CN106597272A - Two-level STATCOM switch device open circuit fault positioning method - Google Patents

Abstract

The invention relates to a two-level STATCOM switch device open circuit fault positioning method and belongs to fault diagnosis field of an inverter switch device. Switch device open circuit faults comprise two types of IGBT open circuit and freewheeling diode open circuit. According to the method, an STATCOM three-phase output current il(k) ( l belongs to a, b and c) and a network side three-phase voltage ul(k) (l belongs to a, b and c) are acquired, a three-phase compensation current positive and negative half wave reactive power with an expression described as specification is calculated, the three-phase compensation current positive and negative half wave reactive power is normalized to acquire an expression described as specification to take as a fault characteristic, and a fault location phase can be positioned through comparing the fault characteristic with set thresholds alpha and beta; a fault phase current is re-extracted to calculate a 1/4-period reactive power difference dlx ( the x can be 0 or 1, and the l belongs to a, b and c), and the reactive power difference dlx is compared with a set threshold gamma to further position IGBT open circuit or freewheeling diode open circuit. The method is advantaged in that a problem that IGBT open circuit and freewheeling diode open circuit faults can not be distinguished through a diagnosis method in the prior art is solved, IGBT and diode fault positions can be effectively and precisely positioned, and the method is further not influenced by load fluctuation.

Description

Two level STATCOM switching device open fault localization methods

Technical field

The present invention relates to a kind of two level STATCOMs switching device open fault localization method, belongs to fault of converter and examines Disconnected field.

Background technology

Inverter application in the industrial production is more and more extensive.Inverter must use the power of high switching frequency and open Close device.According to a statistics investigated more than 200 parts from 80 companies, power device failure occupies the 60% of frequency converter failure More than, therefore fault power device is quickly positioned, it is most important for inverter.

There are many power device of inverter method for diagnosing faults at present, such as PARK the most commonly used with current detecting Vector method, current phasor method of loci etc..But these methods are only suitable for and frequency conversion speed-adjusting system, are not suitable for STATCOM (static Synchronous compensator), reason is because that frequency conversion speed-adjusting system its exchange side joint is motor, belongs to inductive load.But for STATCOM, under being operated in perception and two kinds of operating modes of capacitive, therefore the reliability of these determination methods is difficult to ensure that.Power switch Device open fault includes IGBT open circuits and fly-wheel diode two classes of open circuit, due to upper pipe IGBT and the electric current side of down tube diode To consistent all the time, therefore the above-mentioned diagnostic method based on the magnitude of current cannot also further discriminate between the open fault of IGBT and diode. Therefore power device breakdown judge difficulty is very big, is worth research.

The content of the invention

For the weak point in above-mentioned technology, there is provided a kind of step is simple, two level of accurate positioning efficiency high STATCOM switching device open fault localization methods.

To realize above-mentioned technical purpose, the two level STATCOM switching device open fault localization methods of the present invention, including Following steps：

Analog signalses on step one, two level STATCOM switching devices of collection, are gathered using current transformer STATCOM three-phase output currents i_lK (), (l ∈ (a, b, c)) gathers AC electrical network three-phase voltage u using transformer_l(k),(l ∈ (a, b, c)), wherein i_l(k) for STATCOM l phase output currents, u_lK () is and i_lThe k phase net side that () is sampled in the same time Voltage；

Step 2, the detection cycle of every phase l (l ∈ (a, b, c)) voltage on line side for obtaining is divided into into four areas Between：Interval I, interval II, interval III, interval IV, the three-phase voltage on line side in four intervals matches respectively with three-phase output current, Obtain and four interval reactive power Qs corresponding respectively of three-phase voltage on line side_lI、Q_lII、Q_lIII、Q_lIV, using three-phase voltage on line side Four interval reactive power Qs corresponding respectively_lI、Q_lII、Q_lIII、Q_lIVObtain the three-phase positive half-wave of STATCOM major loops switch Reactive power Q_l ⁺With the reactive power Q of the negative half-wave of three-phase_l ^-；

The reactive power Q of step 3, the positive and negative half-wave of three-phase switched according to STATCOM major loops_l ⁺,Q_l ^-Extract failure special Value indicative S_l ^m, the 6 fault eigenvalue S for obtaining_l ^mThe working condition of an IGBT or diode is all corresponded to respectively；

6 characteristic values S that step 4, basis are obtained_l ^mFailure judgement place phase, when 6 characteristic values S_l ^mAny feature value goes out When now in default threshold interval, then by occurring in characteristic value S in threshold interval_l ^mJudge the corresponding phase of current characteristic value Failure, otherwise return to step one；

Step 5, using the reactive power Q in four intervals of a detection cycle_lI、Q_lII、Q_lIII、Q_lIVCalculate failure phase l electricity Flow 1/4 cycle reactive power difference d_lx(x=0,1；L ∈ (a, b, c)), 1/4 cycle of the electric current reactive power using failure phase l is poor d_lx(x=0,1；L ∈ (a, b, c)) determine whether the IGBT open circuits in specifically failure phase or fly-wheel diode open circuit event Barrier.

Four intervals that a detection cycle per phase l (l ∈ (a, b, c)) voltage on line side is divided into, respectively net side The interval I of 90～180 degree of voltage-phase, 180～270 degree of interval II, 270～360 degree of interval III, 0～90 degree of interval IV。

The reactive power Q of the three-phase positive half-wave_l ⁺With the reactive power Q of the negative half-wave of three-phase_l ^-By formula：Obtain, and reactive powers of the STATCOM per mutually positive and negative half-wave is calculated using equation below：

In formula：K is collection AC electrical network three-phase voltage u_l(k), k-th sampled point of (l ∈ (a, b, c)), i_l(k),(l ∈ (a, b, c)) be and three-phase voltage u_l(k), the three-phase electricity flow valuve that (l ∈ (a, b, c)) samples in the same time, each periodic sampling point Number is N, is 4 multiple；

The fault eigenvalue S_l ^mUsing formula：With

It is calculated 6 fault eigenvalue S_l ^mOne is all corresponded to respectively The working condition of IGBT or diode, wherein m are to distinguish the characteristic quantity of upper and lower switching tube, i.e. m=+, S_l ⁺In correspondence pipe IGBT and Down tube diode；In the same manner, m=-, S_l ^-Correspondence down tube IGBT and upper pipe diode.

The setting fault eigenvalue S_l ^mThreshold alpha=0.2 of failure judgement place phase, β=- 0.2, when meeting β<S_l ^m<α During condition, l (l ∈ (a, b, c)) phase fault is judged；

When fault-free, 6 fault eigenvalue S_l ^mValue perceptual operating mode lower aprons be 1, fault eigenvalue S_l Capacitive operating mode lower aprons are -1；During generation switch tube open circuit, the corresponding fault eigenvalue S of the switching tube_l ^mValue close 0, therefore, In order to ensure as little as possible, but mistaken diagnosis of less threshold value when can cause load changing again that correctness should be arranged threshold value, The threshold value arranged using this method, diagnostic method is not being affected by load changing.

If -0.2<S_l ⁺<0, two level STATCOM switching devices are judged now for capacitive operating mode, pipe IGBT or down tube in l phases Fly-wheel diode is opened a way；If -0.2<S_l ^-<0, two level STATCOM switching devices are judged now for capacitive operating mode, l phase down tubes IGBT or upper pipes fly-wheel diode is opened a way；If 0<S_l ⁺<0.2, two level STATCOM switching devices are judged now for perceptual operating mode, l Pipe IGBT or down tube fly-wheel diode are opened a way in phase；If

0<S_l ^-<0.2, two level STATCOM switching devices are judged now for perceptual operating mode, l phases down tube IGBT or upper Guan Xu Stream diode open-circuit.

Using formula：Calculate failure phase l 1/4 cycle of electric current reactive power difference d_lx(x=0,1；l∈(a, B, c)), and for reactive power difference d_lxPerceptual capacitive threshold gamma=0 of threshold interval setting, using following table：

To determine whether that IGBT opens a way or fly-wheel diode open circuit completes diagnosis.

Beneficial effect：Three-phase output current and electricity that the application passes through collection STATCOM major loop switching device Pressure signal, and reactive power is obtained by three-phase output current and voltage signal, obtain fault eigenvalue using reactive power and lead to The threshold interval for crossing fault eigenvalue judges the failure original paper of STATCOM major loop switching device, and step is simple, Accurate efficiency high is detected, is not affected by load changing, reliability is high, solves existing method and is difficult to differentiate between IGBT and diode A difficult problem for open fault

Description of the drawings

Fig. 1 is the level STATCOM electric topology figure of three-phase four-wire system two of the present invention.

When Fig. 2 is pipe diode open-circuit in the generation a phases of the present invention, characteristic value F_l ^mWith the curve map of rate of load condensate.

When Fig. 3 is that generation a phases down tube IGBT of the present invention is opened a way, characteristic value F_l ^mWith the curve map of rate of load condensate.

Fig. 4 is under the perceptual operating mode of the present invention, diode open-circuit in a phases occurs, and during upper pipe IGBT open circuits, d_a1With load The curve map of rate.

Fig. 5 is under the capacitive operating mode of the present invention, diode open-circuit in a phases occurs, and during upper pipe IGBT open circuits, d_a0With load The curve map of rate.

Fig. 6 is the inventive method flow chart.

Specific embodiment

One embodiment is described further below in conjunction with the accompanying drawings：

As shown in figures 1 to 6, two level STATCOM switching device open fault localization methods of the invention, it include with Lower step：

Analog signalses on step one, two level STATCOM switching devices of collection, are gathered using current transformer STATCOM three-phase output currents i_lK (), (l ∈ (a, b, c)) gathers AC electrical network three-phase voltage u using transformer_l(k),(l ∈ (a, b, c)), wherein i_l(k) for STATCOM l phase output currents, u_lK () is and i_lThe k phase net side that () is sampled in the same time Voltage；

Step 2, the detection cycle of every phase l (l ∈ (a, b, c)) voltage on line side for obtaining is divided into into four areas Between, four intervals are respectively the interval I of voltage on line side 90～180 degree of phase place, 180～270 degree of interval II, 270～360 The interval III of degree, 0～90 degree of interval IV, the three-phase voltage on line side in four intervals matches respectively with three-phase output current, obtains Obtain and four interval reactive power Qs corresponding respectively of three-phase voltage on line side_lI、Q_lII、Q_lIII、Q_lIV, using three-phase voltage on line side four Individual interval reactive power Q corresponding respectively_lI、Q_lII、Q_lIII、Q_lIVObtain the nothing of the three-phase positive half-wave of STATCOM major loops switch Work(power Q_l ⁺With the reactive power Q of the negative half-wave of three-phase_l ^-；The reactive power Q of the three-phase positive half-wave_l ⁺With the nothing of the negative half-wave of three-phase Work(power Q_l ^-By formula：Obtain, and nothings of the STATCOM per mutually positive and negative half-wave is calculated using equation below Work(power：

In formula：K is collection AC electrical network three-phase voltage u_l(k), k-th sampled point of (l ∈ (a, b, c)), i_l(k),(l ∈ (a, b, c)) be and three-phase voltage u_l(k), the three-phase electricity flow valuve that (l ∈ (a, b, c)) samples in the same time, each periodic sampling point Number is N, is 4 multiple；

The reactive power Q of step 3, the positive and negative half-wave of three-phase switched according to STATCOM major loops_l ⁺,Q_l ^-Extract failure special Value indicative S_l ^m, the 6 fault eigenvalue S for obtaining_l ^mThe working condition of an IGBT or diode is all corresponded to respectively；

6 characteristic values S that step 4, basis are obtained_l ^mFailure judgement place phase, when 6 characteristic values S_l ^mAny feature value goes out When now in default threshold interval, then by occurring in characteristic value S in threshold interval_l ^mJudge the corresponding phase of current characteristic value Failure, otherwise return to step one；

Step 5, using the reactive power Q in four intervals of a detection cycle_lI、Q_lII、Q_lIII、Q_lIVCalculate failure phase l electricity Flow 1/4 cycle reactive power difference d_lx(x=0,1；L ∈ (a, b, c)), 1/4 cycle of the electric current reactive power using failure phase l is poor d_lx(x=0,1；L ∈ (a, b, c)) determine whether the IGBT open circuits in specifically failure phase or fly-wheel diode open circuit event Barrier.

The fault eigenvalue S_l ^mUsing formula：With

It is calculated 6 fault eigenvalue S_l ^mOne is all corresponded to respectively The working condition of IGBT or diode, wherein m are to distinguish the characteristic quantity of upper and lower switching tube, i.e. m=+, S_l ⁺In correspondence pipe IGBT and Down tube diode；In the same manner, m=-, S_l ^-Correspondence down tube IGBT and upper pipe diode.

As shown in Figures 2 and 3, the setting fault eigenvalue S_l ^mThreshold alpha=0.2 of failure judgement place phase, β=- 0.2, when meeting β<S_l ^m<During α conditions, l (l ∈ (a, b, c)) phase fault is judged；

When fault-free, 6 fault eigenvalue S_l ^mValue perceptual operating mode lower aprons be 1, fault eigenvalue S_l Capacitive operating mode lower aprons are -1；During generation switch tube open circuit, the corresponding fault eigenvalue S of the switching tube_l ^mValue close 0, therefore, In order to ensure as little as possible, but mistaken diagnosis of less threshold value when can cause load changing again that correctness should be arranged threshold value, The threshold value arranged using this method, diagnostic method is not being affected by load changing.

If -0.2<S_l ⁺<0, two level STATCOM switching devices are judged now for capacitive operating mode, pipe IGBT or down tube in l phases Fly-wheel diode is opened a way；If -0.2<S_l ^-<0, two level STATCOM switching devices are judged now for capacitive operating mode, l phase down tubes IGBT or upper pipes fly-wheel diode is opened a way；If 0<S_l ⁺<0.2, two level STATCOM switching devices are judged now for perceptual operating mode, l Pipe IGBT or down tube fly-wheel diode are opened a way in phase；If

0<S_l ^-<0.2, two level STATCOM switching devices are judged now for perceptual operating mode, l phases down tube IGBT or upper Guan Xu Stream diode open-circuit.

Such as Fig. 4 and Fig. 5, using formula：Calculate failure phase l 1/4 cycle of electric current reactive power difference d_lx(x =0,1；L ∈ (a, b, c)), and for reactive power difference d_lxPerceptual capacitive threshold gamma=0 of threshold interval setting, using following table：

To determine whether that IGBT opens a way or fly-wheel diode open circuit completes diagnosis.

Claims (7)

1. a kind of two level STATCOMs switching device open fault localization method, it is characterised in that comprise the following steps：

Analog signalses on step one, two level STATCOM switching devices of collection, using current transformer STATCOM is gathered Three-phase output current i_lK (), (l ∈ (a, b, c)) gathers AC electrical network three-phase voltage u using transformer_l(k),(l∈(a,b, C)), wherein i_l(k) for STATCOM l phase output currents, u_lK () is and i_lThe k phase voltage on line side that () is sampled in the same time；

Step 2, the detection cycle of every phase l (l ∈ (a, b, c)) voltage on line side for obtaining is divided into into four intervals：Area Between I, interval II, interval III, interval IV, the three-phase voltage on line side in four intervals matches respectively with three-phase output current, obtains With four interval reactive power Qs corresponding respectively of three-phase voltage on line side_lI、Q_lII、Q_lIII、Q_lIV, using three-phase voltage on line side four The corresponding reactive power Q of interval difference_lI、Q_lII、Q_lIII、Q_lIVObtain the idle of the three-phase positive half-wave that STATCOM major loops are switched Power Q_l ⁺With the reactive power Q of the negative half-wave of three-phase_l ^-；

The reactive power Q of step 3, the positive and negative half-wave of three-phase switched according to STATCOM major loops_l ⁺,Q_l ^-Extract fault eigenvalue S_l ^m, the 6 fault eigenvalue S for obtaining_l ^mThe working condition of an IGBT or diode is all corresponded to respectively；

6 characteristic values S that step 4, basis are obtained_l ^mFailure judgement place phase, when 6 characteristic values S_l ^mAny feature value is occurred in When in default threshold interval, then by occurring in characteristic value S in threshold interval_l ^mJudge the corresponding phase event of current characteristic value Barrier, otherwise return to step one；

Step 5, using the reactive power Q in four intervals of a detection cycle_lI、Q_lII、Q_lIII、Q_lIVCalculate failure phase l electric current 1/ 4 cycle reactive power difference d_lx(x=0,1；L ∈ (a, b, c)), using 1/4 cycle of the electric current reactive power difference d of failure phase l_lx(x =0,1；L ∈ (a, b, c)) determine whether that the IGBT in specifically failure phase opens a way or fly-wheel diode open fault.

2. two level STATCOM switching device open fault localization methods according to claims 1, it is characterised in that： Four intervals that a detection cycle per phase l (l ∈ (a, b, c)) voltage on line side is divided into, respectively voltage on line side phase place The interval I of 90～180 degree, 180～270 degree of interval II, 270～360 degree of interval III, 0～90 degree of interval IV.

3. two level STATCOM switching device open fault localization methods according to claims 1, it is characterised in that： The reactive power Q of the three-phase positive half-wave_l ⁺With the reactive power Q of the negative half-wave of three-phase_l ^-By formula：Obtain, And calculate reactive powers of the STATCOM per mutually positive and negative half-wave using equation below：

In formula：K is collection AC electrical network three-phase voltage u_l(k), k-th sampled point of (l ∈ (a, b, c)), i_l(k),(l∈ (a, b, c)) be and three-phase voltage u_l(k), the three-phase electricity flow valuve that (l ∈ (a, b, c)) samples in the same time, each periodic sampling points It is 4 multiple for N.

4. two level STATCOM switching device open fault localization methods according to claims 1, it is characterised in that institute State fault eigenvalue S_l ^mUsing formula：With It is calculated 6 fault eigenvalue S_l ^mThe working condition of an IGBT or diode is all corresponded to respectively, and wherein m is opened up and down to distinguish Close the characteristic quantity of pipe, i.e. m=+, S_l ⁺Pipe IGBT and down tube diode in correspondence；In the same manner, m=-, S_l ^-Correspondence down tube IGBT and upper Pipe diode.

5. two level STATCOM switching device open fault localization methods according to claims 1, it is characterised in that： The setting fault eigenvalue S_l ^mThreshold alpha=0.2 of failure judgement place phase, β=- 0.2, when meeting β<S_l ^m<During α conditions, sentence Determine l (l ∈ (a, b, c)) phase fault；

When fault-free, 6 fault eigenvalue S_l ^mValue perceptual operating mode lower aprons be 1, fault eigenvalue S_lIn capacitive Operating mode lower aprons are -1；During generation switch tube open circuit, the corresponding fault eigenvalue S of the switching tube_l ^mValue close 0, therefore, in order to Ensure as little as possible, but mistaken diagnosis of less threshold value when can cause load changing again that correctness should be arranged threshold value, use The threshold value that this method is arranged, diagnostic method is not being affected by load changing.

6. two level STATCOM switching device open fault localization methods according to claims 5, it is characterised in that： If -0.2<S_l ⁺<0, two level STATCOM switching devices are judged now for capacitive operating mode, pipe IGBT or the pole of down tube afterflow two in l phases Tube open circuit；If -0.2<S_l ^-<0, two level STATCOM switching devices are judged now for capacitive operating mode, l phases down tube IGBT or upper pipe Fly-wheel diode is opened a way；If 0<S_l ⁺<0.2, two level STATCOM switching devices are judged now for perceptual operating mode, pipe IGBT in l phases Or down tube fly-wheel diode open circuit；If 0<S_l ^-<0.2, judge two level STATCOM switching devices now for perceptual operating mode, under l phases Pipe IGBT or upper pipes fly-wheel diode is opened a way.

7. two level STATCOM switching device open fault localization methods according to claims 6, it is characterised in that profit Use formula：Calculate failure phase l 1/4 cycle of electric current reactive power difference d_lx(x=0,1；L ∈ (a, b, c)), and be Reactive power difference d_lxPerceptual capacitive threshold gamma=0 of threshold interval setting, using following table：

To determine whether that IGBT opens a way or fly-wheel diode open circuit completes diagnosis.