The busbar voltage phase measurement device of capacitance type potential transformer and method
Technical field
The present invention relates to electric power system power transformation equipment on-line monitoring technique field, particularly a kind of capacitance type potential transformer
Busbar voltage phase measurement device and method.
Background technology
In the open type transformer station of existing 220kV and above, the voltage transformer overwhelming majority is condenser type
Voltage transformer（CVT）.In the prior art, the reference phase of capacitance type equipment and metal oxide arrester on-line monitoring system
What position was chosen is CVT secondary side output voltage, and due to using the direct method gathering CVT secondary side voltage, this will be
CVT secondary side voltage output end accesses voltage coupling devices, and its shortcoming is：The voltage coupling devices accessing can take certain
CVT output capacity, the equipment of access can increase CVT secondary circuit short-circuit risk, and the error characteristics of CVT are not so good as electromagnetic type electricity
Pressure transformer is stable, and the change of system frequency, CVT secondary load size and power factor all can introduce additive error.Particularly
For the insulated on-line monitoring of electrical equipment, due to the restriction of systematic survey condition, voltage reference signal generally all takes from voltage
Transformer, therefore, the quality of voltage transformer directly influences the working condition of secondary device.Although the precision of CVT can reach
To 0.2 grade, but these additive errors still can bring considerable influence to insulated on-line monitoring.Sun Jiantao etc. delivers《Insulation is online
The error correction of capacitance type potential transformer in monitoring》In propose a kind of improved method, the method is in each time of CVT secondary side
All current transformer has been concatenated, this makes the method wiring in implementation process complicated, fitting function method used in literary composition in road
Computationally intensive, real-time is poor, and computational accuracy is relevant with iterationses.Additionally, this fixed phase measuring method still needs
Access voltage coupling devices in CVT secondary side, do not eliminate the operating potential risk of CVT.
Content of the invention
It is an object of the invention to provide a kind of busbar voltage phase measurement device of capacitance type potential transformer and method,
This device and method not only measures accurately, and real-time is good, and wiring is simple, affects little, safety to capacitance type potential transformer
Reliable.
For achieving the above object, the technical scheme is that：A kind of busbar voltage phase place of capacitance type potential transformer
Measurement apparatus, including：
First current transformer（CT1）, the middle voltage capacitance of described first current transformer access capacitance type potential transformer
Earth terminal, for collection in voltage capacitance earth current；
Second current transformer（CT2）, the middle transformation of described second current transformer access capacitance type potential transformer
The earth terminal of device, for gathering intermediate transformer earth current；
Current vector gathers computing unit, described current vector collection computing unit and described first current transformer, the
The outfan of two current transformers is connected, and is processed with the current signal to collection, and is converted to digital signal, Ran Houtong
Cross the instantaneous phase that numerical computations obtain the busbar voltage of capacitance type potential transformer.
Further, described current vector collection computing unit includes signal processing circuit, analog-digital converter and numeral letter
Number processor, described first current transformer, the second current transformer outfan respectively with signal processing circuit described in
Input is connected, and the outfan of described two signal processing circuits is connected with the input of described analog-digital converter respectively, institute
The outfan stating analog-digital converter is connected with the input of described digital signal processor.
The present invention also provides a kind of busbar voltage Method for Phase Difference Measurement of capacitance type potential transformer, comprises the following steps：
（1）First current transformer, the second current transformer are respectively connected to the middle voltage capacitance of capacitance type potential transformer
Earth terminal and intermediate transformer earth terminal；
（2）The current signal that first current transformer, the second current transformer will be coupled into respectively sends into signal processing electricity
Road, is amplified, filters etc. processing to the current signal of input；
（3）Current signal after processing is sent into analog-digital converter by signal processing circuit respectively, and current signal is changed
For digital signal；
（4）The digital signal that analog-digital converter obtains sampling sends into digital signal processor, is obtained by numerical computations
The instantaneous phase of the busbar voltage of capacitance type potential transformerθ；
WhenWhen, the wink of described busbar voltage
Shi XiangweiθFor：
WhenWhen, the wink of described busbar voltage
Shi XiangweiθFor：
Wherein, K represents intrinsic standoff ratio, I_{c}Represent and flow through middle voltage capacitanceC _{2}Electric current, I_{L}Represent and flow through intermediate transformer primary side
Electric current, j represents imaginary part, δ_{1}、δ_{2}Represent derided capacitors C respectively_{1}、C_{2}Dielectric loss angle, Re (), Im () represent respectively
The real part of complex function and imaginary part.
Compared to prior art, the invention has the beneficial effects as follows only piezoelectricity in CVT is gathered by high precision current transformer
Hold C2 earth current and intermediate transformer T1 earth current, in current vector collection computing unit, the current signal of collection is turned
Turn to digital signal, and obtain the instantaneous phase of CVT busbar voltage by numerical computations, voltage coupling devices need not be accessed, no
Only measure accurately, real-time is good, and wiring is simple, capacitance type potential transformer is affected little, safe and reliable, have very
Strong practicality and wide application prospect.
Brief description
Fig. 1 is the access state schematic diagram of apparatus of the present invention.
Fig. 2 is the composition structural representation of apparatus of the present invention.
Fig. 3 is the voltage being carried in capacitance type potential transformer on each device two ends and flows through the phase place between electric current
Relation vector figure.
In Fig. 1,C _{1}High-voltage capacitance,C _{2}Middle voltage capacitance,LCompensation reactor,TIntermediate transformer,R _{ d }Damping
Device,u、n、d _{ u }、d _{ n }Secondary Winding terminal and residual voltage winding terminals,C _{ x }Other capacitance type equipments on same bus,UBus Voltage,U _{1}High-voltage capacitanceC _{1}Both end voltage,U _{2}Middle voltage capacitanceC _{2}Both end voltage（Intermediate voltage terminal voltage-to-ground）,I _{ c }Flow through middle voltage capacitanceC _{2}Electric current,I _{ L }Flow through intermediate transformer primary side current,IFlow through high-voltage capacitanceC _{1}Electric current,θBusbar voltageUReal-time phase angle.
Specific embodiment
The busbar voltage phase measurement device of capacitance type potential transformer of the present invention, as shown in figure 1, include：
First Current Transmit 1, described first Current Transmit 1 accesses the middle voltage capacitance of capacitance type potential transformer
The earth terminal of C2, for voltage capacitance C2 earth current in collection；
Second Current Transmit 2, described second Current Transmit 2 accesses the middle transformation of capacitance type potential transformer
The earth terminal of device T1, for gathering intermediate transformer T1 earth current；
Current vector gathers computing unit, described current vector collection computing unit and described first current transformer, the
The outfan of two current transformers is connected, and is processed with the current signal to collection, and is converted to digital signal, Ran Houtong
Cross the instantaneous phase that numerical computations obtain the busbar voltage of capacitance type potential transformer.
As shown in Fig. 2 described current vector collection computing unit includes signal processing circuit, analog-digital converter and numeral letter
Number processor, described first current transformer, the second current transformer outfan respectively with signal processing circuit described in
Input is connected, and the outfan of described two signal processing circuits is connected with the input of described analog-digital converter respectively, institute
The outfan stating analog-digital converter is connected with the input of described digital signal processor.
The busbar voltage Method for Phase Difference Measurement of capacitance type potential transformer of the present invention, comprises the following steps：
（1）First current transformer, the second current transformer are respectively connected to the middle voltage capacitance of capacitance type potential transformer
The earth terminal of C2 and the earth terminal of intermediate transformer T1；
（2）The current signal that first current transformer, the second current transformer will be coupled into respectively sends into signal processing electricity
Road, is amplified, filters etc. processing to the current signal of input；
（3）Current signal after processing is sent into analog-digital converter by signal processing circuit respectively, and current signal is changed
For digital signal；
（4）The digital signal that analog-digital converter obtains sampling sends into digital signal processor, is obtained by numerical computations
The instantaneous phase of the busbar voltage of capacitance type potential transformerθ；
WhenWhen, the wink of described busbar voltage
Shi XiangweiθComplex representation form be：
WhenWhen, the wink of described busbar voltage
Shi XiangweiθComplex representation form be：
Wherein, K represents intrinsic standoff ratio, I_{c}Represent and flow through middle voltage capacitanceC _{2}Electric current, I_{L}Represent and flow through intermediate transformer primary side
Electric current, j represents imaginary part, δ_{1}、δ_{2}Represent derided capacitors C respectively_{1}、C_{2}Dielectric loss angle, Re (), Im () represent respectively
The real part of complex function and imaginary part.
Below to the present invention relates to related content be further described.
As shown in figure 1, flowing through middle voltage capacitance using high precision current transformer measurementC _{2}Electric currentI _{ c }, flow through middle transformation
Device primary side currentI _{ L }.ByI _{ c }、I _{ L }With busbar voltageUBetween phase relation, by calculating the real-time phase of busbar voltage
Position.The voltage that is carried in Fig. 1 on each device two ends and flow through phase relation between electric current as shown in vectorial Fig. 3.
Capacitance type potential transformer in normal work, voltage-dividing capacitorC _{1}Dielectric dissipation factor be tan δ_{1}, partial pressure electricity
ContainerC _{2}Dielectric dissipation factor be tan δ_{2}.Intrinsic standoff ratio is, line voltage angular frequency is ω.Busbar voltageUWink
Shi Xiangwei isθ.
Busbar voltageUWith electric currentI _{ c }、I _{ L }Between relation be：
Wherein voltage instantaneous vector calculate only with electric currentI _{ c }、I _{ L }, electric capacityC _{1}Dielectric dissipation factor tan δ_{1}, electric capacityC _{2}'s
Dielectric dissipation factor tan δ_{2}, capacitance partial pressure is more relevant than K, unrelated with the angular frequency of voltage and the capacitance of derided capacitors.
Voltage transient vector tangent value computing formula：
WhenWhen, described busbar voltage instantaneous
Phase placeθFor：
WhenWhen, the wink of described busbar voltage
Shi XiangweiθFor：
It is more than presently preferred embodiments of the present invention, all changes made according to technical solution of the present invention, produced function is made
With without departing from technical solution of the present invention scope when, belong to protection scope of the present invention.