Design And Research Of Rogowski Current Transformer With High Performance

Current transformer (CT) in power system is essential for basic facilities. It provides the current data to power system measurement and protection, so the measurement accuracy and reliability of CT directly affects the safety and economy of power system operation. Along with the power system in monitoring, control and protection of the intelligent and automation development, the traditional type CT can not satisfy the requirements of the measurement, so new type current transformer began to appear. The Rogowski CT is one of them, which has the advantages of simple structure, high precision, excellent linearity, strong anti-interference ability, safe and convenient to use, easy to realize the digitization, networking and automation. So it has a very good application prospect.The research background is first introduced in this paper. Then the mainly two kinds of novel current transformer are discussed. And the domestic and international research status and development trend of CT are analyzed, which elaborates the significance of this research.Then sensing head of Rogowski CT is studied. On the based of analyzing the Rogowski coil's measuring principle, using MATLAB simulation, the impact of structure and electromagnetic parameters on the dynamic characteristics is studied. So the sensing head design scheme is put forward.In order to improve the band width of CT, the basic requirements of integral circuit part is analyzed, the integral circuit design scheme is put forward, the link of the working principle and design purpose is discussed. Using Multisim simulation, the frequency domain is analyzed, which validates the integral function. Then the whole Rogowski CT is produced.In order to improve the measuring precision of the Rogowski CT system, several optimization measures of sensing head and integral processing circuit are put forward, which further improve the CT system design scheme. Then Multisim simulation software is utilized to establish the simulation model of CT system. Using the simulation model, the power system prevalent in the three-phase short circuit fault current, national standards recommended by the 1.2/50μs type lightning current, high frequency pulse current are simulated, and have good results.Using the CT system, a large power frequency current, spherical gap discharge current and symmetry of the CT system are measured, and the linearity of it is discussed. It turns out the experimental measurements consistent with theoretical analysis results. Through the experimental analysis, the Rogowski CT system has 0.77mV/A sensitivity and 1.6Hz～1MHz bandwidth, which means it can be applied to power system in many places and many large current application. The research of high precision Rogowski CT with wideband shows that the whole Rogowski CT design scheme is reasonable, reliable and worthy of reference.