National conference on power electronics and power systems 2008: Simulation of transient for power transmission lines

Switching operations, faults, lightning surges, and other intended or unintended disturbances cause temporary high voltages and currents in power transmission lines. The system must withstand this high voltage with a certain probability or its effects must be reduced and limited with protective devices. The simulation of transient phenomena is therefore important for coordination of the insulation as well as the proper design of the protection schemes. Such simulation is also needed to analyze unexpected transient phenomena after their occurrence.. By nature these phenomena are combinations of traveling wave effects on overhead lines and cables, and of oscillations of lumped circuits of generators, transformers and other devices. It is practically impossible to study these electromagnetic transients using hand calculations except for very simple cases. This complexity led to the simulation of transients using computer. Keywords: Pspice simulation, Telegrapher’s equation Transient, Travelling Waves.

[...] Understanding the transient behavior of the power networks during a fault or switching is of critical importance for power system protection, control and power quality analysis. So far, studies focus on accurate modelling of various power system components such as transmission lines, transformers, switching equipment, rotating machines as well as the control systems that interact with them. Significant work also exists in the area of simulation methods, most of which are developed to be used in the time domain. This paper analyzes simple cases of transmission lines such as line terminated to open circuit, short circuit and the two most well known protections for transients. [...]

[...] NATIONAL CONFERENCE ON POWER ELECTRONICS AND POWER SYSTEM 2008 RAJKOT The analysis of transient waves on a transmission line is frequently carried out by numerically integrating the ordinary differentialequations that describe a lumped RLC model of the line. This technique is practical for many purposes when implemented on a digital computer but requires the solution of a pair of differential equations for RLC section used to represent the line. In this work PSPICE software is used to simulate the lumped circuit model of transmission line. [...]

[...] Hence, it is obvious Figure 5 PSPICE Simulation for transmission Line and cable junction for step input Figure 6 PSPICE Simulation for transmission Line and cable junction for Exponential Input NATIONAL CONFERENCE ON POWER ELECTRONICS AND POWER SYSTEM 2008 RAJKOT Figure 7 PSPICE Simulation for transmission Line and cable junction for Ideal Lightning Input V. CLOSING OF REISISTORS FOR EHV LINES: Normally the transmission lines transmitting the voltages above 400KV are considered as EHV transmission lines. At the instant of energizing the line with the help of the circuit breaker with open circuit at load side, the transmission line experiences a voltage of magnitude around 3pu. [...]