CN1072854C - Zero transition procedue triggering two-control-three capacitor switching method and appts. - Google Patents

Abstract

The present invention relates to a zero transition process triggering two-control three-capacitor switching method and a device. In the method, an effective value and reactive power to be compensated are calculated by detecting line voltage u<ab> and u<cd> and line currents i<a> and i<o> to determine capacitor groups for switching and drive a triggering circuit to realize the switching together with a zero transition process detecting circuit or a switching state memory circuit. The device is composed of an electric quantity measuring and calculating circuit, a zero transition process condition detecting circuit, a switching control circuit, a power electronic switch triggering circuit and a capacitor switching main circuit, and the switching of three-phase power capacitors is controlled by a two-phase switch. The present invention has the advantages of no transition process of operation, simple structure, few elements, high response speed and good effect on suppressing the fluctuation of voltage.

Description

Zero transition procedue triggers two-control-three capacitor switching method and device

The invention belongs to the power system reactive power compensation technical field, particularly a kind of zero transition procedue triggers two-phase electronic power switch control three-phase capacitor (abbreviation two-control-three capacitor) operation/cutting method and device.

The capacitor switching device is the capital equipment of power system reactive power compensation.Traditional method is by A.C. contactor or air switch opening-closing capacitor bank, because the cycle of the time ratio power frequency of mechanical contact closure is much bigger, add the dispersiveness of mechanical action time, make the switching control of capacitor group can not realize not having the transient process operation, therefore, occur overcurrent and overvoltage inevitably, it has not only shortened the useful life of capacitor switching device greatly but also has seriously influenced power supply quality, and operation is easy to cause electric equipment to damage continually.In order to solve no transient process switched capacitor problem, people have adopted many methods, these methods are summarized and divided two classes: 1) the employing action switch contacts equipment that has fast, better performances is mixed modern control system, for example fuzzy control of computer, Based Intelligent Control etc.; 2) adopt power electronic device to mix electronic circuit logic control or computer control as switchgear.Method 1) do not solve the operate time and the unmatched problem of electric quantity change time of mechanical contact, about the fastest contactor or about 0.05s of air switch time, and a power frequency period has only 0.02s, add the upper contact head dispersiveness of operate time, in fact the moment of closing operation can not be selected, thereby transient process can not be avoided.Method 2) can select closing operation constantly, but the closing operation condition that existing method is selected is incorrect, have according to power factor or reactive requirement amount as controlled condition, have with supply voltage maximum or zero passage as the combined floodgate condition, the former does not select closing moment, the latter does not satisfy no transient process condition, because the residual voltage on the electric capacity changes, supply voltage also fluctuates, so only electronic power switch switching under the zero transition procedue condition could really avoid operating the transient process that causes.

Purpose of the present invention is exactly that a kind of zero transition procedue of studying at above-mentioned situation triggers two-phase electronic power switch control three-phase capacitor operation/cutting method and device.

The purpose of foregoing invention realizes by following method and apparatus.

Method of the present invention comprises the following steps:

(1) detects two line voltage (u _Ab) and (u _Cb) and two line current (i _a) and (i _c);

(2) calculate the effective value and the reactive power Q to be compensated of voltage and current according to step (1);

(3), determine corresponding switched capacitor group, and send corresponding switching control signal according to the result of calculation of step (2).

(4) (a is b) with another supply voltage (u between (c) mutually to detect electronic power switch place phase _Ab), (u _Cb) and condenser voltage (u _{A ' b '}), (u _{B ' c '});

(5) determine the zero transition procedue trigger condition according to step (4), promptly determine the input moment of capacitor, capacitor zero transition procedue input is constantly: $\mathrm{\&alpha;}=\arcsin [u_c\left(O_{+}\right)\frac{\left|Z\right|}{U_m{X}_c}+{90}^o-\mathrm{\&phi;}-----\left(1\right)$

In the formula: X _cThe capacitive reactance of-capacitor (Ω), $X_c=\frac{1}{\mathrm{\&omega;c}};$

| Z|-condenser impedance (Ω), $\left|Z\right|=\sqrt{R^2+{\mathrm{<figure-callout\; id="2"\; label="X\; c"\; filenames="C9710935400101.png"\; state="\{\{state\}\}">X</figure-callout>}}_c^{}}\&ap;X_c,$

Wherein: R is a condenser resistance;

φ-condenser impedance angle (°), $\mathrm{\&phi;}=\mathrm{arctg}\frac{1}{\mathrm{R\&omega;c}}\&ap;{90}^o;$

The initial phase angle of α-line voltage (°);

U _mThe amplitude of-line voltage (V);

u _c(O ₊Residual voltage on the)-capacitor (V).

(6) the zero transition procedue trigger condition formula (1) according to step (5) produces " zero transition procedue detection " signal;

(7) remember the group and the running status of switched capacitor;

(8) produce corresponding status signal according to step (7);

(9) form capacitor input triggering signal according to step (3) and step (6), trigger corresponding electronic power switch conducting;

(10) form the capacitor triggering signal that works on according to step (3) and step (8), keep working on of electronic power switch;

(11) when excision capacitor group, corresponding switching control signal is put " excision " state, the excision capacitor.

Device of the present invention is by electrical measurement and counting circuit, the zero transition procedue testing circuit, and the switching control circuit, electronic power switch circuits for triggering and capacitor group switching main circuit constitute, wherein:

Electric weight detection and counting circuit are by input circuit 1, and signal processing circuit 2 and electric weight counting circuit 3 constitute, and the input of input circuit 1 passes through voltage transformer pt 1, PT2 summation current transformer CT1, CT2 lead-in voltage u respectively _Ab, u _CbWith line current i _a, i _c, the input of the output termination signal processing circuit 2 of input circuit 1, the output termination voltameter of signal processing circuit 2 is calculated the input of circuit 3;

The switching control circuit is by functional parameter initialization circuit 8; manual automatic function commutation circuit 5; manual switching circuit 4; automatic switching control circuit 6; switching protective circuit 7 constitutes; and the input of automatic switching control circuit 6 connects the output of electric weight counting circuit 3 respectively, and the output of the output of switching protective circuit 7 and functional parameter initialization circuit 8, the output of the output of automatic switching control circuit 6 and manual switching circuit 4 are taken over the input of moving automatic function commutation circuit 5 respectively.

The electronic power switch circuits for triggering by with Men ﹠amp; 1,, ﹠amp; 2, or door H ₁, circuits for triggering 10, switching state memory circuit 11, zero transition procedue testing circuit 12 and synchronous circuit 9 constitute, and with Men ﹠amp; 1 input is taken over the output of moving automatic function switching 5 and zero transition procedue testing circuit 12 respectively, with Men ﹠amp; 2 input is taken over the output of moving automatic function switching 5 and switching state memory circuit 11 respectively, or door H ₁Input connect respectively with the door ﹠amp; 1 and with Men ﹠amp; 2 output, the input of circuits for triggering 10 connect respectively or door H ₁Output, output of circuits for triggering 10 connects switching state memory circuit 11.The input of synchronous circuit 9 is by device circuit breaker Q F ₁Link to each other with the mains side of load air switch QF and to insert a, b, c three phase mains, the input of output connection circuits for triggering 10.

Capacitor group switching main circuit is by capacitor C ₁, C ₂, C ₃With electronic power switch PES _1a, PES _1cConstitute and capacitor C ₁, C ₂And C ₃Be connected into triangle, capacitor C ₁And C ₃Tie point a ', capacitor C ₁And C ₂Tie point b ', capacitor C ₂And C ₃Tie point c ' connect three inputs of zero transition procedue testing circuit 12, electronic power switch PES respectively _1aAnd PES _1cThe control input end draw the output that contacts Power Generation Road 10, power electronics PES respectively _1aAnd PES _1cAnother input and capacitor C ₁And C ₂Tie point b ' respectively by device circuit breaker Q F ₁Link to each other with the mains side of load air switch QF and to insert a, b, c three phase mains, three inputs in addition of zero transition procedue testing circuit 12 also pass through device circuit breaker Q F respectively ₁Link to each other with load air switch QF mains side access a, b, c three phase mains, electronic power switch PES _1aAnd PES _1cOutput respectively with capacitor C ₁With C ₃Tie point a ' and C ₂With C ₃Tie point c ' be connected.

The automatic part of electrical measurement and counting circuit and switching control circuit is made of integrated circuit or single-chip microcomputer.

The electronic power switch circuits for triggering are made up of electronic circuit, are used to produce trigger impulse.This trigger impulse is the warbled broad pulse of 10KHz, and pulsewidth is greater than 3ms.

Capacitor group switching main circuit is by two-phase electronic power switch PES _1aAnd PES _1cConstitute, be used to control the switching of power capacitor, promptly a mutually with c mutually respectively through electronic power switch PES _1a, PES _1cMeet tie point a ', the c ' of capacitor, and device circuit breaker Q F1 load-side b directly connects capacitor C mutually ₁And C ₂Tie point b ' end.

The two-phase electronic power switch control three-phase capacitor switching device that zero transition procedue manufactured according to the present invention triggers has following characteristics:

1. switching is operated no transient process

When capacitor drops into, be chosen in zero transition procedue time trigger electronic power switch, because the time of the conducting of electronic power switch is very fast, so can be similar to electronic power switch conducting when the zero transition procedue condition satisfies basically, so just overcurrent and overvoltage can not appear.

Adopt different switching control methods, observe condenser voltage by multitrace oscilloscope, electric current on the electrical network and voltage waveform can obtain different results.Adopt switch with mechanical contact switching or the non-zero transition procedue condition of electronic power switch switching to trigger control, switching all overvoltage and overcurrent can occur repeatedly.And adopting electronic power switch that the control of zero transition procedue condition triggers switching repeatedly, overvoltage and overcurrent then do not appear.

When capacitor excised, the electronic power switch trigger impulse was zero (close or block), the main circuit current afterflow, and electronic power switch ends behind current zero-crossing point, and at this moment the road phenomenon does not appear changing in circuit, does not therefore have transient process.

2. major loop structure is simple, element is few

Owing to adopt the mode of two-phase electronic power switch control three-phase capacitor, therefore can reduce by 1/3 electronic power switch element, control triggering electric circuit is also simpler in addition, and the volume of device reduces, and cost descends.

3. response speed is fast, the inhibition voltage fluctuation is effective

Because adopting AC sampling and 80C198 Single Chip Microcomputer (SCM) system calculates at the preceding half cycle of sine wave, second half is controlled, the response speed that can make the capacitor switching device is less than 20ms, add that employing " 8421 " coding connects the capacitor group, can be only with 15 groups of three-phase power capacitors of four groups of electronic power switch switchings, therefore, it is fast to obtain reactive power compensation speed, highly sensitive, the big ups and downs of voltage are had better inhibition effect.

Fig. 1 is an operation principle block diagram of the present invention.

Below in conjunction with accompanying drawing Fig. 1 operation principle of the present invention is further introduced.

The input of input circuit 1 passes through voltage transformer pt 1, PT2 summation current transformer CT1, CT2 lead-in voltage u respectively _Ab, u _CbWith line current i _a, i _cSample, then signal is sent into signal processing circuit 2 and carried out signal processing, be admitted to electric weight counting circuit 3 through the signal after the signal processing, electric weight counting circuit 3 calculates the effective value and the reactive power Q to be compensated of voltage, electric current, and exports to automatic switching control circuit 6.6 pairs of relevant informations of automatic switching control circuit are handled, determine the capacitor group of corresponding switching, produce the switching control signal and output to manual automatic function commutation circuit 5 so that select operational mode, manually another input catcher of automatic function commutation circuit 5 moves switching circuit 4, when manual automatic function switches to when automatic, the switching control signal respectively with the signal of the signal of zero transition procedue testing circuit 12 outputs, 11 outputs of switching state memory circuit through " with door ” ﹠amp; 1 ， ﹠amp; 2 carry out AND operation outputs to disjunction gate H1, and disjunction gate H1 output drives circuits for triggering 10, and circuits for triggering 10 carry out the signal amplification and electronic power switch PES1a and PES1c are triggered in electromagnetic isolation processing back.Switching state memory circuit 11 memory switching state informations are exported corresponding signal.Zero transition procedue testing circuit 12 input a and b mutually, c and the b supply voltage u between mutually _Ab, u _CbWith condenser voltage u _{A ' b '}, u _{B ' c '}, the zero transition procedue trigger condition is provided, the moment of promptly dropping into the capacitor group is formula (1).When the zero transition procedue condition satisfies, signal of zero transition procedue testing circuit output, if this moment, the switching control circuit was also exported one " input " (" 1 ") signal, so corresponding electronic power switch PES _1a, PES _1cTo be triggered and conducting.Produce status signal by switching state memory circuit 11 after the conducting, when the signal of " input " (" 1 ") of switching control circuit output, electronic power switch PES _1a, PES _1cConstantly obtain trigger impulse and keep its conducting state, if " excision " (" 0 ") signal of switching control circuit output this moment, then corresponding electronic power switch be owing to can not obtain trigger impulse, automatic cut-off when its current over-zero, thereby corresponding capacitor is excised by zero transition procedue.Two inputs in addition of automatic switching control circuit 6 are distinguished switching protective circuits 7 and functional parameter initialization circuit 8.Synchronous circuit 9 provides a signal synchronous with supply voltage for circuits for triggering 10.Switching protective circuit 5 provides one to block the signal that triggers to automatic switching control circuit 6 when system's operation troubles.Functional parameter initialization circuit 8 is used for parameter setting.

Embodiments of the invention a: 0.4kV, 480kvar zero transition procedue dynamic reactive compensation device.

Input circuit 1, signal processing circuit 2, manual automatic function commutation circuit 5, manual switching circuit 4, synchronous circuit 9 and electronic power switch circuits for triggering are made up of electronic circuit.Electric weight counting circuit 3, automatic switching control circuit 6, switching protective circuit 7, functional parameter initialization circuit 8 are made of Single Chip Microcomputer (SCM) system, realize functions such as electric weight calculating, automatic switching control, switching protection by computer software.

The electronic power switch circuits for triggering are made up of electronic circuit, and trigger impulse is the warbled broad pulse of 10KHz, and pulsewidth is greater than 3ms.

Electronic power switch PES _1aAnd PES _1cSelect the thyristor of KP100-KP500 (1600V, 100A-500A) for use; Separate unit power capacitor C ₁, C ₂, C ₃Three compatible amount be 16kVar, 0.4kV, wherein a, c respectively connect mutually two anti-and thyristors, b directly is connected to capacitor b ' phase from power supply b mutually.Adopt four groups of electronic power switches to control 15 group capacitors.

The capacitor group adopts 1248 codings to connect, i.e. 1 three-phase capacitor of first winding, second group of 2 three-phase capacitor in parallel, the 3rd group of 4 three-phase capacitors in parallel, the 4th group of 8 three-phase capacitors in parallel.

Claims (5)

1. a zero transition procedue triggers two-phase electronic power switch control three-phase capacitor operation/cutting method, and its characteristic is that this method comprises the following steps:

(1) detects two line voltage (u _Ab) and (u _Cb) and two line current (i _a) and (i _c);

(2) calculate the effective value and the reactive power Q to be compensated of voltage and current according to step (1);

(3), determine corresponding switched capacitor group, and send corresponding switching control signal according to the result of calculation of step (2).

(4) (a is b) with another supply voltage (u between (c) mutually to detect electronic power switch place phase _Ab), (u _Cb) and condenser voltage (u _{A ' b '}), (u _{B ' c '});

(5) determine the zero transition procedue trigger condition according to step (4), promptly determine the input moment of capacitor, capacitor zero transition procedue input is constantly: $\mathrm{\&alpha;}=\arcsin [u_c\left(O_{+}\right)\frac{\left|Z\right|}{U_m{X}_c}+{90}^o-\mathrm{\&phi;}----\left(1\right)$

In the formula: X _cThe capacitive reactance of-capacitor (Ω), $X_c=\frac{1}{\mathrm{\&omega;c}};$

| Z|-condenser impedance (Ω), $\left|Z\right|=\sqrt{R^2+X_c^2}\&ap;X_c,$

Wherein: R is a condenser resistance;

φ-condenser impedance angle (°), $\mathrm{\&phi;}=\mathrm{arctg}\frac{1}{\mathrm{R\&omega;c}}\&ap;{90}^o;$

The initial phase angle of α-line voltage (°);

U _mThe amplitude of-line voltage (V);

u _c(O ₊Residual voltage on the)-capacitor (V).

(6) the zero transition procedue trigger condition formula (1) according to step (5) produces " zero transition procedue detection " signal;

(7) remember the group and the running status of switched capacitor;

(8) produce corresponding status signal according to step (7);

(9) form capacitor input triggering signal according to step (3) and step (6), trigger corresponding electronic power switch conducting;

(10) form the capacitor triggering signal that works on according to step (3) and step (8), keep working on of electronic power switch;

(11) when excision capacitor group, corresponding switching control signal is put " excision " state, the excision capacitor.

2. a zero transition procedue triggers two-phase electronic power switch control three-phase capacitor switching device, it is characterized in that:

Described capacitor switching device is by electrical measurement and counting circuit, the zero transition procedue testing circuit, the switching control circuit, electronic power switch circuits for triggering and capacitor group switching main circuit constitute, wherein electric weight detection and counting circuit are by input circuit (1), and signal processing circuit (2) and electric weight counting circuit (3) constitute, and the input of input circuit (1) is respectively by voltage transformer (PT1, PT2) summation current transformer (CT1, CT2) lead-in voltage (u _Ab), (u _Cb) and line current (i _a), (i _c), the input of the output termination signal processing circuit (2) of input circuit (1), the output termination voltameter of signal processing circuit (2) is calculated the input of circuit (3);

The switching control circuit is by functional parameter initialization circuit (8); manual automatic function commutation circuit (5); manual switching circuit (4); automatic switching control circuit (6); switching protective circuit (7) constitutes; and the input of automatic switching control circuit (6) connects the output of electric weight counting circuit (3) respectively; the output of the output of switching protective circuit (7) and functional parameter initialization circuit (8), the output of the output of automatic switching control circuit (6) and manual switching circuit (4) are taken over the input of moving automatic function commutation circuit (5) respectively.

The electronic power switch circuits for triggering by with door (﹠amp; 1), (﹠amp; 2), or the door (H1), circuits for triggering (10), switching state memory circuit (11), zero transition procedue testing circuit (12), synchronous circuit 9 constitutes, and with door (﹠amp; 1) input is taken over the output that moving automatic function is switched (5) and zero transition procedue testing circuit (12) respectively, with door (﹠amp; 2) input is taken over the output that moving automatic function is switched (5) and switching state memory circuit (11) respectively, or door (H ₁) input connect respectively and a door (﹠amp; 1) and with door (﹠amp; 2) output, the input of circuits for triggering (10) connect respectively or door (H ₁) output, output of circuits for triggering (10) connects switching state memory circuit (11), the input of synchronous circuit (9) is by device circuit breaker Q F ₁Link to each other with the mains side of load air switch QF and to insert a, b, c three phase mains, the input of output connection circuits for triggering (10)

Capacitor group switching main circuit is by capacitor (C ₁), (C ₂), (C ₃) and electronic power switch (PES _1a), (PES _1c) constitute and capacitor (C ₁), (C ₂) and (C ₃) be connected into triangle, capacitor (C ₁) and (C ₃) tie point (a '), capacitor (C ₁) and (C ₂) tie point (b '), capacitor (C ₂) and (C ₃) tie point (c ') connect three inputs of zero transition procedue testing circuit (12), electronic power switch (PES respectively _1a) and (PES _1c) the control input end draw respectively the contact Power Generation Road (10) output, power electronics (PES _1a) and (PES _1c) another input and capacitor (C ₁) and (C ₂) tie point (b ') respectively by device circuit breaker (QF ₁) link to each other with the mains side of load air switch (QF) and to insert (a) and (b), (c) three phase mains, three inputs in addition of zero transition procedue testing circuit (12) also pass through device circuit breaker (QF respectively ₁) link to each other with load air switch (QF) mains side access (a) and (b), (c) three phase mains, electronic power switch (PES _1a) and (PES _1c) output respectively with capacitor (C ₁) and (C ₃) tie point (a ') and (C ₂) and (C ₃) tie point (c ') be connected.

3. zero transition procedue according to claim 2 triggers two-phase electronic power switch control three-phase capacitor switching device, and it is characterized in that: the automatic part of described electrical measurement and counting circuit and switching control circuit is made of integrated circuit or single-chip microcomputer.

4. trigger two-phase electronic power switch control three-phase capacitor switching device according to claim 2 or 3 described zero transition procedues, it is characterized in that: described electronic power switch circuits for triggering are made up of electronic circuit, are used to produce trigger impulse.This trigger impulse is the warbled broad pulse of 10KHz, and pulsewidth is greater than 3ms.

5. trigger two-phase electronic power switch control three-phase capacitor switching device according to claim 2 or 3 described zero transition procedues, it is characterized in that: described capacitor group switching main circuit is by two-phase electronic power switch (PES _1a) and (PES _1c) constitute, be used for the switching of control capacitor, promptly a mutually with c mutually respectively through electronic power switch (PES _1a), (PES _1c) meet tie point (a '), (c ') of capacitor, and device circuit breaker (QF1) load-side b directly connects capacitor (C mutually ₁) and (C ₂) tie point (b ').

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