Different from fault locators using impedance methods, the location methods using traveling waves can achieve much higher accuracy regardless of fault type and line characteristics. The electrical contacts are designed as a transmission line with its characteristic impedance matched to. Transients in transmission lines free download as powerpoint presentation. Let the series impedance per unit length be z and the parallel admittance per unit length be y. A transmission line has distributed impedance parameters. Travelling wave based dc line fault location in vsc hvdc. This thesis investigates the problem of fault localization using traveling wave current signals obtained at a singleend of a transmission line andor at multiends of a transmission network. Ulaby, eric michielssen, and umberto ravaioli, fundamentals of applied electromagnetics c 2010 prentice hall exercise 2. In this chapter, we show how the same physics that leads to standing wave oscillations also gives rise to waves that move in space as well as time. Traveling waves on electric power systems project euclid. Traveling wave fault location in protective relays. The transmission line is a twoport circuit used to connect a generator or transmitter signal to a receiving load over a distance. The problems of traveling waves on the transmission lines of a power system1 differ considerably from those of traveling waves on telephone or telegraph. Transmission line parameters obtained from text module 2.
We then go on to introduce the important physical example of light waves. Transmission line protection based on travelling waves. Hvdc transmission lines and cables need repairs quickly as possible after a fault. Paper has made an attempt to obtain travelling waves components in the form of forward wave and backward waves from post fault components of voltage and current. Note that the coordinate used is l, which is distance from the end of the line. In an actual implementation of the traveling wave system in a relay, a sampling frequency of just over 1. It covers the topic travelling wave analysis from power systems.
Pdf transmission line protection based on travelling waves. Definition of traveling waves on transmission lines. Before going to electrical transmission line think of a swimming pool. The curve that shows the amplitude of the traveling wave at each point along the basilar membrane is called its envelope. You are disturbing the swimming pool, which is full, by jumping into it in one side of the pool or throwing something into it. A combined impedance and traveling wave based fault. Exact solutions of travelling wave model via dynamical system method wang, heng, chen, longwei, and liu, hongjiang, abstract and applied analysis, 2016. A travelling wave on a transmission line is a transient disturbance that that moves along the line at a constant speed yet maintains its shape see figure 1.
Such type of wave occurs for a short duration for a few microseconds but cause a much disturbance in the line. Pdf traveling wave fault location in power transmission systems. Time variation of the travelling waves along the line can be observed by calculating this pro. The transient wave is set up in the transmission line mainly due to switching, faults and lightning. Waves can exist traveling independently in either direction on a linear transmission line. What is meant by travelling waves in transmission power lines. Detecting and recording the traveling wave in this unit from two ends of a simulated transmission line produces the plot shown in fig. Section 2 the approximate nature of the transmission line equations t. Secondorder differential equation complex propagation constant attenuation constant neperm phase constant transmission line equation first order coupled equations. Two methods for travelling wave visualization in multi. Transmission line protection and fault location based on travelling wave measurement.
The analysis of travelling waves on power system transmission lines. Behaviour of travelling wave at a transition point. Examples include lightning surges, switching transients, faults, etc. Transmission lines a transmission line is used for the transmission of electrical power from generating substation to the various distribution units. Transmission line, travelling wave based protection, lightning stroke, characteristic of waveform, criterion 1. Write voltage and current wave equation of a transmission line.
Igbt based voltage source converter vsc hvdc systems are. The transmission line is made up of a conductor having a uniform crosssection along the line. In this paper, the performance of a twoterminal traveling wavebased fault location approach applied to a transmission line little longer than halfwavelength is. Pdf transmission line protection based on travelling. Transmission line protection using travelling waves generated at the time of fault are used as trip signals of a travelling wave relay. Travelling wave on transmission line is the voltage current waves which propagate from the source end to the load end during the transient condition. A transmission line is a twoport network connecting. The single ended travelling wave strategy is utilized to recognise the wave when it achieves both ends of the transmission line.
In 1 and in 5 is proposed a very simple method for fault location in a transmission line based on the transient fault location in transmission line based on the transient detection through the applying of. Fault location methods for transmission lines are broadly classified as impedance based method which uses the steady state fundamental components of voltage and current values,, traveling wave tw based method which uses incident and reflected tws observed at the measuring ends of the line, and knowledge based method which uses. A busbar capacitance has to be included in the model in order to represent the highfrequency properties better. The travelling wave fault locators twfl currently available on the market rely on. What is reflection and refraction of travelling waves.
Fault location in transmission line using travelling wave. The travelingwave photodetector twpd is a distributed structure in that optical and photogenerated electrical signals copropagate along the device length. The study of travelling waves helps in knowing the. Abstractfaults in power transmission lines cause transients that travel at a speed close to. Transmission lines signal transmission and reflection.
Transmission lines, fault location, traveling waves, impedance fault locators. Resistance along the line r inductance along the line l all. Pdf travelling wave based fault location analysis for. Introduction travelling wave protection or transient component based protection is capable of achieving ultra high speed fault detection, and hence it has been focused by electrical engineers all over the world for tens of. Unit iv traveling waves on transmission line sri vidya college of. At the point when transmission line fault happens, there is a change in both voltage and current.
Likewise, since the transmission line wave equation is a linear. Traveling wavebased fault location on halfwavelength. This is caused by the transient behavior of inductor and capacitors that are present in the transmission line. These waves travel along the line with the velocity equal to velocity of light if line losses are neglected. It presents the derivation and the solution to wave equations, lattice diagram and the event that occurs at the. So to examine the travelling wave signal, it takes the technique for karrenbauer. Long wire and traveling wave antennas 1 the power gain and directive characteristics of the harmonic wires which are long in terms of wavelength described in chapter 2 make them useful for longdistance transmission and reception on the higher frequencies. Paper has made an attempt to obtain travelling waves components in the form of forward wave and backward. Identification of lightning stroke and fault in the. Derivation of wave equations combining the two equations leads to. Hon tat hui transmission lines basic theories nusece ee2011 1 transmission lines basic theories 1 introduction at high frequencies, the wavelength is much smaller than.
Generally, as primary protection principle, travelling wave tw protection is adopted based on the technologies of abb and. The transmission line is represented as a distributed parameter model so that travelling wave effects will be apparent. It presents the derivation and the solution to wave equations, lattice diagram and the event that occurs at the junction of two or more lines. Ultrahighspeed travelling wave protection of transmission line using polarity comparison principle based on empirical mode decomposition dongwang, 1,2 houleigao, 1,2 sibeiluo, 1,2 andguibinzou 1,2. Pdf transmission line protection and fault location. Sendingend port a a b b transmission line generator circuit load circuit. Such a travelling wave movie may not only be useful for its educational value in classroom teaching of related subjects. Travelling wave based fault location analysis for transmission lines article pdf available in the european physical journal conferences 33. As the waves travel along the line their wave shapes and magnitudes are also modified. As known, voltage source converterbased highvoltage direct current vschvdc transmission system is widely utilised in actual power grid. The envelope has a positive and a negative side, but we generally only talk about the positive half because that. The travelling wave analysis consists of finding solutions of the telegraphers equations, bearing in mind the characteristics of the transmission lines, the equipment to which they will be connected and the nature of the signals likely to be experienced in power system transient situations. Travelling wave is a temporary wave that creates a disturbance and moves along the transmission line at a constant speed.
Existence of traveling wave solutions in a stage structured cooperative system on higherdimensional lattices li, kun, rocky mountain journal of mathematics, 2019. It is the best video to know how to prepare power systems for gate exam wherein we have. Then the line shown in the circuit on the left in fig. Travelling waves are the current and voltage waves which travel from the sending end of a transmission line to the other end when the switch is closed at the transmission lines starting end, voltage will not appear instantaneously at the other end. Even for this, the simplest travelling wave representation of a power system transmission line. Design, testing, and results stephen marx, bonneville power administration brian k. It transmits the wave of voltage and current from one end to another. Traveling waves theory the disturbance of the transmission line at any point is appears as a change in steady state power equation and propagate travelling wave in both directions of line terminals. It is suitable for asynchronous networking, such as the connection of offshore wind farm to main power grid. The power transmission line is the most frequently.