Investigations On Design And Practicability Of High Voltage Electronic Transducers

As the capability and voltage level of transmission lines increasing, convertional inductive current transformers and potential transformers have several draws at extra-high voltage, and particularly ultra-high voltage grades. High voltage elecronic transducers replacing convertional transformers will be the certain developing tendency. There are two kinds of high voltage elecronic transducers: the optical transducers and the hybrid transducers. Of them, the hybrid transducer is most promising in the practical application for more mature technology and more operationg experience. This dissertation is devoted to correlative research on the practical application for several aspects, including product design of sensors, practical application of integrator for electronic current transducers, research on standardize interface, consturcture design of transducer and data fusion of multi-sensors.Rogowski coil is the current sensor. The basic principles of Rogowski coil are summarized, which include the equivalent circuit and the vector diagram of Rogowski coil, the analysis to static characteristic and transient characteristic, and the calculation of electomagnetism parameter. On the basis of theory, two industrial problems are discussed: the realization of exchangeability and temperature compensation. Capacitor voltage divider is the voltage sensor. The influence of stray capacitor to measurement is discussed, and the influence of transient element to the divider is analyzed.The performance of integrator is always one of the important factors which influence the accuracy and reliability of Rogowski current transducer. The analogue integrator has the advantages of simple structure, high response speed and large dynamic range. The digital integrator has the advantages of stable performance and high accuracy/The advantages of the latter have made it a hot problem of studying the utility of Rogowski current transducer in recent years. This paper puts forwards a set of methods of digital integrator designing for the first time, which include the choice of integration algorithm, the determine of the sampling rate and the resolution of the integration input, the universal structure of digital integrator, dealing with the input drift, the initial value and input saturation. Also it realizes a model of digital integrator and makes some experiments.The standard data interface is the demand of industrialization, and the assurance of high voltage elecronic transducer products entering practice, realizing exchanging and exoperating. In recent years, the conitual publication of the relative EEC standards makes it more urgent and necessary to study the standard interface of elecronic transducer. Taking the relative standardsnecessary to study the standard interface of elecronic transducer. Taking the relative standards of IEC as the studying object, according to the request of substation automatization to the elecronic transducers, this paper discusses elecronic transducer and its standard interface structure and model, and summarizes the designing method of standard interface, which include the analogue interface and the digital interface in IEC61850-9-1.According to the study of the standard interface of elecronic transducer, this paper put forward the whole designing idea based on standard interface and also concerning the system reliability and the electromagnetic compatible. With regard to standard interface, three problems are discussed: the synchronization of transducers, the low power design of circuit on the high voltage side and the realization of standard interface. For the reliability, the modle building method, the evaluation of system reliability and the method to improve reliability are discussed. In the electromagnetic compatible aspect, the electromagnetic disturbers and the method to deal with them are introduced.The structures of present hybrid current transducer are all open-looped. This open-looped structure is strict to every segment of transducer, which seriously limits the accuracy and reliability of elecronic transducer. This paper proposed a composition structure of Rogowski current transducer and low power current transducers with iron core. This structure is parallel and feedforward, which improve the measuring accuracy and reliability. It is also decrease the cost of production.Based on the theoretical analysis and experimental research, a combined 220kV/1250A transducer sample is completed and the experimental results are given. The sample is ready for field test, and the performance of field test is the next research content.