CN204761327U - Improve angle control circuit that puts off arc of commutation failure of direct current transmission system restorability - Google Patents

Abstract

The utility model provides an improve angle control circuit that puts off arc of commutation failure of direct current transmission system restorability, including non - linear modulation unit, proportional integral unit and the pulse trigger unit that connects gradually, non - linear modulation unit is to the first angle deviation signal modulate that puts off arc of input to the output second angle deviation signal that puts off arc, the second angle deviation signal that puts off arc is received to the proportional integral unit, with self input mark for the third angle deviation signal that puts off arc to computing relay angle controlled quantity, the pulse trigger unit is received and is triggered the angle controlled quantity, and controls the break -make of direct current converter thyristor in view of the above. The utility model has the advantages of can effectively avoid exchanging the commutation failure that the back transverter was clear away to the trouble to direct current active power's recovering with higher speed restraines direct current reactive power's consumption to a certain extent.

Description

Improve the gamma kick circuit of DC transmission system commutation failure restorability

Technical field

The utility model relates to a kind of electric power system control running protection technology, particularly a kind of gamma kick circuit improving DC transmission system commutation failure restorability.

Background technology

DC converter commutation failure (extinguish angle is less than 7 °) can be caused when AC system breaks down, cause power delivery to be interrupted.The reactive power of the active power that usual direct current system is carried and consumption is all very large, therefore after improving AC fault, the restorability of direct current system is significant to the safe and stable operation maintaining alternating current-direct current bulk power grid, and Optimal Control System is economically viable way.

Simulation study and operating experience show, under traditional proportional integral closed-loop control framework, may occur some problems when direct current system is recovered from commutation failure: (1) commutation failure duration is longer, the angle stability problem of receiving-end system is sent in aggravation; (2) after AC fault is removed, there is commutation failure in the converter originally having recovered commutation again, interrupts gaining merit transmitting and causing AC voltage fluctuations, the serious recovery hindering direct current; (3) due to the overshoot of direct current and extinguish angle, during restoration can there is larger dynamic reactive demand in DC converter, increases the risk of receiving end line voltage unstability.Above problem can be alleviated to a certain extent by adjustment DC control strategy or controling parameters.Current most of control and optimize scheme is all for direct current design, and as introduced current limiting low-voltage controlling unit, its major drawbacks is, will delay the recovery of active power while avoiding follow-up commutation failure or reduction direct current reactive power consumption.When considering that direct current system is run, rectifier controls electric current, inverter control extinguish angle, and commutation failure occurs in inverter side, therefore can attempt proposing Optimal improvements to the circuit structure of gamma kick.

Utility model content

The purpose of this utility model is that the shortcoming overcoming prior art is with not enough, there is provided a kind of gamma kick circuit improving DC transmission system commutation failure restorability, this gamma kick circuit effectively reduces converter between direct-current commutation failure duration, the convalescence of avoiding, and commutation failure, acceleration direct current active power are recovered and suppress direct current reactive power consumption again.

The purpose of this utility model can be achieved through the following technical solutions: a kind of gamma kick circuit improving DC transmission system commutation failure restorability, comprising: the non-linear modulation unit connected successively, pi element and pulse-triggered unit;

Non-linear modulation unit is to the first extinguish angle deviation signal γ of input _errmodulate, and export the second extinguish angle deviation signal γ _err2;

Pi element receives the second extinguish angle deviation signal γ _err2, the input variable of self is labeled as the 3rd extinguish angle deviation signal γ _err3, and computing relay angle controlled quentity controlled variable β _γ, described delay angle controlled quentity controlled variable β _γcomputing formula as follows:

$\frac{b_g\left(s\right)}{g_{err3}\left(s\right)}=K+\frac{1}{T_{i}s},---\left(1\right)$

Wherein, s is pull-type operator, and K is proportionality constant, T _ifor integral constant.Constant π deducts delay angle controlled quentity controlled variable β _γobtain trigger angle control amount α;

Pulse-triggered unit receives trigger angle control amount α, and controls the break-make of DC converter thyristor by described trigger angle control amount α.

As preferably, the gamma kick circuit improving DC transmission system commutation failure restorability of the present utility model also comprises: get junior unit, electric current low-pass filter unit, current comparator, voltage low-pass filter unit, voltage comparator, logical AND gate, the differentiator connected successively, pulse generate unit and binary channels selector;

Get an input of the output connected nonlinearity modulating unit of junior unit, electric current low-pass filter unit, current comparator are connected successively with an input of logical AND gate, and voltage low-pass filter unit, voltage comparator are connected successively with another input of logical AND gate; The output of logical AND gate is connected with another input of non-linear modulation unit;

Get junior unit to receive, store and compare the extinguish angle measured value g in 20ms _measand obtain the minimum value of extinguish angle sampled value, by extinguish angle setting value γ _refdeduct the minimum value of extinguish angle sampled value, obtain the first extinguish angle deviation signal γ _err, and the first extinguish angle deviation signal γ _errbe delivered to non-linear modulation unit.

Electric current low-pass filter unit process DC current measures I _dmeas, and output filtering electric current I, adopt following formula to calculate described filtered circuit I:

$\frac{I\left(s\right)}{I_{dmeas}\left(s\right)}=\frac{1}{1+T_{I}s},---\left(2\right)$

Wherein, T _ifor current integration constant, s is laplace operator;

Current comparator accepts filter electric current I, and whether the electric current I that judges to accept filter is greater than current setting value I _setif be greater than, then output logic signal 1, otherwise, output logic signal 0;

Voltage low-pass filter unit process ac voltage measurement value V _meas, and output filtering voltage V, adopt following formula to calculate described filtering voltage V:

$\frac{V\left(s\right)}{V_{meas}\left(s\right)}=\frac{1}{1+T_{V}s},---\left(2\right)$

Wherein, T _vfor voltage integrating meter constant, s is laplace operator;

Voltage comparator accepts filter voltage V, and by itself and voltage setting value V _setcompare, if filtering voltage is greater than voltage setting value, then output logic signal 1, otherwise output logic signal 0;

The logical signal that logical AND gate receiver voltage comparator and current comparator export, and carry out "AND" process, export the first logical signal S1 to non-linear modulation unit, described first logical signal S1 value is 0 or 1.

Differentiator carries out differential calculation to the filtering voltage V that voltage low-pass filter unit exports, and obtains filtering voltage differential value;

Pulse generate unit receives and judges whether filtering voltage differential value is greater than pulse settings value D; If be greater than, then the second logical signal S2=1 exported, the duration is setting value T; Otherwise, export the second logical signal S2=0 all the time;

The second logical signal S2 that binary channels selector received pulse generation unit exports, and export extinguish angle deviation increment signal Δ γ _err.If the second logical signal S2=0, then extinguish angle deviation increment signal Δ γ _err=0; If the second logical signal S2=1, then extinguish angle deviation increment signal Δ γ _err=X2, wherein, X2 is the value of setting; The extinguish angle deviation increment signal Δ γ exported _errthe the second extinguish angle deviation signal γ exported with non-linear modulation unit _err2be added, obtain the 3rd extinguish angle deviation signal γ _err3, and the 3rd extinguish angle deviation signal γ _err3export pi element to.

As preferably, described non-linear modulation unit, its second extinguish angle deviation γ exported _err2the first extinguish angle deviation γ of input _errpiecewise linear function, Function feature is have the broken line be made up of seven key points;

Described seven key points are N ', N, M, O, A, B and B ', by different modes straight line each point coupled together and namely form required function.Described seven key points have following characteristics:

O is the origin of coordinates; First key point N ' point meets: X _{n '}<X _mand Y _{n '}=-90; Second key point N meets: X _n<X _{n '}and Y _{n '}=-90; 3rd key point M meets: X _m=Y _m<0; 5th key point A meets: X _a=Y _a>0; 6th key point B point meets: X _b>X _aand Y _b=90; 7th key point B ' point meets: X _{b '}>X _band Y _{b '}=90.Wherein: X _{n '}and Y _{n '}be respectively abscissa and the ordinate of the first key point; X _nand Y _nbe respectively abscissa and the ordinate of the second key point; X _mand Y _mbe respectively abscissa and the ordinate of the 3rd key point; X _aand Y _abe respectively abscissa and the ordinate of the 5th key point; X _band Y _bbe respectively abscissa and the ordinate of the 6th key point; X _{b '}and Y _{b '}be respectively abscissa and the ordinate of the 7th key point.

As the S1=0 that logical AND gate unit exports, piecewise function is by a broken line that N-M-O-A-B '-B connects to form successively; As S1=1, piecewise function is by a broken line that N-N '-M-O-A-B '-B connects to form successively.

Describedly get the extinguish angle sampled value that junior unit receives certain moment, and this sampled value is formed one together with other all sampled values in 20ms before this moment gather, export the minimum value in this set.

The purpose of this utility model also can be achieved through the following technical solutions: a kind of gamma kick circuit improving Commutation Failures In Hvdc Transmission Systems restorability, comprising:

1) get junior unit, for receiving, storing and compare extinguish angle sampled value, and get minimum value and export.By the γ preset _refdeduct the output valve of this unit, obtain extinguish angle error amount γ _err.

2) non-linear modulation unit, in order to the γ to input _errmodulate; Output S1 according to logical AND gate AND determines concrete modulation system; Export γ _err2, and with the output Δ γ of binary channels selector _errbe added, as the input of pi element.

3) pi element, in order to according to input γ _err3solve and export controlled quentity controlled variable β _γ, computing formula is as follows:

$\frac{b_g\left(s\right)}{g_{err3}\left(s\right)}=K+\frac{1}{T_{i}s}---\left(1\right)$

Wherein, s is pull-type operator, and K is proportionality constant, T _ifor integral constant.Constant π deducts and exports β _γform trigger angle control amount α.

4) pulse-triggered unit, receives trigger angle control amount α, and controls the break-make of thyristor in DC converter accordingly.

5) low-pass filter unit, in order to process DC current measures I _dmeaswith ac voltage measurement value V _meas, export I and V, adopt following formula to carry out filtering calculating:

$\frac{OUT\left(s\right)}{IN\left(s\right)}=\frac{1}{1+T_{x}s}---\left(2\right)$

Wherein, OUT and N represents output and input respectively, T _xfor integral constant, s is laplace operator.

6) comparator, by the I (or V) of input and set point I _set(or V _set) compare, according to comparative result output logic signal 0 or 1.

7) logical AND gate AND, receive 6) in two comparators output and carry out "AND" process, output logic signal S1 is to non-linear modulation unit.

8) differentiator, do differential process to filtered alternating voltage V, differentiation result exports pulse generate unit to.

9) pulse generate unit, compares 8) export numerical value whether be greater than set point D; If be greater than, then export S2=1, and the T that holds time, otherwise S2=0.

10) binary channels selector, selects to export numerical value X1 and X2 according to the output S2 of pulse generate unit; If S2=0, then export Δ γ _err=X1, otherwise Δ γ _err=X2.

Describedly get junior unit, receive the extinguish angle sampled value in certain moment, and this sampled value is formed one together with other all sampled values in 20ms before this moment gather, export the minimum value in this set.

Described component nonlinearities modulating unit, its output variable γ _err2input variable γ _errdispositif de traitement lineaire adapte function, assuming that input variable is transverse axis X, output variable is longitudinal axis Y, and described dispositif de traitement lineaire adapte function has following two kinds of features:

The first: ' seven key point that function has N ', N, M, O, A, B, B, to be coupled together each point by different modes straight line and namely forms required function.The feature of seven points comprises: O is the origin of coordinates; A point meets: X _a=Y _a>0; B point meets: X _b>X _aand Y _b=90; B ' point meets: X _{b '}>X _band Y _{b '}=90; M point meets: X _m=Y _m<0; N ' point meets: X _{n '}<X _mand Y _{n '}=-90; N point meets: X _n<X _{n '}and Y _{n '}=-90.

The second: as the S1=0 that logical AND gate unit exports, piecewise function is by a broken line that N-M-O-A-B '-B connects to form successively; As S1=0, piecewise function is by a broken line that N-N '-M-O-A-B '-B connects to form successively.

Principle of the present utility model: the utility model has nonlinear closed-loop control and feedfoward control, comprises and gets junior unit, non-linear modulation unit, pi element, pulse-triggered unit, low-pass filtering, comparator, logical AND gate, differentiator, pulse generate unit and binary channels selector; Wherein the first seven element is subordinate to close loop control circuit, and low pass filtered involves rear three elements and is under the jurisdiction of feed forward control loop.

Relative to prior art, the utility model has following advantage and beneficial effect: clear physics conception of the present utility model, and circuit structure is succinct, and only need increase subelement newly in traditional gamma kick circuit can realize; After adopting the utility model to transform original gamma kick circuit, effectively can overcome the follow-up commutation failure that AC fault removes rear inverter, accelerate the recovery of direct current active power, and the inverter accelerating to occur commutation failure to a certain extent recovers commutation.Compared to traditional extinguish angle linear scale integral control, the commutation failure of converter after this control circuit can effectively avoid AC fault to remove, and accelerate the recovery of direct current active power to a certain extent, suppress the consumption of direct current reactive power.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of new gamma kick circuit.

Fig. 2 is the nonlinear function schematic diagram of non-linear modulation unit.

Fig. 3 adopts the direct current before and after the utility model to recover the contrast of response simulation result.

Specific embodiment

Below in conjunction with embodiment and accompanying drawing, the utility model is described in further detail, but execution mode of the present utility model is not limited thereto.

Embodiment

As shown in Figure 1, described utility model Sample AC voltage measuring value V respectively _meas, DC current measures I _dmeaswith extinguish angle measured value γ _meas.

Ac voltage measurement value delivers to the input of voltage low-pass filter unit, and the filtering voltage signal V that voltage low-pass filter unit output exports delivers to the input of differentiator and the input of voltage comparator respectively simultaneously.1. differentiator perform and differentiate after acquired results be delivered to the input of pulse generate unit.Whether pulse generate unit judges input data are greater than set point D, if be greater than, then pulse generate unit exports the second logical signal S2=1, and the duration of this signal is T, and wherein T is a setting value; Otherwise, export the second logical signal S2=0 all the time.Second logical signal is delivered to the input of binary channels selector, and binary channels selector is determined to export extinguish angle deviation increment signal Δ γ according to the value of the second logical signal S2 _errvalue: if S2=1, then binary channels selector exports Δ γ _err=X2, wherein X2 is the value of setting; If S2=0, then binary channels selector exports Δ γ _err=0.2., after filtering voltage signal V delivers to the input of voltage comparator, judge whether filtering voltage signal is greater than voltage setting value V by voltage comparator _setif be greater than, then the first input end of output logic signal 1 to logical AND gate (representing with AND in FIG), otherwise the first input end of output logic signal 0 to logical AND gate.

DC current measures delivers to the input of electric current low-pass filter unit, and the filtered current signal I that electric current low-pass filter unit output exports delivers to the input of current comparator, judges whether filtered current signal is greater than current setting value I by current comparator _setif be greater than, then second input of output logic signal 1 to logical AND gate AND, otherwise the second input of output logic signal 0 to logical AND gate.Logical AND gate accepts the logical signal of two inputs and carries out logic "and" operation, and gained operation result is the first logical signal S1.Extinguish angle measured value is delivered to the input getting junior unit, gets junior unit and is compared by all sampling extinguish angle measured values of 20ms before the extinguish angle measured value of sampling and sampling instant, ask for and export minimum value wherein.By the extinguish angle extinguish angle setting value γ preset _refdeduct the output of getting junior unit, obtain the first extinguish angle deviation signal γ _err, and the first extinguish angle deviation signal γ _errbe delivered to the first input end of non-linear modulation unit.The first logical signal S1 that second input receive logic of non-linear modulation unit and door export, non-linear modulation unit exports the second extinguish angle deviation signal γ _err2, the extinguish angle deviation increment signal Δ γ of the second extinguish angle deviation signal and binary channels selector output end _errbe added, obtain the 3rd extinguish angle deviation signal γ _err3, the 3rd extinguish angle deviation signal is delivered to pi element, pi element output delay angle controlled quentity controlled variable β _γ.The delay angle controlled quentity controlled variable β of pi element output is deducted by constant π _γobtain trigger angle control amount α, trigger angle control amount is delivered to pulse-triggered unit.

As shown in Figure 2, the second extinguish angle deviation γ of non-linear modulation unit output _err2the first extinguish angle deviation γ of input _errpiecewise linear function, Function feature is have the broken line be made up of seven key points.

Described seven key points are N ', N, M, O, A, B and B ', the feature of seven points comprises:

O is the origin of coordinates; First key point N ' point meets: X _{n '}<X _mand Y _{n '}=-90; Second key point N meets: X _n<X _{n '}and Y _{n '}=-90; 3rd key point M meets: X _m=Y _m<0; 5th key point A meets: X _a=Y _a>0; 6th key point B point meets: X _b>X _aand Y _b=90; 7th key point B ' point meets: X _{b '}>X _band Y _{b '}=90.Wherein: X _{n '}and Y _{n '}be respectively abscissa and the ordinate of the first key point; X _nand Y _nbe respectively abscissa and the ordinate of the second key point; X _mand Y _mbe respectively abscissa and the ordinate of the 3rd key point; X _aand Y _abe respectively abscissa and the ordinate of the 5th key point; X _band Y _bbe respectively abscissa and the ordinate of the 6th key point; X _{b '}and Y _{b '}be respectively abscissa and the ordinate of the 7th key point.

If the first logical signal S1=0 that logical AND gate unit exports, piecewise function is by a broken line that N-M-O-A-B '-B connects to form successively; If during S1=1, piecewise function is by a broken line that N-N '-M-O-A-B '-B connects to form successively.The each constant numerical value related in the present embodiment is as shown in following table table 1:

Table 1

As shown in Figure 3, present embodiment is adopted to carry out gamma kick to direct current system, inverter side change of current bus arranges three phase short circuit fault, earth resistance is 20 Ω, duration is 100ms, response difference between the proportional plus integral control that simulation comparison is traditional and the utility model, the electric parameters such as idle that diagram variable is followed successively by Inverter Station alternating voltage, extinguish angle, direct current are gained merit, current conversion station absorbs from AC system.As seen from the figure, after adopting utility model to transform former control system, after commutation failure, converter recovers commutation sooner first, and no longer occurs follow-up commutation failure after AC fault is removed; Later convalescent extinguish angle falls after rise faster, accelerates the recovery of active power and reduces current conversion station dynamic reactive demand.

Above-described embodiment is the utility model preferably execution mode; but execution mode of the present utility model is not restricted to the described embodiments; change, the modification done under other any does not deviate from Spirit Essence of the present utility model and principle, substitute, combine, simplify; all should be the substitute mode of equivalence, be included within protection range of the present utility model.

Claims (4)

1. improve a gamma kick circuit for DC transmission system commutation failure restorability, it is characterized in that, comprising: the non-linear modulation unit connected successively, pi element and pulse-triggered unit;

Non-linear modulation unit is to the first extinguish angle deviation signal γ of input _errmodulate, and export the second extinguish angle deviation signal γ _err2;

Pi element receives the second extinguish angle deviation signal γ _err2, the input variable of self is labeled as the 3rd extinguish angle deviation signal γ _err3, and computing relay angle controlled quentity controlled variable β _γ, described delay angle controlled quentity controlled variable β _γcomputing formula as follows:

Wherein, s is pull-type operator, and K is proportionality constant, T _ifor integral constant, constant π deducts delay angle controlled quentity controlled variable β _γobtain trigger angle control amount α;

Pulse-triggered unit receives trigger angle control amount α, and controls the break-make of DC converter thyristor by described trigger angle control amount α.

2. improve the gamma kick circuit of DC transmission system commutation failure restorability according to claim 1, it is characterized in that, also comprise: get junior unit, electric current low-pass filter unit, current comparator, voltage low-pass filter unit, voltage comparator and logical AND gate; Get an input of the output connected nonlinearity modulating unit of junior unit, electric current low-pass filter unit, current comparator are connected successively with an input of logical AND gate, and voltage low-pass filter unit, voltage comparator are connected successively with another input of logical AND gate; The output of logical AND gate is connected with another input of non-linear modulation unit;

Get junior unit to receive, store and compare the extinguish angle measured value g in 20ms _measand obtain the minimum value of extinguish angle sampled value, by extinguish angle setting value γ _refdeduct the minimum value of extinguish angle sampled value, obtain the first extinguish angle deviation signal γ _err, and the first extinguish angle deviation signal γ _errbe delivered to non-linear modulation unit;

Electric current low-pass filter unit process DC current measures I _dmeas, and output filtering electric current I, adopt following formula to calculate described filtered circuit I:

Wherein, T _ifor current integration constant, s is laplace operator;

Current comparator accepts filter electric current I, and whether the electric current I that judges to accept filter is greater than current setting value I _setif be greater than, then output logic signal 1, otherwise, output logic signal 0;

Voltage low-pass filter unit process ac voltage measurement value V _meas, and output filtering voltage V, adopt following formula to calculate described filtering voltage V:

Wherein, T _vfor voltage integrating meter constant, s is laplace operator;

Voltage comparator accepts filter voltage V, and by itself and voltage setting value V _setcompare, if filtering voltage is greater than voltage setting value, then output logic signal 1, otherwise output logic signal 0;

The logical signal that logical AND gate receiver voltage comparator and current comparator export, and carry out "AND" process, export the first logical signal S1 to non-linear modulation unit, described first logical signal S1 value is 0 or 1.

3. improve the gamma kick circuit of DC transmission system commutation failure restorability according to claim 1, it is characterized in that, also comprise: the differentiator connected successively, pulse generate unit and binary channels selector;

Differentiator carries out differential calculation to the filtering voltage V that voltage low-pass filter unit exports, and obtains filtering voltage differential value;

Pulse generate unit receives and judges whether filtering voltage differential value is greater than pulse settings value D; If be greater than, then the second logical signal S2=1 exported, the duration is setting value T; Otherwise, export the second logical signal S2=0 all the time;

The second logical signal S2 that binary channels selector received pulse generation unit exports, and export extinguish angle deviation increment signal Δ γ _err; If the second logical signal S2=0, then extinguish angle deviation increment signal Δ γ _err=0; If the second logical signal S2=1, then extinguish angle deviation increment signal Δ γ _err=X2, wherein, X2 is the value of setting; The extinguish angle deviation increment signal Δ γ exported _errthe the second extinguish angle deviation signal γ exported with non-linear modulation unit _err2be added, obtain the 3rd extinguish angle deviation signal γ _err3, and the 3rd extinguish angle deviation signal γ _err3export pi element to.

4. improve the gamma kick circuit of DC transmission system commutation failure restorability according to claim 1, it is characterized in that, described non-linear modulation unit, its second extinguish angle deviation γ exported _err2the first extinguish angle deviation γ of input _errpiecewise linear function, Function feature is have the broken line be made up of seven key points;

Described seven key points are N ', N, M, O, A, B and B ', the feature of seven points comprises:

O is the origin of coordinates; First key point N ' point meets: X _{n '}<X _mand Y _{n '}=-90; Second key point N meets: X _n<X _{n '}and Y _{n '}=-90; 3rd key point M meets: X _m=Y _m<0; 5th key point A meets: X _a=Y _a>0; 6th key point B point meets: X _b>X _aand Y _b=90; 7th key point B ' point meets: X _{b '}>X _band Y _{b '}=90; Wherein: X _{n '}and Y _{n '}be respectively abscissa and the ordinate of the first key point; X _nand Y _nbe respectively abscissa and the ordinate of the second key point; X _mand Y _mbe respectively abscissa and the ordinate of the 3rd key point; X _aand Y _abe respectively abscissa and the ordinate of the 5th key point; X _band Y _bbe respectively abscissa and the ordinate of the 6th key point; X _{b '}and Y _{b '}be respectively abscissa and the ordinate of the 7th key point.