  With the increasing computations in power system simulations,
high-performance and cost-effective power system simulator is highly required.
In this paper, a cloud-computing based power system simulator, namely CloudPSS,
is designed. Based on an open service integrating framework, a self-developed
electromagnetic transients (EMT) simulator with an automatic code generator is
provided to accelerate EMT simulations using heterogeneous devices in the
cloud, such as CPU and GPU. Test results show that CloudPSS can achieve
significant speedups for both large-scale simulation tasks and multi-scenario
tasks. Moreover, benefit from the time-sharing of cloud computing resources,
the computational cost can be greatly reduced.
