CN202150344U - Electronic high-voltage transformer - Google Patents

Abstract

The utility model discloses an electronic high-voltage transformer, and belongs to the field of high-voltage electronic appliances. The electronic high-voltage transformer comprises a U-shaped or transverse l-shaped capacitive primary winding, an ultra-crystallite iron core coil, a Rogowski coil, a differential transducer, an integrated terminal and the like. In the electronic high-voltage transformer, the capacitive primary winding is divided into two sections with different lengths; two unequal capacitive currents led out from the two sections are grounded through the input end of the differential transducer; the output end of the differential transducer obtains a low-voltage signal which is in direct proportion to a primary voltage; the ultra-crystallite iron core coil and the Rogowski coil sense the low-voltage signal which is in direct proportion to a primary current; and the integrated terminal converts the analogue quantity electric signals into digital quantity optical signals and provides the digital quantity optical signals for a digital measurement instrument and a microcomputer protection device. The device has the functions of a voltage transformer and a current transformer at the same time, and the intermediate low-voltage analogue quantity signals are all in a weak current category, so the electronic high-voltage transformer has safety, reliability, common-mode interference resistance, small error and high precision.

Description

The electronic type high-voltage mutual inductor

Technical field

The utility model belongs to the High-Voltage Electrical Appliances field, is used for places such as power plant, transformer station primary voltage, current conversion are become secondary voltage, electric current, and adopt digital form to digital measuring instrument or protective relaying device signal to be provided.

Background technology

Existing high-voltage mutual inductor mainly contains two types of electromagnetic type and photoelectric types, and wherein the overwhelming majority is traditional electromagnetic type, and photoelectric type quantity is emerging in the last few years technology seldom.In addition, there is document to introduce other instrument transformer scheme of combination electromagnetic type and two types of characteristics of photoelectric type (being called the combination electronic mutual inductor in this specification).

Traditional electromagnetic potential transformer utilizes electromagnetic induction principle to convert a high voltage (more than tens of kilovolts) to secondary low-voltage (about 100V); Traditional electromagnetic current transducer then utilizes electromagnetic induction principle to convert primary current (being generally more than hundreds of peaces) to the little electric current of secondary (5A or 1A).Voltage and current by the output of instrument transformer secondary sends measuring instrument or protective relaying device to through cable.Though with respect to the high voltage of primary circuit, big electric current; The 100V or the 1-5A of the output of electromagnetic transformer secondary have been low-voltage or little electric current; But with respect to the digital measuring instrument and the microcomputer protecting device that have generally adopted at present; 100V or 1-5A still belong to " forceful electric power " scope, still too " by force ", need it be transformed to once more " light current " category (such as 3V).

Therefore; Development has in the last few years played photoelectric type instrument transformer new technology; This technology adopts the property (such as tabellae dextromethorphai Hydrobromidi-Compositae effect, magneto optical effect etc.) of some material; High voltage, a big electric current are directly changed into " weak electric signal ", and, digital secondary singal are sent to digital measuring instrument and microcomputer protecting device through optical fiber through A/D (mould/number) conversion and electric light conversion.

The combination electronic mutual inductor is different with the photoelectric type instrument transformer with above-mentioned electromagnetic type, and it has utilized winding of capacitor type of traditional electromagnetic current transducer, but adopts electronic circuit cell output.It is that 99255044.0 the utility model specification and the patent No. are patent of invention specification of 200410086285.1 etc. that representational open source literature has the patent No..The patent No. is that 99255044.0 utility model patent has proposed the electric capacity core body of conventional current instrument transformer or sleeve pipe is made the voltage divider form; That is: the hollow edged electrode of innermost layer (being commonly referred to as " 0 " screen) is until the last screen of end screen constitutes high-voltage capacitance C1; The last screen of end screen constitutes low-voltage capacitance C2 with the end screen; The output of this voltage divider is received on the electronic type power amplifier, the secondary voltage (analog quantity) that output is directly proportional with primary voltage.The patent No. is that 200410086285.1 patent of invention then further becomes light signal with the secondary output transform, and outside the screen of end, is nested with no magnetic core secondary coil (Rogowski coil), is used to gather current signal.Like this, accomplish the function of voltage transformer summation current transformer simultaneously by an instrument transformer.

Above-mentioned combination electronic mutual inductor scheme; Utilized the capacitor type structure of a winding of electromagnetic current transducer to carry out voltage signal acquisition; Again through its rearmounted electronic circuit (99255044.0 utility models are called the electronic type power amplifier, and 200410086285.1 inventions are called conversion processor) output analog signal or digital signal.Its advantage is the function that an instrument transformer has made up the voltage transformer summation current transformer, and has used winding of electromagnetic current transducer of technology maturation, therefore has very high practicality.

But, also there is significantly deficiency in the technique scheme, mainly be:

1, the output voltage of capacitor voltage divider is too high, even reaches hundreds of volts, can't directly insert on the one hand conventional electronic circuit (conventional input voltage is generally about 3V), on the other hand also easily near the screen of end and lead-out wire the failure of insulation fault takes place on the way.The too high reason of capacitor voltage divider output voltage is that the capacitance of low-voltage arm C2 is big inadequately; This is caused by structure and process limitations; Because C2 is made up of end screen screen last with it; Insulation thickness between two screens is by present material and technological level is the thinnest can only accomplish 50-100 μ m, so the numerical value of C2 is restricted, and the voltage of getting on it is just than higher.Through calculating, for the 110kV instrument transformer, expect the output voltage about 3V, the insulation thickness between end screen and its last screen should drop to about 2 μ m, also can't accomplish at present.

2, the secondary of utility model 99255044.0 schemes output is analog quantity, can't be directly as the input signal of digital measuring instrument and protective relaying device.

3, patent of invention 200410086285.1 schemes; The secondary coil of its current transformer is a Rogowski coil, though this kind coil has advantages such as cost is low, the range of linearity is wide, because it does not have iron core to come boundling magnetic field; Therefore it can receive influences such as installation site, environmental condition (such as temperature, humidity) variation from the next signal accuracy of winding coupled; It is bigger finally to be reflected as transformer error, and the instrument transformer of especially electricity metering being used is difficult to meet the demands.

Summary of the invention

The purpose of the utility model is the deficiency that will overcome prior art; Invent a kind of high-voltage mutual inductor of numeral output; It can convert primary voltage and primary current into digital signal simultaneously; Can directly dock with digital measuring instrument and protective relaying device, and satisfy the requirement of the instrument transformer that electricity metering uses.

For reaching this purpose, at first utilize " U " font or winding of " one " font capacitor type high voltage to be converted to the output voltage signal (being not more than 5V) of light current category; Second; The secondary coil (Rogowski coil) of a cored secondary coil of suit and a no iron core outside the screen of the end of " U " font or a winding of " one " font capacitor type; Primary current is converted to the output voltage signal (being not more than 5V) of light current category; Cored coil is specifically designed to be measured and measuring instrument, and Rogowski coil is specifically designed to relaying protection; The 3rd, the above-mentioned signal that is come by primary voltage and primary current conversion is inserted integrated terminal, convert the output of digital quantity light signal to.

The high-potential electrode of " U " font or a winding of " one " font capacitor type is called 0 screen, and the earth potential electrode is called the end screen.Apply voltage on 0 screen and be primary voltage Uin.The electric capacity that forms from the last screen of 0 screen to end screen is C1.The end is shielded and is divided into two sections (these are the ground floor implications of " difference ") that are uneven in length, long one section and the last screen formation of end screen capacitor C 21, short one section and the last screen formation of end screen capacitor C 22, obviously C21＞C22.Draw two leads respectively by two sections of end screen; Two leads are through differential transformation device ground connection; The output current of differential transformation device is that doubly (this is the second layer implication of " difference " for the m of difference of two electric currents of input; M is called the conversion multiple), the output of differential transformation device is connected to capacitor C3, and the last voltage of C3 is output voltage U out.Definition k=Uin/Uout is a voltage ratio, can derive:

$k=\frac{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="HSA00000475653800011.png,HSA00000475653800031.png"\; state="\{\{state\}\}">C</figure-callout>}1+C21+C22}{C21-C22}\&CenterDot;\frac{\mathrm{<figure-callout\; id="3"\; label="C"\; filenames="HSA00000475653800011.png,HSA00000475653800013.png"\; state="\{\{state\}\}">C</figure-callout>}3}{\mathrm{<figure-callout\; id="1"\; label="mC"\; filenames="HSA00000475653800011.png,HSA00000475653800031.png"\; state="\{\{state\}\}">mC</figure-callout>}1}$

Can find out that voltage ratio k and capacitance difference C21-C22 are inversely proportional to, therefore as long as two segment length difference of end screen are less, the k value just can be bigger, promptly for certain Uin, can make Uout=Uin/k be in the light current category.

Cored secondary coil of suit and a Rogowski coil outside the screen of the end of a winding of capacitor type, cored coil is specifically designed to be measured and measuring instrument, adopts the ultracrystallite iron core, and Luo-coil is specifically designed to relaying protection.These two secondary coils are connected to sample resistance respectively, are used for the current signal that conversion comes is converted into the voltage signal of light current category, and sample resistance can fit together with these two secondary coils, also can place in the following integrated terminal.When sample resistance and secondary coil fit together, secondary coil output be voltage signal; In the time of in sample resistance places integrated terminal, what secondary coil was exported is current signal.

The signal of the signal of differential transformation device output and secondary coil output inserts the corresponding input of integrated terminal respectively.Integrated terminal places in the metallic shield box, and it comprises mould/number conversion function, electricity/light translation function at least, the signal of differential transformation device output and the conversion of signals of secondary coil output is become digital quantity, and export with light patterns.

In sum, the utility model relates to a kind of electronic type high-voltage mutual inductor, comprising: " U " font or winding of " one " font capacitor type; Measure special-purpose cored coil; Protect special-purpose Rogowski coil, differential transformation device, integrated terminal; It is characterized in that: the end screen of a winding of capacitor type is divided into not isometric two sections; The lead-out wires of two sections end screens connect the differential input end of differential transformation device, and the voltage transformer terminal of the output termination integrated terminal of differential transformation device is measured outside the end screen that special-purpose cored coil is enclosed within a winding of capacitor type; The output of measuring special-purpose cored coil connects the Verification of Measuring Current Transformer terminal of integrated terminal; Protect special-purpose Rogowski coil to be enclosed within outside the end screen of a winding of capacitor type, protect the output of special-purpose Rogowski coil to connect the protective current transformer, terminal of integrated terminal, integrated terminal becomes the digital quantity light signal with the analog quantity electrical signal conversion of voltage transformer terminal, Verification of Measuring Current Transformer terminal, protective current transformer, terminal.In addition, the utility model electronic type high-voltage mutual inductor can also have following characteristic: 1, the end of a winding of capacitor type screen is divided into more than two sections or two sections.2, have overlappingly on two sections of a winding of capacitor type end screen positions, have between two sections end screens of overlapping part to increase around insulation.3, the Primary Conductor in winding of capacitor type is made up of the alloy aluminum pipe and the aluminium bar that are nested together, between aluminium bar and aluminum pipe insulating material is arranged.4, the differential transformation utensil has iron core-closed.5, differential transformation device output is connected to capacitor.6, the iron core of the special-purpose cored coil of measurement is the ultracrystallite iron core, measures special-purpose cored coil and is connected to resistance.7, the special-purpose Rogowski coil of protection is connected to resistance.The utility model is compared with existing combination electronic mutual inductor technical scheme and is had the following advantages:

1, differential transformation device output voltage is low, can directly insert electronic circuit (such as integrated terminal);

2, screen difference in end can suppress the common mode disturbances of winding two an arms introducing, such as the capacitance current that comes from the coupling of external insulation leakage current, because two arms symmetry can be cancelled each other;

3, the current transformation precision be can guarantee with the ultracrystallite iron-core coil, measurement and charging guaranteed accurately; Because its saturation characteristic can limit output voltage when short circuit current, protection is measured and measuring instrument simultaneously; With Luo-coil the used for relay protection signal is provided, cost is low, the range of linearity is wide;

4, adopt the output of digital quantity light signal, the error that has not had transmission course to cause has played primary equipment and the effect of measuring control appliance isolated simultaneously.

Description of drawings

Fig. 1 is an electronic type high-voltage mutual inductor sketch map, among the figure: 1-high-field electrode (0 screen), 2-intermediate capacitance screen; 3 ', 3 "-be divided into two sections end screen, 4-differential transformation device, 8-ultracrystallite iron-core coil; 9-Rogowski coil, 10-integrated terminal, 16-annular core or other shape iron core-closed; 17-difference input coil, 18-difference output winding, 19-integrating capacitor C3.

Fig. 2 is the equivalent circuit diagram that end screen difference connects, among the figure: 4-differential transformation device.

Fig. 3 is that the insulation of two sections end screen lap-joints increase around sketch map, among the figure 3 ', 3 "-being divided into two sections end screen, 15-increases around insulation.

Fig. 4 is a practical implementation example schematic, and winding of capacitor type is " U " shape oil-impregnated paper insulation, among the figure: 4-differential transformation device, 5-insulator; Winding of 6-oil-impregnated paper insulation capacitor type, 7-transformer oil, 8-ultracrystallite iron-core coil; The 9-Rogowski coil, 10-integrated terminal, 11-fuel tank.

Fig. 5 is another practical implementation example schematic, and winding of capacitor type is " U " shape dry insulation, among the figure: 4-differential transformation device; 8-ultracrystallite iron-core coil; The 9-Rogowski coil, 10-integrated terminal, 12-silicon rubber full skirt; Winding of 13-dry type compound inslation capacitor type, the 14-base cabinet.

Embodiment

Referring to Fig. 1, the utility model electronic type high-voltage mutual inductor comprises high-field electrode (0 screen) 1, intermediate capacitance screen 2, is divided into two sections end screen 3 ' and 3 ", differential transformation device 4, ultracrystallite iron-core coil 8, Rogowski coil 9, and integrated terminal 10.The high-field electrode 1 outer insulating material that twines is laid intermediate capacitance screen 2 in position in the winding process, intermediate capacitance screen 2 can have a plurality of; Last capacitance plate (i.e. end screen) is divided into two section 3 ' and 3 that is uneven in length ", and respectively 3 ' and 3 " on tie up and draw lead, last like this winding of capacitor type that shields difference has just been made.Laying two sections end screens 3 ' and 3 " time; should be noted that the insulation between them, a kind of feasible scheme is as shown in Figure 3, lay earlier weak point 3 "; 3 " increase around layer 2-3 insulation 15 with a 3 ' close end; re-lay long by 3 ', make 3 ' increase around insulation 15 outer and 3 " overlapping, overlap length 10-20mm gets final product.

In instrument transformer when assembling, is with two sections end screens 3 ' and 3 " on lead-out wire receive the differential input end of differential transformation device 4.Typical differential transformation device 4 is as shown in Fig. 1 frame of broken lines, and its input winding 17 be the coil that on iron core-closed 18, twines, the middle ground of input winding 17, and two ends are differential input end, the two ends of exporting winding 18 are connected to integrating capacitor 19.

During the instrument transformer assembling, suit ultracrystallite iron-core coil 8 and Rogowski coil 9 outside the screen of end.

Integrated terminal 10 has 3 pairs of input terminals: voltage transformer terminal, Verification of Measuring Current Transformer terminal, relaying protection Current Transformer terminal.During the instrument transformer assembling; The output signal of differential transformation device 4 is inserted the voltage transformer terminal of integrated terminal 10; The output signal of iron-core coil 8 is inserted the Verification of Measuring Current Transformer terminal of integrated terminal 10, the output signal of Rogowski coil 9 is inserted the relaying protection Current Transformer terminal of integrated terminal 10.

Fig. 2 is the equivalent circuit that end screen difference connects, and can pass through this equivalent circuit derivation voltage ratio computing formula, is used for the design of the utility model instrument transformer.

Further specify the execution mode of the utility model below in conjunction with instantiation.

Fig. 4 is a practical implementation instance of the utility model electronic type high-voltage mutual inductor.This instance instrument transformer rated voltage 110kV, rated current 2x300A, main insulation is oil-paper.The concrete operations step is following:

1) electrician's aluminum pipe of, choosing diameter 48mm, wall thickness 6mm, length overall 3400mm is as Primary Conductor; It is split into the two halves of equity; Two " semicircle pipes " are wrapped up one deck with insulating cloth tape; Again with the formation " director circle pipe " that is stitched together of two " semicircle pipes " that are surrounded by insulation, and solid with the semi-conductive cloth tape wrapping, semi-conductive cloth tape carries out equipotential with wherein one " semicircle pipe " with lead and is connected; " director circle pipe " curved " U " font that opening is slightly received, bending radius 160mm, opening part centre-to-centre spacing 260mm with bending machine.The semi-conductive cloth tape layer of this " U " font " director circle pipe " is high-field electrode (0 screen), referring to Fig. 1.

2), " U " font " director circle pipe " is fixed on the insulation bundling machine, successively hold insulating paper strip, electric screen 2 (referring to Fig. 1) in the middle of in position laying.Electric screen in the middle of this instance has 24, wherein 3,6,9,12,15,18,21,24 is large-size screen monitors, all the other are the end screen.

3) it is thick, to hold insulating paper strip 1mm in the middle of No. 24 outside the electric screen; Lay segmentation end screen 3 " (referring to Fig. 3); its length is 400mm, 3 " an end (being in that end of " U " font segmental arc) hold that 0.6mm is thick to be increased around insulation 15 (referring to Fig. 3), increase around insulated lengths 100mm; Lay another section end screen 3 ' (referring to Fig. 3), another section end screen 3 ' total length is 500+15mm, and wherein 15mm increases in insulation 15 and 3 for being pressed in " length of lap; 3 ' and 3 " on tie up lead-out wire.

4), " U " shape centre-to-centre spacing suitable for reading is put in order to 200mm, winding 6 of the above-mentioned capacitor type of making is tied up firmly, put into vacuum tank and carry out the 7x24h vacuum drying treatment with insulating cloth tape, epoxy support component etc.

5), assembling: differential transformation device 4 is fixed in the fuel tank 11, the earth connection of differential transformation device 4 inputs is connected; Integrated terminal 10 is fixed to the fuel tank outside; From vacuum tank, taking out winding of capacitor type 6 also is fixed in the fuel tank 11 immediately; The differential input end that lead-in wire is connected to differential transformation device 4 is shielded at the segmentation end of a winding 6 of capacitor type, the output of differential transformation device 4 is received the voltage transformer terminal of integrated terminal 10; Put ultracrystallite iron-core coil 8 and Rogowski coil 9, the output lead of coil 8 and coil 9 is connected respectively to the Verification of Measuring Current Transformer terminal and the protective current transformer, terminal of integrated terminal 10; Insulator 5 is installed; Through vacuum oil machine injection transformer oil 7; At last, relevant parts such as instrument transformer top no-load voltage ratio conversion element, expander, wire clamp are installed.

Fig. 5 is another practical implementation instance of the utility model electronic type high-voltage mutual inductor.This instance instrument transformer rated voltage 110kV, rated current 2x400A, main insulation is the dry type compound inslation.The concrete operations step is following:

1) the alloy aluminium bar of alloy aluminum pipe and diameter 30mm, length 3700 of, choosing diameter 50mm, wall thickness 7mm, length overall 3400mm is as Primary Conductor; The long winding of 2700mm insulation film 2mm in the middle of the aluminium bar of length 3700mm is thick, aluminium bar is penetrated in the aluminum pipe, the two ends aluminium bar respectively stretches out aluminum pipe 150mm, and each inserts each end an insulation chock between aluminum pipe and the aluminium bar, and it is struck tightly; Aluminum pipe with wearing aluminium bar in the bending machine general curves " U " font, bending radius 180mm, opening part centre-to-centre spacing 360mm.On this " U " font conductor, twine one deck and partly lead self-adhesive tape, this semiconductive self-adhesive tape is high-field electrode (0 screen), referring to Fig. 1.

2), " U " font conductor is fixed on the insulation wrapping machine, successively hold the polytetrafluoroethylene film that applies silicone oil, electric screen 2 (referring to Fig. 1) in the middle of in position laying.Electric screen in the middle of this instance has 24, wherein 3,6,9,12,15,18,21,24 is large-size screen monitors, all the other are the end screen.

3) it is thick, to hold the polytetrafluoroethylene film 1.2mm that applies silicone oil in the middle of No. 24 outside the electric screen; Lay segmentation end screen 3 " (referring to Fig. 3); its length is 400mm; 3 " an end (being in that end of " U " font segmental arc) hold that 0.6mm is thick to be increased around insulation 15 (referring to Fig. 3), increase around insulated lengths 100mm; Lay another section end screen 3 ' (referring to Fig. 3), the total length of another section end screen 3 ' is 500+15mm, and wherein 15mm increases in insulation 15 and 3 for being pressed in " length of lap; 3 ' and 3 " on tie up lead-out wire.

4), with the multistage heat-shrink tube above-mentioned capacitor type main insulation core body is sealed, the joint of each section heat-shrink tube is coated with behind the fluid sealant overlapping, and heat shrink is accomplished sealing then; Segmentation end screen 3 ' and 3 " lead-out wire draw from the joint of heat-shrink tube; Winding 13 of the capacitor type of making places the clean dried place subsequent use.

5), assembling: differential transformation device 4 is fixed in the base cabinet 14, the earth connection of differential transformation device 4 inputs is connected; Integrated terminal 10 is fixed on the base cabinet 14 (inside and outside the casing all can); Winding 13 of capacitor type is fixed in the base cabinet 14, the differential input end that lead-in wire is connected to differential transformation device 4 is shielded at the segmentation end of a winding 13 of capacitor type, the output of differential transformation device 4 is received the voltage transformer terminal of integrated terminal 10; Put ultracrystallite iron-core coil 8 and Rogowski coil 9, the output lead of coil 8 and coil 9 is connected respectively to the Verification of Measuring Current Transformer terminal and the protective current transformer, terminal of integrated terminal 10; Install the loam cake of base cabinet 14, two arms and the loam cake of a winding 13 of capacitor type fixed; Adhesive is applied to the endoporus of silicon rubber full skirt 12 and the full skirt cover is installed on two arms of a winding 13 of capacitor type; At last, relevant parts such as instrument transformer top no-load voltage ratio conversion element, rain cover, wire clamp are installed.

Claims (8)

1. electronic type high-voltage mutual inductor; Comprise: " U " font or winding of " one " font capacitor type, measure special-purpose cored coil, protect special-purpose Rogowski coil; The differential transformation device; Integrated terminal is characterized in that: the end screen of a winding of capacitor type is divided into not isometric two sections, and the lead-out wire of two sections end screens connects the differential input end of differential transformation device; The voltage transformer terminal of the output termination integrated terminal of differential transformation device; Measure outside the end screen that special-purpose cored coil is enclosed within a winding of capacitor type, the output of measuring special-purpose cored coil connects the Verification of Measuring Current Transformer terminal of integrated terminal, protects special-purpose Rogowski coil to be enclosed within outside the end screen of a winding of capacitor type; Protect the output of special-purpose Rogowski coil to connect the protective current transformer, terminal of integrated terminal, integrated terminal becomes the digital quantity light signal with the analog quantity electrical signal conversion of voltage transformer terminal, Verification of Measuring Current Transformer terminal, protective current transformer, terminal.

2. electronic type high-voltage mutual inductor as claimed in claim 1 is characterized in that: the end screen of a winding of capacitor type is divided into more than two sections or two sections.

3. electronic type high-voltage mutual inductor as claimed in claim 1 is characterized in that: have overlappingly on the screen positions, two sections of a winding of capacitor type ends, have between two sections end screens of overlapping part to increase around insulation.

4. electronic type high-voltage mutual inductor as claimed in claim 1 is characterized in that: the Primary Conductor in winding of capacitor type is made up of the alloy aluminum pipe and the aluminium bar that are nested together, between aluminium bar and aluminum pipe insulating material is arranged.

5. electronic type high-voltage mutual inductor as claimed in claim 1 is characterized in that: the differential transformation utensil has iron core-closed.

6. electronic type high-voltage mutual inductor as claimed in claim 1 is characterized in that: differential transformation device output is connected to capacitor.

7. electronic type high-voltage mutual inductor as claimed in claim 1 is characterized in that: the iron core of measuring special-purpose cored coil is the ultracrystallite iron core, measures special-purpose cored coil and is connected to resistance.

8. electronic type high-voltage mutual inductor as claimed in claim 1 is characterized in that: protect special-purpose Rogowski coil to be connected to resistance.

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