Publisher helsinki university of technology, faculty of electronics, communications and automation. These faults can be identified and classified using discrete wavelet transform. Modelling the three phase transmission line system. Understanding the causes of line faults and the impact these have on the reliability of the transmission system can play an important role in decisionmaking for 1 planning and design, 2 maintenance and 3 operation of the network to improve reliability.
Protection of transmission lines are essential for quick system restoration and minimize the damage. Automatic classification of faults according to cause has primarily been explored as. Figure1 single line to ground lg fault figure2 line to line ll fault figure3 double line to ground llg fault figure4. The automatic location of faults can greatly enhance the systems reliability because the faster the system is restored, the more money and valuable time is saved. Two line to line faults the third type of shunt fault is the double line toground fault dlg in fig. Single line to ground faults, double line to ground faults, line to line faults and, three phase faults. The data are acquired through crio and post fault data generated for different types of fault are used to evaluate the performance of the proposed fuzzy logic based fault classification. Fault detection and classification in electrical power. Jul 09, 2015 the inputs were normalized with respect to their prefault values respectively.
Transient stability is very important in power system. Thecoaxial line is a transverse electromagnetic tem transmission line because both the electric and magnetic. Faults in parallel transmission line can be classified as shunt and series faults. A genetic based fault location algorithm for transmission lines. Fault detection for power transmission systems using. Protection of transmission lines by detecting line faults. Protective relay utilizes current and voltage signals to detect, classify, and locate the fault in transmission line.
Elnaggar assistant professor, college of technological studies, kuwait summary overhead transmission lines are parts of the electric power system where fault probabilities are generally higher than that of other system components. A genetic based fault location algorithm for transmission lines k. To develop practical methods and measures, and implementation of practical work. Transmission line protection is an important issue in power system because 8587% of power system faults are occurring in transmission line. The major faults in transmission lines are line to ground fault, line to line fault and three phase faults.
There are other types of faults such as line to line faults or double line to ground faults. Calculate the line inductancemeter and capacitance meter. Page 2 department of electrical engineering, nit rourkela, odisha, india 769008 certificate this is to certify that the work in this project entitled development of microcontroller based overcurrent relay. Various types of faults have been simulated at different locations along the transmission line.
Assume we have a transmission line in which air separated the two perfect conductors. Two kinds of symmetrical faults include line to line to line lll and line to line to line to ground lllg. It also directly affects the people life and indirectly to the growth of any nation. This dissertation work gives technique to classify the different faults on transmission line for quick and reliable operation of protection schemes. Types of faults in three phase system is shown in fig1. These indications should be fast enough to avoid instability of the system. The reduction in insulation causes excessive damage to the system.
The proposed method is tested for several faults simulated on an ieee 118bus test system and it has been concluded that it can detect and classify a fault using prefault and postfault recorded samples within 7 ms of. The number of the towers should be at least equal with the number given by expression 29. Refer to the microstrip transmission line applet and design a 33 ohm microstrip. Ieee transactions on power delivery 1 transmissionline fault. Instant isolation of fault is necessary to maintain the system stability. These lines are exposed to faults as a result of lightning, short circuits, faulty equipments, missoperation, human errors, overload, and aging. Jul 07, 2016 the hardware set up is connected properly. A case study the above named line is a short medium voltage overhead transmission line, being approximately 75 km long at 50hz and 33kv in tension shephered et al. Fault detection system in transmission line network. We represent as a large number of small inductors and capacitors spaced along the line. Transmission line setting calculations beyond the cookbook michael j. Two kinds of symmetrical faults include line to line to line lll and line to line to line to ground lllg as shown in figure below. In this case, the algorithm is tested for faults occurring at middle of the transmission line.
Nov 12, 2015 these faults rarely occur in practice as compared with unsymmetrical faults. Fuzzy logic based online fault detection and classification. This will result in discharge of the study committee b5 colloquium 2007 october 1520 316 madrid, spain. Detection and classification of one conductor open faults in. Contemporary power systems are associated with serious issues of faults on high voltage transmission lines. A genetic based fault location algorithm for transmission. Fault identification in electrical power distribution. Isbn pdf 9789512292455 issn pdf 17954584 language english number of pages 108 p. Two line to line faults the third type of shunt fault is the double linetoground fault dlg in fig. Example problem a 220kv, 150 mva, 60hz, threephase transmission line is 140 km long. Reasons for failure of transmission lines and their prevention strategies 3 other activities to promote electrical safety regulations, so that we fully understand the dangers of electricity, so that those desperate daunting, quit. Traveling wave fault location methods are usually more suitable for applicationto long lines. Heidfeld, schweitzer engineering laboratories, inc.
In this paper a new impedancebased fault location algorithm for seriescompensated lines figs. These faults rarely occur in practice as compared with unsymmetrical faults. Fault identification of overhead transmission lines. For fault detection and classification labview fuzzy logic tool kit has been used and the system is protected at 5 ms delay triggered using labview through crio controller relay module. At this point, i would like to express my sincere gratitude to prof. Assume the impedance of the line is 50 ohm, phase constant is 20 radm and the operating frequency is 700mhz. But during the transmission some faults are occurred in the system, such as ll fault line to line, 1lg fault single line to ground and 2lg fault double line to ground. Pdf transmissionline fault analysis using synchronized.
A transmission line is a specialized cable designed to carry alternating current of radiofrequency, that is, currents with a frequency high enough that their wave nature must be taken into account. The results shown in the paper is for line to ground fault only. Transmission line protection is an important issue in power system engineering because 8587% of power system faults are occurring in transmission lines. What are the different types of faults in power system. Pmu units provides real time measurement of positive sequence voltages and. Power transmission line fault detection and classification. To develop practical methods and measures, and implementation of. Transmission lines connect the generating stations and load centers. Both faultdetection and faultlocation indices are derived by using twoterminal synchronized measurements incorporated with distributed line model. Different types of faults can be viewed in following forms as shown in figures1,2,3 and 4. Fault classification in electric power transmission lines. Chengaiah2 1 mtech psoc, department of elect rical and electronics engineering, sri venkateshwara university college of engineeringtirupati517502india.
Fault detection in transmission line is important but at the same time type of the fault should also be indicated by protection scheme. The method adopted for the study is applied on single line diagram shown in fig. Among all these open conductor faults, the probability of occurrence of one open conductor faults is great. The other fault location techniques for such lines are based on knowledge based approaches 67. The fault creates the abnormal condition which reduces the insulation strength between the conductors. The signal speed along a transmisison line is predictable. Introduction protection of power system transmission line have great impact on the economic consideration of any state or country. Hon tat hui transmission lines basic theories nusece ee2011 28 example 1 a 100. The overhead line combined with underground cable is an intricate part of power system and is depend on for reliable transmission and distribution services. Faulty current and voltage signals are used for location, detection and classification of faults in a transmission network.
The transmission line is a twoport circuit used to connect a generator or transmitter signal to a receiving load over a distance. In this case also faults of all types lg, ll, llg and lllg are. In case of ac power system faults like phasetophase short circuits and phasetoearth faults there is a risk that commutation failures will occur in the hvdc converter. In transmission line faults, roughly 5% are symmetric. Power system fault analysis using fault reporting data of. Fault detection for power transmission systems using magnetic. A transmission line is a wire with a uniform goemetry along its length. Matti lehtonen for his invaluable guidance, encouragement, and support throughout this work. The main task of a transmission line is to maintain continuity of power supply from the generating station to the load centre, but this cannot be achieved because of line faults due lightning, storms, fog, and vegetation fall etc. Types of faults and effects in electrical power systems. Pdf transmission line fault detection and classification.
Locating transmission line faults quickly and accurately is very important for economy, safety and reliability point of view. Ground fault current distribution on overhead transmission. The line to ground fault lg is the most common fault and 6570 percent of faults are of this type. If the line cannot be considered long enough regarding to the ex. Fault identification in electrical power distribution system.
Types of faults in electrical power systems electronics hub. Types of faults in power system the fault in the power system is defined as the defect in the power system due to which the current is distracted from the intended path. In this case also faults of all types lg, ll, llg and lllg are incepted at 0. Detection of faults in the transmission lines by using 8051 microcontroller a thesis submitted in partial fulfilment of the requirement for the degree of bachelor and technology in electrical engineering department of electrical engineering national institute of technology rourkela by subham swagat patel 111ee0224. A new fault location algorithm for use with current. Ground fault current distribution on overhead transmission lines 77 in the expressions of the currents in ground wire and towers. The faulty voltage signals have been analyzed through wavelet transform using the db4 mother wavelet. This chapter discusses the classification of various faults at. It causes the conductor to make contact with the earth or ground.
Jiang 3 july 2008,had done the universal fault location technique for nterminal n3 transmission line based on synchronized phasors measurement unit. During the occurrence of faults, the grid current and. Transmissionline fault analysis using synchronized sampling article pdf available in ieee transactions on power delivery 292. The proposed algorithm is different from traditional multiterminal fault location techniques.
The protection system must be able to clear faults very quickly, i. Ieee transactions on power delivery 1 transmission. Detection of fault location in transmission line using internet of thingsiot velladurai s sarathkumar g. For the simulated system, faults occur at 150 km from either sending end or receiving end f2 in the figure 1a. The challenge trees pose to the reliability of overhead distribution. Sendingend port a a b b transmission line generator. Large disturbances like fault in a transmission line are a concern which needs to be disconnected as quickly as possible in order to restore the transient stability. Detection of fault location in transmission line using. With ground faults in the other hand, this coupling may cause substantial errors in the measurement. Faults in a power system can be created by natural events such as falling of a tree, wind, and an ice storm damaging a transmission line, and sometimes by mechanical failure of. This is in contrast to an asymmetrical fault, where the three phases are not affected equally. This 150mm2 wolf aluminiumconductors steel reinforced line has a resistance and a. Faults involving ionized current paths are also called transient faults.
The electric protection system must be able to detect all faults on the protected line the protection system must be able to discriminate between faults on the protected line and faults on adjacent lines, buses, transformers, etc. Transmission line setting calculations beyond the cookbook. We represent as a large number of small inductors and capacitors spaced. It has been observed through experimentation that 70 to 80% of the faults occurring on the transmission lines are single line to ground faults. An overview of transmission line protection by artificial. Different types of faults in electrical power system. Detection and classification of one conductor open faults. Transmission line fault detector robot linkedin slideshare. Transmission linefault detector robotabhisek anandc. Faults can be broadly classified into two main areas which have been designated active and passive. A trip signal will be sent by the relay to a circuit breaker with the purpose of disconnecting. A rough occurrence of symmetrical faults is in the range of 2 to 5% of the total system faults.
The proposed method is tested for several faults simulated on an ieee 118bus test system and it has been concluded that it can detect and classify a fault. Faults in a power system can be created by natural events such as falling of a tree, wind, and an ice storm damaging a transmission line, and sometimes by mechanical failure of transformers and other equipment in the system. Assuming ex,t 2cos3x1015t 107x vm, calculate the wave velocity. The transmission line conductors have resistances and inductances distributed uniformly along the length of the line. On a 400 kv double circuit overhead line measuring errors at the end of the line may for example be as large as 35% 1. It is able to detect all the ten types of faults i. As in the case of a large bird standing on one transmission line and touching the other, or if a tree branch happens to fall on top of two power transmission lines. Ag, bg, cg, ab, bc, ca, abg, bcg, cag and three phase symmetrical fault. This chapter discusses the classification of various faults at various location of the transmission line using ann. The characteristic parameters of the transmission line are.
This type could be represented as shown in the fig. It has been found that faults could occur in radial distribution systems with all possible combinations. Ground fault current distribution on overhead transmission lines. The most common type of fault on a three phase system are.