CN110031661A - A kind of voltage transformer being isolated with high pressure and low pressure - Google Patents

A kind of voltage transformer being isolated with high pressure and low pressure Download PDF

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Publication number
CN110031661A
CN110031661A CN201910188038.9A CN201910188038A CN110031661A CN 110031661 A CN110031661 A CN 110031661A CN 201910188038 A CN201910188038 A CN 201910188038A CN 110031661 A CN110031661 A CN 110031661A
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CN
China
Prior art keywords
voltage
low
low pressure
transformer
voltage arm
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Pending
Application number
CN201910188038.9A
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Chinese (zh)
Inventor
祝顺峰
唐福新
祝顺庆
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Zhejiang Horizon Instrument Transformers Co Ltd
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Zhejiang Horizon Instrument Transformers Co Ltd
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Priority to CN201910188038.9A priority Critical patent/CN110031661A/en
Publication of CN110031661A publication Critical patent/CN110031661A/en
Pending legal-status Critical Current

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/04Voltage dividers
    • G01R15/06Voltage dividers having reactive components, e.g. capacitive transformer
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/18Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using inductive devices, e.g. transformers

Abstract

The invention discloses a kind of voltage transformers being isolated with high pressure and low pressure, and including fixed three capacitive dividers on a mounting board, three capacitive dividers are sequentially connected adjustment unit and isolating transformer;Three capacitive divider structures are identical, are connected in series by high-voltage arm impedance and low-voltage arm impedance;The present apparatus uses the technical solution entirely different with capacitance partial pressure voltage transformer existing on Vehicles Collected from Market, and high-voltage arm is sprayed silicon rubber, ensure that the electric property of product using double capacitor cascaded structures, surface;Product is by reducing low tension capacity, to increase secondary output voltage, the first winding of weak signal low pressure isolating transformer, then the scheme of the output by secondary winding realization standard secondary singal are concatenated, make the presence of physical isolation on high-low pressure electric wiring, the safety of operation of power networks is further effectively ensured.

Description

A kind of voltage transformer being isolated with high pressure and low pressure
Technical field
The present invention relates to mutual inductor, specifically a kind of voltage transformer being isolated with high pressure and low pressure.
Background technique
Currently, the country generallys use FZW28-12 on-load switch on column, ZW20-12 breaker, intelligentized in order to meet It is required that needing to increase intelligent switching control equipment (FTU).In order to be supplied to the equipment zero sequence signal and meet overall device Originally the voltage transformer of outdoor placement is equally changed to the voltage transformer of principle of capacitive divider by the needs of miniaturization, And it is built into on-pole switch (short-circuiting device) inside, this is a main improvements of one or two fusion General layout Plans, but There are the following problems.
1) voltage transformer of current domestic principle of capacitive divider is all using one or two capacitor integral structures, entirety It is implanted to box house, and second divided voltage capacitor is larger because of capacitance and requires small volume, uses domestic electricity substantially Subclass capacity cell, service life and switch mismatch itself, and are built in cabinet gas chamber, once being damaged, replace Complexity, consuming time and cost be all that operation of power networks is difficult to receive;
2) the primary and secondary of voltage transformer is series connection voltage divider principle, and physical isolation is not present between each other, once one Secondary capacitor punctures, and will certainly feed through to secondary device.
3) cabinet of domestic pole-mounted circuit breaker is rectangular welding structure, and insulating gas disclosure risk is larger;Load is opened on column It closing and is designed using gas normal pressure, space is a pair of contradictory body in the external creepage distance of voltage transformer and narrow cabinet, Balance how to be obtained to guarantee the safety of product operation, is the key that design.
In conclusion exploitation is a external by two second part, and primary, two second part design electrical, physics every From miniaturized capacitance voltage divider principle voltage transformer, with guarantee product operational safety and can quick-replaceable, be current electricity Certainty under net one or two times fusion main trend.
Summary of the invention
The purpose of the present invention is to provide a kind of voltage transformers being isolated with high pressure and low pressure, to solve above-mentioned background The problem of being proposed in technology.
To achieve the above object, the invention provides the following technical scheme:
A kind of voltage transformer being isolated with high pressure and low pressure, including fixing three capacitive dividers on a mounting board, Three capacitive dividers are sequentially connected adjustment unit and isolating transformer;Three capacitive divider structures are identical, by height Pressure arm impedance and low-voltage arm impedance are connected in series, and high-voltage arm impedance is one small by the identical high-voltage capacitance C1 series connection of two capacitances Resistance R1 composition, the same low-voltage arm impedance is directly connected in series in the anti-group end of the high-voltage arm of three capacitive dividers, described Low-voltage arm impedance includes the low-voltage capacitance C0 being sequentially connected in series and resistance R0 one small, and low-voltage arm impedance end is grounded to be formed electrically Access.
The adjustment unit, isolating transformer and low-voltage arm impedance are arranged in parallel.
As a preferred solution of the present invention: the outer surface the high-voltage capacitance C1 sprays silicon rubber;Outside the low-voltage capacitance C0 It sets.
Compared with prior art, the beneficial effects of the present invention are: the present apparatus uses and capacitor existing on Vehicles Collected from Market The entirely different technical solution of branch pressure voltage mutual inductor, high-voltage arm spray silicon rubber using double capacitor cascaded structures, surface, protect The electric property of product is demonstrate,proved.Moreover, product can continue to run, and avoid single on Vehicles Collected from Market after single capacitor breakdown For the product of high-voltage capacitance after high-voltage capacitance punctures, high voltage scurries into secondary, operation and personnel safety band to secondary device Carry out hidden danger.Product is by reducing low tension capacity, to increase secondary output voltage, concatenation weak signal low pressure isolating transformer First winding, then the scheme of the output by secondary winding realization standard secondary singal, make existence on high-low pressure electric wiring Reason isolation, is further effectively ensured the safety of operation of power networks.Low pressure derided capacitors are external, and detection, maintenance, replacement are more quick It is convenient.
Detailed description of the invention
Fig. 1 is the structural diagram of the present invention;
Fig. 2 is circuit diagram of the invention.
1- mounting plate in figure, 2- capacitive divider, 3- adjustment unit, 4- isolating transformer.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts it is all its His embodiment, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that term " center ", "upper", "lower", "left", "right" "vertical", The orientation or positional relationship of the instructions such as "horizontal", "inner", "outside" be based on the orientation or positional relationship shown in the drawings, be only for Convenient for the description present invention and simplify description, rather than the device or element of indication or suggestion meaning there must be specific side Position is constructed and operated in a specific orientation, therefore is not considered as limiting the invention.In addition, term " first ", " the Two ", " third " is used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance.
In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, term " installation ", " connected ", " connection " shall be understood in a broad sense, for example, it may be being fixedly connected, may be a detachable connection, or integrally connect It connects;It can be mechanical connection, be also possible to be electrically connected;Can be directly connected, can also indirectly connected through an intermediary, It can be the connection inside two elements.For the ordinary skill in the art, can be understood with concrete condition above-mentioned The concrete meaning of term in the present invention.
Embodiment 1:
A kind of voltage transformer being isolated with high pressure and low pressure referring to FIG. 1-2, including be fixed on mounting plate 1 three A capacitive divider 2, three capacitive dividers 2 are sequentially connected adjustment unit 3 and isolating transformer 4;Three capacitance partial pressures 2 structure of device is identical, is connected in series by high-voltage arm impedance and low-voltage arm impedance, and high-voltage arm impedance is by the identical height of two capacitances The one small resistance R1 composition of voltage capacitance C1 series connection, the anti-group end of the high-voltage arm of three capacitive dividers 2 are directly connected in series together One low-voltage arm impedance, the low-voltage arm impedance include the low-voltage capacitance C0 being sequentially connected in series and resistance R0 one small, low-voltage arm resistance Anti- end is grounded to form electric path;When device is applied in column load switch or breaker, three capacitive dividers 2 High-voltage end (A, B, C-terminal) and the high pressure inlet wire of column load switch or breaker are directly connected to.
The adjustment unit 3, isolating transformer 4 and low-voltage arm impedance are arranged in parallel, and can effectively avoid individual component appearance Failure causes electric path short-circuit, causes high pressure and scurries out failure.
Measurement error is directly affected since high-voltage capacitance in actual use varies with temperature characteristic, so capacitance partial pressure The high-voltage arm impedance and low-voltage arm impedance of device 2 are used and are completed with material and technique.High voltage arm capacitor and low-voltage arm capacitor are answered With identical material and technique, small resistance is same material resistance in small resistance and low-voltage arm impedance in high-voltage arm impedance, therefore The temperature drift rate of high-voltage arm impedance and low-voltage arm impedance on same capacitive divider has preferable consistency.
It is calculated in actual use, due to A phase high-voltage arm impedance ZA, B phase high-voltage arm impedance ZBWith C phase high-voltage arm impedance ZC's Impedance value is equal, i.e. ZA=ZB=ZC=Z1, using double capacitance structures, so, the equivalent capacitance of high-voltage arm is C1/2,ω is mains frequency, C1For high voltage arm capacitor, R1Small resistance is hindered for high-voltage arm.The resistance of common low pressure arm It is anti-C0Capacitor, R are hindered for low-voltage arm0Small resistance is hindered for low-voltage arm.So for the first of adjustment circuit The voltage of signal input partHave:
I.e.
It can be seen that from formula (2)For the voltage exported by a certain percentage.
The input terminal voltage of isolating transformer 4 isIts output end is tap double-winding structure, it is assumed that isolation transformation 4 primary side winding the number of turns of device is N1, and the number of turns is N2 between secondary side da-dn, and load voltage value isThen there is following voltage transmitting to close System:
It can obtain:
By formula (2), (3) as it can be seen that impedance value and isolation of the voltage signal sensing ratio of the mutual inductor by capacitive divider 2 3 turn ratios of transformer codetermine, therefore the intrinsic standoff ratio that can constitute respectively to high-voltage arm impedance and low-voltage arm impedance and right The turn ratio of isolating transformer 4 is designed selection, then carries out signal fine tuning by adjusting unit, thus can be accurate Obtain residual voltage signal.
The output accuracy under high and low temperature environment in order to guarantee product is met the requirements, the high-voltage arm resistance of capacitive divider 2 Anti- and low-voltage arm impedance is completed using identical structure, identical material and identical manufacturing process, and high-voltage arm impedance is flowed through Rated current be no more than 1mA.
This project products application is up to 10kV in voltage rating, and frequency is the measurement of the three phase network residual voltage of 50Hz. When Single Phase Metal ground connection occurs, the maximum rated measurement output voltage values of the residual voltage of primary transducer are 6.5V, specified Load is, not less than 5M Ω, the accuracy of measurement of three phase network residual voltage is up to 0.5 grade.
The advantage of this design scheme is: capacitive divider 2 is double capacitor cascaded structures, one side power frequency tolerance electricity When pressing 48kV, each capacitor C1 respectively undertakes 24kV, greatly reduces the requirement to capacitive insulation ability;On the other hand, when one When breakdown fault occurs for capacitor, high voltage will be applied to an other capacitor both ends, can still run, effectively prevent height Pressure is scurried into secondary along access.Low-voltage output parallel connection isolating transformer 4, make between high-tension apparatus and secondary device formed physics every From further ensuring the operational safety of power grid.Low pressure derided capacitors are external, and detection, maintenance, replacement are more quick convenient.
2) both guaranteed secondary defeated by calculating and verification experimental verification, the selection principle research to 2 intrinsic standoff ratio of capacitive divider The intensity of signal is enough to drive isolating transformer out, and fully considers that the electric property of divider is reliable.
Product voltage ratio is 10000V/ √ 3/6.5V/3, i.e., 2664.62 times, when singlephase earth fault, secondary output is 6.5V.Since product technology parameter request accuracy is 3P grades, it is necessary to secondary in once 0.02 times of voltage rating of input Un value can be accurately exported, in order to guarantee that the output end of isolating transformer 4 can provide enough excitation currents, sets its voltage Than once holding voltage rating for 6.5*10=65V that is, in singlephase earth fault for 10:1.For this purpose, height pressure arm impedance Than for 2664.62/10=266.462.In view of resistance R1 is only for limiting capacitance discharge current, prevents capacitance damage and set It setting, R1 ' is the effect for balancing R1, for this purpose, resistance value very little can be ignored when calculating high-voltage arm and low-voltage arm impedance, Capacitive reactance is only calculated, and capacitive reactance is inversely proportional with capacitance, for this purpose,
In view of power frequency withstanding voltage is 48000V, it is up voltage8.31 times.It considers The dielectric level that high-voltage capacitance need to reach and the longtime running experience of electric system, high-voltage capacitance selection use earthenware slab Silver electrode capacitor.Limitation of the products application environment to outer dimension is taken into account, the capacitance of final high-voltage capacitance C1 is selected as 350pF, this When, the total capacitance value of high-voltage arm is 175pF, and by the calculating of formula (4), obtaining secondary capacitance is 93.261nF.
3) it is researched and developed by the weak signal isolating transformer to low-loss, high-precision, linear change, guarantees isolating transformer The precision of secondary output port is met the requirements.
Since product technology parameter request accuracy is 3P grades, it is necessary in once 0.02 times of voltage rating of input, two It is secondary accurately to export Un value, for this purpose, the weak signal isolating transformer of research and development low-loss, high-precision, linear change, is this item One of the technological difficulties of mesh product.
The end isolating transformer da-dn output voltage can be calculated by Un:
Un=4.44fN2AcB*10-4
(5)
In formula, f --- rated frequency
N2 --- vice-side winding the number of turns
Ac --- iron core effective sectional area, cm2
B --- iron core flux density
Formula (5) is as it can be seen that Un is directly proportional to vice-side winding the number of turns, iron core effective sectional area, iron core flux density, in order to meet Can have accuracy output when 0.02*Un, it is necessary to assure vice-side winding the number of turns, iron core effective sectional area, iron core flux density this three A parameter is sufficiently large.
Vice-side winding the number of turns and primary side winding the number of turns are the relationships of 1:10, and two windings are wound on iron core column, Increase vice-side winding the number of turns without limitation, 10 times of ratios of primary side winding the number of turns increase, then can cause the substantially increasing in iron core coiling space Add, and then expand the volume of product, while increasing the usage amount of copper wire, core material, brings the increase of cost.By Verification experimental verification, it is the numerical value of volume, cost and properties of product relative equilibrium that vice-side winding, which selects 1000 circles,.
The increase of area of core section Ac equally brings the increase of core material, copper wire usage amount, meanwhile, cause product body Long-pending and cost increase, for this purpose, unconfined raising area of core section is worthless.We can be calculate by the following formula iron core Sectional area:
Formula (6) increases the flux density B of core material, can reduce area of core section as it can be seen that when f, N2, Un are definite value.
In addition, can have accuracy output when due to 0.02*Un, for this purpose, the iron to select initial permeability high as far as possible Core material, in combination with the requirement of aforementioned B value, project team refers to the magnetic property data of following table typical material, by test of many times And material replacement, core material of the final choice permalloy as isolating transformer, and calculated suitably by formula (6) Area of core section.
Embodiment 2:
The difference from embodiment 1 is that the outer surface the high-voltage capacitance C1 spray silicon rubber, efficiently solve capacitor with The gap discharge problem of epoxy resin interface.
The low-voltage capacitance C0 is external, and detection, maintenance, replacement are more quick convenient.
It is obvious to a person skilled in the art that invention is not limited to the details of the above exemplary embodiments, Er Qie In the case where without departing substantially from spirit or essential attributes of the invention, the present invention can be realized in other specific forms.Therefore, nothing By from the point of view of which point, the present embodiments are to be considered as illustrative and not restrictive, and the scope of the present invention is by institute Attached claim rather than above description limit, it is intended that will fall within the meaning and scope of the equivalent elements of the claims All changes be included within the present invention.It should not treat any reference in the claims as limiting related right It is required that.
In addition, it should be understood that although this specification is described in terms of embodiments, but not each embodiment is only It contains an independent technical solution, this description of the specification is merely for the sake of clarity, and those skilled in the art answer When considering the specification as a whole, the technical solutions in the various embodiments may also be suitably combined, forms those skilled in the art The other embodiments that member is understood that.

Claims (5)

1. a kind of voltage transformer being isolated with high pressure and low pressure, which is characterized in that including three be fixed on mounting plate (1) Capacitive divider (2), three capacitive dividers (2) are sequentially connected adjustment unit (3) and isolating transformer (4);Three electricity It is identical to hold divider (2) structure, is connected in series by high-voltage arm impedance and low-voltage arm impedance, high-voltage arm impedance is by two capacitance phases The one small resistance R1 composition of same high-voltage capacitance C1 series connection, the anti-group end of high-voltage arm of three capacitive dividers (2) are directly connected The same low-voltage arm impedance is connected, low-voltage arm impedance end is grounded to form electric path.
2. a kind of voltage transformer being isolated with high pressure and low pressure according to claim 1, which is characterized in that the low pressure Arm impedance includes the low-voltage capacitance C0 being sequentially connected in series and resistance R0 one small.
3. a kind of voltage transformer being isolated with high pressure and low pressure according to claim 1 or 2, which is characterized in that described Adjustment unit (3), isolating transformer (4) are arranged in parallel with low-voltage arm impedance.
4. a kind of voltage transformer being isolated with high pressure and low pressure according to claim 1 or 2, which is characterized in that described The outer surface high-voltage capacitance C1 sprays silicon rubber.
5. a kind of voltage transformer being isolated with high pressure and low pressure according to claim 2, which is characterized in that the low pressure Capacitor C0 is external.
CN201910188038.9A 2019-03-13 2019-03-13 A kind of voltage transformer being isolated with high pressure and low pressure Pending CN110031661A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910188038.9A CN110031661A (en) 2019-03-13 2019-03-13 A kind of voltage transformer being isolated with high pressure and low pressure

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910188038.9A CN110031661A (en) 2019-03-13 2019-03-13 A kind of voltage transformer being isolated with high pressure and low pressure

Publications (1)

Publication Number Publication Date
CN110031661A true CN110031661A (en) 2019-07-19

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Country Status (1)

Country Link
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