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Worldwide analysis of recent wide area cascading failures has shown that very often they were mainly caused by the maloperation of the third zone of a distance protection relay. The load encroachment and power swing phenomena are the two dire problems to solve when dealing with the third zone of distance protection. The vast number of blackouts could have been avoided or the consequences lowered if...
Although there has been a practice of transposition of transmission lines, most of the real life EHV/UHV lines are untransposed. The distance protection of such lines becomes very complicated. With the advent of Global Positioning System (GPS) and Fiber optics technology, current differential protection can be a better choice for such lines. This paper proposes current differential protection scheme...
A transient fault information based IED integrating protection fault location, fault record, measurement and control functions for transmission line is proposed in this paper. IED hardware scheme adopts multiple CPU distributed structure, and includes mainly the following modules: process level communication module, protection module, fault location and record module, measurement and control module,...
This paper presents the measured impedance at the relaying point in the presence of Static Var Compensator (SVC), one of the shunt connected Flexible Alternating Current Transmission System (FACTS) devices; in the case of inter phase, phase to phase and three phase, faults. The presence of SVC on a transmission line has a great influence on the measured impedance at the relaying point. In the presence...
Distance relays used for transmission line protection can mal-operate on power swing. This paper presents protection schemes for out of step detection based on synchronized phasor measurement. Voltages and currents at both the ends of a transmission line are used to derive the parameters required for designing these schemes. The proposed schemes can distinguish stable and unstable power swing and...
This paper presents collected events to demonstrate the use of synchrophasor data to update and improve system models and system operation. Examples are given of responses to events captured using wide-area synchrophasor measurements. Phase angle, frequency, and voltage responses are displayed with discussion of the events, synchrophasor data views, and insights to be gained from the different data...
This paper presents a new impedance based fault location method in the case of phase to phase and three phase faults. This method utilized the measured impedance by distance relay and super imposed current factor, which is the ratio of post-fault current to super imposed current, to discriminate the fault position on the line. This method is robust against the fault resistance. The presented method...
Transmission line parameter is important for obtaining power network structure, generating power system node admittance matrix or impedance matrix to calculate power flow, calculating short-circuit current, and setting relaying protection devices. But actually, transmission line parameters applied in power system are mostly experience values or offline measuring values provided by manufacturers, they...
This paper presents an accurate fault location algorithm for double-circuit transmission lines with series capacitor compensation at both ends. It has been considered that a fault locator utilizes a communication channel of differential protective relays through it phasors of currents at both line ends are exchanged. Besides the phasors of two-end currents, three-phase voltage measured at a local...
For decades, various versions of the Takagi algorithm have been used by microprocessor-based relays for fault location. This system provides accurate fault location, limited by nonhomogeneous infeed, load flow, fault resistance, and series-compensated or parallel lines. With the emphasis placed on reliability in today's power system, the need for improved accuracy in fault location has increased....
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