CN205910242U - Take transformation ratio conversion current transformer's broad width measurement conversion terminal - Google Patents

Abstract

The utility model discloses a take transformation ratio conversion current transformer's broad width measurement conversion terminal, including at least one current transformer switch unit and controlling means, wherein, little transformation ratio current transformer's input connects to transformation ratio conversion current transformer, it switches and detects current transformer to wear to establish a CT on the circuit of transformation ratio conversion current transformer's an output and big transformation ratio current transformer's input and carried forward, the output that CT switches the measuring current mutual -inductor is connected to controlling means through a signal processing and amplifying unit, another output of transformation ratio conversion current transformer concatenate behind the controllable switch device with big another input of transformation ratio current transformer after the 2nd controllable switch device is exported and connect, form the other end that externally is connected to electric degree metering device, the utility model discloses can the automatic switch -over current transformer of different transformation ratios, the integration degree is high, electric power measuring accuracy is high.

Description

Wide cut with no-load voltage ratio switching current transformer metering switch endpoint

Technical field

This utility model is related to a kind of metering switch endpoint of the wide cut with no-load voltage ratio switching current transformer.

Background technology

Novel device, before coming into operation, is required for equipment is tested, to verify to the performance of equipment, Especially the security performance of equipment and service behaviour will 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 small current, supply measuring instrumentss and protection device to use the high current scaling transformation of primary system.

In each link of power system, including generating, power transformation, transmission of electricity, distribution and electricity consumption, it is required for circuit is surveyed Amount, protection and control (hereinafter referred to as observing and controlling).But size of current great disparity in circuit, have to tens of thousands of Andu from several peace, these electricity Stream needs to be converted to the unified electric current of comparison, and in addition the voltage on circuit is typically all higher, and such as direct observing and controlling is abnormally dangerous 's.The effect of current transformer (current transformer, abbreviation ct) is primary current larger for numerical value can be passed through Certain no-load voltage ratio is converted to the less secondary current of numerical value, for the purposes such as carrying out protecting, measuring.The electricity being 400/5 as no-load voltage ratio Current transformer, can be changed into the actual electric current for 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 closing and winding.Its first winding number of turn is little, in practice often only There is a circle, that is, punching and mistake, in needing the circuit of electric current of measurement, therefore it often has whole electric current streams of circuit to string Cross, secondary side turn ratio is more, be serially connected in the equipment such as measuring instrumentss and protective loop.

In terms of the accuracy of metering: when measuring electric current due to the difference of electrical equipment capacity, need the electricity of measurement Flow valuve varies, if the fixing current transformer larger with one group of no-load voltage ratio is when surveying high current, the current value testing out is smart Degree is higher, but the current value precision that the electrical equipment time-varying regarding low capacity tries out than larger mutual inductor measuring will be relatively low, makes Become error very big.

In current electric-power metering field, often the current transformer of secondary composite transformation ratio is arranged in power circuit, uses Metering when power load is unstable, is measured with little no-load voltage ratio in underload, is measured with large velocity ratio, carried with this during high load capacity High measuring accuracy.But it is in operation, there is problems in that the height of power load, manually can not monitor at any time and switch, if It is high-tension current inductor, very dangerous；Could switch after power failure, lead to switching not in time, do not catch up with the change of load height Change, and manual switching is loaded down with trivial details；Due to switching not in time, when power load hour, current transformer may be transported in large velocity ratio state OK, small current metering misalignment, when circuit power load is high, current transformer is bordering on saturation again, causes Electro-metering not Accurately.

Patent Office of the People's Republic of China discloses a cn201252002y patent, entitled current transformer on June 3rd, 2009 Many gears switched terminal, comprises terminal board, input terminal, lead-out terminal, gear handover module, gauge table holding wire, input Son, lead-out terminal, gear handover module are fixed on terminal board, and input terminal connects the input of gear handover module, output Terminal connects the outfan of gear handover module, and gauge table holding wire connects the signal end of gear handover module.Kept off by changing But position is more complicated to change the no-load voltage ratio structure of current transformer, need more components and parts, relatively costly.

Chinese Patent Application No. 201020615547.x, discloses a kind of Intelligent automatic conversion metering device, belongs to electric power Field of measuring techniques.Including kilowatt-hour meter, composite transformation ratio current transformer, current sampling circuit and switching circuit, switching circuit sets Put the multiple transformation ratio current transformer of connection, current sampling circuit connect composite transformation ratio current transformer it is characterised in that: setting intelligence Processing module and communication module, the input of intelligent processing module connects current sampling circuit, the power end of intelligent processing module Connect power circuit, the communication terminal connecting communication module of intelligent processing module, the outfan of intelligent processing module connects switching electricity Road.Intelligent processing module Treatment Analysis are derived from signal, analysis processing result and the running state data of three-phase current sample circuit Upper level equipment and reading are uploaded by communication module.This utility model does not disclose specific annexation, does not reach and appoints What technology enlightenment.

As can be seen that above scheme and its prior art, it is all that the second open circuit for current transformer is made afterwards Remedial measure, fails to tackle the problem at its root.Equally, the current transformer of different no-load voltage ratios using to measure standard turn Change metering device, in the different current transformer of switching it is impossible to solve second open circuit in handoff procedure to cause high-tension problem, Or for solving the problems, such as that in handoff procedure, second open circuit causes high voltage not ideal enough and practical.

Utility model content

The technical problems to be solved in the utility model is: provides a kind of metering of the wide cut with no-load voltage ratio switching current transformer to turn Change terminal, can intelligently switch the current transformer of different no-load voltage ratios, can effectively prevent the mistake of Current Transformer Secondary side open circuit Voltage, intelligence degree is high, it is possible to increase the accuracy of metering.Using controllable silicon as transfer contact, reliable in action, life-span Long, it is to avoid the fault that electromagnetic relay frequent movement burns out contact and causes.

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

Wide cut with no-load voltage ratio switching current transformer metering switch endpoint, at least provided with having on a phase loop The switching of two bus bar side current transformers of different no-load voltage ratios, described two bus bar side current transformers include one and are used for measuring The little transformation ratio current transformer of smaller current and the current mutual inductor with high transforming ratio of a measurement high current, described band no-load voltage ratio conversion electricity The wide cut metering switch endpoint of current transformer includes at least one current transformer switch unit and control device；Described electric current is mutual Sensor switch unit includes no-load voltage ratio switching current transformer, ct change detection current transformer, the bus for two double no-load voltage ratios Side current transformer switching controllable switch device, wherein, the input of little transformation ratio current transformer is simultaneously connected to no-load voltage ratio conversion electricity Current transformer, an outfan of no-load voltage ratio switching current transformer with an input of current mutual inductor with high transforming ratio and connects, and it is right to be formed Outer connect to one end of watt hour meter making, in an outfan and the current mutual inductor with high transforming ratio of no-load voltage ratio switching current transformer An input and the circuit after connecing on wear a ct change detection current transformer, the output of ct change detection current transformer Connect to control device through a signal processing and amplifying unit, another outfan concatenation first of no-load voltage ratio switching current transformer can After control switching device after another input export through the second controllable switch device with current mutual inductor with high transforming ratio and connect, formed external Connect to the other end of watt hour meter making, described first, second controllable switch device is connected with control device respectively, described control Device processed in order to programme-control can the first, second control conducting of switching device and closing, described control device is connected with power supply.

Preferably, described current transformer switch unit is two, is respectively provided with two for being arranged on quarter-phase circuit The only switching of the bus bar side current transformer of double no-load voltage ratios.

Preferably, described current transformer switch unit is three, is respectively provided with two for being arranged on three-phase loop The only switching of the bus bar side current transformer of double no-load voltage ratios.

Preferably, the input rear portion of described current mutual inductor with high transforming ratio, the front of the second controllable switch device be connected to Prevent the overvoltage inhibiting apparatus of Current Transformer Secondary side open circuit.

Preferably, described first, second controllable switch device is one of controllable silicon, relay contact, described controllable silicon, continues Electrical contact is by control device programme-control.

Preferably, described overvoltage inhibiting apparatus be varistor, tvs pipe, electric capacity, capacitance-resistance series unit, 1:1 electric current change One or a combination set of parallel operation.

Preferably, the output of described control device is also connected with a display and input block, and described display and input block are adopted With liquid crystal display screen or led screen, can achieve touch human computer conversation.

Preferably, the output of described control device is additionally provided with rj45 interface, in order to realize internet function.

Preferably, the output of described control device is also associated with the long-range sending module of gprs for being sent to output signal Specified ip, or on equipment, realize networking, real-time transmission data with user backstage, and can achieve remotely control.

Excellent effect of the present utility model:

1st, the metering of the wide cut with no-load voltage ratio switching current transformer switch endpoint, the electric current of the different no-load voltage ratios that can automatically switch is mutual Sensor, integrated degree is high, and electric-power metering high precision can make 1% point of measuring accuracy reach 0.2%, widen metering fabric width, made Metering is more accurate.

2nd, adopt controllable silicon for electric current transfer contact so as to reliable in action with the current transformer of no-load voltage ratio, convenient, it is to avoid electricity The fault that magnetic relay frequent movement burns out contact and causes.

Brief description

Accompanying drawing described herein further understands to of the present utility model in order to provide, and constitutes this utility model application A part, schematic description and description of the present utility model is used for explaining this utility model, does not constitute new to this practicality The improper restriction of type.

With reference to the accompanying drawings and examples this utility model is further illustrated.

Accompanying drawing 1 is a kind of electrical schematic diagram of embodiment of this utility model,

Accompanying drawing 2 is a kind of actually used principle with a road current transformer switch unit embodiment of this utility model Figure,

Accompanying drawing 3 is a kind of electrical connection principle with two-way current transformer switch unit embodiment of this utility model Figure,

Accompanying drawing 4 is a kind of electrical connection principle with No. three current transformer switch unit embodiments of this utility model Figure.

Specific embodiment

Below by way of particular specific embodiment, technology contents of the present utility model are 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 be by other Different specific embodiments is implemented or is applied, the every details in this specification also can based on different viewpoints and application, Carrying out various modification and change without prejudice 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 3rd ", " a phase ", " b phase ", " c phase " etc. describe each assembly being used only in differentiation description, element, step, only Merely to convenience of description etc., rather than for representing the logical relation between each assembly, element, step or order pass System etc., is not specifically particularly to specify.

Wide cut with no-load voltage ratio switching current transformer metering switch endpoint of the present utility model, at least provided with Yu Yixiang The switching of the two bus bar side current transformers with different no-load voltage ratios on loop, described two bus bar side current transformers include One little transformation ratio current transformer being used for measuring smaller current and the current mutual inductor with high transforming ratio of a measurement high current.

Referring to Fig. 1.

The described metering switch endpoint 9 of the wide cut with no-load voltage ratio switching current transformer includes the switching of at least one current transformer Unit 5 and control device；Described current transformer switch unit 5 includes no-load voltage ratio switching current transformer 6, ct change detection electric current Transformer 4, the bus bar side current transformer switching controllable switch device for two double no-load voltage ratios, wherein, little no-load voltage ratio electric current is mutual The input of sensor is simultaneously connected to no-load voltage ratio switching current transformer 6, and an outfan of no-load voltage ratio switching current transformer 6 is electric with large velocity ratio One input of current transformer simultaneously connects, and forms external connection to one end s1 of the current transformer of watt hour meter making, in no-load voltage ratio One outfan of switching current transformer 6 wears a ct on the circuit with an input of current mutual inductor with high transforming ratio and after connecing and cuts Change detection current transformer 4, the output of ct change detection current transformer 4 connects to control through a signal processing and amplifying unit 3 Device processed, with large velocity ratio Current Mutual Inductance after another outfan concatenation first controllable switch device of no-load voltage ratio switching current transformer 6 After another input of device exports through the second controllable switch device and connect, form external connection to the Current Mutual Inductance of watt hour meter making The other end s2 of device, described first, second controllable switch device is connected with control device respectively, and described control device is in order to program Control can the first, second control conducting of switching device and closing, described control device is connected with power supply.

Preferably, described first, second controllable switch device is one of controllable silicon, relay contact, described controllable silicon, continues Electrical contact is by control device programme-control.

It is exemplified as:

Assume little transformation ratio current transformer range be 100a/5a, current mutual inductor with high transforming ratio range be 200a/5a, and Using 200a/5a as measurement basis, current mutual inductor with high transforming ratio is used for the normality measurement of high current.Little transformation ratio current transformer and , under exporting onesize current conditions, input current size ratio is for 1:2 for current mutual inductor with high transforming ratio.

Practical situation is: if the fixing current transformer larger with one group of no-load voltage ratio is in survey high current, the electricity testing out Flow valuve precision is higher, but when measuring the electrical equipment of low capacity, the current value precision that the larger mutual inductor measuring of no-load voltage ratio tries out is just Can be relatively low, cause error very big.

If passing through control device, accurate measurement during small current is used in using little transformation ratio current transformer, can be abundant Play the best effort scope of the current transformer of little no-load voltage ratio, electric-power metering high precision, 1% point of measuring accuracy can be made to reach 0.2%, widen metering fabric width, made metering more accurate.For example: can be according to payload, by control device programme-control Realize controllable silicon scr1 and scr2 and realize No-contact switch, when may be set in less than 20% load, by little no-load voltage ratio Current Mutual Inductance Metering implemented by device, when load current is higher than 20%, implements metering by current mutual inductor with high transforming ratio.

Have no-load voltage ratio switching current transformer 6 and little transformation ratio current transformer and connect, be equivalent to mutual in little no-load voltage ratio electric current The rear of sensor has simultaneously connect the load of a fixation, excessively electric therefore, it is possible to constantly limit that Current Transformer Secondary side open circuit causes Pressure.And in order to prevent the output open circuit of current mutual inductor with high transforming ratio from causing overvoltage it is preferred that described current mutual inductor with high transforming ratio Input rear portion, the front of the second controllable switch device being connected to prevent the Overvoltage suppressing of Current Transformer Secondary side open circuit Device 7.Conventional, described overvoltage inhibiting apparatus are varistor, tvs pipe, electric capacity, capacitance-resistance series unit, 1:1 current transformation One or a combination set of device.

Tvs (transient voltage suppressor) or title transient voltage suppressor are in stabilivolt technique On the basis of a kind of new product of growing up, its circuit symbol is identical with common Zener diode, profile also with general-purpose diode It is as good as, when the high energy impact events of moment are stood at tvs pipe two ends, it can make it with high speed (up to 1*10-12 second) Impedance reduces suddenly, absorbs a high current simultaneously, by the voltage clamp of its go-and-retum one predetermined numerically, thus really The component protected below damages from the impact of transient state high-energy.The response speed of tvs 10e-12s faster than rc loop, can Without breakdown voltage vbr considering tvs, reverse critical voltage vwm, peak-peak pulse current ipp and maximum clamp voltage vc And peak pulse power pp. selects vwm to be equal to or more than circuit voltage, vc is the pressure voltage less than protection device, can survey Measure best (ipp), or estimate the power of pulse, select the tvs. that power is larger

Tvs pipe has that response time is fast, transient power is big, electric capacity is low, leakage current is low, breakdown voltage deviation is little due to it, Clamp voltage is relatively easy to control, no damage limit, small volume, the advantages of be easily installed, be widely used at present computer system, The every field such as communication apparatus, consumer electronics, power supply, household electrical appliance.

Overvoltage protection device is a kind of advanced protection electrical equipment limiting lightning surge and switching overvoltage.Common mistake Pressure protection components and parts or equipment have lightning protection device, varistor, spark gap etc..In communication power supply field, for preventing thunder and lightning moment high It is caused voltage with huge infringement it will usually configuration varistor carries out over-pressed lightning protection to it.The moment producing when thunder and lightning When high voltage is applied to varistor two ends, varistor resistance becomes infinitely small so that varistor turns on and produces thunder and lightning Raw high current introduces the earth, thus protecting power-supply device not damaged by thunder and lightning.Lightning protection device would generally be used in power-supply system side Overvoltage protection is carried out to alternating current and direct current.

Specifically, in power system, just can effectively be prevented using ctb potline current transformer overvoltage protection device The accident causing because of Current Transformer Secondary open circuit.The abnormal overvoltage that ctb-x protector is mainly used in various ct secondary sides is protected Shield.Protector is connected to Secondary Winding two ends, leaks electricity minimum, in high-impedance state during normal operation.When there is abnormal overvoltage, protect Shield the rapid action of device and short-circuit, panel shows the position of fault, and have passive signal output.After failture evacuation, circuit is extensive After restoring shape, normal operation input work again.

In Fig. 1 embodiment, described first, second controllable switch device is controllable silicon scr1, scr2, and controllable silicon is electric current Transfer contact is so as to reliable in action, convenient, it is to avoid the fault that electromagnetic relay frequent movement burns out contact and causes.

Referring to a kind of actually used principle with a road current transformer switch unit embodiment of Fig. 2 this utility model Figure, a phase loop is provided with two bus bar side current transformers with different no-load voltage ratios, is the first little no-load voltage ratio Current Mutual Inductance respectively Device 1 and the first current mutual inductor with high transforming ratio 2, the input of the first little transformation ratio current transformer 1 to be connected to no-load voltage ratio switching current mutual Sensor 6, an input of an outfan of no-load voltage ratio switching current transformer 6 and the first current mutual inductor with high transforming ratio 2 simultaneously connects, and connect One ct change detection current transformer 4 is worn on circuit afterwards, the output of ct change detection current transformer 4 is through a signal processing Connect to control device with amplifying unit 3, another outfan of no-load voltage ratio switching current transformer 6 concatenates the first controllable switch device After exporting through the second controllable switch device scr2 with another input of the first current mutual inductor with high transforming ratio 2 after scr1 and connect, formed External connection to the current transformer of watt hour meter making other end s2, described first, second controllable switch device scr1, Scr2 is connected with control device respectively, and described control device can first, second control switching device scr1, scr2 in order to programme-control Conducting and closing, described control device is connected with power supply.The input rear portion of described current mutual inductor with high transforming ratio 2, second can The front of control switching device scr2 is simultaneously connected to the overvoltage inhibiting apparatus 7 preventing Current Transformer Secondary side open circuit.

Referring to Fig. 3, it is that a kind of electrical connection with two-way current transformer switch unit embodiment of this utility model is former Reason figure, i.e. current transformer switch unit 51,52, three-phase loop wherein biphase on be provided with two buses of different no-load voltage ratios Side current transformer, the input of first, second little transformation ratio current transformer connects to no-load voltage ratio switching current transformer 61,62, One outfan of no-load voltage ratio switching current transformer 61,62 with an input of first, second current mutual inductor with high transforming ratio and connects, and One ct change detection current transformer 41,42 is worn on the circuit after connecing, and forms external connection to the electricity of watt hour meter making The output of the other end s1, s3 of current transformer, ct change detection current transformer 41,42 is through a signal processing and amplifying unit 31st, 32 connect to control device, and another outfan of no-load voltage ratio switching current transformer 61,62 concatenates the first controllable switch device After scr1, scr3, another input is defeated through second controllable switch device scr2, scr4 with first, second current mutual inductor with high transforming ratio Go out rear and connect, form external connection to the other end s2, s4 of the current transformer of watt hour meter making, described first, second can Control switching device is connected with control device respectively, and described control device first, second can control switching device in order to programme-control Conducting is connected with power supply with closing, described control device.The input rear portion of described first, second current mutual inductor with high transforming ratio, The front of second controllable switch device scr2, scr4 is simultaneously connected to the overvoltage inhibiting apparatus preventing Current Transformer Secondary side open circuit 71、72.

It is that a kind of electrical connection with No. three current transformer switch unit embodiments of this utility model is former referring to accompanying drawing 4 Reason figure.I.e. current transformer switch unit 51,52,53, are respectively arranged with two bus bar side of different no-load voltage ratios on three-phase loop Current transformer, the input of first, second, third little transformation ratio current transformer connect to no-load voltage ratio switching current transformer 61, 62nd, 63, an outfan of no-load voltage ratio switching current transformer 61,62,63 and first, second, third current mutual inductor with high transforming ratio One input simultaneously connects, and wears a ct change detection current transformer 41,42,43 on the circuit after connecing, and forms external connection To the other end s1, s3 of the current transformer of watt hour meter making, the output of s5, ct change detection current transformer 41,42,43 Connect to control device through a signal processing and amplifying unit 31,32,33, no-load voltage ratio switching current transformer 61,62,63 another Big with first, second after outfan concatenation first controllable switch device scr1, scr3, scr5, the 3rd transformation ratio current transformer is another After one input exports through second controllable switch device scr2, scr4, scr6 and connect, form external connection to watt hour meter making Current transformer the other end s2, s4, s6, described first, second controllable switch device is connected with control device respectively, described Control device in order to programme-control can the first, second control conducting of switching device and closing, described control device is connected with power supply. The input rear portion of described first, second, third current mutual inductor with high transforming ratio, second controllable switch device scr2, scr4, the s6 Front is simultaneously connected to the overvoltage inhibiting apparatus 71,72,73 preventing Current Transformer Secondary side open circuit.

In various embodiments above, described overvoltage inhibiting apparatus be varistor, tvs pipe, electric capacity, capacitance-resistance series unit, One or a combination set of 1:1 power pack, and, described first, second controllable switch device be controllable silicon, relay contact it One, described controllable silicon, relay contact are by control device programme-control.

Described control device can process 8 tunnel input signals using built-in central processing unit for core simultaneously, and can root According to needs, its range of application is extended by programming.Control device can design and be programmed to automatically store statistics big Smaller load use Electric situation, and exportable data, convenient inspection and statistics.

Preferably, the output of described control device is also connected with a display and input block, provides straight for the debugging of live near-end The viewing effect seen, and can achieve touch human computer conversation.Described display and input block adopt liquid crystal display screen or led screen, defeated Enter unit and touch human computer conversation can be realized using the touch screen with display and input one.

LCD MODULE is used for real-time display humiture collection result, provides for near-end debugging and intuitively debugs effect； Preferentially, described LCD MODULE only needs to real-time displays temperature and two parameters of humidity, so the liquid crystal display in device Select 16 × 2 lcd1602 with input block.

Lcd1602 is industrial character mode lcd, can show that 16x02 is 32 characters simultaneously.(16 row 2 row) 1602 liquid crystal Also be 1602 character mode lcds, it be a kind of be specifically used to show letter, the dot matrix type Liquid Crystal Module of numeral, symbol etc..It by The dot character such as several 5x7 or 5x11 position forms, and each dot character position can show a character, have between every One point away from interval, also have interval between often going, serve character pitch and the effect of line space, Just because of this thus it Figure (using self-defined cgram, display effect is also bad) can not be shown well.

Lcd1602 Micro Energy Lose, small volume, display content are abundant, ultra-thin light and handy, be commonly used in pocket meter and low-power consumption should With in system.

Preferably, the output of described control device is additionally provided with rj45 interface, in order to realize internet function.Or, described The output of control device is also associated with the long-range sending module of gprs for output signal is sent to specified ip, or on equipment, Realize networking, real-time transmission data with user backstage, and can achieve remotely control.

For example, it is possible to send output signal to the mobile phone formulated by the long-range sending module of gprs, it is easy to related neck Lead timely grasp, to make corresponding decision.The long-range sending module of gprs, has big data internet function, and can be with user Networking, real-time transmission data are realized in backstage, and can achieve remotely control.

In order to data signal is carried out teletransmission, the output of described single-chip microcomputer is also associated with a wireless transmitter module, for inciting somebody to action Alarm signal is sent to specified ip, or on equipment.Preferably, described wireless transmitter module is built with sim900a for core.

Preferably, described wireless transmitter module is applied to China's Mainland sim900a, 900mhz/ from simcom company 1800mhz two-band surface-mount type gprs/gsm module, is interacted with cpu by uart serial ports.Wireless transmitter module wireless transmit mould Block with sim900a as core, by gprs link transmissions humiture result to specify ip address terminal unit or hand-held Equipment.

Sim900a is the wireless module of compact, high reliability, and the double frequency gsm/gprs module using smt encapsulation solves Scheme, using powerful processor arm9216ej-s kernel, can meet low cost, the exploitation of compact size requires.

Using industrial standard interface so that possess the sim900a of gsm/gprs 900/1800mhz function with small size and The high-speed transfer of voice, sms, data and facsimile message is realized in low-power consumption.Sim900a can meet the nearly all application requirement of m2m, Especially compact, compact design.Its physical size is: 24mmx 24mm x 3mm.Based on the technology platform of mature and reliable, And the service support from Product Definition to design and production is provided.

Gateway gprs supporting node is actually gateway or router, it provide gprs and public with X.25 or x.75 agreement interconnection, also supports gprs and the interconnection of other gprs.Ggsn with sgsn is the same all to have ip address, ggsn The routing function of gprs is completed together with sgsn.Gateway gprs supporting node supports x.121 addressing scheme and ip agreement, permissible Ip agreement accesses internet it is also possible to access isdn net.

Professional further appreciates that, in conjunction with the unit of each example of the embodiments described herein description And algorithm steps, can with electronic hardware, computer software or the two be implemented in combination in, in order to clearly demonstrate hardware and The interchangeability of software, generally describes composition and the step of each example in the above description according to function.These Function to be executed with hardware or software mode actually, the application-specific depending on technical scheme and design constraint.Specialty Technical staff can use different methods to each specific application realize described function, but this realization should Think beyond scope of the present utility model.

The step of the method in conjunction with the embodiments described herein description or algorithm can directly be held with hardware, processor The software module of row, or the combination of the two is implementing.Software module can be placed in random access memory (ram), internal memory, read-only deposit Reservoir (rom), electrically programmable rom, electrically erasable rom, depositor, hard disk, moveable magnetic disc, cd-rom or technology In known any other form of storage medium in field.

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 and modification that those skilled in the art is made according to spirit of the present utility model, this patent all should be belonged to Protection domain.

Claims (9)

1. the metering of the wide cut with no-load voltage ratio switching current transformer switch endpoint, at least provided with having not on a phase loop With the switching of two bus bar side current transformers of no-load voltage ratio, described two bus bar side current transformers include one for measurement relatively The little transformation ratio current transformer of small current and the current mutual inductor with high transforming ratio of a measurement high current,

It is characterized in that:

The described metering switch endpoint of the wide cut with no-load voltage ratio switching current transformer includes at least one current transformer switch unit And control device；

Described current transformer switch unit includes no-load voltage ratio switching current transformer, ct change detection current transformer, is used for two The only bus bar side current transformer switching controllable switch device of double no-load voltage ratios

Wherein, the input of little transformation ratio current transformer be connected to no-load voltage ratio switching current transformer, no-load voltage ratio switching current transformer An input of an outfan and current mutual inductor with high transforming ratio and connect, form external connection to one end of watt hour meter making (s1), on the circuit in an outfan of no-load voltage ratio switching current transformer and an input of current mutual inductor with high transforming ratio and after connecing Wear a ct change detection current transformer, the output of ct change detection current transformer connects through a signal processing and amplifying unit It is connected to control device,

Another with current mutual inductor with high transforming ratio after another outfan concatenation first controllable switch device of no-load voltage ratio switching current transformer After one input exports through the second controllable switch device and connect, form external connection to the other end (s2) of watt hour meter making,

Described first, second controllable switch device is connected with control device respectively, and described control device can in order to programme-control First, the conducting of the second control switching device and closing,

Described control device is connected with power supply.

2. a kind of metering switch endpoint of the wide cut with no-load voltage ratio switching current transformer according to claim 1, its feature exists In:

Described current transformer switch unit is two, for the mother being respectively provided with two double no-load voltage ratios being arranged on quarter-phase circuit The switching of line side current transformer.

3. a kind of metering switch endpoint of the wide cut with no-load voltage ratio switching current transformer according to claim 1, its feature exists In:

Described current transformer switch unit is three, for the mother being respectively provided with two double no-load voltage ratios being arranged on three-phase loop The switching of line side current transformer.

4. a kind of metering conversion of the wide cut with no-load voltage ratio switching current transformer according to one of claim 1 or 2 or 3 is whole End it is characterised in that:

The input rear portion of described current mutual inductor with high transforming ratio, the front of the second controllable switch device are simultaneously connected to and prevent Current Mutual Inductance The overvoltage inhibiting apparatus of device secondary side open circuit.

5. a kind of metering switch endpoint of the wide cut with no-load voltage ratio switching current transformer according to claim 4, its feature exists In:

Described overvoltage inhibiting apparatus be one of varistor, tvs pipe, electric capacity, capacitance-resistance series unit, 1:1 power pack or A combination thereof.

6. a kind of metering conversion of the wide cut with no-load voltage ratio switching current transformer according to one of claim 1 or 2 or 3 is whole End it is characterised in that:

Described first, second controllable switch device be one of controllable silicon, relay contact, described controllable silicon, relay contact by Control device programme-control.

7. a kind of metering switch endpoint of the wide cut with no-load voltage ratio switching current transformer according to claim 1, its feature exists In:

The output of described control device is also connected with a display and input block, described display and input block adopt liquid crystal display screen or Led screen, can achieve touch human computer conversation.

8. a kind of metering switch endpoint of the wide cut with no-load voltage ratio switching current transformer according to claim 1, its feature exists In:

The output of described control device is additionally provided with rj45 interface, in order to realize internet function.

9. a kind of metering switch endpoint of the wide cut with no-load voltage ratio switching current transformer according to claim 1, its feature exists In:

The output of described control device is also associated with the long-range sending module of gprs for output signal is sent to specified ip, or On equipment, realize networking, real-time transmission data with user backstage, and can achieve remotely control.