CN1222000A - Zero transition procedue triggering two-control-three capacitor switching method and appts. - Google Patents

Abstract

A switching method with two-phase switch control and three-phase power capacitor switching and its device are disclosed. Said method includes measuring line voltage Uab and Ucb and line currents ia and ib, calculating effective value and reactive power to be compensated, determining the capacito groups to be switched, and driving trigger circuit in conjunction with zero transition procedure detection or switching state memory circuit to perform the switching. Said device is composed of such units as electric parameters measuring and calculating, zero transition procedure detection, switching control, electronic switch trigger and capacitor switching circuit. Its advantages are no transition procedure, simple structure, high response speed and high effect on control voltage ripple.

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-control-three capacitor switching 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 but also has influenced power supply quality.Operation is easy to cause device damage continually.In order to solve no transient process capacitor switching problem, people have adopted many methods, these methods are summarized and divided two classes: (1) is adopted and is moved soon, the switch contacts equipment that has of 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) does 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, the transient process that causes in the time of may avoiding operating, 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, and the latter does not satisfy no transient process condition, because the residual voltage on the electric capacity changes.Have only and carry out switching manipulation under the zero transition procedue condition, could really avoid operating the transient process that causes.

Method of the present invention is by detecting two line voltage u _Ab, u _CbWith two line current i _aAnd i _cCalculate voltage and current and effective value and reactive power Q to be compensated, and the capacitor group of determining corresponding switching drives circuits for triggering realizing the switching of capacitor group with zero transition procedue testing circuit output signal or switching state memory circuit output signal, and the input of capacitor is constantly $a=\arcsin \left[u_c\left(O_{+}\right)\frac{\left|Z\right|}{U_a{X}_c}\right]+{90}^o-\mathrm{\ψ}----\left(1\right)$

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

| the impedance of Z|-capacitor (Ω), $\left|Z\right|=\sqrt{R^2+{\mathrm{<figure-callout\; id="2"\; label="X\; c"\; filenames="A9710935400081.png"\; state="\{\{state\}\}">X</figure-callout>}}_c^{}}\&ap;X_c;$

The impedance angle of φ-capacitor (°), $\mathrm{\&psi;}=\mathrm{arctg}\frac{1}{\mathrm{\&omega;CR}}={90}^o;$

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

U _aThe amplitude of-line voltage (V);

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

Device purpose of the present invention is exactly to develop a kind of zero transition procedue two controls three contactless capacitor switching method and devices at above-mentioned situation.

The present invention is by electrical measurement and calculating, and the zero transition procedue condition detects, switching control, and electronic power switch circuits for triggering and capacitor group switching main circuit constitute.Wherein electric weight detects and calculates 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 respectively _1-2Summation current transformer CT _1-2Lead-in voltage u _Ab, u _CbWith line circuit 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; Switching control 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, the output of switching protective circuit 7 and the output of functional parameter initialization circuit 8 respectively, and the output of the output of automatic switching control circuit 6 and manual switching circuit 4 is 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 ₂, circuits for triggering 10, switching state memory circuit 11 and synchro system 9 constitute, and with Men ﹠amp; ₁Input take over respectively moving automatic function switch 5 and zero transition procedue detect 12 output, with Men ﹠amp; ₂Input take over moving automatic function respectively and switch 5 and the output of switching state memory circuit 11, or door H ₁Input connect respectively with the door ﹠amp; ₁With with Men ﹠amp; ₂Output, the input of circuits for triggering 10 connect respectively or the door H ₁Output and the output of synchro system 9, output of circuits for triggering 10 connects switching state memory circuit 11, the input of synchro system 9 draws respectively by line voltage u _Ab, u _BcAnd u _CaCapacitor group switching main circuit is by capacitor group C ₁, C ₂, C ₃, PES _1aAnd PES _1cConstitute and capacitor C ₁, C ₂And C ₃Be connected into triangle, its C ₁And C ₈Tie point a ', C ₁And C ₂Tie point b ', C ₂And C _aTie point C ' connect the input of zero transition procedue testing circuit 12, PES respectively _1aAnd PES _1cInput draw output by circuits for triggering 10, 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 load air switch QF meet a, c to draw, b is three-way.Another input of zero transition procedue testing circuit 12 is also respectively by device circuit breaker Q F ₁Link to each other with load air switch QF meet a, b to draw, c is three-way, PES _1aAnd PES _1cOutput respectively with capacitor C ₁With C ₃Tie point a ' and C ₂With C ₃Tie point C ' be connected.

Below in conjunction with the accompanying drawing illustrated embodiment operation principle of the present invention is further introduced.The automatic part of electrical measurement and calculating and switching control is finished by integrated circuit or Single Chip Microcomputer (SCM) system, by detecting two line voltage u _Ab, u _CbWith two line current i _a, i _cCalculate the effective value of voltage, electric current and reactive power Q to be compensated, and determine the capacitor group of corresponding switching, drive circuits for triggering with zero transition procedue testing circuit output signal or switching state memory circuit output signal; It is the condition that detects zero transition procedue by electronic circuit that the zero transition procedue condition detects, thereby determines the moment that capacitor drops into, and the moment of dropping into the capacitor group is formula (1)

When the zero transition procedue condition satisfies, if switching state memory circuit 11 output signals are " waiting to throw " signal (being one state), so corresponding electronic power switch PES _1a(PES _1c) will be triggered and conducting." input " (i.e. " 1 ") signal of " waiting to throw " signal (i.e. " 1 ") exported by switching state memory circuit 11 after the conducting and switching control output continues to trigger electronic power switch PES together _1a(PES _1c) keep its conducting state; Switching control then is divided into " automatically " and " manually " two parts, and " automatically " finished by electronic circuit or Single Chip Microcomputer (SCM) system, and " manually ", two kinds of operational modes realized the function switching of " automatically " and " manually " by diverter switch by external button manual operation; 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 received the trigger end of power electronic device greater than 3ms after power amplification and pulse transformer isolation; In the capacitor group switching main circuit, the triggering of capacitor group " input " operation depends on that zero transition procedue condition and switching control are output as the situation that " input " (i.e. " 1 ") signal satisfies simultaneously.And keep the capacitor group to be in " input " state, depend on that then it is the situation that satisfy simultaneously " input " (i.e. " 1 ") that switching is controlled the output signal that is output as " input " (i.e. " 1 ") signal and switching state memory circuit 11.When carrying out " cleaning " operation, switching control is output as " cleaning " signal (i.e. " zero " signal), at this moment, and corresponding electronic power switch PES _1a(PES _1c) trigger impulse is zero, the output signal of switching state memory circuit 11 be " excision " signal (promptly " zero " exported), electronic power switch PES accordingly _1a(PES _1c) will be through the natural commutation of electric current and close; Capacitor group switching main circuit adopts two-phase power switch (PES _1aAnd PES _1c) switching of control three-phase power capacitor, as shown in drawings, a mutually with c mutually respectively through electronic power switch PES _1a, PES _1cConnect capacitor group a ', c ' end, and b is directly by the b ＇ end that connects the capacitor group.When satisfying capacitor group " input " condition, electronic power switch PES _1a(PES _1c) triggered and conducting, when satisfied " excision " condition, electronic power switch PES _1a(PES _1c) end when the commutation of electric current nature because of triggerless.

In the present embodiment, electronic power switch PES _1aAnd PES _1cSelect the thyristor of 1600V, 100A for use; Power capacitor C ₁, C ₂, C ₃Capacity be 16kVar, 400V, wherein a, c respectively connect mutually two anti-and thyristors, b directly is connected to capacitor b ' phase from power supply B mutually.The testing circuit of zero transition procedue condition is according to the determined zero transition procedue condition of separating of the capacitance voltage differential equation of capacitor circuit band initial condition, utilizes the gate voltage dead band characteristic of semiconductor diode to be used for detecting the zero transition procedue condition with the composition zero-crossing pulse generator that cooperates of photoelectric coupling triode.

Two-control-three capacitor switching method and device that zero transition procedue manufactured according to the present invention triggers have following features:

1. switching operates no transient process

When capacitor drops into, owing to the moment of its input is depended on the zero transition procedue condition, and the electronic power switch that adopts The time of conducting is very fast, thus basically can be similar to electronic power switch conducting when the zero transition procedue condition satisfies, this Sample just overcurrent and overvoltage can not occur.

Adopt different switching control methods, show that by many tracks crossing device observes condenser voltage, the electric current on the electrical network and voltage wave Shape can obtain different results. Adopt contact switch switching or noncontacting switch in electronic power switch voltage maximum Or triggering control during zero passage, switching all overvoltage and overcurrent can occur repeatedly. And adopt the control of zero transition procedue condition to trigger Noncontacting switch switching repeatedly, overvoltage and overcurrent then do not appear.

When capacitor excised, the electronic power switch trigger impulse was zero (close or block), and the main circuit current afterflow is at electricity Electronic power switch ends after flowing through zero 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 two-phase installing electronic power switch control three-phase capacitor (i.e. two controls, three modes), therefore can reduce 1/3 The electronic power switch element, control triggering electric circuit is also simpler in addition, the volume of device reduces, cost descends.

Fast response time, to suppress voltage pulsation effective

Because adopt AC sampling and 80C198 SCM system to calculate at the front half cycle of sine wave, second half is carried out Control can make the response speed of capacitor switching device less than 20ms, adds that employing " 8421 " coding connects the capacitor group, can Only with 15 groups of three-phase power capacitors of four groups of electronic power switch switchings, therefore, it is fast to obtain reactive-load compensation speed, sensitivity Degree is high, the big ups and downs of voltage is had the effect of better inhibition ability.

Accompanying drawing is an operation principle block diagram of the present invention.

Claims (5)

1. one kind detects the zero transition procedue condition by electronic circuit, thus determine the capacitor input constantly and the zero transition procedue that gives switching trigger two-control-three capacitor switching method, it is characterized in that: by detecting two line voltage u _AbAnd u _CbWith two line current i _aAnd i _cCalculate the effective value of voltage and current and reactive power Q to be compensated, and the capacitor group of definite corresponding switching, drive circuits for triggering to realize the switching of capacitor group with zero transition procedue testing circuit output signal or switching state memory circuit output signal; And the input of described capacitor is constantly: $a=\arcsin \left[u_c\left(O_{+}\right)\frac{\left|Z\right|}{U_a{X}_c}\right]+{90}^o-\mathrm{\&psi;}$

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

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

The impedance angle of φ-capacitor (°), $\mathrm{\&psi;}=\mathrm{arctg}\frac{1}{\mathrm{\&omega;CR}}={90}^o;$

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

U _aThe amplitude of-line voltage (V);

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

2. a zero transition procedue of realizing the described method of claim 1 triggers the two-control-three capacitor switching device, it is characterized in that:

Described capacitor switching device is by electrical measurement and calculating, and the zero transition procedue condition detects, switching control, and electronic power switch circuits for triggering and capacitor group switching main circuit constitute; Wherein:

Electric weight detects and calculates by input circuit ^[1], signal processing circuit ^[2]With the electric weight counting circuit ^[3]Constitute and input circuit ^[1]Input respectively by voltage transformer FT _1～2Summation current transformer CT _1-2Lead-in voltage u _Ab, u _CbWith line current i _a, i _c, input circuit ^[1]Output termination signal processing circuit ^[2]Input, signal processing circuit ^[2]Output termination voltameter calculate circuit ^[3]Input;

Switching control is by the functional parameter initialization circuit ^[8], manual automatic function commutation circuit ^[5], the manual switching circuit ^[4], the automatic switching control circuit ^[6], the switching protective circuit ^[7]Constitute and automatic switching control circuit ^[5]Input connect the electric weight counting circuit respectively ^[3]Output, the switching protective circuit ^[7]Output and functional parameter initialization circuit ^[8]Output, the automatic switching control circuit ^[6]Output and manual switching circuit ^[4]Output take over moving automatic function commutation circuit respectively ^[5]Input.

The electronic power switch circuits for triggering by with Men ﹠amp; ₁, ﹠amp; ₂, or door H ₁, circuits for triggering ^[10], the switching state memory circuit ^[11]And synchro system ^[9]Constitute, and with Men ﹠amp; ₁Input take over moving automatic function respectively and switch ^[5]Detect with zero transition procedue ^[12]Output, with Men ﹠amp; ₂Input take over moving automatic function respectively and switch ^[5]With the switching state memory circuit ^[11]Output, or the door H ₁Input connect respectively with the door ﹠amp; ₁With with Men ﹠amp; ₂Output, circuits for triggering ^[10]Input connect respectively or the door H ₁Output and synchro system ^[9]Output, circuits for triggering ^[10]Output connect the switching state memory circuit ^[11], synchro system ^[9]Input lead wire voltage u respectively _Ab, u _BcAnd u _Ca

Capacitor group switching main circuit is by capacitor group C ₁, C ₂, C ₃, PES _1cAnd PES _2cConstitute and capacitor C ₁, C ₂And C ₃Be connected into triangle, its C ₁And C ₃Tie point a ', C ₁And C ₂Tie point b ', C ₂And C ₃Tie point C ' connect the zero transition procedue testing circuit respectively ^[12]Input, PES _1aAnd PES _1cInput draw the contact Power Generation Road respectively ^[10]Output, PES _1aAnd PES _1cAnother input and capacitor C ₁And C ₂Tie point b ' respectively by device circuit breaker Q F ₁Link to each other with load air switch QF meet a, c to draw, b is three-way, the zero transition procedue testing circuit ^[12]Another input also respectively by device circuit breaker Q F ₁Link to each other with load air switch QF meet a, b to draw, c is three-way, PES _1aAnd PES _1cOutput respectively with capacitor C ₁With C ₃Tie point a ' and C ₂With C ₃Tie point C ' be connected.

3. zero transition procedue two-control-three capacitor switching device according to claim 2 is characterized in that: the automatic part of described electrical measurement and calculating and switching control is finished by integrated circuit or Single Chip Microcomputer (SCM) system, by detecting two line voltage u _Ab, u _CbWith two line current i _a, i _cCalculate the effective value of voltage zero transient process two controls three electric currents and reactive power Q to be compensated, and determine the capacitor group of corresponding switching, drive circuits for triggering with zero transition procedue testing circuit output signal or switching state memory circuit output signal.

4. according to claim 2 or 3 described zero transition procedue two-control-three capacitor switching devices, it is characterized in that: described electronic power switch circuits for triggering are made up of electronic circuit, trigger impulse is the warbled broad pulse of 10kHz, pulsewidth is connected to the trigger end of power electronic device greater than 3ms after power amplification and pulse transformer isolation.

5. according to claim 2 or 3 described zero transition procedue two-control-three capacitor switching devices, it is characterized in that: described capacitor group switching main circuit adopts two-phase electronic power switch PES _1aAnd PES _1cThe switching of control three-phase power capacitor, promptly a mutually with c mutually respectively through electronic power switch PES _1a, PES _1cConnect capacitor group a ', c ' end, and b directly connects the b ' end of capacitor group.

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