Development Of A New 10kV Solid On-Load Tap Changer

At the present time, the mechanical 10kV OLTC (On-Load Tap-Changer) in using is not fully able to meet the requirements of 10kV power network such as fast, frequent voltage regulation and so on, because the OLTC has many deficiencies which are arcing, slow and not frequent voltage regulation. So this paper has developed a new mechanical-electronic OLTC and its intelligent controller for lOkV dry transformer named SOLTC (Solid On-Load Tap-Changer), which can satisfy the requirements of voltage regulation with no arcing, high speed and frequency.First, this paper has analysed traditional and other OLTC and designed the main circuit of SOLTC after introducing the meanings of on-load voltage regulation. At the same time, the whole procedure of voltage regulation without arcing is detailedly discussed in this paper. Then, this paper has also analysed the selection method of thyristors. In this section, the contact finger fabric of SOLTC has been more detailedly analysed, which has higher performances such as high stability and high reliability. It has also been checked according to corresponding norms and the checking results satisfy the requirements. Then, the paper simply narrates the main function, sampling algorithm and controlling logic of the intelligent controller.The key body in this paper is SOLTC controller's software and hardware, which is the focal point. The peripheral hardware interface circuits of the controller make high performance chip microprocessor MSP430F149 as central processor, which mainly contains , by different functions, the whole structure of controller, measuring electrical parameters circuits, triggering thyristors circuit and its emulation, controlling electric motor circuit, RS485 and GPRS communication units, LCD unit, power supply unit, hardware anti-interference and so on. The software of controller mainly contains the real-time sampling, A/D conversion, calculating parameters, automatic voltage regulation, communication and display module. At the same time, the software programs are given in this paper, which is compiled by C and assemble languages. The SOLTC can, on-load, automatically regulate voltage without arcing through intelligentcontroller. The controller with GPRS communication can real-time monitor SOLTC through the convenient internet, which greatly increases the intelligence of SOLTC.The SOLTC designed in this paper can safely, credibly and frequently regulate voltage with no arcing in power system, which effectiveness satisfies the requirements of power distribution network.