Real time digital simulation for control and protection system testing

Today's power system environment is becoming more and more complex. Electrical power networks are being pushed closer to their limits, while at the same time higher reliability and efficiency are demanded. As a result, electrical equipment manufacturers are developing advanced equipment and installations to meet these requirements. Part of the challenge in designing such apparatus is the need to accurately simulate (prove) and test these devices before they are installed in an actual power system. The real time digital simulator (RTDS) allows developers to accurately and efficiently simulate electrical power systems and their ideas to improve them. The RTDS simulator operates in real time, therefore not only allowing the simulation of the power system, but also making it possible to test physical protection and control equipment. This gives developers the means to prove their ideas, prototypes and final products in a realistic environment. This paper will summarize the fundamental design of the RTDS simulator, with particular emphasis on recent developments and enhancements. It will also describe practical applications of the simulator in the various stages of power system design, testing and implementation. A brief description of ongoing development for the real time simulation of voltage source converter (VSC) converters is included.

I. Introduction

It has now been more than ten years since the introduction of the first fully digital real time power system simulator. Prior to the introduction of this technology, real time simulations were performed using scaled down analogue models of actual power system components. Many difficulties and inaccuracies were inherent in this approach. Furthermore, high purchase and operating costs prevented many organizations from acquiring and maintaining real time simulation tools.