CN205881676U - Combined mutual inductor who opens a way is not afraid of to secondary side - Google Patents

Abstract

The utility model discloses a combined mutual inductor who opens a way is not afraid of to secondary side, combined mutual inductor is at least including a voltage transformer and a current transformer, voltage transformer connects between the generating line, current transformer is not afraid of the current transformer who opens a way for the secondary side, generating line current transformer and conversion current transformer that the current transformer who opens a way includes the punching are not afraid of to the secondary side, the bus current mutual -inductor is used for responding to bus current, output electric connection to the primary wiring end of changing current transformer of bus current mutual -inductor, conversion current transformer, generating line current transformer and voltage transformer realize mechanical connection and electric isolation through the resin of casting among them. The utility model discloses the harm that the secondary side opened a way and cause can fundamentally prevents and stops effectively to, two metering mutual inductor's combination more brings the intensity high, simple to operate's benefit.

Description

Secondary side is not afraid of the combination transformer of open circuit

Technical field

This utility model relates to a kind of secondary side and is not afraid of the combination transformer of open circuit.

Background technology

Novel device, before coming into operation, is required for testing equipment, in order to verify the performance of equipment, Especially security performance and the service behaviour of equipment to be guaranteed.In order to ensure power system security economical operation, it is necessary to right The ruuning situation of power equipment carries out monitoring and measuring.But general measurement and protection device cannot directly access a sub-high pressure and set Standby, and need to become the big electric current scaling transformation of primary system small area analysis, supply measuring instruments and protection device use.

In each link of power system, including generating, power transformation, transmission of electricity, distribution and electricity consumption, it is required for circuit is surveyed Measure, protect and control (hereinafter referred to as observing and controlling).But size of current great disparity in circuit, have to several Wan An from several peaces, these electricity Stream needs to be converted to the electric current that comparison is unified, and additionally the voltage on circuit is the highest, if direct observing and controlling is abnormally dangerous 's.The effect of current transformer (Current transformer is called for short CT) is primary current bigger for numerical value can be passed through Certain no-load voltage ratio is converted to the secondary current that numerical value is less, is used for carrying out protecting, the purposes such as measurement.If no-load voltage ratio is the electricity of 400/5 Current transformer, can be changed into the electric current that reality is 400A the electric current of 5A.In addition to the effect playing current transformation, also act as electricity Gas buffer action.

Current transformer is made up of the iron core closed and winding.Its umber of turn is little, in reality often only Having a circle, namely punching and mistake, go here and there in needing the circuit of electric current measured, therefore it often has whole electric current streams of circuit Crossing, secondary side turn ratio is more, is serially connected in the equipment such as measuring instruments and protective loop.

Current transformer is when normally working, and its secondary circuit is Guan Bi all the time, because it is secondary to be connected on current transformer The impedance of the instrument coil on coil is the least, is equivalent to run under secondary coil short-circuit condition.Transformer secondary coil terminal powers on Pressure only several volts.Thus the magnetic flux in iron core is the least.Although primary coil magnetomotive force can reach hundreds of peace or thousands of ampere-turn Or it is bigger.Operating secondary loop of mutual inductor does not allow open circuit.Otherwise can produce high voltage at the two ends of open circuit to jeopardize Person equipment safety, or make current transformer generate heat.

Time properly functioning, owing to the impedance of Secondary Winding is the least, produced by primary current, magnetomotive force major part is by secondary The magnetomotive force that electric current produces is compensated, and total magnetic flux density is little, the electromotive force of Secondary Winding sensing also not quite, typically not over Tens volts.When secondary circuit is opened a way, impedance infinitely increases, secondary current vanishing, the also vanishing of Secondary Winding magnetomotive force, and Once winding current does not diminishes with second open circuit, loses the magnetomotive compensating action of Secondary Winding, and a magnetomotive force is very Greatly, being completely used for excitation, resultant flux increases suddenly a lot of times, and the magnetic circuit height making iron core is saturated, now primary current All becoming exciting current, produce the highest electromotive force in Secondary Winding, its peak value is up to several kilovolts of volts the most up to ten thousand, prestige Coerce personal safety or cause instrument, protection device, transformer secondary insulating to damage.

Further, since the height of magnetic circuit is saturated, making magnetic induction suddenly increase, in iron core, magnetic hysteresis and eddy-current loss are drastically Rise, can cause that iron core is overheated even burns current transformer.So in Yun Hanging when needs maintenance, verification secondary meter, must First by secondary winding in current transformer or loop short circuit, then must carry out disassembling section, secondary loop of mutual inductor can not be installed Fuse.Solve the existing protective measure of Current Transformer Secondary side output loop open circuit, substantially have following several:

The first, use the pressure cell such as varistor, gas-discharge tube, when Current Transformer Secondary side, output loop is opened Lu Shi, once open-circuit voltage reaches the operation voltage of pressure-sensitive device, and pressure-sensitive device turns on, and makes output voltage control at pressure-sensitive electricity Pressure.But, the conducting voltage of pressure-sensitive device high (more than tens volts), lasting conveyance capacity are little, and the electric current used on circuit is mutual Sensor, the pressure-sensitive device that its specified output is substantially under 5A, prior art is only possible in the range of millisecond (ms) level continue Crossing the electric current that stream is the biggest, and current transformer output loop is once opened a way, the persistent period is unlikely to be ms level.Therefore, pressure Sensing device is protected, it is easy to punctures and forms permanent conducting, it is necessary to changes device and could recover transformer output loop Normal work, or directly burn and do not have protective effect.

The second, when utilizing Current Transformer Secondary side output loop open circuit, once open-circuit voltage reaches certain value, by one The individual coil being attempted by two outfans attracts spring tripping mechanism, and tripping mechanism action makes contact short, thus reaches protection and make With.Owing to coil is attempted by two outfans of transformer, when transformer normally works, coil itself inevitably to flow through one The electric current of partial mutual inductance device secondary side, this portion of electrical current does not flow through the detection equipment that should need to flow through, thus sets to detection For bringing obvious error；Its two, mechanical mechanism is slow in one's movements, and during transformer output open circuit, and voltage rises quickly (us level), Do not play a protective role, and outside accident occurs already.

The third, outfan install a relay, the contact of relay is connected to the two ends of outfan, manipulation fill Put control relay to open and close, realize the protection of output loop of current transformer with this.Need manual intervention completely, for Unexpected open circuit, does not has protective effect at all.

Chinese Patent Application No. 201210196247.6, discloses a kind of current transformer over-voltage protection method and device, This utility model relates to a kind of current transformer over-voltage protection method and device, and described method is to gather Current Transformer Secondary side Current signal；The current signal collected is converted to voltage signal contrast with protection value set in advance, it is judged that institute State whether Current Transformer Secondary side is open circuit；When the voltage signal after conversion is more than described protection value set in advance, short Connect described secondary loop of mutual inductor, when the voltage signal after conversion is not more than described protection value set in advance, recover The normal connection status of described current transformer；Described device includes sampling unit, main control unit, pressure limited protection circuit and open circuit Protection act element, the lead-out terminal of described open-circuit-protection action element be connected to described current transformer lead-out terminal it Between.This utility model uses aptitude manner to be controlled, and uses mechanical switch to complete open-circuit-protection, it is to avoid prior art simultaneously The impact that whole circuit is caused by the heating of lower electronic devices and components.

This utility model and above scheme and prior art thereof, be all the second open circuit afterwards for current transformer Make remedial measure, fail to tackle the problem at its root,

Certainly, understanding too based on above analysis, in prior art, there is not secondary side, not to be afraid of the combination of open circuit mutual Sensor, combination transformer is one-body molded, compact conformation, and utilization rate is high, and therefore, a kind of secondary side is not afraid of the combination transformer of open circuit Also a kind of urgent need is become.

Utility model content

The technical problems to be solved in the utility model is: provide a kind of secondary side not to be afraid of the combination transformer of open circuit, not only Ensure that the precision of measurement, and, it is possible to fundamentally it is effectively prevented the various harm that the open circuit of secondary side causes, two The combination of metering transformer, more brings intensity high, benefit easy for installation.

The technical scheme of the technical problems to be solved in the utility model is:

Secondary side is not afraid of the combination transformer of open circuit, and described combination transformer at least includes a voltage transformer and one Current transformer, the output of voltage transformer summation current transformer is connected to metering device；Described voltage transformer is conventional Voltage transformer, is connected between bus；Described current transformer is the current transformer that secondary side is not afraid of open circuit, described secondary Side is not afraid of the current transformer of open circuit and is included busbar current transformer and the switching current transformer of punching；Described bus current Transformer is in order to sense bus current；The outfan of busbar current transformer is electrically connected to the primary line of switching current transformer Circle terminals；The output of described switching current transformer is in order to be connected to metering device, and described switching current transformer is arranged at The side of busbar current transformer, switching current transformer, busbar current transformer and voltage transformer are by casting therebetween Resin realizes being mechanically connected and electrical isolation.

Preferably, described switching current transformer is high precision current transformer.

Preferably, described voltage transformer and secondary side are not afraid of the current transformer of open circuit and are respectively two, for two watts Meter method measures three phase power；Described voltage transformer is conventional voltage transformer, is connected between three-phase bus；Said two Secondary side is not afraid of the current transformer of open circuit and is serially connected with respectively in two buses.

Preferably, described voltage transformer and secondary side are not afraid of the current transformer of open circuit and are respectively three, described voltage Transformer is conventional voltage transformer, is connected between three-phase bus；Described three secondary sides are not afraid of the Current Mutual Inductance of open circuit Device is serially connected with in three buses respectively.

Excellent effect of the present utility model:

Secondary side of the present utility model is not afraid of the combination transformer of open circuit, is provided with to sense bus current bus current mutual Sensor, at the rear side of busbar current transformer and connect the primary coil of a switching current transformer, switching current transformer The resistance of primary coil is less, be equivalent to the output of busbar current transformer regularly and connect one prevent that it from opening a way negative Carry, therefore can guarantee that the output of busbar current transformer does not haves high-tension situation momently, it is possible to from all On be effectively prevented and stop secondary side and open a way the harm that causes, it is to avoid second open circuit causes the problem that product explodes, safety Reliably, it is ensured that person equipment safety.

This utility model is based on making single electric current and the middle transformer of univoltage type, and combination transformer can also include two Voltage

Mutual inductance

Device and two current transformers, based on two watts, method measures three phase power；And described combination transformer can also Including three voltage transformers and three current transformers, measure for three-phase electricity.This utility model both can ensure each phase current Certainty of measurement, can avoid again Current Transformer Secondary open a way cause product to explode problem, safe and reliable, it is ensured that the person sets Standby safety

The combination of the metering transformer of more than two, not only has the excellent of the single combination current transformer not being afraid of open circuit Point, more brings intensity high, benefit easy for installation.

Accompanying drawing explanation

Accompanying drawing described herein is further appreciated by of the present utility model in order to providing, and constitutes this utility model application A part, schematic description and description of the present utility model is used for explaining this utility model, is not intended that this practicality new The improper restriction of type.

With embodiment, this utility model is further illustrated below in conjunction with the accompanying drawings.

Accompanying drawing 1 is the electrical connection schematic diagram of a kind of embodiment of this utility model；

Accompanying drawing 2 is the structural representation of a kind of embodiment of this utility model.

1, the first transformer, the 11, first busbar current transformer, the 12, first switching current transformer,

2, the second transformer, the 21, second busbar current transformer, the 22, second switching current transformer,

3, current bus bar,

4, resin,

51, the first voltage transformer, the 52, second voltage transformer,

6, lifting nut,

7, binding post.

Detailed description of the invention

Below by way of particular specific embodiment, technology contents of the present utility model being described, those skilled in the art can be by The content that this specification discloses understands further advantage of the present utility model and effect easily.This utility model also can pass through other Different specific embodiments is implemented or is applied, the every details in this specification also can based on different viewpoints and application, Various modification and change is being carried out under spirit of the present utility model.

Below in conjunction with accompanying drawing, this utility model is described in further detail.

Furthermore, it is necessary to explanation, unless stated otherwise or point out, otherwise the term in description " first ", " the Two ", the description such as " the 3rd ", " A phase ", " B phase ", " C phase " is used only for each assembly in differentiation description, element, step, only Merely to describe conveniently waits rather than for representing that the logical relation between each assembly, element, step or order are closed Systems etc., are not concrete particularly appointment.

In order to solve from source, the various adverse consequencess that Current Transformer Secondary side open circuit brings, of the present utility model two The combination current transformer of open circuit is not afraid of in secondary side, is made that creative conceptual design.

Secondary side is not afraid of the combination transformer of open circuit, and described combination transformer at least includes a voltage transformer and one Current transformer, the output of voltage transformer summation current transformer is connected to metering device；Described voltage transformer is conventional Voltage transformer, is connected between bus；Described current transformer is the current transformer that secondary side is not afraid of open circuit, described secondary Side is not afraid of the current transformer of open circuit and is included busbar current transformer and the switching current transformer of punching；Described bus current Transformer is in order to sense bus current；The outfan of busbar current transformer is electrically connected to the primary line of switching current transformer Circle terminals；The output of described switching current transformer is in order to be connected to metering device, and described switching current transformer is arranged at The side of busbar current transformer, switching current transformer, busbar current transformer and voltage transformer are by casting therebetween Resin realizes being mechanically connected and electrical isolation.

Preferably, described switching current transformer is high precision current transformer.Conventional, switching current transformer is 5A/5A type.In order to by measuring accuracy, switching current transformer can use the high precision current transformer of routine techniques.Example As the current transformer of 0.1 class precision can be used.

Precision current transformer iron core can use high permeability soft magnetic material roll-forming, high temperature protection heat treatment, and one or two Secondary coil high-strength polyester enamel-covered wire, and with absorbance very low insulation material coiling, coil surface recoat processes, lead end The enough contacts area of conducting rod, it is ensured that stable performance is safe and reliable to operation.It is applicable to research unit, test chamber, factory, electric current Transmission of quantity value, precision current measurement, standard mutual inductor.

Preferably, described voltage transformer summation current transformer is respectively two, and based on two watts, method measures three phase power； The output of voltage transformer summation current transformer is connected to metering device, and described voltage transformer is conventional voltage transformer, It is connected between three-phase bus；Said two current transformer is secondary side and is not afraid of the current transformer of open circuit, said two Secondary side is not afraid of the current transformer of open circuit and is serially connected with respectively in two buses.

Preferably, described voltage transformer summation current transformer is respectively two, measures for three-phase electricity, voltage transformer It is conventional voltage transformer that the output of summation current transformer is connected to voltage transformer described in metering device, is connected to three-phase female Between line；Described three current transformers are secondary side and are not afraid of the current transformer of open circuit, and described three secondary sides are not afraid of out The current transformer on road is serially connected with in three buses respectively.

In specifically used, when connecing transformator, the voltage terminal in combined instrument transformer and transformator output-parallel, transformation Device electric current line is through the current transformer in combined instrument transformer.

See Fig. 1.To be described in detail with the combination transformer of two voltage transformers and two current transformers below.

Combination transformer described in Fig. 1 includes the first transformer 1 and the second transformer 2 of two independences and mutually insulated, with And two voltage transformers, i.e. first and second voltage transformer 51,52.

Described first transformer 1 and the second transformer 2 include respectively punching first and second busbar current transformer 11, 21 use with the first and second switching current transformer 12,22 being electrically connected, described first and second busbar current transformer 11,21 To be respectively induced bus current.

In order to prevent the accident of the outfan of first and second busbar current transformer 11,21 from opening a way, first and second bus current The outfan of transformer 11,21 is respectively and electrically connected to the primary coil terminals of first and second switching current transformer 12,22. The output of described first and second switching current transformer 12,22 is in order to be connected to metering device.

The resistance of the primary coil of described first and second switching current transformer 12,22 is less, is attempted by first and second bus The outfan of current transformer 11,21, is equivalent to the outfan to first and second busbar current transformer 11,21 and connects one admittedly Fixed load, and then, the most fundamentally solve what the outfan of first and second busbar current transformer 11,21 was surprisingly opened a way Problem.

In description, each embodiment uses the mode gone forward one by one to describe, and what each embodiment stressed is real with other Executing the difference of example, between each embodiment, identical similar portion sees mutually.

Secondary side is not afraid of the manufacture method of the combination transformer of open circuit, comprises the steps:

1st step: conventional, the punching busbar current transformer of coiling phase strain ratio and voltage transformer；

2nd step: conventional, coiling switching current transformer；

3rd step: the output electric property of busbar current transformer is connected to the primary coil terminals of switching current transformer；

4th step: by the busbar current transformer being electrically connected with and switching current transformer, and voltage transformer interval one Set a distance, is positioned in casting die, conventional, carry out vacuum stirring and the casting of resin, and follow-up dry；

5th step: the demoulding.

Preferably, described combination transformer includes two voltage transformers and two current transformers, two mutual induction of voltage Between device and two busbar current transformers of two current transformers of composition and two switching current transformers, it is spaced a spacing From, it is positioned in casting die.

Preferably, described combination transformer includes three voltage transformers and three current transformers, three mutual induction of voltage Between device and three busbar current transformers of three current transformers of composition and three switching current transformers, it is spaced a spacing From, it is positioned in casting die.

Preferably, described switching current transformer is 5A/5A type.

Preferably, described switching current transformer is arranged at the lower section of busbar current transformer.

Preferably, described voltage transformer and busbar current transformer and the switching current transformer forming current transformer Between spacing distance more than 100 millimeters.Enough spacing, advantageously ensure that the insulation index of current transformer.

Seeing Fig. 2, described combination transformer includes two voltage transformers and two current transformers, below will enter it Row describes in detail.

Conventional, first and second transformer 1,2 of coiling phase strain ratio, i.e. first and second busbar current transformer 11,21 and The first and second switching current transformer 12,22 being electrically connected, and first and second voltage transformer 51,52, first and second electricity Pressure transformer 51,52 and first and second busbar current transformer 11,21 and the first and second switching current mutual inductance being electrically connected All keep at a certain distance away between device 12,22, be positioned in casting die by lifting nut 6, carrying out the true of conventional resin Empty stirring and casting, and the follow-up dry and demoulding.

It is also shown in fig. 2 between various transformer being fixedly connected and mutually insulated by resin 4.

Indicating in accompanying drawing 2, described first and second switching current transformer 12,22 is arranged at first and second bus current mutual inductance The lower section of device 11,21, in order to outlet connects.It is also shown for the punching electricity of first and second busbar current transformer 11,21 in fig. 2 Stream bus 3, and the layout schematic diagram to external wiring terminal 7 of middle transformer.

Although this patent is explained with reference to preferred embodiment and accompanying drawing, but above-mentioned explanation should be regarded as illustrative And non-limiting, change that those skilled in the art is made according to spirit of the present utility model and amendment, this patent all should be belonged to Protection domain.

Claims (4)

1. secondary side is not afraid of the combination transformer of open circuit, it is characterised in that:

Described combination transformer at least includes a voltage transformer and a current transformer, voltage transformer and Current Mutual Inductance The output of device is connected to metering device；

Described voltage transformer is conventional voltage transformer, is connected between bus；

Described current transformer is the current transformer that secondary side is not afraid of open circuit, and described secondary side is not afraid of the current transformer of open circuit Busbar current transformer and switching current transformer including punching；Described busbar current transformer is in order to sense bus electricity Stream；The outfan of busbar current transformer is electrically connected to the primary coil terminals of switching current transformer；Described conversion electricity The output of current transformer is in order to be connected to metering device, and described switching current transformer is arranged at the one of busbar current transformer Side, switching current transformer, busbar current transformer and voltage transformer realize being mechanically connected by the resin cast therebetween and Electrical isolation.

Secondary side the most according to claim 1 is not afraid of the combination transformer of open circuit, it is characterised in that:

Described switching current transformer is high precision current transformer.

Secondary side the most according to claim 1 is not afraid of the combination transformer of open circuit, it is characterised in that:

Described voltage transformer and secondary side are not afraid of the current transformer of open circuit and are respectively two, and based on two watts, method measures three-phase Power；

Described voltage transformer is conventional voltage transformer, is connected between three-phase bus；

Said two secondary side is not afraid of the current transformer of open circuit and is serially connected with respectively in two buses.

Secondary side the most according to claim 1 is not afraid of the combination transformer of open circuit, it is characterised in that:

Described voltage transformer and secondary side are not afraid of the current transformer of open circuit and are respectively three,

Described voltage transformer is conventional voltage transformer, is connected between three-phase bus；

The current transformer that described three secondary sides are not afraid of open circuit is serially connected with in three buses respectively.