It is very important to simulate transmission lines accurately in power system simulation. Now all kinds of real-time simulation tools have limitations to some extent. This paper presents the principle of electronic simulation of transmission lines and introduces the solutions of electronic simulation of lumped components， low-loss transmission lines and frequency-dependent transmission lines. The technology builds the equivalent model of transmission lines based on the mathematical model of electromagnetic interaction between conductors. In the model， those components of which values can be determined by the history record of sampled quantities are simulated by digital signal processors and the conversion between physical quantities and digital quantities is accomplished by A/D and D/A conversion units. Those components of which values are independent on the history record of sampled quantities and that reflect the relationship of instantaneous voltage and current are realized by themselves. An example simulation system for low-loss transmission lines verifies the feasibility of the proposed principle. The technology establishes the foundation for further exploration of power system simulation methods with space efficiency， low investment and convenient operation.