Distance Protection Analysis For Long Transmission Line And Arc Effects On Distance Relay Using PSCAD

Distance relays are normally used to protect transmission lines. They respond to the impedance Between the relay location and the fault location as the impedance per mile of a transmission Line is fairly constant, these relays respond to the distance to a fault on the transmission line - and Hence their name as will be seen shortly, under certain conditions it may be desirable to make Distance relays respond to some parameter other than the impedance, such as the admittance or the Reactance up to the fault location. Electrical power is most important in everyday life it consists of generators, transformers, and transmission and distribution lines etc. system of protection offering considerable economic and technical advantages. Unlike phase and neutral overcurrent protection, the key advantage of distance protection is that its fault coverage of the protected circuit is virtually independent of source impedance variations during the transmissions faults can occur which cause damage to the power system process. The system also loses its stability and comfortable zones when fault occurs. When a fault occur in an element of a power system then automatic protective device is needed to isolate the faults element as soon as possible to keep the healthy section of the system in normal condition. A protective system includes circuit breakers and protective relays to isolate the faults section of the system from the healthy sections. These protective elements should be able to analyze the type of fault that occurred during abnormal conditions. In this, we have analyzed different kinds of faults over a transmission line placed between two buses. The simulation studies is carried out using PSCAD/EMTDC software, and the results obtained is verified theoretically. Distance relays are used to detect and protect from faults in transmission lines. A distance relay measures the impedance to the fault using the measured local voltage and current Modeling of distance relays offer an economical and feasible alternative to inquire the performance of relays and protection systems. In this thesis MHO Characteristics and Frequency Dependent (Phase) model type transmission line are modeled and simulated using PSCAD software. To study the performance of the relay characteristics, single line to ground fault with and without fault resistances and the arc effects are considered. A Fast Fourier Transform block and sequence components blocks in PSCAD/EMTDC have been used to extract the fundamental components. We can use all kind of transmission line 765,500,345,230, and 138kv.But in these thesis I am using Transmission lines 500kv,230KV 50 Hz transmission line systems.