Summary of the invention
Technical matters to be solved by this invention is: to the principle of work of existing capacitive apparatus insulated on-line monitoring system; But take into account the traceability of calibration equipment; A kind of capacitive apparatus insulated on-line monitoring system calibration equipment and method are provided; The demand of the capacitive apparatus insulated on-line monitoring system of verification is satisfied in accuracy, but and have a good traceability; The core thinking is: calibrating installation output amplitude ratio and phase differential be controlled 50Hz voltage and current signal accurately; Thereby effective verification work is carried out in the measurement that utilizes calibration equipment that the present invention designs and method can be electric capacity and dielectric dissipation factor to the main measurement function of capacitive apparatus insulated on-line monitoring system.
The technical scheme that the present invention adopted is: a kind of capacitive apparatus insulated on-line monitoring system calibration equipment; By controller, three signal generator modules, two precision current source modules, form with reference to accurate voltage source module and accurate voltage mutual inductor; It is characterized in that: the output control signal of controller connects the control end of said three signal generator modules respectively; Wherein there is the output of two signal generator modules to connect the input of corresponding two precision current source modules respectively; Said two precision current source modules are exported corresponding current component I1 and I2 respectively, and the output of normalized current signal is provided; The output of another one signal generator module connects said input with reference to the accurate voltage source module, and the output of said accurate voltage source module is connected with the former limit of said accurate voltage mutual inductor, the secondary output corresponding standard voltage signal U of accurate voltage mutual inductor.
Aforesaid capacitive apparatus insulated on-line monitoring system calibration equipment; It is characterized in that: said three signal generator modules adopt based on Direct Digital Synthesizer DDS chip AD9951 circuit and realize, can produce amplitude independently, the level and smooth sinusoidal signal unit of height that phase angle is adjustable.
Aforesaid capacitive apparatus insulated on-line monitoring system calibration equipment is characterized in that: said two precision current source modules and said the employing based on accurate amplifier OPA228 chip with reference to the accurate voltage source module constitute.
The present invention also provides a kind of capacitive apparatus insulated on-line monitoring system method of calibration, adopts aforesaid capacitive apparatus insulated on-line monitoring system calibration equipment, it is characterized in that, comprises the steps:
1) under the effect of controller; Each signal generator module produces amplitude independently, the level and smooth sinusoidal signal of height that phase place is adjustable; These sinusoidal signals to back level respectively independently the precision current source module, encourage with reference to accurate voltage source module, accurate voltage mutual inductor; Thereby form separate electric current and voltage drive signals; Current drive signal is through precision current source module outputting standard current signal I1 and I2, and voltage drive signals is then through driving accurate voltage mutual inductor, its secondary output reference voltage signal U;
2) through adjustment 1 road current signal and 1 road voltage signal; Perhaps the amplitude between 2 road current signals compares and phase differential; Simulate different electric capacitys and dielectric dissipation factor, thereby reach the purpose of capacitive apparatus insulated on-line monitoring system electric capacity of verification and dielectric dissipation factor measurement function.
The invention has the beneficial effects as follows: use this capacitive apparatus insulated on-line monitoring system calibration equipment; Can be the verification that electric capacity and dielectric dissipation factor measurement function carry out pin-point accuracy to the main measurement function of capacitive apparatus insulated on-line monitoring system, and the standard signal that is produced can make things convenient for, effectively carry out magnitude tracing.
Embodiment
In order to understand the present invention better, further illustrate content of the present invention below in conjunction with embodiment, but content of the present invention not only is confined to following embodiment.Those skilled in the art can do various changes or modification to the present invention, and these equivalent form of values are equally within the listed claims limited range of the application.
Mark among Fig. 1: 1-controller, 2,3,4-signal generator module, 5,6-precision current source module, 7-with reference to the accurate voltage source module, 8-accurate voltage mutual inductor, I1-electric current 1, I2-electric current 2, U-reference voltage.
Referring to shown in Figure 1, the capacitive apparatus insulated on-line monitoring system calibration equipment schematic diagram of the embodiment of the invention.Connect the control end of signal generator module 2,3,4 by the output control signal of controller 1, the output of signal generator module 2,3 connects the input of corresponding precision current source module 5,6 respectively, and precision current source module 5,6 is output as electric current 1 and electric current 2.The output of signal generator module 4 connects the input with reference to accurate voltage source module 7, is connected accurate voltage mutual inductor 8 secondary generation voltage output reference voltage U with accurate voltage mutual inductor 8 former limits with reference to the output terminal of accurate voltage source module 7.
Its principle of work is: under the control action of controller 1 (being specially TMS320F2812); Each signal generator module 2,3,4 (realizing based on DDS chip AD9951) can produce amplitude independently, the level and smooth sinusoidal signal unit of height that phase angle is adjustable; These sinusoidal signal unit can to back level separately independently precision current source module 5,6 (constituting) based on accurate amplifier OPA228 chip, encourage with reference to accurate voltage source module 7 (constituting), accurate voltage mutual inductor 8 based on accurate amplifier OPA228 chip; Thereby form separate current signal I1, I2 and voltage signal U; Amplitude and phase angle through adjustment current signal and voltage signal can simulate different electric capacitys and dielectric dissipation factor.
In the present embodiment, signal generator module 2,3,4 has taked to produce easily based on the Direct Digital synthetic technology of DDS chip that frequency stabilization is adjustable, amplitude stability is adjustable, phase stabilization is adjustable and the level and smooth stable sinusoidal signal of height of curve.
In the present embodiment, in design, taked the mode of " virtual medium loss factor standard ", designed precision current source module 5,6 and with reference to accurate voltage source module 7.
Calibration equipment principle of work: under the effect of control module; Each signal generator module can produce amplitude independently, the level and smooth sinusoidal signal of height that phase place is adjustable; These sinusoidal signals can to back level respectively independently the precision current source module, encourage with reference to accurate voltage source module, accurate voltage mutual inductor; Thereby form separate electric current and voltage drive signals; Current drive signal is through precision current source module outputting standard current signal, and voltage drive signals is then through driving accurate voltage mutual inductor, its secondary output reference voltage signal.Through regulating the amplitude ratio and the phase differential of 2 road current signals or 1 road current signal and 1 road voltage signal, finally reach the purpose of capacitive apparatus insulated on-line monitoring system electric capacity of verification and dielectric dissipation factor measurement function.
Signal generator module is taked the circuit based on Direct Digital Synthesizer DDS chip AD9951, comes to produce easily the sinusoidal signal that amplitude stability is adjustable, phase stabilization is adjustable and height of curve is level and smooth with the Direct Digital synthetic technology of DDS chip.Said two precision current source modules and said the employing based on accurate amplifier OPA228 chip with reference to the accurate voltage source module constitute.
Secondly, the present invention has also adopted following core technology in design:
1, the sinusoidal signal generation module of the adjustable and curve smoothing of frequency 50Hz, amplitude and phase stabilization
In order to reach the purpose of verification, at first need generate 3 basic sinusoidal signals, these sinusoidal signals will be used for encouraging rearmounted precision current source module and accurate voltage source module and producing corresponding standard current signal and reference voltage signal.In order at first to obtain the sinusoidal signal unit of the adjustable and curve smoothing of amplitude and frequency stabilization, having taked the Direct Digital synthetic technology is that the DDS chip produces sinusoidal signal.The Direct Digital synthetic technology can produce easily in the present invention that amplitude stability is adjustable, phase stabilization is adjustable and the level and smooth stable sinusoidal signal of height of curve.Wherein: the frequency of sinusoidal signal is highly stable 50Hz power frequency component; The accuracy of sinusoidal signal phase place can reach 0.0002rad; The sinusoidal signal curve is very level and smooth, can't see " ladder " through ordinary oscilloscope, the effect that this height is level and smooth can not used follow-up filtering circuit fully, thereby has significantly reduced the amplitude that filtering circuit brings and the negative effect of phase place.
2, realize " virtual medium loss factor standard " through design precision current source module and reference voltage source module.
The mode that the present invention has taked " module " to change in design to the precision current source circuit and the reference voltage source modular circuit of core.The input signal of each precision current source module and reference voltage source module is an independently sinusoidal signal; This signal is from the DDS chip; Under the excitation of the adjustable sinusoidal signal of amplitude-frequency independently; Precision current source module and reference voltage source module can be exported electric current, the voltage signal of different amplitudes, phase place respectively, and the precision current source module chosen high performance device, near the infinitely-great ideal current source requirement of output impedance.Between 2 road precision current source modules and precision current source module and adjustable, reach the purpose of simulation medium loss factor with reference to phase place precision between the accurate voltage source module.The present invention has formed following characteristics: output current signal and reference voltage signal amplitude and phase adjustment range are big.Can the analog electrical capacity through regulating the amplitude ratio, the control phase difference can the simulation medium loss factor, therefore can realize " virtual medium loss factor standard ".Amplitude and phase place through to voltage signal and electric current are traced to the source respectively, can guarantee trace to the source result's validity of this calibration equipment, have guaranteed the electric capacity that this calibration equipment produces and the accuracy of dielectric dissipation factor.
Adopt a kind of capacitive apparatus insulated on-line monitoring system method of calibration of capacitive apparatus insulated on-line monitoring system calibration equipment of the present invention, comprise the steps:
1) under the effect of controller; Each signal generator module produces amplitude independently, the level and smooth sinusoidal signal of height that phase place is adjustable; These sinusoidal signals to back level respectively independently the precision current source module, encourage with reference to accurate voltage source module, accurate voltage mutual inductor; Thereby form separate electric current and voltage drive signals; Current drive signal is through precision current source module outputting standard current signal I1 and I2, and voltage drive signals is then through driving accurate voltage mutual inductor, its secondary output reference voltage signal U;
2) through adjustment 1 road current signal and 1 road voltage signal; Perhaps the amplitude between 2 road current signals compares and phase differential; Simulate different electric capacitys and dielectric dissipation factor, thereby reach the purpose of capacitive apparatus insulated on-line monitoring system electric capacity of verification and dielectric dissipation factor measurement function.
The content of not doing in this instructions to describe in detail belongs to this area professional and technical personnel's known prior art.