DYNAMIC SIMULATION OF H.V.D.C. SYSTEM ON COMPUTERS

Abstract

The present work gives an introduction to HVDC systems and the method of simulation of HVDC system on digital and anolog-computers in a dynamic manner. The intro-duction also includes a list of hvdc projects and their expe-riences, main testings laboratories and stations and the necessity of dynamic simulatj.Q , Due to repetitive nature of the digital technique, jet has been given the name "Repetitive Process" by the ^author and is similar to the 'Central Process' 4€,Veloped. by Hingorani; Hay and Crosbie. Since valve actions are similar and repetitive in nature, the repetition of one such process enables one to simulate the continuous operation of the convertor, 'Repetitive Process' can be adopted in four different manners. The four different ways depend upon analy-tical and numerical state variable approaches using circulating current or voltage drop- calculations for defining the state of convertors at particular instant. State of convertor here means that whether the convertor is commutating or not. The technique is capable of giving voltage and current wave forms anywhere in the system under normal and abnormal conditions. For simplicity T-section of transmission line connecting two infinite a.c, sources, having a single bridge at each end has been considered` In addition to this convertor control systems, same as in central process representation have also been taken into account. The programs based upon the above techniques have been tested on digital computer IBM 7044, at I.I.T, Kanpur. Starting transients have also been studied on the above computer„ An attempt has also been made towards dynamic simulation of HVDC system on Analog computer. „ c Summary and conclusions give the comparison of different methods of simulation and further studies possible