CN109900944A - Intelligent AC electric bridge and electrical equipment, insulating materials alternating-current parameter measurement method - Google Patents
Intelligent AC electric bridge and electrical equipment, insulating materials alternating-current parameter measurement method Download PDFInfo
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Abstract
The invention discloses a kind of intelligent AC electric bridge and electrical equipments, insulating materials alternating-current parameter measurement method, including high-tension transformer；The high-tension transformer input winding connects copped wave AC voltage adjusting unit, and high-tension transformer output winding one end is connect with product to be tested, standard capacitor one end；The product to be tested other end is connect with the first winding of current comparator one end；The output of the standard capacitor is followed by the second winding of current comparator through current transformer armature winding；First winding, the connection of the second winding；Another tie point for terminating first winding, the second winding of high-tension transformer output winding；It is divided into two-way after the secondary transformer winding output, wherein connecing capacitive balance compensation current regulation unit all the way, another way is connected after 90 degree of phase-shifting units with resistive balanced compensated current regulation unit；The resistive balanced compensated current regulation unit, capacitive balance compensation current regulation unit are connect with the tertiary winding of current comparator, the 4th winding respectively.The present invention can be used for the alternating-current parameter measurement of high-voltage electrical equipment and insulating materials test product, and anti-interference, sensitivity and precision are high.
Description
Technical field
The present invention relates to high voltage measuring technical field, in particular to a kind of full-automatic general intelligent AC electric bridge is a kind of
For measuring capacitance, inductance and the dielectric loss angle tangent of high-voltage electrical equipment and insulating materials under alternating voltage effect
The measuring device of equal electric parameters.
Background technique
In the high-voltage electricity such as insulating materials production and transformer, generator, mutual inductor, reactor, capacitor and bushing
In the design of device equipment, manufacture, operation and maintenance process, it is both needed to carry out high-voltage test, measurement electrical equipment manufacture uses
The capacitance of insulating materials, capacitivity, the capacitance of dielectric loss angle tangent and electrical equipment, inductance, dielectric loss angle are just
Cut equal alternating electric parameters.Measurement method mainly has two kinds of " balanced bridge method " and " nonequilibrium bridge method ".Wherein balanced bridge
Method has good measurement sensitivity, accuracy of measurement and noiseproof feature, but need to be balanced to measurement circuit in measurement
It adjusts, operation is more complicated, requires height to the technical level of test operator, realizes that the technical difficulty of automatic measurement is big.It is non-
Although balanced bridge method also uses bridge circuit, measurement process is completed without balance adjustment, test behaviour
Make simple, realize that the technical difficulty of automatic measurement is smaller, but measurement sensitivity, accuracy are lower, vulnerable to the other conditions in scene
Interference.
In early days, since bridge balance measurement sensitivity, accuracy are high, the ability of the anti-other condition interference in scene is strong, respectively
Kind laboratory and production scene all use balanced bridge method to carry out the measurement of the alternating-current parameters such as capacitance and dielectric loss angle tangent.I
State starts to have introduced nonequilibrium bridge measurement method in electric system, since this method exists before and after the twentieth century seventies
It does not need to be balanced adjusting in measurement process, so being achieved that automatic measurement very early.Therefore, it is pushed away soon in electric system
It sets up in a wide range and, and be applied in equipment component manufactory.But still balanced bridge is used to be surveyed in demanding laboratory
Amount.
There are Schering bridge and current comparison type electric bridge using balanced bridge method in previous measuring device.Current comparison type
Electric bridge is to be proposed by Bake (Baker) in 1962, is named as Gray and receives (Glymne) electric bridge, and Bake in 1969 proposes this
Electric bridge just develops into automatic bridge.Before 1988, China just import foreign countries this current comparison type autobalance electricity
Bridge, at that time, the selling price of this automatic bridge is as high as seven, 80 Wan Yuan.Due to the development technique of self-balancing bridge circuit
Difficulty is big, until today, it is domestic also never have it is very successful, can be suitble to laboratory (usual test product capacitance value is smaller),
It can be suitably used for the current comparision system high-precision full-automatic intelligent AC electricity that production scene uses (test product capacitance value is bigger) again
Bridge device.
The current comparison type automatic bridge of external import uses a kind of autobalance algorithm, is opened by measuring nulling winding
The amplitude and phase of road voltage, and Newton-Raphson method is used, by iterative calculation, determine in bridge balance adjustment process,
The N adjusted every time2With the correction value (balance adjustment value) of β.When such bridge balance, the current comparator adjusted repeatedly simultaneously is needed
The number of turns (N of two windings3=N2) and currentgainβ, the open-circuit voltage amplitude and phase required to nulling winding is adjusted every time
Angle is detected, and N is calculated2With the correction value of β, to N2It is adjusted repeatedly with β, until bridge balance.
It is developed in the autobalance algorithmic technique of the 1960s, is production on the basis of scientific and technological level at that time
Object.It is limited to technical conditions at that time, following defect or technology is inevitably present using the balance method of autobalance algorithm
Prejudice:
(1) bridge balance is the correction value that balance adjustment is determined according to the amplitude and phase of nulling winding open-circuit voltage.It is flat
Final stage during weighing apparatus, nulling winding NiOpen-circuit voltage be a small magnitude, small phase angle voltage signal, this letter
Number phase angle accurately measurement it is difficult, and be easy by the dry of harmonic wave, frequency fluctuation, signal distortion in voltage signal etc.
It disturbs, to influence measurement result.Especially in production scene, and the low-frequency disturbance of measurement supply frequency (50Hz) relatively
Greatly, it is difficult thoroughly to eliminate the influence of the low-order harmonic in signal using filtering measures.
(2) according to electrical bridge principle, other one timings of umber of turns, once test product winding N1The number of turns determine, bridge measurement
The range of the capacitance of test product is just restricted, and to expand measurement range, must just adjust winding N1The number of turns.
(3) it in equilibrium process, needs simultaneously to currentgainβ and comparator umber of turn N2(N3) two kinds of parameters are adjusted
Section；If it is considered that the expansion of test product measurement range, also needs to N1It is adjusted, adjustment parameter increases, and impacted factor increases
Add.Especially comparator winding N1、N2It is connected in product to be tested and standard capacitor branch respectively, impedance necessarily affects
Electric current in two branches.Therefore, the impedance where the variation of umber of turn necessarily affects it in branch influences flat in branch
Weigh electric current, to influence measurement result.
(4) during using the theory deduction of the balanced bridge of autobalance algorithm, the calculating of measurement parameter is to have ready conditions
, i.e. foundation is obtained in the case where having ignored the adjusting gain alpha of one of balanced balanced current.Domestic relevant information is to automatic
The balanced bridge of balanced algorithm is studied, and data is mentioned in the related derivation of equation of the balance method, " in derivation process
In, because the α value of multiplier is much smaller than 1, so being omitted, such branch is considered as being disconnected, and such omission is to error
It influences to need further analysis and considers." and when actual measurement, the capacitance value of test item (on-site electrical equipment) is bigger
When, α be capacitive balance electric current enlargement ratio, value must will not be too small, the capacitance swing of the test product of such bridge measurement
It will be restricted, so, ignore α and necessarily measurement error is affected.
201610840571.5 disclose a kind of electric bridge, when bridge balance, need simultaneously to the capacitive component of test product electric current
It is balanced, is not directed in the program to 90 degree of phase shift steps with resistive component.What sampling CT was obtained is pure capacity current, this
Electric current can only be balanced compensation to the capacity current of test product, and cannot be balanced compensation to the current in resistance property in test product.Institute
With not 90 phase shift, the balanced compensated electric current with current in resistance property same-phase cannot be obtained, can not by comparator it is resistive around
Group is balanced the current in resistance property of test product, and electric bridge can not be made to reach final balance.
Without phase-veversal switch between two balanced compensated electric currents of above scheme and comparator winding, thus electric bridge not can be carried out it is negative
Dielectric loss measurement can not measure the alternating-current parameter of perceptual test product.
Bridge balance adjusting method is not mentioned in above scheme, if still using the method for previous artificial balancing, i.e.,
It blindly " sounds out " repeatedly, during each sound out, changes in balance, which determines, adjusts operation, if signal becomes smaller, continues former
The direction come is adjusted, and balanced signal becomes larger, then is adjusted toward opposite direction, and the amplitude of adjusting is according to the variation amplitude of balanced signal
It determines, but without standard measure, can only sound out repeatedly.The time that this method is adjusted may especially be grown.Equalization point can even be lost
And " endless loop " is fallen into, it is unable to get measurement result.
The transformer voltage adjusting method being not directed in above scheme such as still uses the pressure regulation of electromagnetic type method, the weight of electric bridge
Amount can be than heavier.There are Schering bridge and current comparison type electric bridge two major classes using balanced bridge method in previous measuring device,
These two types of electric bridges can only measure the dielectric loss angle tangent and capacitance, permittivity value of test product., traditional Schering bridge method measurement
Equipment mainly has QS1 electric bridge, QS3 electric bridge, and current comparison type bridge method has QS19 type electric bridge etc., they are all using tune manually
Section bridge balance measures.There are AI-6000 dielectric loss measuring instrument, PH-2801 using what disequilibrium survey method measured
Dielectric loss measuring instrument etc., though this quasi-instrument is self-operated measuring unit, since its measurement is in bridge circuit non-equilibrium state
Lower progress can only be referred to as " dielectric loss measuring instrument " so generally this quasi-instrument is not known as electric bridge.Imbalance method measuring principle
And set up under conditions of the influence of partial parameters having ignored, therefore measurement sensitivity and precision be all restricted.Together
When again due to the limitation of measuring principle itself, when making this kind of equipment for field test, be easy by neighbouring charged generatrix and other
The interference of charging equipment, influences measurement result.Production scene application show the measurement data of this quasi-instrument often dispersibility compared with
Greatly, this brings difficulty to the analysis of the insulation performance in field device operational process.Therefore, a kind of interference-free, it can accurately survey
Measure the measuring device of insulation performance parameter of the insulating materials such as High-Voltage Electrical Appliances gas equipment, insulating oil under alternating voltage effect urgently
Exploitation.
Summary of the invention:
The technical problem to be solved by the present invention is in view of the shortcomings of the prior art, provide a kind of intelligent AC electric bridge and electricity
Device equipment, insulating materials alternating-current parameter measurement method improve measurement sensitivity and measurement accuracy, improve anti-interference ability.
In order to solve the above technical problems, the technical scheme adopted by the invention is that: a kind of intelligent AC electric bridge, including high pressure
Transformer；High-tension transformer output winding one end is connect with product to be tested, standard capacitor one end；The product to be tested is another
One end is connect with the first winding of current comparator one end；The output of the standard capacitor is followed by through current transformer armature winding
The second winding of current comparator one end；First winding, the second winding other end are connected with each other；The high-tension transformer output
The tie point of another termination of winding first winding, the second winding；It is divided into two after the secondary transformer winding output
Road, wherein connect all the way capacitive balance compensation current regulation unit, another way after 90 degree phase-shifting units with resistive balanced compensated electricity
Stream adjusts unit connection；The resistive balanced compensated current regulation unit, capacitive balance compensation current regulation unit pass through instead respectively
Mutually switch is connect with the tertiary winding of current comparator, the 4th winding.
5th winding of the current comparator is connect with balance indicating unit.
The balance indicating unit, capacitive balance compensation current regulation unit, resistive balanced compensated current regulation unit are equal
It is connect with measure-controlling unit.
90 ° of phase-shifting units are connect with the measure-controlling unit.
The resistive balanced compensated current regulation unit, capacitive balance compensation current regulation unit pass through reverser respectively
It is connected with the corresponding tertiary winding, the 4th winding.
High-tension transformer input winding is connected with copped wave AC voltage adjusting unit.
Correspondingly, above-mentioned intelligent AC bridge measurement high-voltage electrical equipment and insulation material are utilized the present invention also provides a kind of
Expect the method for test product alternating-current parameter, comprising the following steps:
1) high-tension transformer applies high-potting voltage, test product electric current input current ratio to product to be tested and standard capacitor
Compared with device, the electric current of the standard capacitor input current comparator after current transformer is flowed through, current transformer is to standard capacitor
Electric current sampled, obtain loss be zero pure capacity current as reference current；
2) reference current is divided into two-way, wherein being input to capacitive balance compensation current regulation unit, capacitive all the way
Balanced compensated current regulation unit is to wherein the amplitude of balanced compensated electric current is adjusted all the way；Another way is input to resistive balance
Current regulation unit is compensated, the amplitude of the balanced compensated electric current of another way is adjusted in resistive balanced compensated current regulation unit,
To complete the balance of electric bridge；
3) when the electric current of each winding of current comparator is cancelled out each other, electric bridge is in equilibrium state, according to current comparator
Umber of turn, the nominal capacitance magnitude of standard capacitor, electric bridge are in balanced compensated current regulation value when equilibrium state, further according to
Bridge balance complex number equation calculates the measured value of the AC characteristic parameter of each product to be tested, i.e. test product equivalent capacitance Cx, test product etc.
It is worth conductance Gx, test product substitutional resistance Rx, test product equivalent inductance Lx, test product dielectric loss angle tangent tg δx:
Wherein, U0For test voltage；N1、N2、N3、N4Respectively current comparator umber of turn；CnFor standard capacitor electricity
Capacity；CxFor product to be tested capacitance；RxFor product to be tested substitutional resistance；LxFor product to be tested inductance；DCFor capacitive balance compensation
Current regulation value；DRFor resistive balanced compensated current regulation value；ω is angular frequency.The above parameter and regulated value is corresponding for people
In equation, the measurement result of each parameter of test product can be obtained.Above calculate all is automatically performed during bridge measurement, and can be with
Various ways output.
In step 2), bridge balance adjusting method include: first electric bridge performance determine entire measurement adjustable range (
It is the measurement range of electric bridge) carry out " gamut search ", i.e., entire measurement range is divided into several sections, on the endpoint in section
It is balanced adjusting, determines the smallest section of balanced signal；Coarse balance is completed to adjust；Second step uses " homogenous segmentations method ",
Balance adjustment is carried out on the endpoint of each segmentation, further reduces balance adjustment section, is completed fine balance and is adjusted；It is true to second step
Each point in fixed balance section carries out balance adjustment, determines final equalization point, completes the fine tuning of balance.
In step 3), the output signal using balance indicating unit judges that bridge balance state, detailed process include: basis
The balanced signal amplitude for balancing indicating unit measurement, judges the adjustment state of balanced compensated electric current, in the above process
Each step each point of adjustment on, balance the smallest point of indication signal be closest to bridge balance point.Entirely equilibrium process is
It compensates in capacitive balance and repeatedly, is alternately adjusted between electric current and resistive balanced compensated electric current, be gradually intended to final equalization point,
It is exactly the best point of bridge balance.
Compared with prior art, the advantageous effect of present invention is that:
(1) can be used for the dielectric losses of the high-voltage electrical equipments such as transformer, mutual inductor, reactor, capacitor, capacitance,
The automatic measurement of the alternating-current parameters such as inductance；
(2) it can be used for dielectric loss, the capacitance, electricity under the effect of the liquid or solids insulating materials power-frequency voltage such as insulating oil
The automatic measurement of the alternating-current parameters such as capacity rate；
(3) since present invention employs the balance adjustment modes of self-balancing bridge circuit different from the past, i.e., using digital
Current gain adjusting method adjustment compensates electric current, and strong antijamming capability, control characteristic is good, high resolution, so that electric bridge has
There are strong antijamming capability, measurement sensitivity and the higher characteristic of measurement accuracy；
(4) present invention is connected to reverse phase between resistive balanced compensated current regulation unit and the tertiary winding of current comparator
Switch, so as to be measured to " negative dielectric loss angle tangent " by anti-phase；
(5) present invention compensates in capacitive balance and is connected to reverse phase between current regulation unit and the 4th winding of current comparator
Switch, thus inductance and test product loss measurement can be carried out to perceptual test product；
(6) present invention employs the voltages that " copped wave AC voltage adjusting " mode adjusts high-voltage test electric power, and therefore, voltage is adjusted
Convenient, installation weight considerably reduces.
(7) present invention can be used to the high-acruracy survey in laboratory, it can also be used to the electric appliance of production scene high capacitance
The test measurement of equipment.
Detailed description of the invention
Fig. 1 is structure of the invention block diagram.
Specific embodiment
Fully-automatic intelligent AC bridge provided by the invention institute as shown in Figure 1, include high-tension transformer, current comparator,
Standard capacitor, standard capacitor current sample CT (current transformer), capacitive balance compensate current regulation unit, capacity current
Reverse phase regulating switch, resistive balanced compensated current regulation unit, current in resistance property reverse phase regulating switch, balance indicating unit and measurement
Control, data processing and output unit etc..Wherein the output of high-tension transformer is connected with product to be tested, standard capacitor.It is tested
Test product low-pressure end directly and comparator in test product winding N1It is connected, the standard after the sampled CT of standard capacitor and in comparator
Capacitor winding N2It is connected.The other end of test product winding and standard capacitance winding is connected with each other and is grounded.Flow through standard capacitor
Electric current divides two-way after CT is sampled, wherein input capacitive balance compensates current regulation unit all the way, is digitized gain adjustment electricity
Road inputs capacitive balance through reverser after the amplitude of electric current is adjusted and compensates electric current winding N4.The shifted circuit of another way
Input resistive balanced compensated current regulation unit after carrying out 90 degree of phase shifts, be digitized gain adjusting circuit to the amplitude of electric current into
Resistive balanced compensated electric current winding N is inputted through reverser after row adjusting3。
When autobalance intelligent AC bridge measurement, high-tension transformer is to the product to be tested and standard capacitance in measurement circuit
Device applies high-voltage test electric power, and test product electric current directly from test product winding input current comparator, flows through the electricity in standard capacitor
It flows through after sampling CT from standard capacitor winding input current comparator, samples CT and the electric current of standard capacitor is sampled,
It obtains and the pure capacity current for being zero is lost as reference current.Reference current divides two-way, wherein being input to capacitive balance benefit all the way
Current regulation unit is repaid, the digitized gain in capacitive balance current regulation unit adjusts circuit and carries out to the amplitude of compensation electric current
It adjusts.Another way is input to resistive balanced compensated current regulation unit, the digitlization in resistive balanced compensated current regulation unit
The amplitude of compensation electric current is adjusted in gain adjusting circuit.Digital gain adjusting circuit in two units can be to the width of electric current
Value amplifies and Attenuation adjustable, has extraordinary linear characteristic.In the electric current and comparator iron core of balance instruction winding
Magnetic flux is related.Electric current in the other each windings of comparator is cancelled out each other, and electric bridge reaches balance, and the magnetic flux in comparator iron core becomes
To in zero, balances the electric current in winding and be intended to minimum state.When by bridge balance state, each umber of turn of comparator,
The capacitance value of standard capacitor, balanced compensated current regulation value can calculate test product and respectively exchange spy according to bridge balance equation
The measured value of property parameter.Measurement control, Measurement and Data Processing and output unit in Fig. 1 are mainly according to balance indicating unit
Balanced signal amplitude analyzes the adjustment state of balanced compensated electric current, and determines different current regulations based on the analysis results
Value adjust alternately, repeatedly to balanced compensated electric current, electric bridge is finally made to reach balance., measurement control, Measurement and Data Processing
And output unit is mainly used for measurement control, data analysis, measurement result output during entire bridge measurement, is finally completed
Whole measurements of electric bridge.
Reference current sampling CT in the embodiment uses DVDI-001M precision alternating voltage-electric current General mutual inductor；It is high
Pressure transformer uses HBHW10-1 high-tension transformer；Standard capacitor uses YL-50 type standard capacitor；Balanced compensated electric current tune
Save unit IT-01 type multiple-channel output current amplitude phase adjustment unit；Output unit uses embedded TPC1162Hi type computer
Display；Balance the signal amplification circuit that indicating unit uses multilevel signal amplifier composition；And current comparator then uses
SIB10-A type Multiple coil current comparator.
When measurement, copped wave AC voltage adjusting unit adjusts the output voltage amplitude of high-tension transformer to test requirements document value.Become
Test voltage is applied to the high-voltage end of test product and standard capacitor by depressor, the electric current in test product and standard capacitor respectively through than
Step-down side is flowed back to compared with device test product winding and standard capacitor winding.By compensating electric current and resistance to comparator capacitive balance
Sexual balance compensates the adjusting repeatedly of electric current, so that electric bridge is reached balance, then by the equilibrium equation of electric bridge, can acquire the survey of test product
Measure parameter value.
The relatively fixed value of the number of turns of balance winding in electric bridge, when measurement, it is only necessary to adjust and be balanced in two balance windings
The amplitude of electric current is compensated to find bridge balance point.Current phase phase in electric current and standard capacitor in one of winding
Together, compensation is balanced to the capacity current in test product winding.The electric current in electric current and standard capacitor in another winding
90 degree of phase phase difference, compensation is balanced to the current in resistance property in test product winding.Therefore, in entire equilibrium process, it is only necessary to right
A kind of parameter of the amplitude of two balanced compensated electric currents is adjusted.
Bridge balance adjust use " three-step approach ", first electric bridge performance determine entire measurement adjustable range (and electricity
The test product measurement range of bridge) " gamut search " is carried out, balanced signal amplitude smallest point near zone is determined as second step electricity
Bridge balance adjustment section is completed coarse balance and is adjusted；Second step uses " discrete method ", will be in balance adjustment point near signal smallest point
Region is determined as the adjusting section closest to bridge balance, further reduces balance adjustment section, completes fine balance and adjusts；Third
Step uses " point-by-point " adjusting method, is balanced adjusting to the equilibrium state of each point in second step balance section, determines it
Middle balanced signal smallest point, the i.e. final equalization point of electric bridge complete the fine tuning of balance.
This balance adjusting method region of search is big, is conducive to extend electric bridge to the measurement range of test product, bridge balance is received
Hold back that speed is fast, improve the measurement rate of electric bridge, to equalization point near when, then adjusted point by point, high resolution, be conducive to mention
The measurement sensitivity and measurement accuracy of high electric bridge.Entire adjustment process need to only change according to the amplitude of balanced signal, find best
Section is balanced, gradually tends to be balanced a little, does not need to measure the phase angle of balanced signal, therefore not by electric voltage frequency and electricity
The interference of the factors such as harmonic wave, wave distortion in pressure, measurement result is reproducible, measured data values are stable, measurement accuracy is high.
In actual measurement, the measurement accuracy of test product capacitance reflects electric capacity measuring up to × 0.1% ± 0.2pF of reading
The resolution ratio of sensitivity is up to 0.02pF or more；Dielectric loss angle tangent measurement accuracy up to reading reading × 0.2% ± 2 ×
10-5, reflect the resolution ratio of dielectric loss angle tangent measurement sensitivity up to 1 × 10-5More than.
Balanced compensated current regulation is using totally digitilized gain adjusting circuit, and current regulation scope is big, and tuning linearity is non-
Chang Gao.Adjusting can be amplified to balanced compensated current amplitude by adjusting circuit, can also be declined to balanced compensated current amplitude
Subtract adjusting, so balance adjustment is very convenient, the adjustable range of gain is up to 4 × 106。
Reverser is increased in capacitive balance compensation current regulation loop in electric bridge, therefore, in measurement by anti-
To switch, reverse operating is carried out to capacitive balance compensation electric current, the inductance current of test product can be carried out when perceptual test product measures
Compensation.It is that electric bridge is automatically performed according to the needs of balance that capacitive balance, which compensates electric current reverse operating, and therefore, electric bridge can be to sense
Property test product inductance and loss carry out automatic equilibrium mesaurement.
Reverser is increased in resistive balanced compensated current regulation loop in electric bridge, in measurement by reversely opening
It closes, reverse operating is carried out to resistive balanced compensated electric current.There are when certain special circumstances during test, such as product to be tested
Dielectric loss angle tangent than the dielectric loss angle tangent of standard capacitor also than hour, measured value may be negative value, that is, there is institute
It calls " negative dielectric loss ", at this moment needs to carry out reversely resistive balanced compensated electric current, electric bridge could balance.Resistive balanced compensated electric current is anti-
It is that electric bridge is automatically performed according to balance to operation, therefore, electric bridge can be in this progress " negative dielectric loss " automatic in special circumstances
Measurement.
Above-mentioned intelligent AC electric bridge, it is good through actual measurement proved, it is esy to use, safe and reliable, have very
Design requirement is fully achieved in good noiseproof feature, the measurement sensitivity and measurement accuracy of the device.
Claims (9)
1. a kind of intelligent AC electric bridge, including high-tension transformer；It is characterized in that, high-tension transformer output winding one end with
Product to be tested, the connection of standard capacitor one end；The product to be tested other end is connect with the first winding of current comparator one end；Institute
The output for stating standard capacitor is followed by the second winding of current comparator one end through current transformer armature winding；Described first around
Group, the second winding other end are connected with each other；The high-tension transformer output winding is another to terminate first winding, the second winding
Tie point；It is divided into two-way after the secondary transformer winding output, wherein connecing capacitive balance compensation current regulation all the way
Unit, another way connect after 90 degree of phase-shifting units with resistive balanced compensated current regulation unit；The resistive balanced compensated electricity
Stream adjusts unit, capacitive balance compensation current regulation unit distinguishes the tertiary winding of inverted switch and current comparator, the 4th
Winding connection.
2. intelligent AC electric bridge according to claim 1, which is characterized in that the 5th winding of the current comparator and flat
The indicating unit that weighs connects.
3. intelligent AC electric bridge according to claim 2, which is characterized in that the balance indicating unit, capacitive balance are mended
Repay current regulation unit, resistive balanced compensated current regulation unit is connect with measure-controlling unit.
4. intelligent AC electric bridge according to claim 3, which is characterized in that 90 ° of phase-shifting units and the measurement are controlled
Unit connection processed.
5. intelligent AC electric bridge described according to claim 1~one of 4, which is characterized in that the resistive balanced compensated electric current
Adjust unit, capacitive balance compensation current regulation unit passes through reverser respectively and connects with the corresponding tertiary winding, the 4th winding
It connects.
6. intelligent AC electric bridge described according to claim 1~one of 4, which is characterized in that high-tension transformer input winding and
The connection of copped wave AC voltage adjusting unit.
7. a kind of utilize intelligent AC bridge measurement high-voltage electrical equipment and insulating materials test product described in one of claim 1~6
The method of alternating-current parameter, which comprises the following steps:
1) high-tension transformer applies high-potting voltage to product to be tested and standard capacitor, and test product electric current input current compares
Device flows through the electric current of the standard capacitor input current comparator after current transformer, and current transformer is to standard capacitor
Electric current is sampled, and obtains and the pure capacity current for being zero is lost as reference current；
2) reference current is divided into two-way, wherein being input to capacitive balance compensation current regulation unit, capacitive balance all the way
Current regulation unit is compensated to wherein the amplitude of balanced compensated electric current is adjusted all the way；Another way is input to resistive balanced compensated
The amplitude of the balanced compensated electric current of another way is adjusted in current regulation unit, resistive balanced compensated current regulation unit, thus
Complete the balance of electric bridge；
3) when the electric current of each winding of current comparator is cancelled out each other, electric bridge is in equilibrium state, according to current comparator winding
The number of turns, the nominal capacitance magnitude of standard capacitor, electric bridge are in balanced compensated current regulation value when equilibrium state, further according to electric bridge
Balanced-complex equation calculates the measured value of the AC characteristic parameter of each product to be tested, i.e. product to be tested equivalent capacitance Cx, test product etc.
It is worth conductance Gx, product to be tested substitutional resistance Rx, product to be tested equivalent inductance Lx, test product dielectric loss angle tangent tg δx:
Wherein, U0For test voltage；N1、N2、N3、N4Respectively current comparator umber of turn；CnFor standard capacitor capacitance；
DCCurrent regulation value is compensated for capacitive balance；DRFor resistive balanced compensated current regulation value；ω is angular frequency.
8. the alternating-current parameter measurement method of high-voltage electrical equipment according to claim 7 and insulating materials test product, feature
It is, in step 2), bridge balance adjusting method includes: the entire measurement adjustable range determined first in electric bridge performance, i.e., electric
The measurement range of bridge carries out " gamut search ", i.e., entire measurement range is divided into several sections, carried out on the endpoint in section
Balance adjustment determines the smallest section of balanced signal；Coarse balance is completed to adjust；Second step uses " homogenous segmentations method ", to balance
The smallest Concourse Division of signal, carries out balance adjustment on the endpoint of each segmentation, further reduces balance adjustment section, completes
Fine balance is adjusted；Balance adjustment is carried out to each point in the balance section that second step determines, final equalization point is determined, completes flat
The fine tuning of weighing apparatus.
9. the alternating-current parameter measurement method of high-voltage electrical equipment according to claim 8 and insulating materials test product, feature
It is, in step 3), judges that bridge balance state, detailed process include: according to flat using the output signal of balance indicating unit
The balanced signal amplitude that the indicating unit that weighs measures, judges the adjustment state of balanced compensated electric current, in the above process
In each point of adjustment of each step, the balance the smallest point of indication signal is the point closest to bridge balance；Entire equilibrium process be
Capacitive balance is compensated and repeatedly, is alternately adjusted between electric current and resistive balanced compensated electric current, is gradually intended to final equalization point, also
It is the best point of bridge balance.
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