【正文】 論文的研究過程中，自始至終得到了她的悉心指導(dǎo)、鼓勵(lì)、關(guān)心和幫助。李老師平易近人的學(xué)者風(fēng)范和務(wù)實(shí)高效的工作作風(fēng)，無論在學(xué)術(shù)研究、實(shí)際工作，還是在為人處事中，都給我以深深的教益和啟迪在畢業(yè)設(shè)計(jì)期間，老師的諄諄教誨與無微不至的關(guān)懷使作者受益終生，不僅為今后從事科學(xué)研究工作培養(yǎng)了嚴(yán)謹(jǐn)、扎實(shí)、認(rèn)真的工作態(tài)度，而且還培養(yǎng)了樂觀上進(jìn)、積極進(jìn)取、團(tuán)結(jié)協(xié)作和頑強(qiáng)拼搏的工作精神，在此要向老師表示最衷心的感謝和敬意其次，要感謝機(jī)電學(xué)院車輛物流系韓以倫主任。在設(shè)計(jì)期間，主任經(jīng)常詢問進(jìn)度，并為我們解決了許多實(shí)際問題。最后還要感謝我們團(tuán)隊(duì)中的每一個(gè)成員，以及李如利、韓桐楓、于振江、林貞亮等同門在本文寫作期間的大力幫助!附錄A LabVIEW Based Instrument Current Transformer CalibratorXin Ai Hal Bao . Song 1) North China Electric Power University, Beijing, China 107206 2) Brunel University. UKABSTRACTThe Virtual Instrument (VI) mainly refers to build all kinds of instruments by software such as LabVIEW, which likes a real instrument build in a puter. Its39。 main characteristics are flexibility, multifunctions, multiple uses for one PC puter, 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 developed. This virtual calibrator can automatically measure the accuracy of 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 in 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 standard 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 mercial use. The main characteristic of Virtual Instrument 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 puter.The Instrument current transformer (TA) is widely used in all kinds of current measurement and it has the functions of protection, isolation and extending the measuring range. With the rapid development of puter measurement and control technology, and with the sequent 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 nonstandard TA secondary current may be 0 1A or lower. Although we have the technique to make this kind of calibrator by means of hardware such as single chip puter and electronic circuit, DSP and so on, it will cost too much money for these nostandard calibrator and will take too much time and the calibrator made by these hardware mill not be satisfactory in both function and practicality for designing all kinds of new TA.The calibrator that adopts VI technology not only can meet the requirements of the traditional one but also can satisfy customers with such advantages as multifunctions, convenience, and high ratio between performance and cost. The experiment results indicate that the virtual calibrator can provide excellent condition for TA measurement and design. The VI technology and personal puter must be widely used in the area of calibration on instrument transformer.Ⅱ. THE WORKING PRINCIPLE OF TA CALIBRATORThe error of TA includes ratio error and phase error. The measuring of the error of TA or the calibration of the accuracy of TA usually applies differential measuring method. The method needs a standard TA except the measured TA and a TA calibrator. There is the same turn ratio between the standard and measured T4 and the standard TA39。s accuracy should be 2 levels higher than the measured one. The calibrator function lies in forming parison circuits, measuring, and showing the error at all range. The parison circuit, also referred to the difference measuring principle circuit, is showed in Fig. 1. By measuring the voltage on I, and Rd, calculate the corresponding current. Then the calibrator can indicate the error.When a TA has the same turn ratio between the primary and secondary winding, the selfparison circuit could be used and is shown in . In the figures, TA0 and TAX are standard and TA being measured respectively. Np and Ns are primary and secondary winding turns. ip and io, id, i, are primary current secondary standard current, secondary error current, secondary current of TA being measured respectively. Ro and R,R, are secondary winding39。s resistance of standard TA, error current detecting resistance, burden 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 they represent the voltage on R, and R, respectively.In general, the TA calibrator39。s principle of the sample resistance should be: 1） it can not affect the accuracy of the parison circuit. In the ideal condition R, 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。 4） the magnitude of the sample resistance should make the sampled standard current and error 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 , R, is the error current sampling resistance 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 process and calculations.According to the TA error39。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 error. For the same principle, the relationship is equal to the voltage signal U, and ud. showed in . a and b is represent the ratio error and phase error separately. the TA39。s real ratio error C and phase error 6 can be found out through prope