it is judged to chopper non-three phase, through too short time delay t action in reporting to the police or tripping operation.

2. the chopper non-three phase determination methods based on both sides voltage fundamental amplitude ratio as claimed in claim 1; it is characterized in that: if meeting the chopper non-three phase criterion described in formula (1); then it is judged to non-three phase, protects device action in reporting to the police or tripping operation through too short time delay t；

Chopper non-three phase criterion is:

Formula (1)

Being "AND" logic between each sub-criterion in formula (1), m is the left side port of chopper, and n is the right side port of chopper, U_a.AM、U_b.AM、U_c.AMRespectively chopper m side A phase voltage, B phase voltage, C phase voltage fundamental voltage amplitude, U_A.AM、U_B.AM、U_C.AMRespectively chopper n side A phase voltage, B phase voltage, C phase voltage fundamental voltage amplitude,For specified phase voltage, 3U_m0、3U_n0Respectively m side, n side opening triangular voltages fundamental voltage amplitude, 3U_0setFor the definite value threshold of open delta voltage fundamental voltage amplitude, k_setFor the definite value threshold of both-side opening triangular voltages fundamental voltage amplitude ratio, k_setSpan be 0.5～20, the span of η is 60～90.

3. the chopper non-three phase determination methods based on both sides voltage fundamental amplitude ratio as claimed in claim 2; it is characterized in that: the three-phase voltage of protector measuring chopper both sides, open delta voltage, both sides three-phase voltage, open delta voltage are taken from the threephase potential transformer of chopper both sides.

4. the chopper non-three phase determination methods based on both sides voltage fundamental amplitude ratio as claimed in claim 2, it is characterised in that: the fundamental voltage amplitude of chopper left and right sides three-phase voltage, open delta voltage the calculating of fundamental voltage amplitude all adopt all-round fourier algorithm；

Wherein the fundamental voltage amplitude computing formula of left and right sides phase voltage is as follows:

Formula (2)

Wherein, N is the sampling number of the protection each power frequency period of device, U_φ.Re、U_φ.ImThe respectively real part of the fundamental phasors of phase voltage and imaginary part, U_φ.AMFor the fundamental voltage amplitude of phase voltage, u_φK () is phase voltage instantaneous sampling value, φ takes a, b, c or A, B, C and represents the A phase of m side or n side, B phase, C phase respectively；

And the fundamental voltage amplitude computing formula of both-side opening triangular voltages is as follows:

$\left\{\begin{array}{c}{U}_{\mathrm{\ψ}0.\mathrm{Re}}=\frac{2}{N}\underset{k=0}{\overset{N-1}{\Σ}}{u}_0\left(k\right)cos\left(\frac{2\mathrm{\π}k}{N}\right)\\ U_{\mathrm{\ψ}0.Im}=-\frac{2}{N}\underset{k=0}{\overset{N-1}{\Σ}}{u}_0\left(k\right)sin\left(\frac{2\mathrm{\π}k}{N}\right)\\ 3U_{\mathrm{\ψ}0}=\sqrt{U_{\mathrm{\ψ}0.\mathrm{Re}}^2+U_{\mathrm{\ψ}0.Im}^2}\end{array}\right.$ Formula (3)

Wherein, N is the sampling number of the protection each power frequency period of device, U_ψ0.Re、U_ψ0.ImThe respectively real part of the fundamental phasors of open delta voltage and imaginary part, 3U_ψ0For the fundamental voltage amplitude of open delta voltage, ψ takes m, n and represents m side, n side, u respectively₀K () is open delta voltage instantaneous sampling value.

5. the chopper non-three phase determination methods based on both sides voltage fundamental amplitude ratio as claimed in claim 2, it is characterised in that: protection device is through too short time delay t action in reporting to the police or tripping operation, and the span of t is 0.1 second～10 seconds.