CN1212632C

CN1212632C - High-voltage AC combined throw in/off switch

Info

Publication number: CN1212632C
Application number: CN 02112647
Authority: CN
Inventors: 陶骏; 刘正之
Original assignee: Institute of Plasma Physics of CAS
Current assignee: Institute of Plasma Physics of CAS
Priority date: 2002-02-04
Filing date: 2002-02-04
Publication date: 2005-07-27
Anticipated expiration: 2022-02-04
Also published as: CN1437205A

Abstract

The present invention discloses a high-voltage alternating current combined switching switch. A mechanical switch, a varistor and a primary stage of a step-down transformer are connected in parallel, and are connected with a high voltage alternating current loop in series. A secondary stage of the step-down transformer is connected with a solid state switch in parallel. A trigger is formed by primary windings of a synchronous transformer TB bridged on both ends of the high voltage alternating current loop and secondary windings of the synchronous transformer TB electrically connected with a controller KZ, wherein the controller KZ is formed by a trigger pulse retainer MB and a voltage phase trigger XC which are connected in series and are connected with an action delay timer KY of the mechanical switch in parallel. An input terminal for a switching-on signal and a switching-off signal is electrically connected with an upper computer or a manual button. An output terminal of the voltage phase trigger XC is connected with a trigger electrode of the solid state switch. An output terminal of the action delay timer KY of the mechanical switch is connected with an actuating coil of the mechanical switch. The present invention sufficiently reduces the electric stress of the mechanical switch, improves the operating conditions of loads, and obtains high price-to-performance ratio. The present invention can be widely used for the frequent switching of various large high voltage dynamic reactive compensation and filtration devices.

Description

High-voltage AC combined throw in/off switch

Technical field

The present invention relates to adopt the various large-scale dynamic passive compensation and the filter of switch on-off, especially a kind of high-voltage AC combined throw in/off switch that uses in the high-voltage alternating system more than 10KV.

Background technology

Idle and harmonic wave are one of problem demanding prompt solutions in the current electric power system, and to this, multiselect is with various large-scale dynamic passive compensations and filter both at home and abroad, and this wherein has a considerable amount of again is capacitor groups of employing switch on-off.In these equipment, fling-cut switch is very crucial, and its property relationship is to whole device reliability of operation.Generally require fling-cut switch to have service speed and less electric stress faster, be fit to frequent operation, take into account cost simultaneously.The switch that is applied to switching at present mainly contains conventional mechanical switch and thyristor switch.

Conventional mechanical switch generally adopts AC circuit breaker or A.C. contactor, has obtained in the large-scale reactive power compensator of these at home and abroad some using widely, and it is low relatively that it has a cost, the advantage that conducting resistance is little.But simultaneously also exist many weak points: at first, easily restrike during the disjunction capacitor loop, cause overvoltage, during switching manipulation, the spring of contact may occur in addition, this also can produce overvoltage; Secondly, produce very big shoving during combined floodgate; Once more, produce electric arc during separating brake, influence switch life; The 4th, the time delay of switch motion is bigger.As seen, if the operation of the switching of mechanical switch then all has very big harm to compensation condenser and switch itself, so this class switch is not suitable in the fast-changing idle device that compensates too high because of the frequency of its use.

In order to be suitable for frequent operation, to have and adopt thyristor switch.This switch is widely used in low-pressure system, and it has the no electric arc of operation, and the life-span is long, and advantage such as be swift in motion; But in some high-pressure systems more than the 10KV, its application is restricted.Reason is the withstand voltage limited of single thyristor, when it ends, may be filled with voltage on the capacitor, so the thyristor in this class switch should be able to tolerate peak-to-peak voltage in addition.In order to make this switch can be applied in the high-voltage great-current occasion, a kind of direct method is to adopt a plurality of thyristor series and parallels, and this needs the comprehensive dynamic and static measure of all pressing, and also need provide suitable allowance during general simultaneously design.Therefore the cost of the thyristor switch in the high-pressure system is very high, and reliability is relatively poor.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of high-voltage AC combined throw in/off switch for overcoming weak point of the prior art.

The technical scheme that is adopted comprises solid-state switch and the trigger thereof in the loop, particularly mechanical switch, piezo-resistance and step-down transformer elementary is serially connected with in the high-voltage alternating loop after being in parallel and being connected, secondary and the said solid-state switch of said step-down transformer is in parallel and is connected, and said trigger is electrically connected with the trigger electrode of said solid-state switch, the actuation coil of mechanical switch.

Step-down transformer described in the present invention is a variable reactor; Described is that mechanical switch is an A.C. contactor; Described solid-state switch is that anti-thyristor also is right; Described piezo-resistance is a Zinc-oxide piezoresistor; The starting resistor value of described piezo-resistance is the 85-95% of the saturation voltage value of step-down transformer; Described trigger is the elementary cross-over connection of synchrotrans in the two ends in high-voltage alternating loop, secondaryly be electrically connected with controller, said controller is in parallel with mechanical switch action delay device by trigger impulse retainer and voltage-phase trigger serial connection back and connects and composes, its on/off switch signal input part is electrically connected with host computer or hand push button, the meet sb. at the airport actuation coil of tool switch of the trigger electrode of the output termination solid-state switch of voltage-phase trigger, the output of mechanical switch action delay device; The trigger impulse retention time of described trigger impulse retainer is 10 milliseconds when being 100-200 millisecond, separating brake when closing a floodgate, and the delay time of mechanical switch action delay device is 0 millisecond when being 60-100 millisecond, separating brake when closing a floodgate.

To be that present industrial quarters is conventional use for mechanical switch described in the present invention, piezo-resistance and solid-state switch, but they and described step-down transformer have constituted characteristics of the present invention under capacitive load.

Mechanical switch is conventional high-voltage switch gear, generally adopts vacuum switch, and contactor can be paid the utmost attention to because its operation lifetime is long.General vacuum switch because fracture voltage recovers not enough, causes easily and restrikes when cutting electric capacity, and the recovery capability of conventional vacuum switch is enough in the present invention.

To solid-state switch, can adopt common bidirectional thyristor or anti-and thyristor to or anti-and turn-off thyristor right, their withstand voltage (forward and reverse repetitive peak voltage) is greater than 2 times of the voltage peak of the secondary side of step-down transformer, and a general triode thyristor can be competent at.To the selection of its electric current, can consider by short-term operation, according to the I of solid-state switch permission ²T checks.

Can select ZNO or SiC etc. to piezo-resistance, and not have gap ZNO, become first-selection because its discharge capacity is big.Its chargeability is controlled at 70%, guarantees the safe and reliable work of ZNO.

Switching overvoltage and resonance phenomena that effective cooperation of the characteristic of the no-load characteristic of step-down transformer, the characteristic of capacitive load and piezo-resistance can the inhibition system occurs; The appropriate design of the short-circuit parameter of step-down transformer can suppress mechanical switch and close fashionable impact to load.

Beneficial effect with respect to prior art is: one, when the present invention closes a floodgate, trigger is about to the solid-state switch conducting earlier, so that the elementary of step-down transformer presents extremely low impedance, thereby connect the loop, and mechanical switch is closed a floodgate under low-voltage, this helps reducing the electric stress of mechanical switch, because the conducting phase place of solid-state switch is controlled, can realize that no-flashy-flow closes a floodgate, and has further protected switch itself and load simultaneously; Its two, the rapid conducting of solid-state switch makes closing time of the present invention reduce greatly with respect to common mechanical switch, only is 8～10 milliseconds; They are three years old; during separating brake of the present invention; conducting solid-state switch in the disjunction mechanical switch; this maintains very little value with regard to the port voltage that makes mechanical switch; reduction along with the recovery voltage of mechanical switch; avoided restriking, this not only protected mechanical switch but also avoided after capacitor is impacted by overvoltage in the reactive power compensation that connects and the filter possibility.Along with the disappearance of solid-state switch triggering signal, its current over-zero turn-offs, and has realized the sub-switching operation in whole high-voltage alternating loop; Its four, during separating brake of the present invention,, introduced change of current loop along with the conducting of solid-state switch, reduced the arcing time greatly, make mechanical switch disjunction under low current, thereby reduced its electric stress; Its five because in the elementary piezo-resistance that is parallel with of mechanical switch and step-down transformer, this piezo-resistance is limited in the port voltage of transformer in its residual voltage scope, has both avoided ferro resonance, has protected solid-state switch again; Its six because the introducing of step-down transformer, need not the outer bleed-off circuit of plus for the reactive compensation system of frequent switching; Its seven, solid-state switch is connected in the low-pressure end of step-down transformer, has avoided its series connection and complicated protection problem in high-pressure system; Its eight, variable reactor and solid-state switch are just worked in the very short time of closing a floodgate with separating brake, but their overlond runnings, thereby little to its capacity requirement, be beneficial to and reduce cost; Its nine, the ratio of performance to price is higher than all solid state switch far away.

Description of drawings

Below in conjunction with accompanying drawing optimal way of the present invention is described in further detail.

Fig. 1 is that the present invention is used for the circuit theory diagrams when single-phase;

Fig. 2 is the component parts figure of the controller KZ among Fig. 1;

Fig. 3 is the A.C. contactor K among Fig. 1 when closed, anti-and thyristor to the oscillogram of the electric current among the GT to the A.C. contactor K change of current, wherein, CH1 be that instead also thyristor is to the electric current among the GT, CH2 is the electric current of A.C. contactor K;

When Fig. 4 is A.C. contactor K disjunction among Fig. 1, the electric current among the A.C. contactor K to anti-and thyristor to the oscillogram of the GT change of current, wherein, CH1 be that instead also thyristor is to the electric current among the GT, CH2 is the electric current of A.C. contactor K;

Arc voltage and the current waveform figure of A.C. contactor K when Fig. 5 is to use separating brake of the present invention, wherein, CH3 is the arc voltage waveform, CH4 is the current waveform of A.C. contactor K;

Fig. 6 is arc voltage and the A.C. contactor K current waveform figure when using A.C. contactor K disjunction separately, and wherein, CH3 is the arc voltage waveform, and CH4 is the current waveform of A.C. contactor K.

Embodiment

The present invention is a high-voltage AC combined throw in/off switch (single-phase) that is used for the 10KV/1000Kvar filter.Referring to Fig. 1, Fig. 2, in the high-voltage alternating loop that the cross-over connection of the two ends of 10 kilovolts of high-voltage fences has the present invention and filter RLC to be connected into, of the present invention constituting: A.C. contactor K, Zinc-oxide piezoresistor ZnO and variable reactor L elementary is serially connected with before the filter apparatus RLC after being in parallel and being connected, variable reactor L secondary be connected in parallel to anti-and thyristor to GT; Trigger is that the elementary cross-over connection of synchrotrans TB is in the two ends in high-voltage alternating loop, secondaryly be electrically connected with controller KZ, controller KZ wherein is in parallel with mechanical switch action delay device KY by trigger impulse retainer MB and voltage-phase trigger XC serial connection back and connects and composes, the on/off switch signal input part of controller KZ is electrically connected with host computer or hand push button, the retention time was 150 milliseconds when the trigger impulse of trigger impulse retainer MB closed a floodgate, the retention time is 10 milliseconds during separating brake, the anti-thyristor also of the output termination of voltage-phase trigger XC is to the trigger electrode of GT, the delay time of mechanical switch action delay device KY is 70 milliseconds when closing a floodgate, during separating brake be 0 millisecond, the actuation coil of its output termination A.C. contactor K.Its main element parameter is as follows: rated current 180A; The combined floodgate crest voltage 200V of A.C. contactor K, nominal parameter is 10KV/400A; The starting resistor value of Zinc-oxide piezoresistor ZnO is selected 90% of variable reactor L saturation voltage for use; The leakage reactance of variable reactor L is 5%, capacity 50KVA, no-load voltage ratio 6: 1; Anti-thyristor also is to the on-state average current 500A of GT, and withstand voltage 2000V, nominal parameter are 3000V/1000A, and wherein the rated current of thyristor will have bigger allowance according to the difference operation duty ratio of filter RLC.

During combined floodgate, press button or send starting impulse to trigger by host computer, the anti-thyristor also of voltage-phase trigger XC output signal conducting in the trigger is to GT, and short circuit variable reactor L's is secondary, presents minimum impedance its former side, load has been switched on, mechanical switch action delay device KY in the trigger through 70 milliseconds time-delay after, send signal, make A.C. contactor K closure, electric current is shifted to A.C. contactor K GT by anti-thyristor also, and the loop is connected by A.C. contactor K.During separating brake, press button equally or send pulse to trigger by host computer, mechanical switch action delay device KY in the trigger sends signal to the actuation coil that exchanges contactor K, make its separating brake, simultaneously, voltage-phase trigger XC in the trigger provides the triggering signal of anti-thyristor also to GT, make its conducting, realize electric current by A.C. contactor K to anti-and thyristor to the transfer of GT, after 10 milliseconds, because of trigger impulse retention time of trigger impulse retainer MB to voltage-phase trigger XC is closed, thereby anti-thyristor is also disappeared to the triggering signal of GT, anti-and thyristor the electric current of GT also just turn-offed when the zero passage naturally, A.C. contactor K at this moment disjunction has realized separating brake of the present invention.Behind the separating brake,, avoided introducing extra discharge loop like this because the introducing of the high excitatory impedance of variable reactor L makes very fast the discharging to electrical network of energy storage of the capacitor among the filter RLC in the load.

The waveform that electric current when combined floodgate of the present invention and separating brake shifts mutually between anti-thyristor also is to GT and A.C. contactor K sees Fig. 3, Fig. 4 for details.Arc voltage and the current waveform of the present invention A.C. contactor K when separating brake can be referring to Fig. 5.As a comparison, arc voltage and current waveform when Fig. 6 has showed independent use A.C. contactor K branch deenergizing, as seen, this moment, arcing reached 4 milliseconds, and in the present invention, as can be seen, its electric current utmost point promptly decays to zero from the current waveform of A.C. contactor K, and moment has also only appearred in arc voltage.

The present invention also can be used for the three-phase high-voltage AC system, and it only is slightly different on the triggering signal of solid-state switch, but this to be conspicuous conversion to those skilled in the art all drop within protection scope of the present invention.

Claims

1, a kind of high-voltage AC combined throw in/off switch, comprise solid-state switch and trigger thereof in the loop, it is characterized in that: mechanical switch, piezo-resistance and step-down transformer elementary is serially connected with in the high-voltage alternating loop after being in parallel and being connected, secondary and the said solid-state switch of said step-down transformer is in parallel and is connected, and said trigger is electrically connected with the trigger electrode of said solid-state switch, the actuation coil of mechanical switch.

2, switch according to claim 1 is characterized in that mechanical switch is A.C. contactor K.

3, switch according to claim 1 is characterized in that solid-state switch is that anti-thyristor also is to GT.

4, switch according to claim 1 is characterized in that step-down transformer is variable reactor L.

5, switch according to claim 1 is characterized in that piezo-resistance is Zinc-oxide piezoresistor ZnO.

6, switch according to claim 1, the starting resistor value that it is characterized in that piezo-resistance is the 85-95% of the saturation voltage value of step-down transformer.

7, switch according to claim 1, it is characterized in that trigger is the elementary cross-over connection of synchrotrans TB in the two ends in high-voltage alternating loop, secondaryly is electrically connected with controller KZ, said controller KZ is in parallel with mechanical switch action delay device KY by trigger impulse retainer MB and voltage-phase trigger XC serial connection back and connects and composes, its on/off switch signal input part is electrically connected with host computer or hand push button, the meet sb. at the airport actuation coil of tool switch of the trigger electrode of the output termination solid-state switch of voltage-phase trigger XC, the output of mechanical switch action delay device KY.

8, switch according to claim 7, the trigger impulse retention time that it is characterized in that trigger impulse retainer MB when closing a floodgate when 100-200 millisecond, separating brake 10 milliseconds, the delay time of mechanical switch action delay device KY when closing a floodgate when 60-100 millisecond, separating brake 0 millisecond.