The method of testing of numeral output electronic mutual inductor transfer delay
Technical field
The present invention relates to the numeral method of testing of output electronic mutual inductor transfer delay time, belong to the electric-power metering technical field.
Background technology
Electronic mutual inductor is made up of the one or more curtage sensors that are connected to transmission system and secondary converter, is transferred to surveying instrument, instrument and relay protection or control device in order to will be proportional to measured amount.The interface of electronic mutual inductor and secondary device mainly contains 2 kinds of modes:
(1) digital signal with its output converts the low pressure analog quantity again into;
(2) its output directly links to each other with the secondary device of band digital interface.
Numeral output electronic mutual inductor comprises four unit: voltage and current sensor unit, primary transducer, optical fiber output unit, secondary converter.That the voltage and current sensor utilizes is electric, electronics, optics or other devices, produces voltage or the corresponding signal of electric current with a terminal place.Primary transducer is the light signal that is fit to Optical Fiber Transmission with the conversion of signals of voltage and current sensing unit output.Optical fiber is transferred to the secondary converter with signal.The secondary converter converts the measured signal that receives into and is fit to the light signal that merge cells is accepted, and is transmitted through the fiber to merge cells.
Four unit of numeral output electronic mutual inductor are called the sample conversion system of mutual inductor, and the digital quantity of the output FT3 of sample conversion system form offers merge cells.Merge cells will be synthetic continuous time from the electric current of secondary converter and voltage data, receive the data of a plurality of current/voltage mutual inductors, carry out synchronously, merges and export to device uses such as protection, observing and controlling after handling.
The transfer delay time of sample conversion system be an a certain analog quantity of terminal the appearance up time with the time of transmission during zero-time poor of corresponding twice transformation device output digital quantity; This transfer delay mainly comprises the transmission time of primary transducer, transmission system and the digital processing time of secondary converter, and this time is different inconsistent because of the ardware feature of different mutual inductors.
Adopt the merge cells of method of interpolation; Can the transfer delay of front-end sampling converting system be compensated; When there is error in the transfer delay of sample conversion system; The phase deviation that merge cells can not the full remuneration transfer delay brings causes the phase place of this road electric current of merge cells output, voltage digital amount overall offset to occur, causes the phase error of numeral output electronic mutual inductor not meet the demands; Therefore, sample conversion system transfer delay whether accurate is to guarantee qualified basic of numeral output electronic mutual inductor phase error.
Summary of the invention
The objective of the invention is, disclose and a kind ofly can export the method that the electronic mutual inductor sample conversion system transfer delay time detects numeral.An input quantity of electronic mutual inductor is the analog quantity of high voltage or big electric current, and the secondary output quantity is a digital quantity, can not directly test the transfer delay of electronic mutual inductor through existing testing tool.
High voltage or big current analog amount input that the inventive method is exported electronic mutual inductor with numeral insert the standard mutual inductor that detects usefulness, the secondary of standard mutual inductor is exported inserted the existing school of mutual inductor appearance; Numeral is exported the numeral of electronic mutual inductor and exported after the photoelectricity digital to analog converter converts simulating signal into, insert the existing school of mutual inductor appearance; The existing school of mutual inductor appearance can detect the angular difference of numeral output electronic mutual inductor
Ф 1, the angular difference of the accurate mutual inductor of bidding does
Ф 0, then the revised angular difference of numeral output electronic mutual inductor is:
Ф=
Ф 1+
Ф 0, the time that then converts into is:
T 1=
Ф/ 2
π fCan draw numeral output electronic mutual inductor sample conversion system the transfer delay time is:
T=T 1 -T 2
Wherein
T 2For the photoelectricity digital to analog converter converts digital signal switching time of analog quantity into,
T 2Value can record through oscillograph in the laboratory in advance.
Through an input quantity at numeral output electronic mutual inductor and standard mutual inductor is high voltage or big electric current, and appearance can draw the angular difference of electronic mutual inductor in existing school.If the existing school of mutual inductor appearance detects the angular difference of numeral output electronic mutual inductor
Ф 1The angular difference of standard mutual inductor
Ф 0Can from the examining report of censorship, draw, be known number; Then the revised angular difference of numeral output electronic mutual inductor does
Ф=
Ф 1+
Ф 0, the time that then converts into does
T 1=
Ф/ 2
π fConcrete detection method is seen Fig. 1, the test synoptic diagram of numeral output electronic mutual inductor transfer delay time.
Can draw numeral output electronic mutual inductor sample conversion system the transfer delay time is:
T=T 1 -T 2
Wherein
T 2For the photoelectricity digital to analog converter converts digital signal switching time of analog quantity into,
T 2Value can record through oscillograph in the laboratory in advance.Method of testing is seen Fig. 2, photoelectricity digital to analog converter its switching time
T 2The test synoptic diagram of value.
The beneficial effect of the present invention and prior art comparison is the transfer delay time through the present invention can accurately measure numeral output electronic mutual inductor, to have solved the underproof problem of digital output electronic mutual inductor phase error.
The present invention is applicable to the test use of numeral output electronic mutual inductor transfer delay time.
Description of drawings
Accompanying drawing 1 is the present invention's numeral output electronic mutual inductor transfer delay time test synoptic diagram;
Accompanying drawing 2 is photoelectricity digital to analog converter of the present invention its switching time
T 2The test synoptic diagram of value.
Embodiment
The specific embodiment of the invention is shown in the figure numbers test synoptic diagram of output electronic mutual inductor transfer delay time.
The present invention's numeral output electronic mutual inductor sample conversion system transfer delay time test method adopts the accurate mutual inductor of a station symbol (voltage or electric current), the existing school of a mutual inductor appearance, a photoelectricity digital to analog converter.Original just essential use examination criteria and detecting instrument when wherein the existing school of standard mutual inductor and mutual inductor appearance is other project of electronic mutual inductor (like ratio, angular difference) test, photoelectricity digital to analog converter are for testing special setting of numeral output electronic mutual inductor transfer delay.
Present embodiment is at first exported numeral the output access photoelectricity digital to analog converter of electronic mutual inductor; Numeral is exported the output light signal of electronic mutual inductor and changed back analog quantity, the secondary output analog quantity with standard mutual inductor is input to mutual-inductor tester again.An input quantity at numeral output electronic mutual inductor and standard mutual inductor is high voltage or big electric current then, and the existing school of mutual inductor appearance can detect the angular difference of electronic mutual inductor
Ф 1, then the revised angular difference of electronic mutual inductor does
Ф=
Ф 1+
Ф 0, wherein
Ф 0Be the angular difference of standard mutual inductor, can from the examining report of censorship, draw, be known number; Calculate as follows switching time:
T 1=
Ф/ 2
π f
Concrete detection method is seen Fig. 1, the test synoptic diagram of numeral output electronic mutual inductor transfer delay time.
Can draw numeral output electronic mutual inductor sample conversion system the transfer delay time is:
T=T 1 -T 2
Used its switching time of testing tool photoelectricity digital to analog converter in the test process wherein
T 2Value can record through oscillograph in the laboratory in advance.