CN209086326U - For determining the equipment and kilowatt-hour meter of the transmission function of current measurement arrangement - Google Patents
For determining the equipment and kilowatt-hour meter of the transmission function of current measurement arrangement Download PDFInfo
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Abstract
This disclosure relates to the equipment and kilowatt-hour meter of the transmission function for determining current measurement arrangement.One of the technical problems to be solved in the utility model is to provide improved for determining the equipment and kilowatt-hour meter of the transmission function of current measurement arrangement.The equipment includes current transformer, the current transformer is arranged to measure the first electric current passed through along the first conductor in use, the equipment includes signal source and processing equipment, the signal source is arranged to supply reference signal, so that in use, the output of the current transformer includes the current reference signal component as caused by the reference signal, and the processing equipment is arranged to receive the output and extracts the reference signal to estimate the transmission function of the current transformer.By the utility model, may be implemented improved for determining the equipment and kilowatt-hour meter of the transmission function of current measurement arrangement.
Description
Technical field
This disclosure relates to current measure device and ammeter, such as kilowatt-hour meter.
Background technique
The electric current of the consumption such as measuring device, building, factory is usually required, or is measured along distribution system along conductor
By electric current.
Various current transformers can be used for measuring electric current.Current diverter, i.e. resistance in insertion current flow path, lead to
It crosses and electric current flowing is converted into the voltage in the measurement of current divider both ends to provide the indirect measurement to electric current.The allusion quotation of current diverter
Type is applied to be measured including overcurrent protection and power consumption.In use, the current divider of known resistance is provided in current flow path.
The voltage at current divider both ends is proportional to the resistance of the electric current and current divider that flow in current divider.
In order to keep current measurement accurate, the resistance of current divider at least needs to reach required precision.It is arranged further, it is necessary to take
The self-heating for applying to ensure current divider will not be such that measurement accuracy deteriorates.For medium or high current, current divider needs to have very low
Resistance.Furthermore, it is necessary to the resistance of current divider will not with the time for example due to burn into self-heating, over-voltage effect, thermal cycle or its
Its environmental condition and deteriorate.
Alternative using current diverter is using power pack or similar inductosyn, such as Luo Ke
Paderewski coil (Rogowski coil).The shortcomings that this power pack or Rogowski coil is that they cannot be used for
Measure DC current.Rogowski coil it is a further drawback that for give size electric current, the output of this device with
The frequency of electric current proportionally increases.This it could mean that solve this problem unless steps are taken, and otherwise harmonic wave divides in electric current
The contribution of amount may be overestimated.However, the advantages of this inductosyn is, it is isolated with current-carrying conductor maintenance, thus
Higher operational safety is provided, device is even allowed for retrofit around operation conductor.It, will by using loading resistor
The electric current that electric current by flowing through measured conductor incudes in power pack is converted to voltage.Accurate determine is flowed in measured conductor
Dynamic electric current needs to know the transmission function and loading resistor of power pack.For Rogowski coil, do not need to bear
Carry resistor.
Other magnetic sensors are known, such as hall effect device, magnetoresistive sensor etc..There is provided one kind can be reliable
The equipment whether transmission function of ground monitoring current mutual inductor and indicator current mutual inductor changes over time will be advantageous.Here
The equipment of description is suitable for being used together with any this current transformer.However, for simplicity, implementation described herein
Example, which will focus mainly on using current divider, measures electric current, but description is also used to the embodiment of induction type current-sensing.
By suitably modified embodiment technology, technology discussed here may be equally applicable for being applied to fluid flowing survey
Amount and metering system.
In electric power metering system, it is also desirable to check the performance of voltage attenuator to confirm its transmission function.
Utility model content
One of the technical problems to be solved in the utility model is to provide improved for determining the transmitting of current measurement arrangement
The equipment and kilowatt-hour meter of function.
One aspect according to the present utility model provides a kind of for determining setting for the transmission function of current measurement arrangement
Standby, in the first embodiment, the equipment includes current transformer, the current transformer be arranged in use measure along
The first electric current that first conductor passes through, the equipment include signal source and processing equipment, and the signal source is arranged to supply ginseng
Signal is examined, so that in use, the output of the current transformer includes the letter of the current reference as caused by the reference signal
Number component, the processing equipment are arranged to receive the output and extract the reference signal to estimate the current transformer
Transmission function.
In a second embodiment, the size of the reference signal has given value, so that according to the reference signal
Size and the current reference signal component are known to calculate the transmission function of the current transformer.
In the third embodiment, the current transformer is calibrated during calibration steps, and the processing equipment is supervised
Survey the change of the transmission function of the current transformer after calibrating.
In the fourth embodiment, the reference signal is the electric current that interval applies, and makes it possible to intermittently determine the biography
Delivery function.
In the 5th embodiment, the amplitude response of the reference signal in measured load current but it is variable.
In the sixth embodiment, the equipment is arranged to estimate the size of first electric current.
In the seventh embodiment, the current transformer is current diverter.
In the eighth embodiment, the current transformer is inductosyn.
In the 9th embodiment, the equipment includes the second current sensor for being arranged to measure first electric current, with
And it is arranged to subtract the subtracter of the output of second current sensor from the output of the current transformer.
In the tenth embodiment, the equipment further includes at least one extra current sensor, to measure at one or more
The electric current flowed in a extra conductor.
In the 11st embodiment, the equipment further includes the voltage being connected between first conductor and reference mode
Attenuator, and the tension measuring circuit of the impedance connection across the voltage attenuator, the equipment further includes voltage signal
Source and processing equipment, the voltage signal source are arranged to supply voltage reference signal, to repair between the first value and second value
Change the voltage at the reference mode, so that the output of the voltage attenuator includes the electricity as caused by the voltage reference signal
Pressure reference signal component, the processing equipment, which is arranged to, receives the output, extracts the voltage reference signal and estimates institute
State the transmission function of voltage attenuator.
In the 12nd embodiment, the processing equipment is also arranged to estimate the voltage of first conductor.
In the 13rd embodiment, the voltage reference signal is applied intermittently, so that the transmitting of the voltage attenuator
Function is intermittently updated.
In the 14th embodiment, the equipment further includes the communication gate for transmitting data to remote computer.
In another aspect of the present disclosure, a kind of kilowatt-hour meter including the equipment in above-mentioned first embodiment is provided.
In the another aspect of the disclosure, a kind of kilowatt-hour meter including the equipment in above-mentioned 11st embodiment is provided.
In one embodiment, the kilowatt-hour meter further include current measuring transformer in energized conductor and neutral conductor and
Processor, the processor are arranged to issue police when the measured value for charging electric current and neutral current differs by more than predetermined threshold
Report.
In one embodiment, the kilowatt-hour meter is suitable for operating with three phase mains.
In one embodiment, the rate of change of monitoring current mutual inductor response, and sent out if rate of change is more than threshold value
Alarm out.
One of the beneficial effects of the utility model are to provide improved for determining the transmission function of current measurement arrangement
Equipment and kilowatt-hour meter.
Detailed description of the invention
Only describe implementation of the disclosure example by way of non-limiting example with reference to the drawings, in the accompanying drawings:
Fig. 1 is the perspective view of power consumption table；
Fig. 2 is the schematic diagram of power consumption table and its inclusion in power distribution circuit；
Fig. 3 is the diagram for showing the component for the current measurement circuit for constituting embodiment of the disclosure, and component can be set
It sets in power consumption table；
Fig. 4 is the circuit diagram according to the circuit for generating measurement electric current of the introduction of the disclosure；
Fig. 5 is the measurement improved using the first and second current diverters for load current signal according to the disclosure
The circuit diagram of the current measurement circuit of the extraction of signal；
Fig. 6 is the circuit diagram according to the voltage attenuator of the disclosure；
Fig. 7 is the circuit diagram of more detailed voltage attenuator and measuring circuit；
Fig. 8 shows using the first and second attenuators the voltage for improving the extraction of the measuring signal for voltage measurement
Measuring circuit；
Fig. 9 shows the alternative structure of the current sense device of the introduction according to the disclosure；
Figure 10 shows a part of the current measurement circuit for being used together with three phase mains；With
Figure 11 shows the current measurement circuit using induction type current transformer.
Specific embodiment
Fig. 1 is the perspective view for constituting the electronic electricity meter of embodiment of the disclosure.Usually there is electrification with 10 specified instrument
Conductor 12 and neutral conductor 14, instrument 10 is connected to the electricity of such as national national grid or local electricity generation system etc by they
Source.Other energized conductor 22 and neutral conductor 24 extends from instrument towards the load such as home dwelling, factory.Instrument 10
It can operate to measure the electric current flowed between power supply and load.It may be displayed on display 26 by the magnitude of current that load is drawn
Or it is sent back by suitable communication interface 27 (such as radio modem or wireline interface or even power line communication)
Monitoring station.In general, the electricity that electrical supplier consumes user is interested.Therefore, usual instrument 10 also measures between conductor 12 and 14
Supply voltage, and calculate using it the instant electrical power that user is consuming.Instant electrical power in given time period and previously
The consumption total electricity of estimation is summed, and instrument shows the operation total amount of the electric power of user's consumption, usually with kilowatt-hour shape
Formula is shown.Total operation kW hours is shown usually on the display 26 in instrument 10.Instrument can also be measured back to power supply
Electric power.The data can be transferred to monitoring and/or charging entity by suitable communication plan.
Fig. 2 has schematically illustrated instrument 10 and has been positioned to monitor the electrification electricity passed through between conductor 12 and 22
Stream, conductor 12 and 22 respectively indicate distribution side " electrification " and load-side " electrification ".Then it is normally provided by the electric current of instrument
To the distributing module 30 comprising busbar 32, the busbar 32 connects with multiple switch, fuse or breaker 35,36,37 and 38
It connects, the multiple switch, fuse or breaker 35,36,37 and 38 provide current flow path, respective load to respective load
E.g. in the ring main of family's premises, lighting circuit, shower and cooker.
Instrument 10 is returned to, it includes current measurement channel, and the current measurement channel includes current measuring transformer and place
Circuit 42 is managed, current divider 40 of the current measuring transformer for example in the path of energized conductor 12, processing circuit 42 is for receiving
40 both ends of current divider generate voltage and provide current signal to data processor 50.Instrument 10 further includes voltage channel,
Wherein tension measuring circuit 52 measures the voltage between energized conductor and neutral conductor and provides voltage to data processor 50
Estimation.
The circuit 42 and 52 of electric current and voltage channel can respectively include for filtering out parasitic noise or other out-of-band interferences
Filter.Circuit 42 and 52 can also include variable gain amplifier, and the variable gain amplifier is operable to respond to
Change gain therein in the signal from data processor 50.The channel can also include corresponding analog-digital converter or
Person can share the analog-digital converter between them.In circuit filter (such as frequency overlapped-resistable filter or in which other groups
Part (for example, if integrator) when current sensor is Rogowski coil) may introduce in the signal processing phase or
Time migration.Therefore circuit 42 and 52 also may include time alignment device, such as the storage of shift register or other forms
Device, to ensure that instantaneous voltage measurement is aligned with corresponding transient current time of measuring.
Fig. 3 illustrates in greater detail the embodiment in current measurement channel 42.As shown in Fig. 2, shunt resistance device 40 is set
It sets in conductor 12, conductor 12 carries the electric current I from power supply to loadL.Load current ILIt can be DC current or alternating current
Stream.Load current ILIt can also change over time.The electric current for flowing through shunt resistance device 40 is converted into and indicates in conductor 12
Electric current flowing voltage VC.Voltage VCIn the following manner with electric current ILIt is related:
VC=IL×RSEquation 1
Wherein:
IL=load current
VCThe voltage at=shunt resistance device both ends
RSThe resistance of=shunt resistance device.
Power consumption table usually requires that the measurement of the electric power of consumption is known as better than 0.1 or 0.2%.This means that shunt resistance device
40 resistance also needs to be known as at least precision, and actually more to allow by inaccurate, the quantization in voltage channel
The mixing of error caused by error etc., which is still fallen within, to be allowed in limitation, for example, the limitation of 0.1% precision.
The resistance of resistor 40 can be determined by the factory calibration during the construction of instrument 10.However, this is not
Guarantee that resistance 40 will not deteriorate within its service life.The disclosure teaches how the transmission function (for example, resistance) of monitoring current divider
Change.
As replacement embodiment, the manufacturer of ammeter may not want that and be calibrated during fabrication, and this calibration
Can later or scene complete.The instrument for wanting field calibration for the component that the disclosure allows a part used as instrument to provide
The current measurement performance of table.
In order to determine the resistance of shunt resistance device 40, perhaps shunted as a part of initial calibration procedure or confirmation
Resistance does not change over time after initial factory calibration, needs that current known is made to pass through current divider.But by ammeter from matching
It takes out in circuit it is isolated, allows to be unsuitable by known electric current, and not typically possible.Cause
This, in order to solve this problem, the disclosure includes that can be applied to shunt resistance device 40 for generating to measure its resistance
Current known IMOther circuit 60.Measurement electric current IMIt is changing currents with time, therefore can be write as and be superimposed upon through current divider 40
Load current ILOn IM(t).Therefore, the voltage V at voltage measurement subsystem 62CIncluding the load current by current divider
ILWith measurement electric current IMThe sum of.If measuring electric current IMTime to time change in a known way, no matter the measurement electric current is true in advance
Fixed or measured, then it can extract only by measurement electric current IMFlowing caused by component of voltage.If known measurement electricity
Flow IMEnough precision are known as, then can also determine the transmission function (being in this example resistance) of current divider, and similar
Ground can also determine the transmission function for acting on the signal processing circuit of the voltage from current divider.
Electric current IMIt can be generated by any suitable electric current generating device.
Fig. 4 is for generating controllable measurement IMEquipment one embodiment circuit diagram.Equipment shown in Fig. 4 includes
Precision resistor 70 is connected in series in positive supply rail+V with p-type FET 72SWith negative (or zero) power rail-VSBetween.P-type FET
72 source node is connected to positive supply rail+VS.The grid of p-type FET 72 is connected to the output of operational amplifier 74, and p-type
The drain electrode of FET 72 is communicatively connect with 70 electric current of resistor.Optionally, as shown in Figure 4, cascode transistors 75 can be with
It is inserted between the drain electrode of transistor 72 and resistor 70 and with constant grid voltage VbiasBiasing.The cascade crystal
The drain voltage that the purpose of pipe 75 is to maintain p-type FET 72 is constant, so that its operation be protected to rely on effect from certain voltages
It influences.
The anti-phase input of operational amplifier 74 is connected to one end of resistor 70.Amplifier 74 non-inverting input connection with
Receive the current demand signal for example from digital analog converter 76.Operational amplifier 74 and 72 co-operating of transistor are to adjust stream
The electric current of precision resistor 70 is crossed, so that the voltage at the node 78 at one end of resistor 70 is provided with by digital analog converter 76
It is identical to the voltage of the non-inverting input of operational amplifier 74.Therefore, if the voltage logarithm mode converter 76 at node 78 mentions
The precision of confession is known, and the resistance of resistor 70 is known as desirable value since it is precision resistor, then flows through
The electric current of transistor 72 is known and is controlled by feedback loop to match or reach and node 78 is maintained at required voltage institute
Any value needed.Transistor 72 is matched with other transistor 82.The grid of transistor 82 is connected to the grid of transistor 72, and
And the source electrode of transistor 82 is maintained at the identical voltage of the source electrode of transistor 72.Therefore, the effect of two transistors is to pass through
Identical electric current, or alternatively, by by transistor size with respect to scaling and the electric current that sets, this is for constructing electric current
It is well known for the technical staff of mirror.Cascode transistors 85 protect transistor 82 from seeing the voltage at its drain electrode
Any change, and it is reliably known and can be used for generating measurement electric current I therefore to flow through the electric current of transistor 82M。
In use, DAC 76 can be used for exporting " zero " value, so that it is guaranteed that measurement electric current does not flow within the most of the time
It is dynamic.However, periodically or if necessary to which continuously, DAC 76 can be driven, with the word sequence of change so as to
The mode known modulates measurement electric current.If measurement electric current can be accurately measured, electric current will be measured by, which not needing, is set as specific
Value or value range.Thus, for example, transistor 82 can be directly controlled by DAC 76, and precision resistor 70 may be coupled to
The drain electrode of transistor 82 or the source electrode of transistor 82, and the voltage that 70 both ends of precision resistor generate can pass through difference modulus
Converter directly measures, to measure the size of measurement electric current.
In general, measurement electric current IMThan load current ILIt is much smaller.For example, it may be desired to which load current falls in 0 to 100 amperes
In the range of.But measurement electric current usually only can be within the scope of mA.Therefore, it can be seen that compared with momentary load current signal,
It is much smaller that variable signal caused by electric current is measured as time-varying.
A kind of method for extracting measuring signal is be averaged for a long time to it, such as using lock-in amplifier or similar to setting
It is standby to carry out hundreds of circulations.Interchangeable method is filtered to signal, so as to by the frequency for measuring electric current preferentially select to
Signal at the frequency of load current.Accomplish this point, measurement electric current, which is likely to be positioned at, can not wherein it is expected to think highly of oneself
At the frequency for carrying the interference of current harmonics or load current fundamental wave.However, in order to further help to restore measuring signal, measurement letter
It number can be quick, make it possible to the region being moved in the frequency band that controller has determined that interference is minimized.
In some embodiments, the size for measuring electric current can increase as load current increases, so as to what will be limited
Current rate is maintained in limits value.Regardless of load current (if load current maintains the maximum opereating specification of circuit
It is interior), time substantially constant needed for estimated transfer function can be kept in this way.
Other than technology described above, the estimation of load current can be formed, then from shunt resistance device both ends
The estimation of load current is subtracted in the copy of the signal of generation, thus leaves measuring signal and any of load current signal remains
Remaining part point, arrives the data processing circuit for determining the transmission function of shunt resistance device for rendering.It is illustrated in greater detail in Fig. 5
This arrangement.Here there is provided two shunt resistance devices for being labeled as S1 and S2.For convenience, they are shown as
It connects in energized conductor 12.But as long as no generation earth leakage, so that it may which the flowing of expectation electric current conductor 12 is led with electric current
Body 14 matches, then current divider S1 and S2 can be to provide one in energized conductor, and one in neutral conductor, or not
It too may be both in neutral conductor.Current divider S1 and S2 do not need to be prepared to value having the same, because from current divider
The relative size of derived signal can be scaled by variable gain amplifier and/or variable attenuator, so that they are each other
Matching.However, for convenience's sake, it may be desirable that their nominal values having the same.
The voltage at the first both ends current divider S1 is as indicating that the first voltage of the embodiment of circuit 62 shown in Fig. 3 measures electricity
Road 62a measurement.The voltage at the both ends current divider S2 is measured by other tension measuring circuit 62b, circuit 62b nominally with circuit
62a is identical.In fact, if necessary, single circuit 62 can be used in a time multiplexed manner.Shown in fig. 5
In arrangement, such as the measurement current generator 60 with reference to disclosed in Fig. 3 and Fig. 4 is provided and is arranged to only provide to current divider S2
Measure electric current.
Therefore, it can be seen that the voltage at the both ends S1 is proportional to load current, and the voltage at the both ends current divider S2 and load
The sum of electric current and measurement electric current are proportional.Therefore, load current is all common for both measurements.Therefore, it follows that
The voltage that the both ends S1 are subtracted from the voltage at the both ends S2 should theoretically lead to the only voltage comprising measuring current contribution.Therefore, may be used
To more accurately determine the voltage at the both ends S2 as caused by measurement electric current, and if measure electric current IMIt is known that then can be more smart
The transmission function for really determining S2, because the load current signal for effectively serving as noise when determining the transmission function of S2 is present
It is removed from the operation or suppressed.
Each voltage measurement unit 62a and 62b include positioned at corresponding difference A/D converter 100a and 100b input it
Preceding frequency overlapped-resistable filter 64a and 64b.
A part as electric power (electric degree) table, it is also necessary to know supply voltage.In general, model of the supply voltage in several hectovolts
In enclosing, and in order to make analog-digital converter be capable of handling voltage, while maintaining in its specified opereating specification, voltage need by
Decay to only several volts or lower.Voltage attenuator generally includes the resistor of two series connections, and analog-digital converter measures wherein
The voltage at one resistor both ends.If the value of resistor be it is well known, then known to attenuation rate is also.However, with electricity is provided
Stream current divider is the same, and attenuating resistor may have nominal value, but due to manufacturing tolerance and other variations, these will scatter.
Therefore it is required to confirm the pad value provided by attenuator or at the scene calibrated attenuator.Such as due to corrosion or other environment
Factor or over-voltage events, such as be struck by lightning, even if this cannot guarantee that during fabrication using expensive calibration cartridge for calibrated attenuator
The value of resistor in attenuator remains unchanged during its operation lifetime.Therefore it is required to the operation lifetime phase in dynamometer instrument
Between confirm attenuator transmission characteristic.
Fig. 6 is the electricity for being generally designated as 140 for the voltage that monitoring is typically connected at the voltage monitoring node 150 of conductor 12
Press the schematic diagram of attenuator.Attenuator includes the first and second resistors 152 and 154 for being respectively provided with value R1 and R2.Resistor
152 have the first end for being connected to node 150 or node and are connected to the second end or node of measuring node 160.Second resistance
Device 154 is connected to second section of one of two voltage with having the first node for being connected to measuring node 160 and the property of can choose
Point 161.Typically but optionally, one of voltage is the local ground connection indicated by power rail 152 or zero volt power supply.Second
Voltage VMIt can be fixed or the voltage of time-varying, can be selected by the way that node 161 to be connected to the switch 162 of voltage source 170
Selecting property it is applied to the second node of second resistor 154.
As can be seen that when switch 162 can be operated so that resistor 154 is directly connected to the power supply that we will be adopted as zero volt
When rail 152, then the voltage V at node 160AIt is given by
When switch 162 can be operated so that resistor 154 is connected to output voltage VMMeasurement voltage source 170 when, then obviously
See subsequent formula, it is evident that appear in V due to applying variable voltage caused by measuring signalAPlace, by following formula
It indicates
Therefore, voltage V is measuredMDevice is attenuated to decay with input signal exact same way.Therefore, searching and resistance
Voltage V at the node 161 of device 154MThe relevant output voltage V of changeAChange, make it possible to measure declining for attenuator 140
Lapse rate.
Although the transition between two states of square-wave waveform needs not be instantaneous and does not also use the identical duration,
But it can be for example by Operation switch 162 by VMIt is provided as square-wave-shaped waveform.
Fig. 7 shows the replacement embodiment of arrangement shown in Fig. 6.Specifically, the connection to switch 162 has been arrived
Replaced the connection of voltage follower 180 including operational amplifier 182, wherein the non-inverting input of operational amplifier is connected to
Digital analog converter 184, digital analog converter 184 are actuated to provide time-varying input signal VM(T).By with frequency overlapped-resistable filter
The voltage at 188 associated 186 measuring resistor of difference A/D converter, 154 both ends.If circuit is arranged on the integrated,
Then the performance of ADC 186 and DAC 184 can be well matched with, so that with its digital code phase is supplied to by data processor 50
Than the output voltage from DAC is accurately known.Data processor 50 can drive the output of DAC 184 in given frequency
Sine wave, square wave, piecewise approximation square wave or other random waveforms test waveform, and can be used and provided by ADC 186
Digitized signal search test waveform and extract it, to determine the transmitting of attenuator and associated signal processing circuit
Rate.
Voltage VMSize be much smaller than it is desirable that measurement supply voltage VinSize, and the two all decay it is identical
Amount.Therefore, measured voltage signal can flood the size of the voltage measurement signal of the operation for characterizing attenuator.It can be with
The signal exported by using the lock-in amplifier technology such as discussed about current measurement circuit or filtering from attenuator
Middle extraction voltage measurement signal.In addition, as shown in figure 8, can be decayed by the second voltage including resistor 152a and 154a
Device carry out supply voltage further measurement, resistor 152a and 154a substantially with formed by resistor 152 and 154 first
Voltage attenuator matching, but the voltages keep constant at the lower node of resistor 154a.It follows that if passing through subtraction
Device 190 is subtracted from the output of first voltage attenuator there is no the output of this of measuring signal attenuator, wherein the first decaying
The output of device includes dry voltage signal and voltage measurement signal, then the result of subtraction should leave voltage measurement signal VM', substantially
The contribution or interference of the upper not supply voltage at node 150.This method that can be completed in analog domain make by
VMCaused by deamplification VM' size more accurately with signal VMIt is compared, to more accurately establish the transmitting of attenuator
Function.This arranges that discussed method is similar previously with regards to the current measurement of Fig. 5.
Capacitor can be used rather than resistor formation voltage attenuator.
In Fig. 5, discusses in same conductor using two current sensors, can determine current sense to improve
The precision of the transmission function of device S2.
Fig. 9 shows equivalent arrangements, and wherein current sensor is separately positioned on now in individual conductor, i.e. energized conductor
12 and neutral conductor 14 in.In this arrangement, current sensor S1 has the current measurement signal for being applied to it, and electric current passes
Sensor S2 subtracts load signal from the output of S1 for estimating load current.In Fig. 9, sensor S1 and S2
It is although not shown current diverter, but they can be current diverter.In fact, sensor S1 and S2 can be by any
Suitable sensor technology is formed, such as current divider, power pack, Rogowski coil, magnetoresistive sensor, Hall effect
Device etc..If desired, sensor S1 and S2 can be formed by dissimilar technology.
The arrangement of Fig. 9 also provides some abilities that event is distorted in detection for instrument.In normal operating, and in instrument
Be not tampered with and in the case where load-side is there is no fault condition, then along the electric current of conductor 12 should in conductor 14
Corresponding equal and opposite currents match.However, if for example making to flow through by connecting other current divider around instrument
The electric current of S1 reduces and attempts to tamper with instrument, then the electric current in S1 and S2 will be no longer equal.Data processor 50 can be to this work
It responds out and takes movement appropriate.Movement appropriate may include sending alarm to electrical supplier or other remote entities, so as to
Take movement appropriate.Other movements may include setting caution sign, auto power off or remotely manage in response to coming from
The instruction of reason mechanism or internal rule table selectively disconnects power supply in certain hours.
Similarly, the estimated transfer function that the additional current divider connected around S1 will lead to S1 changes.Therefore, if
The rate of change of transmission function is more than threshold value, then may infer that the event of distorting.
Up to the present, all embodiments are described with the corresponding power supply with single electrification and single neutrality.
This power supply is very common in Europe.However, the split-phase power supply one that introduction described herein is also applied for and for example uses in the U.S.
It rises and uses, or be used together with the three phase mains usually found in the industrial case.
Figure 10 has schematically illustrated three phase mains, and wherein conductor L1, L2 and L3, which respectively has, is associated
Current sensor S1, S2 and S3.It is provided to current processing unit 201 in the voltage that the both ends current sensor S1 generate, with
Just the electric current I1 flowed in L1 is determined.The voltage at the both ends sensor S2 is provided to the second current processing unit 202 so as to true
Constant current I2, and the voltage at the both ends sensor S3 is provided to third current processing unit 203 to determine in power supply phase L3
The electric current I3 of flowing.Each of unit 201,202 and 203 may include the circuit described in Fig. 3,4,5 or about
Its modification.Therefore the electric current flowed in corresponding phase can be measured.Similarly, voltage tap is provided to measure conductor respectively
Line voltage V1, V2 and V3 of L1, L2 and L3.Voltage survey can be carried out as such as the tension measuring circuit described in Fig. 6 or Fig. 7
Amount.Each circuit can periodically bear inspection the transmitting response of its current sensor and its tension measuring circuit, with confirmation
Its transmission function drifts beyond user's restriction not from initial value drift or not from its previous estimation in each case
Surplus.
So far, it has just shunted sensor and has described circuit.For the sake of completeness, Figure 11 shows inductor sensing
Device is formed in the formation of the Rogowski coil 230, Rogowski coil around current-carrying conductor 240 in this case
With operation it is known to the person skilled in the art that and not needing to further describe herein.In Figure 10, Luo Kefu
This lubber ring is formed by the conductor of planar substrate either side.The conductor of upside is shown by a solid line, and the conductor of downside is shown with dotted line
Out.There is through-hole in the substrate, upper conductor is connected to lower conductor at each tie point, to be formed in around current-carrying conductor
The spiral path of the coil of advance.The output of Rogowski coil 230 is connected to integrator 246, so as to by Rogowski
The response of coil is converted to response substantially unrelated with frequency from the response proportional to frequency.The output of integrator can be by
Low-pass filter 248 is filtered to provide anti-aliasing function, is then digitized by analog-digital converter 250.When make measure electric current
IMWhen flowing in extra conductor 260, the output from Rogowski coil 230 is modified to indicate load current and measurement
The sum of electric current.Electric current can be made to measure as bipolarity (flowing in either direction), to increase by the presence of measurement electric current
Caused by ADC export effective change.Alternatively, it is possible to make to measure electric current as described in about Fig. 3 in current-carrying conductor
Middle flowing.
The electric current flowed in extra conductor 260 can provide by current source, such as be described by being similar to about Fig. 4
The circuit of circuit provides.The electric current flowed in extra conductor can be limited well by suitable current generating circuit, false
If can be used it is known and may the electric current that calibrated or the current generator equally poorly controlled, and can measure
The electric current that it is provided.Under any event, it is known that the response of measurement electric current and sensor all allows estimated transfer function.
Single current source/generator can be used in polyphase source, and can be division multiplexed each phase, Huo Zhe
In the case where using additional wire 260, line can pass through each current sensor.
When current sensor is power pack, arrangement shown in Figure 11 is same effective.Such as those skilled in the art
Known, the output of converter is loaded by loading resistor, and integrator 246 is omitted.
Therefore improved ammeter and dynamometer instrument can be provided, the deterioration of its electric current and voltage sensor can be monitored.
The instrument may include processor, which is suitable for the biography of current measurement channel and/or voltage measurement channel
The estimation of the change of delivery function or local transmission function, and movement appropriate is taken in the event that significant change occurs.It can
Alternatively or cumulatively, which can be arranged to send remote computation or data for transfer function data or change data
Treatment facility.Instrument can be arranged to respond the instruction from remote facility, such as to modify the reading of consumed amount of power
Number, either as from disconnected if the controller that power supply is drawn by certain times in one day or by its
It is interim to disconnect to limit the availability of power supply.If user is in arrears with their power consumption payment, these measures also can be implemented.
Claims (20)
1. a kind of equipment for determining the transmission function of current measurement arrangement, the equipment includes current transformer, the electricity
Current transformer is arranged to measure the first electric current passed through along the first conductor in use, which is characterized in that the equipment includes
Signal source and processing equipment, the signal source are arranged to supply reference signal, so that in use, the current transformer
Output include the current reference signal component as caused by the reference signal, the processing equipment is arranged to receive described defeated
Out and the reference signal is extracted to estimate the transmission function of the current transformer.
2. the equipment according to claim 1 for determining the transmission function of current measurement arrangement, which is characterized in that described
The size of reference signal has given value, so that according to the known dimensions of the reference signal and the current reference signal component
To calculate the transmission function of the current transformer.
3. the equipment according to claim 1 for determining the transmission function of current measurement arrangement, which is characterized in that described
Current transformer is calibrated during calibration steps, and the process equipment monitoring calibration after the current transformer biography
The change of delivery function.
4. the equipment according to any one of claim 1 to 3 for determining the transmission function of current measurement arrangement, special
Sign is that the reference signal is the electric current that interval applies, and makes it possible to intermittently determine the transmission function.
5. the equipment according to any one of claim 1 to 3 for determining the transmission function of current measurement arrangement, special
Sign is, the amplitude response of the reference signal in measured load current but it is variable.
6. the equipment according to any one of claim 1 to 3 for determining the transmission function of current measurement arrangement, special
Sign is that the equipment is arranged to estimate the size of first electric current.
7. the equipment according to any one of claim 1 to 3 for determining the transmission function of current measurement arrangement, special
Sign is that the current transformer is current diverter.
8. the equipment according to any one of claim 1 to 3 for determining the transmission function of current measurement arrangement, special
Sign is that the current transformer is inductosyn.
9. the equipment according to any one of claim 1 to 3 for determining the transmission function of current measurement arrangement, special
Sign is that the equipment includes the second current sensor for being arranged to measure first electric current, and is arranged to from the electric current
The subtracter of the output of second current sensor is subtracted in the output of mutual inductor.
10. the equipment according to any one of claim 1 to 3 for determining the transmission function of current measurement arrangement,
It is characterized in that, which further includes at least one extra current sensor, is flowed in one or more extra conductors with measurement
Electric current.
11. the equipment according to claim 1 for determining the transmission function of current measurement arrangement, which is characterized in that also
Including the voltage attenuator being connected between first conductor and reference mode, and cross over the impedance of the voltage attenuator
The tension measuring circuit of connection, further includes voltage signal source and processing equipment, and the voltage signal source is arranged to supply voltage
Reference signal, to modify the voltage at the reference mode between the first value and second value, so that the voltage attenuator
Output includes the voltage reference signal component as caused by the voltage reference signal, and the processing equipment is arranged to described in reception
It exports, extract the voltage reference signal and estimate the transmission function of the voltage attenuator.
12. the equipment according to claim 11 for determining the transmission function of current measurement arrangement, which is characterized in that institute
Processing equipment is stated also to be arranged to estimate the voltage of first conductor.
13. the equipment according to claim 11 or 12 for determining the transmission function of current measurement arrangement, feature exist
In the voltage reference signal being applied intermittently, so that the transmission function of the voltage attenuator is intermittently updated.
14. the equipment according to any one of claim 1 to 3 for determining the transmission function of current measurement arrangement,
It is characterized in that, which further includes the communication gate for transmitting data to remote computer.
15. a kind of kilowatt-hour meter, which is characterized in that the kilowatt-hour meter includes according to claim 1 for determining that electric current is surveyed
The equipment for measuring the transmission function of arrangement.
16. kilowatt-hour meter according to claim 15, which is characterized in that the kilowatt-hour meter further includes that energized conductor and neutrality are led
It current measuring transformer in body and is arranged to when the measured value for charging electric current and neutral current differs by more than predetermined threshold
The processor sounded an alarm.
17. kilowatt-hour meter according to claim 15, which is characterized in that the kilowatt-hour meter is suitable for operating with three phase mains.
18. kilowatt-hour meter according to claim 15, which is characterized in that the rate of change of monitoring current mutual inductor response, and
It is sounded an alarm if rate of change is more than threshold value.
19. a kind of kilowatt-hour meter, which is characterized in that the kilowatt-hour meter includes according to claim 11 for determining that electric current is surveyed
The equipment for measuring the transmission function of arrangement.
20. kilowatt-hour meter according to claim 19, which is characterized in that the kilowatt-hour meter further includes that energized conductor and neutrality are led
It current measuring transformer in body and is arranged to when the measured value for charging electric current and neutral current differs by more than predetermined threshold
The processor sounded an alarm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821135370.6U CN209086326U (en) | 2018-07-18 | 2018-07-18 | For determining the equipment and kilowatt-hour meter of the transmission function of current measurement arrangement |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201821135370.6U CN209086326U (en) | 2018-07-18 | 2018-07-18 | For determining the equipment and kilowatt-hour meter of the transmission function of current measurement arrangement |
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| CN209086326U true CN209086326U (en) | 2019-07-09 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114325419A (en) * | 2020-09-28 | 2022-04-12 | 亚德诺半导体国际无限责任公司 | DC signal measurement and battery formation/testing |
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2018
- 2018-07-18 CN CN201821135370.6U patent/CN209086326U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114325419A (en) * | 2020-09-28 | 2022-04-12 | 亚德诺半导体国际无限责任公司 | DC signal measurement and battery formation/testing |
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Effective date of registration: 20210702 Address after: Limerick Patentee after: ANALOG DEVICES INTERNATIONAL UNLIMITED Co. Address before: Limerick Patentee before: Analog Devices Global Unlimited Co. |