外文翻譯----基于labview的電流互感器校驗(yàn)儀

1、附錄 附錄A LabVIEW Based Instrument Current Transformer CalibratorXin Ai Hal Bao Y.H. Song 1) North China Electric Power University, Beijing, China 107206 2) Brunel University. UKABSTRACTThe Virtual Instrument (VI) mainl

2、y refers to build all kinds of instruments by software such as LabVIEW, which likes a real instrument build in a computer. Its' main characteristics are flexibility, multi-functions, multiple uses for one PC computer

3、, giving high performance, and is less costly. In this paper, the VI technology is applied to the test and measurement of instrument current transformer (TA). By using the LabVIEW, the TA accuracy calibrator was develope

4、d. This virtual T.4 calibrator can automatically measure the accuracy of T.4 and can indicate the ratio error and phase error curves. The tests and calibration for the TA show that the virtual TA calibrator can be used i

5、n place of the traditional calibrator and is much better than the traditional one.Keywords：Instrument current transformer (TA), TA calibrator, Virtual Instruments, LabVIEW.I. INTRODUCTIONSince 1992 the VXIbus Rev.1.4 sta

6、ndard was established by the United States and LabVIEW was presented by the National Instruments co.(Nl), the Virtual Instrument (VI) have lain the foundation for its commercial use. The main characteristic of Virtual In

7、strument is that it makes instruments by software. Most of the traditional instrument can be developed by VI. The VI is a real instrument made by the personal computer.The Instrument current transformer (TA) is widely us

8、ed in all kinds of current measurement and it has the functions of protection, isolation and extending the measuring range. With the rapid development of computer measurement and control technology, and with the sequent

9、emergence of current transformer and transducer, there is an increasing number of current transformers with high accuracy and low secondary current. The standard TA secondary current is usually 1A or 5A: some non-standar

10、d TA secondary current may be 0 1A or lower. Although we have the technique of TA being measured respectively. Ro and R,R, are secondary winding's resistance of standard TA, error current detecting resistance, burde

11、n resistance of TA being measured respectively. To and K, Tb. T, are voltage sampling points which can calculate the current In this paper, only voltage between K and T, voltage between Tb and T, are being measured and t

12、hey represent the voltage on R, and R, respectively.In general, the TA calibrator's principle of the sample resistance should be: 1） it can not affect the accuracy of the comparison circuit. In the ideal condition R,

13、 and Rd should be 0, but it can not be sampled. So there must be sample resistance, in this paper, R, as shown in Fig, is used; 1） the magnitude of the sample resistance should make the sampled standard current and erro

14、r current in pro rata and should not have too much difference. The sampled resistance is set by experiment: R, is the secondary standard current sampling resistance and can be 0.1-0.50, R, is the error current sampling r

15、esistance and can be, R, is the burden resistance and it depends on the TA being measured. E$ sampling the voltage uo and U, on R, and R, respectively, the ratio error and phase error are showed on the LED through some

16、process and calculations.According to the TA error's phase diagram, when io is maximum, the value of id is the ratio error; when io changes from negative to positive and equals to 0, the value of id is the phase erro

17、r. For the same principle, the relationship is equal to the voltage signal U, and ud. showed in Fig.3. a and b is represent the ratio error and phase error separately. the TA's real ratio error C and phase error