CN201438211U

CN201438211U - Electronic transformer calibrator

Info

Publication number: CN201438211U
Application number: CN2009200335796U
Authority: CN
Inventors: 张跟盈; 胡绍刚; 王世辉; 刘忠战
Original assignee: XI'AN HUAWEI OPTOELECTRONIC CORP; State Grid Liaoning Electric Power Co Ltd
Current assignee: XI'AN HUAWEI OPTOELECTRONIC CORP; State Grid Liaoning Electric Power Co Ltd
Priority date: 2009-06-17
Filing date: 2009-06-17
Publication date: 2010-04-14
Anticipated expiration: 2019-06-17

Abstract

The utility model relates to an electronic transformer calibrator, which comprises a standard transformer, an isolation circuit, an integrated operational amplifier circuit, an analog / digital converter, a photoelectric conversion module, a synchronous data acquisition circuit used for collecting signals and a computer used for processing collected signals. The standard transformer is connected with the isolation circuit, the isolation circuit is connected with the synchronous data acquisition circuit through the integrated operational amplifier circuit and the analog / digital converter in sequence, the photoelectric conversion module is connected with the synchronous data acquisition circuit, and the synchronous data acquisition circuit is connected with the computer. The utility model can realize the real-time calculation of the frequency, ratio and angular difference, the display of the waveform, effective value and other parameters, the storage and aggregation as well as other functions, and can obtain more accurate and stable measurements. The calculation speed of the utility model can completely satisfy the needs. Moreover, the utility model has the advantages of small size, easy carrying and high accuracy.

Description

A kind of checking electronic type transformers device

Technical field

The utility model belongs to high-voltage power metering and relay protection technical field, is specifically related to a kind of checking electronic type transformers device.

Background technology

At present, in the high voltage measuring field, because improving constantly of net capacity and electric pressure, cause increasing for the volume of a large amount of electromagnetic types of using, capacitance type potential transformer, cost is more and more higher, mutual inductor will adopt oil or SF6 gas-insulated, has environmental protection and potential safety hazard, is difficult to satisfy the requirement of modern digital power station to signal output.

In recent years, manufacturer has dropped into a large amount of human and material resources both at home and abroad, carries out the research and development of new-style electronic mutual inductor.Hyundai electronics formula mutual inductor has been cancelled the power requirement of signal output, and this provides possibility for development miniaturization, miniwatt electronic mutual inductor.Novel electronic formula mutual inductor is numeral output, and employing Optical Fiber Transmission, do not have interference, but metering has brought new problem to precision, at first standard mutual inductor is that simulation is exported, and tested mutual inductor is numeral output, if digital signal is reduced to simulating signal, use the classic method verification, the precision of digital signal will be lost very big, can't satisfy the checking precision requirement, it is the prerequisite of guaranteeing its successful Application in electric system that electronic mutual inductor is carried out verification.The utility model adopts analog signal digital, carries out computing with mathematics FFT method again, draws the error of standard mutual inductor and tested mutual inductor.Facts have proved that this method is very effective, significantly reduced the transmission error in the checking procedure, satisfy the verification requirement of user fully electronic mutual inductor.

The utility model content

The utility model has proposed a kind of checking electronic type transformers device at the problem that exists in the present checking electronic type transformers process.

A kind of checking electronic type transformers device, its special character is, this device comprises standard mutual inductor, buffer circuit, integrated operational amplifier circuit, A/D converter, photoelectric conversion module, in order to the synchronous data collection circuit of acquired signal with in order to handle the computing machine of acquired signal; Described standard mutual inductor inserts buffer circuit; Described buffer circuit inserts the synchronous data collection circuit by integrated operational amplifier circuit, A/D converter successively; Described photoelectric conversion module inserts the synchronous data collection circuit; Described synchronous data collection circuit inserts computing machine.

Above-mentioned synchronous data collection circuit is Programmable Logic Controller CPLD.

Above-mentioned standard mutual inductor is standard current transformer or standard potential transformer, and described buffer circuit is the current transformer of zero magnetic flux or the voltage transformer (VT) of zero magnetic flux.

Of the present utility model can be real-time calculate frequency, ratio and angular difference, and parameter such as display waveform, effective value, function such as realized storage, gather, can obtain more accurate, more stable measured value, and computing velocity can satisfy the demand fully, and this device has the advantages that volume is little, easy to carry, precision is high.

Description of drawings

Fig. 1 is a theory diagram of the present utility model;

Fig. 2 is circuit theory diagrams of the present utility model;

Circuit diagram when Fig. 3 is the verification electronic current transducer;

Circuit diagram when Fig. 4 is verification electronic voltage mutual inductor.

Embodiment

Referring to Fig. 1,2, checking electronic type transformers device described in the utility model comprises standard mutual inductor, buffer circuit, integrated operational amplifier circuit, A/D converter, photoelectric conversion module, in order to the synchronous data collection circuit of acquired signal with in order to handle the computing machine of acquired signal; Described standard mutual inductor inserts buffer circuit; Described buffer circuit inserts the synchronous data collection circuit by integrated operational amplifier circuit, A/D converter successively; Described photoelectric conversion module inserts the synchronous data collection circuit; Described synchronous data collection circuit inserts computing machine.

Wherein, described standard mutual inductor is standard current transformer or standard potential transformer, and described buffer circuit is the current transformer of zero magnetic flux or the voltage transformer (VT) of zero magnetic flux; The checking electronic type transformers device comprises that also this signal generator inserts standard mutual inductor in order to the signal generator of input signal to be provided; Signal generator is current feedback circuit or voltage generator; The synchronous data collection circuit is selected the CPLD of the EPM1270 type of ALTERA company for use.

Standard mutual inductor is producing output signal under the excitation of signal generator (current feedback circuit or voltage generator), this output signal is a simulating signal, and this simulating signal is taken a sample by integrated transporting discharging, obtains sampled signal; Again this sampled signal is converted to digital signal by mould/number conversion (A/D) chip; Again this digital signal is flowed to the synchronous data collection circuit, by the digital signal synchronized sampling of this synchronous data collection circuit to this digital signal and the output of tested electronic mutual inductor, and then acquisition sampled signal, at last this sampled signal is transferred to host computer by the USB modular circuit and this sampled signal is carried out FFT calculate, obtain the result of calculation of ratio (tested mutual inductor and standard mutual inductor when measuring-signal amplitude poor) and angular difference (tested mutual inductor and standard mutual inductor when measuring-signal phase place poor); Generally need to obtain a plurality of such result of calculations, the mean value of getting these a plurality of result of calculations promptly needs repeating step more than 1～5 time as last result of calculation (measurement result), generally repeating step 1～5 three time at least.

It is 500KHZ, mould/number conversion (A/D) chip of 16 that described mould/number conversion (A/D) chip adopts the highest sample frequency.

Wherein, the digital signal of tested electronic mutual inductor output is a light signal, so after this light digital signal need being converted to electric signal by photoelectric conversion module (circuit), flows to the synchronous data collection circuit again; And, in order to prevent the influence of standard mutual inductor to tested electronic mutual inductor, by buffer circuit the simulation output of standard mutual inductor is isolated, and the selecting for use can not have influence on tested electronic mutual inductor of ratings of the mutual inductor of this zero magnetic flux is as the criterion.

The synchronous data collection circuit here is Programmable Logic Controller CPLD.

Under non-synchronous sampling, traditional FFT exists leakage effect and fence effect, makes frequency, amplitude and the phase error calculated bigger, in order to reduce the influence of non-synchronous sampling to FFT, improves checking precision, and we adopt the high precision fft algorithm after the improvement.

By digital information processing knowledge as can be known, interpolation algorithm can be eliminated the error that fence effect causes, and windowing process can reduce leakage effect.In order to improve the precision of FFT, the utility model adopts the interpolation algorithm based on the Blackman2Harris window; The fundamental frequency variation range of line voltage is generally 49.15Hz～50.15Hz.

Windowed function in the algorithm of the present utility model is:

cyc＝4n

Num＝4k*cyc

pi＝3.1415926536

For?i＝0?To?Num

win(i)＝0.35875-0.48829*Cos(2*pi*i/Num)+0.14128*Cos(4*pi*i/Num)-0.01168*Cos(6*pi*i/Num)

Next?I

Wherein, cyc is the periodicity of each calculating sampling, and described Num is the total sampled point of each calculating; Described n 〉=1, k 〉=1, and described n and k all are natural numbers.

N=2 in present embodiment, k=24, i.e. each measurement in the utility model, 8 cycles (cycle) signal of sampling, so ripple 96 points (weekly in the phase sampling 96 times) (sample frequency is 4.8KHZ) weekly are N (Num)=96*8=768, (the actual need adopted some more, removes head and the tail in program).

In order further to reduce the error that the line voltage random fluctuation brings, obtain more stable measurement result, the automatic continuous sampling of system when each measurement the, calculating 10 times (each about 8 cycles), the mean value of getting 10 result of calculations is as last result.Facts have proved that this method can obtain more accurate, stable measured value, and computing velocity can be satisfied the demand fully.

Referring to Fig. 3,4, the measuring accuracy of the standard mutual inductor in the utility model is than high two grades of measuring accuracy of tested electronic mutual inductor, the measuring accuracy of standard mutual inductor is generally 0.1 grade or 0.01 grade, and described standard mutual inductor is meant standard current transformer CT 1 or standard potential transformer PT 2, and described tested electronic mutual inductor is the electronic current mutual inductor CT 3 or the electronic type voltage transformer PT 4 of optical fiber and digital output.

The output-current rating of the standard current transformer here is 5A; The rated output voltage of standard potential transformer is 100V/ √ 3V; Simultaneously, the specified output valve of corresponding current feedback circuit 5 or voltage generator 6 should satisfy the input current of this standard current transformer 1 or standard potential transformer 2 or the requirement of input voltage.

And the requirement for current feedback circuit 5 or voltage generator 6 in the utility model mainly is the requirement of satisfying tested electronic current mutual inductor CT 3 or electronic type voltage transformer PT 4, the rated current of for example tested current transformer CT 3 is 600A, and the output of the maximum of current feedback circuit 5 must be greater than 600A so.

The utility model adopts the power supply power supply of alternating current 220V ± 5%.

By the specified input in school: digital quantity (optical fiber or lead) CT/ metering: 2D41H (11585); CT/ protection: 1CFH (463); PT/ measures protection: 2D41H (11585); Standard mutual inductor input analog amount: CT:5A; PT:100/ √ 3V; 3.0 grades of checking precisions; Sampling precision is 16,80～500 points/cycle, the communication protocol of employing IEC-60044-8 standard.

Claims

1. checking electronic type transformers device is characterized in that: this device comprises standard mutual inductor, buffer circuit, integrated operational amplifier circuit, A/D converter, photoelectric conversion module, in order to the synchronous data collection circuit of acquired signal with in order to handle the computing machine of acquired signal; Described standard mutual inductor inserts buffer circuit; Described buffer circuit inserts the synchronous data collection circuit by integrated operational amplifier circuit, A/D converter successively; Described photoelectric conversion module inserts the synchronous data collection circuit; Described synchronous data collection circuit inserts computing machine.

2. checking electronic type transformers device according to claim 1 is characterized in that: described synchronous data collection circuit is Programmable Logic Controller CPLD.

3. checking electronic type transformers device according to claim 1 and 2 is characterized in that: described standard mutual inductor is standard current transformer or standard potential transformer, and described buffer circuit is the current transformer of zero magnetic flux or the voltage transformer (VT) of zero magnetic flux.